JP3411600B2 - Heat sealing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sealing apparatus for heat-sealing a hot-melt resin layer to a film material, a sheet material, etc. having a hot-melt resin layer. However, the present invention relates to the pressing structure of the heat seal roll. In particular, the present invention makes it possible to always perform uniform heat sealing over the entire length of the lateral seal portion of the bag, and at the same time, to sufficiently uniform the heat seal strength of each horizontal seal portion located at a distance from each other. The present invention relates to a heat sealing device for a bag making machine. 2. Description of the Related Art As a known heat sealing apparatus applied to an automatic filling bag making machine, there is one disclosed by the applicant in Japanese Patent Application Laid-Open No. 1-188328, for example. [0003] This prior art will be described with reference to an example of a horizontal seal roll based on FIG. 3. In addition to providing two pairs of rolls 32 and 33 which are arranged in parallel close to each other and driven to rotate in opposite directions to each other, Each roll 32, 33
In the place where the heat sealing blades 34, 35 having a circumferential arc surface extending in the length direction thereof are provided, two rolls 32, 33 of the respective rolls 32, 33 are spaced apart in the axial direction, Position regulating flanges that contact each other on the peripheral surface 36, 37
And the arcuate surfaces of the respective heat sealing blades 34, 35 are located somewhat radially inward of the peripheral surfaces of the position regulating flanges 36, 37. In such a heat sealing apparatus, the positions of the pair of rolls 32, 33 which are close to each other are specified by the abutment of the respective position regulating flanges 36, 37,
A necessary gap for heat sealing of a film material, a sheet material, or the like is always ensured between the heat sealing blades of the respective rolls that cooperate with each other, so that proper heat sealing can be realized. [0005] Incidentally, in such a heat seal roll, for example, a roll 33 as a fixed roll and a roll 32 as a movable roll are provided.
Is pressed with a force of (F + F =) 2F as shown in the figure.
A horizontal sealing portion H extending over the entire width of the film material W folded in the width direction at intervals in the length direction.
When forming S, each heat seal blade 34, 35
The film material W is intermittently interposed, so that the movable roll 32 is moved away from the fixed roll 33 in response to the impact in the direction opposite to the pressing force 2F each time the film material W is sandwiched. Is performed. At this time, if the amount of backward displacement of the position restricting flange 36 shown on the left side of the drawing and the position restricting flange 36 shown on the right side of the roll 32 is still the same in accordance with the sandwiching thickness, it is acceptable. For example, if the roll 32 is displaced in parallel over its entire length by an amount corresponding to the sandwiching thickness, it can be said that the horizontal seal portion HS is heat-sealed sufficiently uniformly over its entire length. However, in practice, in the context of the required bag width, the heat sealing blades 34, 35 hardly contribute to the heat sealing over their entire length, and these heat sealing blades 34, 35 As illustrated by the imaginary line in the drawing, the film material W is horizontally sealed only at a position deviated to the left ends of the rolls 32 and 33. Moreover,
Since the center of mass of the movable roll 32 including the rotary drive system and the like is not necessarily located at the center of the roll in the longitudinal direction, the heat seal blades 34 and 35 are used for the film material W.
When the roll 32 is sandwiched, the retreating force acting on the roll 32 (hereinafter referred to as "reaction force") will be different from each other at the left and right end portions of the roll 32. At a line speed where the running speed of the material W exceeds 5 m / min, the right and left roll ends vibrate in different modes due to the repetitive action of the reaction force on the roll 32. hand,
There is a large difference between the amount of retraction of the left end of the roll and the amount of retraction of the right end.In addition, due to vibration considered as self-excited vibration, the amount of displacement of each of the left and right ends is reduced by the heat seal blade. It may change greatly depending on the circumferential position. Therefore, the sealing state of the horizontal seal portion HS, and eventually,
It has been extremely difficult not only to make the seal strength sufficiently uniform over its entire length, but also to make the seal strength of each horizontal seal portion HS spaced apart uniform. FIG. 4 is a graph showing this, and FIG.
Each heat seal blade 3 of the horizontal seal roll shown in
The number of 4 and 35 is 4 each, the diameter of the arc passing through the surface of each heat seal blade 34 and 35 is 90mmφ, and the length of each heat seal blade is 150mm.
In the heat sealing device with the interval of 34, 35 set to 50μ,
EV with a thickness of 30μ on a polyester film with a thickness of 16μ
The full Irumu material W by laminating A ing, while folded in two from the center portion in the width direction, in the case of forming a transverse seal portion HS put a gap in the longitudinal direction, each of the movable roll 32 When the running speed of the film material W is 6 m / min, 12 m / min and 24 m / min, the retreat displacement of each bearing block (not shown) supporting the shaft end portion of
The results are as shown in FIGS. 4 (a), (b) and (c), respectively.
In this case, the left end of the movable roll 32 was connected to the drive system, and the pressing force 2F of the roll 32 was 100 kgf. The upper graph in FIG. 4 shows the displacement on the left end side, that is, the sandwiching side of the film material W, and the lower graph shows the displacement on the right end side, with the horizontal axis representing the time axis. The base line is that both rolls 32,
33 indicates the contact position of the peripheral surface of each of the position regulating flanges 36 and 37, and the positive direction of the vertical axis indicates the amount of backward displacement. Note in the figure, No. 1 to No.. 4 marked parts show the retreating position when the action of which corresponds to the number assigned to each of the heat seal blades 34, 35 which cooperate with each other. According to these graphs, the film material W
Regardless of the running speed of the film material W, the amount of retreat displacement of the roll end portion when the respective heat seal blades 34 and 35 are acting tends to be closer to the right end side than the left end side which is the sandwiching side of the film material W. According to this, the pressing force of the heat seal blade against the film material W decreases at the right end of the roll 32, that is, the heat seal strength may be insufficient at the right end. I understand that there is. Here, the heat seal blades 34, No. 1 to No.
Retreating amount differs during the action of 35, therefore, the seal strength of each of the lateral seal portion HS of mutually spaced also a high possibility that a non-uniform. [0012] That is, according to the graph, you can have contact to the right or left end portion, No. 1 and No. retreating amount are both greater during the action of the third heat seal blades, and almost the same value On the other hand, the displacement amount during the operation of No. 2 and No. 4 becomes smaller than those displacement amounts, and especially on the right end side, the mutual displacement amount between the No. 2 portion and the No. 4 portion Are greatly different from each other, and in the portions of No. 1 and No. 3, the amount of retreat displacement is too large,
It is conceivable that the roll pressing force on the film material W is insufficient. Conversely, in the No. 2 portion on the right end side, the pressing force on the film material W is too large, and the film material W is thermally melted. It is possible that most of the resin has been displaced. In addition, although the retreat displacement amount of the No. 2 part on the left end part is similar to that of the No. 4 part, the peak of the retreat displacement does not occur, and
Since it can be said that 32 is in the middle of forward displacement, it is difficult to determine whether the pressing force of the film material W at this portion is excessive or insufficient. Here, the specific displacements of the left end portion and the right end portion from the reference line at respective speeds are as shown in Table 1. [Table 1] According to this, it is recognized that the retreat displacement amount of the right end portion is almost two to three times the displacement amount of the left end portion at each speed except for the No. 2 portion. The present invention has been made as a result of studying to solve such a problem in the prior art, and an object of the present invention is to provide a movable roll main body with left and right end portions, respectively. By making the amount of retreat displacement substantially equal, and also making the amount of retreat displacement of each heat seal blade substantially uniform, the sealing strength of one horizontal seal portion is sufficiently uniform over its entire length. It is another object of the present invention to provide a heat sealing device that can make the sealing state of each horizontal sealing portion located at an interval sufficiently uniform. SUMMARY OF THE INVENTION The present invention particularly relates to the formation of a horizontal seal portion, in which respective heat seals provided on a movable roll side and a fixed side roll body and cooperating with each other are provided. In contrast to the retraction displacement of the movable-side roll body portion caused by the impact force acting on those heat-sealing blades by sandwiching the film material between the blades, the movable-side roll body portion receives the impact force far more. Is applied in advance, and the repulsive force is reduced at a specific rate according to the increase in the gap between the heat sealing blades and, consequently, the amount of retraction displacement of the roll body portion, so that the impact force By sufficiently mitigating the effect on the roll body, the movable roll body is made substantially parallel, in other words, the left and right end portions thereof Can be evenly displaced backwards, and
It is possible to effectively remove vibration components considered to be caused by self-excited vibration and the like, and to make each of the peak values of the retreat displacement amount at the time of the action of each heat sealing blade cooperating with each other substantially uniform. It was made based on the knowledge of. That is, the heat sealing apparatus according to the present invention comprises a pair of fixed and movable roll main bodies which are driven in pairs in two opposite directions and which are rotatably driven in opposite directions. Providing a heat seal blade extending in their longitudinal or circumferential direction and having a circumferential arcuate surface, and preferably at axially spaced locations on each roll body portion,
At the place where the position regulating flanges that come into contact with each other on the peripheral surface are provided, the movable roll body is constantly biased toward the fixed roll body with a constant force, for example, a constant force of about 200 to 500 kgf. While the pressing means is provided, an elastic means for pushing back the movable-side roll main body part in a direction away from the fixed-side roll main body part is arranged, and the pushing back force of this elastic means is balanced with the urging force of the elastic means. For the increase of the roll gap from the state,
It is to be reduced within the range of 8 kgf. In this heat sealing apparatus, for example, the roll body portion on the movable side is kept at a constant 300k by pressing means.
While pressing against the fixed-side roll body portion with the force of gf, the push-back force of the elastic means under the mutual contact state of the position regulating flanges provided on the respective roll body portions is also pressed. When the pressure is balanced, the movable roll main body portion is supported with substantially no external force. Here, assuming that the film material is sandwiched between the heat seal blades of the two roll main bodies, the movable roll main body is displaced backward by, for example, 100 μm, and the pushing back force of the elastic means is reduced by 50 kgf. The static balancing formula acting on the movable roll main body at the time is as follows: pressing force (300 kgf) = return force (250 kgf) + force due to pinching of film material (50 kgf). Power, ie
The impact reaction force acting on the heat sealing blade is sufficiently absorbed by the reduction of the repulsion force, and the repulsion force has a magnitude five times the impact reaction force. For this reason, it can be said that the retraction displacement of each end portion of the roll body portion here is performed under the control of a large pushback reaction force, rather than by an impact reaction force, and therefore, the heat sealing blade However, even if the film material is sandwiched only at one end portion, each end portion of the roll body portion is evenly affected by the impact reaction force generated by the action portion, and is hardly affected by the impact reaction force generated thereby. As a result, the horizontal seal portion is heat-sealed with substantially uniform strength over its entire length. In addition, here, as shown by the above-mentioned balancing type, it is possible to sufficiently absorb the generated impact reaction force with a large push-back force, and to make the movable roll main body part other than the impact reaction force. Because the bone mass system is so rigid that it can ignore the effect of small external forces,
Vibration components on the non-side due to self-excited vibration and other factors can be almost completely removed.Therefore, when the respective heat seal blades cooperate, the amount of retreat displacement of the movable-side roll main body part is excessive or insufficient. The heat seal strength of each of the spaced horizontal seal portions can also be made substantially uniform as a uniform amount without any gaps. Since the heat seal device operates as described above, the magnitude of the impact reaction force can be adjusted without adjusting the pressing force of the movable roll main body, in other words, the film material or sheet can be used. Regardless of the thickness of the material, appropriate heat sealing can always be performed. By the way, in this apparatus, the pushing back force of the elastic means is reduced in the range of 2 to 8 kgf per 10 μm, if it is less than 2 kgf, especially in the horizontal seal portion, the heat sealing blade, the film material or the sheet. It is based on the experience that it is empirically recognized that if the film or sheet material exceeds 8 kgf at the point of contact with the material, the heat seal blade will fail due to insufficient pressing force when the weight exceeds 8 kgf. It is. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing one embodiment of the present invention.
1A is a schematic plan view of the device, and FIG. 1B is a schematic side view of the device. [0026] Here, while the bearing supported by the respective axial end portions of the stationary side roll body 1 bearing block 2, and fixed their respective bearing block 2 to the housing 3 of the automatic filling bag-making machine, also, One end of the fixed-side roll body 1 is beveled gear 4
Through a rotary driving means (not shown). Here, the movable-side roll main body 5 is disposed in parallel with the fixed-side roll main body 1, and the bearing blocks 6 provided at the respective shaft end portions of the movable-side roll main body 5 are replaced with the bearing blocks 6. The movable roll body 5 is provided at one end of the movable roll body 5 by a frame member 7 protruding from the base 2 so as to be slidable in a direction approaching and away from the fixed roll body 1. The driven gear 8 is meshed with a drive gear 9 provided on the fixed-side roll main body 1. According to such a configuration, the roll body portions 1 and 5 can be rotated in opposite directions to each other based on the operation of the rotation driving means (not shown).
The movable-side roll main body portion 5 can be translated in a direction approaching the fixed-side roll main body portion 1 and in a direction opposite thereto in a slight distance based on the action of an external force thereon. Further, each of the roll body portions 1 and 5 is also provided with a circumferentially spaced and extending lengthwise surface, as described in the prior art, with a circumferential arcuate surface. Four heat sealing blades 10 and 11 are provided, and each position regulating flange 1 which is located with a gap in the axial direction and is in contact with each other on each peripheral surface.
2 and 13 are provided, wherein at least one arcuate surface of the heat seal blades 10 and 11 is positioned somewhat radially inward from the peripheral surfaces of the position regulating flanges 12 and 13. According to such a configuration, by rotating the roll body portions 1 and 5 in a state where the respective position regulating flanges 12 and 13 are in contact with their peripheral surfaces, heat seals cooperating with each other are formed. For example, a constant gap is always ensured between the blades for sandwiching the film material. By the way, the position regulating flanges 12, 13 are provided from the roll body portions 1, 5.
In this case, it is possible to secure a predetermined gap between the heat seal blades by specifying the distance between the respective bearing blocks 2 and 6. In addition, in this example, the pressing means 14 which constantly urges each bearing block 6 of the movable-side roll main body portion 5 with a constant force toward the fixed-side roll main body portion 1.
Are disposed between each of the bearing blocks 6 and the frame member 7, while the elastic means 15 for pushing the bearing blocks 6 away from the fixed-side roll body portion 1 is provided by the respective roll body portions 1. , 5 between the bearing blocks. Here, the pushing back force of each elastic means 15 is appropriately balanced with the force and the urging force of each pressing means 14,
For example, it is selected such that the peripheral surfaces of the respective position regulating flanges 12 and 13 just come into contact with each other and the contact surface pressure is reduced in the range of 1 to 4 kgf per 10 μm with respect to the increase of the roll gap from the state of zero. Note that this reduction ratio is determined by two elastic means.
In the case of No. 15, the range is 2 to 8 kgf per 10 μm. More specifically, for example, the movable-side roll main body portion 5 is fixed to the fixed-side roll main body portion by a total of 300 kgf by two pressing means 14 which can be a combined body of a spring and an air cylinder. When pressing to the side, the pushing back force of the two elastic means 15 is 300 kgf at the contact position of the position regulating flanges 12 and 13, and when the flanges 12 and 13 are separated by 10 μm, the pushing force is in the range of 292 to 298 kgf. When the distance is 100 μm, the range is 220 to 280 kgf . According to the heat sealing apparatus constructed as described above, in particular, as described above, the film material or the like is pinched between the heat sealing blades by the action of the large repulsive force of the elastic means 15. Thus, the effect of the impact reaction force acting on the movable roll main body portion can be extremely effectively removed, and the heat sealing state of the horizontal seal portion can be made sufficiently uniform over its entire length. In addition, the rigidity of the spring-mass system of the movable-side roll main body portion is increased, unnecessary vibration components are removed, and the heat sealing state of each of the spaced horizontal seal portions can also be made sufficiently uniform. . In addition, according to this device, as the thickness of the film material or the like sandwiched between the heat sealing blades increases, the sandwiching force acting on the film material itself increases, so that the film material For a slight change in thickness, proper heat sealing can always be performed without having to adjust the pressing force of the movable roll main body. Therefore, the present invention is extremely useful when applied not only to the horizontal sealing device but also to the vertical sealing device. FIG. 2 shows the amount of retreat displacement of the movable roll body 5 of the apparatus shown in FIG. 1 when the running speed of the film material is 6 m / min, 12 m / min and 24 m / min. 5 is a graph similar to FIG. FIG.
The temperature of the heat seal blade is 23 ° C in the place shown in Fig.
In that Here, the respective retreat displacement amounts of the left end portion and the right end portion, which are the sandwiching sides of the film material, were measured, and the results were as shown in Table 2. [Table 2] According to Table 2, the difference in the amount of backward displacement between the left and right side portions is much smaller than that of the prior art, and the amount of backward displacement in each of Nos. It is evident that the variation in volume is effectively reduced, especially in the right-hand end part, and it can be seen that these become more pronounced with increasing speed. The reason why the maximum variation of the displacement amount of each of the left end portions No. 1 to No. 4 is larger than that of the prior art is that the position regulating flanges provided on the roll body portions 1 and 5 are different. 1
It is considered that there is a cause in the processing accuracy of 2, 13. As described above, according to the present invention, the heat sealing state of the horizontal sealing portion can be made sufficiently uniform over its entire length mainly based on the action of the elastic means. In addition, the heat sealing state of each of the horizontal sealing portions located at an interval from each other can be made substantially uniform. And further, even for changes in the thickness of film members and other heat sealing members,
The clamping force acting on it can be adjusted automatically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an embodiment of the present invention. FIG. 2 is a graph showing a retracted position of a movable-side roll main body. FIG. 3 is a diagram showing a conventional technique. FIG. 4 is a graph showing the amount of retraction displacement of a movable roll according to the related art. [Description of Signs] 1 Fixed-side roll main body part 2, 6 Bearing block 3 Housing 5 Movable-side roll main body part 7 Frame member 10, 11 Heat seal blade 12, 13 Position regulating flange 14 Pressing means 15 Elastic means

Claims (1)

(57) [Claims 1] A pair of two roll bodies, fixed and movable roll body parts that are driven to rotate in opposite directions to each other, and provided on each of these roll body parts. A heat-seal blade extending in the longitudinal direction or circumferential direction thereof and having a circumferentially arcuate surface, wherein a constant force is always applied to the movable-side roll body portion toward the fixed-side roll body portion. While the pressing means is provided, the elastic means for pushing back the movable roll body portion in the direction away from the fixed roll body portion is disposed, and the pushing force of the elastic means is reduced by the pressing means. 10μm for the increase of the roll gap from the balance position with the urging force
A heat sealing apparatus characterized in that the pressure is reduced within the range of 2 to 8 kgf per unit.