JP7632255B2 - Crease processing device, cardboard box, and crease processing method - Google Patents

Description

This case relates to a device for forming creases in cardboard sheets to be assembled into boxes, a cardboard box formed with creases by this device, and a method for forming creases in the cardboard sheets.

Cardboard boxes are sometimes wrapped with bands to prevent unintentional opening and to improve transportability. A problem with cardboard boxes wrapped with bands is that the corners, where stress is concentrated due to the tightening force of the bands, are prone to tearing and crushing. In response to this, Patent Document 1 proposes a technique in which lines (creases) that form a leaf-shaped outline are provided at the corners of the cardboard box, and the parts surrounded by these lines are recessed inward into the cardboard box. With the technique of Patent Document 1, the corners of the cardboard box are made obtuse, which can prevent damage to the corners caused by banding.

Japanese Utility Model Application Publication No. 59-38224

The above-mentioned creases are formed by pressing a crease blade that forms the leaf-shaped outline against the cardboard sheets that are to be assembled into a cardboard box. When processing creases that form closed shapes like this, the crease blade is more likely to bite into the cardboard sheet and create large localized tensile forces, compared to, for example, processing straight lines. This poses the problem that the cardboard sheet is more likely to tear.

This invention was conceived in consideration of the above problems, and one of its objectives is to prevent the cardboard sheet from tearing when the scoring lines are processed. However, this objective is not the only objective. Another objective of this invention is to achieve actions and effects that cannot be obtained with conventional technology, which are derived from the configurations shown in the "Mode for carrying out the invention" described below.

The crease processing device in this case is a crease processing device that processes creases in cardboard sheets to be assembled into a box, so as to form recesses in a leaf shape with both sharp ends of the leaf shape located at the corners of the box, and is characterized by having a crease blade that protrudes from a base along the outline of the leaf shape and forms the crease by being pressed against the cardboard sheet, an outer elastic body made of an elastic material softer than the crease blade and attached to the outside of the crease blade on the base, and an inner elastic body made of an elastic material softer than the crease blade and attached to the inside of the crease blade on the base.

The cardboard box in question is characterized in that the creases are made using the crease making device described above.

The present creasing method is a creasing method for forming leaf-shaped recesses in cardboard sheets to be assembled into a box, with both sharp ends of the leaf shape located at the corners of the box, and is characterized by comprising a creasing step of pressing a creasing blade that forms the outline of the leaf shape against the cardboard sheet to form the creasing lines, an outer pressing step of pressing an outer elastic body made of an elastic material softer than the creasing blade against the outside of the portion of the cardboard sheet against which the creasing blade is pressed, during the creasing step, and an inner pressing step of pressing an inner elastic body made of an elastic material softer than the creasing blade against the inside of the portion of the cardboard sheet against which the creasing blade is pressed, during the creasing step.

This makes it possible to prevent the cardboard sheet from tearing when the lines are cut.

FIG. 2 is a plan view of a cardboard sheet to be assembled into a cardboard box according to one embodiment, and the cardboard box folded flat. FIG. 2 is a perspective view showing a state in which a cardboard box according to one embodiment is banded. 3 is an enlarged partial cross-sectional view of the periphery of a recess in a cardboard box according to one embodiment (a view corresponding to the view seen in the direction of the arrow A in FIG. 2 ). FIG. 1 is a block diagram showing a configuration of a box making device according to an embodiment; FIG. 2 is a side view of a rotating drum to which the scoring device according to the embodiment is applied. FIG. 13 is a side view of a flat plate to which a crease processing device according to one modified example is applied. FIG. 2 is a plan view of the scoring device according to the embodiment. FIG. 8 is a side view of a main part of the scoring device according to the embodiment (as viewed in the direction of the arrow B in FIG. 7 ). FIG. 8 is a cross-sectional view of a main part of the scoring device according to the embodiment (a cross-sectional view taken along the CC arrow in FIG. 7). 1 is a chart showing a crease processing method according to an embodiment. 13 is a chart showing a method for processing lines according to one modified example.

The following describes the form for implementing the present invention. The embodiments described below are merely examples, and are not intended to exclude the application of various modifications or techniques not explicitly stated herein. The configurations of the following embodiments can be modified in various ways without departing from the spirit of the invention. Furthermore, they can be selected or combined as necessary.

[1. Cardboard Box]
As shown in Fig. 1, a cardboard box 2 according to this embodiment is formed from a single cardboard sheet 1. Fig. 1 illustrates a cardboard box 2 folded flat, and hereinafter, the cardboard box 2 folded flat in this manner is also referred to as a "flat box 2A."
First, a description will be given of the configuration of the cardboard sheet 1 to be assembled into the cardboard box 2. In the following description, it is assumed that the cardboard sheet 1 is unfolded in a plane, and two directions perpendicular to each other in the plane in which the cardboard sheet 1 extends are defined as a horizontal direction Dx and a vertical direction Dy. In the cardboard sheet 1 of this embodiment, a hollow portion formed by a corrugated core extends along the vertical direction Dy.

The cardboard sheet 1 comprises two long side panels 11 and two short side panels 12 arranged alternately in the horizontal direction Dx, outer flaps 13 connected to both sides of each long side panel 11 in the vertical direction Dy, and inner flaps 14 connected to both sides of each short side panel 12 in the vertical direction Dy. The long side panels 11 and the outer flaps 13 are formed to have a larger dimension in the horizontal direction Dx than the short side panels 12 and the inner flaps 14. On the other hand, the dimensions in the vertical direction Dy of the long side panels 11 and the short side panels 12 are the same. The dimensions in the vertical direction Dy of the outer flaps 13 and the inner flaps 14 are also the same.

Here, an example is shown of a cardboard sheet 1 in which one long side panel 11, one short side panel 12, the other long side panel 11, and the other short side panel 12 are arranged in this order from one side to the other in the horizontal direction Dx (from left to right in Fig. 1). A bonding piece 15 is connected to one long side panel 11 for connecting the one long side panel 11 to the other short side panel 12 when the cardboard sheet 1 is assembled into a cardboard box 2. The bonding piece 15 protrudes from one long side panel 11 to one side in the horizontal direction Dx (in the direction away from one short side panel 12).

Linear horizontal creases (corrugator creases) 16 extending in the horizontal direction Dx are provided at the boundaries between the long side panels 11 and each outer flap 13, and between the short side panels 12 and each inner flap 14. Linear vertical creases 17 extending in the vertical direction Dy are provided at the boundaries between the long side panels 11 and the short side panels 12 adjacent to each other in the horizontal direction Dx, and at the boundaries between one long side panel 11 and the bonding piece 15. Both the horizontal creases 16 and the vertical creases 17 are creases (grooves) processed into the cardboard sheet 1, and guide the folding when the cardboard sheet 1 is assembled into the cardboard box 2. The horizontal creases 16 and the vertical creases 17 are arranged at the corners of the cardboard box 2.

The cardboard sheet 1 is machined with creases 3 that form a leaf-shaped outline. The "leaf-shaped" here refers to an ellipse with both ends on the major axis sharpened. Hereinafter, these creases 3 are also referred to as "corner creases 3." The corner creases 3 in this embodiment are ellipse shapes that are longer in the horizontal direction Dx than in the vertical direction Dy, with both ends sharpened in the horizontal direction Dx. The corner creases 3 are closed shapes because they form a leaf-shaped outline. For example, the corner creases 3 are formed by extending two arcs near the minor axis of the ellipse while maintaining their respective radii of curvature, and the points of intersection are the sharpened ends (portions with both ends sharpened on the major axis of the ellipse).

The sharp ends of the corner crease 3 are located on the horizontal crease 16 that will become the corners of the cardboard box 2. The corner crease 3 is a groove for forming a leaf-shaped depression 4 (see FIG. 2) at the corner of the cardboard box 2. In this embodiment, the corner crease 3 is formed symmetrically with respect to the horizontal crease 16 on which it overlaps. The horizontal crease 16, vertical crease 17, and corner crease 3 are all formed on the same surface (back surface) of the cardboard sheet 1.

The cardboard sheet 1 has two corner creases 3 formed thereon, which overlap the horizontal creases 16 extending along the boundary between the long side panel 11 and one (lower in FIG. 1) of the outer flaps 13. Each corner crease 3 is disposed at the center of the horizontal crease 16 in the horizontal direction Dx where the corner crease 3 overlaps. The number and arrangement of the corner creases 3 are not limited to those illustrated here. For example, the corner creases 3 may be disposed so as to overlap each of the horizontal creases 16 extending along the boundary between the long side panel 11 and each of the outer flaps 13. Alternatively, two corner creases 3 may be disposed at intervals in the horizontal direction Dx for one horizontal crease 16. The corner creases 3 can be effective even if they are provided on one of the two horizontal creases 16 spaced apart from each other in the vertical direction Dy (up and down in FIG. 1) as in this embodiment, but it is more preferable that they are provided on each of the two horizontal creases 16 (the horizontal creases 16 extending along the boundaries between the long side panel 11 and the outer flaps 13 on both sides).

The corrugated cardboard sheet 1 becomes a flat box 2A when one long side panel 11 and the other short side panel 12 are connected by a bonding piece 15. The flat box 2A is folded along each of the horizontal lines 16 and vertical lines 17 to be assembled into a three-dimensional corrugated cardboard box 2 as shown in FIG.
As shown in Fig. 2, the cardboard box 2 of this embodiment is a so-called Type A (0201 format) box, and has a rectangular parallelepiped shape. The configuration of the cardboard box 2 will be described below assuming that the cardboard box 2 is placed on a horizontal surface. The cardboard box 2 is assembled so that the processed surfaces of the creases 16, 17, and 3 in the cardboard sheet 1 face inward (inner surface). In other words, all of the creases 16, 17, and 3 are processed for inward folding.

In the cardboard box 2, each long side panel 11 is arranged along the height direction (vertical direction) D1 and the length direction (horizontal direction) D2, and each short side panel 12 is arranged along the height direction D1 and the width direction (horizontal direction) D3. In addition, both the outer flaps 13 and the inner flaps 14 are arranged along the length direction D2 and the width direction D3. The long side panels 11 and the short side panels 12 form the sides of the cardboard box 2, and the outer flaps 13 and the inner flaps 14 form the top and bottom surfaces of the cardboard box 2. In the cardboard box 2, the outer flaps 13 are arranged outside the inner flaps 14, and the inner flaps 14 are covered and hidden by the outer flaps 13.

2 and 3 , the cardboard box 2 has a depression 4 formed by folding the cardboard sheet 1 at a corner line 3. The pointed ends of the leaf-shaped depression 4 are located at the corners of the cardboard box 2. In this embodiment, the depression 4 has both pointed ends located on the horizontal line 16.
The recess 4 has a function of partially chamfering the right-angled corners of the cardboard box 2. In other words, the right-angled corners of the cardboard box 2 are partially made obtuse by the recess 4. The recess 4 in this embodiment is formed in the corner between the long side panel 11 and the outer flap 13 forming the lower surface. In other words, the cardboard box 2 is used in a position where the corner with the recess 4 is located on the lower side.

A strip-shaped band 5 is wrapped around the cardboard box 2. The band 5 is a so-called PP band made of plastic. The band 5 is arranged to fasten the long side panel 11 and the outer flap 13 from the outside, preventing unintentional opening of the outer flap 13. Note that while FIG. 2 shows an example of one cardboard box 2 wrapped with the band 5, multiple cardboard boxes 2 may be integrated together by wrapping the band 5 around multiple cardboard boxes 2.

The band 5 is fixed in contact with the recess 4 of the cardboard box 2. In this way, the band 5 is positioned so that it fits into the recess 4, preventing it from shifting out of position or falling out of the cardboard box 2. In addition, the fastening force of the band 5 acts on the recess 4 of the cardboard box 2, but at the corners that are made obtuse by the recess 4, stress concentration due to the fastening force of the band 5 is mitigated. Therefore, damage to the corners of the cardboard box 2 caused by the fastening force of the band 5 is prevented.

[2. Box making equipment]
[2-1. Overall configuration]
The cardboard box 2 according to this embodiment is manufactured by a box making device 20 shown in Fig. 4. The box making device 20 is a so-called flexo folder-gluer that performs processes from printing to forming the cardboard box 2 in a continuous process. In the box making device 20, a flat box 2A is formed from a cardboard sheet 1. Hereinafter, upstream and downstream are defined based on the conveying direction of the cardboard sheet 1 in the box making device 20. Note that Fig. 4 shows both the cardboard sheet 1 and the flat box 2 as a bundle.

The box making device 20 is provided with, in order from the upstream, a paper feed section 21, a printing section 22, a scoring and grooving section 23, a die cutting section 24, a folder gluer section 25, and a counter ejector section 26. The paper feed section 21 is supplied with a sheet of cardboard sheet 1 that has been pre-cut into a rectangular shape of a specified size. The above-mentioned horizontal lines 16 have been pre-processed into this cardboard sheet 1.

The cardboard sheet 1 sent out from the paper feed section 21 is printed with desired characters and patterns on its surface in the printing section 22. Next, the cardboard sheet 1 is grooved and scored by a slotter device and a creaser device provided in the scoring and grooving section 23. Next, in the die-cutting section 24, the cardboard sheet 1 is punched and cut.
In the folder-gluer section 25, the corrugated cardboard sheet 1 is folded and glued, thereby forming flat boxes 2A. The flat boxes 2A are then stacked while being counted in the counter-ejector section 26, and are discharged as a batch of a predetermined number.

[2-2. Main part configuration]
As shown in FIG. 5, the crease processing device 10 according to this embodiment processes a corner crease 3 on a cardboard sheet 1. The crease processing device 10 is generally provided in a die-cutting section 24 of a box making device 20. In this embodiment, the crease processing device 10 mounted on the peripheral surface of a cylindrical rotating drum 27 in the die-cutting section 24 is illustrated. Next to the rotating drum 27 (on the upper side in FIG. 5), an impression drum 28 having a rotation axis A2 parallel to the rotation axis A1 of the rotating drum 27 is disposed. The crease processing device 10 processes a corner crease 3 on the moving cardboard sheet 1 when the cardboard sheet 1 passes through the gap between the rotating drum 27 and the impression drum 28. In the crease processing device 10, the cardboard sheet 1 is transported along the vertical direction Dy.

In addition, the crease processing device 10 may be applied to a flat platen 29 that moves up and down as shown in FIG. 6, instead of the above-mentioned rotating drum 27. In this case, the crease processing device 10 is attached to the underside of the flat platen 29, and processes the corner crease 3 on the stationary cardboard sheet 1 when the cardboard sheet 1 is sandwiched between the flat platen 29 and the table 30 arranged below it.

As shown in FIG. 7, the crease processing device 10 includes a crease blade 6 protruding from a base 9, and an outer elastic body 7 and an inner elastic body 8 formed of an elastic material softer than the crease blade 6. In FIG. 7 and FIG. 8 described later, the outer elastic body 7 is shown with light dots, and the inner elastic body 8 is shown with dark dots. The base 9 is, for example, a mold in which the crease blade 6 is embedded and fixed. The base 9 is fixed to the circumferential surface of the rotating drum 27 by a fixing device or adhesive (not shown). Note that while FIG. 7 shows a flat base 9, the base 9 formed of a rigid body (e.g., a wooden mold) is curved in advance to fit the circumferential surface of the rotating drum 27.

The crease blade 6 forms a leaf-shaped outline corresponding to the square crease 3 and the recess 4. In a plan view of the base 9, the crease blade 6 defines the leaf-shaped area corresponding to the recess 4. That is, the crease blade 6 forms a closed shape similar to the square crease 3. The crease blade 6 forms the square crease 3 on the cardboard sheet 1 by pressing it against the cardboard sheet 1. The crease blade 6 is made of, for example, metal. Hereinafter, the portions of the crease blade 6 that correspond to both sharp ends of the leaf-shaped area are also referred to as "blade end 6a". The blade end 6a is a portion that forms the outline of both sharp ends of the leaf-shaped area. The blade end 6a is pressed against the horizontal crease 16 of the cardboard sheet 1 that will become the corner of the cardboard box 2.

As shown in FIG. 8, the crease blade 6 of this embodiment is formed such that the protruding dimension L1 of the blade end 6a from the base 9 is smaller than the protruding dimension of the portion other than the blade end 6a from the base 9. In other words, the protruding dimension L2 of the blade end 6a of the crease blade 6 is the minimum protruding dimension. In this embodiment, a crease blade 6 is illustrated in which the protruding dimension from the base 9 in a certain region 6b including the blade end 6a is gradually reduced as it approaches the blade end 6a. In other words, in the certain region 6b, the tip, which is the protruding end of the crease blade 6, is inclined toward the base 9 as it approaches the blade end 6a. Note that the protruding dimension L2 from the base 9 of the crease blade 6 is uniform in the portions other than the certain region 6b (L1<L2). Therefore, the protruding dimension L2 of the portion other than the certain region 6b of the crease blade 6 is the maximum protruding dimension.

Hereinafter, the side where the area surrounded by the crease blade 6 is located will be referred to as the "inner side" and the opposite side will be referred to as the "outer side" with respect to the crease blade 6 as the reference. As shown in FIG. 7, the outer elastic body 7 is attached to the outer side of the crease blade 6 on the base 9. The inner elastic body 8 is attached to the inner side of the crease blade 6 on the base 9. Both the outer elastic body 7 and the inner elastic body 8 are fixed to the surface of the base 9 on the side where the crease blade 6 protrudes. The method of fixing the outer elastic body 7 and the inner elastic body 8 to the base 9 is not particularly limited, and for example, a fixing device (not shown) or an adhesive may be used.

The outer elastic body 7 is provided so as to surround the scoring blade 6 in a plan view of the base 9. In this embodiment, the outer elastic body 7 has an outer shape that is a slightly larger version of the leaf shape defined by the scoring blade 6. The outer elastic body 7 is pressed against the area surrounding the corner score 3 (the area outside the corner score 3) in a plan view of the cardboard sheet 1.

Meanwhile, the inner elastic body 8 is provided in the area surrounded by the crease blade 6 in a plan view of the base 9. In this embodiment, an inner elastic body 8 having a shape that matches the leaf shape defined by the crease blade 6 (i.e., a shape that corresponds to the depression 4 formed in the cardboard box 2) is exemplified. The inner elastic body 8 is pressed against the area surrounded by the corner creases 3 in a plan view of the cardboard sheet 1 (the area inside the corner creases 3, which becomes the depression 4 in the cardboard box 2).

Here, a detailed description will be given of the thickness dimensions of the outer elastic body 7 and the inner elastic body 8. The thickness dimensions referred to here correspond to the protruding dimensions of the outer elastic body 7 and the inner elastic body 8 from the base 9.
As shown in Fig. 9, the outer elastic body 7 is formed such that the thickness dimension L3 of the reductive corner 7a adjacent to the blade end 6a is smaller than the thickness dimension L4 of the other part of the reductive corner 7a (L3<L4). In Fig. 9, the thickness dimension of the part of the reductive corner 7a closest to the blade end 6a is indicated by the symbol "L3". In this embodiment, the reductive corner 7a is illustrated in which the thickness dimension L3 is reduced as it approaches the blade end 6a. That is, the top surface of the reductive corner 7a (the surface that contacts the cardboard sheet 1 when processing the corner line 3) is inclined toward the base 9 as it approaches the adjacent blade end 6a. On the other hand, the thickness dimension L4 of the outer elastic body 7 other than the reductive corner 7a is uniform. Therefore, the thickness dimension L4 of the part of the outer elastic body 7 other than the reductive corner 7a is the maximum thickness dimension.

The inner elastic body 8 is formed so that the thickness dimension L5 of the minor corner portion 8a adjacent to the blade end 6a is smaller than the thickness dimension L6 of the portion other than the minor corner portion 8a (L5<L6). In FIG. 9, the thickness dimension of the portion of the minor corner portion 8a closest to the blade end 6a is indicated by the symbol "L5". In this embodiment, the minor corner portion 8a in which the thickness dimension L5 is reduced as it approaches the blade end 6a is illustrated. That is, the top surface of the minor corner portion 8a (the surface that contacts the cardboard sheet 1 when processing the corner line 3) is inclined downward toward the base 9 as it approaches the adjacent blade end 6a. On the other hand, the thickness dimension L6 of the inner elastic body 8 other than the minor corner portion 8a is uniform. Therefore, the thickness dimension L6 of the portion other than the minor corner portion 8a is the maximum thickness dimension of the inner elastic body 8.

The thickness dimension of the inner elastic body 8 in this embodiment is set to be equal to or greater than the thickness dimension of the outer elastic body 7. In detail, the thickness dimension of the inner elastic body 8 is equal to or greater than the maximum thickness dimension L4 of the outer elastic body 7 throughout the entire inner elastic body 8 (L4≦L5<L6), and the maximum thickness dimension L6 of the inner elastic body 8 is greater than the maximum thickness dimension L4 of the outer elastic body 7. In other words, the inner elastic body 8 is formed thicker than the outer elastic body 7 in all or most of its part (excluding a part of the minor angle portion 8a).

In this embodiment, the maximum thickness dimension L6 of the inner elastic body 8 is set to be larger than the maximum protruding dimension L2 of the crease blade 6 (L2<L6). Therefore, the inner elastic body 8 protrudes from the base 9 more than the crease blade 6. Furthermore, the thickness dimensions L3, L4 of the outer elastic body 7 are set to be smaller than the protruding dimensions L1, L2 of the crease blade 6 (L3<L4<L1<L2). In other words, the outer elastic body 7 is set to have a smaller thickness dimension throughout its entirety than the minimum protruding dimension L2 of the crease blade 6.

Although the outer elastic body 7 and the inner elastic body 8 of this embodiment have different shapes as described above, they are made of the same material and have the same physical properties. A black cellulosic sponge with a hardness of 25 degrees is suitable as a material used for the outer elastic body 7 and the inner elastic body 8. The outer elastic body 7 may be formed from a single piece of black cellulosic sponge, and the inner elastic body 8, which has a greater thickness than the outer elastic body 7, may be formed by stacking two pieces of black cellulosic sponge similar to the outer elastic body 7. In this way, by using the same material for the outer elastic body 7 and the inner elastic body 8 while varying the number of layers, the above-mentioned thickness relationship can be achieved while improving ease of manufacture.

Examples of various dimensions are shown below.
Maximum protruding dimension L2 of the crease blade 6: 9 mm
Maximum thickness dimension L4 of outer elastic body 7: 7 mm
Maximum thickness dimension L6 of the inner elastic body 8: 14 mm

3. Method
The crease processing method according to this embodiment is carried out by the above-mentioned crease processing device 10. As shown in Fig. 10, the crease processing method includes a crease forming step S1 of forming corner creases 3 by pressing a crease blade 6 against a cardboard sheet 1, an outer pressing step S2 of applying an outer elastic body 7 to the outside of the portion of the cardboard sheet 1 against which the crease blade 6 is pressed, and an inner pressing step S3 of applying an inner elastic body 8 to the inside of the portion of the cardboard sheet 1 against which the crease blade 6 is pressed.

The outer pressing process S2 and the inner pressing process S3 are carried out while the crease forming process S1 is being carried out. In other words, the three processes S1 to S3 are carried out in parallel (simultaneously) for at least a certain period of time. In this embodiment, the processing of the corner creases 3 on the cardboard sheet 1 progresses as the rotating drum 27 on which the crease processing device 10 is mounted rotates. For this reason, the outer pressing process S2 is started first, then the crease forming process S1 is started, and then the inner pressing process S3 is started. After that, the inner pressing process S3 is completed first, then the crease forming process S2 is completed, and then the outer pressing process S2 is completed.

However, the order of starting and ending the three steps S1 to S3 is not limited to this. For example, the order of starting and ending the three steps S1 to S3 may be changed depending on the relationship between the protruding dimension of the crease blade 6 and the thickness dimensions of the outer elastic body 7 and the inner elastic body 8. In addition, in the crease processing method performed by the crease processing device 10 attached to the flat plate 29, the crease blade 6, the outer elastic body 7, and the elastic body 8 are pressed against the cardboard sheet 1 in the order of the largest protruding dimension from the base 9. For this reason, as shown in FIG. 11, in the crease processing method used with the flat plate 29, the three steps S1 to S3 start in the order of the inner pressing step S3, the crease processing step S1, and the outer pressing step S2, and the three steps S1 to S3 end in the reverse order.

[4. Actions and Effects]
(1) According to the scoring device 10, the outer elastic body 7 and the inner elastic body 8 are attached to the outer and inner sides of the scoring blade 6 on the base 9, respectively, so that when the scoring blade 6 forms the corner scores 3 for the leaf-shaped depressions 4, the outer elastic body 7 and the inner elastic body 8 can be applied to the outer and inner sides of the portion of the cardboard sheet 1 against which the scoring blade 6 is pressed. As a result, the outer elastic body 7 and the inner elastic body 8 hold the cardboard sheet 1 against the tensile force generated by the scoring blade 6 biting into the cardboard sheet 1, thereby suppressing localized elongation (stress concentration) of the cardboard sheet 1. Therefore, damage to the cardboard sheet 1 can be suppressed when the corner scores 3 are processed.

In particular, when the horizontal crease 16 of the cardboard sheet 1 is a corrugator crease that is formed in advance by a slitter scorer of a corrugator during the manufacture of an A-type cardboard box 2, the corrugator crease (horizontal crease 16) is formed stronger than a normal crease formed by a flexo folder gluer. In this case, in order to more reliably form the recess 4 at the corner of the cardboard box 2, it is necessary to process the corner crease 3 deeper than the horizontal crease 16. Therefore, it is required to press the crease blade 6 against the cardboard sheet 1 with a stronger force. In contrast, according to the crease processing device 10, the cardboard sheet 1 is held down by the outer elastic body 7 and the inner elastic body 8 when the corner crease 3 is processed by the crease blade 6 as described above, so that localized elongation of the cardboard sheet 1 is suppressed. Therefore, even when the crease blade 6 is pressed against the cardboard sheet 1 with the horizontal crease 16 with a strong force, damage to the cardboard sheet 1 can be suppressed. In this way, the crease processing device 10 is particularly effective when forming corner creases 3 on A-type cardboard boxes 2.

(2) If the thickness dimension of the inner elastic body 8 is equal to or greater than the thickness dimension of the outer elastic body 7, the inside of the corner crease 3 in the cardboard sheet 1 can be crushed thinner than the outside when processing the corner crease 3. This makes the inside of the corner crease 3 in the cardboard sheet 1 more easily deformed (less strong) than the outside, making it easier and more appropriate to form the dent 4 in the corner of the cardboard box 2.

(3) If the thickness dimension L5 of the minor corner portion 8a adjacent to the blade end 6a in the inner elastic body 8 is smaller than the thickness dimension L6 of the portion other than the minor corner portion 8a, the blade end 6a can more easily apply pressure to the cardboard sheet 1 when processing the corner crease 3, so that the corner crease 3 can be more reliably formed into a leaf-shaped outline. Therefore, the leaf-shaped depression 4 can be more reliably formed in the corner of the cardboard box 2.

(4) The areas of the cardboard sheet 1 against which the blade end 6a is pressed are more susceptible to stress concentration and tearing than the areas against which parts of the scoring blade 6 other than the blade end 6a are pressed. In contrast, if the protruding dimension L1 of the scoring blade 6 is smaller than the protruding dimension L2 of the parts other than the blade end 6a, the pressing force applied from the blade end 6a to the cardboard sheet 1 can be reduced compared to the pressing force applied from the parts other than the blade end 6a to the cardboard sheet 1. As a result, corner creases 3 can be formed in the cardboard sheet 1 while effectively preventing tearing of the cardboard sheet 1 against which the blade end 6a is pressed.

(5) In the outer elastic body 7, if the thickness dimension L3 of the reductive corner 7a adjacent to the blade end 6a is smaller than the thickness dimension L4 of the portion other than the reductive corner 7a, the blade end 6a can more easily apply a pressing force to the cardboard sheet 1 when processing the corner crease 3, so that the corner crease 3 can be more reliably formed into a leaf-shaped outline. Therefore, the leaf-shaped depression 4 can be more reliably formed in the corner of the cardboard box 2.

(6) According to the cardboard box 2 in which the corner lines 3 have been processed by the creasing device 10, as described above, damage to the cardboard sheet 1 during processing of the corner lines 3 is suppressed, thereby improving quality.
(7) According to the scoring method, the same actions and effects as those of the scoring device 10 can be obtained.

5. Modifications
The above-mentioned relationship between the protrusion dimensions L1, L2 of the crease blade 6, the thickness dimensions L3, L4 of the outer elastic body 7, and the thickness dimensions L5, L6 of the inner elastic body 8 is one example. The protrusion dimension of the crease blade 6 may be set larger than both the thickness dimensions of the outer elastic body 7 and the inner elastic body 8. Conversely, both the thickness dimensions of the outer elastic body 7 and the inner elastic body 8 may be set larger than the protrusion dimension of the crease blade 6. Furthermore, the crease blade 6 may have a uniform protrusion dimension throughout its entirety. Similarly, the outer elastic body 7 and the inner elastic body 8 may have a uniform thickness dimension throughout its entirety.

The recess 4 formed at the corner of the cardboard box 2 may be in a leaf shape with both pointed ends located at the corners of the cardboard box 2, and may not be symmetrical about the horizontal line 16, for example. Furthermore, the cardboard box 2 is not limited to the A-type box described above.
The above-described configuration of the box making device 20 is an example. The device for manufacturing the cardboard box 2 is not limited to the above-described flexographic folder gluer, and may be, for example, a folder gluer without a printing function, a flexographic printer die cutter, or a rotary die cutter.

1 Corrugated cardboard sheet 2 Corrugated cardboard box 2A Flat box 3 Corner crease (crease)
Reference Signs 4: Depression 5: Band 6: Crease blade 6a: Blade end 6b: Fixed area 7: Outer elastic body 7a: Major angle portion 8: Inner elastic body 8a: Minor angle portion 9: Base 10: Crease processing device 11: Long side plate 12: Short side plate 13: Outer flap 14: Inner flap 15: Laminated piece 16: Horizontal crease (corrugator crease)
17 Vertical crease 20 Box making device 21 Paper feed section 22 Printing section 23 Crease insertion and grooving section 24 Die cutting section 25 Folder gluer section 26 Counter ejector section 27 Rotating drum 28 Impression drum 29 Flat plate 30 Stand A1 Rotation axis A2 of rotating drum 27 Rotation axis D1 of impression drum 28 Height direction D2 Length direction D3 Width direction Dx Horizontal direction Dy Vertical direction L1 Protrusion dimension L2 of blade end 6a Protrusion dimension L3 of portion other than fixed region 6b of crease blade 6 Thickness dimension L4 of reflex angle portion 7a Thickness dimension L5 of portion other than reflex angle portion 7a of outer elastic body 7 Thickness dimension L6 of minor angle portion 8a Thickness dimension S1 of portion other than minor angle portion 8a of inner elastic body 8 Crease formation process S2 Outer pressing process S3 Inner pressing process

Claims (6)

A creasing device for forming leaf-shaped recesses with sharp ends at corners of the box on a cardboard sheet to be assembled into a box, comprising:
a crease blade that protrudes from a base along the outline of the leaf shape and is pressed against the cardboard sheet to form the crease;
an outer elastic body formed of an elastic material softer than the crease blade and attached to the outside of the crease blade on the base;
an inner elastic body formed of an elastic material softer than the crease blade and attached to the base on the inside of the crease blade ;
The thickness dimension of the inner elastic body is equal to or greater than the thickness dimension of the outer elastic body.
A scoring device characterized by the above. A creasing device for forming leaf-shaped recesses with sharp ends at corners of the box on a cardboard sheet to be assembled into a box, comprising:
a crease blade that protrudes from a base along the outline of the leaf shape and is pressed against the cardboard sheet to form the crease;
an outer elastic body formed of an elastic material softer than the crease blade and attached to the outside of the crease blade on the base;
an inner elastic body formed of an elastic material softer than the crease blade and attached to the base on the inside of the crease blade ;
The inner elastic body has a thickness dimension of a minor corner portion adjacent to a blade end portion corresponding to both sharp ends of the leaf shape of the scoring blade, the thickness dimension being smaller than a thickness dimension of a portion other than the minor corner portion.
A scoring device characterized by the above. A creasing device for forming leaf-shaped recesses with sharp ends at corners of the box on a cardboard sheet to be assembled into a box, comprising:
a crease blade that protrudes from a base along the outline of the leaf shape and is pressed against the cardboard sheet to form the crease;
an outer elastic body formed of an elastic material softer than the crease blade and attached to the outside of the crease blade on the base;
an inner elastic body formed of an elastic material softer than the crease blade and attached to the base on the inside of the crease blade ;
The outer elastic body has a thickness dimension of a reductive corner adjacent to a blade end portion corresponding to each of the sharp ends of the leaf shape of the scoring blade, the thickness dimension being smaller than a thickness dimension of a portion other than the reductive corner portion.
A scoring device characterized by the above . A method for forming a crease on a cardboard sheet to be assembled into a box, the crease forming a leaf-shaped recess with both sharp ends of the leaf-shaped recess positioned at corners of the box, comprising:
a crease forming step of pressing a crease blade having a leaf-shaped outline against the cardboard sheet to form the crease;
an outer pressing step of pressing an outer elastic body made of an elastic material softer than the scoring blade against the outside of a portion of the cardboard sheet against which the scoring blade is pressed during the scoring step;
and an inner pressing step of pressing an inner elastic body made of an elastic material softer than the scoring blade against the inside of a portion of the cardboard sheet against which the scoring blade is pressed during the scoring step ,
The thickness dimension of the inner elastic body is equal to or greater than the thickness dimension of the outer elastic body.
A method for forming creasing lines. A method for forming a crease on a cardboard sheet to be assembled into a box, the crease forming a leaf-shaped recess with both sharp ends of the leaf-shaped recess positioned at corners of the box, comprising:
a crease forming step of pressing a crease blade having a leaf-shaped outline against the cardboard sheet to form the crease;
an outer pressing step of pressing an outer elastic body made of an elastic material softer than the scoring blade against the outside of the portion of the cardboard sheet against which the scoring blade is pressed during the scoring step;
and an inner pressing step of pressing an inner elastic body made of an elastic material softer than the scoring blade against the inside of a portion of the cardboard sheet against which the scoring blade is pressed during the scoring step ,
The inner elastic body has a thickness dimension of a minor corner portion adjacent to a blade end portion corresponding to both sharp ends of the leaf shape of the scoring blade, the thickness dimension being smaller than a thickness dimension of a portion other than the minor corner portion.
A method for forming creasing lines. A method for forming a crease on a cardboard sheet to be assembled into a box, the crease forming a leaf-shaped recess with both sharp ends of the leaf-shaped recess positioned at corners of the box, comprising:
a crease forming step of pressing a crease blade having a leaf-shaped outline against the cardboard sheet to form the crease;
an outer pressing step of pressing an outer elastic body made of an elastic material softer than the scoring blade against the outside of a portion of the cardboard sheet against which the scoring blade is pressed during the scoring step;
and an inner pressing step of pressing an inner elastic body made of an elastic material softer than the scoring blade against the inside of a portion of the cardboard sheet against which the scoring blade is pressed during the scoring step ,
The outer elastic body has a thickness dimension of a reductive corner adjacent to a blade end portion corresponding to each of the sharp ends of the leaf shape of the scoring blade, the thickness dimension being smaller than a thickness dimension of a portion other than the reductive corner portion.
A method for forming creasing lines.

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