Web forming device and forming method, and bag making machine for double bag

Abstract

A web former forms a double-layer web folded in half and including a first web and a second web. The web former includes a first tension adjuster configured to control tension of the first web being fed in a longitudinal direction of the first web, and a second tension adjuster configured to control tension of the second web being fed in a longitudinal direction of the second web independently of the first tension adjuster. The web former includes a guide disposed downstream of the first and second tension adjusters to guide the first web and the second web downstream while superposing the first web and the second web on each other, and a single triangular plate disposed downstream of the guide to fold the first and second webs superposed by the guide, in half along a fold line extending in the longitudinal direction of the first and second webs.

Description

TECHNICAL FIELD

[0001] The present application relates to a web former and a method for forming a double-layer web folded in half, such as a double-layer gusset web, for use in making double-layer bags. The present application also relates to a bag making apparatus for successively making double-layer bags.BACKGROUND

[0002] Double-layer bags are well-known, for example, as disclosed in Patent Documents 1 and 2. A double-layer bag at least includes two double-layer panels facing each other. A storage space is formed by and between these two double-layer panels. Each of the double-layer panels consists of an inner panel part and an outer panel part which are superposed on each other.

[0003] The double-layer bags disclosed in Patent Documents 1 and 2 each further include a pair of double-layer gussets. Each of the double-layer gussets also has a double-layer structure and thus consists of an outer gusset part and an inner gusset part which have been folded in half with themselves superposed on each other.

[0004] Patent Document 1 discloses a bag making apparatus for successively making such double-layer bags. The bag making apparatus includes a gusset former that forms a double-layer gusset web from which the double-layer gussets will be formed. The gusset former unwinds an outer gusset web (for the outer gusset parts) and an inner gusset web (for the inner gusset parts) from their respective rolls, and superposes them on each other. The gusset former then folds the superposed outer gusset web and inner gusset web in half along a fold line extending in their longitudinal direction, thereby forming the double-layer gusset web.

[0005] Patent Document 1 discloses folding the superposed outer gusset web and inner gusset web in half with only one triangular plate. This configuration, which folds two webs with a single triangular plate, typically may cause one of the two webs to sag or meander. It is therefore difficult to fold the outer gusset web and the inner gusset web with a neat alignment. If the double-layer gusset web is poorly finished, the finished bag, of course, will have poor quality.CITATION LIST PATENT DOCUMENT

[0006] Patent Document 1: JPA 2016-141427 Patent Document 2: JPA 2022-7011SUMMARY

[0007] The present application provides a web former and a web forming method for forming a well-finished double-layer web folded in half, and a bag making apparatus including said web former.

[0008] According to the present application, there is provided a web former for use in making double-layer bags and for forming a double-layer web folded in half and including a first web and a second web, the web former including: a first tension adjuster configured to control tension of the first web being fed in a longitudinal direction of the first web; a second tension adjuster configured to control tension of the second web being fed in a longitudinal direction of the second web independently of the first tension adjuster; a guide disposed downstream of the first and second tension adjusters to guide the first web and the second web downstream while superposing the first web and the second web on each other; and a single triangular plate disposed downstream of the guide to fold the first and second webs superposed by the guide, in half along a fold line extending in the longitudinal direction of the first and second webs.

[0009] For example, the web former may be a gusset former for forming a double-layer gusset web as the double-layer web, the double-layer gusset web comprising an outer gusset web as the first web and an inner gusset web as the second web.

[0010] The first tension adjuster may further be configured to switch the first web from continuous feed to intermittent feed. The second tension adjuster may further be configured to switch the second web from continuous feed to intermittent feed.

[0011] The first tension adjuster may be a first dancer mechanism. The second tension adjuster may be a second dancer mechanism. The first dancer mechanism may include a first dancer roller for engaging with the first web to apply tension to the first web. The second dancer mechanism may include a second dancer roller for engaging with the second web to apply tension to the second web.

[0012] For example, the guide may be a guide roller.

[0013] The web former may further include a temporary fixer disposed downstream of the triangular plate and configured to temporarily fix the first web and the second web to each other.

[0014] According to the present application, there is also provided a bag making apparatus for successively making double-layer bags each comprising a first double-layer panel, a second double-layer panel, and a double-layer gusset, the bag making apparatus comprising: an intermittent feeder configured to intermittently feed a first outer panel web, a first inner panel web, a second outer panel web, and a second inner panel web in a longitudinal direction thereof; a pair of superposing rollers for superposing the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel web on each other in this order; the web former as the above-described gusset former, the web former being configured to supply the double-layer gusset web to interpose the double-layer gusset web between the first inner panel web and the second inner panel web in the longitudinal direction when the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel are superposed on each other at the pair of superposing rollers; at least one heat sealer disposed downstream of the pair of superposing rollers and configured to heat-seal the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web during every intermittent feed cycle; and a cross cutter disposed downstream of the at least one heat sealer and configured to cross-cut the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web in a width direction thereof during every intermittent feed cycle to shape a double-layer bag wherein the first double-layer panel is formed from the first outer panel web and the first inner panel web, the second double-layer panel is formed from the second outer panel web and the second inner panel web, and the double-layer gusset is formed from the double-layer gusset web.

[0015] The bag making apparatus may further include a spout attacher disposed downstream of the pair of superposing rollers and upstream of the at least one heat sealer, and configured to attach a spout to the first outer panel web and the first inner panel web superposed on each other during every intermittent feed cycle. The spout attacher may include: a plurality of guide rollers for temporarily separating the second outer panel web, the second inner panel web, and the double-layer gusset web from the first outer panel web and the first inner panel web to create a temporary separation zone; a temporary fixing unit disposed in the temporary separation zone and configured to temporarily fix the first outer panel web and the first inner panel web to each other; a punching unit disposed downstream of the temporary fixing unit in the temporary separation zone and configured to punch a hole for the spout in the first outer panel web and the first inner panel web; and an attaching unit disposed downstream of the punching unit in the temporary separation zone and configured to insert the spout into the hole and attach the inserted spout to the first outer panel web and the first inner panel web by heat-sealing.

[0016] The web former may further include a puncher configured to punch a hole for heat-sealing in the double-layer gusset web, and the at least one heat sealer may be configured to heat-seal the first and second inner panel webs to each other through the hole for heat-sealing.

[0017] Furthermore, according to the present application, there is also provided a web forming method for forming a double-layer web folded in half and including a first web and a second web for making double-layer bags, the method including: feeding the first web in a longitudinal direction of the first web; feeding the second web in a longitudinal direction of the second web; controlling tension of the first web using a first tension adjuster; controlling tension of the second web using a second tension adjuster independently of the controlling the tension of the first web using the first tension adjuster; guiding the first web and the second web downstream while superposing the first and second webs on each other using a guide located downstream of the first and second tension adjusters, and folding the superposed first and second webs in half along a fold line extending in the longitudinal direction of the first and second webs using a single triangular plate located downstream of the guide, to interpose the folded first web between the folded second web.

[0018] The first web may include a first surface layer and a second surface layer having a lower melting point than a melting point of the first surface layer, and the second web may have a lower melting point than the melting point of the first surface layer. The first web and the second web may be folded in half along the fold line by the triangular plate to contact the second surface layer with the second web.

[0019] The first web may be unwound from a first roll and continuously fed in the longitudinal direction thereof. The second web may be unwound from a second roll and continuously fed in the longitudinal direction thereof. The first web may be switched from continuous feed to intermittent feed by the first tension adjuster. The second web may be switched from continuous feed to intermittent feed by the second tension adjuster.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [Fig. 1] Fig. 1A illustrates an example double-layer bag, and Fig. 1B is a partial sectional view of the bag in Fig. 1A. [Fig. 2] Fig. 2A is a schematic side view of an upstream section of an example bag making apparatus, and Fig. 2B is a partial plan view of Fig. 2A. [Fig. 3] Fig. 3A is a schematic plan view of a midstream section of the example bag making apparatus, and Fig. 3B is a side view of Fig. 3A. [Fig. 4] Figs. 4A and 4B each illustrate an example point sealed section, and Fig. 4C illustrates an example of attaching a spout. [Fig. 5] Fig. 5A is a schematic plan view of a downstream section of the example bag making apparatus, and Fig. 5B is a side view of Fig. 5A. [Fig. 6] Fig. 6A illustrates an example double-layer bag, Fig. 6B is a partial sectional view of webs superposed on each other, and Figs. 6C and 6D illustrate example heat seal bars. [Fig. 7] Fig. 7A is a schematic plan view of an example gusset former, and Fig. 7B is a partial side view of Fig. 7A. [Fig. 8] Fig. 8 is a detailed view of a region Q in Fig. 7. [Fig. 9] Fig. 9A is a view as viewed from an arrow S1 in Fig. 7B, Fig. 9B is a view as viewed from an arrow S2 in Fig. 7B, Fig. 9C is a view as viewed from an arrow F in Fig. 7A, Fig. 9D is an enlarged view as viewed from an arrow J in 9C, and Fig. 9E is an enlarged view of a region G in Fig. 7A. [Fig. 10] Fig. 10A is a schematic plan view of a gusset former according to the related art, and Fig.10B is a sectional view of a gusset web formed by the gusset former in Fig. 10A according to the related art. DETAILED DESCRIPTION

[0021] The embodiments of the present application will now be described with reference to the drawings. The following embodiments are merely examples of the present inventions.

[0022] Fig. 1A illustrates an example double-layer bag 1. The double-layer bag 1 includes two double-layer panels 10 facing each other. As illustrated in Fig. 1B, which is a sectional view, each of the double-layer panels 10 consists of an outer panel part 100 and an inner panel part 101 superposed on each other. A storage space is formed by and between these two double-layer panels 10. The two inner panel parts 101 face each other and are interposed between the two outer panel parts 100.

[0023] The double-layer bag 1 further includes two double-layer gussets 11. The two double-layer gussets 11 form a pair, are folded to be interposed between the two double-layer panels 10, and extend along the opposite side edges of the double-layer panels 10. That is, the example double-layer gussets 11 function as side gussets to expand the storage space of the bag 1.

[0024] As illustrated in Fig. 1B, each of the double-layer gussets 11 consists of an outer gusset part 110 and an inner gusset part 111 superposed on each other. The outer gusset part 110 is located on the outside of the bag 1, whereas the inner gusset part 111 is located on the inside of the bag 1. When the double-layer gusset 11 is folded as illustrated in Fig. 1B, the folded outer gusset part 110 is interposed between the folded inner gusset part 111.

[0025] The double-layer bag 1 further includes a spout 12. The spout 12 is attached to one of the double-layer panels 10. Contents can be filled into or taken out of the storage space through the spout 12.

[0026] To ensure airtightness, the double-layer bag 1 includes first sealed sections 13 formed along the opposite side edges of the bag 1 and second sealed sections 14 formed along the top and bottom edges of the bag 1. In the first sealed sections 13 and the second sealed sections 14, each inner panel part 101 is welded to the adjacent outer panel part 100 and the adjacent inner gusset parts 111, and the outer gusset part 110 and the inner gusset part 111 are welded to each other. Furthermore, in the regions of the second sealed sections 14 where the double-layer gusset 11 is absent, the two inner panel parts 101 are welded to each other.

[0027] Similar to Patent Document 2, the double-layer bag 1 further includes third sealed sections 15 extending obliquely relative to the opposite side edges and the top and bottom edges of the bag 1. The third sealed sections 15 each extend obliquely from the end of the folded edge (inner edge) of the double-layer gusset 11 to the first sealed section 13. Also, in the respective third sealed sections 15, each inner panel part 101 is welded to the adjacent outer panel part 100 and the adjacent inner gusset part 111, and the outer gusset part 110 and the inner gusset part 111 are welded to each other.

[0028] It should be noted that the facing surfaces of the respective folded outer gusset parts 110 are not welded to each other.

[0029] An example bag making apparatus for successively making the above example double-layer bags 1 will now be described.

[0030] Fig. 2A schematically illustrates an upstream section of an example bag making apparatus. Four rolls 20', 21', 30' and 31' are installed. The roll 20' is formed by a first outer panel web 20 being wound, from which the outer panel part 100 of one of the two double-layer panels 10 (first double-layer panel) of the bag 1 will be formed. The roll 21' is formed by a first inner panel web 21 being wound, from which the inner panel part 101 of the first double-layer panel 10 will be formed. The roll 30' is formed by a second outer panel web 30 being wound, from which the outer panel part 100 of the other of the double-layer panels 10 (second double-layer panel) of the bag 1 will be formed. The roll 31' is formed by a second inner panel web 31 being wound, from which the inner panel part 101 of the second double-layer panel 10 will be formed.

[0031] The outer panel webs 20 and 30 each have a laminated structure, for example. Each of the outer panel webs 20 and 30 includes a first surface layer, such as a base layer, and a second surface layer, such as a sealant layer, having a lower melting point than that of the first surface layer. The inner panel webs 21 and 31 only have to be made of material having a lower melting point than that of the base layer (first surface layer) of the outer panel webs 20 and 30. Other characteristics (e.g., thickness) of these webs 20 to 31 are determined according to the characteristics (e.g., bag strength) of the bags 1 to be made. This is the same as in Patent Document 1.

[0032] The bag making apparatus includes a pair of superposing rollers 50 for superposing the webs 20 to 31 on each other. Each of the webs 20 to 31 is unwound from its roll 20' to 30', fed at a constant speed in its longitudinal direction through a well-known accumulator and a well-known dancer roller (not shown), and then guided to the pair of superposing rollers 50. Here, the dancer rollers are provided for the respective webs 20 to 31 to appropriately switch the webs 20 to 31 from continuous feed to intermittent feed. That is, the webs 20 to 31 are intermittently fed through the pair of superposing rollers 50. For this purpose, the bag making apparatus further includes an intermittent feeder 53 (see Figs. 5A and 5B) located in the downstream section of the apparatus to intermittently feed the webs 20 to 31 in their longitudinal direction. Thus, the webs 20 to 31 repeat to be fed and paused.

[0033] As illustrated in Fig. 2A, the webs 20 to 31 are guided to the pair of superposing rollers 50 to be superposed on each other at the pair of superposing rollers 50. The order thereof is, from top to bottom, is the outer panel web 20, the inner panel web 21, the inner panel web 31, and the outer panel web 30. Here, the higher-melting-point first surface layer (base layer) of the outer panel web 20 is oriented in the upward direction Z1, while the lower-melting-point second surface layer (sealant layer) is oriented in the downward direction Z2 and adjoins the inner panel web 21. The higher-melting-point first surface layer of the outer panel web 30 is oriented in the downward direction Z2, while the lower-melting-point second surface layer is oriented in the upward direction Z1 and adjoins the inner panel web 31.

[0034] To superpose the webs 20 to 31 in the above-described order and orientation, it has been appropriately selected whether the rolls 20' and 30' are formed by the webs 20 and 30 being wound with their first surface layer oriented inward or outward. Furthermore, an appropriate number of guides, such as inclined plates, which involve the conversion of the orientation of the webs 20 and 30, have been installed in the appropriate locations.

[0035] Furthermore, the bag making apparatus includes web formers 6 (Fig. 7A), which will be described in detail later. The web formers 6 in this embodiment are gusset formers each of which supplies a double-layer gusset web 4 (an example of a double-layer web folded in half) (Fig. 2A, Fig. 2B) to a space between two inner panel webs 21 and 31 in the area upstream of the pair of superposing rollers 50 to interpose the double-layer gusset web 4 between the inner panel webs 21 and 31 in the longitudinal direction of the webs 20 to 31 when the webs 20 and 31 are superposed on each other at the pair of superposing rollers 50. Hereinafter, each of the web formers 6 is referred to as "gusset former".

[0036] As indicated by the two arrows R1 and R2 in Fig. 2B, two double-layer gusset webs 4 are supplied from the opposite sides of the webs 20 to 31 in the width direction of the webs 20 to 31, redirected to the direction X1, and extend along the opposite sides of the webs 20 to 31. Therefore, the double-layer gusset webs 4 are intermittently fed by the intermittent feeder 53 together with the webs 20 to 31 in the longitudinal direction thereof (i.e. in the direction X1) in the area downstream of the pair of superposing rollers 50.

[0037] The double-layer gussets 11 of the bags 1 will be formed from these gusset webs 4. Each of the double-layer gusset webs 4 consists of an outer gusset web 40 and an inner gusset web 41, which have been folded in half after being superposed on each other, as illustrated in Fig. 6B. The outer gusset parts 111 of the double-layer gussets 11 will be formed from the outer gusset web 40. The outer gusset web 40, similar to the outer panel webs 20 and 30, has, for example, a laminated structure and thus incudes a first surface layer (base layer) and a second surface layer (sealant layer) having a lower melting point than that of the first surface layer. The inner gusset parts of the double-layer gussets 11 will be formed from the inner gusset web 41. The inner gusset web 41, similar to the inner panel webs 21 and 31, is made of material having a lower melting point than those of the first surface layers (base layers) of the outer panel webs 20 and 30 and the outer gusset web 40. As illustrated in in Figs. 2B and 6B, each of the double-layer gusset webs 4 is supplied such that its open edges 44 align with one side edges of the webs 20 to 31 and its folded edge 43 is positioned inward.

[0038] Figs. 3A and 3B illustrate the midstream section of the example bag making apparatus. The first double-layer panels 10 of the bags 1 will be formed from the webs 20 and 21. Therefore, the superposed webs 20 and 21 may be referred to as the (first) double-layer panel web 2 below. Similarly, since the second double-layer panels 10 of the bags 1 will be formed from the superposed webs 30 and 31, the superposed webs 30 and 31 may be referred to as the (second) double-layer panel web 3.

[0039] The bag making apparatus further includes a spout attacher 51 disposed downstream of the pair of superposing rollers 50 to attach the spout 12 to the first double-layer panel web 2 during every intermittent feed cycle.

[0040] The spout attacher 51 includes multiple guide rollers 510 for separating the second double-layer panel web 3 and the double-layer gusset web 4 from the first double-layer panel web 2 to create a temporary separation zone where the webs 2 to 4 are temporarily separated. In this example as illustrated in Fig. 3B, the web 2 to which the spout 12 is to be attached is fed horizontally, while the webs 3 and 4 are temporarily separated in the downward direction Z2. The temporary separation zone ensures that the webs 3 and 4 do not interfere with attaching the spouts 12 to the web 2.

[0041] The spout attacher 51 further includes a temporary fixing unit 511, a punching unit 512, and an attaching unit 513, which are located in this separation zone.

[0042] Figs. 4A and 4B illustrate the region T in Fig. 3A. The temporary fixing unit 511 temporarily fixes the webs 20 and 21 to each other by heat-sealing them in point like manner during every pause phase in the intermittent feed, to form a point sealed section 16. This prevents the webs 20 and 21 from being displaced relative to each other until the spout 12 is attached to the webs 20 and 21 as illustrated in Fig. 4C.

[0043] The point sealed section 16 is preferably located near the attachment position SA where the spout 12 is to be attached. As illustrated in Fig. 4A, for example, the point sealed section 16 is preferably located near this position SA and included within the area CS where the later-described cross seal is to be applied. Furthermore, as illustrated in Fig. 4B, the annular point sealed section 16 may be formed along the periphery of the position SA. The position of the point sealed section 16 in Fig. 4B is the position that will be sealed by the attaching unit 513, which will be described later.

[0044] The webs 2 to 4 are slit along the opposite side edges thereof, and the wastes generated by the slitting are removed, as described below. The point sealed section 16 may be formed in the portion to be removed as this waste. Unlike the examples illustrated in Figs. 4A and 4B, two or more point sealed sections may be provided for a single position SA.

[0045] The punching unit 512 is disposed downstream of the temporary sealing unit 511 by one intermittent feed pitch. The punching unit 512 punches a hole 17 (Fig. 4C) for the spout 12 in the web 2 (i.e., the webs 20 and 21 which have been temporarily sealed via the point sealed section 16) at the position SA during every pause phase in the intermittent feed. The punching unit 512 may punch the hole 17 in the web 2 using a punch blade. The wastes generated by punching the holes 17 are suctioned away by a suction unit (not shown).

[0046] The attaching unit 513 is disposed downstream of the punching unit 512 by at least one intermittent feed pitch to attach the spout 12 to the web 2 during every pause phase in the intermittent feed. As illustrated in Fig. 4C, a spout 12 with a flange 120 is used. The attaching unit 513 includes a heat seal block (not shown) having an annular shape corresponding to the shape of the flange 120. The attaching unit 513 inserts the spout 12 into the hole 17 from below and contacts the heat seal block onto the web 20 from above, thereby heat-sealing the flange 120 to the web 21. At this time, the webs 20 and 21 are also heat-sealed to each other, since the low-melting-point second surface layer of the web 20 is in contact with the web 21. Consequently, the spout 12, the web 20, and the web 21 are integrally welded.

[0047] The spout attacher 51 further includes a spout detection unit 514 disposed downstream of the attaching unit 513 in the temporary separation zone. The spout detection unit 514 determines whether a spout 12 has been properly attached to the web 2, using a sensor (e.g., an optical sensor) (not shown). The spout detection unit 514 outputs a warning when determining that the spout 12 has not been properly attached.

[0048] These units 511 to 514 have well-known structures, so their detailed description is omitted here.

[0049] Subsequently, the webs 2 to 4 are superposed on each other again by the downstream guide rollers 510. The bag making apparatus includes a temporary fixer 52 disposed downstream of the spout attacher 51. The temporary fixer 52 temporarily fixes these webs 2 to 4 to each other by means of heat-sealing, thereby preventing them from being misaligned in the downstream zone. The position of this temporary fixing may be within the area (e.g., the area CS in Fig .4A) where heat seal is to be subsequently applied.

[0050] Figs. 5A and 5B schematically illustrate the downstream section of the exemplary bag making apparatus. The bag making apparatus includes an intermittent feeder 53 configured to intermittently feed the webs 2 to 4 in their longitudinal direction. The intermittent feeder 53 includes at least one pair of drive rollers 530. The pair of drive rollers 530 intermittently rotates via a servo motor while nipping the webs 2 to 4, thereby intermittently feeding the webs 2to 4 in their longitudinal direction (in the direction X1). For example, multiple pairs of drive rollers 530 are arranged in position.

[0051] The bag making apparatus further includes at least one heat sealer 54 and 56 disposed downstream of the temporary fixer 52 to heat-seal the webs 2 to 4 during every intermittent feed cycle. In this example, a longitudinal sealer 54 and a cross sealer 56 are provided.

[0052] The longitudinal sealer 54 heat-seals the webs 2 to 4 in their longitudinal direction during every pause phase in the intermittent feed to form first sealed sections 13 (see Fig. 1A, Fig. 6A) along the opposite side edges of the webs 2 to 4. As described above, the webs 21, 31, and 41 are made of low-melting-point material. Therefore, as is clear from the relative positions of the respective webs 2 to 4 in Fig. 6B, the four layers of the webs 20, 21, 40, and 41 are integrally welded, and the four layers of the webs 30, 31, 40, and 41 are integrally welded. On the other hand, the two facing surfaces of the folded outer gusset web 40 are the high-melting-point first surface layers and thus are not welded to each other. This is also true for the subsequent cross seal.

[0053] The longitudinal sealer 54 may sandwich them between heat seal bars to heat-seal them. Here, it is preferable to use heat seal bars longer than twice the longitudinal dimension H (Fig. 6A) of the bag 1 (corresponding to the intermittent feed pitch). This enables the longitudinal sealer 54 to heat-seal the same section at least twice.

[0054] The cross sealer 56 heat-seals the webs 2 to 4 in their width direction during every pause phase in the intermittent feed to form the second sealed sections 14 (see Fig. 1A, Fig. 6A) which extend over the entire width of the webs 2 to 4. At this time, the inner panel webs 21 and 31 are welded to each other in the area where the web 4 is absent.

[0055] This example cross sealer 56 also forms the third sealed sections 15 (see Fig. 1A, Fig. 6A). For this purpose, the cross sealer 56 may use substantially K-shaped heat seal bars 560, as illustrated in Fig. 6C. Alternatively, the cross sealer 56 may use a straight heat seal bar 561 for forming the second sealed section 14 and a bifurcated heat seal bar 562 for forming the third sealed sections 15, as illustrated in Fig. 6D.

[0056] The root portion of the heat seal bar 560 or the bifurcation of the heat seal bar 562 is used for heat-sealing the central section of the webs 2 and 3, i.e., the section where the web 4 is absent. This area has fewer layers of webs compared to the surrounding area, resulting in a step. This step can cause sealing defect. Additional point seal may be applied to this section to prevent such sealing defect.

[0057] The bag making apparatus further includes a longitudinal cooler 55 disposed downstream of the longitudinal sealer 54, and a cross cooler 57 disposed downstream of the cross sealer 56. During every intermittent feed cycle, the longitudinal cooler 55 cools the first sealed sections 13, and the cross cooler 57 cools the second and third sealed sections 14 and 15. This cooling step smooths the sealed surface, providing a high-quality finished sealed surface.

[0058] The bag making apparatus further includes a slit device 58 disposed downstream of the heat sealers 54 and 56 and the cooler 55 and 57 to slit the webs 2 to 4 along the opposite side edges of the webs 2 and 3. The slit device 58 includes slitters positioned on the opposite sides of the webs 2 and 3. Therefore, as the webs 2 to 4 are fed, they are slit by the slitters along the opposite side edges of the web 2 and 3. The wastes generated during this process are wound to be collected by well-known means. The new edges of the webs 2 to 4 resulting from the slitting exhibit high straightness. Consequently, the opposite side edges (the edges of the first sealed sections 13) of the shaped bag 1 also exhibit high straightness.

[0059] The bag making apparatus further includes a cross cutter 59 disposed downstream of the slit device 58 to cross-cut the webs 2 to 4 in their width direction during every intermittent feed cycle, to shape a double-layer bag 1. Specifically, the cross cutter 59 cross-cuts the webs 2 to 4 in their width direction using a blade during every intermittent feed cycle, to obtain the portion cut out from the webs 2 to 4 as the double-layer bag 1 illustrated in Fig. 1A and Fig. 6A. This cross-cutting position is located within the second sealed section 14 of the webs 2 to 4, more specifically, the centerline of the cross seal area CS, as indicated by the reference numeral CR in Figs. 4A and 4B.

[0060] The bag 1 completed by the cross-cutting is conveyed by a conveyor (not shown).

[0061] With reference to Figs. 7A to 9E, a configuration of a gusset former 6 (an example of a web former) for forming and supplying a double-layer gusset web 4 (an example of a double-layer web folded in half) will be described. The exemplary bag making apparatus includes two gusset formers 6. One gusset former 6 supplies the web 4 from one side of the webs 20 to 31, as indicated by the arrow R1 in Fig. 2B. The other gusset former (not shown) supplies the web 4 from the other side of the webs 20 to 31, as indicated by the arrow R2. The configurations of both gusset formers are symmetrical with respect to the direction X1. Therefore, the former gusset former 6 is described, and the description of the latter gusset former is omitted.

[0062] In the gusset former 6 illustrated in Figs. 7A and 7B, two rolls 40' and 41' are installed. The roll 40' is formed by an outer gusset web 40 (an example of a first web) being wound, from which the outer gusset parts 110 of the double-layer gussets 11 of the bags 1 will be formed. The roll 41' is formed by an inner gusset web 41 (an example of a second web) being wound, form which the inner gusset parts 111 will be formed.

[0063] The material and composition of the outer gusset web 40 and the inner gusset web 41 are described above. In this example, the roll 40' is formed by the laminate structure web 40 being wound with its higher-melting-point first surface layer oriented outward and with its lower-melting-point second surface layer oriented inward.

[0064] The gusset former 6 includes inclined plates 60 and 61 provided for the respective webs 40 and 41. Fig. 9A is a sectional view as viewed from the arrow S1 in Fig. 7A, and Fig. 9B is a sectional view as viewed from the arrow S2 in Fig. 7A. The webs 40 and 41 are continuously unwound from their rolls 40' and 41', fed at a constant speed in their longitudinal direction to the inclined plates 60 and 61, and redirected from the upward direction Z1 to the horizontal direction Y1 by the inclined plates 60 and 61, respectively. The horizontal direction Y1 is perpendicular to the feed direction X1 of the webs 20 to 31 used for the double-layer panels 10. For this purpose, the bag making apparatus (gusset former 6) includes first and second continuous feeders 690 and 691 (illustrated only in Fig. 8). The first / second continuous feeder 690 / 691 is provided for the web 40 / 41, located downstream of the inclined plate 60 / 61 and upstream of the first / second stationary rollers 621 / 631 to continuously feed the web 40 / 41 in its longitudinal direction. For example, the first and second continuous feeders 690 and 691 each include a pair of drive rollers.

[0065] The gusset former 6 further includes a first tension adjuster 62 for the outer gusset web 40, disposed downstream of the inclined plate 60, and a second tension adjuster 63 for the inner gusset web 41, disposed downstream of the inclined plate 61. The webs 40 and 41 are redirected to the horizontal direction Y1 by the inclined plates 60 and 61, and then fed through the first and second tension adjusters 62 and 63, respectively.

[0066] The first tension adjuster 62 switches the web 40 from the continuous feed to the intermittent feed and appropriately controls the tension of the web 40, so that the web 40 is intermittently fed without slack or meandering. The second tension adjuster 63 switches the web 41 from the continuous feed to the intermittent feed and appropriately controls the tension of the web 41, so that the web 41 is intermittently fed without slack or meandering. The tension control of the web 40 using the first tension adjuster 62 and the tension control of the web 41 using the second tension adjuster 63 are independent of each other.

[0067] The first tension adjuster 62 in the embodiment is a first dancer mechanism which includes a first dancer roller 620 for engaging with the web 40 to apply tension to the web 40, and two first stationary rollers 621 disposed upstream and downstream of the first dancer roller 620 in a stationary manner to guide the web 40 for engaging the web 40 with the first dancer roller 620.

[0068] As illustrated only in Fig. 8, which is a detailed view of the region Q in Fig. 7, the first tension adjuster 62 further includes a first actuator 622 for supporting the first dancer roller 620 for linear shift (in the left-and-right direction in Fig. 8) of this roller and for biasing the first dancer roller 620 towards the web 40, a first sensor 623 for detecting the position of the first dancer roller 620, and a first controller 624 (including one or more processors) for controlling the first continuous feeder 690.

[0069] The first dancer roller 620 shifts left or right in Fig. 8 as the web 40 is intermittently fed by the intermittent feeder 53. During this shift, the first sensor 623 is detecting the position of the first dancer roller 620. Then, the first controller 624 changes the feed speed of the web 40 (the rotational speed of its pair of drive rollers) via the first continuous feeder 690 based on the measurements from the first sensor 623. Through this series of controls, the first controller 624 maintains the shift of the first dancer roller 620 within the predetermined range, thereby adjusting the tension of the web 40 while appropriately switching the web 40 from the continuous feed to the intermittent feed.

[0070] The second tension adjuster 63 in the embodiment is a second dancer mechanism having a configuration similar to that of the first dancer mechanism, and thus includes a second dancer roller 630, second stationary rollers 631, a second actuator 632, a second sensor 633, and a second controller 634 (including one or more processors), as illustrated in Fig. 8.

[0071] The second sensor 633 is detecting the position of the second dancer roller 630 which is shifting as the web 41 is intermittently fed by the intermittent feeder 53. The second controller 634 then changes the feed speed of the web 41 (e.g., the rotational speed of the continuous feed roller pair) via the second continuous feeder 691 based on the measurements from the second sensor 633, thereby adjusting the tension of the web 41 while appropriately switching the web 41 from the continuous feed to the intermittent feed.

[0072] The first and second tension adjusters 62 and 63 are not limited to the dancer mechanisms; other configurations than the dancer mechanisms may be adopted. Alternative to the above embodiment, the first and second controllers 624 and 634 may be constituted by a single controller, which controls the tension of the web 40 and the tension of the web 41 independently of each other.

[0073] The webs 40 and 41 are intermittently fed by the intermittent feeder 53 as described above. In addition to this feeder, the gusset former 6 may also include an additional intermittent feeder (not shown) which includes an appropriate number of pair of drive rollers and servo motors having the similar configurations to those of the intermittent feeder 53 of the bag making apparatus. The feed pitch of this intermittent feed, which is indicated by the reference numeral P in Fig. 7A, is set equal to that of the intermittent feed of the webs 20 to 31 and thus corresponds to the longitudinal dimension H (Fig. 6A) of bag 1. Furthermore, the timings of both intermittent feeds are also set to be mutually equal.

[0074] The gusset former 6 further includes a guide 64 disposed downstream of the tension adjusters 62 and 63, a single triangular plate 65 disposed downstream of and adjacent to the guide 64, a pair of crease rollers 66 disposed downstream of the triangular plate 65, a temporary fixer 67 for the webs 40 and 41, disposed downstream of the pair of crease rollers 66, and a puncher 68 disposed downstream of the temporary fixer 67. The guide 64 in the embodiment is a guide roller. These components 64 to 68 are arranged in the space created by and between the two inner panel webs 21 and 31 before being superposed, upstream of the pair of superposing rollers 50 (e.g., Fig. 2A).

[0075] The webs 40 and 41, after being fed through the tension adjusters 62 and 63, respectively, are fed sequentially through the guide 64 and the triangular plate 65. As the webs 40 and 41 are fed, they are first superposed on each other by the guide 64 at the guide 64, and then guided to the triangular plate 65 in the superposed state. At this time, the lower-melting-point second surface layer of the outer gusset web 40 contacts the inner gusset web 41.

[0076] Fig. 9C is a sectional view as viewed from the arrow F in Fig. 7A, and Fig. 9D is an enlarged sectional view as viewed from the arrow J in Fig. 9C. As illustrated in Figs. 7A, 9C, and 9D, the webs 40 and 41, which have been superposed on each other by the guide 64, are guided by the triangular plate 65 to be folded in half along the fold line 42 (Fig. 9C) extending in their longitudinal direction as they are fed, so that the folded outer gusset web 40 is interposed between the folded inner gusset web 41 as illustrated in Fig. 7A. The webs 40 and 41 are then fed through the pair of crease rollers 66, the pair of crease rollers 66 completes the folding and emphasizes the crease during this feed. Passing the webs 40 and 41 through the guide 64 and the triangular plate 65 causes the webs 40 and 41 to be redirected from the direction Y1 to the direction X1.

[0077] The double-layer gusset web 4 has been formed in this way. The fold line 42 coincides with the widthwise centerline of the webs 40 and 41. The reference numeral 43 in Figs. 7A and 9D designates the folded edge 43 of the double-layer gusset web 4, which is formed on the fold line 42. The reference numeral 44 designates the open edges of the double-layer gusset web 4. The two facing surfaces of the folded web 40 are the high-melting-point first surface layer.

[0078] The gusset temporary fixer 67 temporarily fixes the webs 40 and 41 by means of heat-sealing or ultrasonic-sealing during every intermittent feed cycle, to form the point sealed section 18 (see Fig. 9E, which is an enlarged view of the area G in Fig. 7A). This prevents misalignment of the webs 40 and 41. The position of the point sealed section 18 is, for example, within the cross seal area CS described above.

[0079] The puncher 68 punches holes 19 (Fig. 9E) for heat-sealing in the double-layer gusset web 4 during every intermittent feed cycle. The positions of the holes 19 are within the cross seal area CS. Furthermore, the holes 19 are formed on both sides with respect to the cross cut position CR described above, for example.

[0080] For example, the puncher 68 may use punch blades to punch the holes 19 in the web 4. The puncher 68 includes a suction unit (not shown) to suction the wastes generated by punching the holes 19, as in the well-known puncher. The puncher 68 also includes a waste detection unit (not shown) which detects whether a waste is adhered to the web 4 without being suctioned using a sensor and outputs a warning when detecting a waste adhered to the web 4.

[0081] As described above, the double-layer gusset web 4 is then interposed between the inner panel webs 21 and 31 when the webs 20 to 31 for the double-layer panels 10 are superposed on each other at the pair of superposing rollers 50. Also, as described above, at this time, the open edges 44 align with one side edges of the webs 20 to 31 and the folded edge 43 is positioned inward as illustrated in Fig. 2B.

[0082] In this example, when the cross sealer 56 heat-seals the webs 2 to 4 in their width direction thereof, the point sealed section 18 is completely contained within and integrated into the second sealed section 14 to disappear, and the inner panel webs 21 and 31 are welded to each other through the holes 19.

[0083] In general, folding both the inner gusset web and the outer gusset web with a single triangular plate, as in Patent Document 1, may cause one of them to sag or meander, which may result in poor finish of the double-layer gusset web.

[0084] To address this problem, the gusset former 7 in Fig. 10A according to the related art includes triangular plates 70 and 71 provided for the respective webs 40 and 41, and a disc-shaped rotatable guide plate 72 disposed downstream of the triangular plates 70 and 71. The gusset former 7 then folds the web 40 in half using the triangular plate 70 and the web 41 in half using the triangular plate 71, and then aligns the folded edges of both webs 40 and 41 using the guide plate 72 with each other. However, the combination of the two triangular plates 70 and 71 and the disc-shaped guide plate 72 may cause a gap 45 to be formed between the web 40 and the web 41, as illustrated in Fig. 10B, which thus may adversely affect the finished quality of the double-layer bags 1.

[0085] The gusset former 6 according to the present application folds the superposed webs 40 and 41 using the single triangular plate 65 as described above, however, in its upstream zone, the first and second tension adjusters 62 and 63 control the tension of the web 40 and the tension of the web 41 independently of each other, respectively. Therefore, the problem of the prior art that the webs 40 and 41 sag or meander during the formation of the double-layer gusset web 4 does not occur. Furthermore, folding the superposed webs 40 and 41 in half together simultaneously prevents the gap 45 described in the related art from occurring.

[0086] Therefore, the gusset former 6 according to the present application can form the double-layer gusset web 4 with a higher quality finish than the prior art or related art. Consequently, the bag making apparatus in the present application with this gusset former 6 can provide double-layer bags 1 with higher quality.

[0087] Similar to Patent Document 2, the above double-layer bag 1 may be used, for example, as an inner bag for a bag-in-box.

[0088] Alternative to the laminated structure, each of the webs 20, 30 and 40 may consist of a film made of mono-material and medium ink partially or fully applied to the film to inhibit heat seal. Each of the webs 20 to 41 may include paper as a base and resin partially or fully coated onto the paper. It would be appreciated by those skilled in the art that, as long as the double-layer bags 1 can be made, the webs 20 to 41 are not limited to the example configurations and materials described above.

[0089] Alternatively, the webs 20 and 30 may be formed by slitting a wide web unwound from a single roll. The webs 21 and 31 may also be formed by slitting a wide web unwound from a single roll.

[0090] The primary role of the pair of superposing rollers 50 is to converge the feed lines for the webs 2, 3, and 4, not to feed the webs 2, 3, and 4. Therefore, the pair of superposing rollers 50 does not have to nip the webs 2, 3, and 4, and its force for nipping may be very weak or even zero. Conversely, it should be taken care that excessive force for nipping may cause misalignment of the laminated body of the webs 2, 3 and 4 among them.

[0091] In the above embodiments, the double-layer web formed by the web former 6 is used as a double-layer gusset web. In other embodiments, the double-layer web formed by the web former 6 having the same structure as above is used as a double-layer panel web folded in half.

[0092] In one of these alternative embodiments, the folded double-layer panel web is formed by the web former 6, and then subject to at least a heat-sealing process and a cross-cutting process by a bag making apparatus, so that the double-layer bags without any gussets are made. This double-layer bag includes a folded outer panel and a folded inner panel interposed between the folded outer panel, wherein the outer panel is formed from the second web 41 of the double-layer panel web and the inner panel is formed from the first web 40 of the double-layer panel web. In order to implement the heat-sealing process, the alternative embodiment uses material with a higher melting point for the outer layer of the second web 41, material with a lower melting point for the inner layer of the second web 41, and material with a lower melting point for the first web 40.

[0093] The bag making apparatus according to the present application may make double-layer bags each having a zipper as an alternative to or in addition to the spout 12. The bag making apparatus according to the present application may also make double-layer bags each with a double-layer gusset functioning as a top gusset or a bottom gusset instead of the double-layer gussets 11 functioning as the side gussets as illustrated above. That is, bag making using the double-layer gusset web(s) 4 as a top gusset and / or bottom gusset may be implemented.EXPLANATIONS OF LETTERS OR NUMERALS

[0094] 1 double-layer bag 10 double-layer panel 11 double-layer gusset 12 spout 17 hole for spout 19 hole for heat-sealing 2 first double-layer panel web 20 first outer panel web 21 first inner panel web 3 second double-layer panel web 30 second outer panel web 31 second inner panel web 4 double-layer gusset web (an example of double-layer web folded in half) 40 outer gusset web (an example of first web) 41 inner gusset web (an example of second web) 42 fold line 50 pair of superposing rollers 51 spout attacher 510 guide roller 511 temporary fixing unit 512 punching unit 513 attaching unit 53 intermittent feeder 54 longitudinal sealer (an example of heat sealer) 56 cross sealer (an example of heat sealer) 59 cross cutter 6 web former (gusset former) 62 first tension adjuster (first dancer mechanism) 620 first dancer roller 63 second tension adjuster (second dancer mechanism) 630 second dancer roller 64 guide (guide roller) 65 triangular plate 67 temporary fixer

Examples

Embodiment Construction

[0021]The embodiments of the present application will now be described with reference to the drawings. The following embodiments are merely examples of the present inventions.

[0022]Fig. 1A illustrates an example double-layer bag 1. The double-layer bag 1 includes two double-layer panels 10 facing each other. As illustrated in Fig. 1B, which is a sectional view, each of the double-layer panels 10 consists of an outer panel part 100 and an inner panel part 101 superposed on each other. A storage space is formed by and between these two double-layer panels 10. The two inner panel parts 101 face each other and are interposed between the two outer panel parts 100.

[0023]The double-layer bag 1 further includes two double-layer gussets 11. The two double-layer gussets 11 form a pair, are folded to be interposed between the two double-layer panels 10, and extend along the opposite side edges of the double-layer panels 10. That is, the example double-layer gussets 11 function as side gussets ...

TECHNICAL FIELD

[0001] The present application relates to a web former and a method for forming a double-layer web folded in half, such as a double-layer gusset web, for use in making double-layer bags. The present application also relates to a bag making apparatus for successively making double-layer bags.BACKGROUND

[0002] Double-layer bags are well-known, for example, as disclosed in Patent Documents 1 and 2. A double-layer bag at least includes two double-layer panels facing each other. A storage space is formed by and between these two double-layer panels. Each of the double-layer panels consists of an inner panel part and an outer panel part which are superposed on each other.

[0003] The double-layer bags disclosed in Patent Documents 1 and 2 each further include a pair of double-layer gussets. Each of the double-layer gussets also has a double-layer structure and thus consists of an outer gusset part and an inner gusset part which have been folded in half with themselves superposed on each other.

[0004] Patent Document 1 discloses a bag making apparatus for successively making such double-layer bags. The bag making apparatus includes a gusset former that forms a double-layer gusset web from which the double-layer gussets will be formed. The gusset former unwinds an outer gusset web (for the outer gusset parts) and an inner gusset web (for the inner gusset parts) from their respective rolls, and superposes them on each other. The gusset former then folds the superposed outer gusset web and inner gusset web in half along a fold line extending in their longitudinal direction, thereby forming the double-layer gusset web.

[0005] Patent Document 1 discloses folding the superposed outer gusset web and inner gusset web in half with only one triangular plate. This configuration, which folds two webs with a single triangular plate, typically may cause one of the two webs to sag or meander. It is therefore difficult to fold the outer gusset web and the inner gusset web with a neat alignment. If the double-layer gusset web is poorly finished, the finished bag, of course, will have poor quality.CITATION LIST PATENT DOCUMENT

[0006] Patent Document 1: JPA 2016-141427 Patent Document 2: JPA 2022-7011SUMMARY

[0007] The present application provides a web former and a web forming method for forming a well-finished double-layer web folded in half, and a bag making apparatus including said web former.

[0008] According to the present application, there is provided a web former for use in making double-layer bags and for forming a double-layer web folded in half and including a first web and a second web, the web former including: a first tension adjuster configured to control tension of the first web being fed in a longitudinal direction of the first web; a second tension adjuster configured to control tension of the second web being fed in a longitudinal direction of the second web independently of the first tension adjuster; a guide disposed downstream of the first and second tension adjusters to guide the first web and the second web downstream while superposing the first web and the second web on each other; and a single triangular plate disposed downstream of the guide to fold the first and second webs superposed by the guide, in half along a fold line extending in the longitudinal direction of the first and second webs.

[0009] For example, the web former may be a gusset former for forming a double-layer gusset web as the double-layer web, the double-layer gusset web comprising an outer gusset web as the first web and an inner gusset web as the second web.

[0010] The first tension adjuster may further be configured to switch the first web from continuous feed to intermittent feed. The second tension adjuster may further be configured to switch the second web from continuous feed to intermittent feed.

[0011] The first tension adjuster may be a first dancer mechanism. The second tension adjuster may be a second dancer mechanism. The first dancer mechanism may include a first dancer roller for engaging with the first web to apply tension to the first web. The second dancer mechanism may include a second dancer roller for engaging with the second web to apply tension to the second web.

[0012] For example, the guide may be a guide roller.

[0013] The web former may further include a temporary fixer disposed downstream of the triangular plate and configured to temporarily fix the first web and the second web to each other.

[0014] According to the present application, there is also provided a bag making apparatus for successively making double-layer bags each comprising a first double-layer panel, a second double-layer panel, and a double-layer gusset, the bag making apparatus comprising: an intermittent feeder configured to intermittently feed a first outer panel web, a first inner panel web, a second outer panel web, and a second inner panel web in a longitudinal direction thereof; a pair of superposing rollers for superposing the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel web on each other in this order; the web former as the above-described gusset former, the web former being configured to supply the double-layer gusset web to interpose the double-layer gusset web between the first inner panel web and the second inner panel web in the longitudinal direction when the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel are superposed on each other at the pair of superposing rollers; at least one heat sealer disposed downstream of the pair of superposing rollers and configured to heat-seal the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web during every intermittent feed cycle; and a cross cutter disposed downstream of the at least one heat sealer and configured to cross-cut the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web in a width direction thereof during every intermittent feed cycle to shape a double-layer bag wherein the first double-layer panel is formed from the first outer panel web and the first inner panel web, the second double-layer panel is formed from the second outer panel web and the second inner panel web, and the double-layer gusset is formed from the double-layer gusset web.

[0015] The bag making apparatus may further include a spout attacher disposed downstream of the pair of superposing rollers and upstream of the at least one heat sealer, and configured to attach a spout to the first outer panel web and the first inner panel web superposed on each other during every intermittent feed cycle. The spout attacher may include: a plurality of guide rollers for temporarily separating the second outer panel web, the second inner panel web, and the double-layer gusset web from the first outer panel web and the first inner panel web to create a temporary separation zone; a temporary fixing unit disposed in the temporary separation zone and configured to temporarily fix the first outer panel web and the first inner panel web to each other; a punching unit disposed downstream of the temporary fixing unit in the temporary separation zone and configured to punch a hole for the spout in the first outer panel web and the first inner panel web; and an attaching unit disposed downstream of the punching unit in the temporary separation zone and configured to insert the spout into the hole and attach the inserted spout to the first outer panel web and the first inner panel web by heat-sealing.

[0016] The web former may further include a puncher configured to punch a hole for heat-sealing in the double-layer gusset web, and the at least one heat sealer may be configured to heat-seal the first and second inner panel webs to each other through the hole for heat-sealing.

[0017] Furthermore, according to the present application, there is also provided a web forming method for forming a double-layer web folded in half and including a first web and a second web for making double-layer bags, the method including: feeding the first web in a longitudinal direction of the first web; feeding the second web in a longitudinal direction of the second web; controlling tension of the first web using a first tension adjuster; controlling tension of the second web using a second tension adjuster independently of the controlling the tension of the first web using the first tension adjuster; guiding the first web and the second web downstream while superposing the first and second webs on each other using a guide located downstream of the first and second tension adjusters, and folding the superposed first and second webs in half along a fold line extending in the longitudinal direction of the first and second webs using a single triangular plate located downstream of the guide, to interpose the folded first web between the folded second web.

[0018] The first web may include a first surface layer and a second surface layer having a lower melting point than a melting point of the first surface layer, and the second web may have a lower melting point than the melting point of the first surface layer. The first web and the second web may be folded in half along the fold line by the triangular plate to contact the second surface layer with the second web.

[0019] The first web may be unwound from a first roll and continuously fed in the longitudinal direction thereof. The second web may be unwound from a second roll and continuously fed in the longitudinal direction thereof. The first web may be switched from continuous feed to intermittent feed by the first tension adjuster. The second web may be switched from continuous feed to intermittent feed by the second tension adjuster.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [Fig. 1] Fig. 1A illustrates an example double-layer bag, and Fig. 1B is a partial sectional view of the bag in Fig. 1A. [Fig. 2] Fig. 2A is a schematic side view of an upstream section of an example bag making apparatus, and Fig. 2B is a partial plan view of Fig. 2A. [Fig. 3] Fig. 3A is a schematic plan view of a midstream section of the example bag making apparatus, and Fig. 3B is a side view of Fig. 3A. [Fig. 4] Figs. 4A and 4B each illustrate an example point sealed section, and Fig. 4C illustrates an example of attaching a spout. [Fig. 5] Fig. 5A is a schematic plan view of a downstream section of the example bag making apparatus, and Fig. 5B is a side view of Fig. 5A. [Fig. 6] Fig. 6A illustrates an example double-layer bag, Fig. 6B is a partial sectional view of webs superposed on each other, and Figs. 6C and 6D illustrate example heat seal bars. [Fig. 7] Fig. 7A is a schematic plan view of an example gusset former, and Fig. 7B is a partial side view of Fig. 7A. [Fig. 8] Fig. 8 is a detailed view of a region Q in Fig. 7. [Fig. 9] Fig. 9A is a view as viewed from an arrow S1 in Fig. 7B, Fig. 9B is a view as viewed from an arrow S2 in Fig. 7B, Fig. 9C is a view as viewed from an arrow F in Fig. 7A, Fig. 9D is an enlarged view as viewed from an arrow J in 9C, and Fig. 9E is an enlarged view of a region G in Fig. 7A. [Fig. 10] Fig. 10A is a schematic plan view of a gusset former according to the related art, and Fig.10B is a sectional view of a gusset web formed by the gusset former in Fig. 10A according to the related art. DETAILED DESCRIPTION

[0021] The embodiments of the present application will now be described with reference to the drawings. The following embodiments are merely examples of the present inventions.

[0022] Fig. 1A illustrates an example double-layer bag 1. The double-layer bag 1 includes two double-layer panels 10 facing each other. As illustrated in Fig. 1B, which is a sectional view, each of the double-layer panels 10 consists of an outer panel part 100 and an inner panel part 101 superposed on each other. A storage space is formed by and between these two double-layer panels 10. The two inner panel parts 101 face each other and are interposed between the two outer panel parts 100.

[0023] The double-layer bag 1 further includes two double-layer gussets 11. The two double-layer gussets 11 form a pair, are folded to be interposed between the two double-layer panels 10, and extend along the opposite side edges of the double-layer panels 10. That is, the example double-layer gussets 11 function as side gussets to expand the storage space of the bag 1.

[0024] As illustrated in Fig. 1B, each of the double-layer gussets 11 consists of an outer gusset part 110 and an inner gusset part 111 superposed on each other. The outer gusset part 110 is located on the outside of the bag 1, whereas the inner gusset part 111 is located on the inside of the bag 1. When the double-layer gusset 11 is folded as illustrated in Fig. 1B, the folded outer gusset part 110 is interposed between the folded inner gusset part 111.

[0025] The double-layer bag 1 further includes a spout 12. The spout 12 is attached to one of the double-layer panels 10. Contents can be filled into or taken out of the storage space through the spout 12.

[0026] To ensure airtightness, the double-layer bag 1 includes first sealed sections 13 formed along the opposite side edges of the bag 1 and second sealed sections 14 formed along the top and bottom edges of the bag 1. In the first sealed sections 13 and the second sealed sections 14, each inner panel part 101 is welded to the adjacent outer panel part 100 and the adjacent inner gusset parts 111, and the outer gusset part 110 and the inner gusset part 111 are welded to each other. Furthermore, in the regions of the second sealed sections 14 where the double-layer gusset 11 is absent, the two inner panel parts 101 are welded to each other.

[0027] Similar to Patent Document 2, the double-layer bag 1 further includes third sealed sections 15 extending obliquely relative to the opposite side edges and the top and bottom edges of the bag 1. The third sealed sections 15 each extend obliquely from the end of the folded edge (inner edge) of the double-layer gusset 11 to the first sealed section 13. Also, in the respective third sealed sections 15, each inner panel part 101 is welded to the adjacent outer panel part 100 and the adjacent inner gusset part 111, and the outer gusset part 110 and the inner gusset part 111 are welded to each other.

[0028] It should be noted that the facing surfaces of the respective folded outer gusset parts 110 are not welded to each other.

[0029] An example bag making apparatus for successively making the above example double-layer bags 1 will now be described.

[0030] Fig. 2A schematically illustrates an upstream section of an example bag making apparatus. Four rolls 20', 21', 30' and 31' are installed. The roll 20' is formed by a first outer panel web 20 being wound, from which the outer panel part 100 of one of the two double-layer panels 10 (first double-layer panel) of the bag 1 will be formed. The roll 21' is formed by a first inner panel web 21 being wound, from which the inner panel part 101 of the first double-layer panel 10 will be formed. The roll 30' is formed by a second outer panel web 30 being wound, from which the outer panel part 100 of the other of the double-layer panels 10 (second double-layer panel) of the bag 1 will be formed. The roll 31' is formed by a second inner panel web 31 being wound, from which the inner panel part 101 of the second double-layer panel 10 will be formed.

[0031] The outer panel webs 20 and 30 each have a laminated structure, for example. Each of the outer panel webs 20 and 30 includes a first surface layer, such as a base layer, and a second surface layer, such as a sealant layer, having a lower melting point than that of the first surface layer. The inner panel webs 21 and 31 only have to be made of material having a lower melting point than that of the base layer (first surface layer) of the outer panel webs 20 and 30. Other characteristics (e.g., thickness) of these webs 20 to 31 are determined according to the characteristics (e.g., bag strength) of the bags 1 to be made. This is the same as in Patent Document 1.

[0032] The bag making apparatus includes a pair of superposing rollers 50 for superposing the webs 20 to 31 on each other. Each of the webs 20 to 31 is unwound from its roll 20' to 30', fed at a constant speed in its longitudinal direction through a well-known accumulator and a well-known dancer roller (not shown), and then guided to the pair of superposing rollers 50. Here, the dancer rollers are provided for the respective webs 20 to 31 to appropriately switch the webs 20 to 31 from continuous feed to intermittent feed. That is, the webs 20 to 31 are intermittently fed through the pair of superposing rollers 50. For this purpose, the bag making apparatus further includes an intermittent feeder 53 (see Figs. 5A and 5B) located in the downstream section of the apparatus to intermittently feed the webs 20 to 31 in their longitudinal direction. Thus, the webs 20 to 31 repeat to be fed and paused.

[0033] As illustrated in Fig. 2A, the webs 20 to 31 are guided to the pair of superposing rollers 50 to be superposed on each other at the pair of superposing rollers 50. The order thereof is, from top to bottom, is the outer panel web 20, the inner panel web 21, the inner panel web 31, and the outer panel web 30. Here, the higher-melting-point first surface layer (base layer) of the outer panel web 20 is oriented in the upward direction Z1, while the lower-melting-point second surface layer (sealant layer) is oriented in the downward direction Z2 and adjoins the inner panel web 21. The higher-melting-point first surface layer of the outer panel web 30 is oriented in the downward direction Z2, while the lower-melting-point second surface layer is oriented in the upward direction Z1 and adjoins the inner panel web 31.

[0034] To superpose the webs 20 to 31 in the above-described order and orientation, it has been appropriately selected whether the rolls 20' and 30' are formed by the webs 20 and 30 being wound with their first surface layer oriented inward or outward. Furthermore, an appropriate number of guides, such as inclined plates, which involve the conversion of the orientation of the webs 20 and 30, have been installed in the appropriate locations.

[0035] Furthermore, the bag making apparatus includes web formers 6 (Fig. 7A), which will be described in detail later. The web formers 6 in this embodiment are gusset formers each of which supplies a double-layer gusset web 4 (an example of a double-layer web folded in half) (Fig. 2A, Fig. 2B) to a space between two inner panel webs 21 and 31 in the area upstream of the pair of superposing rollers 50 to interpose the double-layer gusset web 4 between the inner panel webs 21 and 31 in the longitudinal direction of the webs 20 to 31 when the webs 20 and 31 are superposed on each other at the pair of superposing rollers 50. Hereinafter, each of the web formers 6 is referred to as "gusset former".

[0036] As indicated by the two arrows R1 and R2 in Fig. 2B, two double-layer gusset webs 4 are supplied from the opposite sides of the webs 20 to 31 in the width direction of the webs 20 to 31, redirected to the direction X1, and extend along the opposite sides of the webs 20 to 31. Therefore, the double-layer gusset webs 4 are intermittently fed by the intermittent feeder 53 together with the webs 20 to 31 in the longitudinal direction thereof (i.e. in the direction X1) in the area downstream of the pair of superposing rollers 50.

[0037] The double-layer gussets 11 of the bags 1 will be formed from these gusset webs 4. Each of the double-layer gusset webs 4 consists of an outer gusset web 40 and an inner gusset web 41, which have been folded in half after being superposed on each other, as illustrated in Fig. 6B. The outer gusset parts 111 of the double-layer gussets 11 will be formed from the outer gusset web 40. The outer gusset web 40, similar to the outer panel webs 20 and 30, has, for example, a laminated structure and thus incudes a first surface layer (base layer) and a second surface layer (sealant layer) having a lower melting point than that of the first surface layer. The inner gusset parts of the double-layer gussets 11 will be formed from the inner gusset web 41. The inner gusset web 41, similar to the inner panel webs 21 and 31, is made of material having a lower melting point than those of the first surface layers (base layers) of the outer panel webs 20 and 30 and the outer gusset web 40. As illustrated in in Figs. 2B and 6B, each of the double-layer gusset webs 4 is supplied such that its open edges 44 align with one side edges of the webs 20 to 31 and its folded edge 43 is positioned inward.

[0038] Figs. 3A and 3B illustrate the midstream section of the example bag making apparatus. The first double-layer panels 10 of the bags 1 will be formed from the webs 20 and 21. Therefore, the superposed webs 20 and 21 may be referred to as the (first) double-layer panel web 2 below. Similarly, since the second double-layer panels 10 of the bags 1 will be formed from the superposed webs 30 and 31, the superposed webs 30 and 31 may be referred to as the (second) double-layer panel web 3.

[0039] The bag making apparatus further includes a spout attacher 51 disposed downstream of the pair of superposing rollers 50 to attach the spout 12 to the first double-layer panel web 2 during every intermittent feed cycle.

[0040] The spout attacher 51 includes multiple guide rollers 510 for separating the second double-layer panel web 3 and the double-layer gusset web 4 from the first double-layer panel web 2 to create a temporary separation zone where the webs 2 to 4 are temporarily separated. In this example as illustrated in Fig. 3B, the web 2 to which the spout 12 is to be attached is fed horizontally, while the webs 3 and 4 are temporarily separated in the downward direction Z2. The temporary separation zone ensures that the webs 3 and 4 do not interfere with attaching the spouts 12 to the web 2.

[0041] The spout attacher 51 further includes a temporary fixing unit 511, a punching unit 512, and an attaching unit 513, which are located in this separation zone.

[0042] Figs. 4A and 4B illustrate the region T in Fig. 3A. The temporary fixing unit 511 temporarily fixes the webs 20 and 21 to each other by heat-sealing them in point like manner during every pause phase in the intermittent feed, to form a point sealed section 16. This prevents the webs 20 and 21 from being displaced relative to each other until the spout 12 is attached to the webs 20 and 21 as illustrated in Fig. 4C.

[0043] The point sealed section 16 is preferably located near the attachment position SA where the spout 12 is to be attached. As illustrated in Fig. 4A, for example, the point sealed section 16 is preferably located near this position SA and included within the area CS where the later-described cross seal is to be applied. Furthermore, as illustrated in Fig. 4B, the annular point sealed section 16 may be formed along the periphery of the position SA. The position of the point sealed section 16 in Fig. 4B is the position that will be sealed by the attaching unit 513, which will be described later.

[0044] The webs 2 to 4 are slit along the opposite side edges thereof, and the wastes generated by the slitting are removed, as described below. The point sealed section 16 may be formed in the portion to be removed as this waste. Unlike the examples illustrated in Figs. 4A and 4B, two or more point sealed sections may be provided for a single position SA.

[0045] The punching unit 512 is disposed downstream of the temporary sealing unit 511 by one intermittent feed pitch. The punching unit 512 punches a hole 17 (Fig. 4C) for the spout 12 in the web 2 (i.e., the webs 20 and 21 which have been temporarily sealed via the point sealed section 16) at the position SA during every pause phase in the intermittent feed. The punching unit 512 may punch the hole 17 in the web 2 using a punch blade. The wastes generated by punching the holes 17 are suctioned away by a suction unit (not shown).

[0046] The attaching unit 513 is disposed downstream of the punching unit 512 by at least one intermittent feed pitch to attach the spout 12 to the web 2 during every pause phase in the intermittent feed. As illustrated in Fig. 4C, a spout 12 with a flange 120 is used. The attaching unit 513 includes a heat seal block (not shown) having an annular shape corresponding to the shape of the flange 120. The attaching unit 513 inserts the spout 12 into the hole 17 from below and contacts the heat seal block onto the web 20 from above, thereby heat-sealing the flange 120 to the web 21. At this time, the webs 20 and 21 are also heat-sealed to each other, since the low-melting-point second surface layer of the web 20 is in contact with the web 21. Consequently, the spout 12, the web 20, and the web 21 are integrally welded.

[0047] The spout attacher 51 further includes a spout detection unit 514 disposed downstream of the attaching unit 513 in the temporary separation zone. The spout detection unit 514 determines whether a spout 12 has been properly attached to the web 2, using a sensor (e.g., an optical sensor) (not shown). The spout detection unit 514 outputs a warning when determining that the spout 12 has not been properly attached.

[0048] These units 511 to 514 have well-known structures, so their detailed description is omitted here.

[0049] Subsequently, the webs 2 to 4 are superposed on each other again by the downstream guide rollers 510. The bag making apparatus includes a temporary fixer 52 disposed downstream of the spout attacher 51. The temporary fixer 52 temporarily fixes these webs 2 to 4 to each other by means of heat-sealing, thereby preventing them from being misaligned in the downstream zone. The position of this temporary fixing may be within the area (e.g., the area CS in Fig .4A) where heat seal is to be subsequently applied.

[0050] Figs. 5A and 5B schematically illustrate the downstream section of the exemplary bag making apparatus. The bag making apparatus includes an intermittent feeder 53 configured to intermittently feed the webs 2 to 4 in their longitudinal direction. The intermittent feeder 53 includes at least one pair of drive rollers 530. The pair of drive rollers 530 intermittently rotates via a servo motor while nipping the webs 2 to 4, thereby intermittently feeding the webs 2to 4 in their longitudinal direction (in the direction X1). For example, multiple pairs of drive rollers 530 are arranged in position.

[0051] The bag making apparatus further includes at least one heat sealer 54 and 56 disposed downstream of the temporary fixer 52 to heat-seal the webs 2 to 4 during every intermittent feed cycle. In this example, a longitudinal sealer 54 and a cross sealer 56 are provided.

[0052] The longitudinal sealer 54 heat-seals the webs 2 to 4 in their longitudinal direction during every pause phase in the intermittent feed to form first sealed sections 13 (see Fig. 1A, Fig. 6A) along the opposite side edges of the webs 2 to 4. As described above, the webs 21, 31, and 41 are made of low-melting-point material. Therefore, as is clear from the relative positions of the respective webs 2 to 4 in Fig. 6B, the four layers of the webs 20, 21, 40, and 41 are integrally welded, and the four layers of the webs 30, 31, 40, and 41 are integrally welded. On the other hand, the two facing surfaces of the folded outer gusset web 40 are the high-melting-point first surface layers and thus are not welded to each other. This is also true for the subsequent cross seal.

[0053] The longitudinal sealer 54 may sandwich them between heat seal bars to heat-seal them. Here, it is preferable to use heat seal bars longer than twice the longitudinal dimension H (Fig. 6A) of the bag 1 (corresponding to the intermittent feed pitch). This enables the longitudinal sealer 54 to heat-seal the same section at least twice.

[0054] The cross sealer 56 heat-seals the webs 2 to 4 in their width direction during every pause phase in the intermittent feed to form the second sealed sections 14 (see Fig. 1A, Fig. 6A) which extend over the entire width of the webs 2 to 4. At this time, the inner panel webs 21 and 31 are welded to each other in the area where the web 4 is absent.

[0055] This example cross sealer 56 also forms the third sealed sections 15 (see Fig. 1A, Fig. 6A). For this purpose, the cross sealer 56 may use substantially K-shaped heat seal bars 560, as illustrated in Fig. 6C. Alternatively, the cross sealer 56 may use a straight heat seal bar 561 for forming the second sealed section 14 and a bifurcated heat seal bar 562 for forming the third sealed sections 15, as illustrated in Fig. 6D.

[0056] The root portion of the heat seal bar 560 or the bifurcation of the heat seal bar 562 is used for heat-sealing the central section of the webs 2 and 3, i.e., the section where the web 4 is absent. This area has fewer layers of webs compared to the surrounding area, resulting in a step. This step can cause sealing defect. Additional point seal may be applied to this section to prevent such sealing defect.

[0057] The bag making apparatus further includes a longitudinal cooler 55 disposed downstream of the longitudinal sealer 54, and a cross cooler 57 disposed downstream of the cross sealer 56. During every intermittent feed cycle, the longitudinal cooler 55 cools the first sealed sections 13, and the cross cooler 57 cools the second and third sealed sections 14 and 15. This cooling step smooths the sealed surface, providing a high-quality finished sealed surface.

[0058] The bag making apparatus further includes a slit device 58 disposed downstream of the heat sealers 54 and 56 and the cooler 55 and 57 to slit the webs 2 to 4 along the opposite side edges of the webs 2 and 3. The slit device 58 includes slitters positioned on the opposite sides of the webs 2 and 3. Therefore, as the webs 2 to 4 are fed, they are slit by the slitters along the opposite side edges of the web 2 and 3. The wastes generated during this process are wound to be collected by well-known means. The new edges of the webs 2 to 4 resulting from the slitting exhibit high straightness. Consequently, the opposite side edges (the edges of the first sealed sections 13) of the shaped bag 1 also exhibit high straightness.

[0059] The bag making apparatus further includes a cross cutter 59 disposed downstream of the slit device 58 to cross-cut the webs 2 to 4 in their width direction during every intermittent feed cycle, to shape a double-layer bag 1. Specifically, the cross cutter 59 cross-cuts the webs 2 to 4 in their width direction using a blade during every intermittent feed cycle, to obtain the portion cut out from the webs 2 to 4 as the double-layer bag 1 illustrated in Fig. 1A and Fig. 6A. This cross-cutting position is located within the second sealed section 14 of the webs 2 to 4, more specifically, the centerline of the cross seal area CS, as indicated by the reference numeral CR in Figs. 4A and 4B.

[0060] The bag 1 completed by the cross-cutting is conveyed by a conveyor (not shown).

[0061] With reference to Figs. 7A to 9E, a configuration of a gusset former 6 (an example of a web former) for forming and supplying a double-layer gusset web 4 (an example of a double-layer web folded in half) will be described. The exemplary bag making apparatus includes two gusset formers 6. One gusset former 6 supplies the web 4 from one side of the webs 20 to 31, as indicated by the arrow R1 in Fig. 2B. The other gusset former (not shown) supplies the web 4 from the other side of the webs 20 to 31, as indicated by the arrow R2. The configurations of both gusset formers are symmetrical with respect to the direction X1. Therefore, the former gusset former 6 is described, and the description of the latter gusset former is omitted.

[0062] In the gusset former 6 illustrated in Figs. 7A and 7B, two rolls 40' and 41' are installed. The roll 40' is formed by an outer gusset web 40 (an example of a first web) being wound, from which the outer gusset parts 110 of the double-layer gussets 11 of the bags 1 will be formed. The roll 41' is formed by an inner gusset web 41 (an example of a second web) being wound, form which the inner gusset parts 111 will be formed.

[0063] The material and composition of the outer gusset web 40 and the inner gusset web 41 are described above. In this example, the roll 40' is formed by the laminate structure web 40 being wound with its higher-melting-point first surface layer oriented outward and with its lower-melting-point second surface layer oriented inward.

[0064] The gusset former 6 includes inclined plates 60 and 61 provided for the respective webs 40 and 41. Fig. 9A is a sectional view as viewed from the arrow S1 in Fig. 7A, and Fig. 9B is a sectional view as viewed from the arrow S2 in Fig. 7A. The webs 40 and 41 are continuously unwound from their rolls 40' and 41', fed at a constant speed in their longitudinal direction to the inclined plates 60 and 61, and redirected from the upward direction Z1 to the horizontal direction Y1 by the inclined plates 60 and 61, respectively. The horizontal direction Y1 is perpendicular to the feed direction X1 of the webs 20 to 31 used for the double-layer panels 10. For this purpose, the bag making apparatus (gusset former 6) includes first and second continuous feeders 690 and 691 (illustrated only in Fig. 8). The first / second continuous feeder 690 / 691 is provided for the web 40 / 41, located downstream of the inclined plate 60 / 61 and upstream of the first / second stationary rollers 621 / 631 to continuously feed the web 40 / 41 in its longitudinal direction. For example, the first and second continuous feeders 690 and 691 each include a pair of drive rollers.

[0065] The gusset former 6 further includes a first tension adjuster 62 for the outer gusset web 40, disposed downstream of the inclined plate 60, and a second tension adjuster 63 for the inner gusset web 41, disposed downstream of the inclined plate 61. The webs 40 and 41 are redirected to the horizontal direction Y1 by the inclined plates 60 and 61, and then fed through the first and second tension adjusters 62 and 63, respectively.

[0066] The first tension adjuster 62 switches the web 40 from the continuous feed to the intermittent feed and appropriately controls the tension of the web 40, so that the web 40 is intermittently fed without slack or meandering. The second tension adjuster 63 switches the web 41 from the continuous feed to the intermittent feed and appropriately controls the tension of the web 41, so that the web 41 is intermittently fed without slack or meandering. The tension control of the web 40 using the first tension adjuster 62 and the tension control of the web 41 using the second tension adjuster 63 are independent of each other.

[0067] The first tension adjuster 62 in the embodiment is a first dancer mechanism which includes a first dancer roller 620 for engaging with the web 40 to apply tension to the web 40, and two first stationary rollers 621 disposed upstream and downstream of the first dancer roller 620 in a stationary manner to guide the web 40 for engaging the web 40 with the first dancer roller 620.

[0068] As illustrated only in Fig. 8, which is a detailed view of the region Q in Fig. 7, the first tension adjuster 62 further includes a first actuator 622 for supporting the first dancer roller 620 for linear shift (in the left-and-right direction in Fig. 8) of this roller and for biasing the first dancer roller 620 towards the web 40, a first sensor 623 for detecting the position of the first dancer roller 620, and a first controller 624 (including one or more processors) for controlling the first continuous feeder 690.

[0069] The first dancer roller 620 shifts left or right in Fig. 8 as the web 40 is intermittently fed by the intermittent feeder 53. During this shift, the first sensor 623 is detecting the position of the first dancer roller 620. Then, the first controller 624 changes the feed speed of the web 40 (the rotational speed of its pair of drive rollers) via the first continuous feeder 690 based on the measurements from the first sensor 623. Through this series of controls, the first controller 624 maintains the shift of the first dancer roller 620 within the predetermined range, thereby adjusting the tension of the web 40 while appropriately switching the web 40 from the continuous feed to the intermittent feed.

[0070] The second tension adjuster 63 in the embodiment is a second dancer mechanism having a configuration similar to that of the first dancer mechanism, and thus includes a second dancer roller 630, second stationary rollers 631, a second actuator 632, a second sensor 633, and a second controller 634 (including one or more processors), as illustrated in Fig. 8.

[0071] The second sensor 633 is detecting the position of the second dancer roller 630 which is shifting as the web 41 is intermittently fed by the intermittent feeder 53. The second controller 634 then changes the feed speed of the web 41 (e.g., the rotational speed of the continuous feed roller pair) via the second continuous feeder 691 based on the measurements from the second sensor 633, thereby adjusting the tension of the web 41 while appropriately switching the web 41 from the continuous feed to the intermittent feed.

[0072] The first and second tension adjusters 62 and 63 are not limited to the dancer mechanisms; other configurations than the dancer mechanisms may be adopted. Alternative to the above embodiment, the first and second controllers 624 and 634 may be constituted by a single controller, which controls the tension of the web 40 and the tension of the web 41 independently of each other.

[0073] The webs 40 and 41 are intermittently fed by the intermittent feeder 53 as described above. In addition to this feeder, the gusset former 6 may also include an additional intermittent feeder (not shown) which includes an appropriate number of pair of drive rollers and servo motors having the similar configurations to those of the intermittent feeder 53 of the bag making apparatus. The feed pitch of this intermittent feed, which is indicated by the reference numeral P in Fig. 7A, is set equal to that of the intermittent feed of the webs 20 to 31 and thus corresponds to the longitudinal dimension H (Fig. 6A) of bag 1. Furthermore, the timings of both intermittent feeds are also set to be mutually equal.

[0074] The gusset former 6 further includes a guide 64 disposed downstream of the tension adjusters 62 and 63, a single triangular plate 65 disposed downstream of and adjacent to the guide 64, a pair of crease rollers 66 disposed downstream of the triangular plate 65, a temporary fixer 67 for the webs 40 and 41, disposed downstream of the pair of crease rollers 66, and a puncher 68 disposed downstream of the temporary fixer 67. The guide 64 in the embodiment is a guide roller. These components 64 to 68 are arranged in the space created by and between the two inner panel webs 21 and 31 before being superposed, upstream of the pair of superposing rollers 50 (e.g., Fig. 2A).

[0075] The webs 40 and 41, after being fed through the tension adjusters 62 and 63, respectively, are fed sequentially through the guide 64 and the triangular plate 65. As the webs 40 and 41 are fed, they are first superposed on each other by the guide 64 at the guide 64, and then guided to the triangular plate 65 in the superposed state. At this time, the lower-melting-point second surface layer of the outer gusset web 40 contacts the inner gusset web 41.

[0076] Fig. 9C is a sectional view as viewed from the arrow F in Fig. 7A, and Fig. 9D is an enlarged sectional view as viewed from the arrow J in Fig. 9C. As illustrated in Figs. 7A, 9C, and 9D, the webs 40 and 41, which have been superposed on each other by the guide 64, are guided by the triangular plate 65 to be folded in half along the fold line 42 (Fig. 9C) extending in their longitudinal direction as they are fed, so that the folded outer gusset web 40 is interposed between the folded inner gusset web 41 as illustrated in Fig. 7A. The webs 40 and 41 are then fed through the pair of crease rollers 66, the pair of crease rollers 66 completes the folding and emphasizes the crease during this feed. Passing the webs 40 and 41 through the guide 64 and the triangular plate 65 causes the webs 40 and 41 to be redirected from the direction Y1 to the direction X1.

[0077] The double-layer gusset web 4 has been formed in this way. The fold line 42 coincides with the widthwise centerline of the webs 40 and 41. The reference numeral 43 in Figs. 7A and 9D designates the folded edge 43 of the double-layer gusset web 4, which is formed on the fold line 42. The reference numeral 44 designates the open edges of the double-layer gusset web 4. The two facing surfaces of the folded web 40 are the high-melting-point first surface layer.

[0078] The gusset temporary fixer 67 temporarily fixes the webs 40 and 41 by means of heat-sealing or ultrasonic-sealing during every intermittent feed cycle, to form the point sealed section 18 (see Fig. 9E, which is an enlarged view of the area G in Fig. 7A). This prevents misalignment of the webs 40 and 41. The position of the point sealed section 18 is, for example, within the cross seal area CS described above.

[0079] The puncher 68 punches holes 19 (Fig. 9E) for heat-sealing in the double-layer gusset web 4 during every intermittent feed cycle. The positions of the holes 19 are within the cross seal area CS. Furthermore, the holes 19 are formed on both sides with respect to the cross cut position CR described above, for example.

[0080] For example, the puncher 68 may use punch blades to punch the holes 19 in the web 4. The puncher 68 includes a suction unit (not shown) to suction the wastes generated by punching the holes 19, as in the well-known puncher. The puncher 68 also includes a waste detection unit (not shown) which detects whether a waste is adhered to the web 4 without being suctioned using a sensor and outputs a warning when detecting a waste adhered to the web 4.

[0081] As described above, the double-layer gusset web 4 is then interposed between the inner panel webs 21 and 31 when the webs 20 to 31 for the double-layer panels 10 are superposed on each other at the pair of superposing rollers 50. Also, as described above, at this time, the open edges 44 align with one side edges of the webs 20 to 31 and the folded edge 43 is positioned inward as illustrated in Fig. 2B.

[0082] In this example, when the cross sealer 56 heat-seals the webs 2 to 4 in their width direction thereof, the point sealed section 18 is completely contained within and integrated into the second sealed section 14 to disappear, and the inner panel webs 21 and 31 are welded to each other through the holes 19.

[0083] In general, folding both the inner gusset web and the outer gusset web with a single triangular plate, as in Patent Document 1, may cause one of them to sag or meander, which may result in poor finish of the double-layer gusset web.

[0084] To address this problem, the gusset former 7 in Fig. 10A according to the related art includes triangular plates 70 and 71 provided for the respective webs 40 and 41, and a disc-shaped rotatable guide plate 72 disposed downstream of the triangular plates 70 and 71. The gusset former 7 then folds the web 40 in half using the triangular plate 70 and the web 41 in half using the triangular plate 71, and then aligns the folded edges of both webs 40 and 41 using the guide plate 72 with each other. However, the combination of the two triangular plates 70 and 71 and the disc-shaped guide plate 72 may cause a gap 45 to be formed between the web 40 and the web 41, as illustrated in Fig. 10B, which thus may adversely affect the finished quality of the double-layer bags 1.

[0085] The gusset former 6 according to the present application folds the superposed webs 40 and 41 using the single triangular plate 65 as described above, however, in its upstream zone, the first and second tension adjusters 62 and 63 control the tension of the web 40 and the tension of the web 41 independently of each other, respectively. Therefore, the problem of the prior art that the webs 40 and 41 sag or meander during the formation of the double-layer gusset web 4 does not occur. Furthermore, folding the superposed webs 40 and 41 in half together simultaneously prevents the gap 45 described in the related art from occurring.

[0086] Therefore, the gusset former 6 according to the present application can form the double-layer gusset web 4 with a higher quality finish than the prior art or related art. Consequently, the bag making apparatus in the present application with this gusset former 6 can provide double-layer bags 1 with higher quality.

[0087] Similar to Patent Document 2, the above double-layer bag 1 may be used, for example, as an inner bag for a bag-in-box.

[0088] Alternative to the laminated structure, each of the webs 20, 30 and 40 may consist of a film made of mono-material and medium ink partially or fully applied to the film to inhibit heat seal. Each of the webs 20 to 41 may include paper as a base and resin partially or fully coated onto the paper. It would be appreciated by those skilled in the art that, as long as the double-layer bags 1 can be made, the webs 20 to 41 are not limited to the example configurations and materials described above.

[0089] Alternatively, the webs 20 and 30 may be formed by slitting a wide web unwound from a single roll. The webs 21 and 31 may also be formed by slitting a wide web unwound from a single roll.

[0090] The primary role of the pair of superposing rollers 50 is to converge the feed lines for the webs 2, 3, and 4, not to feed the webs 2, 3, and 4. Therefore, the pair of superposing rollers 50 does not have to nip the webs 2, 3, and 4, and its force for nipping may be very weak or even zero. Conversely, it should be taken care that excessive force for nipping may cause misalignment of the laminated body of the webs 2, 3 and 4 among them.

[0091] In the above embodiments, the double-layer web formed by the web former 6 is used as a double-layer gusset web. In other embodiments, the double-layer web formed by the web former 6 having the same structure as above is used as a double-layer panel web folded in half.

[0092] In one of these alternative embodiments, the folded double-layer panel web is formed by the web former 6, and then subject to at least a heat-sealing process and a cross-cutting process by a bag making apparatus, so that the double-layer bags without any gussets are made. This double-layer bag includes a folded outer panel and a folded inner panel interposed between the folded outer panel, wherein the outer panel is formed from the second web 41 of the double-layer panel web and the inner panel is formed from the first web 40 of the double-layer panel web. In order to implement the heat-sealing process, the alternative embodiment uses material with a higher melting point for the outer layer of the second web 41, material with a lower melting point for the inner layer of the second web 41, and material with a lower melting point for the first web 40.

[0093] The bag making apparatus according to the present application may make double-layer bags each having a zipper as an alternative to or in addition to the spout 12. The bag making apparatus according to the present application may also make double-layer bags each with a double-layer gusset functioning as a top gusset or a bottom gusset instead of the double-layer gussets 11 functioning as the side gussets as illustrated above. That is, bag making using the double-layer gusset web(s) 4 as a top gusset and / or bottom gusset may be implemented.EXPLANATIONS OF LETTERS OR NUMERALS

[0094] 1 double-layer bag 10 double-layer panel 11 double-layer gusset 12 spout 17 hole for spout 19 hole for heat-sealing 2 first double-layer panel web 20 first outer panel web 21 first inner panel web 3 second double-layer panel web 30 second outer panel web 31 second inner panel web 4 double-layer gusset web (an example of double-layer web folded in half) 40 outer gusset web (an example of first web) 41 inner gusset web (an example of second web) 42 fold line 50 pair of superposing rollers 51 spout attacher 510 guide roller 511 temporary fixing unit 512 punching unit 513 attaching unit 53 intermittent feeder 54 longitudinal sealer (an example of heat sealer) 56 cross sealer (an example of heat sealer) 59 cross cutter 6 web former (gusset former) 62 first tension adjuster (first dancer mechanism) 620 first dancer roller 63 second tension adjuster (second dancer mechanism) 630 second dancer roller 64 guide (guide roller) 65 triangular plate 67 temporary fixer

Examples

Embodiment Construction

[0021]The embodiments of the present application will now be described with reference to the drawings. The following embodiments are merely examples of the present inventions.

[0022]Fig. 1A illustrates an example double-layer bag 1. The double-layer bag 1 includes two double-layer panels 10 facing each other. As illustrated in Fig. 1B, which is a sectional view, each of the double-layer panels 10 consists of an outer panel part 100 and an inner panel part 101 superposed on each other. A storage space is formed by and between these two double-layer panels 10. The two inner panel parts 101 face each other and are interposed between the two outer panel parts 100.

[0023]The double-layer bag 1 further includes two double-layer gussets 11. The two double-layer gussets 11 form a pair, are folded to be interposed between the two double-layer panels 10, and extend along the opposite side edges of the double-layer panels 10. That is, the example double-layer gussets 11 function as side gussets ...

Claims

1. A web former for use in making double-layer bags and for forming a double-layer web folded in half and comprising a first web and a second web, the web former comprising: a first tension adjuster configured to control tension of the first web being fed in a longitudinal direction of the first web; a second tension adjuster configured to control tension of the second web being fed in a longitudinal direction of the second web independently of the first tension adjuster; a guide disposed downstream of the first and second tension adjusters to guide the first web and the second web downstream while superposing the first web and the second web on each other; and a single triangular plate disposed downstream of the guide to fold the first and second webs superposed by the guide, in half along a fold line extending in the longitudinal direction of the first and second webs.

2. The web former according to claim 1, wherein the web former is a gusset former for forming a double-layer gusset web as the double-layer web, the double-layer gusset web comprising an outer gusset web as the first web and an inner gusset web as the second web.

3. The web former according to claim 1, wherein the first tension adjuster is further configured to switch the first web from continuous feed to intermittent feed, and the second tension adjuster is further configured to switch the second web from continuous feed to intermittent feed.

4. The web former according to claim 1, wherein the first tension adjuster is a first dancer mechanism, wherein the second tension adjuster is a second dancer mechanism, wherein the first dancer mechanism comprises a first dancer roller for engaging with the first web to apply tension to the first web, and wherein the second dancer mechanism comprises a second dancer roller for engaging with the second web to apply tension to the second web.

5. The web former according to claim 1, further comprising a temporary fixer disposed downstream of the triangular plate and configured to temporarily fix the first web and the second web to each other.

6. The web former according to claim 1, wherein the guide is a guide roller.

7. A bag making apparatus for successively making double-layer bags each comprising a first double-layer panel, a second double-layer panel, and a double-layer gusset, the bag making apparatus comprising: an intermittent feeder configured to intermittently feed a first outer panel web, a first inner panel web, a second outer panel web, and a second inner panel web in a longitudinal direction thereof; a pair of superposing rollers for superposing the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel web on each other in this order; the web former according to claim 2, the web former being configured to supply the double-layer gusset web to interpose the double-layer gusset web between the first inner panel web and the second inner panel web in the longitudinal direction when the first outer panel web, the first inner panel web, the second inner panel web, and the second outer panel web are superposed on each other at the pair of superposing rollers; at least one heat sealer disposed downstream of the pair of superposing rollers and configured to heat-seal the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web during every intermittent feed cycle; and a cross cutter disposed downstream of the at least one heat sealer and configured to cross-cut the first and second outer panel webs, the first and second inner panel webs, and the double-layer gusset web in a width direction thereof during every intermittent feed cycle to shape a double-layer bag wherein the first double-layer panel is formed from the first outer panel web and the first inner panel web, the second double-layer panel is formed from the second outer panel web and the second inner panel web, and the double-layer gusset is formed from the double-layer gusset web.

8. The bag making apparatus according to claim 7, further comprising a spout attacher disposed downstream of the pair of superposing rollers and upstream of the at least one heat sealer, and configured to attach a spout to the first outer panel web and the first inner panel web superposed on each other during every intermittent feed cycle, the spout attacher comprising: a plurality of guide rollers for temporarily separating the second outer panel web, the second inner panel web, and the double-layer gusset web from the first outer panel web and the first inner panel web to create a temporary separation zone; a temporary fixing unit disposed in the temporary separation zone and configured to temporarily fix the first outer panel web and the first inner panel web to each other; a punching unit disposed downstream of the temporary fixing unit in the temporary separation zone and configured to punch a hole for the spout in the first outer panel web and the first inner panel web; and an attaching unit disposed downstream of the punching unit in the temporary separation zone and configured to insert the spout into the hole and attach the inserted spout to the first outer panel web and the first inner panel web by heat-sealing.

9. The bag making apparatus according to claim 7, wherein the web former further comprises a puncher configured to punch a hole for heat-sealing in the double-layer gusset web, wherein the at least one heat sealer is configured to heat-seal the first and second inner panel webs to each other through the hole for heat-sealing.

10. A web forming method for forming a double-layer web folded in half and comprising a first web and a second web for making double-layer bags, the method comprising: feeding the first web in a longitudinal direction of the first web; feeding the second web in a longitudinal direction of the second web; controlling tension of the first web using a first tension adjuster; controlling tension of the second web using a second tension adjuster independently of the controlling the tension of the first web using the first tension adjuster; guiding the first web and the second web downstream while superposing the first and second webs on each other using a guide located downstream of the first and second tension adjusters, and folding the superposed first and second webs in half along a fold line extending in the longitudinal direction of the first and second webs using a single triangular plate located downstream of the guide, to interpose the folded first web between the folded second web.

11. The web forming method according to claim 10, wherein the first web comprises a first surface layer and a second surface layer having a lower melting point than a melting point of the first surface layer, and the second web has a lower melting point than the melting point of the first surface layer, and wherein the first web and the second web are folded in half along the fold line by the triangular plate to contact the second surface layer with the second web.

12. The web forming method according to claim 10, wherein the first web is unwound from a first roll and continuously fed in the longitudinal direction thereof, wherein the second web is unwound from a second roll and continuously fed in the longitudinal direction thereof, wherein the first web is switched from continuous feed to intermittent feed by the first tension adjuster, and wherein the second web is switched from continuous feed to intermittent feed by the second tension adjuster.

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