JP3071636B2 - Method for producing square bottom paper bag with closure flap - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method of manufacturing a square bottom paper bag with a closing flap, and more particularly to an improved method of manufacturing a square bottom paper bag with a closing flap having an adhesive band coated with release paper.

[0002]

2. Description of the Related Art A method of manufacturing a square bottom paper bag with a closing flap having an adhesive band coated with a release paper is disclosed, for example, in Japanese Patent Publication No. 5-77507 (see FIGS. 1 and 5 of the publication). The square bottom paper bag made by the square bottom bag making machine is sent in the longitudinal direction of the bag body with the open end of the bag at the front, and the front edge of the bag is cut by an ear dropping cutter roll with cutting blades arranged in an eight-shape. With a cutter roll having a straight half-cut blade extending in the width direction of the bag, after cutting the left and right corners of the open end of the bag across the four layers of the fold front wall, the fold back wall, and the bag back wall, A method of forming a closing flap protruding from the front wall on the rear wall of the square bottom bag by cutting off the other three walls, leaving only the rear wall of the bag serving as a closing flap separated by the ear dropping. It has been disclosed.

[0003]

However, the so-called half-cut blade has a certain thickness of each laminated sheet and ensures that only the adhesive label base paper is used, as in the case of punching only the adhesive label base paper laminated on release paper. It is suitable for applications where there is no problem even if a slight scratch is made on the release paper. However, as shown in FIG. 2, four layers are provided at one side end including the body sticking portion, and three layers are provided at the other side end. Since the number of layers to be punched is different from the single layer at the layer and the central part, the resistance of the sheet side at the time of punching is different, causing undesirable cuts in the flap part and leaving uncut parts in the cut part. Is not stable,
Productivity was often impaired.

[0004] The present invention has been made in view of the above circumstances, and an object thereof is to provide an undesired cut or the like at the base of a closing flap formed on a front wall or a rear wall of a bag, and to provide an opening end other than the opening flap. It is an object of the present invention to provide an improved method for producing a square bottom paper bag with a closing flap which can surely cut off the three layers.

[0005]

According to the present invention, a square-bottomed paper bag made by a known square-bottom bag making machine is inserted into a bag in the width direction of the bag.
That is, the bag is fed in a direction perpendicular to the length direction, and only the wall on which the closing flap of the bag is formed is bent outward, and the other 3
This problem has been solved by separating the layers and feeding them, and cutting off the remaining three layers with a rotary knife.

That is, in order to solve the above-mentioned problems, the method of the present invention is to provide a square-bottomed paper bag having V-shaped folds on both left and right sides of the bag body and having an opening edge cut straight. A first step of feeding one sheet at a time at a constant interval in a direction perpendicular to the direction,
Opening from the side edges near the center in the longitudinal direction of the bag body by a distance corresponding to the size of the expected closing flap from the opening edge across the front wall of the fold, the rear wall of the fold, and the back wall of the bag. A second step of cutting diagonally inward toward the edge, and bending only the bag front wall or the bag rear wall separated by the cutout outward, separating and sending the remaining three layers, The three layers are cut off by a rotary knife parallel to the opening edge at a position near the center in the longitudinal direction of the bag body at a distance corresponding to the size of the expected closing flap from the opening edge. The third step of forming the closing flap by projecting the front wall or the rear wall of the bag from the other wall, and the fourth step of providing an adhesive band coated with release paper on the inner surface of the closing flap are successively performed. It is characterized by performing.

Prior to the third step, the bag wall forming the closing flap is bent upward or downward, that is, outwardly, and sent separately from the other three layers. It is preferable to include a step of creasing a portion of the bag wall closer to the center of the bag body from the opening edge of the bag wall close to the center of the bag body in parallel with the opening edge, and the fourth step is a release paper. Applying a pressure-sensitive adhesive to one surface of the continuous band, and cutting the continuous band of the release paper coated with the pressure-sensitive adhesive into a fixed size, and attaching the continuous band to the inner surface of the closing flap. preferable.

[0008]

According to the method of the present invention, in the first step, the square bottom bags made by a known square bottom bag making machine are fed in the width direction, that is, in the direction perpendicular to the length direction. The two side edges of the square bottom paper bag are rotated with a rotary knife over four layers of the front wall of the bag, the front wall of the pleat, the rear wall of the pleat, and the rear wall of the bag, at a distance corresponding to the size of the expected closing flap from the opening edge, When the bag body is cut obliquely inward toward the opening edge from the positions of the both side edges near the longitudinal center of the bag body, in the third step, only the bag front wall or the bag rear wall of the cut-off portion is moved upward or downward. It is possible to bend downwards, i.e., outward and separate from the other three layers, so that the remaining three layers are scheduled from the opening edge without unnecessary flaws or cuts at the root of the closing flap. A distance corresponding to the size of the closing flap is located near the center in the length direction of the bag. In this position, the bag can be cut off with a rotary knife in parallel with the opening edge, and the effect of projecting the previously separated bag front wall or bag rear wall from the other side wall to form a closing flap is achieved. You.

In the third step, the bag forming the closing flap is bent before or after the bag wall forming the closing flap is separated upward from the other three layers. When a crease is cut from the opening edge of the wall toward the center of the bag by a predetermined size of the closing flap in parallel with the opening edge, the bag wall is separated from the other three layers. It is easy to bend, and the effect that the closing flap of the completed square bottom paper bag is bent to make it easy to close the square bottom paper bag is achieved.

Further, in the fourth step, an adhesive is applied to one surface of the continuous band of the release paper, and this is cut to a fixed size.
When applied to the inner surface of the closing flap, the adhesive applied on the release paper is transferred to the closing flap and fixed on the flap, so that the adhesive band coated with the release paper on the inner surface of the closing flap is inexpensive. Is achieved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, two embodiments of the method of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 shows an embodiment of the method of the present invention (hereinafter referred to as a first embodiment).
FIG. 2 is a cross-sectional view of the bag along the line AA ′ in FIG. 1, FIG. 3 is a perspective view for explaining the second step, 4 is a perspective view for explaining the third step, FIG. 5 is a schematic perspective view for explaining a means for performing the third step shown in FIG. 4, and FIGS. Sectional views taken along the line B 'and the line CC' also show the state of the bag at each location. FIG. 8 is a perspective view for explaining the fourth step, and FIG.
FIG. 9 is a schematic side view for explaining a means for performing the fourth step shown in FIG. 8.

In the figure, reference numeral 1 denotes a bag, 11 denotes a front wall of the bag, and 12 denotes a bag.
Is a front wall of the fold, 13 is a rear wall of the fold, 14 is a rear wall of the bag, 15 is a bottom portion, 16 is an open edge, 17 is a side edge, 18 is a closing flap, 19 is a cut line, 1a and 1b are cut-off portions. , 1p is a body sticking part, 2 is a feed chain, 21 is a claw, 3 and 4 are rotary knives, 31 and 41 are blades, 42a and 42b are creased rollers,
43 is a vacuum guide plate, 44 is a guide plate, 45 is a fixed blade, 5 is winding of release paper, 5a is a continuous band of release paper, 5
b is a piece of release paper, 51 is a feed roller, 52 is a vacuum drum, 53a is a rotary knife, 53b is a fixed blade, 54
Is a hot melt applicator, and 55 is an adhesive.

Referring to FIGS. 1 and 2, the first embodiment of the present invention will be described.
In the process, on both sides of the bag body 1 having a bag front wall 11 and a bag rear wall 14, the bag body 1 has a fold portion formed of a V-shaped fold front wall 12 and a fold back wall 13, and the bottom portion 15 is folded into a rectangle. A well-known square bottom paper bag (bag body 1) whose opening edge is cut in a straight line
Are sent to the second step at regular intervals by one bag in a direction perpendicular to the length direction thereof by the feed chain 2 having the claws 21. In addition, the said square-bottom paper bag may be what was made with a well-known square-bottom bag-making machine, or what was made manually. Further, in order to supply the bags one by one to these moving means, a known automatic vacuum feeder may be used, or the bags may be supplied manually.

As shown in FIG. 3, in the second step of the present embodiment, both side edges 17 of the bag 1 are slid by the rotary cutter 3 having blades 31 arranged obliquely at two places around the periphery. Front wall 1
1. Closing flap 1 scheduled from an opening edge 16 over four layers of a front fold wall 12, a rear fold wall 13, and a rear sack wall 14.
8 is cut off obliquely inward toward the opening edge 16 from a position near the center in the length direction of the bag 1 by a distance corresponding to the dimension f of 8. In this embodiment, the counterpart of the rotary knife 3 may be a rotary knife that rotates in synchronization with the rotary knife or a fixed blade. The cut-off portion 1a is removed by a suitable means such as suction. Bag 1 after completion of the second step
Is sent to the third step.

Referring to FIG. 4, in the third step of this embodiment, the bag 1 is first passed between the creasing rollers 42a and 42b, and the dimensions of the closing flap expected from the opening edge 16 are set. A streak 19 is formed parallel to the opening edge 16 over the entire width of the bag 1 at a position near the center in the length direction of the bag 1 by a distance corresponding to f. This involves bending the bag back wall 14 forming the closure flap 18 downwardly in the next stage of the third step to facilitate separation from the other three layers, and folding the closure flap 18 of the finished square bottom paper bag. To make it easier to close.

In the next stage of the third step of this embodiment, the second step
Among the bag front wall 11, fold front wall 12, fold back wall 13, and bag back wall 14 at the open ends separated by cutting off the side edge 17 in the process, only the bag back wall 14 is bent downward, The other three
The layers (11, 12, 13) are fed separately, and the remaining three layers are separated from the opening edge 16 by a distance f corresponding to the size of the intended closing flap 18 in the longitudinal center of the bag 1. At the close position, the rotating knife 4 is parallel to the opening edge 16.
Disconnect with

One means for carrying out the third step is shown in FIGS.
As shown in FIG. First, the portion serving as the closing flap 18 of the bag rear wall 14 is sucked and bent downward by the vacuum guide plate 43, and is separated from the bag front wall 11, the fold front wall 12, and the fold rear wall 13 to be fed. As a result, the separated portion of the bag rear wall 14 passes beneath the guide plate 44 and is bent substantially vertically downward along the guide plate. On the other hand, the three layers of the bag front wall 11, the pleat front wall 12, and the pleat rear wall 13 pass over the fixed blade 45, and at this time, the blade 41 of the rotary knife 4
Thereby, it is cut along the edge of the fixed blade 45. In this way, the closing flap formed on the bag rear wall 14 is not damaged by the blade 41 of the rotary knife 4 because there is no chance that the bag rear wall 14 comes into contact with the rotary knife 41.

Referring to FIGS. 8 and 9, the fourth embodiment of the present invention will be described.
The steps will be described. In the fourth step, a (hot-melt) pressure-sensitive adhesive 55 is applied to the inner surface of the closing flap 18 formed in the third step, and a release paper piece 5b cut to a fixed size is attached. FIG. 9 is a schematic side view of one means for performing the fourth step of the present embodiment, and shows a continuous band 5 of release paper.
a is a pair of feed rollers 51 from the release paper winding 5 being braked by a suitable brake (not shown).
Is wound at a constant speed by the vacuum drum 52
Sent to Vacuum drum 52 feed roller 5
1, the release paper is adsorbed for about 180 ° from a position almost directly below to a position where the release paper piece 5b is stuck on the closing flap 18, and rotates at a peripheral speed slightly higher than that of the feed roller 51. Fixed blades 53b are attached around the drum at a plurality of locations. The continuous blades 5a of the release paper are cut into fixed-size release paper pieces 5b between the rotary blades 53a.

Next, a hot-melt applicator 54 applies a (hot-melt) adhesive 55 onto the release paper piece 5b adsorbed on the vacuum drum 52. By setting the nozzle width of the hot melt applicator 54 and the time for discharging the pressure-sensitive adhesive 55 appropriately, the pressure-sensitive adhesive is not formed on the entire surface of the release sheet 5b.
When a non-coated portion having an appropriate width is provided on the peripheral edge of the paper bag, the release paper piece 5b can be easily removed when the completed square bottom paper bag is sealed.

When the release sheet 5b to which the adhesive 55 has been applied reaches the position where the suction of the vacuum drum 52 is stopped, it is attached to the inner surface of the closing flap 18 of the bag. The adhesive 55 applied on the release paper piece 5b is fixed to the inner surface (that is, the paper surface) of the closing flap 18 that is more easily fixed than the release paper surface (that is, the silicon surface).
Even when the release paper piece 5b is peeled, the adhesive 55 does not remain on the release paper surface.

Next, another embodiment of the present invention (hereinafter, referred to as a second embodiment) will be described with reference to FIGS. FIG. 10 is a schematic plan view for explaining a first step of the second embodiment of the present invention, FIG. 11 is a cross-sectional view taken along the line DD ′ of FIG. 10, and FIG. 12 is for explaining the second step. 13, FIG. 13 is a schematic perspective view for explaining the third step, FIG. 14 is a cross-sectional view taken along the line EE 'of FIG. 13, and FIG.
FIG. 16 is a partial side view as viewed from the direction of arrow F in FIG. 15, and FIG.
It is sectional drawing along the G 'line.

Reference numerals in the drawings have the same meanings as those in FIGS. 1 to 9, wherein 22 is a feed belt, 23 is a guide, 3a,
3b is a rotary knife, 32a, 32b, 32c, and 32d are drive timing belts, 46 is a lower blade roller of the rotary knife 4, 47 is a guide roller, 51a and 51b are feed rollers, and 54a and 54b are hot melt applicators. Backup rollers, 56a and 56b are water-cooled rollers, 57a and 57b are payout rollers, 58 is a vacuum belt, 59 is a press roller, and 60 is a discharge belt.

Referring to FIGS. 10 and 11, the means for performing the first step of the second embodiment includes, in addition to the feed chain 2 to which the pawl 21 is attached, a guide 23 and a diagonal toward the guide. And the bag 1 is fed by the feed belt 22, is abutted on the guide 23, is positioned in the left-right direction, and runs slower than the feed chain 2. Claw 2 on 2
1 is sent from the rear to the second step while maintaining a constant distance from the front bag 1 on the running chain 2.

Referring to FIG. 12, in the means for carrying out the second step of the second embodiment, the bag 1 is
A pair of drive timing belts 32a, 32b, 32c, 3
2d (see FIG. 13), the front and rear side edges 17 of the bag body 1 in the traveling direction are separated by separate rotating knives 3a and 3d.
b. First, the rotary knife 3a cuts off the front side edge 17 in the traveling direction of the bag 1, and then the rotary knife 3b cuts off the rear side edge 17. The rotations of the rotary knives 3a and 3b are synchronized with the feed pitch of the bag 1, and when the bags are set in bags having different bag widths, the phase of the rotary knife 3b may be adjusted.

Referring to FIGS. 13 and 14, means for carrying out the third step include two pairs of drive timing belts 32a, 32b and 32c which feed bag 1 while sandwiching it from above and below.
And 32d, a vacuum guide plate 43 for sucking the portion of the bag rear wall 14 which will be the closing flap 18 downward, and the portions sucked below the bag rear wall for the bag front wall 11, the fold front wall 12,
The guide plate 44 and the guide plate 4 which are separated from the pleat rear wall 13
4, a rotating knife 4 with blades 41 for cutting the bag front wall 11, the pleat front wall 12, and the pleat rear wall 13 separated from the bag rear wall 14, and the lower blade roller 46, and while cutting the three layers, And a guide roller 47 that holds the bag rear wall 14 by bending it downward.

Next, referring to FIG. 15 to FIG.
Means for performing the fourth step of the embodiment will be described. This means, as shown in FIG. 15, a pair of feed rollers 51a and 51b for unwinding the continuous strip 5a of the release paper from the winding 5 of the release paper at a constant speed, and on the continuous strip 5a of the unwrapped release paper. A hot-melt applicator 54 for applying a (hot-melt) adhesive with a width smaller than the width of the continuous band and intermittently for a predetermined length, and back-up rollers 54a and 54b, and an applied (hot-melt) adhesive Water-cooling rollers 56a and 56b for cooling the agent 55, a pair of feed rollers 57a and 57b for feeding a continuous band 5a of release paper having the (hot-melt) adhesive 55 cooled to a cutter comprising a rotary blade 53a and a fixed blade 53b, The rotary blade 5
Release paper piece 5 cut to fixed size between 3a and fixed blade 53b
b, which transports b on the closing flap 18 of the bag 1 on the discharge belt 60,
A press roller 59 (FIG. 17) for pressing the release paper piece 5b stuck on the closing flap 18 by the belt 58
Reference).

Until the continuous band 5a of the release paper unwound from the winding 5 is cut, the speed of each feed roller is set to 51a <51b <56a <56b <57 so as not to loosen.
a is set. In addition, the surfaces of the water-cooled rollers 56a and 56b are subjected to plasma processing using a silicon-based material so that the applied (hot-melt) adhesive does not transfer to the contacting roller surface. As shown in FIG. The roller 57a steals a central portion of the continuous band 5a of the release paper on which the adhesive 55 is not applied so as to press only the both end portions thereof. As described above, the first
Although the embodiment and the second embodiment differ in the means for carrying them out, there is no difference in the method of manufacturing the square bottom paper bag with the closing flap carried out by these means.

[0029]

According to the method of the present invention, in the first step, a square bottom bag made by a known square bottom bag making machine is fed in the width direction, that is, in the direction perpendicular to the length direction. The edges of both sides of the square-bottomed paper bag are rotated by a rotary knife over four layers of the front wall of the bag, the front wall of the fold, the rear wall of the fold, and the rear wall of the bag, for a distance corresponding to the size of the expected closing flap from the opening edge. When the bag is cut obliquely inward from the position near the center in the longitudinal direction toward the opening edge, in the third step, only the bag front wall or the bag rear wall of the cut portion is bent upward or downward. It is possible to send separately from the other three layers, without unnecessary flaws or cuts at the root of the closing flap,
The remaining three layers can be cut off by a rotary knife parallel to the opening edge at a position near the center in the lengthwise direction of the bag from the opening edge at a distance corresponding to the size of the expected closing flap. A separate bag front wall or bag rear wall can project from the other side wall to form a closure flap.

In the third step, the bag wall forming the closing flap is bent upward or downward, that is, outward, so that the closing flap is first separated from the other three layers before being sent. From the opening edge of the bag wall to be formed, when a portion close to the center of the bag body is creased in parallel with the opening edge by a predetermined size of the closing flap, the bag wall is separated from the other three layers. It is easy to bend when separated, and the closing flap of the completed square bottom paper bag can be bent to make it easy to close the square bottom paper bag.

Further, in the fourth step, an adhesive is applied to one surface of the continuous band of the release paper, and this is cut to a fixed size.
When applied to the inner surface of the closing flap, the adhesive applied on the release paper is transferred onto the closing flap and fixed on the flap, so that the inner surface of the closing flap is coated with an adhesive band coated with release paper. It can be provided at low cost. As described above in detail, according to the present invention, an undesired cut or the like is not formed at the base of the closing flap formed on the front or rear wall of the bag, and the other three layers of the opening end are reliably cut off. The present invention can provide a method of manufacturing an improved square bottom paper bag with a closing flap.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a first step of an embodiment of the method of the present invention.

FIG. 2 is a cross-sectional view of the bag taken along line AA 'of FIG.

FIG. 3 is a perspective view for explaining a second step of the present embodiment.

FIG. 4 is a perspective view for explaining a third step of the present embodiment.

FIG. 5 is a schematic perspective view for explaining one means for performing a third step of the present embodiment.

6 is a cross-sectional view taken along the line BB 'of FIG. 5, and also shows a state of the bag.

FIG. 7 is a cross-sectional view taken along the line CC ′ of FIG. 5 and also shows a state of the bag.

FIG. 8 is a perspective view for explaining a fourth step of the present embodiment.

FIG. 9 is a schematic side view illustrating one means for performing a fourth step of the present embodiment.

FIG. 10 is a schematic plan view for explaining a first step of a second embodiment of the method of the present embodiment.

FIG. 11 is a sectional view taken along line DD ′ of FIG. 10;

FIG. 12 is a schematic plan view for explaining a second step of the second embodiment.

FIG. 13 is a schematic perspective view for explaining a third step of the second embodiment.

FIG. 14 is a sectional view taken along line EE ′ of FIG. 13;

FIG. 15 is a schematic side view for explaining a fourth step of the second embodiment.

16 is a partial arrow view as seen from the direction of arrow F in FIG.

FIG. 17 is a sectional view taken along line GG ′ of FIG. 15;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... bag body, 11 ... bag front wall, 12 ... pleat front wall, 13 ... rear pleat wall, 14 ... bag rear wall, 15 ... bottom part, 16 ... opening edge, 1
7 ... side edge, 18 ... closing flap, 19 ... streak, 1
a, 1b: cut-off portion, 1p: body sticking portion, 2: feed chain, 21: claw, 22: feed belt, 23: guide, 3,
3a, 3b: rotating knife, 31: blade, 32a, 32b,
32c, 32d: drive timing belt, 4: rotating knife, 41: blade, 42a, 42b: creased roller, 43:
Vacuum guide plate, 44: guide plate, 45: fixed blade, 46: backup roller of rotary knife 4, 4
7: guide roller, 5: winding of release paper, 5a: continuous band of release paper, 5b: release paper piece, 51, 51a, 51b ...
Feed roller, 52: Vacuum drum, 53a: Rotating knife, 53b: Fixed blade, 54: Hot melt applicator, 54a, 54b: Backup roller of hot melt applicator, 55: Adhesive, 56
a, 56b: water cooling roller, 57a, 57b: feeding roller, 58: vacuum belt, 59: holding belt, 60: discharging belt.

Claims (3)

(57) [Claims] 1. A bag having folds folded in a V-shape on both left and right sides of a bag body and having open edges cut in a straight line, at regular intervals one by one in a direction perpendicular to its length direction. A first step of feeding, and a closing flap scheduled from the opening edge by crossing the side edges of the square bottom paper bag with the rotary knife to the four layers of the front wall of the bag, the front wall of the fold, the rear wall of the fold, and the rear wall of the bag. A second step of cutting obliquely inward from a position near the center in the length direction of the bag body toward the opening edge by a distance corresponding to the dimension of the bag body, and only the bag front wall or the bag rear wall separated by the cut-off. Is bent outward and sent separately from the other three layers, and the remaining three layers are shifted from the opening edge by a distance corresponding to the size of the expected closing flap toward the longitudinal center of the bag body. Cut off with a rotary knife parallel to the opening edge and project the previously separated bag front wall or bag rear wall from the other side wall. Third to form a closing flap
And a fourth step of providing an adhesive band coated with a release paper on the inner surface of the closing flap. 2. The method according to claim 1, wherein the third step is to bend the bag wall forming the closing flap outward and send it separately from the other three layers.
At a position closer to the center of the bag body in the longitudinal direction by a distance corresponding to the size of the closing flap to be opened from the opening edge serving as the tip of the closing flap of the bag wall, in parallel with the opening edge over the entire width of the bag. 2. The method for producing a square bottom paper bag with a closing flap according to claim 1, comprising a step of creasing. 3. The step of applying an adhesive to one surface of a continuous strip of release paper in the fourth step, and cutting the continuous strip of release paper to which the adhesive has been applied into a fixed size to form the closing flap. 3. The method of manufacturing a square-fed paper bag with a closing flap according to claim 1 or 2, wherein the method is affixed to an inner surface of the paper bag.