JP5205156B2 - Center seal device - Google Patents

Description

  The present invention relates to a center seal device in an automatic packaging machine.

  A pillow packaging machine, which is one form of a packaging machine, has the following configuration. First, the strip-shaped film wound up by the raw fabric roll is continuously supplied to the bag making device, and when the bag making device is passed, the tubular film formed into a tubular shape is formed. In addition, an article transporting and supplying device is arranged on the upstream side of the bag making device, and an object to be packaged conveyed at predetermined intervals from the object to be packaged conveying and supplying device is supplied into the bag making device. Accordingly, when the article to be packaged passes through the bag making machine, the article to be packaged is stored at predetermined intervals in the cylindrical film, and the article to be packaged is conveyed together with the cylindrical film. A center seal device and an end seal device are arranged along the conveying direction. The center seal device seals the film polymerization end of the tubular film. The end seal device seals the tubular film in the lateral direction of travel (portion where the front and rear packages are not present) and cuts the portion of the tubular film in which the front package is stored. Is separated from the subsequent cylindrical film to produce a package.

  The center seal device includes a bar type (a pair of fixed rectangular parallelepiped bar sealers sandwiching the film polymerization end of the tubular film) and a rotary type (a pair of rollers sandwiching the film polymerization end of the tubular film) ) An example of the bar-type center seal device is disclosed in Patent Document 1. As shown in FIG. 1, this center seal device includes a pair of elongated rectangular parallelepiped metal bar sealers 1.

  The bar sealer 1 has a built-in heater, and the metal bar sealer 1 as a whole is heated by the heater. Further, the pair of bar sealers 1 are moved toward and away from each other by a predetermined driving mechanism, and as shown in FIG. 1B, a constant space K is formed between the pair of bar sealers 1 when they are separated from each other. Then, the film polymerization end 2 of the tubular film is inserted and disposed in the space K.

With the space K thus formed, the heater is energized to generate heat, and the entire bar sealer 1 is heated. At this time, a temperature sensor such as a thermocouple 3 is inserted and arranged at the upstream end of the tubular film of each bar sealer 1 in the traveling direction so that the heater operates so that the temperature of the bar sealer 1 is stabilized at the target value. Control. Then, when the temperature is stabilized at the target value, the pair of bar sealers 1 are brought close to each other. Then, as shown in FIG. 1 (a), the film polymerization end 2 is located in a slight gap formed between the bar sealers 1 and is heated. Therefore, when the tubular film (film polymerization end 2) moves forward between the bar sealers 1, it is heated by the bar sealer 1, and the film polymerization end 2 is heat-sealed and sealed.
JP-A-8-119208

  However, the bar sealer 1 type center seal device having the structure shown in Patent Document 1 has the following problems. That is, the surface temperature of the bar sealer 1 of the center seal device is stable in a long operation stop state (the state where the bar sealer 1 is separated from each other and is not in contact with the film polymerization end 2). When the sealing surface of 1 comes into contact with the film polymerization end 2, the heat of the bar sealer 1 is taken away by the moving cylindrical film (film polymerization end 2), so that the surface temperature of the bar sealer 1 is lowered. There is a problem. This phenomenon is particularly remarkable in a packaging machine having a film peripheral speed of 30 m or more, and in a film material made of an aluminum vapor deposition film. Therefore, at the start of operation, the stability of the surface temperature of the bar sealer is lacking, which may cause a seal failure due to this.

  An object of this invention is to provide the center seal apparatus which can carry out the heat sealing stably with respect to the superposition | polymerization end of a cylindrical film immediately after a driving | operation start.

  In order to achieve the above-described object, the center seal device according to the present invention includes (1) a means for forming a continuously supplied belt-like film into a cylindrical shape, and polymerization of the cylindrical film formed in the cylindrical shape. The center used in an automatic packaging machine provided with a center seal device that seals an end and an end seal device that is disposed downstream of the center seal device and seals and cuts in the width direction of the tubular film A sealing device comprising a pair of rod-shaped bar sealers that sandwich the overlapping end from both sides, so that the volume of the bar sealer on the downstream side in the traveling direction is larger than the volume on the upstream side in the traveling direction of the tubular film. I made it.

  (2) It is preferable to increase the volume on the downstream side in the traveling direction by changing the thickness of the bar sealer from the sealing surface to the opposite surface. (3) The bar sealer may include a rectangular parallelepiped sealer main body and a metal auxiliary member connected to a downstream side surface of the sealer main body. (4) A thermocouple may be provided on the downstream side of the bar sealer.

  As the operation resumes, the polymerization end of the cylindrical film is sandwiched between the sealing surfaces of the bar sealer. Then, the heat of the bar sealer is absorbed by the polymerization end from the surface of the sealing surface, and the polymerization end is melted. However, the surface temperature of the sealing surface is lowered with this heat absorption. However, in the present invention, since the volume of the downstream part of the bar sealer is increased, a large amount of heat is stored in the part, and the heat is transmitted through the bar sealer and supplied to the seal surface side. Therefore, the lowering of the surface temperature of the bar sealer at the downstream portion is alleviated as compared with the upstream portion of the bar sealer. Therefore, the temperature of the seal surface of the bar sealer can be maintained at a value close to the target value (set value), and heat sealing can be stably performed on the polymerization end from the beginning of operation.

  Moreover, when a thermocouple is installed on the downstream side of the bar sealer as in the invention of (4), temperature control can be performed accurately. That is, as described above, on the upstream side of the bar sealer, the surface temperature of the bar sealer is reduced due to heat being taken away by the film running when the operation resumes, but the temperature change compared to the upstream side of the downstream side of the bar sealer Less is. For this reason, if a thermocouple is installed on the upstream side of the bar sealer, the temperature control of the bar sealer is performed according to the temperature change on the upstream side of the bar sealer, and the temperature on the upstream side of the bar sealer varies greatly. Therefore, it is difficult to perform stable temperature control. In addition, the actual temperature of the downstream side of the bar sealer is higher than the set temperature, which may cause poor appearance. Therefore, by installing a thermocouple on the downstream side of the bar sealer and performing temperature measurement in a portion where the temperature change is small, stable temperature control with little temperature variation can be performed.

  In the present invention, since the volume on the downstream side in the traveling direction is larger than the volume on the upstream side in the traveling direction of the cylindrical film of the bar sealer, the temperature decrease in the downstream part of the bar sealer is suppressed as much as possible immediately after the start of operation, Heat sealing can be stably performed with respect to the polymerization end of the tubular film.

  2 and 3 show a first preferred embodiment of the present invention. The pillow wrapping machine 10 on which the center seal device of this embodiment is mounted includes a wrapping machine main body 11, a film supply device 12 that continuously supplies a belt-like wrapping film to the wrapping machine main body 11, and a wrapping machine main body. 11 is provided on the upstream side of the packaging material supply device 14 for supplying the packaging material 13 to the packaging machine body 11 at predetermined intervals.

  The film supply device 12 links the output of a drive motor (not shown) (speed-controllable motor such as a servo motor) to the original roll 16 obtained by winding the belt-like film 15 into a roll. Supplying to the packaging machine body 11 at a constant speed while appropriately controlling the rotation speed. Although not shown, various rollers are arranged at predetermined positions from the original fabric roll 16 to the packaging machine body 11, and the belt-like film 15 fed out from the original fabric roll 16 is passed over the rollers. Then, it is guided to the packaging machine body 11 through a predetermined path. Of course, in the present invention, it is not always necessary to link the drive motor to the raw roll 16, and a feed roller may be provided on the transport path of the packaging film and pulled out.

  The package transporting and supplying device 14 includes a sprocket 17 (only the front in the traveling direction is shown in the figure) arranged at the front and rear, an endless chain 18 spanned over the plurality of sprockets 17, and a predetermined pitch on the endless chain 18. It is comprised by the several pushing finger | toe 19 attached for every. Thereby, when the pushing finger 19 hits the rear surface of the article 13 to be packaged, the article 13 also moves forward with the movement of the pushing finger 19.

  The packaging machine main body 11 includes a bag making device 20 that sets the supplied belt-like film 15 into a cylindrical film 21, a center seal device 25 disposed on the downstream side of the bag making device 20, and the center seal device 25. A belt conveyor 23 that conveys the tubular film 21, an end seal device 30 that is disposed downstream of the belt conveyor 23, and a carry-out conveyor 26 that is disposed downstream of the end seal device 30. It is equipped with.

  The bag-making device 20 allows the side film edges 15a of the belt-like film 15 to contact (polymerize) with each other by passing the belt-like film 15 continuously supplied from the film feeding device 12, and the tube that has become cylindrical. The bag is placed on the film 21. In addition, the articles to be packaged 13 that are sequentially supplied from the article to be packaged supply apparatus 14 to the packaging machine main body 11 are inserted into the bag making machine 20. Thereby, the article 13 to be packaged supplied to the bag making machine 20 is arranged in the cylindrical film 21 at predetermined intervals.

  The center seal device 25 seals the film polymerization end 21a of the tubular film 21 (a portion where the side edge portions 15a of the strip-shaped film 15 formed into a tubular shape are overlapped). As shown in FIG. 3, the center seal device 25 has a pair of bar sealers 31 disposed on both sides in the traveling direction of the tubular film 21, and the bar sealer 31 moves the film polymerization end 21 a of the tubular film 21 from both sides. Heat sealing is performed by sandwiching and heating. Details will be described later.

  The end seal device 30 seals and cuts the tubular film 21 in a direction orthogonal to the traveling direction, that is, in a transverse direction. The film part to be sealed / cut is a predetermined position between the front and back objects 13 to be packaged. Thereby, the head part of the cylindrical film 21 is isolate | separated from the subsequent by passing the end seal apparatus 30, and the package body 27 is manufactured.

  In the illustrated example, the end seal device 30 includes top sealers 30a and 30b that are vertically opposed to each other with the tubular film 21 interposed therebetween, and maintains a state in which the seal surfaces of the top sealers 30a and 30b are opposed to each other. It is a so-called box motion type device configured to revolve and move along a predetermined trajectory, but a top sealer is attached to each of a pair of upper and lower rotating shafts, and both top sealers are centered on the rotating shaft. There are various types such as rotating type.

  As described above, the center seal device 25 includes a pair of bar sealers 31 for sandwiching and heating the film polymerization end 21a of the tubular film 21 with a predetermined pressure. The opposed surfaces of the pair of bar sealers 31 are the seal surfaces 31a. In addition, the pair of bar sealers 31 is configured to approach and separate as shown in FIGS. 3A and 3B by a drive mechanism (not shown) as in the prior art. And as shown to Fig.3 (a), when both the bar sealers 31 approach mutually, a clearance gap is formed between the sealing surfaces 31a. This gap is slightly narrower than the thickness of the film polymerization end 21, and can be sandwiched at a predetermined pressure due to the difference. Further, in a state where the bar sealers 31 are separated from each other, a predetermined space K is formed between the seal surfaces 31a. By forming this space K, the cylindrical film 21 (film polymerization end 21a) can be easily inserted and set between the bar sealers 31. Since these configurations are the same as the conventional ones, a specific description for realizing them is omitted.

  Here, in the present embodiment, the thickness of the bar sealer 31 (distance: height from the seal surface 31a to the opposite surface on the opposite side) is set to the upstream portion 32 and the downstream portion in the flow direction of the tubular film 21. Different from 33. Specifically, the thickness h2 of the downstream portion 33 is increased (h2 = h1 * 2) as compared with the thickness h1 of the upstream portion 32. Thereby, the volume 33 of the downstream part becomes larger than the volume (per unit length) of the upstream part 32.

  Furthermore, in the present embodiment, a thermocouple 34 serving as a temperature sensor is installed near the carry-out side of the downstream portion 33. Accordingly, when the temperature detected by the thermocouple 34 is monitored and the heaters built in the bar sealer are energized and heated with the seal surfaces 31a of the two bar sealers 31 separated from each other, the seals are sealed after a predetermined period of time. The surface 31a is stabilized at the set temperature. At this time, almost the entire bar sealer 31 is maintained at the set temperature. Prior to heating the bar sealer 31 as described above, the film polymerization end 21a of the tubular film 21 is inserted and disposed in the space K between the seal surfaces 31a of the both bar sealers 31 as described above.

  In this state, the seal surfaces 31a of both the bar sealers 31 are brought close to each other, the film polymerization end 21a of the tubular film 21 is sandwiched between the both seal surfaces 31a, and the conveyance of the tubular film 21 is started (resumption of operation). Then, the heat of the bar sealer 31 is transmitted to the film polymerization end 21a through the seal surface 31a, and the film polymerization end 21a is heated and melted and fused. Along with this, the heat in the vicinity of the seal surface 31a of the bar sealer 21 is absorbed by the film polymerization end 21a side, and the surface temperature of the seal surface 31a decreases. Then, since a temperature gradient is generated inside the bar sealer 21, heat stored in a portion away from the seal surface 31 a to be uniform is transmitted to the seal surface 31 a side, and the degree of temperature decrease is suppressed. Therefore, since the downstream side portion 33 of the bar sealer 31 is thicker than the upstream side portion 32, the total amount of heat stored is also large, and the deterioration of the seal surface 31a is suppressed. That is, when the upstream portion 32 is set to be approximately the same as the thickness h1 of the conventional bar sealer, the surface temperature of the seal surface 31a is 5 from the target value at the beginning when the film polymerization end 21a of the tubular film 21 is sandwiched. Although the temperature is decreased by about ° C., the decrease in the surface temperature of the seal surface 31a of the downstream side portion 33 in which the thickness h2 is set to be about twice that of the upstream side portion can be suppressed to 2 to 3 ° C.

  Thereby, there is no problem of insufficient heating for the film polymerization end 21a at the beginning of operation, and heat sealing can be surely performed from the beginning. Of course, since the surface temperature of the seal surface 31a is controlled to be constant at the target value based on the output of the thermocouple 32, after a certain time has elapsed from the start of operation, the target temperature is stabilized and becomes cylindrical. Appropriate heat sealing can be performed on the film.

  At this time, since the entire bar sealer 31 is heated, the total volume increases as the thickness increases, and the amount of heat required to heat the bar sealer 31 in order to maintain the target value increases. That is, after the sealing surface 31a is stabilized, the portion of the downstream portion 33 that is separated from the sealing surface 31a becomes a portion that must be heated wastefully. However, in the present embodiment, since the thickness h1 of the upstream portion 32 is set thin, the amount of heat required to heat the upstream portion 32 can be smaller than that in the downstream portion 33. Therefore, the only part that needs to be heated more than necessary in a stable operation period after the start of operation is the outer part of the downstream part 33 (part away from the seal surface 31a). Compared to the case where the entire sealer 31 is uniformly thickened, the amount of heat required to heat the entire bar sealer 31 can be suppressed, and this is suitable for energy saving (eco).

  Furthermore, in this embodiment, the thermocouple 32 is provided on the downstream side (unloading side) of the bar sealer 31. Thereby, since the temperature of the seal | sticker surface 31a just before the film superposition | polymerization end 21a comes out of the bar sealer 31 can be measured, temperature control can be performed correctly. That is, if the thermocouple 34 is installed on the upstream side of the bar sealer 31, as described above, the upstream portion 32 of the bar sealer 31 heats the tubular film 21 (film polymerization end 21 a) that travels when the operation is resumed. As a result, the surface temperature of the seal surface 31a of the part is greatly reduced, and the amount of change is larger than the temperature change of the surface temperature of the seal surface 31a of the downstream part 33. Therefore, if the temperature control of the bar sealer 31 is performed in accordance with the temperature change of the upstream side portion 32 of the bar sealer 31, the temperature of the upstream side portion 32 of the bar sealer 31 varies greatly. ) Also increases, and it becomes difficult to overshoot until the temperature stabilizes to the target value, and to converge to the target value stably in a short time.

  Further, even after the stable state is reached, the upstream portion 32 of the bar sealer 31 carries in (enters) the non-heated tubular film 21 (film polymerization end 21a). The heat of the sealing surface 31a is taken away by the cylindrical film. On the contrary, in the downstream portion 33, the film polymerization end 21a of the tubular film 21 has already been heated up to that point, so that the amount of heat taken away by the seal surface 31a to the film polymerization end 21a side is small (almost no It can also be said). Therefore, when a thermocouple is installed in the upstream portion where heat is taken away by the tubular film 21 that has entered regularly, and the temperature is controlled based on the thermocouple, the temperature of the downstream portion 33 of the bar sealer 31 becomes the set temperature (target). Value), and the heating amount for the film polymerization end 21a of the tubular film 21 is increased on the carry-out side, which may result in poor appearance. Therefore, as in the present embodiment, the thermocouple 34 is installed on the downstream side of the bar sealer 31, and the temperature is measured in a portion where the temperature change is small, so that stable temperature control with little temperature variation can be performed.

  FIG. 4 shows a second embodiment of the present invention. The center seal device 25 of this embodiment has a rectangular auxiliary structure on the outer side (opposite to the seal surface) of the downstream portion 41b of the thin sticker (rectangular) sealer body 41 having the same thickness. The member 42 is connected. Thereby, as a whole bar sealer, compared with the thickness h1 of the upstream site | part 41a, the thickness h2 of the downstream site | part 41b (+ auxiliary member 42) can be thickened. Furthermore, the sealer main body 41 and the auxiliary member 42 are both made of metal and are in contact with each other so that heat can be mutually transmitted.

  As a result, the heat conduction in the bar sealer and the removal of heat to the tubular film 21 (film polymerization end 21a) are the same as in the first embodiment, and the film polymerization end 21a is reliably secured from the beginning of operation. The same operational effects as the first embodiment can be obtained, such as being able to be heat-sealed.

  Furthermore, in this embodiment, since the sealer main body 41 and the auxiliary member 42 are formed as separate members, the metal material constituting the sealer body 41 and the auxiliary member 42 may be formed of the same kind of metal such as iron, or may be formed of different metals. For example, since the auxiliary member 42 only needs to have a function of replenishing heat to the sealer body 41 (downstream part 41b) immediately after the start of operation, a metal having good thermal conductivity such as aluminum can be used. Since the sealer body 41 is required to heat the tubular film 21 (film polymerization end 21a) and pressurize with a certain force, a certain level of altitude is required, and a metal such as iron is used as before. Become. In this way, when the thermal conductivity is more aluminum, it can be heated to a desired temperature with a smaller amount of heat than iron, etc., so the heater is energized in a stable state after a certain time has elapsed since the start of operation. The amount can be suppressed. Aluminum or the like can easily dissipate heat, but there is no problem as long as heat can be supplied and supplemented to the downstream portion 41b only for a certain period immediately after the start of operation. Other configurations and operational effects are the same as those of the first embodiment.

It is a figure explaining a prior art example. It is a figure which shows an example of the pillow packaging machine which this invention mounts. It is a figure showing a 1st embodiment of a center seal device concerning the present invention. It is a figure which shows 2nd Embodiment of the center seal apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pillow packaging machine 11 Packaging machine main body 12 Film supply apparatus 13 Packaged article 14 Packaged article conveyance supply apparatus 21 Cylindrical film 21a Film superposition end 25 Center seal apparatus 30 End seal apparatus 31 Bar sealer 32 Upstream part 33 Downstream part 34 Thermocouple 41 Sealer body 41a Upstream part 41b Downstream part 42 Auxiliary member

Claims (4)

Means for forming a continuously supplied belt-like film into a cylindrical shape, a center sealing device for sealing the overlapping end of the cylindrical film formed in the cylindrical shape, and a downstream side of the center sealing device The center seal device used in an automatic packaging machine provided with an end seal device that performs sealing and cutting in the width direction of the tubular film,
A pair of rod-shaped bar sealers that sandwich the overlapping end from both sides,
A center seal device characterized in that the volume on the downstream side in the traveling direction is larger than the volume on the upstream side in the traveling direction of the tubular film of the bar sealer.   2. The center seal device according to claim 1, wherein the volume on the downstream side in the traveling direction is increased by changing the thickness from the seal surface to the opposite surface of the bar sealer.   3. The center seal device according to claim 1, wherein the bar sealer includes a rectangular parallelepiped sealer body and a metal auxiliary member connected to a downstream side surface of the sealer body.   The center seal device according to any one of claims 1 to 3, wherein a thermocouple is provided on a downstream side of the bar sealer.

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