Crease processing device, cardboard box, and crease processing method

Abstract

To suppress breakage of a corrugated cardboard sheet when processing of ruled lines that form the shape of tree leaves is performed.SOLUTION: This invention relates to a ruled line processing device 10 which executes ruled line processing to form a recess having a leaf shape and sharp ends of the leaf shape located at corners of the box, for a cardboard sheet to be assembled into a box. The ruled line processing device comprises: a ruled line blade 6 protruding from a base 9 in a leaf shape contour; and an external elastic body 7 and an internal elastic body 8 formed of an elastic material more flexible than the ruled line blade 6, wherein the ruled line blade 6 forms ruled lines by being pressed against the cardboard sheet, the external elastic body 7 is mounted on the outside of the ruled line blade 6 at the base 9, and the internal elastic body 8 is mounted inside the ruled blade 6 at the base 9.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an apparatus for forming creases in cardboard sheets to be assembled into boxes, a cardboard box formed with creases by this apparatus, and a method for forming creases in the cardboard sheets. [Background technology]

[0002] 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 problem, Patent Document 1 proposes a technique in which leaf-shaped lines (creases) are provided at the corners of a cardboard box, and the parts surrounded by these lines are recessed inwardly into the cardboard box. According to 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 59-38224 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned creases are formed by pressing a crease blade that forms the leaf-shaped outline against the cardboard sheet to be assembled into a cardboard box. When creasing a closed shape like this, the crease blade is more likely to cause a large localized tensile force in the cardboard sheet compared to, for example, when creasing a straight line. This poses the problem that the cardboard sheet is more likely to tear.

[0005] The present invention was invented in consideration of the above problems, and one of its objectives is to prevent the cardboard sheet from tearing when the scoring is performed. However, other objectives of the present invention are to achieve the effects and advantages derived from the configurations shown in the "Mode for Carrying Out the Invention" described later, which cannot be obtained by the conventional technology. [Means for solving the problem]

[0006] The present scoring device is a scoring device that processes score lines in cardboard sheets to be assembled into a box, so as to form leaf-shaped depressions with both sharp ends of the leaf shape located at the corners of the box, and is characterized in that it comprises a scoring blade that protrudes from a base along the outline of the leaf shape and forms the score lines by being pressed against the cardboard sheets, an outer elastic body that is formed from an elastic material that is softer than the scoring blade and attached to the outside of the scoring blade on the base, and an inner elastic body that is formed from an elastic material that is softer than the scoring blade and attached to the inside of the scoring blade on the base.

[0007] The cardboard box of the present invention is characterized in that the creases are formed by the above-mentioned crease forming device.

[0008] The present scoring method is a method for processing score lines in cardboard sheets to be assembled into a box, the score lines being designed to form leaf-shaped depressions with both sharp ends of the leaf shape located at corners of the box, and is characterized by comprising: a score forming step of pressing a score blade forming the contour of the leaf shape against the cardboard sheet to form the score lines; an outer pressing step of, during the score forming step, pressing an outer elastic body formed of an elastic material softer than the score blade against the outside of the portion of the cardboard sheet against which the score blade is pressed; and an inner pressing step of, during the score forming step, pressing an inner elastic body formed of an elastic material softer than the score blade against the inside of the portion of the cardboard sheet against which the score blade is pressed. Effect of the Invention

[0009] According to the present invention, tearing of the cardboard sheet during the processing of the scoring lines can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] 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. [Diagram 2] FIG. 2 is a perspective view showing a state in which a cardboard box according to one embodiment is banded. [Diagram 3] 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). [Figure 4] 1 is a block diagram showing a configuration of a box making device according to an embodiment; [Diagram 5] FIG. 2 is a side view of a rotating drum to which the scoring device according to the embodiment is applied. [Figure 6] FIG. 13 is a side view of a flat plate to which a crease processing device according to one modified example is applied. [Figure 7] FIG. 2 is a plan view of the scoring device according to the embodiment. [Figure 8] 8 is a side view of a main part of the scoring device according to the embodiment (viewed in the direction of the arrow B in FIG. 7). FIG. [Figure 9] 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). [Figure 10] 1 is a chart showing a crease processing method according to an embodiment. [Figure 11] 13 is a chart showing a method for processing lines according to one modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following describes the embodiments for carrying out the present invention. The embodiments described below are merely examples, and are not intended to exclude various modifications or application of techniques not specifically described herein. The configurations of the following embodiments can be modified in various ways without departing from the spirit of the invention. In addition, they can be selected or combined as necessary.

[0012] [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, the cardboard sheet 1 is assumed to be developed in a plane, and two directions perpendicular to each other in the plane in which the cardboard sheet 1 extends are defined as the horizontal direction Dx and the vertical direction Dy. In the cardboard sheet 1 of this embodiment, a hollow portion formed by the corrugated core extends along the vertical direction Dy.

[0013] The cardboard sheet 1 includes 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.

[0014] Here, a cardboard sheet 1 is illustrated 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).

[0015] At the boundaries between the long side panels 11 and the outer flaps 13 and at the boundaries between the short side panels 12 and the inner flaps 14, linear horizontal creases (corrugator creases) 16 extending in the horizontal direction Dx 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 of the long side panels 11 and the bonding piece 15, linear vertical creases 17 extending in the vertical direction Dy are provided. Both the horizontal creases 16 and the vertical creases 17 are creases (grooves) processed in the cardboard sheet 1, and serve to guide 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.

[0016] The cardboard sheet 1 is machined with creases 3 forming 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 of this embodiment are shaped by sharpening both ends in the horizontal direction Dx of an ellipse that is longer in the horizontal direction Dx than in the vertical direction Dy. The corner creases 3 are closed shapes since they form the 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 sharpened ends (portions with both ends on the major axis of the ellipse sharpened) are the intersections.

[0017] Both sharp ends of corner crease 3 are located on horizontal crease 16 which will become the corners of cardboard box 2. Corner crease 3 is a crease (groove) for forming leaf-shaped depression 4 (see FIG. 2) at the corner of cardboard box 2. Corner crease 3 in this embodiment is formed line-symmetrically with respect to horizontal crease 16 on which it overlaps. Note that horizontal crease 16, vertical crease 17 and corner crease 3 are all formed on the same surface (back surface) of cardboard sheet 1.

[0018] The corrugated cardboard sheet 1 has two corner creases 3 formed thereon, which overlap with 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 exemplified here. For example, the corner creases 3 may be disposed so as to overlap with 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 with a gap in the horizontal direction Dx for one horizontal crease 16. The corner crease 3 can be effective even if it is 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 to provide the corner crease 3 on each of the two horizontal creases 16 (the horizontal creases 16 extending along the boundaries between the long side panel 11 and both outer flaps 13).

[0019] The 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 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.

[0020] 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. Additionally, 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 side surfaces 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.

[0021] 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 pointed ends located on the horizontal line 16. The recess 4 has the 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 underside. 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.

[0022] A strip-shaped band 5 is wound around the cardboard box 2. The band 5 is a so-called PP band made of plastic. The band 5 is arranged so as to fasten the long side panel 11 and the outer flap 13 from the outside, and prevents the outer flap 13 from being unintentionally opened. Note that, although Fig. 2 shows an example of one cardboard box 2 with the band 5 wound around it, multiple cardboard boxes 2 may be integrated together by wrapping the band 5 around multiple cardboard boxes 2.

[0023] The bands 5 are fixed in contact with the recesses 4 of the cardboard box 2. In this way, the bands 5 are arranged so as to fit into the recesses 4, which prevents the bands 5 from shifting out of position or falling out of the cardboard box 2. Furthermore, although a fastening force by the bands 5 acts on the recesses 4 of the cardboard box 2, stress concentration due to the fastening force of the bands 5 is mitigated at the corners that are made obtuse by the recesses 4. Therefore, damage to the corners of the cardboard box 2 caused by the fastening force of the bands 5 is prevented.

[0024] [2. Box making equipment] [2-1. Overall composition] 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 on the cardboard box 2 to forming the box 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 in Fig. 4, both the cardboard sheet 1 and the flat box 2 are shown as a bundle.

[0025] 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. A sheet-like corrugated cardboard sheet 1 that has been pre-cut into a rectangular shape of a predetermined size is supplied to the paper feed section 21. The above-mentioned horizontal lines 16 have been formed in advance in this corrugated cardboard sheet 1.

[0026] The cardboard sheet 1 sent out from the paper feed section 21 is printed on its surface with desired characters and patterns in the printing section 22. Next, the cardboard sheet 1 is grooved and creasingd by a slotter device and a creaser device provided in the creasing and grooving section 23. Next, in the die-cutting section 24, the cardboard sheet 1 is punched and cut. In the folder-gluer unit 25, the corrugated cardboard sheet 1 is folded and glued, thereby forming a flat box 2A. The flat boxes 2A are then stacked while being counted in the counter-ejector unit 26, and are discharged as a batch of a predetermined number.

[0027] [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 is mounted on the circumferential surface of a cylindrical rotating drum 27 in the die-cutting section 24. 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.

[0028] 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 in the stationary cardboard sheet 1 when the cardboard sheet 1 is sandwiched between the flat platen 29 and a stand 30 arranged below it.

[0029] As shown in Fig. 7, the scoring device 10 includes a scoring blade 6 protruding from a base 9, and an outer elastic body 7 and an inner elastic body 8 formed of an elastic material more flexible than the scoring blade 6. In Fig. 7 and Fig. 8 described later, the outer elastic body 7 is indicated by light dots, and the inner elastic body 8 is indicated by dark dots. The base 9 is, for example, a mold in which the scoring blade 6 is embedded and fixed. The base 9 is fixed to the circumferential surface of the rotating drum 27 by a fixture or adhesive (not shown). Although Fig. 7 shows a flat base 9, a 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.

[0030] The ruled line blade 6 has a leaf-shaped contour corresponding to the angular ruled line 3 and the recess 4. The ruled line blade 6 demarcates the leaf shape corresponding to the recess 4 in a plan view of the base 9. That is, the ruled line blade 6 has a closed shape similar to the angular ruled line 3. The ruled line blade 6 forms the angular ruled line 3 on the corrugated cardboard sheet 1 by being pressed against the corrugated cardboard sheet 1. The ruled line blade 6 is formed of, for example, metal. Hereinafter, each of the portions corresponding to the pointed ends of the leaf shape of the ruled line blade 6 is also referred to as a "blade end portion 6a". The blade end portion 6a is a portion forming the contour of the pointed ends of the leaf shape. The blade end portion 6a is pressed against the horizontal ruled line 16 that becomes the corner of the corrugated cardboard box 2 in the corrugated cardboard sheet 1.

[0031] As shown in FIG. 8, in the ruled line blade 6 of the present embodiment, the protruding dimension L1 of the blade end portion 6a from the base 9 is formed to be smaller than the protruding dimension from the base 9 of the portion other than the blade end portion 6a. In other words, in the ruled line blade 6, the protruding dimension L2 of the blade end portion 6a is the minimum protruding dimension. In the present embodiment, an example of the ruled line blade 6 in which the protruding dimension from the base 9 gradually decreases as it approaches the blade end portion 6a in a certain region 6b including the blade end portion 6a is illustrated. That is, in the certain region 6b, the tip, which is the protruding end of the ruled line blade 6, is inclined toward the base 9 side as it approaches the blade end portion 6a. Note that, in the portion other than the certain region 6b, the protruding dimension L2 of the ruled line blade 6 is made uniform (L1 < L2). Therefore, in the ruled line blade 6, the protruding dimension L2 of the portion other than the certain region 6b is the maximum protruding dimension.

[0032] Hereinafter, with reference to the ruled line blade 6, the side where the region surrounded by the ruled line blade 6 is located is referred to as the "inner side", and the opposite side is referred to as the "outer side". As shown in FIG. 7, the outer elastic body 7 is attached to the outside of the ruled line blade 6 on the base 9. Also, the inner elastic body 8 is attached to the inside of the ruled line 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 ruled line blade 6 protrudes. Note that the fixing method of the outer elastic body 7 and the inner elastic body 8 to the base 9 is not particularly limited, and for example, a fixing tool (not shown) may be used, or an adhesive may be used.

[0033] The outer elastic body 7 is provided so as to surround the ruled line blade 6 in a plan view of the base 9. In the present embodiment, an example of the outer elastic body 7 having an outer shape that is slightly larger than the shape of a leaf outlined by the ruled line blade 6 is illustrated. The outer elastic body 7 is pressed against a region surrounding the angular ruled line 3 (the region outside the angular ruled line 3) in a plan view of the cardboard sheet 1.

[0034] On the other hand, the inner elastic body 8 is provided in a region surrounded by the ruled line blade 6 in a plan view of the base 9. In the present embodiment, an example of the inner elastic body 8 having a shape that coincides with the shape of a leaf outlined by the ruled line blade 6 (that is, a shape corresponding to the recess 4 formed in the cardboard box 2) is illustrated. The inner elastic body 8 is pressed against a region surrounded by the angular ruled line 3 (the region inside the angular ruled line 3 and the region that becomes the recess 4 in the cardboard box 2) in a plan view of the cardboard sheet 1.

[0035] Here, the thickness dimensions of the outer elastic body 7 and the inner elastic body 8 will be described in detail. The thickness dimension referred to here corresponds to the protruding dimension of the outer elastic body 7 and the inner elastic body 8 from the base 9. As shown in FIG. 9, in the outer elastic body 7, the thickness dimension L3 of the obtuse angle portion 7a adjacent to the blade end portion 6a is formed to be smaller than the thickness dimension L4 of the portion other than the obtuse angle portion 7a (L3 < L4). In FIG. 9, among the obtuse angle portions 7a, the thickness dimension of the portion closest to the blade end portion 6a is indicated by the symbol "L3". In the present embodiment, an example of the obtuse angle portion 7a whose thickness dimension L3 is reduced as it approaches the blade end portion 6a is illustrated. That is, the top surface of the obtuse angle portion 7a (the surface that contacts the cardboard sheet 1 during the processing of the angular ruled line 3) is inclined toward the base 9 side as it approaches the adjacent blade end portion 6a. On the other hand, for the portion other than the obtuse angle portion 7a of the outer elastic body 7, the thickness dimension L4 is uniform. Therefore, in the outer elastic body 7, the thickness dimension L4 of the portion other than the obtuse angle portion 7a forms the maximum thickness dimension.

[0036] The inner elastic body 8 is formed such that the thickness dimension L5 of the obtuse angle portion 8a adjacent to the blade end portion 6a is smaller than the thickness dimension L6 of the portion other than the obtuse angle portion 8a (L5 < L6). In FIG. 9, among the obtuse angle portions 8a, the thickness dimension of the portion closest to the blade end portion 6a is indicated by the symbol "L5". In the present embodiment, an example of the obtuse angle portion 8a whose thickness dimension L5 is reduced as it approaches the blade end portion 6a is illustrated. That is, the top surface of the obtuse angle portion 8a (the surface that contacts the cardboard sheet 1 during the processing of the grid line 3) slopes downward toward the base 9 as it approaches the adjacent blade end portion 6a. On the other hand, for the portion of the inner elastic body 8 other than the obtuse angle portion 8a, the thickness dimension L6 is uniform. Therefore, in the inner elastic body 8, the thickness dimension L6 of the portion other than the obtuse angle portion 8a forms the maximum thickness dimension.

[0037] The thickness dimension of the inner elastic body 8 of the present embodiment is set to be equal to or greater than the thickness dimension of the outer elastic body 7. Specifically, 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 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. That is, the inner elastic body 8 is formed thicker than the outer elastic body 7 in all or most of it (the portion excluding a part of the obtuse angle portion 8a).

[0038] In the present embodiment, the maximum thickness dimension L6 of the inner elastic body 8 is set to be greater than the maximum protrusion dimension L2 of the grid line blade 6 (L2 < L6). Therefore, the inner elastic body 8 protrudes from the base 9 more than the grid line blade 6. Also, the thickness dimensions L3, L4 of the outer elastic body 7 are set to be smaller than the protrusion dimensions L1, L2 of the grid line blade 6 (L3 < L4 < L1 < L2). In other words, the outer elastic body 7 is set to have a thickness dimension smaller than the minimum protrusion dimension L2 of the grid line blade 6 throughout its entirety.

[0039] 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 cellular 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 cellular sponge, and the inner elastic body 8, which is thicker than the outer elastic body 7, may be formed by stacking two pieces of black cellular 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 but varying the number of layers, the above-mentioned relationship in thickness can be achieved while improving ease of manufacture.

[0040] 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: 7mm Maximum thickness dimension L6 of inner elastic body 8: 14mm

[0041] [3. Method] The scoring method according to this embodiment is carried out by the above-mentioned scoring device 10. As shown in Fig. 10, the scoring method includes a scoring forming step S1 in which a scoring blade 6 is pressed against a cardboard sheet 1 to form a corner score 3, an outer pressing step S2 in which an outer elastic body 7 is pressed against the outer side of the portion of the cardboard sheet 1 against which the scoring blade 6 is pressed, and an inner pressing step S3 in which an inner elastic body 8 is pressed against the inner side of the portion of the cardboard sheet 1 against which the scoring blade 6 is pressed.

[0042] The outer pressing step S2 and the inner pressing step S3 are performed during the execution of the creasing step S1. In other words, the three steps S1 to S3 are performed 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 with the rotation of the rotating drum 27 on which the creasing device 10 is mounted. For this reason, the outer pressing step S2 is started first, then the creasing step S1 is started, and then the inner pressing step S3 is started. Thereafter, the inner pressing step S3 is completed first, then the creasing step S2 is completed, and then the outer pressing step S2 is completed.

[0043] 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 magnitude 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 the crease processing method performed by the crease processing device 10 attached to the flat platen 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 platen 29, the three steps S1 to S3 are started 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 are ended in the reverse order.

[0044] [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. This allows the outer elastic body 7 and the inner elastic body 8 to hold the cardboard sheet 1 against the tensile force generated when the scoring blade 6 bites into the cardboard sheet 1, thereby suppressing localized elongation (stress concentration) of the cardboard sheet 1. This makes it possible to suppress damage to the cardboard sheet 1 when the corner scores 3 are processed.

[0045] In particular, when the horizontal creases 16 of the cardboard sheet 1 are corrugator creases formed in advance by a slitter scorer of a corrugator during the manufacture of the A-type cardboard box 2, the corrugator creases (horizontal creases 16) are formed stronger than normal creases formed by a flexo folder gluer. In this case, in order to more reliably form the recesses 4 at the corners of the cardboard box 2, it is necessary to process the corner creases 3 deeper than the horizontal creases 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 crease blade 6 processes the corner creases 3 as described above, so that localized stretching of the cardboard sheet 1 is suppressed. Therefore, even when the crease blade 6 is pressed against the cardboard sheet 1 with the horizontal creases 16 formed therein with a strong force, damage to the cardboard sheet 1 can be suppressed. In this way, the creasing device 10 is particularly effective when forming corner creases 3 on an A-type cardboard box 2.

[0046] (2) If the thickness dimension of inner elastic body 8 is equal to or greater than the thickness dimension of outer elastic body 7, the inside of corner crease 3 in cardboard sheet 1 can be crushed thinner than the outside when processing corner crease 3. This makes the inside of corner crease 3 in cardboard sheet 1 more susceptible to deformation (lower strength) than the outside, making it possible to form dents 4 more easily and appropriately in the corners of cardboard box 2.

[0047] (3) In the inner elastic body 8, if 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, 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 the leaf-shaped outline. Therefore, the leaf-shaped depression 4 can be more reliably formed in the corner of the cardboard box 2.

[0048] (4) The portions of the cardboard sheet 1 against which the blade end 6a is pressed are more susceptible to stress concentration and tearing than the portions against which the other parts of the scoring blade 6 are pressed. In contrast, if the protruding dimension L1 of the blade end 6a of the scoring blade 6 is smaller than the protruding dimension L2 of the other parts of the scoring blade 6, 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 other parts of the scoring blade 6 to the cardboard sheet 1. This makes it possible to effectively prevent tearing of the portions of the cardboard sheet 1 against which the blade end 6a is pressed, while still forming the corner creases 3 in the cardboard sheet 1.

[0049] (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 apply a pressing force to the cardboard sheet 1 more easily when processing the corner crease 3, so that the corner crease 3 can be more reliably formed into the leaf-shaped outline. Therefore, the leaf-shaped depression 4 can be more reliably formed in the corner of the cardboard box 2.

[0050] (6) According to the cardboard box 2 in which the corner creases 3 have been processed by the creasing device 10, damage to the cardboard sheet 1 during the processing of the corner creases 3 is suppressed as described above, thereby improving quality. (7) According to the creasing method, the same actions and effects as those of the creasing device 10 can be obtained.

[0051] [5. Modifications] The above-mentioned relationship between the protruding dimensions L1, L2 of the scoring 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 protruding dimension of the scoring 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 protruding dimension of the scoring blade 6. Furthermore, the scoring blade 6 may have a uniform protruding dimension throughout its entirety. Similarly, the outer elastic body 7 and the inner elastic body 8 may have a uniform thickness dimension throughout their entirety.

[0052] The recess 4 formed in 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 does not have to be, for example, symmetrical about the horizontal line 16. In addition, the cardboard box 2 is not limited to the A-type box as 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 flexo folder gluer, and may be, for example, a folder gluer without a printing function, a flexo printer die cutter, or a rotary die cutter. [Explanation of symbols]

[0053] 1 cardboard sheet 2. Cardboard Box 2A flat box 3 Corner lines (lines) 4. Dent 5 Bands 6 Crease blade 6a Blade end 6b Fixed area 7 External elastic body 7a Superior corner 8 Internal elastic body 8a inferior angle part 9 Foundation 10. Crease processing device 11 Long side plate 12 Short side plate 13 Outer flap 14 Inner flap 15 Pasting piece 16 Horizontal lines (corrugator lines) 17 Vertical lines 20 Box making equipment 21 Paper feed section 22 Printing Department 23 Crease and groove cutting section 24 Die-cut section 25 Folder gluer section 26 Counter ejector section 27 Rotating Torso 28 Impression cylinder 29 flat plate 30 units A1 Rotation axis of the rotating body 27 A2 Rotation axis of the impression cylinder 28 D1 Height direction D2 Length direction D3 Width direction Dx Horizontal Dy Vertical L1: Protruding dimension of the blade end 6a L2: Protruding dimension of the portion of the crease blade 6 other than the fixed region 6b L3 Thickness dimension of the corner part 7a L4: Thickness dimension of the outer elastic body 7 at the portion other than the gentle corner portion 7a L5 Thickness dimension of minor angle portion 8a L6: Thickness dimension of the inner elastic body 8 at the portion other than the minor corner portion 8a S1 Crease formation process S2 External pressing process S3 Inner pressing process

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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 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.

6. 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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