Sealing bar and heat sealing device

Abstract

To provide a technique that accurately detects a temperature of a seal surface without being affected by a sealing condition or the like.SOLUTION: A rod-shaped seal bar including a seal surface having a length in a long side direction and a height in a short side direction includes a heater that is provided inside of a main body of the seal bar and extends in the long side of the main body to transfer heat to the seal surface, and a temperature sensor that is provided inside of the main body of the seal bar and is disposed at a position between the seal surface and the heater and a position in the vicinity of a center in a height direction of the seal surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a technique for sealing packaging materials and the like. [Background technology]

[0002] For example, in a packaging machine, a seal bar having a sealing surface for thermocompression is used to thermocompress (seal) packaging materials when forming packages such as candy bags. In order to obtain a good sealing condition at the thermocompression points of the packaging materials, it is preferable to directly detect and control the temperature of the sealing surface with a temperature sensor. However, if a temperature sensor is provided on the sealing surface for this purpose, the smoothness of the sealing surface decreases, which in turn adversely affects the sealing condition of the packaging materials.

[0003] Therefore, in the past, in temperature control of the seal surface, the temperature of the seal surface was not directly detected, but the temperature of a surface of the seal bar other than the seal surface was detected (for example, Patent Document 1). Alternatively, a temperature sensor was inserted into the seal bar from the side intersecting with the short side of the seal surface to detect the temperature inside the seal bar. Specifically, a heater was provided inside the seal bar extending in the extension direction of the seal bar, and the temperature sensor was inserted into the seal bar in the same direction as the extension direction of the heater. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5423078 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the temperature is detected at a position different from the position on the seal surface, the difference between the detected temperature and the actual temperature of the seal surface varies depending on the sealing conditions (seal bar structure, sealing (thermocompression) repetition speed, ambient temperature, etc.) For this reason, simply setting an offset value to correct the temperature detected by the temperature sensor does not allow for proper temperature control of the seal surface.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a technique for detecting the temperature of a seal surface with high accuracy without being affected by sealing conditions, etc. [Means for solving the problem]

[0007] The present invention relates to, for example, , long The seal bar is a rod-shaped seal bar having a seal surface with long and short sides and an end surface, and is provided with a heater that is provided inside the body of the seal bar and extends in the long side direction of the body to transfer heat to the seal surface, and a temperature sensor that is provided inside the body of the seal bar and is located between the seal surface and the heater, and is also located between the center line of the seal surface in the short side direction and an auxiliary line that bisects the area between the center line and the end surface. This configuration According to The temperature of the seal surface can be detected with high accuracy without being affected by sealing conditions, etc.

[0008] Also, for example, A rod-shaped seal bar having a seal surface with long and short sides and an end surface, a heater provided inside the body of the seal bar and extending in the long side direction of the body to transfer heat to the seal surface, and a temperature sensor provided inside the body of the seal bar at a position that is closer to the seal surface than the distance from the seal surface to the heater, and that is located between the center line of the seal surface in the short side direction and an auxiliary line that bisects the area between the center line and the end surface, Even with this configuration, the temperature of the seal surface can be detected with high accuracy without being affected by the sealing conditions, etc.

[0009] Also, for example, A rod-shaped seal bar having a seal surface having long and short sides and an end surface, comprising: a heater provided inside the body of the seal bar and extending in the long side direction of the body to transfer heat to the seal surface; and a temperature sensor provided inside the body of the seal bar and positioned such that the distance from the end surface in a direction along the seal surface is 1 / 4 or more of the length in a direction perpendicular to the long side direction of the seal surface and is 1 / 2 or less of the length in the direction perpendicular to the long side direction of the seal surface; Even with this configuration, the temperature of the seal surface can be detected with high accuracy without being affected by the sealing conditions, etc. Effect of the Invention

[0010] According to the present invention, it is possible to detect the temperature of the seal surface with high accuracy, without being affected by the sealing conditions and the like. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view conceptually showing a heat sealing device according to a first embodiment. [Diagram 2] FIG. 2 is a side view conceptually showing a heat sealing device. [Diagram 3] FIG. 2A is a plan view of a seal bar provided in a heat sealing device, viewed from the sealing surface side, and FIG. 2B is a plan view of the seal bar, viewed from the upper end surface side. [Figure 4] FIG. 1 is a graph of data obtained by the present inventors. [Diagram 5] FIG. 2 is a block diagram conceptually showing the configuration of a heat sealing device. [Figure 6] FIG. 11 is a side view conceptually showing a heat sealing device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment in which the present invention is applied to a heat sealing device provided in a packaging machine or the like will be specifically described with reference to the drawings.

[0013] [1] First embodiment 1 and 2 are respectively a perspective view and a side view conceptually showing a heat sealing device according to the first embodiment. As shown in Fig. 1 and Fig. 2, the heat sealing device has a pair of seal bars 1 arranged opposite each other, and a seal surface 11a is formed on each of the opposing surfaces 111. The pair of seal bars 1, in a heated state, clamp and press the packaging material passing between them to thermocompress the packaging material and form a package such as a confectionery bag. In Fig. 2, the pair of seal bars 1 are symmetrical, and only the seal bar 1 on the right side is labeled with a reference number.

[0014] Specifically, each seal bar 1 has a rod-shaped main body 11 having a sealing surface 11a, a cutting blade 12 used to cut the packaging material at the thermocompression bonding location, a heater 13, and a temperature sensor 14.

[0015] The cutting blade 12 has a flat blade shape, and is provided on the main body 11 with the width direction of the cutting edge 12a coinciding with the extending direction D1 (see FIG. 1) of the main body 11. More specifically, a groove 11b capable of accommodating the cutting blade 12 is formed on the opposing surface 111, and the cutting blade 12 is provided so as to be capable of reciprocating between a protruding position where the cutting edge 12a protrudes from the opposing surface 111, and a retracted position where the cutting edge 12a is accommodated in the groove 11b. The reciprocating movement of the cutting blade 12 is performed by a driving unit 2 (see FIG. 5) provided in the heat sealing device.

[0016] FIG. 3(A) is a plan view of the seal bar 1 from the sealing surface 11a (opposing surface 111). As shown in FIG. 3(A), the opposing surface 111 has a sealing surface 11a on both sides (upper and lower sides in this embodiment) of the groove 11b. Each sealing surface 11a has a rectangular shape extending in the extending direction D1 of the main body 11. As shown in FIG. 2 and FIG. 3(A), the main body 11 of the seal bar 1 further has an upper end surface 112 intersecting with the upper side 11c (upper long side) of the upper sealing surface 11a and a lower end surface 113 intersecting with the lower side 11d (lower long side) of the lower sealing surface 11a. In this embodiment, the upper end surface 112 and the lower end surface 113 are formed approximately perpendicular to the sealing surface 11a (opposing surface 111).

[0017] The heater 13 has a rod shape thinner than the main body 11 of the seal bar 1, and is provided inside the main body 11 with its extending direction coinciding with the extending direction D1 of the main body 11. Specifically, the heaters 13 are provided at positions overlapping with the two upper and lower sealing surfaces 11a, one each, in the plan view shown in FIG.

[0018] FIG. 3(B) is a plan view of the seal bar 1 from the upper end surface 112 side. As shown in FIG. 3(B), the upper end surface 112 is provided with a perforation 112a that leads to the inside of the body 11 of the seal bar 1. Specifically, the perforation 112a is formed so as to reach a position between the seal surface 11a and the heater 13 corresponding thereto (see FIG. 2 and FIG. 3(A)). More specifically, the perforation 112a extends in a direction D2 perpendicular to the extension direction D1 of the body 11 and along the seal surface 11a so as to reach such a position. In this embodiment, the perforation 112a extends in a direction perpendicular to the upper end surface 112. In this embodiment, the lower end surface 113 is also provided with a perforation 112a that leads to the inside of the body 11 of the seal bar 1, similar to the perforation 112a provided in the upper end surface 112.

[0019] 3(A), the temperature sensors 14 are sensors such as thermocouples, and are inserted one by one into perforations 112a provided in the upper end face 112 and the lower end face 113, so that their tips reach predetermined positions inside the main body 11. That is, the temperature sensors 14 are inserted into the main body 11 from each of the upper end face 112 and the lower end face 113. As a result, inside the main body 11, each temperature sensor 14 is provided at a position between the seal surface 11a, which is the object of temperature detection by the temperature sensor 14, and the heater 13 corresponding to it.

[0020] With such a heat sealing device, when heat is transferred from the heater 13 to the sealing surface 11a, the heat passes around the temperature sensor 14. Therefore, the temperature detected by the temperature sensor 14 is likely to correspond to the actual temperature of the sealing surface 11a without being affected by the sealing conditions (seal bar structure, sealing (thermocompression) repetition speed, ambient temperature, etc.). As an example, the ratio of the heat transferred to the temperature sensor 14 and the heat transferred to the sealing surface 11a is likely to be almost constant without being affected by the sealing conditions, etc. Therefore, with the above heat sealing device, it becomes possible to accurately detect the temperature of the sealing surface 11a without being affected by the sealing conditions, etc.

[0021] From the viewpoint of enabling such temperature detection of the seal surface 11a, the inventors obtained various data, which will be described later, and based on the data, optimized the position of the temperature sensor 14 inside the body 11 of the seal bar 1 and the size of the temperature sensor 14. Figure 4 is a graph of the data obtained by the inventors.

[0022] The inventors prepared temperature sensors 14 with diameters dm of 1 mm and dm of 1.6 mm. By changing the positions of the perforations 112a into which they were inserted, the temperature sensors 14 with diameters dm of 1 mm were placed at positions where the distances L1 (see FIG. 2) from the seal surface 11a in the direction perpendicular to the seal surface 11a were 1 mm, 3 mm, and 5 mm, respectively, and the temperature sensors 14 with diameters dm of 1.6 mm were placed at positions where the distances L1 were 3 mm and 5 mm, respectively. For comparison with these, a conventional temperature sensor (diameter 3 mm) was inserted into the seal bar from the side intersecting with the short side of the seal surface 11a, and the insertion position was changed to place the conventional temperature sensor at positions where the distances L1 were 1 mm, 3 mm, and 5 mm, respectively. Then, during sealing, the temperature at each position was measured by each temperature sensor, and the actual temperature of the seal surface 11a was measured by another temperature sensor. FIG. 4 shows, in a graph, the relationship between the distance L1 from the seal surface 11a and the temperature difference ΔT between the actual temperature of the seal surface 11a and each temperature sensor.

[0023] From the graph shown in Fig. 4, the inventors have found the optimization conditions for the position and size of the temperature sensor 14. Specifically, in the case of a conventional temperature sensor, the temperature difference ΔT is about 10°C regardless of the distance L1 from the sealing surface 11a, whereas with the temperature sensor 14 and its arrangement proposed by the inventors, the temperature difference ΔT is 4°C or less. Therefore, the inventors have found the following conditions, with the temperature difference ΔT being 4°C or less as the optimization condition.

[0024] As a first condition, it is preferable that the temperature sensor 14 is disposed at a position where the distance L1 (see FIG. 2) from the sealing surface 11a in the direction perpendicular to the sealing surface 11a is 5 mm or less. More preferably, the temperature difference ΔT is 2° C. or less, and in this case, for a temperature sensor 14 with a diameter dm of 1.6 mm, the condition is that the temperature sensor 14 is disposed at a position where the distance L1 is 3 mm or less. Note that, for a temperature sensor 14 with a diameter dm of 1 mm, the condition is that the temperature sensor 14 is disposed at a position where the distance L1 is 5 mm or less, as in the case where the optimization condition is that the temperature difference ΔT is 4° C. or less.

[0025] As a second condition, it is preferable that the diameter dm of the temperature sensor 14 is less than 3 mm.

[0026] Although not shown in FIG. 4, the present inventors have also found the following condition for detecting the temperature of the seal surface 11a with high accuracy.

[0027] As a third condition, it is preferable that the temperature sensor 14 is disposed at a position where the distance L2 (see FIG. 2) from the upper end face 112 (or the lower end face 113) in the direction D2 perpendicular to the extending direction D1 of the main body 11 and along the sealing surface 11a is equal to or greater than the insertion depth dp (L2≧dp) determined by the diameter dm of the temperature sensor 14. As an example, the insertion depth dp can be six times the diameter dm.

[0028] As a fourth condition, in a plan view (see FIG. 3(A)) from the side of the seal surface 11a (opposing surface 111) of the main body 11 of the seal bar 1, it is preferable that the temperature sensor 14 is disposed at a position between a center line m1 and an auxiliary line m2 that are approximately parallel to the long side of the seal surface 11a that is the target of temperature detection (in this embodiment, the upper side 11c of the upper seal surface 11a and the lower side 11d of the lower seal surface 11a). Here, the center line m1 is an imaginary straight line that bisects each seal surface 11a, and the auxiliary line m2 is an imaginary straight line that further bisects the area between each long side of each seal surface 11a and the center line m1.

[0029] As a fifth condition, when viewed in a plan view from the sealing surface 11a (opposing surface 111) side relative to the main body 11 of the sealing bar 1, it is preferable that the temperature sensor 14 is arranged within the area (sealing execution area) of the sealing surface 11a that abuts against the object to be sealed, such as packaging material.

[0030] Fig. 5 is a block diagram conceptually showing the configuration of a heat sealing device. As shown in Fig. 5, the heat sealing device further includes a drive unit 2 and a control unit 3 in addition to the pair of seal bars 1 described above. The drive unit 2 is a drive mechanism that realizes operations such as opening and closing operations of the seal bars 1 when thermocompressing a packaging material, and cutting operations of the cutter blades 12 when cutting the packaging material (movement from a retreated position to a protruding position).

[0031] The control unit 3 controls at least the drive unit 2 and the heater 13. Specifically, the control unit 3 controls the drive unit 2 in accordance with a predetermined operation program, thereby causing the drive unit 2 to repeatedly execute a sealing operation for thermocompression bonding the packaging material. The control unit 3 also controls the heater 13 based on the detected temperature T of the temperature sensor 14, thereby bringing the temperature of the sealing surface 11a to a desired temperature.

[0032] As described above, according to the heat sealing device of this embodiment, the temperature detected by the temperature sensor 14 is likely to correspond to the actual temperature of the sealing surface 11a without being affected by the sealing conditions, etc. Therefore, the temperature change on the sealing surface 11a is likely to be reflected in the detected temperature T by the temperature sensor 14, and therefore, the temperature change on the sealing surface 11a can be detected with high accuracy. Therefore, the temperature change on the sealing surface 11a is likely to be reflected in the control of the heater 13 based on the detected temperature T by the temperature sensor 14, and as a result, the temperature of the sealing surface 11a can be controlled with high accuracy.

[0033] [2] Second embodiment Fig. 6 is a side view conceptually showing a heat sealing device according to the second embodiment. As shown in Fig. 6, in each seal bar 1, the upper end surface 112 and the lower end surface 113 may be formed to be inclined with respect to the seal surface 11a (opposing surface 111). In this case, the perforation 112a is provided in each of the inclined upper end surface 112 and the lower end surface 113, and the distance L2 is the distance in the direction D2 from the opening position of the perforation 112a in each of the upper end surface 112 and the lower end surface 113.

[0034] [3] Other embodiments In the above-mentioned heat sealing device, the temperature sensor 14 is not limited to being provided corresponding to each of the upper seal surface 11a and the lower seal surface 11a, but may be provided corresponding to only one of the seal surfaces 11a. Also, the number of temperature sensors 14 provided corresponding to each seal surface 11a is not limited to one, and may be multiple.

[0035] The seal bar 1 is not limited to one equipped with a cutting blade 12, but can be modified into various configurations in which at least one seal surface 11a is formed. Furthermore, the above-mentioned heat sealing device is not limited to one equipped with a pair of seal bars 1, but may be one equipped with only one seal bar 1. Furthermore, the heat sealing device is not limited to one that performs thermocompression bonding (sealing) on ​​packaging materials, but can also be used in cases such as vacuum sealing electronic devices with exterior members. [Explanation of symbols]

[0036] 1 Seal bar 2 Drive unit 3. Control Unit 11 Main unit 11a Sealing surface 11b Groove 11c Top 11d Bottom 12 Cutting blade 12a cutting edge 13 Heater 14 Temperature Sensor 111 Opposite surface 112 Upper end surface 112a perforation Lower end surface of 113 D1 extending direction D2 direction dm diameter dp insertion depth L1, L2 distances m1 center line m2 auxiliary line T detected temperature

Claims

1. A rod-shaped integral member having a sealing surface with long and short sides and an end surface; a heater provided inside the rod-shaped member, extending in a direction parallel to a long side of the rod-shaped member, and configured to transfer heat to the sealing surface; a temperature sensor provided inside the rod-shaped member, the temperature sensor being disposed between the seal surface and the heater and between a center line in a short side direction of the seal surface and an auxiliary line that bisects an area between the center line and the end surface; A seal bar equipped with

2. A rod-shaped integral member having a sealing surface with long and short sides and an end surface; a heater provided inside the rod-shaped member, extending in a direction parallel to a long side of the rod-shaped member, and configured to transfer heat to the sealing surface; a temperature sensor provided inside the rod-shaped member, the temperature sensor being disposed at a position that is a distance from the sealing surface that is shorter than a distance from the sealing surface to the heater, and at a position between a center line in a short side direction of the sealing surface and an auxiliary line that bisects an area between the center line and the end surface; A seal bar equipped with

3. A rod-shaped integral member having a sealing surface with long and short sides and an end surface; a heater provided inside the rod-shaped member, extending in a direction parallel to a long side of the rod-shaped member, and configured to transfer heat to the sealing surface; a temperature sensor provided inside the rod-shaped member, the temperature sensor being disposed at a position whose distance from the end face in a direction along the seal surface is between ¼ of the length of the seal surface in a direction perpendicular to the long side direction and ½ of the length of the seal surface in a direction perpendicular to the long side direction; A seal bar equipped with

4. A rod-shaped integral member having a sealing surface with long and short sides and an end surface; a heater provided inside the rod-shaped member, extending in a direction parallel to a long side of the rod-shaped member, and configured to transfer heat to the sealing surface; a temperature sensor provided inside the rod-shaped member, the temperature sensor being located closer to the sealing surface than the heater and at a position between ¼ and ½ of the size of the rod-shaped member in a direction perpendicular to the long side direction; A seal bar equipped with

5. The seal bar according to any one of claims 1 to 4, wherein the distance from the end face at which the temperature sensor is disposed is six times or more the diameter of the temperature sensor.

6. The end faces are upper and lower end faces extending in the same direction as the extension direction of the sealing surface, The seal bar according to any one of claims 1 to 5, wherein the temperature sensor is inserted from at least one of the upper end surface or the lower end surface.

7. A heat sealing device comprising a pair of sealing bars described in any one of claims 1 to 6.

8. A seal bar according to any one of claims 1 to 6, a control unit that controls the heater based on a temperature detected by the temperature sensor; A heat sealing device comprising:

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