JP2003231509A - Top sealing type packaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a top sealing type packaging apparatus, which can prevent the occurrence of internal rupture of a film. <P>SOLUTION: According to the top sealing type packaging apparatus 1, the top opening of a tray T containing an object to be packaged is covered with a film Fm, which is welded to the rim of the opening of the tray T. The packaging apparatus 1 comprises rollers 3 and a roller slewing mechanism 8, and a controller. The rollers 3 comes in contact with the rim of the opening of the tray T, which is covered with the film Fm, to heat it. The roller slewing mechanism 8 moves the rollers 3 along the rim of the opening of the tray T. The controller makes the roller slewing mechanism 8 start the rollers 3 before they come in contact with the rim of the opening of the tray T. <P>COPYRIGHT: (C)2003,JPO

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 device.

[0002]

2. Description of the Related Art Conventionally, an overlap method has been widely 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 the tray is wrapped with the objects to be packaged and then the entire tray is wrapped with a film.

However, in the case of the overlap type, since the tray and the whole article to be packaged must be wrapped and films must be overlapped for sealing, the size is several times as large as the planar size of the tray. Film is required. This is an undesirable matter from the viewpoint of resource saving and garbage problems. Further, the films are often stacked on the bottom surface of the tray and pressed by pressing the bottom surface of the tray against the hot plate, which often results in poor sealing performance.

On the other hand, a method (hereinafter referred to as a top seal method) in which the peripheral portion of the tray opening and the film are heat-welded so that only the opening of the tray having an open upper surface is covered with the film is over. It is used in some parts instead of the lap method. In this top seal method, the amount of film used can be halved compared to the case where the overlap method is adopted.

Regarding the top-seal method, the applicant of the present application has developed a technique which has been previously published (Japanese Patent Application Laid-Open No. 2001-328608). There, the tray is pushed up from below against the held film to generate tension in the film, and in that state, a heat roller or the like is brought into contact with the opening peripheral portion of the tray from above the film to remove the tray peripheral portion. While heating, the heat roller and the like are moved along the peripheral portion of the tray opening. In this way, the film is welded to the entire circumference of the peripheral portion of the opening of the tray, and the film is fused outside the welded portion. As a result, it is possible to handle trays of various sizes and shapes regardless of the tray size and tray shape.

[0006]

When performing a packaging operation in such a top seal type packaging device, the operation of bringing the heat roller into contact with the peripheral portion of the opening of the tray and the heat seal along the peripheral portion of the opening of the tray. And the movement to move. At this time, when the operation of moving the heat roller along the peripheral portion of the opening of the tray is started after the operation of contacting the peripheral portion of the opening of the tray with the heat roller is completed, the peripheral portion of the peripheral portion of the tray opening with which the heat roller first abuts is started. The contact time between the heat roller and the heat roller becomes longer. Therefore, the amount of heat given to this portion by the seal roller becomes larger than the amount of heat given to the portion around the tray opening with which the heat roller that has reached the predetermined speed contacts. That is, a larger amount of heat is given to a part of the tray opening surrounding part than to the other part. For this reason, there is a high possibility that the film covering the peripheral portion of the opening of the tray will be cut off from this portion to cause in-film breakage.

Also, when the heat roller is stopped when the packaging operation is finished, the operation of moving the heat roller along the peripheral portion of the opening of the tray is stopped and then the operation of separating the heat roller from the peripheral portion of the tray opening. By doing so, the time during which the heat roller is brought into contact with the tray opening peripheral portion that is in contact when the heat roller stops. For this reason, as in the case described above, there is a high possibility that the film may be cut off from this portion.

An object of the present invention is to provide a top-seal type packaging device capable of suppressing the occurrence of film breakage.

[0009]

According to a first aspect of the present invention, for a tray having an open upper portion, the opening is covered with a film in a state where the articles to be packaged are accommodated in the tray, and the tray is provided around the opening. A top seal type packaging device for welding a film, comprising a heating unit, a moving unit and a control unit.
The heating means abuts and heats a peripheral portion of the opening of the tray covered with the film. The moving means moves the heating means along the peripheral portion of the opening of the tray. The control section starts the movement of the heating means by the moving means until the heating means comes into contact with the peripheral portion of the opening of the tray.

In this top seal type packaging device, when the heating means comes into contact with the peripheral portion of the opening of the tray, the heating means starts to move along the peripheral portion of the opening of the tray. That is, the heating means comes into contact with the portion around the opening of the tray while moving. For this reason, the contact time between the heating means and the peripheral portion of the opening of the tray does not become extremely long even at the first contact portion of the heating means, and is kept within a certain range at any portion of the peripheral portion of the opening of the tray. Can fit. As a result, in this top seal type packaging device, when starting the packaging operation, it is not concentrated in a part of the peripheral portion of the opening of the tray to give a larger amount of heat than the other parts, and the occurrence of film breakage is suppressed. be able to.

According to a second aspect of the present invention, for a tray having an open upper portion, the opening is covered with a film in a state where the article to be packaged is accommodated in the tray, and the film is welded to a portion around the opening of the tray. A packaging apparatus including a heating unit, a moving unit, and a control unit. The heating means abuts and heats a peripheral portion of the opening of the tray covered with the film. The moving means moves the heating means along the peripheral portion of the opening of the tray. The control unit stops the movement of the heating unit by the moving unit after the heating unit moving while being in contact with the peripheral portion of the opening of the tray separates from the peripheral portion of the opening of the tray.

In this top-seal type packaging device, the heating means stops after being separated from the portion around the opening of the tray.
Therefore, when the heating means is stopped, it is not in contact with the portion around the opening of the tray. Therefore, the contact time between the heating means and the peripheral portion of the opening of the tray does not become extremely long for a part of the peripheral portion of the opening of the tray, and should be kept within a certain range at any position of the peripheral portion of the tray opening. You can As a result, in this top-seal type packaging device, when the packaging operation is finished, it is not concentrated in a part of the peripheral portion of the opening of the tray to give a larger amount of heat than the other parts, and the occurrence of film breakage is suppressed. be able to.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION <Outline of Apparatus> A top seal type packaging apparatus according to an embodiment of the present invention is shown in FIGS. 1 and 2. The packaging apparatus 1 shown here has an upper opening O of a tray T containing fresh foods such as meat and fish and processed foods such as side dishes.
P is covered with a stretch film Fm (see FIGS. 3 and 4), and as shown in FIGS.
Flange located around P (portion around tray opening)
This is a device for sealing the FL and the stretch film Fm by heat welding.

<Device Configuration> This packaging device 1 includes a frame 1a, a tray placing and holding mechanism 2 for holding a tray T, four rollers 3 located above the tray placing and holding mechanism 2,
A film transport mechanism 5 for supplying the stretch film Fm between the tray mounting / holding mechanism 2 and the roller 3, a lift mechanism 6 for moving the tray mounting / holding mechanism 2 up and down, and a roller vertical movement mechanism 7 for mainly moving the roller 3 up and down. A roller revolving mechanism 8 having two revolving shafts for revolving the rollers 3 around the respective revolving shafts 81a and 81b, and a film holding mechanism for holding and stretching the stretch film Fm between the tray placing and holding mechanism 2 and the rollers 3. 9, stretch film F
It is composed of a sheet holding mechanism 10 for holding the four sides of the silicon film sheet SI arranged immediately above m, a control unit 11 (see FIG. 10) for controlling each mechanism, and the like.

<Detailed Configuration of Each Part> [Tray Placement / Holding Mechanism 2] The tray placement / holding mechanism 2 holds the tray T on its upper surface, and is lifted and lowered by the lift mechanism 6. Further, the tray placing / holding mechanism 2 can be pulled out from the position shown by the solid line in FIG. 2 to the position shown by the chain double-dashed 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 carried out manually by an operator, or it may be automatically transferred from a separately prepared tray T carrying device or the like. You may do it. Tray placing and holding mechanism 2
Holds the tray T placed on it by a plurality of holding members 22, 2
It is held so that the plane position does not shift by 3, 24, etc. (see FIG. 9).

[Roller 3] The roller 3 is a cylindrical member, and is rotatably supported by a roller support member 71 of a roller vertical movement mechanism 7 which will be 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 made of an elastic material such as resin or synthetic rubber, and even when the surface of the flange FL of the tray T has minute irregularities, the stretch film Fm and the flange FL are pressed against each other. It has been secured.

Further, as shown in FIG. 5, two rollers 3 are provided for each of 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. In this way, the roller 3
Are arranged as shown in FIG. 5 in a plan view, and are attached to the orbiting shafts 81a and 81b at an angle of about 110 °.

Further, as shown in FIGS. 1 and 2, these rollers 3 are supported by the roller support member 71 in a state of being inclined with respect to the upper surface of the tray T which is parallel to the horizontal plane when viewed from the side. Has been done. This tilt is caused by the turning shafts 81a, 8
The inclination is set so that the end of the roller 3 on the 1b side is located higher than the other end. A heater for heating the roller 3 is arranged inside the roller 3. The specifications of this heater are tray T and stretch film F to be sealed.
Appropriate specifications are selected in consideration of the necessity of inputting energy capable of recovering the amount of heat taken by the seal in a short time according to the material of m.

[Film Transport Mechanism 5] The film transport mechanism 5 includes the tray loading / holding mechanism 2 and the roller 3 which are in a lowered state.
While stretching the stretch film Fm between
It is a mechanism that winds up the stretch film Fm that is partially cut out by fusing due to sealing. As shown in FIG. 1, the film transport mechanism 5 includes a film setting unit 51.
And a film winding section 53 and a film transport section 52. The film setting section 51, the film transporting section 52, and the film winding section 53 are each supported by the frame 1a.

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

The film winding section 53 is provided for winding the remaining stretch film Fm, a part of which has been extracted by the packaging (top seal) of the tray T, and has a winding shaft 53a. This winding shaft 5
3a is rotated by a belt 53b that is wound around a motor 52c described later. The film transport unit 52 uses the feeding roller 52a and the feeding roller 52a to rotate the belt 5
It is provided with a motor 52c that is rotationally driven via 2b and a film support roller 52d. The stretch film Fm pulled out from the film roll R is rotated by the feeding roller 52a to drive the stretch film Fm.
Is sent to the side. Further, as the motor 52c rotates, the take-up roller 52a and the take-up shaft 53a also rotate, so that the stretch film Fm is taken up from the film roll R and taken up by the take-up shaft 53a. The rotation speed of the winding shaft 53a is set to be higher than the rotation speed of the payout roller 52a. Therefore, the stretch film Fm is in a state in which tension along the transport direction is applied. As a result, slack-free transportation is performed.

The feeding roller 52a has gripping property with respect to the stretch film Fm, and can suppress the slip and feed the stretch film Fm by a predetermined amount. Specifically, a one-way clutch (not shown) is provided to apply a mirror finish to the surface of the feeding roller 52a and prevent the feeding roller 52a from rotating in the reverse direction. The film supporting roller 52d is arranged in the vicinity of the film winding portion 53, and the height of the upper surface thereof is the payout roller 52a.
(See FIG. 1). Therefore, the portion of the stretched film Fm being conveyed between the feeding roller 52a and the film supporting roller 52d is kept horizontal.

[Film Holding Mechanism 9] The film holding mechanism 9 includes a film setting unit 51 to a film winding unit 5.
3 of the stretch film Fm continuing to 3 is gripped at both ends of the horizontal portion between the feeding roller 52a and the film supporting roller 52d,
This is a mechanism for stretching m in the width direction (left and right direction in FIG. 2). The film holding mechanism 9 includes a pair of film grips 91a and 91b extending in the film transport direction, and a stretch drive unit (not shown) that moves the film grips 91a and 91b in a direction orthogonal to the film transport direction (left and right direction in FIG. 2). have.

The film grip portions 91a and 91b are structured to grip the stretch film Fm from both upper and lower sides, and are turned on / off by a solenoid (not shown).
F will be done. Further, a rubber (or resin) pad having a large friction coefficient is attached to a portion in contact with the stretch film Fm from above, and the film grip portion 91 is provided.
The slip between the stretch film Fm and a, 91b is prevented.

[Lift Mechanism 6] The lift mechanism 6 is a mechanism for pushing up the tray placing / holding mechanism 2 holding the tray T with respect to the stretch film Fm and the silicon film sheet SI as shown in FIG. The lift mechanism 6 is rotatably attached to a drive motor 61, a large gear 62 axially supported by the frame 1a, a link member 63, a lever 64 whose one end is pivotally supported by the frame 1a at a fulcrum 64a, and a tip of the lever 64. It is composed of a mounted disc member 65 and the like.

When the drive motor 61 operates, the large gear 62 rotates via the gear fixed to the motor shaft. Then, the lever 64 is supported by the fulcrum 64a via the link member 63.
Rotate around. As a result, the tray placing / holding mechanism 2 whose lower surface is supported by the disc member 65 moves up and down (see FIGS. 2 and 3). The tray placing and holding mechanism 2
Is guided by a vertical guide rail 69,
The lift mechanism 6 operates to move in the vertical direction.

[Roller Vertical Movement Mechanism 7] The roller vertical movement mechanism 7 is a mechanism for changing the height position of the roller 3, and as shown in FIG. 1, a roller support member 71 for axially supporting the roller 3. The link mechanism 72, the pressing plate 73, a lever mechanism 74 that applies a force to the pressing plate 73 from above, and a motor 75 that operates the lever mechanism 74.

The roller support member 71 is arranged so that the roller 3 is in the inclined state shown in FIGS. 1 and 2 in a side view.
The roller 3 is pivotally supported. The dashed-dotted line in the roller 3 shown in FIGS. 1 and 2 is the rotation axis of the roller 3. One end of the link mechanism 72 supports the roller support member 71 by a pin, and the other end is pushed down by the pressing plate 73. When the other end of the link mechanism 72 is pushed down by the pressing plate 73, one end is raised as shown in FIGS. 1 and 2, and the roller support member 71 and the roller 3 are also raised. Become. On the other hand, when the pressing plate 73 stops applying the force to the link mechanism 72, the link mechanism 72 is caused by the weight of the roller support member 71 and the roller 3.
The other end of is lowered (see FIG. 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 placed on a rolling element (roller) axially supported by the other end of the link mechanism 72. [Roller Revolving Mechanism 8] The roller revolving mechanism 8 includes a roller 3, a roller support member 71 that supports the roller 3, and a link mechanism 7.
This is a mechanism for rotating 2 at a predetermined angle during seal packaging. The roller turning mechanism 8 mainly includes the first turning shaft 8
1a, 2nd turning shaft 81b, both turning shafts 81a, 81b
And a motor 82 for rotating the motor.

The lower end of the first turning shaft 81a is fixed to a base member 79 which supports the two link mechanisms 72, and the upper end thereof meshes with the main gear 83 via a gear. The main gear 83 includes a pulley and a belt 84.
Is connected to the motor 82, and is rotated by the operation of the motor 82. The lower end of the second turning shaft 81b has another 2
It is fixed to a base member 79 (a member different from the base member 79 to which the first turning shaft 81a is fixed) that supports one link mechanism 72. Further, the upper end of the second turning shaft 81b meshes with the main gear 83 via a gear (see FIG. 5).

The motor 82 turns the swivel shaft 81a by a predetermined angle,
When the roller 81b is rotated, each roller 3 moves to the first turning shaft 81
It is swung by a predetermined angle with the a or the second swivel shaft 81b as the center of rotation (see FIG. 6). In addition, in FIG.
For easy understanding, the roller 3 connected to the first turning shaft 81a is shown as rollers 3a and 3b, and the roller 3 connected to the second turning shaft 81b is shown as rollers 3c and 3d. Further, 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.

[Sheet Holding Mechanism 10] Sheet Holding Mechanism 1
0 is composed of eight sheet gripping units 100 and grips each of the four sides of the rectangular silicon film sheet SI at two places. As shown in FIG. 9, each sheet gripping unit 100 includes a fixing member 101 fixed to the frame 1a, a pin 102, a helical spring 103, and a sheet gripping member 104. One end of the spiral spring 103 is pin-supported by the fixing member 101 via a pin 102. The other end of the spiral spring 103 is connected to the sheet gripping member 104. The sheet gripping member 104 grips the silicon film sheet SI by sandwiching the silicon film sheet SI from above and below. The sheet gripping member 104
Has a structure for detachably gripping the silicon film sheet SI, and it is also possible to replace the silicon film sheet SI with a new one periodically, for example, once a month.

As described above, since the sheet gripping member 104 is pin-supported with respect to the fixing member 101, the tray T pushes up the stretch film Fm and the silicon film sheet SI by the operation of the lift mechanism 6. 3 and 9 from the state shown in FIG.
The state of the helical spring 103 or the sheet gripping member 104 changes as shown in FIG. That is, the spiral spring 103 and the sheet gripping member 104 rotate about the pin 102. When the tray T pushes up the central portion of the silicon film sheet SI,
The helical spring 103 is prevented from expanding and exerting excessive tension on the silicon film sheet SI.

[Silicon Film Sheet SI] The silicon film sheet SI is a rectangular sheet made of a silicon film, and is arranged on the stretch film Fm which is tensioned and held by the film holding mechanism 9 (FIG. 1).
And FIG. 2). This silicon film sheet SI
Is repeatedly used for a plurality of wrapping operations and does not require frequent sheet replacement.

Further, the silicon film sheet SI plays a role of transmitting heat from the roller 3 to a portion to be heat-welded when heat-welding the stretch film Fm to the flange FL of the tray T, as will be described later. Therefore, it is desirable to use the silicon film sheet SI having excellent thermal conductivity. Further, when the stretch film Fm is heat-welded to the flange FL of the tray T, the silicon film sheet SI comes into a state of being in close contact with the stretch film Fm from above. Therefore, after packaging, the silicon film sheet SI and the stretch film F
It is desirable to use the silicon film sheet SI that is as easy to peel from the stretch film Fm as possible so as not to interfere with the film transport and the lowering of the tray T by sticking to m.

[Controller 11] As shown in FIG. 10, the controller 11 is connected to the roller 3, the film transport mechanism 5, the lift mechanism 6, the roller vertical movement mechanism 7, the roller turning mechanism 8, the film holding mechanism 9, and the like. Then, each mechanism is controlled. The control contents of the control unit 11 will be described in the following description of the operation of the packaging device.

<Operation of Packing Device> [Placement of Tray T] The tray T holding the items to be packaged such as foods is placed on the tray placement / holding mechanism 2 which is pulled out to the position shown by the chain double-dashed line in FIG. When placed, the tray placing and holding mechanism 2 horizontally moves below the rollers 3 by hand or by a driving means (not shown).

The tray placing / holding mechanism 2 that has moved below the roller 3 positions the tray T by pushing the side surface of the tray T by the plurality of holding members 22, 23, 24, and prevents the tray T from being displaced. Hold the tray T. [Feeding out stretch film Fm] On the other hand, the film transport mechanism 5 feeds out the stretch film Fm to the film holding mechanism 9. When the stretch film Fm is fed out, the film holding mechanism 9 moves the stretch film Fm.
Hold m and stretch in the width direction (left-right direction in FIG. 2). As a result, the stretch film Fm is appropriately tensioned in the width direction and is in a wrinkle-free state. Note that, immediately above the stretch film Fm held by the film holding mechanism 9, as shown in FIGS. 1 and 2, the sheet holding mechanism 10 is provided.
The silicon film sheet SI held by is stretched.

[Push Up of Tray T] When the stretch film Fm is tensioned and held by the film holding mechanism 9,
The lift mechanism 6 raises the tray placing / holding mechanism 2 to move the stretch film Fm and the silicon film sheet S.
Push the tray T up against I (see FIG. 3). In this push-up operation of the tray T, first, the flange FL of the tray T contacts the stretch film Fm, and immediately thereafter, the portion of the stretch film Fm that contacts the flange FL contacts the silicon film sheet SI. Then, in this state, the tray T rises to a height position where heat welding is performed.

[Thermal welding] When the tray T is pushed up to the height position shown in FIG. 3, the control unit 11 controls the motor 75 of the roller vertical movement mechanism 7 to move the lever mechanism 74 downward to the pressing plate 73. The bias is released and the link mechanism 72 is opened. Then, the roller 3 starts descending due to its own weight or the like. Next, the control unit 11 sets the roller turning mechanism 8 until the roller 3 contacts the flange FL of the tray T.
The motor 82 is controlled to rotate the turning shafts 81a and 81b. As a result, the roller 3 starts rotating around the turning shafts 81a and 81b. Here, the controller 11 controls the roller 3
Starts to rotate and its angular velocity becomes substantially constant, and then each part is controlled so that the roller 3 contacts the flange FL of the tray T. That is, the roller 3 includes the turning shaft 81a,
It comes into contact with the flange FL of the tray T while rotating at a substantially constant speed around 81b. Further, since the rollers 3 are independent of each other, the rollers 3 come into contact with the flange FL of the tray T with substantially the same pressure. It should be noted that the roller 3 is provided on the silicon film sheet SI from the flange FL of the tray T and the stretch film F.
Hit the contact area with m.

The control unit 11 controls the motor 82 of the motor turning mechanism 8 to further rotate the turning shafts 81a and 81b after the roller 3 contacts the flange FL. Swivel axis 81
The rotation angles of a and 81b are set to 110 ° here so that the entire flange FL of the tray T is sealed by any of the rollers 3a to 3d (see FIG. 6). When the roller 3 rolls over the flange FL of the tray T from above the stretch film Fm by turning around the turning shafts 81a and 81b, the roller 3 heats the flange FL of the tray T and the stretch film Fm. Let it weld. At this time, the heat from the roller 3 is transferred to the contact portion between the flange FL and the stretch film Fm via the silicon film sheet SI.

An enlarged view of the vicinity of the contact portion between the two when the roller 3 moves along the periphery of the tray T,
It shows in FIG. The tray T is in a state where the opening OP is covered with the stretch film Fm. The stretch film Fm is pressure-bonded to the flange FL of the tray T. Then, the roller 3 obliquely hits the contact portion between the stretch film Fm and the flange FL from above while sandwiching the silicon film sheet SI, and applies heat and force. Due to the heat and force, the stretch film Fm and the flange FL are heat-welded. Further, at this time, heat and force are concentrated on the stretch film Fm in the outer portion of the top of the flange FL against which the roller 3 is abutted, so the stretch film Fm is melted and separated outside the heat-welded portion (see FIG. 8). .

When the sealing of the stretch film Fm on the tray T by the roller 3 is completed, the control section 11 pulls up the roller 3 and lowers the tray T. Here, the control unit 1
No. 1 stops the rotation of the roller 3 after separating the roller 3 from the flange FL of the tray T. That is, the roller 3
Stops rotating from the state of being in contact with the flange FL of the tray T while rotating, and then stops rotating from the flange FL. Then, the seal-wrapped tray T is taken out from the pulled-out tray placing and holding mechanism 2, and the process goes to the next cycle.

[Rewinding of Used Stretch Film Fm] When moving to the next cycle, the stretch film Fm cut out by heat-sealing a part by the seal packaging of the tray T is wound up on the winding shaft 53a. At this time, since the film supporting roller 52d and the feeding roller 52a are rotated by the rotation of the motor 52c, the stretching of the stretch film Fm for the next cycle (the feeding of the stretch film Fm to the lower side of the roller 3) is performed simultaneously with the winding. Be seen.

The width of the stretch film Fm is set to be wider than the width of the tray T at least when it is stretched by the film holding mechanism 9. The continuity of the stretch film Fm is not interrupted, and the problem that the film winding unit 53 cannot wind the film does not occur.

<Characteristics of the packaging device of the present embodiment> In this top seal type packaging device, the roller 3 is centered on the pivot shafts 81a and 81b before contacting the flange FL of the tray T when starting the packaging operation. The rotation of the tray T is started at a substantially constant speed along the flange FL of the tray T. That is, the roller 3 comes into contact with the flange FL of the tray T while moving at a substantially constant speed.

If the stationary roller 3 is attached to the flange F,
When the rotation of the roller 3 is started after the roller 3 is brought into contact with L, the roller 3 should be in contact with the flange FL of the tray T for a longer time than the other portions in the vicinity of the portion with which the roller 3 originally abuts. become. In this case, a larger amount of heat is applied to this portion than other portions, so that the stretch film Fm is melted and the strength of the stretch film Fm is likely to decrease. For this reason, the stretch film Fm that covers the tray T is likely to cause inward cutting.

However, in this top seal type packaging device, the roller 3 comes into contact with the flange FL of the tray T while moving at a substantially constant speed. Therefore, the time for the roller 3 and the flange FL to come into contact with each other does not become extremely long even at the portion where the roller 3 first comes into contact, and can be kept within a certain range at any position of the flange FL of the tray T. it can. As a result, in this top-seal type packaging device, when the packaging operation is started, the flange FL of the tray T is
It is not necessary to concentrate more heat on one part of the stretch film than on the other part, and it is possible to suppress the occurrence of incision in the stretch film Fm.

Further, in this top seal type packaging device,
The roller 3 stops rotating after being separated from the flange FL of the tray T when finishing the packaging operation. Therefore, the roller 3
Is not in contact with the flange FL of the tray T when is stopped. If the roller 3 stops rotating, the roller 3
When is separated from the flange FL of the tray T, the vicinity of the portion that was in contact with the flange FL when the roller 3 was stopped is in contact with the roller 3 for a longer time than other portions. In this case, the stretch film Fm is apt to cause inward cutting for the same reason as described above.

However, in this top seal type packaging device, the flange F of the tray T is used when the roller 3 is stopped.
Not in contact with L. Therefore, the time for the roller 3 and the flange FL of the tray T to come into contact with each other does not become extremely short for a part of the flange FL of the tray T, and can be kept within a certain range at any position of the flange FL. With this, in this top seal type packaging device,
When the wrapping operation is finished, it is no longer concentrated on a part of the flange FL of the tray T to give a larger amount of heat than the other parts, and it is possible to suppress the occurrence of incision of the stretch film Fm.

[0052]

In the top seal type packaging apparatus according to the present invention, when the heating means comes into contact with the peripheral portion of the opening of the tray, the heating means starts to move along the peripheral portion of the opening of the tray. That is, the heating means comes into contact with the portion around the opening of the tray while moving. For this reason, the contact time between the heating means and the peripheral portion of the opening of the tray does not become extremely long even at the first contact portion of the heating means, and is kept within a certain range at any portion of the peripheral portion of the opening of the tray. Can fit. As a result, in this top seal type packaging device, when starting the packaging operation, it is not concentrated in a part of the peripheral portion of the opening of the tray to give a larger amount of heat than the other parts, and the occurrence of film breakage is suppressed. be able to.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of the packaging device.

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

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

FIG. 5 is a plan view of rollers.

FIG. 6 is a diagram showing a plane locus by the rotation of a roller.

FIG. 7 is an enlarged view of the vicinity of the flange of the tray when the rollers are in contact with each other.

FIG. 8 is an enlarged view of the vicinity of the flange of the tray during film heat welding.

FIG. 9 is an enlarged view of the vicinity of the roller and the tray during film welding.

FIG. 10 is a block diagram of a control unit and each mechanism.

[Explanation of symbols]

1 Top seal type packaging equipment 3 rollers (heating means) 8 Roller rotation mechanism (moving means) 11 Control unit T tray OP opening FL flange (around the opening) Fm stretch film (film)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Norio Kawanishi             1 959 Shimohagi, Ritto City, Shiga Prefecture             Fern Shiga Office F-term (reference) 3E049 AA05 AA10 AB03 BA04 BA10                       CA08 DA01 DB01 EB03 EC02                 3E094 AA04 BA12 CA10 DA01 EA06                       FA04 FA13 GA02 GA11 HA08

Claims (2)

[Claims] 1. A top-seal wrapping device for a tray having an open upper part, wherein the opening is covered with a film in a state where an object to be packaged is accommodated in the tray, and the film is welded to a peripheral portion of the opening of the tray. A heating means for contacting and heating an opening peripheral portion of the tray covered with a film; a moving means for moving the heating means along the opening peripheral portion of the tray; And a control unit for starting the movement of the heating means by the movement means before the movement of the heating means is brought into contact with the peripheral portion of the opening. 2. A top-seal wrapping device for a tray having an open upper part, wherein the opening is covered with a film in a state where an object to be packed is accommodated in the tray, and the film is welded to a peripheral portion of the opening of the tray. A heating means for contacting and heating an opening surrounding portion of the tray covered with a film; a moving means for moving the heating means along the opening surrounding portion of the tray; and an opening surrounding portion of the tray. A top-seal type packaging device, comprising: a control unit that stops the movement of the heating unit by the moving unit after the heating unit moving while contacting with is separated from the opening peripheral portion of the tray.