Sheet material for packaging box and packaging box

Abstract

To secure sufficient strength while inhibiting an inner flap from downing.SOLUTION: A sheet material for a packaging box (5) includes first and second bend lines (L1-L4), (L5-L12) formed orthogonally. The sheet material is provided with first and second sidewalls (11a, 11b), (12a, 12b) arranged side by side through the first bend line, outer flaps (15a, 15b) continuing to the first sidewall through the second bend line, and inner flaps (16a, 16b) continuing to the second sidewall through the second bend line. In base portions of the outer flap closer to side edges, bend-inducing portions (L13, L14) are formed to bend preferentially to the second bend line.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a sheet material for a packaging box and a packaging box. [Background technology]

[0002] A packaging box in which a pair of inner flaps and a pair of outer flaps are provided with staggered creases is known (see, for example, Patent Document 1). In the sheet material of the unfolded packaging box described in Patent Document 1, the fold lines of the first side wall and the outer flaps are provided slightly above the fold lines of the second side wall and the inner flaps, and a difference in height is provided between the fold lines of the first side wall and the outer flaps and the fold lines of the second side wall and the inner flaps. After the pair of inner flaps are folded, the pair of outer flaps are butted together in the center of the box and sealed with tape. Even if the outer flaps are placed on top of the inner flaps during sealing, the difference in height between the fold lines prevents the inner flaps from sagging. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3726483 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the packaging box described in Patent Document 1, the heights of the fold lines of the outer and inner flaps are different, so the first side wall receives the load through the outer flap, and after the first side wall buckles, the second side wall receives the load through the inner flap, which may result in the packaging box not being strong enough to withstand the compressive load.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a sheet material for a packaging box and a packaging box that can prevent the inner flaps from sagging and ensure sufficient strength. [Means for solving the problem]

[0006] A sheet material for packaging boxes according to one embodiment of the present invention has first and second fold lines formed thereon which are perpendicular to each other, and includes a first side wall and a second side wall aligned via the first fold line, an outer flap connected to the first side wall via the second fold line, and an inner flap connected to the second side wall via the second fold line, and a bend guide portion is formed on the side edge side of the base end of the outer flap so that the outer flap bends in preference to the second fold line. Effect of the Invention

[0007] According to the present invention, the side edge side of the outer flap is not folded at the second fold line but is folded at the bending guide portion. Therefore, at the portion where the inner flap and the outer flap overlap and the rebound is strong, the inner flap and the outer flap are folded in an uneven manner, so that the sagging of the inner flap is suppressed. Also, only a part of the outer flap is folded in an uneven manner, and the outer flap is folded at the second fold line except for the side edge side of the outer flap. Therefore, the load can be received by both the first side wall and the second side wall, so that the packaging box can obtain sufficient strength against the compressive load. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing the packaging box of the present embodiment in an opened state. [Diagram 2] FIG. 2 is a perspective view showing a sealed state of the packaging box of the present embodiment. [Diagram 3] FIG. 13 is a schematic top view of a sheet material of a comparative example. [Figure 4] FIG. 2 is a plan view of the sheet material of the present embodiment. [Diagram 5] 13 is a view showing the vicinity of the base end portion of the outer lid flap of this embodiment. FIG. [Figure 6] FIG. 13 is a diagram showing an example of a staggered ruled line according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present embodiment will be described with reference to the drawings. The arrows Fr, Rr, L, R, U, and Lo in each drawing indicate the front side, rear side, left side, right side, upper side, and lower side when the packaging box is viewed from the front. In addition, although terms indicating directions and positions are used in the present embodiment, these terms are used for convenience of explanation and do not limit the technical scope of the present invention.

[0010] The packaging box of this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a perspective view showing the packaging box of this embodiment in an opened state. Fig. 2 is a perspective view showing the packaging box of this embodiment in a sealed state. Fig. 3 is a schematic top view of a sheet material of a comparative example. Fig. 4 is a plan view of the sheet material of this embodiment.

[0011] As shown in Fig. 1 and Fig. 2, the packaging box 1 is a so-called 0201 (A-type) corrugated cardboard box, and is formed so that the flaps can be folded and sealed. The packaging box 1 has a peripheral wall 10 that is rectangular when viewed from above, with long walls (first side walls) 11a, 11b facing each other in the front-rear direction and short walls (second side walls) 12a, 12b facing each other in the left-right direction. Bottom outer flaps 13a, 13b are connected to the lower edges of the long walls 11a, 11b, and bottom inner flaps 14a, 14b are connected to the lower edges of the short walls 12a, 12b. The bottom inner flaps 14a, 14b are folded inside (upper side) of the bottom outer flaps 13a, 13b, and the bottom opening of the peripheral wall 10 is sealed by the bottom outer flaps 13a, 13b.

[0012] Lid outer flaps (outer flaps) 15a, 15b are connected to the upper edges of the long walls 11a, 11b, and lid inner flaps (inner flaps) 16a, 16b are connected to the upper edges of the short walls 12a, 12b. Lid inner flaps 16a, 16b are folded inside (underside) of the lid outer flaps 15a, 15b, and the top opening of the peripheral wall 10 is sealed by the lid outer flaps 15a, 15b. The bottom outer flaps 13a, 13b are glued to the bottom inner flaps 14a, 14b to form the bottom wall of the packaging box 1. The lid outer flaps 15a, 15b are glued to the lid inner flaps 16a, 16b to form the lid wall of the packaging box 1.

[0013] 3(A), in the sheet material 31 of the comparative example, fold lines La are formed at the base ends of the outer flap 34 and the inner flap 35 by a corrugator (not shown). The corrugator is a device that forms a continuous sheet of cardboard by bonding the front and back liners and the core together, and when forming the continuous sheet, the fold lines La are formed linearly by a scorer (crisping roller) along the conveying direction of the sheet. When assembling a packaging box from this sheet material 31, the repulsion between the outer flap 34 and the inner flap 35 becomes strong at the overlapping points, which may cause poor adhesion of the flaps and an unstable package shape.

[0014] As shown in FIG. 3B, by providing a difference in height between the fold lines Lb, Lc at the base ends of the outer flap 34 and the inner flap 35, the repulsion between the flaps can be suppressed. However, since the fold lines Lb, Lc have a difference in height, the fold lines Lb, Lc cannot be formed by the scorer of the corrugator when the continuous sheet is formed. Although it is possible to form the fold lines Lb, Lc using a punching die, the printing process, the punching process, and the pasting process must be performed by separate devices. In addition, after the packaging box is made, the long wall 32 becomes higher than the short wall 33, and when the packaging boxes are stacked, the compressive load is concentrated on the long wall 32, and sufficient strength cannot be obtained.

[0015] In this case, the fold lines Lb, Lc can also be formed by the die cutter of the flexo folder gluer. However, since the sheet material 31 is transported in a direction perpendicular to the fold lines Lb, Lc, the fold lines Lb, Lc may be misaligned due to the operation timing of the die cutter, etc. When the fold lines Lb, Lc are misaligned, the lengths of the outer flap 34 and the inner flap 35 change. For example, when the outer flap 34 becomes shorter, a gap is formed when the outer flaps 34 are butted together to seal the sheets. When the outer flap 34 becomes longer, the flaps interfere with each other when the outer flaps 34 are butted together to seal the sheets.

[0016] Furthermore, as shown in FIG. 3(C), the upper fold lines Lb and Lc can be formed by a flexo folder gluer, and the lower fold line La can be formed by a corrugator. However, there are cases where the upper fold lines Lb and Lc are misaligned due to the operation timing of the die cutter, etc. When the upper fold lines Lb and Lc are misaligned, the heights of the long wall 32 and the short wall 33 change, and the storage efficiency of the packaging box after box making is unstable. Also, in the sheet material 31 shown in FIG. 3(C), the long wall 32 is higher than the short wall 33, and when the packaging boxes are stacked, the compression load is concentrated on the long wall 32, and sufficient strength cannot be obtained.

[0017] Therefore, in the packaging box 1 of this embodiment, the flaps are folded in staggered positions where they overlap and the repulsion is strong, and the other positions are folded at the same height. Even if the flaps are folded in staggered positions, the compression load is received all around, increasing the strength of the packaging box 1. Since the staggered positions are limited to a certain portion, even if the folds at the staggered positions are misaligned, the change in the length of the flaps is kept to a minimum. An example of the process from the printing process to the pasting process can be carried out by a flexo folder gluer, which is prone to misalignment, and the workload and man-hours can be reduced.

[0018] As shown in Fig. 4, the sheet material 5 shows the packaging box 1 in an unfolded state, and is formed by cutting out a single piece of cardboard sheet made of paper produced by a corrugator into a predetermined shape by punching with a flexo folder gluer. The cardboard sheet is a double-sided cardboard sheet in which a front liner and a back liner are bonded to a corrugated core 6. Note that Fig. 4 shows the cardboard sheet as seen from the front liner side. In the following explanation, the direction in which the corrugation crests of the core 6 of the cardboard sheet extend is referred to as the "corrugation direction X", and the direction perpendicular to the core 6 of the cardboard sheet is referred to as the "flow direction Y".

[0019] In the corrugator, a front liner and a back liner are attached to a corrugated core 6 to form a continuous sheet of cardboard in the flow direction Y, and a scorer 25 of the corrugator creases the continuous sheet along its extension. Therefore, fold lines L5-L12 (second fold lines) are formed in the sheet material 5 parallel to the flow direction Y. In the flexo folder gluer, the cardboard sheet is transported in the corrugation direction X, and a creaser (crease roller) 26 of the flexo folder gluer creases the cardboard sheet along its transport direction. Therefore, fold lines L1-L4 (first fold lines) are formed in the sheet material 5 parallel to the corrugation direction X.

[0020] In the sheet material 5, the seam 17, the long wall 11a, the short wall 12a, the long wall 11b, and the short wall 12b are arranged on one side of the flow direction Y via fold lines L1-L4. Rectangular outer lid flaps 15a, 15b are connected to one side of the long walls 11a, 11b in the row direction X via fold lines L5, L9, and rectangular outer bottom flaps 13a, 13b are connected to the other side of the long walls 11a, 11b in the row direction X via fold lines L6, L10. Rectangular inner lid flaps 16a, 16b are connected to one side of the short walls 12a, 12b in the row direction X via fold lines L7, L11, and rectangular inner bottom flaps 14a, 14b are connected to the other side of the short walls 12a, 12b in the row direction X via fold lines L8, L12.

[0021] The seam 17 is formed in a substantially trapezoidal shape, and the long walls 11a, 11b, the short walls 12a, 12b, the lid outer flaps 15a, 15b, the bottom outer flaps 13a, 13b, the lid inner flaps 16a, 16b, and the bottom inner flaps 14a, 14b are formed in a rectangular shape. The fold lines L1-L12 are formed by creases. The creases refer to creases formed by linearly squeezing the cardboard sheet from the back liner side. The fold lines L1-L12 may be formed so that the cardboard sheet can be folded.

[0022] In addition, staggered creases L13, L14 are formed on the side edge side of the base end of the lid outer flaps 15a, 15b as bending guide parts that bend preferentially over the fold lines L5, L9. Each of the staggered creases L13, L14 is formed of two creases that are sharper than the fold lines L5, L9 made by the corrugator. As a result, the lid outer flaps 15a, 15b bend at the staggered creases L13, L14 without bending at the fold lines L5, L9. The staggered creases L13, L14 are formed by folding creases, but may be formed by lead creases or sewing creases. A lead crease refers to a fold line in which multiple cuts are intermittently formed on a crease, and a sewing crease refers to a line in which cuts are intermittently arranged. The processing load can be reduced compared to forming the staggered creases L13, L14 by a single fold crease. Details of the staggered creases L13, L14 will be described later.

[0023] Next, the assembly work of the packaging box 1 will be described with reference to Figures 2 and 4. The packaging box 1 may be assembled manually by a worker, or automatically or semi-automatically by a box-making machine. Here, as an example, a case where a worker assembles the packaging box 1 will be described, but the order of the work of assembling the packaging box 1 can be changed as appropriate. Note that the packaging box 1 is assembled from a state in which the sheet material 5 shown in Figure 4 is folded at the fold line L3 between the short wall 12a and the long wall 11b, and the seam 17 folded back at the fold line L1 is adhered to the inner surface of the short wall 12b.

[0024] First, the long wall 11a and the short wall 12a are folded at right angles along the fold line L2, and the long wall 11b and the short wall 12b are folded at right angles along the fold line L4 to form the rectangular cylindrical peripheral wall 10. As a result, the long walls 11a and 11b face each other in the front-rear direction, and the short walls 12a and 12b face each other in the left-right direction. The bottom inner flaps 14a and 14b are folded at right angles along the fold lines L8 and L12, and the bottom outer flaps 13a and 13b are folded at right angles along the fold lines L6 and L10. The tips of the bottom outer flaps 13a and 13b are butted together, and the bottom outer flaps 13a and 13b are bonded to the bottom inner flaps 14a and 14b to form the bottom wall of the packaging box 1.

[0025] The inner lid flaps 16a, 16b are folded at right angles along the fold lines L7, L11, and the outer lid flaps 15a, 15b are folded at right angles along the fold lines L5, L9. At this time, the side edges of the outer lid flaps 15a, 15b are not folded at the fold lines L5, L9 but are folded at the staggered lines L13, L14. The outer lid flaps 15a, 15b and the inner lid flaps 16a, 16b are folded at staggered levels, so that the inner lid flaps 16a, 16b and the outer lid flaps 15a, 15b do not overlap and strengthen the repulsion. The tips of the outer lid flaps 15a, 15b are butted together, and the outer lid flaps 15a, 15b are bonded to the inner lid flaps 16a, 16b to form the lid wall of the packaging box 1.

[0026] In this type of packaging box 1, the side edges (near the corners) of the base ends of the lid outer flaps 15a, 15b are slightly higher. The side edges of the base ends of the lid outer flaps 15a, 15b are folded at the staggered creases L13, L14, but the fold lines L5, L9 are also formed on the side edges of the base ends of the lid outer flaps 15a, 15b. When a strong compressive load acts on the side edges of the base ends of the lid outer flaps 15a, 15b, the lid outer flaps 15a, 15b are crushed between the staggered creases L13, L14 and the fold lines L5, L9. The height difference between the long walls 11a, 11b and the short walls 12a, 12b is reduced, and the strength of the packaging box 1 against compressive loads is increased.

[0027] The staggered creases will be described with reference to Fig. 5. Fig. 5 is a diagram showing the periphery of the base end of the outer lid flap of this embodiment. Here, only the staggered crease L13 will be described, but the staggered crease L14 is similar. Fig. 5 shows the cardboard sheet as seen from the back liner side.

[0028] As shown in Fig. 5, a fold line L5 is formed all over the base end of the lid outer flap 15a, and a staggered crease L13 is partially formed on the side edge side of the base end of the lid outer flap 15a. The staggered crease L13 is composed of two sharp creases, each of which is inclined from the side edge of the lid outer flap 15a toward the center so as to intersect with the fold line L5. The two creases of the staggered crease L13 are formed by folding. The inclination angle of the staggered crease L13 with respect to the flow direction Y is preferably an angle at which the staggered crease L13 can bend preferentially over the fold line L5, for example, an angle of inclination of 0 degrees or more and less than 30 degrees.

[0029] The side edge of the base end of the lid outer flap 15a is folded at the staggered crease L13, and the center of the base end of the lid outer flap 15a is folded at the fold line L5. In addition, since the staggered crease L13 intersects with the fold line L5, the crease can be made more smoothly from the staggered crease L13 to the fold line L5.

[0030] The staggered crease L13 is formed by the rotary die cutter 27 of the flexographic folder gluer. As described above, in the flexographic folder gluer, the cardboard sheet is transported in the corrugation direction X, and the rotation axis of the rotary die cutter 27 extends parallel to the flow direction Y. For this reason, if there is an error in the operation timing, transport speed, or position of the attached punching die of the rotary die cutter 27, the staggered crease L13 may be misaligned. Since the staggered crease L13 is formed partially, even if the staggered crease L13 is misaligned, most of the lid outer flap 15a is folded at the fold line L5, and the effect on the flap length of the lid outer flap 15a and the height dimension of the long wall 11a is suppressed.

[0031] Since the staggered ruled lines L13 are formed by the flexo folder gluer, the work from the printing process to the pasting process can be performed by the flexo folder gluer, thereby reducing the workload and the number of work steps.

[0032] In addition, a range R1 without staggered lines L13 is secured at the center of the base end of the lid outer flap 15a so that there is no difference in height between the center of the long wall 11a and the short wall 12a when the packaging box 1 is assembled from the sheet material 5. In this case, it is preferable that the range R1 without staggered lines L13 is secured to be 30% or more of the flap width of the lid outer flap 15a. By folding the center of the base end of the lid outer flap 15a at the fold line L5, the difference in height between the long wall 11a and the short wall 12a is reduced, and the strength of the packaging box 1 against compressive load is increased. The range R2 with the staggered lines L13 may be secured asymmetrically at the side edge of the lid outer flap 15a.

[0033] Furthermore, a staggered line L13 is formed in a predetermined range R3 spaced from the fold line L5 toward the tip end of the lid outer flap 15a so that the gap between the lid outer flap 15a and the lid inner flap 16a is reduced when the packaging box 1 is assembled from the sheet material 5. In this case, it is preferable that the staggered line L13 is formed in the predetermined range R3 spaced from the fold line L5 by a length twice the thickness of the sheet material 5. By folding the side edge side of the base end of the lid outer flap 15a at the staggered line L13, the gap between the lid outer flap 15a and the lid inner flap 16a is reduced, and it is possible to prevent the intrusion of foreign matter such as dust, insects, etc. from the outside.

[0034] As described above, according to this embodiment, the side edge side of the lid outer flaps 15a, 15b is folded at the staggered lines L13, L14 without being folded at the fold lines L5, L9. Therefore, at the places where the lid inner flaps 16a, 16b and the lid outer flaps 15a, 15b overlap and the rebound is strengthened, the lid inner flaps 16a, 16b and the lid outer flaps 15a, 15b are folded at staggered levels to prevent the lid inner flaps 16a, 16b from falling. Also, only a part of the lid outer flaps 15a, 15b is folded at staggered levels, and the lid outer flaps 15a, 15b are folded at the fold lines L5, L9 except for the side edge side of the lid outer flaps 15a, 15b. Therefore, the load can be received by both the long walls 11a, 11b and the short walls 12a, 12b, so that the packaging box 1 can obtain sufficient strength against the compression load.

[0035] In this embodiment, the staggered crease is linearly inclined from the side edge of the lid outer flap toward the center so as to approach the fold line parallel to the flow direction, but the configuration is not limited to the staggered crease being linearly inclined. It is sufficient that the other end of the staggered crease located at the most central side of the lid outer flap is closer to the fold line parallel to the flow direction than one end of the staggered crease located at the most side edge side of the lid outer flap. Even with such a staggered crease, the side edge side of the lid outer flap is bent at the staggered crease, and a smooth crease can be made from the staggered crease to the fold line parallel to the flow direction.

[0036] For example, as shown in FIG. 6(A), the lid outer flap 21a may have a curved staggered line L15 in an arc shape. In this case, one end of the staggered line L15 may be curved toward the center of the lid outer flap 21a so as to approach the fold line L16, and the other end of the staggered line L15 may be curved in a direction away from the fold line L16. Also, as shown in FIG. 6(B), the lid outer flap 22a may have a staggered line L17 formed by slantingly arranging cuts parallel to the flow direction Y. The staggered line L17 is arranged from the side edge of the lid outer flap 22a toward the center so as to approach the fold line L18. The staggered lines L15, L17 in these modified examples may extend beyond the fold lines L16, L18.

[0037] In the present embodiment, the staggered crease is formed by two creases, but the staggered crease may be formed by one crease, or may be formed by three or more creases. Also, each crease may be formed by a cut crease, a fold crease, or a sewing machine crease.

[0038] Furthermore, in this embodiment, the staggered creases are inclined so as to intersect with the fold lines parallel to the flow direction, but the staggered creases may also be formed parallel to the flow direction.

[0039] In addition, in this embodiment, the staggered lines extend from the side edges of the lid outer flap toward the center, but the staggered lines may extend from a portion more inward than the side edges of the lid outer flap toward the center.

[0040] In addition, in the present embodiment, the bending guide portion is formed by a stepped crease, but the bending guide portion may be formed by any portion that bends with priority over a fold line parallel to the flow direction. For example, the bending guide portion may be formed by step-squashing the outer lid flap.

[0041] Further, in this embodiment, the fold lines parallel to the flow direction are formed by the corrugator, but the fold lines parallel to the flow direction may be formed by another processing machine.

[0042] In addition, in this embodiment, the stepped creases serving as the bend guide portions are formed by a flexo folder gluer, but the bend guide portions may be formed by other processing machines.

[0043] Further, in this embodiment, the pair of long walls and the pair of short walls of the sheet material are aligned in the flow direction, but the pair of long walls and the pair of short walls of the sheet material may be aligned in the row direction.

[0044] Further, in this embodiment, the tray is formed from a double-sided corrugated cardboard sheet, but the tray may be formed from a single-sided corrugated cardboard sheet, double-sided corrugated cardboard sheet, thick paper, a resin plate material, or the like.

[0045] As described above, the first embodiment is a sheet material (5) for a packaging box (1) having a first fold line (fold line L1-L4) and a second fold line (fold line L5-L12) that are perpendicular to each other, the sheet material (5) includes a first side wall (long wall 11a, 11b) and a second side wall (short wall 12a, 12b) arranged along the first fold line, an outer flap (15a, 15b) connected to the first side wall via the second fold line, and an inner flap (16a, 16b) connected to the second side wall via the second fold line, and a bend guide portion (stepped crease L13, L14) that bends preferentially to the second fold line is formed on the side edge side of the base end of the outer flap. According to this configuration, the side edge side of the outer flap is folded at the bend guide portion without being folded at the second fold line. Therefore, in the area where the inner flap and the outer flap overlap and the rebound is strong, the inner flap and the outer flap are folded in an uneven manner to prevent the inner flap from sagging. Also, only a part of the outer flap is folded in an uneven manner, and the outer flap is folded at the second fold line except for the side edge side of the outer flap. Therefore, the load can be received by both the first side wall and the second side wall, so that the packaging box can have sufficient strength against the compressive load.

[0046] In the second embodiment, the bend guide portion is a stepped crease (L13, L14) formed on the tip side of the outer flap from the second fold line in the first embodiment. With this configuration, the inner flap and the outer flap are folded in a stepped manner, and the inner flap and the outer flap do not overlap each other, which increases the repulsion.

[0047] In the third aspect, in the second aspect, an end of the staggered line located closest to the center of the outer flap is closer to the second fold line than an end of the staggered line located closest to the side edge of the outer flap. With this configuration, when the outer flap is folded, a crease can be made smoothly from the staggered line to the second fold line.

[0048] In a fourth aspect, in the second or third aspect, the staggered crease is inclined so as to intersect with the second fold line. With this configuration, when the outer flap is folded, a crease can be more smoothly formed from the staggered crease to the second fold line.

[0049] A fifth aspect is any one of the first to fourth aspects, in which a range (R1) without a bending guide portion is secured on the center side of the base end of the outer flap so that no difference in height occurs between the center side of the first side wall and the second side wall when the packaging box is assembled. According to this configuration, the center side of the base end of the outer flap is bent at the second fold line, thereby reducing the difference in height between the center side of the first side wall and the second side wall, and the strength of the packaging box against compressive loads can be increased.

[0050] A sixth aspect is any one of the first to fifth aspects, in which a bend guide portion is formed in a predetermined range (R3) spaced from the second fold line toward the tip end side of the outer flap so that the gap between the outer flap and the inner flap is reduced when the packaging box is assembled. According to this configuration, the side edge side of the base end portion of the outer flap is bent at the bend guide portion, thereby reducing the gap between the outer flap and the inner flap and preventing the intrusion of foreign matter such as dust, insects, etc. from the outside.

[0051] A seventh aspect is any one of the first to sixth aspects, in which the second fold line is formed by a corrugator. According to this configuration, by forming the second fold line by a corrugator, it is possible to improve the dimensional accuracy of the outer flap, the inner flap, the first side wall, and the second side wall, suppress gaps and interference between the flaps during sealing, and increase the storage efficiency and strength of the packaging box.

[0052] The eighth aspect is any one of the first to seventh aspects, in which the bend guiding portion is formed by a flexo folder gluer. With this configuration, the flexo folder gluer is used to perform the processes from the printing process to the pasting process, thereby reducing the workload and the number of steps. Even if the flexo folder gluer causes the bend guiding portion to be misaligned, most of the outer flap is folded at the second fold line. Even if misalignment occurs, the effect of the dimensions of the outer flap and the first side wall can be suppressed.

[0053] A ninth aspect is a packaging box assembled from the sheet material according to any one of the first to eighth aspects. According to this configuration, sagging of the inner flaps can be suppressed, and sufficient strength against a compressive load can be obtained.

[0054] Although the present embodiment has been described, other embodiments may be obtained by combining the above-described embodiments and modified examples in whole or in part.

[0055] In addition, the technology of the present invention is not limited to the above-mentioned embodiment, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological progress or other derived technology, it may be implemented using that method. Therefore, the scope of the utility model registration claims covers all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0056] 1: Packaging box 5: Sheet material 11a, 11b: Long wall (first side wall) 12a, 12b: Short wall (second side wall) 15a, 15b: outer flap of lid (outer flap) 16a, 16b: inner flap of the lid (inner flap) L1-L4: Fold line (first fold line) L5-L12: Broken line (second broken line) L13, L14: stepped crease (bend guidance section) R1: Area without bending guide R3: Predetermined range

Claims

1. A sheet material (5) for a packaging box (1) having a first fold line (L1-L4) and a second fold line (L5-L12) that are perpendicular to each other, a first side wall (11a, 11b) and a second side wall (12a, 12b) arranged side by side via a first fold line; an outer flap (15a, 15b) connected to the first side wall via a second fold line; and an inner flap (16a, 16b) connected to the second side wall via a second fold line; A sheet material for packaging boxes, characterized in that bending guide portions (L13, L14) that bend preferentially along the second fold line are formed on the side edge sides of the base end portions of the outer flaps.

2. 2. The sheet material for packaging boxes according to claim 1, wherein the bend guide portion is a stepped crease (L13, L14) formed on the tip side of the outer flap relative to the second fold line.

3. 3. The sheet material for packaging boxes according to claim 2, wherein the other end of the stepped crease located closest to the center of the outer flap is closer to the second fold line than the one end of the stepped crease located closest to the side edge of the outer flap.

4. 3. The sheet material for packaging boxes according to claim 2, wherein the stepped crease is inclined so as to intersect with the second fold line.

5. 2. The sheet material for packaging boxes according to claim 1, characterized in that, when the packaging box is assembled, a range (R1) in which the bending guide portion is not present is secured on the central side of the base end of the outer flap so that no difference in height occurs between the central side of the first side wall and the second side wall.

6. 2. The sheet material for packaging boxes according to claim 1, characterized in that the bending guide portion is formed in a predetermined range (R3) spaced from the second fold line toward the tip side of the outer flap so that a gap between the outer flap and the inner flap is reduced when the packaging box is assembled.

7. 2. The sheet material for packaging boxes according to claim 1, wherein the second fold lines are formed by a corrugator.

8. 8. The sheet material for packaging boxes according to claim 7, wherein the bending guide portion is formed by a flexo folder gluer.

9. A packaging box assembled from the sheet material according to any one of claims 1 to 8.

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