JP2715402B2 - Square bottom bag creasing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for creasing a square bottom bag for folding a square bottom portion of a paper bag.

[0002]

2. Description of the Related Art Conventionally, before the bottom of a paper bag is folded, that is, as shown in FIG. The folding flaps 1A and 1B are formed on the front and back sides of the paper cylinder 1 by inserting the fold line 2 closer thereto, and the two folding flaps 1A and 1B are folded inward by a bottom folding device (not shown) and bonded together. Although the bottom corner portion 4A of the paper bag 4 is formed, when the corner bottom portion 4A of the paper bag 4 is folded by the bottom folding device, the bottom opening of the paper cylinder 1 is opened as shown in FIG. After the folding flap 1A is once turned upside down and the front and back folding flaps 1A and 1B are developed in a plane, FIG.
As shown in (C), the front and back folding flaps 1A and 1B are each folded inward. Therefore, FIG.
As shown in (A), the folding line 3 which is a folding habit when the folding flap 1A on the front side is turned over is folded Flaps 1A and 1B.
It is necessary to engrave in parallel with the fold line 2. As described above, a creasing device shown in FIG. 21 is known as a device for engraving the fold line 2 and the fold line 3 in parallel near the bottom opening of the paper cylinder 1. This consists of a rotary drive roller 7 in which two creased blades 6, 6A are assembled in the circumferential direction at intervals while the paper cylinder 1 is being conveyed, and a receiving roller 8 in which a flexible rubber material 8A is mounted on the peripheral surface. Are arranged, and the paper cylinder 1 is conveyed and supplied between the rotation driving roller 7 and the receiving roller 8 to rotate the rollers 7 and 8 in the opposite direction to each other. 6A through the cylinder 1
A folding line 3 for turning the folding flaps 1A and 1B and the folding flap 1A on the front side is turned upside down near the bottom opening of the paper cylinder 1.

[0003]

By the way, the fold line 2 engraved on the paper cylinder 1 is formed on the front and back of the paper cylinder 1 because it has a habit when each of the front and back flaps 1A and 1B is folded inward. Although it is necessary, the folding line 3 engraved in parallel with the fold line 2 is a folding habit for folding the folding flap 1A on the front side upside down, and is originally formed only on the front side of the paper cylinder 1. Good, but in the conventional creasing device,
Two blades 6 with streaks attached to the rotary drive roller 7,
In order to press 6A against the rubber material 8A of the receiving roller 8 with the paper cylinder 1 interposed, the folding line 3 is engraved on the front and back of the paper cylinder 1,
As shown in FIG. 22, traces of the folded lines 3 which are completely unnecessary in the bottom folding process are engraved on the back side of the paper cylinder 1 in the completed paper bag 4 and remain as streaky traces 9 on the completed paper bag 4. For example, when a photograph or pattern printed on the paper bag 4 is formed, a streak 9 is formed in the photographic surface or the pattern portion, which is unsightly in appearance design. Was unsuitable for

SUMMARY OF THE INVENTION It is an object of the present invention to provide a creasing device for a square bottom bag which can leave unnecessary folding lines in the bottom folding step and eliminate unnecessary traces of the folding lines.

[0005]

According to a first aspect of the present invention, a paper cylinder is formed by gluing side edges to form a front and rear opening, and the paper cylinder is conveyed and conveyed to a bottom folding process. A first creased blade for engraving a fold line of the folding flap near the bottom opening of the paper cylinder, and a fold line for folding the fold flap on the front side of the paper cylinder in parallel with the fold line. In a creasing device for a square bottom bag provided with a second scoring blade for engraving, a blade holder for assembling the first and second scoring blades is provided, and the paper cylinder is disposed below the blade holder. A hard receiving portion is provided for abutting the first and second creased blades therebetween, and the receiving portion has the first
And a flexible rubber material to be mounted in the groove and the first creased blade sandwiching the paper cylinder with the folding flap on the front and back of the paper cylinder. And the paper tube is sandwiched between the receiving portion and the second scoring blade, and the folded line is carved only on the front surface side of the paper tube.

According to a second aspect of the present invention, the second creased blade is divided into right and left, and the left and right divided second creased blades are respectively assembled to the blade holder so as to be adjustable in height. .

[0007]

According to the first aspect of the present invention, the first creased blade is cut into the rubber material provided in the concave groove of the receiving portion, and the fold lines of the folding flap are engraved on the front and back of the paper cylinder. On the other hand, the second scoring blade for inserting the folded line of the front folding flap is completed by engraving the folded line for folding the front folding flap only on the front surface paper of the paper cylinder by abutting against the rigid receiving portion. There are no streaks on one side of the paper bag.

According to a second aspect of the present invention, one of the divided scoring blades is assembled to a blade holder so as to be lower than the other scoring blade by an amount of glue of a paper cylinder, thereby dividing the blade into left and right parts. Can be uniformly pressed against both sides of the paper cylinder.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 16 show an embodiment of the present invention.
The same parts as those in the conventional example will be described using the same reference numerals.

The creasing device of the present invention is to be incorporated into a bag making machine with a square bottom bag. In a step before folding the bottom of the paper bag 4, the paper bag 4 is folded in advance so that both sides become V-shaped inward. To form a paper cylinder 1 having front and rear openings. As shown in the schematic explanatory view of FIG. 1, the square-bottom bag making machine has a fold near a bottom opening which is a square bottom portion of a paper bag 4 at a terminal side of a supply device A for continuously supplying a paper cylinder 1. A creasing device B for forming a crease, a bottom opening device C for opening the bag bottom by adsorbing surface paper on the bottom of the bag,
A bottom folding drum 10 for sandwiching the back side paper at the bottom of the bag and rotating and transporting the paper cylinder 1 is continuously provided, and a folding line formed by the creasing device B is provided on the outer periphery of the bottom folding drum 10. From 3, a flap folding device D for folding back the front side folding flap 1A to the inside of the paper cylinder 1 and unfolding the front and back folding flaps 1A and 1B in a plane along the bottom folding drum 10 and the front and back folding flaps 1A and 1B. A gluing device E for gluing and a bottom folding device F for attaching the respective folding flaps 1A and 1B are provided side by side.

More specifically, the supply device A is provided with the configuration shown in FIG.
As shown in the figure, the driving sprocket 11 and the driven sprocket
And a pair of left and right endless conveyor chains 13 provided so as to bridge the paper cylinder 1 with the feed claws 14 attached to the conveyor chain 13 so that the bottom of the bag is oriented in the conveying direction. It is transported to the attaching, bottom folding and sticking processes.
As shown in FIG. 1, a pair of upper and lower press rollers 15 are disposed between the paper tube feeding device A and the creasing device B, and the press rollers 15 are rotated in opposite directions by a driving device (not shown). Then, by sandwiching the paper cylinder 1, both sides of the paper cylinder 1 are pressed and transferred to the folding crease device B1 in the next step.

As shown in FIG. 2, the creasing device B includes first and second creasing blades 2 each formed in a plate shape.
The upper rotating shaft 22 having 0, 21 and the respective blade 2
It comprises a lower rotating shaft 24 provided with a metallic cylindrical roller 23 as a receiving portion for 0 and 21. As shown in FIGS. 2 and 3, each of the creased blades 20 and 21 has a pair of front and rear blade holders.
25 fixed by screws 26 to its blade holder 25
Is fixed to the notch recess 27A of the disc-shaped mounting plate 27 fixed to the upper rotating shaft 22. On the other hand, on the peripheral surface of the cylindrical roller 23 fixed to the lower rotary shaft 24, a concave groove 28 is formed facing the first creased blade 20 on the right side in the drawing, which is the front side in the transport direction of the paper cylinder 1.
A pedestal 30 in which a flexible rubber material 29 is adhered in the concave groove 28, the surface of the rubber material 29 is attached to the cylindrical roller 23.
Is screwed continuously with the peripheral surface. The two rotating shafts 22,
As shown in FIG. 3, a drive gear 31 for transmitting rotation from a drive source (not shown) meshes with a transmission gear 31A fixed to one end of the lower rotation shaft 24, as shown in FIG.
The rotation of the lower rotary shaft 24 that rotates through 31A
24 and a plurality of relay gears 3 fixed to the other side of the upper rotating shaft 22
The upper rotating shaft 22 is transmitted to the lower rotating shaft 24 in the opposite direction to the lower rotating shaft 24 by being transmitted to the upper rotating shaft 22 via 2, 32A. Then, each of the creased blades 20, 21 is pressed against the bottom end of the paper cylinder 1 supplied between the rotation shafts 22, 24. At this time, the first creased blade 20 on the front side in the transport direction is provided in the concave groove 28 of the cylindrical roller 23 through the paper cylinder 1 and bites into the rubber material 29, so that the folding flaps 1 </ b> A , 1B are engraved. On the other hand, the second
Is a hard cylindrical roller via the paper cylinder 1
23, a folding line 3 for folding the front folding flap 1A is formed only on the front surface paper of the paper cylinder 1 in parallel with the folding line 2. The fold line 2 and the fold line 3
As shown in FIG. 4, the distance S from the front end side of the paper cylinder 1 to the fold line 2 is the length of each of the front and back folding flaps 1A and 1B, and when folding each of the folding flaps 1A and 1B, The interval S is set to be longer than half the opening width of the paper cylinder 1 so that the folding flaps 1A and 1B overlap each other. Also, the interval S1 between the fold line 2 and the return line 3,
That is, the interval between the creased blades 20 and 21A is set to substantially half the opening width of the paper cylinder 1. In this case, in order to correspond to various sizes of bag mouths, the mounting plate 27 is required.
The spacing between the creased blades 20, 21 can be adjusted within the notch recess 27A.

A paper cylinder 1 is provided behind the creasing device B.
A mouth creasing device B1 for folding the bag mouth side inward to reinforce the bag mouth is disposed, and the mouth creasing device B1 is provided.
Has substantially the same configuration as that of the creasing device B described above, the portions having the same functions as those of the creasing device B are denoted by the same reference numerals, and only different portions will be described. As shown in FIG. 2, a mouth creasing device B <b> 1 for creasing the bag mouth of the paper cylinder 1 is provided on a mounting plate 27 for fixing a single creasing blade 35 to the upper rotation shaft 22 via the blade holder 25. Fixed, while
A groove 29A for receiving the scoring blade 35 is formed on the outer periphery of the cylindrical roller 23 fixed to the lower rotation shaft 24. Then, the upper rotating shaft 22 is rotated in a direction opposite to that of the lower rotating shaft 24 so as to press the streaked blade 35 against the bag mouth of the paper cylinder 1 supplied between the two rotating shafts 22 and 24. As shown in the figure, a fold line 36 is formed in the paper cylinder 1 at the time of folding. Then, the fold line 2, the fold line 3 and the fold line 36 are formed by the two creasing devices B and B1.
Is transported to the bottom opening device C.

As shown in FIG. 1 and FIG. 5, the bottom opening device C has a rotating circular plate 41 fixed to the upper rotating shaft 40 and fixed to the upper rotating shaft 40 at both sides of the rotating circular plate 41. The lower ring forming a pair with the suction ring 43 and the rotating arc plate 41, which are fixed to the rotating arc plate 41, facing the opening 43A formed by cutting out the outer peripheral surface of the holding ring 42 and the rotating arc plate 41. The suction flap 1A of the paper cylinder 1 is sucked by a negative pressure generating device such as a vacuum pump (not shown) connected to the suction pad 43 and connected to the suction pad 43.
The front side flap 1A of the paper cylinder 1 is sucked along the rotation path of the suction pad 43 attached to the rotating arc plate 41. And
Almost simultaneously with this, the tip of the back side flap 1B of the opened paper cylinder 1 is clamped by a catching claw (described later) provided on the bottom folding drum 10 disposed close to the bottom opening device C, and the upper rotating shaft 40 and the bottom The folding drum 10 is rotated in the opposite direction to the
Open the bottom of the bag.

As shown in FIG. 5, the flap folding device D comprises a pair of left and right guide plates 50 for guiding both sides of the bag opening opened by the bottom opening device C.
Reference numeral 50 is fixed to a mounting rod 51 provided horizontally above the bottom folding drum 10 through a mounting arm 52 so as to be substantially horizontal. The left and right guide plates 50 include a flat plate portion 53 and a standing portion 54 that extends downward from both side ends of the flat plate portion 53. One end of the flat plate portion 53 (the bottom opening device C side) is An inclined portion 54 </ b> A gradually increasing toward the outer edge portion is formed, and the multi-end side of the flat plate portion 53 is fixed to the mounting arm 52 so as to be in contact with the outer peripheral surface of the bottom folding drum 10. Further, a linear member for pressing the central portion of the paper cylinder 1 against the outer peripheral surface of the bottom folding drum 10 is provided between the guide plates 50.
56 is fixed to the mounting rod 51 via a mounting arm 52A. The paper cylinder 1 rotated and conveyed by the bottom folding drum 10 is guided between the left and right guide plates 50 and the bottom folding drum 10, and the front side folding flap 1A sucked by the bottom opening device C is connected to each guide plate. The bottom folding drum 10 is pressed against the flat plate portion 53, and the front folding flap 1A is turned upside down from the folding line 3 by the rotation of the bottom folding drum 10. In other words, only the front side flaps 1A are turned upside down while leaving the back side flaps 1B, so that the front and back side flaps 1A, 1 are folded.
B is developed two-dimensionally along the outer periphery of the bottom folding drum 10. In this manner, the paper cylinder 1 in which the front and back folding flaps 1A and 1B are unfolded by the flap folding device D is conveyed together with the rotation of the bottom folding drum 10. At this time, each folding flap 1A,
1B, the folding flaps 1A and 1B are folded flat, and the paper cylinder 1 has a slight clearance between the curved guide regulating plate 58 and the bottom folding drum 10 provided along with the bottom folding drum 10. The paper tube 1 is stably conveyed while suppressing the rising of the paper tube 1.

As shown in FIG. 6, a sizing device E includes a tank 60 for storing starch glue or a chemical glue-based adhesive A and a sizing roller 62 having a sizing portion 61 made of synthetic rubber or the like on the outer peripheral surface.
And a relay roller 64 provided between the tank 60 and the gluing roller 62 so as to face the lower surface opening 63 of the tank 60,
The adhesive A in the tank 60 is adhered to the gluing portion 61 of the gluing roller 62 via the relay roller 64, and is glued to each of the front and back folding flaps 1A and 1B by rotation of the gluing roller 62. The gluing roller 62 is attached via an air cylinder 65. When the bottom folding drum 10 does not have the paper cylinder 1 due to a paper jam or the like, the air cylinder 65 is driven to move the gluing roller 62 upward. Adhesion of glue to the bottom folding drum 10 is prevented. In the drawing, reference numeral 66 denotes a tray.

As shown in FIGS. 7 to 10, the bottom folding drum 10 is constituted by an assembly of a plurality of divided drums 72 fixed at appropriate intervals to a mounting cylinder 71 fixed to a rotating shaft 70. A groove 10A is provided between each of the divided drums 72. A catching claw 73 for holding the front end of the back folding flap 1B of the paper cylinder 1 and a holding claw 74 for engaging the front and rear of the fold line 2 of the back folding flap 1B are alternately arranged. Are formed. The catch claw 73
As shown in FIG. 7, is located at the center of the groove 10A, and its tip extends from the groove 10A to the outside of the outer circumference of the divided drum 72. Hold the folding flap 1B. On the other hand, holding claws 74
Are fixed claw 75 fixed to the end of groove 10A and this fixed claw
A movable claw 75A is provided in the groove 10A so as to face the opening 75. The opening and closing of the movable claw 75A clamps the front and rear of the fold line 2 of the back side flap 1B. Further, the rotating shaft 70
As shown in FIGS. 8 and 10, mounting brackets 76 and 76A of the catching claws 73 and the holding claws 74 are integrally mounted and fixed to the mounting cylinder 71 by mounting bolts 76B. The catching claw 73 and the holding claw 74 are integrally fixed to shafts 77, 77A rotatably supported by the shaft 76A.
Rotating rollers 81, 81A are provided at one end of the shafts 77, 77A of the catching claws 73 and the holding claws 74 via mounting arms 78, 78A. And rolls along a cam surface 80 fixed to the body frame 79. Further, clamps 82, 82A are integrally fixed to the shafts 77, 77A.
L is attached to the mounting brackets 76 and 76A in opposition to 82 and 82A.
The fixing brackets 83 and 83A in the shape of a letter are fixed.
Between the roller 83A and the clamps 82, 82A.
Springs 84, 84 for urging 81A to press against cam surface 80
Rods 85, 85A each having A are provided. The projections (not shown) formed on the cam surface 80 form the catching claws 73.
When the rotating rollers 81 and 81A of the holding claws 74 ride on, the catching claws 73 and the holding claws 74 are opened and closed via the rotating rollers 81 and 81A, the clamps 82 and 82A, and the shafts 77 and 77A. .

Further, on both sides of the bottom folding drum 10, FIG.
As shown in FIG. 13 to FIG. 13, a pair of opening / closing claws 90, 90A that engage the front and rear of the fold line 2 of the front side folding flap 1A are assembled. The opening and closing claws 90, 90A are both mounting brackets.
The mounting brackets 91 and 91A are rotatably mounted on a shaft 92, and one of the opening and closing claws is provided by a spring 93 provided between the mounting brackets 91 and 91A.
90A is urged against the other opening / closing claw 90 side. Further, a shaft 94 is integrally fixed to an end portion of the one mounting bracket 91, and the shaft 94 is attached to the mounting cylinder 91.
It is slidably guided by a support bracket 94A fixed to 71 and a bottom folding drum 10. Further, a pressing lever 95 for rotating the opening / closing claws 90 and 90A toward the bottom folding drum 10 is integrally assembled and fixed to the shaft 94, and the main body frame 79 corresponding to the shaft 94 is fixed. A first cam 96 contacting with the outer end surface of the shaft 94 is fixed on the outer side of both sides of the bottom folding drum 10, and the upper portion of the first cam 96 contacts the tip of the push-down lever 95. The second cam 97 is fixed. Further, a third cam 99 on which a rotating roller 98 provided on a mounting bracket 91A of the opening / closing claw 90A rides is fixed inside each of the cams 96 and 97. The shaft 94 is pressed against the first cam 96 by a spring 93A disposed in a concave portion 94A formed on the other end side, and the mounting bracket 91 for mounting the fixed side opening / closing claw 90 and the supporting bracket 91 are provided. The spring 93B bridged between the brackets 94A (FIG. 13)
The push-down lever 95 is pressed against the second cam 97.

As shown in FIG. 14, a rotating shaft 101 having two flat pushing blades 100, 100A is horizontally provided in front of the bottom folding drum 10, and the rotating shaft 101 rotates. Then, the pushing blades 100, 100A are pressed along the folding lines 2 of the folding flaps 1A, 1B of the front and back of the paper cylinder 1 conveyed by the bottom folding drum 10, and the folding line 2 is opened. The holding claws 74 and the opening / closing claws 90, 90A are guided. And the catching claw that was gripping the back side flap 1B
After the 73 is opened, the holding claws 74 and the opening / closing claws 90, 90A are closed so that the front and back folded flaps 1A, 1B which are developed in a plane are folded. Then, in this way, each of the front and back folded flaps 1
A and 1B are folded so as to be folded inward by the bottom folding device F.

As shown in FIG. 15, a bottom folding device F for folding the front and back folding flaps 1A and 1B is provided with a pair of left and right chains 105 that are bridged over a sprocket 105A in front of the bottom folding drum 10.
And a bottom folding plate 107 provided with a small gap from the peripheral surface of the bottom folding drum 10. The front folding flap 1A is moved by the bottom folding rod 106 to the bottom folding plate 10.
7, the back side folding flaps 1B are folded inward. That is, the paper tube 1 conveyed by the bottom folding drum 10 is first rotated by the rotation of the bottom folding drum 10 to rotate the bottom folding rod 106 attached to the chain 105 to rotate the front folding flap. After hitting 1A and folding inward, the bottom folding drum 10
With this rotation, the back folding flap 1B in the upright state is folded inward by passing through the gap between the bottom folding plate 107 and the bottom folding drum 10, and folded inward so as to be folded on the front folding flap 1A. Then, with the folding flaps 1A and 1B being folded, the paper cylinder 1 is sandwiched between the bottom folding drum 10 and the endless belt 110A, and the folding flaps 1A and 1B are glued together. , And bottom folding drum
After the paper bag 4 is conveyed to the rotary driving drum 108 by the endless belt 110 and the endless belt 110, the pressing device (not shown) in the final process is carried out by the rotary conveying drum 108 and the other endless belt 110A wound around the rotary conveying drum 108. The folding flaps 1A and 1B are pressed to form a square bottom 4A of the paper bag 4.

The operation of the present invention configured as described above will be described.

First, a paper cylinder 1 whose both sides are folded into a V-shape by a folding device (not shown) is conveyed to a pair of upper and lower press rollers 15 by feed pawls 14 attached to a conveyor chain 13, and the press rollers 15 1 are pressed against both sides, and the paper cylinder 1 is folded flat into a folding crease device B1.
Conveyed to. Paper cylinder 1 transported from press roller 15
Of the blade 35
To the back of the paper cylinder 1 near the mouth of the bag.
Engrave 36. Although the fold 36 at the bottom of the bag is not shown, when the handle is attached to the completed paper bag in a later process, the fold becomes a habit to fold the periphery of the bag inside in order to reinforce the bag mouth. Then, the respective rotary shafts 22 and 24 are rotated to convey the paper cylinder 1 to the creasing device B for bottom folding in the next step. Here, similarly to the above-described folding crease device B1, the vertical rotating shafts 22, 24 are used.
Is rotated and the blades 20 and 21 with the creases are pressed against the bag bottom, which is on the rear side in the transport direction of the paper cylinder 1, so that two parallel fold lines 2 and 3 are formed at the time of bottom folding. Carve a line. At this time, the first creased blade 20 on the front side in the transport direction is provided in the concave groove 28 of the cylindrical roller 23 through the paper cylinder 1 and bites into the rubber material 29, so that the folding flaps 1 </ b> A , 1B
The fold line 2 is engraved. On the other hand, the second creased blade 21 on the rear side in the transport direction abuts against the hard cylindrical roller 23 via the paper cylinder 1 and folds the front side folding flap 1A only on the surface paper of the paper cylinder 1 so that the folded line 3 Is engraved. After this,
The paper cylinder 1 containing the fold line 2 and the folding line 3 is transferred to the bottom opening device C by the rotation of each of the rotary shafts 22 and 24, and the suction pad 43 suctions the front end side of the front surface paper of the paper cylinder 1 to form a suction pad. The bag bottom of the paper cylinder 1 is opened along the rotation locus of 43, and at the same time, the catch claw 73 provided on the bottom folding drum 10 disposed close to the bottom opening device C.
To hold the front end of the back paper side of the paper cylinder 1 with the opened bag bottom, that is, the back side folding flap 1B. On the other hand, each open / close claw 90, 90A
The shaft 94 fixed to the mounting bracket 91 of the opening / closing claw 90 until the paper tube 1 is clamped by the catching claw 73 is firstly moved by the spring 93A.
The rotating rollers 98 provided on the mounting bracket 91A of the movable opening / closing claw 90A are located on the outer sides on both sides of the bottom folding drum 10 in contact with the cam 96. Riding on cam 99, mounting brackets 91, 91A
The opening direction by the biasing force of the spring 93 between
0, 90A is kept open. At substantially the same time when the paper cylinder 1 is clamped by the catching claws 73, the shaft 94 is pushed inward by the protruding portion (not shown) of the first cam 96, and the opening and closing claws 90, 90A are pressed against the spring 93A. Is the inside, that is, the figure
Paper cylinder 1 moved in the direction of arrow a 12 and held down by catching claws 73
Overhang. On the other hand, the push-down lever 95 fixed to the shaft 94 is pressed against the second cam 97 by the spring 93B. The push-down lever 95 falls into the depressed portion 97A of the second cam 97, and the shaft 94 rotates clockwise as shown in FIG. 13, and with the rotation of the shaft 94, the opening / closing claws 90, 90A face downward. It rotates and comes into contact with the surface paper of the paper cylinder 1. At this time, in the opening / closing claws 90, 90A, the fixed opening / closing claw 90 is located in front of the fold line 2 of the front folding flap 1A, and the movable opening / closing claw 90A is located behind the fold line 2. And
The bag bottom of the paper cylinder 1 is opened by rotating the upper rotation shaft 40 and the bottom folding drum 10 in mutually opposite directions. In this way, the bottom of the paper cylinder 1 with the opened bottom of the bag is guided between the left and right guide plates 50 and the bottom folding drum 10 by the rotation of the bottom folding drum 10 so that the bottom of the bag forms the flap folding device D. In rare cases, only the front side folding flap 1A is folded back to the front paper side of the paper cylinder 1, and each of the front and back folding flaps 1A and 1B of the paper cylinder 1 is developed flatly along the outer periphery of the bottom folding drum 10. At this time, each opening claw 9
Reference numerals 0 and 90A are disposed between the front surface paper of the paper cylinder 1 and the front side folding flap 1A. The paper cylinder 1 is conveyed by the rotation of the bottom folding drum 10, and is glued to each of the front and back folding flaps 1 </ b> A and 1 </ b> B by the gluing roller 62 during this conveyance. After this gluing step, the rotating shaft 101 rotates, and the pushing blade 10
0 and 100 A are the fold lines 2 of the front and back flaps 1A and 1B
And the fold line 2 is guided between the holding claws 74 and the opening / closing claws 90, 90A. By closing the holding claws 74 and the opening / closing claws 90, 90A, the front and back folded flaps 1A, 1B which are developed are sandwiched so as to stand. Then, the paper cylinder 1 in which the front and back folding flaps 1A and 1B are raised.
First, the front side folding flap 1A is folded inward by the bottom folding rod 106 by the rotation of the chain 105, and then the bottom folding drum
10 transports the back folding flap 1B to the bottom folding drum 10
And the bottom folding plate 107, the back side folding flap 1B is folded on the front side folding flap 1A. After that, the endless belt stretched over a plurality of guide rollers 109
By sandwiching the paper cylinder 1 between the endless belt 110 and the endless belt 110, the front and back folding flaps 1A and 1B are overlapped,
The paper bag 4 is conveyed by a rotary drive drum 93 and an endless belt 110A to a pressing device (not shown) in the next step, and finally, the folding flaps 1A, 1B on the front and back sides are pressed to remove the square bottom 4A of the paper bag 4. Molding.

As described above, in the present embodiment, the folding line 2 of each of the folding flaps 1A and 1B for folding the square bottom portion 4A is formed by connecting the first creased blade 20 to the cylindrical roller as in the prior art.
The paper cylinder 1 is made to bite into the rubber material 29 provided in the concave groove 28 of 23.
The fold lines 2 of the fold flaps 1A and 1B are engraved on the front and back sides of the fold flaps 1A and 1B. A folding line 3 necessary for turning over the folding flap 1A is engraved only on the front surface paper of the paper cylinder 1, and a folding line 3 unnecessary for folding the front folding flap 1A is formed on the back side of the paper cylinder 1. As shown in FIG. 16, no streaky trace is left on one side of the completed paper bag 4 as shown in FIG. Further, as an effect on the embodiment, in the bottom folding process, the opening / closing claws 90, 90A are arranged between the front side folding flap 1A turned upside down and the surface paper of the paper cylinder 1, and the opening / closing claws 90, 90A are opened and closed. Since the front side flap 1A is folded around the fold line 2 of the front side flap 1A, the paper bag 4 can be formed without leaving any bite marks on the paper cylinder 1 and having excellent external design.

FIGS. 17 and 18 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In the first embodiment, the case where the folded line 3 is engraved over the entire width of the paper cylinder 1 by the flat plate-shaped second creased blade 21 has been described. A notch 21A is formed in the central portion of the second creased blade 21 into which the sheet 3 is to be inserted. That is, since the paper cylinder 1 is formed by folding both sides into a V-shape in the pre-step of bottom folding, the paper cylinder 1 is formed thicker at both sides overlapping in a V-shape than at the center. In the embodiment, the notch 21 is formed at the center of the second creased blade 21.
By forming A, as shown in FIG. 17, the creased blades 21 are pressed against only the both sides of the thickly formed paper cylinder 1 which overlaps in a V-shape to form the folded line 3. That is, in the present embodiment, the folding line 3 is engraved only on the left and right sides of the paper cylinder 1, but the folding line 3 is simply formed by the front folding flap 1
Since the folding habit is caused when A is folded, if the folding lines 3 are formed even on the left and right sides of the paper cylinder 1, the flap folding device D can accurately fold the front folding flap 1A from the folding line 3. As described above, in the present embodiment, the notched portion 21A of the second creased blade 21 intensively presses the creased blade 21 on the left and right sides of the paper cylinder 1 having a greater thickness than the central portion, so that the front side folding flap is used. In folding back 1A, the folding lines 3 can be accurately formed on the left and right sides of the most important paper cylinder 1.

FIG. 19 shows a third embodiment of the present invention. The same parts as those of the above embodiments are denoted by the same reference numerals, and description thereof will be omitted.

In the second embodiment, a second creased blade is provided.
Although the example in which the intermittent fold line 3 is carved on both the left and right sides of the surface paper of the paper cylinder 1 by the notch portion 21A formed in the center portion of 21 is shown, in this example, the second creased blade 21 is provided. It is divided into left and right, and formed to have a length substantially corresponding to the V-shaped folded portion folded on both sides of the paper cylinder 1. In this way, the second creased blades 21 divided into left and right are respectively attached to the blade holder. twenty five
It can be adjusted up and down. That is, in the present embodiment, a long hole 26A through which the fixing screw 26 is inserted is formed in the second creased blade 21 divided into right and left, and the screw 26 is loosened and divided into right and left within the range of the long hole 26A. Second scoring blade
By assembling the upper part 21 so as to be movable up and down, the divided second creased blades 21 can be attached to the blade holder 25 with different heights.
That is, the paper cylinder 1 forms a margin for gluing to one side edge, and one side edge of the paper cylinder 1 on which the margin is formed is thicker than the other side edge. Then, the second scoring blade on the left side of the drawing pressed against one side edge forming the glue allowance
By assembling the blade 21 with the blade holder 25 so as to be lower than the second creasing blade 21 on the right side of the drawing by the amount of glue, the left and right split second creasing blades 21 are evenly distributed on both sides of the paper cylinder 1. Can be pressed.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.
For example, the structure of the gluing device, the bottom opening device, the transport device, and the like, the driving means thereof, and the opening / closing means of the holding claws and the opening / closing claws are not limited to cams, but may be appropriately set such as cylinder devices.
Further, although an example in which the scoring blade is pressed against the paper cylinder by rotation has been described, the scoring blade may be moved up and down and pressed against the paper cylinder. Further, in the above-described embodiment, an example is shown in which one sheet cut to a predetermined size before the bottom folding is folded to form a paper cylinder. However, the present invention is not limited to this, and a continuous tubular paper cylinder is cut to a predetermined size. To form a paper cylinder. In this case, a roll for winding the tube-shaped paper cylinder may be provided, and a cutter device for cutting the tube-shaped paper cylinder drawn out of the roll into a predetermined size may be arranged in front of the creasing device. Further, the material and shape of the rubber material to be cut into the first creased blade and the mounting structure thereof may be set as appropriate, and the shape of the cylindrical roller for mounting the rubber material may be set as appropriate.

[0030]

According to the first aspect of the present invention, a paper cylinder having front and rear openings is formed by gluing the side edges, and the paper cylinder is transported and transported and supplied to a bottom folding process. A first creased blade for engraving a fold line of the folding flap near the bottom opening of the paper cylinder, and a fold line for folding the folding flap on the front side of the paper cylinder inside out parallel to the fold line. In a creasing device for a square bottom bag provided with a second creasing blade to be provided, a blade holder for assembling the first and second creasing blades is provided, and the paper cylinder is interposed below the blade holder. A hard receiving portion for abutting the first and second creased blades, a recessed groove corresponding to the first creased blade is formed in this receiving portion, and flexibility for mounting in the recessed groove is provided. The paper cylinder is sandwiched between the rubber material and the first creased blade, and The fold line of the folding flap is engraved at the same time, and the paper cylinder is sandwiched between the receiving portion and the second scoring blade, and the folded line is engraved only on the surface side of the paper cylinder, so that the bottom fold is formed. At this time, it is possible to provide a corner bottom bag creasing device that can eliminate unnecessary traces of the folded line.

According to the second aspect of the present invention, the second creased blade is divided into right and left, and the left and right divided second creased blades are respectively assembled to the blade holder so as to be adjustable in height. Accordingly, the second creased blade divided into the left and right can be uniformly pressed against both sides of the paper cylinder.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of the creasing device as viewed from a side.

FIG. 3 is a cross-sectional view of the vicinity of the creasing device viewed from the front.

FIG. 4 is an explanatory view showing a fold of the flap, and FIG.
Is a front view before the fold is made, and (B) is a front view after the fold is made.

FIG. 5 is a partially cutaway side view near the bottom opening device.

FIG. 6 is a sectional view showing the vicinity of the first gluing device.

FIG. 7 is a side view of the vicinity of the capturing claw.

FIG. 8 is a cross-sectional view of the vicinity of the capturing claw.

FIG. 9 is a side view of the vicinity of the holding claw.

FIG. 10 is a cross-sectional view of the vicinity of the holding claw.

FIG. 11 is a perspective view of the bottom folding drum showing the bottom folding state.

FIG. 12 is a sectional view showing the vicinity of the opening / closing claw.

FIG. 13 is a side view of the vicinity of the opening / closing claw.

FIG. 14 is a side view of the vicinity of the pushing blade.

FIG. 15 is a partially cutaway side view of the bottom folding device showing a folded state of the flap.

FIG. 16 is a perspective view of the completed paper bag.

FIG. 17 is a sectional view showing the vicinity of a creasing device according to a second embodiment of the present invention.

FIG. 18 is a perspective view schematically showing the creasing device.

FIG. 19 is a sectional view showing the vicinity of a creasing device according to a third embodiment of the present invention.

FIGS. 20A and 20B are explanatory views showing a folded state of a conventional flap, in which FIG. 20A is a perspective view before being folded, FIG. 20B is a perspective view showing an unfolded state of the flap, and FIG. It is.

FIG. 21 is a sectional view of the creasing device.

FIG. 22 is a perspective view of the paper bag.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper cylinder 1A Front side folding flap 1B Back side folding flap 2 Folding line 3 Folding line 8 Paper bag 20 First creasing plate 21 Second creasing plate 25 Plate holder 23 Cylindrical roller (receiving part) 26 Rubber material 28 Groove C creasing device

Claims (2)

(57) [Claims] 1. A paper cylinder having front and rear openings formed by gluing side edges thereof, and conveying the paper cylinder to be conveyed and supplied to a bottom folding step, and a folding flap near a bottom opening of the paper cylinder during the conveyance. A first creased blade for engraving a fold line, and a second creased blade for engraving a fold line for folding back a folding flap on the front side of the paper cylinder in parallel with the fold line. In the creasing device for a square-bottom bag provided with a blade, a blade holder for assembling the first and second creasing blades is provided, and the first and second creasing lines are provided below the blade holder via the paper cylinder. A hard receiving portion for abutting the blade is provided, and a concave groove corresponding to the first creasing blade is formed in the receiving portion, and a flexible rubber material to be mounted in the concave groove and the first rubber member.
The paper cylinder is sandwiched by the creased blades and the fold lines of the folding flaps are engraved on the front and back of the paper cylinder, and the paper cylinder is sandwiched by the receiving portion and the second scoring blade. A creasing device for a square-bottom bag, wherein a folded line is engraved only on the front side of the tube. 2. The apparatus according to claim 1, wherein the second creased blade is divided into right and left, and the divided second creased blades are respectively assembled to the blade holder so as to be adjustable in height. An apparatus for creasing a square bottom bag as described in the above.