Method for manufacturing gusseted bottom packaging bag, manufacturing apparatus for gusseted bottom packaging bag, method for manufacturing package, and manufacturing apparatus for package

Abstract

A method for manufacturing a rectangular-bottomed packaging bag has: an expansion step in which a pair of opening / closing plates (13) inserted into a flat bag are caused to separate from each other along the thickness direction of the flat bag, thereby expanding the flat bag; and a gusset formation step in which, after the expansion step, folding plates (11, 12) are thrust between the pair of opening / closing plates (13) from the exterior of the bag toward the interior of the bag, thereby forming a side-part gusset and a bottom gusset.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a square-bottom packaging bag, an apparatus for manufacturing a square-bottom packaging bag, a method for manufacturing a package, and an apparatus for manufacturing a package. This application claims priority based on Japanese Patent Application No. 2020-056464 filed in Japan on March 26, 2020, the content of which is incorporated herein by reference.

Background Art

[0002] Conventionally, a square-bottom type packaging bag having three gussets, namely, a bottom gusset and two side gussets (hereinafter referred to as "square-bottom packaging bag") is known. Since the square-bottom packaging bag has excellent characteristics in terms of storage capacity, self-standing property, appearance quality, etc., it is widely used, for example, for packaging pharmaceuticals and foods.

[0003] Various aspects have been disclosed as methods for manufacturing such square-bottom packaging bags. For example, Patent Document 1 discloses a method for manufacturing a square-bottom packaging bag from a flat bag having a bottom gusset. The flat bag is formed of a film having heat-sealability on the inner and outer surfaces such that four pieces, namely, the front surface portion of the bag, the rear surface portion of the bag, and both end edges of the bottom gusset, are integrated by a heat sealer. According to the technique described in Patent Document 1, after sucking and separating a predetermined range of the front surface portion and the rear surface portion of the formed flat bag, folding plates facing the center of both side surfaces and a folding plate facing the center of the lower surface are respectively pushed into the bag from the outside of the bag to the inside of the bag, whereby it is said that a bottom gusset and side gussets can be formed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique described in Patent Document 1, when bringing the front and rear bag portions into close contact while pushing in the folding plate, the specific holding mode of how to hold the bag was unclear. For this reason, it was unclear whether the intended square-bottom packaging bag could be manufactured. Also, in the step of forming a flat bag, when the peripheral edge of the bottom gusset was sealed by a general bag-making machine described in Patent Document 1 using a film having heat-sealability on both the inner and outer surfaces, the four films at the front and rear bag portions and both end edges of the bottom gusset were integrated, and the bottom gusset could not be opened. For this reason, there was a possibility that productivity would decrease. Also, when the manufactured square-bottom packaging bag is filled with contents, it may be shipped as a package filled with the contents. In such a case, it has been desired to improve the productivity in a series of operations from the manufacture of the square-bottom packaging bag to the filling of the contents.

[0006] Therefore, the present invention clarifies a method for holding a flat bag when manufacturing a square-bottom packaging bag having three-sided gussets from a flat bag having a bottom gusset, and provides a method for manufacturing a square-bottom packaging bag with improved productivity, a manufacturing apparatus for the square-bottom packaging bag, a method for manufacturing a package, and a manufacturing apparatus for the package.

Means for Solving the Problems

[0007] A first aspect of the present invention is a method for manufacturing a square-bottom packaging bag having three-sided gussets from a flat bag, the method including an expanding step of expanding the flat bag from the inside of the bag so that the opening cross-section of the flat bag has a square shape, and after the expanding step, a gusset forming step of forming side gussets and forming a bottom gusset while holding the formed side gussets. It is a method for manufacturing a square-bottom packaging bag having the above.

[0008] The second aspect of the present invention is that the expanding step includes a plate inserting step of inserting a pair of opening / closing plates into the flat bag, and a plate separating step of separating the pair of opening / closing plates inserted into the flat bag along the thickness direction of the flat bag. In the gusset forming step, a folding plate is pushed between the pair of opening / closing plates from the outside of the bag toward the inside of the bag to form the side gussets and the bottom gusset, which is a manufacturing method of a square-bottom packaging bag.

[0009] The third aspect of the present invention is a manufacturing method of a square-bottom packaging bag having a column joining portion forming step of forming a column joining portion extending along the four corners of the opening cross-section by joining the peripheral portions of the side gussets after the gusset forming step.

[0010] The fourth aspect of the present invention has a flat bag manufacturing step of manufacturing the flat bag before the expanding step. In the flat bag manufacturing step, a side joining portion formed on the side of the flat bag, a bottom joining portion formed on the bottom of the flat bag, and an inclined joining portion formed at a corner where the side joining portion and the bottom joining portion intersect and connecting the side joining portion and the bottom joining portion are formed, which is a manufacturing method of a square-bottom packaging bag.

[0011] The fifth aspect of the present invention is a manufacturing method of a square-bottom packaging bag in which the expanding step is continuously performed after the flat bag manufacturing step.

[0012] The sixth aspect of the present invention is a manufacturing apparatus for a square-bottom packaging bag for manufacturing the square-bottom packaging bag by the above-described manufacturing method of the square-bottom packaging bag, including a pair of opening / closing plates that can be opened and closed to expand the flat bag from the inside of the bag so that the cross-section of the flat bag becomes a square shape, a side folding plate that enters between the pair of opening / closing plates to form the side gussets, and a bottom folding plate that enters between the pair of opening / closing plates to form the bottom gussets.

[0013] The seventh aspect of the present invention is a method for manufacturing a package, which includes, after the step of implementing the method for manufacturing the above-described gusseted bottom packaging bag, successively, a filling step of filling the manufactured gusseted bottom packaging bag with contents to manufacture a package.

[0014] The eighth aspect of the present invention is a manufacturing apparatus for a package for manufacturing the package by the above-described method for manufacturing a package, which is a manufacturing apparatus for a package having a filling device for filling the gusseted bottom packaging bag with contents.

Advantages of the Invention

[0015] According to the present invention, it is possible to clarify a method for holding a flat bag when manufacturing a gusseted bottom packaging bag having three-sided gussets from a flat bag having a bottom gusset, and to provide a method for manufacturing a gusseted bottom packaging bag with improved productivity, a manufacturing apparatus for a gusseted bottom packaging bag, a method for manufacturing a package, and a manufacturing apparatus for a package.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Mode for Carrying Out the Invention

[0017] Embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals, and redundant descriptions of these components may be omitted.

[0018] (Method for manufacturing a package) FIG. 1 is a perspective view of a package 10 according to an embodiment. FIG. 2 is a front view of a flat bag 9 according to an embodiment. FIG. 3 is an external perspective view of a square-bottom packaging bag 1 according to an embodiment. FIG. 4 is a bottom view of the square-bottom packaging bag 1 according to an embodiment. FIG. 5 is a partial perspective view showing the inside of the square-bottom packaging bag 1 according to an embodiment. The method for manufacturing a package of the present invention for manufacturing the package 10 shown in FIG. 1 is a method of manufacturing by forming a square-bottom packaging bag 1 from a flat bag 9 (see FIG. 2) and filling the inside of the square-bottom packaging bag 1 with a content C1, thereby manufacturing a package 10 corresponding to a square-bottom package in a state where the content C1 is filled. The method for manufacturing a package includes a step of implementing the method for manufacturing a square-bottom packaging bag of the present invention and a filling step.

[0019] (Method for manufacturing a square-bottom packaging bag) The method for manufacturing the gusseted bottom packaging bag 1 shown in Fig. 3 constitutes a process of implementing the method for manufacturing the gusseted bottom packaging bag before the content C1 is filled in the method for manufacturing the package. The method for manufacturing the gusseted bottom packaging bag is a method of manufacturing by bending a flat bag 9 (see Fig. 2) having one bottom gusset 21 in a specific manner to form a gusseted bottom packaging bag 1 having one bottom gusset 21 (see Fig. 4) and two side gussets 35 with different lengths from the bottom gusset 21 (see Fig. 2) of the flat bag 9.

[0020] More specifically, the method for manufacturing the gusseted bottom packaging bag of the present invention includes a case of manufacturing the gusseted bottom packaging bag 1 from a pre-manufactured flat bag 9, and a case of manufacturing the gusseted bottom packaging bag 1 continuously or discontinuously after the flat bag manufacturing process for manufacturing the flat bag 9. An example of the flat bag manufacturing process for manufacturing the flat bag 9 is shown below. As shown in Fig. 11, in the flat bag manufacturing process, the strip-shaped film 16 fed out from the raw material roll is bent multiple times to manufacture a flat bag 9 that can become the gusseted bottom packaging bag 1. The film 16 is a biaxially stretched film or a uniaxially stretched film formed of a material such as polyethylene terephthalate, polypropylene, or polyamide, and a resin layer made of a polyethylene-based resin or a polypropylene-based resin such as low-density polyethylene or linear low-density polyethylene formed by a sealant film or extrusion lamination is laminated. In addition, as a film 16 that exhibits a gas barrier function for blocking oxygen and water vapor, a vapor deposition film on which a metal such as aluminum or a metal oxide such as aluminum oxide or silicon oxide is vapor-deposited may be laminated.

[0021] In the flat bag manufacturing process, first, a bottom gusset 21 is formed by bending a cross-section orthogonal to the longitudinal direction of one film 16 into a W shape. The bottom gusset 21 is formed between a pair of flat portions 15 formed by bending the film 16. The bottom gusset 21 is a double fold that protrudes inward of the bag.

[0022] Next, by joining the two end edges of the pair of flat portions 15, a side joint portion 33 is formed. Next, by joining the pair of flat portions 15 and the peripheral edge portion of the bottom gusset 21, a bottom joint portion 22 is formed. Both end portions of the bottom joint portion 22 are connected to the side joint portion 33. The bottom joint portion 22 is provided at the boundary portion between one of the pair of flat portions 15 and the bottom gusset 21 and the boundary portion between the other of the pair of flat portions 15 and the bottom gusset 21, respectively.

[0023] Next, at the corner where the side joint portion 33 and the bottom joint portion 22 intersect, an inclined joint portion 34 is formed by obliquely connecting between the side joint portion 33 and the bottom joint portion 22. That is, at the corner of the flat bag 9 including the portion where the side joint portion 33 and the bottom joint portion 22 are connected, an inclined joint portion 34 for connecting the side joint portion 33 and the bottom joint portion 22 is provided, and the inclined joint portion 34 is inclined so as to approach the bottom joint portion 22 as it moves away from the side joint portion 33. At this time, the inclination angle of the inclined joint portion 34 with respect to the side joint portion 33 and the bottom joint portion 22 is about 45°. The end portion of the inclined joint portion 34 on the side joint portion 33 side is provided at a position equivalent to the folding line of the bottom gusset 21 in the height direction of the flat bag 9 (the longitudinal direction of the side joint portion 33). Note that the order of forming the side joint portion 33, the bottom joint portion 22, and the inclined joint portion 34 is not limited to the above, and a plurality of these joint portions may be formed simultaneously.

[0024] Here, in the flat bag manufacturing process, the above-described side joint portion 33, bottom joint portion 22, and inclined joint portion 34 are formed by heating the heat-sealing layer provided on one side of the film 16. The heat-sealing layer is formed on the inner side surface of the bag of the film 16. The sealant film constituting the heat-sealing layer is formed of a polyethylene-based unstretched film such as polypropylene, low-density polyethylene, linear low-density polyethylene, or resin. In the flat bag manufacturing process, the heat-sealing layers are fused by applying heat and pressure at positions corresponding to the respective joint portions 22, 33, 34. Thereby, the bottom joint portion 22, the side joint portion 33, and the inclined joint portion 34 are formed.

[0025] Furthermore, the lower end portion 33b of the side joint portion 33, which is located on the bottom gusset 21 side, has the outer surfaces of the film 16 joined together, so that one surface and the other surface (the surfaces facing each other) of the double-folded bottom gusset 21 are joined to each other. In the portion where the outer surfaces of a part of the film 16 are joined together like this, a heat seal coat is applied to the outer surface of the film 16. The heat seal coat can be formed, for example, in the printing process of the film 16. Also, a hot melt adhesive may be used. By these means, it is possible to join the outer surfaces of the film 16 that do not have a heat-sealing layer. Depending on the use of the square-bottom packaging bag 1, it may not be necessary to join the outer surfaces of the film 16, but it is preferable to join the outer surfaces of the film 16 because the self-standing property of the square-bottom packaging bag 1 is enhanced.

[0026] In this way, in the flat bag manufacturing process, after folding a single film 16, by joining predetermined locations, a flat bag 9 having an opening 8 on one side and one bottom gusset 21 at the end opposite to the opening 8 is formed.

[0027] In the square-bottom packaging bag manufacturing process for implementing the manufacturing method of the square-bottom packaging bag of the present invention, the square-bottom packaging bag 1 shown in FIGS. 3 to 5 is manufactured from the flat bag 9. Here, first, the configuration of the square-bottom packaging bag 1 will be described. The square-bottom packaging bag 1 has a rectangular (square) bottom surface 2, a front surface 3, a rear surface 4, and a pair of side surfaces 5. In the following description regarding the square-bottom packaging bag 1, the direction in which the front surface 3 and the rear surface 4 face each other may be referred to as the front-rear direction. Also, the direction in which the pair of side surfaces 5 face each other may be referred to as the left-right direction. Also, the direction orthogonal to both the front-rear direction and the left-right direction may be referred to as the up-down direction or the height direction. Also, in the up-down direction, the side where the bottom surface 2 is located may be referred to as the lower side, and the opposite side may be referred to as the upper side. The front surface 3 and the rear surface 4 rise upward from the two long sides of the bottom surface 2 respectively, and are disposed opposite to each other with the bottom surface 2 therebetween. The front surface 3 and the rear surface 4 are formed in a rectangular shape. The pair of side surfaces 5 rise upward from the two short sides of the bottom surface 2 and connect the front surface 3 and the rear surface 4. One of the pair of side surfaces 5 is the right side surface 6. The other of the pair of side surfaces 5 is the left side surface 7. An opening 8 that communicates the inside and outside of the gusseted bottom bag 1 is provided at the end (upper end) on the side opposite to the bottom surface 2 among the front surface 3, the rear surface 4, and the pair of side surfaces 5. A first boundary line L1 extending in the height direction of the gusseted bottom bag 1 is provided between the front surface 3 and the left side surface 7. In other words, the front surface 3 and the left side surface 7 are continuously formed via the first boundary line L1. Similarly, the front surface 3 and the right side surface 6 are continuously formed via a second boundary line L2 extending in the height direction. The rear surface 4 and the left side surface 7 are continuously formed via a third boundary line L3 extending in the height direction. The rear surface 4 and the right side surface 6 are continuously formed via a fourth boundary line L4 extending in the height direction.

[0028] As shown in FIG. 4, the bottom surface 2 of the gusseted bottom bag 1 has a bottom gusset 21. In the gusseted bottom bag 1, the bottom gusset 21 has a valley fold portion 25 that is folded so as to protrude inward of the bag and a mountain fold portion 26 that is folded so as to protrude outward of the bag. The valley fold portion 25 is provided at an intermediate portion between the front surface 3 and the rear surface 4. The valley fold portion 25 has a straight line portion 25a that is parallel to the front surface 3 and the rear surface 4 and terminates inside the peripheral edge of the bottom surface 2, and a V-shaped portion 25b that extends from both end portions 25c of the straight line portion 25a toward the respective corner portions of the corresponding (proximate) bottom surface 2. The mountain fold portion 26 extends substantially perpendicularly from both end portions 25c of the straight line portion 25a in the valley fold portion 25 toward the short side of the bottom surface 2. By folding the bottom gusset 21 along the valley fold portion 25 and the mountain fold portion 26 so as to protrude inward of the bag, the bottom surface 2 is folded in half so that the front surface 3 and the rear surface 4 approach each other.

[0029] As shown in FIGS. 3 and 4, the bottom joint portion 22 is formed at the periphery of the bottom surface 2. The bottom joint portion 22 extends from the lower ends of the front surface 3, the rear surface 4, the left side surface 7, and the right side surface 6 with a certain width and extends on the same plane as these surfaces, and is provided on the entire circumference of the square-bottomed packaging bag 1. The bottom joint portion 22 protrudes below the bottom surface 2. As a result, the square-bottomed packaging bag 1 stands on its own with the bottom joint portion 22 serving as legs.

[0030] As shown in FIG. 3, an inclined joint portion 34 is formed on the side surface 5. The inclined joint portion 34 is formed on the front surface 3 side and the rear surface 4 side of the side surface 5 with respect to the side joint portion 33, respectively. The inclined joint portion 34 is inclined so as to gradually approach the bottom surface 2 side as it goes from the side joint portion 33 toward the front surface 3 or the rear surface 4. The bottom surface side end portion 44 located on the bottom surface 2 side of the inclined joint portion 34 is connected to the bottom joint portion 22. The side joint portion 33, the bottom joint portion 22, and the inclined joint portion 34 are formed in a right-angled isosceles triangle shape with the inclined joint portion 34 as the hypotenuse. That is, the inclined joint portion 34 is formed so as to form a right-angled isosceles triangle shape together with a part of the side joint portion 33 and a part of the bottom joint portion 22 with the inclined joint portion 34 as the hypotenuse. The bottom surface side end portion 44 where the outer (upper) side of the inclined joint portion 34 formed with a certain width intersects the bottom joint portion 22 serves as the base points of the four sides of the square-bottomed packaging bag 1.

[0031] As shown in FIG. 5, an isosceles triangular folding portion 42 is formed inside the side surface 5 of the square-bottomed packaging bag 1 (only the left side surface 7 side is shown in FIG. 5). The folding portion 42 is continuous with the bottom surface 2 via the bottom joint portion 22. The folding portion 42 has a right-angled isosceles triangle shape with the side overlapping the short side of the bottom surface 2 as the hypotenuse 42a when viewed from the inside of the square-bottomed packaging bag 1. The two equal sides 42b of the folding portion 42 are provided on the side surface 5. The two equal sides 42b of the folding portion 42 are inclined toward the bottom surface 2 side as they go from an arbitrary point on the side joint portion 33 (any point on the side joint portion 33 that is connected to the side surface 5) toward the front surface 3 or the rear surface 4 with the arbitrary point as the vertex. The two equal sides 42b of the folding portion 42 coincide with the outer side of the inclined joint portion 34. That is, the inclined joint portion 34 positions the folding portion 42.

[0032] On the back side of the folding portion 42 (the outside of the bag), a sandwiched portion 45 (see FIG. 3) continuous with the folding portion 42 is provided along a perpendicular line drawn from the vertex having an approximately 90-degree angle of the triangular shape to the opposite side that overlaps the short side of the bottom surface 2. The sandwiched portion 45 is sandwiched by the side joint portion 33. Since the sandwiched portion 45 is sandwiched by the side joint portion 33, the top of the folding portion 42 is connected to the side surface 5. The sandwiched portion 45 is provided below the side joint portion 33. The sandwiched portion 45 is provided between the lowermost end portion 33b of the side joint portion 33 and the position corresponding to the top of the inclined joint portion 34 (the position at the same height).

[0033] When viewed from the inside of the bag, the two equal sides 42b of the folding portion 42 and the side surface 5 are joined by the inclined joint portion 34. As a result, the gap between the equal side 42b of the folding portion 42 and the side surface 5 is blocked, so that when the corner-bottom packaging bag 1 is filled with the content C1, the content C1 is prevented from entering the gap between the folding portion 42 and the side surface 5.

[0034] As shown in FIG. 3, the side gussets 35 are provided on the left side surface 7 and the right side surface 6, respectively, and have joint portions derived from the side joint portion 33 of the flat bag 9. The side gussets 35 are bent on the right side surface 6 and the left side surface 7 so as to protrude inward of the bag when the corner-bottom packaging bag 1 is closed at the center in the width dimension along the front-back direction (the thickness direction of the front surface 3 and the back surface 4) between the front surface 3 and the back surface 4.

[0035] Next, a method for manufacturing a corner-bottom packaging bag for manufacturing the corner-bottom packaging bag 1 of the present invention will be described. In the present embodiment, the above-described corner-bottom packaging bag 1 is manufactured from a flat bag. Specifically, the method for manufacturing a corner-bottom packaging bag includes an expanding step and a gusset forming step, and preferably includes a pressing step and a column joint portion forming step.

[0036] In the expanding process, the flat bag 9 is expanded from the inside of the bag so that the opening cross-section of the flat bag 9 (the cross-sectional shape of the flat bag 9 in the direction orthogonal to the opening direction) becomes a rectangular shape. The expanding process includes a plate insertion process and a plate separation process. FIG. 6 is an explanatory diagram showing the plate insertion process according to the embodiment. FIG. 7 is an explanatory diagram showing the plate separation process according to the embodiment.

[0037] As shown in FIG. 6, in the plate insertion process, a pair of opening / closing plates 13 that can be opened and closed are inserted into the flat bag 9 from the opening 8 of the flat bag 9 in a state where they are close to each other. Alternatively, the flat bag 9 is moved so as to cover the pair of opening / closing plates 13, thereby inserting the pair of opening / closing plates 13 into the flat bag 9 from the opening 8. The pair of opening / closing plates 13 are arranged to face each other in the thickness direction of the flat bag 9 (the direction in which the pair of flat portions 15 face each other). The pair of opening / closing plates 13 are formed in the same rectangular shape. The width dimension W1 of the opening / closing plate 13 along the left-right direction is equal to the dimension W2 between the bottom surface side end portions 44 (see FIG. 2) of the inclined joint portions 34 formed in pairs at both end portions of the bottom joint portion 22.

[0038] As shown in FIG. 7, in the plate separation step, a pair of opening / closing plates 13 inserted inside the flat bag 9 are separated from each other along the thickness direction of the flat bag 9. As a result, the front surface 3, the rear surface 4, and a pair of side surfaces 5 are formed, and the bottom surface 2 is formed by opening the double-folded bottom gusset 21. Specifically, in the plate separation step, the film 16 is bent at a position corresponding to (contacting) the left end portion of one of the opening / closing plates 13 in the flat portion 15 of the flat bag 9, thereby forming the first boundary line L1. The film 16 is bent at a position corresponding to (contacting) the right end portion of one of the opening / closing plates 13 in the flat portion 15, thereby forming the second boundary line L2. The film 16 is bent at a position corresponding to (contacting) the left end portion of the other opening / closing plate 13 in the flat portion 15, thereby forming the third boundary line L3. The film 16 is bent at a position corresponding to (contacting) the right end portion of the other opening / closing plate 13 in the flat portion 15, thereby forming the fourth boundary line L4. The surface between the first boundary line L1 and the second boundary line L2 is the front surface 3. The surface between the third boundary line L3 and the fourth boundary line L4 is the rear surface 4. The surface between the first boundary line L1 and the third boundary line L3 is the left side surface 7. The surface between the second boundary line L2 and the fourth boundary line L4 is the right side surface 6. The portion provided on the side opposite to the opening 8 with the first boundary line L1, the second boundary line L2, the third boundary line L3, and the fourth boundary line L4 at the four corners is the bottom surface 2.

[0039] FIG. 8 is an explanatory view showing a folding start state in the gusset forming step according to the embodiment. FIG. 9 is an explanatory view showing a folding end state in the gusset forming step according to the embodiment. As shown in FIGS. 8 and 9, in the gusset forming step, after the expanding step, a pair of side gussets 35 are formed, and the bottom gusset 21 is formed while holding the formed side gussets 35. In the gusset forming step, while pushing a pair of side folding plates 11 facing the left side surface 7 and the right side surface 6 and a bottom folding plate 12 facing the bottom surface 2 (see FIG. 14) from the outside of the bag toward the inside of the bag, a pair of flat portions 15 (the front surface 3 and the rear surface 4) are brought into close contact with each other. As a result, the side gussets 35 and the bottom gusset 21 are formed respectively.

[0040] Specifically, as shown in FIG. 8, in the gusset forming step, first, along the central portions in the width direction of the left side surface 7 and the right side surface 6, the side folding plate 11 parallel to the opening / closing plate 13 is inserted (pushed in) toward the inside of the bag. Further, along the central portion in the width direction (short side direction, front-rear direction) of the bottom surface 2, the bottom folding plate 12 (see FIG. 14) parallel to the opening / closing plate 13 is inserted (pushed in) toward the inside of the bag. At this time, the width dimension W3 (see FIG. 14) of the bottom folding plate 12 along the left-right direction is smaller than the width dimension W4 of the bottom surface 2 along the left-right direction. The side folding plate 11 and the bottom folding plate 12 are inserted between the pair of opening / closing plates 13.

[0041] As shown in FIG. 9, when the insertion of the side folding plate 11 and the bottom folding plate 12 is started, the pair of opening / closing plates 13 are brought closer again according to the insertion depth of the side folding plate 11 and the bottom folding plate 12. After the side folding plate 11 and the bottom folding plate 12 are inserted to a predetermined depth, the side folding plate 11 and the bottom folding plate 12 are pulled out toward the outside of the bag with the opening / closing plates 13 closed. Thereby, a three-sided gusset bag (the corner-bottom packaging bag 1 in a closed state) in which the bottom gusset 21 and the side gusset 35 protruding toward the inside of the bag are formed is formed.

[0042] In the pressing step, by pressing the folded portion of the film 16 formed in the gusset forming step, creases are formed so that the folds are maintained. Specifically, in the pressing step, both side ends of the corner-bottom packaging bag 1 in which the four boundary lines L1, L2, L3, and L4 are formed are heated and pressed. Thereby, since the four boundary lines L1, L2, L3, and L4 remain even when the corner-bottom packaging bag 1 is in an open state (see FIGS. 3 and 17), it becomes easier to maintain the opening cross-sectional shape in a square shape. Therefore, when the corner-bottom packaging bag 1 is filled with the content C1, the silhouette of the corner-bottom packaging bag 1 does not become rounded, the appearance quality of the corner-bottom packaging bag 1 can be improved, and the self-standing property of the corner-bottom packaging bag 1 can be improved.

[0043] In the column joint forming step, four column joints 31 extending along the four corners of the opening cross-section are formed by joining the peripheral edges of the side gussets 35. In the column joint forming step, the column joints 31 are respectively formed along the first boundary line L1, the second boundary line L2, the third boundary line L3, and the fourth boundary line L4. Specifically, in the column joint forming step, in the corner-bottom packaging bag 1 in a state where the front surface 3 and the rear surface 4 are in close contact (closed state, see Fig. 9), the edge portions where the inner surfaces of the front surface 3 and the left side surface 7 face each other are heated and pressed. By joining the edges of the front surface 3 and the left side surface 7 to each other in this way, the column joint 31 along the first boundary line L1 is formed. The column joints 31 are respectively formed at corresponding positions for the second boundary line L2, the third boundary line L3, and the fourth boundary line L4 by the same procedure. The formed column joints 31 project such that the film 16 bulges outward of the bag along the respective boundary lines L1, L2, L3, and L4. The lower end portion 31a located on the bottom surface 2 side of the column joint 31 is connected to the bottom joint 22. However, the inner surface side of the portion where the bottom joint 22 of the lower end portion 31a overlaps is not joined in the film in which the heat-sealing layer is formed only on one side of the film 16. The inner edge of the column joint 31 approximately forms the corner of the corner-bottom packaging bag 1.

[0044] In the filling step, after the step of implementing the manufacturing method of the corner-bottom packaging bag, the manufactured corner-bottom packaging bag 1 is continuously filled with the content C1 to manufacture the package 10. In the filling step, first, the manufactured corner-bottom packaging bag 1 is opened again. Next, the content C1 is filled into the corner-bottom packaging bag 1 from the opening 8. Finally, the opening 8 is closed by sealing the film 16 near the opening 8. Thereby, the package 10 in a state where the corner-bottom packaging bag 1 is filled with the content C1 is manufactured. Note that in the filling step, before filling the content C1, for example, a chuck or the like that can open and close the opening 8 of the corner-bottom packaging bag 1 may be formed at the opening 8. In this case, after filling the content C1, the opening 8 can be closed by closing the chuck in conjunction with sealing the film 16. Also, these chucks or the like may be provided at the stage of the manufacturing process of the flat bag 9, for example, in a process before the filling step.

[0045] (Manufacturing Apparatus for the Package) Next, a manufacturing apparatus 50 for the above-described package 10 will be described. FIG. 10 is a plan view of a manufacturing apparatus 50 for a package according to an embodiment. The manufacturing apparatus 50 for the package is an apparatus for manufacturing the package 10 by the above-described manufacturing method for the package. The manufacturing apparatus 50 for the package includes a flat bag manufacturing apparatus 51, a square-bottomed packaging bag manufacturing apparatus 52 (manufacturing apparatus for the square-bottomed packaging bag described in the claims), and a filling apparatus 53. The square-bottomed packaging bag manufacturing apparatus 52 is provided on the downstream side of the manufacturing process from the flat bag manufacturing apparatus 51. The filling apparatus 53 is provided on the downstream side of the manufacturing process from the square-bottomed packaging bag manufacturing apparatus 52.

[0046] FIG. 11 is an external view of a flat bag manufacturing apparatus 51 according to an embodiment. The flat bag manufacturing apparatus 51 is an apparatus for manufacturing the flat bag 9 from a single film 16 by the above-described flat bag manufacturing process. The flat bag manufacturing apparatus 51 includes a raw material roll 54 around which a film 16 that is a material for the square-bottomed packaging bag 1 is wound, a plurality of rollers 55, two contact plates 56, an adhesion part 57, and a cutting part 58.

[0047] The raw material roll 54 has a strip-shaped film 16 wound around it. The plurality of rollers 55 send the film 16 while supporting the film 16 fed from the raw material roll 54. Among the plurality of rollers 55, a pair of first clamping rollers 55a and a pair of second clamping rollers 55b are arranged on the downstream side. Each of the clamping rollers 55a and 55b clamps the strip-shaped film 16 in a state where a pair of flat portions 15 (see FIG. 2) are formed by folding the film 16 in half along the longitudinal direction.

[0048] The two contact plates 56 have a function of bending the strip-shaped film 16. Among the two contact plates 56, the upstream contact plate 56a is upstream of the first clamping roller 55a, and folds the film 16 in half so as to bisect the film 16 in its width direction, resulting in a film 16 having a V-shaped cross section. Of the two abutting plates 56, the downstream abutting plate 56b is provided between the first clamping roller 55a and the second clamping roller 55b. The abutting plate 56b abuts on the mountain-fold portion (the portion including the fold line of the mountain fold) of the double-folded film 16 sent by the first clamping roller 55a. The abutting plate 56b bends the film 16 so that the mountain-fold portion of the film 16 becomes a valley fold that is convex on the opposite side. Thereby, the abutting plate 56b forms the film 16 having a W-shaped cross section with a bottom gusset 21 from the film 16 having a V-shaped cross section. That is, the second clamping roller 55b provided on the downstream side of the abutting plate 56 clamps the film 16 having a W-shaped cross section.

[0049] The bonding portion 57 is provided on the downstream side of the second clamping roller 55b. The bonding portion 57 has a bottom bonding portion 57a and a side bonding portion 57c. The bottom bonding portion 57a is provided along the lower side of the film 16 having a W-shaped cross section. The bottom bonding portion 57a sandwiches the lower end portion of the film 16 from both sides with a pair of seal dies M having convex portions corresponding to the bottom joint portion 22 and the inclined joint portion 34, and heats and presses them to bond the inner surfaces of the film 16 together. The bottom bonding portion 57a simultaneously forms the bottom joint portion 22 and the inclined joint portion 34 in the flat bag 9 described above. A bottom cooling portion 57b is arranged on the downstream side of the bottom bonding portion 57a. The bottom cooling portion 57b cools the film 16 heated by the bottom bonding portion 57a.

[0050] The side bonding portion 57c is provided along the height direction (the direction perpendicular to the bottom bonding portion 57a) of the film 16 having a W-shaped cross section. The side bonding portion 57c sandwiches the portion that can become the side portion of the flat bag 9 from both sides (both sides in the thickness direction), heats and presses them to bond the films 16 together. The side bonding portion 57c forms the side joint portion 33 (see FIG. 2) in the flat bag 9 described above. A side cooling portion 57d is arranged on the downstream side of the side bonding portion 57c. The side cooling portion 57d cools the film 16 heated by the side bonding portion 57c.

[0051] The cutting part 58 is provided on the downstream side of the bonding part 57. The cutting part 58 cuts the film 16 at regular intervals. Before being cut by the cutting part 58, the film 16 is in a state where the above-mentioned flat bags 9 are continuous in the width direction, that is, a state where the side joining parts 33 of the flat bags 9 are connected to each other. The cutting part 58 cuts between the side joining parts 33 of the continuous flat bags 9 for each width of the flat bags 9 along the short side direction of the film 16. Thereby, the flat bag 9 is formed. The flat bag 9 manufactured by the flat bag manufacturing apparatus 51 is supplied to the bag feeding apparatus 60 (see FIG. 10) of the square bottom packaging bag manufacturing apparatus 52.

[0052] As shown in FIG. 10, the square bottom packaging bag manufacturing apparatus 52 is an apparatus for manufacturing the square bottom packaging bag 1 in a state before being filled with the content C1 from the flat bag 9 manufactured by the flat bag manufacturing apparatus 51 by the above-mentioned method for manufacturing a square bottom packaging bag. The square bottom packaging bag manufacturing apparatus 52 includes a bag feeding apparatus 60, an opening and closing apparatus 70, a folding apparatus 80, a pressing apparatus 90, and a recovery apparatus 100. The bag feeding apparatus 60 is an apparatus for supplying the flat bag 9 manufactured by the flat bag manufacturing apparatus 51 to the opening and closing apparatus 70. The bag feeding apparatus 60 includes a conveying part 61 such as a belt conveyor and a bag feeding arm 62. The conveying part 61 conveys the flat bags 9 one by one at intermittent feeding toward the opening and closing apparatus 70. The bag feeding arm 62 is provided at a position (proximate position) corresponding to the bag receiving part 63 where the bag feeding arm 62 receives the bag in the bag feeding apparatus 60. The bag feeding arm 62 adsorbs the flat bag 9 from both sides by, for example, a vacuum suction pad to open the flat bag 9, and moves the flat bag 9 from the bag receiving part 63 in a state where the opening 8 is open, thereby feeding the bag to the opening and closing apparatus 70. Note that the bag feeding apparatus 60 may include, for example, a bag magazine (not shown) that stores a plurality of stacked flat bags 9. In this case, the flat bag 9 may be supplied from the bag magazine to the opening and closing apparatus 70 via the conveying part 61.

[0053] The opening and closing apparatus 70 is disposed at a position (proximate position) corresponding to the bag receiving part 63 of the bag feeding apparatus 60. The opening and closing apparatus 70 includes a rotary table 71 and a plurality of pairs of opening and closing plates 13. The rotary table 71 is formed in a circular shape centered on a rotation axis O1 along the vertical up-and-down direction (hereinafter simply referred to as the up-and-down direction). The rotary table 71 rotates about the rotation axis O1 with respect to the floor surface F. The rotary table 71 has eight stations from A to H at every 45° of rotation angle, with the position corresponding to the bag receiving portion 63 of the bag feeding device 60 as station A. By rotating 45° each time, the opening and closing plates 13 are intermittently fed to each station of the rotary table 71 in order.

[0054] The pair of opening and closing plates 13 are provided at the outer peripheral portion of the rotary table 71. The pair of opening and closing plates 13 are respectively provided at positions corresponding to each station of the rotary table 71. In other words, in the present embodiment, eight pairs of opening and closing plates 13 are provided at equal intervals along the circumferential direction of the rotary table 71. The pair of opening and closing plates 13 expand the flat bag 9 from the inside of the bag so that the opening cross-section of the flat bag 9 is square-shaped.

[0055] FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 10. In FIG. 12, the illustration of the flat bag 9 (the gusseted bottom packaging bag 1) is omitted for the sake of explanation. The pair of opening and closing plates 13 is attached to the rotary table 71 via a base member 72 attached to the rotary table 71. Specifically, the pair of opening and closing plates 13 is attached to an actuator 73 that is movable along the vertical direction provided on the base member 72. The pair of opening and closing plates 13 is arranged to face each other in the vertical direction. The pair of opening and closing plates 13 protrudes from the base member 72 toward the outer diameter side of the rotary table 71. When the actuator 73 is driven, the pair of opening and closing plates 13 can be opened and closed between a closed state (see FIG. 6) where the opening and closing plates 13 are close to each other and an open state (see FIG. 7) where the opening and closing plates 13 are separated. The separation dimension of the pair of opening and closing plates 13 in the open state is equal to the separation dimension between the front surface 3 and the rear surface 4 of the square-bottomed packaging bag 1. The opening and closing plates 13 are formed in a square shape in plan view. The width dimension W1 (see FIG. 10) of the opening and closing plates 13 along the circumferential direction of the rotary table 71 is equal to the width dimension W4 (see FIG. 8) of the square-bottomed packaging bag 1. The length dimension T1 of the opening and closing plates 13 along the radial direction of the rotary table 71 is larger than the height dimension T2 (see FIG. 3) from the opening 8 to the bottom of the square-bottomed packaging bag 1. The square-bottomed packaging bag 1 is held by the pair of opening and closing plates 13 when the pair of opening and closing plates 13 contacts it from the inside of the bag.

[0056] FIG. 13 is a plan view of the folding device 80 according to the embodiment. FIG. 14 is a perspective view showing the operation of the folding device 80 according to the embodiment. As shown in FIGS. 10 and 13, the folding device 80 is arranged outside the rotary table 71 in the radial direction. In the present embodiment, the folding device 80 is provided at a position corresponding to (proximate to) the station C of the rotary table 71. The folding device 80 includes a support base 81, a side folding plate 11, and a bottom folding plate 12.

[0057] The support base 81 is installed on the floor surface F. As shown in FIG. 13, the support base 81 has a drive mechanism 82 including a motor (not shown) serving as a drive source and a cam (not shown) and a rack 87 connected to the motor. In the present embodiment, the drive mechanism 82 has a first output shaft 83 along the vertical direction and a second output shaft 84 provided at a position farther from the rotary table 71 than the first output shaft 83 and parallel to the first output shaft 83. A pair of side folding plates 11 are provided on both left and right sides in the lateral direction of the support base 81 along the circumferential direction of the rotary table 71. Since the pair of side folding plates 11 have the same configuration, in the following description, one of the side folding plates 11 will be described and the description of the other side folding plate 11 will be omitted. Each side folding plate 11 has a link mechanism 85 connected to the motor via a cam or the like and a side movable plate 86 connected to the link mechanism 85.

[0058] The link mechanism 85 has a first link arm 85a, a second link arm 85b, and a third link arm 85c. One end of the first link arm 85a is attached to the first output shaft 83. The first link arm 85a swings and rotates about one end when viewed from the vertical direction. Specifically, the first link arm 85a is provided along the left-right direction of the support base 81, and the other end is located outside the one end in the left-right direction (ready state), and the other end is rotated about 90° from the ready state toward the rotary table 71 side. By this, the side folding plate 11 moves between a ready position P1 arranged away from the rotary table 71 and a folding position P2 located on the rotary table 71 side with respect to the ready position P1.

[0059] The second link arm 85b is provided at a position farther from the rotary table 71 than the first link arm 85a. One end of the second link arm 85b is attached to the second output shaft 84. The second output shaft 84 is connected to the first output shaft 83 via a rack 87. The second link arm 85b swings and rotates about one end when viewed from the vertical direction. The first link arm 85a and the second link arm 85b swing and rotate simultaneously while maintaining a substantially parallel state.

[0060] The third link arm 85c is rotatably attached to the other end of the first link arm 85a and the other end of the second link arm 85b, respectively. The third link arm 85c moves toward the rotary table 71 while maintaining a state parallel to the front-rear direction of the support base 81 (the direction along the radial direction of the rotary table 71) as the first link arm 85a and the second link arm 85b swing. That is, when the side folding plate 11 moves from the preparation position P1 to the folding position P2, the pair of left and right third link arms 85c move in the front direction where the rotary table 71 is located and in a direction approaching each other while maintaining a parallel state to each other. Therefore, the movable range of the side folding plate 11 of the folding device 80 can be made compact, and the side movable plate 86 can simultaneously and parallelly contact both side surfaces 5 of the square-bottom packaging bag 1, and the side gusset 35 can be surely formed. Furthermore, the first output shaft 83 and the second output shaft 84 to which the other side folding plate 11 is connected are connected to the first output shaft 83 and the second output shaft 84 to which one side folding plate 11 is connected via spur gears. Therefore, the pair of left and right first output shafts 83 and second output shafts 84 can both rotate at the same rotational speed.

[0061] The side movable plate 86 is fixed to the end of the third link arm 85c extending in the front-rear direction on the side of the rotary table 71. The side movable plate 86 is formed in a plate shape with the vertical direction as the thickness direction. The side movable plate 86 is formed in a rectangular shape with the front-rear direction of the support base 81 as the longitudinal direction. The side movable plate 86 protrudes inward in the left-right direction of the support base 81 from the third link arm 85c. As shown in FIG. 14, in a state where the side folding plate 11 is moving from the preparation position P1 to the folding position P2, the side movable plate 86 is positioned on both sides of the side portion (side surface 5 of the corner-bottom packaging bag 1) of the flat bag 9 held by the opening / closing plate 13 in an open state.

[0062] As shown in FIG. 13, the bottom folding plate 12 is provided between the pair of side folding plates 11. The bottom folding plate 12 is provided at the front end of the support base 81. The bottom folding plate 12 is connected to a linear rack 87 along the front-rear direction. The bottom folding plate 12 moves along the front-rear direction of the support base 81. The bottom folding plate 12 is formed in a plate shape with the vertical direction as the thickness direction. The width dimension W3 along the left-right direction of the bottom folding plate 12 is equal to or less than the width dimension W5 between the side movable plates 86 in the pair of side folding plates 11 located at the folding position P2. The bottom folding plate 12 moves from the preparation position P3 to the folding position P4 toward the opening / closing device 70 side as the side folding plates 11 move from the preparation position P1 to the folding position P2.

[0063] Returning to FIG. 10, the press device 90 is provided on the downstream side of the folding device 80 in the rotation direction of the rotary table 71 in the manufacturing process. In the present embodiment, the press devices 90 are respectively provided at positions corresponding to (proximate to) the stations D, E, and F of the rotary table 71. These press devices 90 have the same configuration except for a part. Therefore, in the following description, the press device 90 installed at the station D will be described, and the differences in the press devices 90 installed at other stations will be described.

[0064] FIG. 15 is a cross-sectional view taken along line XV-XV of FIG. 10. The pressing device 90 provided at station D has a support structure 91 and a pair of temperature plates 92. The temperature plate 92 has a heating function. The support structure 91 is arranged facing the rotating body (rotating table 71) at station D. The support structure 91 is installed on the floor surface F. The support structure 91 has a lower structure 93 located below the opening / closing plate 13 positioned at station D and an upper structure 94 extending to a position above the opening / closing plate 13.

[0065] The pair of temperature plates 92 are respectively attached to the lower structure 93 and the upper structure 94. The temperature plate 92 is formed in a plate shape with the vertical direction as the thickness direction. The opening / closing plate 13 is arranged between the pair of temperature plates 92. The pair of temperature plates 92 are each movable in the vertical direction. The temperature plate 92 sandwiches the opening / closing plate 13 and the square-bottom packaging bag 1 held by the opening / closing plate 13 from both sides in the vertical direction in a state heated to a predetermined temperature. The temperature plate 92 is set to a predetermined temperature, for example, a temperature of 100° C. or lower at which the heat-sealing layer of the film 16 does not melt. By heating and pressing the square-bottom packaging bag 1 (not shown in FIG. 15) in this way, folds such as the gussets 21, 35 and the folded portion 42 of the square-bottom packaging bag 1 are imparted.

[0066] The pressing device 90 provided at station E has a column joint forming plate 95 instead of the pair of temperature plates 92 described above. The column joint forming plate 95 is respectively attached to the lower structure 93 and the upper structure 94. The column joint forming plate 95 sandwiches the side portion of the square-bottom packaging bag 1 from both sides in the vertical direction in a state heated to a predetermined temperature. The column joint forming plate 95 forms a column joint portion 31 (see FIG. 3) in which the inner surfaces of the films 16 are joined by heating and pressing the portion corresponding to the side portion of the square-bottom packaging bag 1. The temperature of the column joint forming plate 95 is higher than the temperature of the temperature plate 92. The press device 90 provided at station F has the above-described temperature plate 92 with a cooling function.

[0067] As shown in FIG. 10, the recovery device 100 is provided on the downstream side in the rotation direction of the rotary table 71 from the press device 90. In the present embodiment, the recovery device 100 is provided at a position corresponding to station G of the rotary table 71. The recovery device 100 includes a recovery arm 101 and a transfer rotary table 102.

[0068] The recovery arm 101 has a vacuum suction pad and removes the square-bottom packaging bag 1 held on the opening / closing plate 13 by adsorbing the square-bottom packaging bag 1. The recovery arm 101 moves the adsorbed square-bottom packaging bag 1 to the transfer rotary table 102. The transfer rotary table 102 rotates around a rotation axis O2 along the vertical direction with respect to the floor surface F. The transfer rotary table 102 conveys the square-bottom packaging bag 1 received from the recovery arm 101.

[0069] The filling device 53 is provided on the downstream side of the manufacturing process from the recovery device 100. The filling device 53 fills the square-bottom packaging bag 1 manufactured by the above-described square-bottom packaging bag manufacturing device 52 with the content C1. Specifically, the filling device 53 opens the opening 8 of the square-bottom packaging bag 1 taken from the transfer rotary table 102 and fills it with the content C1. The filling device 53 has a closing portion (not shown) that seals the opening 8 of the square-bottom packaging bag 1 after filling. Thereby, a package 10 filled with the content C1 in the square-bottom packaging bag 1 is manufactured.

[0070] (Operation of the square-bottom packaging bag manufacturing device) Next, the operations at each station of the above-described square-bottom packaging bag manufacturing device 52 will be described. First, the operation at Station A will be described. Station A is a receiving section where the opening / closing device 70 receives the flat bag 9 from the bag feeding device 60. At Station A, first, the bag feeding arm 62 adsorbs the vicinity of the opening of the flat bag 9 and opens the flat bag 9 in the vertical direction. That is, by the bag feeding arm 62 adsorbing the vicinity of the opening of the flat bag 9 and moving in the vertical direction, the flat bag 9 is opened in a direction orthogonal to the vertical direction. Next, the bag feeding arm 62 moves the flat bag 9 in the opened state toward the pair of opening / closing plates 13. At this time, the pair of opening / closing plates 13 are in the closest proximity state to each other. The bag feeding arm 62 moves the flat bag 9 so as to cover the pair of opening / closing plates 13 in the proximity state from above and below. Next, the vacuum suction pad of the bag feeding arm 62 is detached from the flat bag 9, and the flat bag 9 is supported by the opening / closing plate 13. When the flat bag 9 is supported by the opening / closing plate 13, the rotary table 71 rotates by about 45°, and the opening / closing plate 13 supporting the flat bag 9 moves to Station B.

[0071] At Station B, first, the pair of opening / closing plates 13 are separated to be in a separated state, thereby expanding the flat bag 9 from the inside of the bag. In other words, at Station B, an expanding process is performed. The shape of the bottom surface 2 of the expanded flat bag 9 and the cross-sectional shape as viewed from the opening 8 side are square. Also at this time, the portion that becomes the side surface 5 of the corner-bottom packaging bag 1 bends along the perpendicular line to the bottom surface extending from the vicinity of the bottom surface side end portion 44 (see FIG. 2) of the inclined joint portion 34 toward the opening 8 side, and a folding portion 42 is formed. When the expanding process is completed, the rotary table 71 rotates by about 45°, and the opening / closing plate 13 supporting the expanded flat bag 9 moves to Station C.

[0072] At Station C, a gusset forming process for forming side gussets 35 and bottom gusset 21 is performed. At Station C, first, a motor connected to the link mechanism 85 is driven, and a pair of side folding plates 11 simultaneously move from the preparation position P1 toward the folding position P2. As the pair of side folding plates 11 move simultaneously, the side folding plates 11 are inserted (pushed in) between the pair of opening / closing plates 13 while maintaining parallelism with the opening / closing plates 13. Further, as the insertion depth of the side folding plates 11 increases, the pair of opening / closing plates 13 move from the separated state to the proximity state. Thereby, V-shaped side gussets 35 that protrude inward of the bag are formed on both side surfaces 5 of the flat bag 9.

[0073] More specifically, immediately before the side folding plates 11 start to be inserted and the opening / closing plates 13 reach the fully proximate state, the side folding plates 11 enter (are pushed in) deepest into the bag. When the opening / closing plates 13 reach the proximate state, the side folding plates 11 start to move away from the side gussets 35. After that, when the side folding plates 11 are detached from between the pair of opening / closing plates 13, the side gussets 35 are surely formed by sandwiching the film 16 corresponding to the side surface 5 (the film 16 forming the side surface 5) between the opening / closing plates 13 in the proximate state. When moving to Station C after the expanding process shown in FIG. 14, the shape of the bottom surface 2 of the expanded flat bag 9 and the cross-sectional shape viewed from the opening 8 side are square. However, in the vicinity of the bottom surface 2, as going from the opening 8 toward the bottom surface 2, both side surfaces 5 of the expanded flat bag 9 have a slightly widened shape (a shape slightly protruding outward in the left-right direction). There are slightly widened folding portions 42 at the bottom surface 2 side portions of both side surfaces 5. This is due to the repulsive force of the bottom gusset 21 of the expanded flat bag 9 trying to return to its original state when expanded. Even with such widened folding portions 42 existing, since the side gussets 35 are forcibly folded from both side surfaces 5 of the expanded flat bag 9 by the operations of the above-described opening / closing plates 13 and side folding plates 11, the side gussets 35 are surely formed.

[0074] Also, at Station C, the rack 87 for the bottom folding plate 12 is driven slightly after the start of the operation of the side folding plate 11, so that the bottom folding plate 12 starts the insertion operation (pushing-in operation) into the bag. Specifically, when the side folding plate 11 starts the insertion (pushing-in) and the opening / closing plate 13 starts to move to the proximity state, the bottom gusset 21 is naturally folded inward into the bag along the originally existing valley fold 25. During this folding process, the bottom folding plate 12 moves from the preparation position P3 to the folding position P4 toward the central portion of the bottom gusset 21. That is, the bottom folding plate 12 starts the insertion operation into the bag after the side folding plate 11 contacts the side portion of the flat bag 9 and before the side folding plate 11 finishes the insertion operation and switches to the separation operation. The bottom folding plate 12 detaches from between the pair of opening / closing plates 13 before the opening / closing plate 13 completely reaches the proximity state. Thereby, the bottom gusset 21 is formed.

[0075] At this time, four folds (the V-shaped portion 25b of the valley fold 25, see FIG. 4) that did not exist in the flat bag 9 before it becomes the square-bottom packaging bag 1 are newly formed on the bottom surface 2. Further, the perpendicular lines extending from both ends 25c of the straight portion 25a of the valley fold 25 that the bottom folding plate 12 contacts toward the hypotenuse 42a of the folding portion 42 change from valley folds to mountain folds. That is, they are folded on the side opposite to the folding direction in the flat bag 9. The new folds along this perpendicular line are creased into a predetermined shape by the opening / closing plate 13, the side folding plate 11, and the bottom folding plate 12. That is, the new folds along the perpendicular line are held by the operations of the opening / closing plate 13, the side folding plate 11, and the bottom folding plate 12.

[0076] In a state where the pair of opening and closing plates 13 has reached the proximity state, the side folding plate 11 and the bottom folding plate 12 are detached from the square-bottom packaging bag 1. Therefore, in a state where the gusset forming process at station C is completed, the side gussets 35 and the bottom gusset 21 are sandwiched between the pair of opening and closing plates 13. When the gusset forming process is completed, the rotary table 71 rotates approximately 45°, and the opening and closing plates 13 that support the square-bottom packaging bag 1 move to station D.

[0077] At station D, the opening and closing plates 13 in the proximity state are sandwiched from above and below by the temperature plates 92. At this time, by heating and pressing the square-bottom packaging bag 1 with the temperature plates 92, folds such as the gussets 21, 35 and the folding part 42 are imparted. That is, at station D, a pressing process is performed. When the heating and pressing at station D are completed, the rotary table 71 rotates approximately 45°, and the opening and closing plates 13 that support the square-bottom packaging bag 1 move to station E.

[0078] At station E, the opening and closing plates 13 in the proximity state are sandwiched from above and below by the temperature plates 92, and a portion corresponding to the peripheral edge of the side surface 5 of the square-bottom packaging bag 1 is joined to form the column joint portion 31. In other words, at station E, a column joint portion forming process is performed. When the formation of the column joint portion 31 is completed, the rotary table 71 rotates approximately 45°, and the opening and closing plates 13 that support the square-bottom packaging bag 1 move to station F.

[0079] At station F, similar to station D, the opening and closing plates 13 in the proximity state are sandwiched from above and below by the temperature plates 92 and cooled to impart a stronger fold. That is, at station F, the pressing process is performed again. When the cooling and pressing at station F are completed, the rotary table 71 rotates approximately 45°, and the opening and closing plates 13 that support the square-bottom packaging bag 1 move to station G.

[0080] At station G, the formed square-bottom packaging bag 1 is collected. At station G, first, the vicinity of the bottom of the square-bottom packaging bag 1 is adsorbed by a vacuum suction pad provided on the recovery arm 101. Next, as the recovery arm 101 moves along the radial direction of the rotary table 71, the folded square-bottom packaging bag 1 is moved to the transfer rotary table 102. Next, the vacuum suction pad is detached. As a result, the square-bottom packaging bag 1 is transferred from the rotary table 71 to the transfer rotary table 102. Thus, the production of the square-bottom packaging bag 1 is completed. The square-bottom packaging bag 1 delivered to the transfer rotary table 102 is further supplied to the filling device 53 in the subsequent process. When the delivery of the square-bottom packaging bag 1 at station G is completed, the opening / closing plate 13 moves back to station A via station H and repeats the above-described process.

[0081] (Function, Effect) Next, the functions and effects of the above-described method for manufacturing a square-bottom packaging bag, the manufacturing apparatus 52 for a square-bottom packaging bag, the method for manufacturing a package, and the manufacturing apparatus 50 for a package will be described. According to the method for manufacturing a square-bottom packaging bag of the present embodiment, the square-bottom packaging bag 1 is manufactured from the flat bag 9 through the expansion process and the gusset formation process. In the expansion process, by expanding the flat bag 9 from the inside of the bag, the opening cross-sectional shape of the flat bag 9 is made square, and the flat bag 9 can be held from the inside of the bag. Therefore, in the subsequent gusset formation process after the expansion process, the side gusset 35 and the bottom gusset 21 can be formed while holding the flat bag 9. In addition, since the operation of expanding the flat bag 9 and the operation of holding it can be performed in the same process, productivity can be improved. Therefore, it is possible to clarify the method of holding the flat bag 9 when manufacturing the square-bottom packaging bag 1 having three-sided gussets from the flat bag 9 having the bottom gusset 21, and to provide a method for manufacturing a square-bottom packaging bag with improved productivity.

[0082] The expanding step preferably includes a plate inserting step and a plate separating step. In the plate inserting step, a pair of opening / closing plates 13 are inserted into the interior of the flat bag 9. In the plate separating step, the pair of opening / closing plates 13 are separated from each other along the thickness direction of the flat bag 9. In this way, by separating the pair of opening / closing plates 13, the flat bag 9 can be opened, and in the opened state, the flat bag 9 can be held from the inside of the bag by the opening / closing plates 13. In the gusset forming step, by pushing a folding plate between the pair of opening / closing plates 13 while holding the flat bag 9, side gussets 35 and bottom gussets 21 are formed. Therefore, a triple gusset that protrudes inward of the bag can be formed by a simple method.

[0083] The method for manufacturing a square-bottom packaging bag preferably includes a column joint forming step of forming a column joint 31. Since the column joint 31 functions as a column structure that supports the square-bottom packaging bag 1, the self-standing property of the square-bottom packaging bag 1 can be improved as compared with the case where the square-bottom packaging bag 1 is formed without providing the column joint 31. In addition, the column joint 31 can be easily formed by joining the peripheral edges of the side gussets 35. Therefore, the column joint 31 can be formed while maintaining high productivity without complicating the manufacturing process.

[0084] The method for manufacturing a square-bottom packaging bag preferably includes a flat bag manufacturing step. In the flat bag manufacturing step, the flat bag 9 can be easily manufactured by folding a roll-shaped film 16 a plurality of times. In the flat bag manufacturing step, a side joint 33, a bottom joint 22, and an inclined joint 34 are formed. Since the inclined joint 34 is formed in the flat bag 9, when expanding the flat bag 9 in the expanding step, by starting from the inclined joint 34, the corners and the four sides of the square-bottom packaging bag 1 can be easily positioned. Therefore, the manufacturability of the square-bottom packaging bag 1 can be improved. In addition, by positioning the corners of the square-bottom packaging bag 1, the shape of the bottom surface 2 of the square-bottom packaging bag 1 can be made into a square shape as designed. Therefore, it is possible to manufacture a square-bottom packaging bag 1 with suppressed occurrence of distortion and wrinkles on the bottom surface 2, improved self-standing property, and improved appearance quality.

[0085] In the method for manufacturing a gusseted bottom packaging bag, it is preferable that the gusseted bottom packaging bag manufacturing process is continuously performed after the flat bag manufacturing process. In this case, the labor and time loss for transporting the flat bag 9 can be reduced. As a result, the production efficiency of the entire method for manufacturing a gusseted bottom packaging bag combining the flat bag manufacturing process and the gusseted bottom packaging bag manufacturing process can be improved. Also, for example, after the completion of the flat bag manufacturing process, there is no need to separately provide a space for storing the formed flat bag 9. Therefore, the apparatus for manufacturing the gusseted bottom packaging bag 1 can be miniaturized and space-saving.

[0086] According to the manufacturing apparatus 52 for a gusseted bottom packaging bag of the present embodiment, the manufacturing apparatus 52 for a gusseted bottom packaging bag includes a pair of openable and closable open / close plates 13, a side folding plate 11, and a bottom folding plate 12. By opening and closing the pair of open / close plates 13, the flat bag 9 can be expanded and held in a state where the cross-section is square-shaped. Therefore, the expanding process can be carried out with a simple configuration for opening and closing the pair of open / close plates 13. The side folding plate 11 forms a side gusset 35 that protrudes inward of the bag by entering between the open / close plates 13. The bottom folding plate 12 forms a bottom gusset 21 that protrudes inward of the bag by entering between the open / close plates 13. Therefore, the gusset forming process can be carried out with a simple configuration using the side folding plate 11 and the bottom folding plate 12. Therefore, it is possible to clarify the method for holding the flat bag 9 when manufacturing the gusseted bottom packaging bag 1 having a bottom gusset 21 from the flat bag 9 having a triple gusset, and to provide the manufacturing apparatus 52 for a gusseted bottom packaging bag with improved productivity.

[0087] According to the method for manufacturing a package of the present embodiment, after the gusseted bottom bag 1 is manufactured by the method for manufacturing a gusseted bottom bag (gusseted bottom bag manufacturing step), a filling step is continuously performed. Thereby, compared with the case where the gusseted bottom bag manufacturing step and the filling step are separate steps that are not continuous, the labor and time loss for transporting the gusseted bottom bag 1 can be reduced. In particular, when shipping as the package 10 filled with the content C1 in the gusseted bottom bag 1, by performing the gusseted bottom bag manufacturing step and the filling step in a series of flows, it is possible to make the package 10 in a state where it can be shipped with a minimum space without separately determining a space for storage or the like. Therefore, the time required from the manufacture of the gusseted bottom bag 1 to the manufacture of the package 10 that can be shipped can be shortened, and the space required for manufacture can be reduced. Therefore, while clarifying the method for holding the flat bag 9 when manufacturing the gusseted bottom bag 1 having three-sided gussets from the flat bag 9 having a bottom gusset 21, it is possible to provide a method for manufacturing a package with improved productivity.

[0088] According to the manufacturing apparatus 50 for a package of the present embodiment, since it has a filling apparatus 53 for filling the content C1 into the gusseted bottom bag 1, the manufacture of the gusseted bottom bag 1 and the filling of the content C1 can be completed in a series of lines. Therefore, the entire manufacturing apparatus combining the apparatus for manufacturing the gusseted bottom bag 1 and the filling apparatus 53 can be miniaturized. Also, compared with the case where the gusseted bottom bag 1 is once stored after manufacturing the gusseted bottom bag 1, or the case where the apparatus for manufacturing the gusseted bottom bag 1 and the filling apparatus 53 are installed at separate locations, the time and labor required for manufacturing and filling can be reduced. Thereby, the efficiency in the manufacturing apparatus 50 for a package can be improved. Therefore, while clarifying the method for holding the flat bag 9 when manufacturing the gusseted bottom bag 1 having three-sided gussets from the flat bag 9 having a bottom gusset 21, it is possible to provide a manufacturing apparatus 50 for a package with improved productivity.

[0089] (First Modification Example) Next, a first modification example according to the present invention will be described. FIG. 16 is an external perspective view of the gusseted bottom bag 1 according to the first modification example. The first modification example is different from the above-described first embodiment in that the lower end portion 31a of the column joint portion 31 is provided at a distance from the bottom joint portion 22.

[0090] As shown in FIG. 16, in the square-bottomed packaging bag 1 of the first modified example, the lower end portion 31a of the column joint portion 31 is not connected to the bottom. In other words, in the column joint portion forming step of the first modified example, in the square-bottomed packaging bag 1 in a state where the front surface 3 and the rear surface 4 are in close contact (closed state, see FIG. 9), the inner surfaces of the front surface 3 and the left side surface 7 face each other at an edge portion that does not overlap with the bottom joint portion 22, and this portion is heated and pressed. As a result, the column joint portion 31 is formed along each of the boundary lines L1, L2, L3, L4 and on the opening 8 side rather than the bottom joint portion 22.

[0091] According to the first modified example, compared with the first embodiment in which the column joint portion 31 and the bottom joint portion 22 are connected and formed, the generation of wrinkles and the distortion of the bottom surface 2 at the corner where the bottom joint portion 22 and the column joint portion 31 overlap can be suppressed. Therefore, the appearance quality and self-standing property of the square-bottomed packaging bag 1 can be improved. Further, at the corner of the bottom joint portion 22 that overlaps with the column joint portion 31, there is no need to join the bottom joint portions 22 to each other. For this reason, the labor of separately applying a heat-sealing agent or the like to the corners of the bottom joint portion 22 and joining the outer surfaces of the film 16 can be reduced, and the manufacturing method can be simplified. Further, the column joint portion 31 may not be provided at the upper end portion of the square-bottomed packaging bag 1 where the opening 8 is located. The opening 8 is a portion that is closed after filling the square-bottomed packaging bag 1 with the content C1. Even if the column joint portion 31 is provided up to the upper end portion of the square-bottomed packaging bag 1, the column joint portion 31 at the upper end portion does not contribute to the improvement of the self-standing property of the square-bottomed packaging bag 1. Therefore, even when the column joint portion 31 is not provided at the upper end portion of the square-bottomed packaging bag 1, the self-standing property of the square-bottomed packaging bag 1 is improved.

[0092] (Second Modified Example) Next, a second modified example according to the present invention will be described. FIG. 17 is an external perspective view of the square-bottomed packaging bag 1 according to the second modified example. The second modified example is different from the first embodiment described above in that the square-bottomed packaging bag 1 is formed without having the column joint portion 31 and the side joint portion 33 has the fixed seal portion 40.

[0093] As shown in FIG. 17, the square-bottom packaging bag 1 of the second modified example is formed without having column joints 31 at positions corresponding to the respective boundary lines L1, L2, L3, and L4. Specifically, the end portion of the left side surface 7 of the square-bottom packaging bag 1 located on the front surface 3 side is connected to the left side of the front surface 3. That is, the film 16 is bent by approximately 90° along the first boundary line L1 along the left side of the front surface 3 in the vertical direction, whereby the front surface 3 and the left side surface 7 are continuously formed. Similarly, the film 16 is bent by approximately 90° along the second boundary line L2 along the right side of the front surface 3, whereby the front surface 3 and the right side surface 6 are continuously formed. The film 16 is bent by approximately 90° along the third boundary line L3 along the left side of the rear surface 4, whereby the rear surface 4 and the left side surface 7 are continuously formed. The film 16 is bent by approximately 90° along the fourth boundary line L4 along the right side of the rear surface 4, whereby the rear surface 4 and the right side surface 6 are continuously formed.

[0094] Furthermore, the square-bottom packaging bag 1 of the second modified example has a fixed seal portion 40. The fixed seal portion 40 is provided at the lower end portion 33b of the side joint portion 33. The fixed seal portion 40 joins the side joint portion and the side surface 5. The fixed seal portion 40 fixes the side joint portion 33 along the side surface 5. Such a fixed seal portion 40 is formed by a fixed seal portion forming step, which is performed, for example, after a gusset forming step, in the method for manufacturing a square-bottom packaging bag. Before the fixed seal portion forming step, a side joint portion bending step may be provided. In the side joint portion bending step, in order to join the side joint portion 33 and the side surface 5, the side joint portion 33 is folded down toward the side surface 5 side so as to be in close contact with the side surface 5 over the entire length from the lower end portion 33b to the upper end portion. Also, the square-bottom packaging bag manufacturing apparatus 52 has a fixed seal portion forming apparatus (not shown) for forming the fixed seal portion 40. Further, it may have a side joint portion bending apparatus (not shown) for bending the side joint portion 33.

[0095] According to the second modification example, since there is no need to provide a column joint forming step, the number of steps in the method for manufacturing the gusseted bottom packaging bag can be reduced. Therefore, the method for manufacturing the gusseted bottom packaging bag and the manufacturing apparatus 52 for the gusseted bottom packaging bag can be simplified. Further, since the side joint portion 33 has the fixed seal portion 40, it is possible to suppress the side joint portion 33 from protruding outward of the bag with respect to the side surface 5. Therefore, the appearance of the gusseted bottom packaging bag 1 can be improved as compared with the case where the side joint portion 33 protrudes with respect to the side surface 5. In the second modification example, a column joint portion 31 may be provided together with the fixed seal portion 40.

[0096] (Third Modification Example) Next, a third modification example according to the present invention will be described. FIG. 18 is a plan view of the folding device 80A according to the third modification example. In the third modification example, as shown in FIG. 18, a bottom surface pushing device 88 is provided on the radially outer side of the position of the station B of the rotary table 71. The bottom surface pushing device 88 includes a pushing portion having a rectangular pushing surface slightly smaller than the bottom surface 2 of the flat bag 9 at a position facing the bottom surface 2 of the expanded flat bag 9. The bottom surface pushing device 88 has a function of pushing the bottom surface 2 of the flat bag 9 held and expanded by the opening and closing plate 13 at the station B toward the center in the radial direction of the rotary table 71 by moving the pushing portion toward the center in the radial direction of the rotary table 71. When the rotary table 71 rotates and the opening / closing plate 13 moves from station A to station B, the flat bag 9 supported from the inner side of the bag between the pair of opening / closing plates 13 in the proximity state may shift radially outward due to centrifugal force. Also, in the expanding process at station B, the flat bag 9 may shift radially outward when the pair of opening / closing plates 13 separate. In this third modification, the pushing portion of the bottom surface pushing device 88 pushes the bottom surface 2 of the flat bag 9 toward the center of the rotary table 71, and the bottom surface 2 of the flat bag 9 is held by the pair of opening / closing plates 13 in the separated state and the square-shaped pushing portion. Thereby, the shift of the flat bag 9 radially outward can be prevented. Also, the shape of the bottom surface 2 can be adjusted to surely form a square plane. Thereby, in the subsequent gusset forming process at station C, a gusset can be formed more surely.

[0097] As described above, the embodiments of the present invention have been explained. However, the technical scope of the present invention is not limited to the content of the above embodiments, and various changes can be made to each component, deletion can be performed, or the combination of each component can be changed beyond the embodiments without departing from the gist of the present invention. For example, in the above-described embodiment of the flat bag manufacturing process, the laminated film having a heat-sealing layer on one side where a plurality of films are laminated may contain a paper material or may be a laminate of a single-system material. Also, instead of the laminated film, a single-layer film may be used, or a film having a heat-sealing layer on both sides may be used. Also, in the above-described flat bag manufacturing process, since the flat bag 9 having the bottom gusset 21 is manufactured by bending the film 16 fed out from one raw material roll 54 into a W shape, it is preferable that there is one raw material roll to be prepared. However, the flat bag 9 may be manufactured from a plurality of raw material rolls, such as feeding out the film forming the flat portion 15 and the film forming the bottom gusset 21 from different raw material rolls.

[0098] Further, for example, the manufacturing apparatus 52 for the gusseted bottom packaging bag forms the column joint 31 with a press device 90 provided at a position corresponding to station E of the rotary table 71. However, the press device may be provided at another station of the rotary table 71, or may be performed at a location other than the stations of the rotary table 71. Specifically, for example, at stations D and E, after heating and pressing with the temperatures of the pair of temperature plates 92 being the same or different, cooling is performed at station F to impart folds such as the gussets 21, 35 and the folding portions 42 of the gusseted bottom packaging bag 1. Then, a press device may be provided at the station of the transfer rotary table 102 in FIG. 10 for heating and cooling to form the column joint 31. At the station of the rotary table 102, since the opening and closing plate 13 does not exist inside the gusseted bottom packaging bag 1, it is preferable because the column joint 31 that more reliably joins the inner surfaces of the bag can be formed. Also, the folding device 80 in the manufacturing apparatus 52 for the gusseted bottom packaging bag can be configured such that, instead of the link mechanism, two side folding plates are fixed to a single support shaft and opened and closed in the same manner as scissors.

[0099] Further, the manufacturing apparatus 52 for the gusseted bottom packaging bag may be provided with a discharge device for collecting defective products, for example, when a defect occurs at station H. In this case, a camera or other measuring device for detecting defects may be separately provided at a predetermined station upstream of station H. Also, in the manufacturing apparatus 52 for the gusseted bottom packaging bag, one pair of opening and closing plates 13 is provided at each station of the rotary table 71, but a plurality of them may be provided. Further, the manufacturing apparatus 52 for the gusseted bottom packaging bag is a so-called rotary manufacturing apparatus having a rotary table 71. However, without using a rotary table, a pair of opening and closing plates 13 that receive the flat bag 9 move linearly or curvilinearly along a rail or the like, and after going through various processes, after the delivery of the gusseted bottom packaging bag is completed, it may be a non-rotary apparatus that circulates to receive the flat bag 9 again.

[0100] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the components in the above-described embodiments with well-known components, and the above-described embodiments may also be combined as appropriate.

Industrial Applicability

[0101] The present invention can be used in a method for manufacturing a gusseted bottom packaging bag that manufactures a gusseted bottom packaging bag from a flat bag having a bottom gusset, an apparatus for manufacturing a gusseted bottom packaging bag, a method for manufacturing a package, and an apparatus for manufacturing a package.

Explanation of Signs

[0102] 1 Gusseted bottom packaging bag 8 Opening 9 Flat bag 10 Package 11 Side folding plate (folding plate) 12 Bottom folding plate (folding plate) 13 Opening / closing plate 16 Film 21 Bottom gusset 22 Bottom joint 31 Column joint 33 Side joint 34 Inclined joint 35 Side gusset 50 Apparatus for manufacturing a package 52 Apparatus for manufacturing a gusseted bottom packaging bag (apparatus for manufacturing a gusseted bottom packaging bag) 53 Filling device C1 Contents

Claims

1. A method for manufacturing a gusseted bottom packaging bag having a three-sided gusset from a flat bag formed from a film and having a pair of flat portions and a bottom gusset formed between the pair of flat portions, wherein the flat bag further has a pair of bottom joints formed by joining the pair of flat portions and the peripheral portion of the bottom gusset, and a pair of side joints formed on the side portions of the flat bag, in each of the pair of flat portions, at a pair of corners where the pair of side joints and the bottom joints intersect, a pair of inclined joints are formed by obliquely connecting between the pair of side joints and the bottom joints, the method for manufacturing the gusseted bottom packaging bag includes, a spreading step of spreading the flat bag from the inside of the bag so that the opening cross-section of the flat bag has a rectangular shape, after the spreading step, a gusset forming step of forming side gussets and forming the bottom gusset of the gusseted bottom packaging bag having a different length from the bottom gusset of the flat bag while holding the formed side gussets, characterized by comprising: the spreading step includes, a plate insertion step of inserting a pair of opening / closing plates having a rectangular shape and arranged in parallel facing each other in the thickness direction of the flat bag and in a state of being close to each other into the inside of the flat bag, a plate separation step of separating the pair of opening / closing plates inserted into the inside of the flat bag from each other along the thickness direction of the flat bag, characterized by comprising: in a direction orthogonal to the direction in which the pair of opening / closing plates are inserted into the inside of the flat bag and orthogonal to the thickness direction of the flat bag, the width dimension of the pair of opening / closing plates is equal to the dimension between the respective end portions on the bottom joint side of the pair of inclined joints, in the gusset forming step, a folding plate is pushed into between the pair of opening / closing plates from the outside of the bag toward the inside of the bag, the pair of opening / closing plates are brought close to each other again according to the insertion depth of the folding plate, and after inserting to a predetermined depth, the folding plate is pulled out toward the outside of the bag with the pair of opening / closing plates in a closed state, thereby forming the side gussets and the bottom gusset, a method for manufacturing a gusseted bottom packaging bag.

2. The method for manufacturing a gusseted bottom packaging bag according to claim 1, further comprising a column joint forming step of forming column joints extending along the four corners of the opening cross-section by joining the peripheral portions of the side gussets after the gusset forming step.

3. Before the expanding step, there is a flat bag manufacturing step of manufacturing the flat bag. In the flat bag manufacturing step, the pair of side joining portions and the pair of bottom joining portions formed at the bottom of the flat bag are formed, and the pair of inclined joining portions are formed on each of the pair of flat portions. The method for manufacturing a gusseted bottom packaging bag according to claim 1 or claim 2.

4. The method for manufacturing a gusseted bottom packaging bag according to claim 3, wherein the expanding step is continuously performed after the flat bag manufacturing step.

5. A manufacturing apparatus for a gusseted bottom packaging bag for manufacturing the gusseted bottom packaging bag by the method for manufacturing a gusseted bottom packaging bag according to any one of claims 1 to 4, The pair of opening and closing plates that can be opened and closed so as to expand the flat bag from the inside of the bag so that the cross section of the flat bag has a square shape, A side folding plate that enters between the pair of opening and closing plates and forms the side gusset, A bottom folding plate that enters between the pair of opening and closing plates and forms the bottom gusset, A manufacturing apparatus for a gusseted bottom packaging bag, comprising:

6. After the step of implementing the method for manufacturing a gusseted bottom packaging bag according to any one of claims 1 to 4, continuously, there is a filling step of filling the manufactured gusseted bottom packaging bag with contents to manufacture a package. A method for manufacturing a package.

7. A manufacturing apparatus for a package for manufacturing the package by the method for manufacturing a package according to claim 6, A manufacturing apparatus for a package, comprising a filling device for filling the gusseted bottom packaging bag with contents.

8. After the gusset forming step, there is further a fixed seal portion forming step of forming a fixed seal portion for fixing the pair of side joining portions formed on the side portion of the flat bag along the side surface of the gusseted bottom packaging bag in which the side gusset is formed. The method for manufacturing a gusseted bottom packaging bag according to any one of claims 1 to 4.

9. The method for manufacturing a gusseted bottom packaging bag according to claim 8, wherein the fixed seal portion is provided at the lower end portion of the side joining portion.

10. After the expanding step, the bottom surface of the flat bag held and expanded by the pair of opening and closing plates provided on the outer peripheral portion of the rotating table is pushed toward the center in the radial direction of the rotating table. The method for manufacturing a gusseted bottom packaging bag according to any one of claims 1 to 4, 8, and 9.

11. The manufacturing apparatus for a square-bottom packaging bag according to claim 5, further comprising a bottom pressing and opening device that presses the bottom surface of the flat bag, which is held and expanded by the pair of opening and closing plates provided on the outer peripheral portion of the rotary table, toward the center in the radial direction of the rotary table.

12. further comprising a pressing device that forms a column joint portion extending along the four corners of the opening cross section by joining the peripheral portions of the side gussets, wherein the pressing device is provided on a transfer rotary table of a recovery device, wherein the transfer rotary table is provided on the downstream side of the side folding plate and the bottom folding plate in the rotation direction of the rotary table provided with the pair of opening and closing plates, of the manufacturing apparatus for a square-bottom packaging bag according to claim 5 or 11.

Images