Paper bag

Abstract

To make a non-gusseted paper bag of an envelope type easy to self-stand.SOLUTION: A non-gusseted paper bag 1 of an envelope type comprises: a pair of cut-outs 6 that are provided in a state of cutting away a pair of bottom corners 5 assuming corner portions where first virtual lines 4L, 4R given by virtually extending downward respective ones of left and right fold-back line 3L, 3R having lower ends 31, 32 arranged upper than a bottom fold-back line 3U and second virtual lines 41, 42 given by virtually extending outward in a right-left direction the bottom fold-back line 3U having both ends 33, 34 arranged inner in the right-left direction than both ends 9L, 9R of an opening 9 intersect with each other; a lower hole 7 that is made open in a main face portion 2 and has a lower contour 7U assuming a lower part of a contour surrounding the hole and formed along the right-left direction; and a bottom crease 10 that is a crease provided on an extension line of the lower contour 7U and having both ends 1L, 1R connected to the cut-outs 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an envelope-type paper bag without a gusset. [Background technology]

[0002] BACKGROUND ART Envelopes without gussets that can accommodate flat contents are known, and gusseted envelopes that can accommodate three-dimensional contents are also known. Gusseted envelopes are pre-folded to create a gusset between the front and back sides. When a gusseted envelope is unused, it has a mountain fold line on the front side, a mountain fold line on the back side, and a valley fold line between these two mountain fold lines, and these three fold lines are folded in on the left and right sides. By folding in these three fold lines, not only are the front and back sides overlapped, but also a total of four sides are overlapped: the planar area between the mountain fold line and the valley fold line on the front side (the front half of the gusset) and the planar area between the mountain fold line and the valley fold line on the back side (the back half of the gusset).

[0003] In contrast to the gusseted envelopes that are folded over on six fold lines on the left and right sides as described above, the front and back sides of the envelope without a gusset are folded over on a pair of mountain fold lines on the left and right sides, whether the envelope is unused or in a used state, and only the front and back sides, which are folded over on two fold lines on the left and right sides, are overlapped. Therefore, although a gusseted envelope can accommodate more three-dimensional contents than an envelope without a gusset, an envelope without a gusset is less bulky than an envelope with a gusset.

[0004] In response to this, a gussetless, cylindrical package has been proposed that ensures sufficient storage capacity for the contents while being less bulky when unused. The proposed package has a first sheet corresponding to either the front or back side and a second sheet corresponding to the other of the front or back side, glued together at the left and right side edges, with staggered cuts provided along the longitudinal direction (i.e., the up-down direction) perpendicular to the left-right direction. When fruit is placed into this package through an opening provided at the longitudinal edge, the cuts open and the package deforms, allowing it to conform to the contours of the fruit (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-173847 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the cylindrical packaging described above does not have a bottom surface facing the opening, making it difficult to stand upright. Similarly, envelope-type paper bags without gussets also have difficulty forming a bottom surface facing the opening, making them difficult to stand upright. Therefore, there is room for improvement in making it easier for envelope-type paper bags without gussets to stand upright. The present invention was invented in consideration of the above-mentioned problems, and one of its objectives is to make it easier for gusset-less envelope-shaped paper bags to stand upright. However, other objectives of the present invention are not limited to this objective. The functions and effects derived from the various configurations shown in the "Mode for Carrying Out the Invention" below, which cannot be obtained with conventional technology, can also be considered as other objectives of the present invention. [Means for solving the problem]

[0007] The paper bag disclosed here has the following features (1) to (8). (1) A gussetless envelope-type paper bag, in which a pair of main surface portions, each consisting of a first surface portion whose upper edge is located on one side of the opening and a second surface portion whose upper edge is located on the other side of the opening, are connected by only three fold lines: a bottom fold line which is located at the lower edge of the main surface portions and extends along the left-right direction, a left fold line which is a fold line which is a fold line which extends along the up-down direction on the left edge of the main surface portions, and a right fold line which is a fold line which is a fold line which extends along the up-down direction on the right edge of the main surface portions, a pair of cutouts in which bottom corner portions, which are a pair of corners where a first imaginary line is an imaginary downward extension of each of the left fold line and the right fold line, whose lower ends are located above the bottom fold line, and a second imaginary line is an imaginary extension of the bottom fold line, whose ends are located inside the left and right ends of the opening, to the outside in the left and right direction, intersect; a lower hole formed in the main surface portion, the lower hole having a lower contour that forms a part of a lower side of a contour surrounding the hole and that is formed along the left-right direction; a bottom fold that is provided on an extension line of the lower contour and has both ends connected to the notch, and that is folded to form a bottom surface portion facing the opening, an upright surface portion erected between the opening, and the bottom surface portion on the main surface portion. A paper bag characterized by:

[0008] (2) The bottom fold is positioned lower toward the outside in the left-right direction. The paper bag according to (1) above. (3) the bottom fold has a first fold and a second fold arranged side by side; The first fold is provided below the second fold and in parallel with the second fold, and is provided at a position where the dimension of the first fold apart from the second fold in the up-down direction increases toward the outer side in the left-right direction. The paper bag according to (1) or (2) above.

[0009] (4) The pilot holes are provided in plurality, The bottom fold has a first hole number, which is the number of the pre-holes formed on the extension line of the lower contour of the first fold, and a second hole number, which is the number of the pre-holes formed on the extension line of the lower contour of the second fold, that is, is greater than a first hole number, which is the number of the pre-holes formed on the extension line of the lower contour of the first fold. The paper bag according to (3) above.

[0010] (5) The pilot hole has a center hole disposed in the center in the left-right direction. The paper bag according to any one of (1) to (4) above, (6) the first fold is provided only on an extension line of the lower contour of the center hole, The second fold is provided on an extension line of both the lower contour of the center hole and the lower contour of another hole that is a hole different from the center hole among the lower holes. A paper bag according to (3), (4) or (5) citing (3), characterized in that

[0011] (7) a hole that is disposed above the lower contour in the main surface portion and is a hole that is different from the lower hole; The paper bag according to any one of (1) to (6) above, (8) Made of kraft paper The paper bag according to any one of (1) to (7) above, [Effects of the Invention]

[0012] According to this invention, it is possible to make it easier for an envelope-type paper bag without a gusset to stand upright. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing the paper bag according to an embodiment when it is unused. [Figure 2] FIG. 1 is a perspective view showing a paper bag according to an embodiment in use. [Figure 3]1A to 1C are schematic diagrams illustrating the forms of the paper bag according to the embodiment when in use, where (a) shows a first form, (b) shows a second form, and (c) shows a third form. DETAILED DESCRIPTION OF THE INVENTION

[0014] The paper bag as an embodiment will be described below. The paper bag of this embodiment is a gussetless, envelope-shaped paper bag. This paper bag can be made from paper materials such as kraft paper, wood-free paper, medium-quality paper, art paper, coated paper, cast-coated paper, inkjet recording paper, Clupak paper, liner paper, and white paperboard. It can also be made from laminated paper, in which a thermoplastic resin such as polyethylene resin is laminated on one or both sides of these papers and paperboards; nonwoven fabrics such as spunbond and spunlace; plastic sheets such as synthetic paper and film; and paper materials such as laminated paper and corrugated cardboard. Among these, paper and paperboard are suitable for use as sheet materials for paper bags because they are easy to recycle from waste paper. Kraft paper, Clupak paper, and paperboard are particularly suitable for use as sheet materials for paper bags because of their excellent strength. The sheet materials for paper bags may have a coating layer on one or both sides for the purposes of imparting water resistance, printability, and improving strength.

[0015] As described above, paper bags, which can be made from a variety of paper materials, are flat when unused before the contents are placed inside, and when used with the contents placed inside, they expand to form a three-dimensional shape according to the outer shape of the contents. The directions used in the following explanation are defined as follows: The horizontal direction is further divided into the front-to-back direction (in the drawings, front is indicated by "F" and rear is indicated by "B") and the left-to-right direction (in the drawings, left is indicated by "L" and right is indicated by "R"). Furthermore, within the vertical direction, the direction of gravity is defined as downward (indicated by "D" in the drawings), and the opposite direction of downward is defined as upward (indicated by "U" in the drawings).

[0016] In the following description, a paper bag is exemplified in a position where the opening through which contents are put in and taken out faces upward. In the paper bag of this embodiment, all or at least some of the components may be arranged symmetrically from left to right or from front to back, or all or at least some of the components may be arranged asymmetrically from left to right or from front to back.

[0017] I. ONE EMBODIMENT In the following embodiment, the configuration of the paper bag is described in item [1], and the action and effect of the configuration of item [1] is described in item [2]. [1. Configuration] In this section [1], we will explain the paper bag when unused in subsection [1-1], and then explain the paper bag when in use in subsection [1-2].

[0018] [1-1. Shape when not in use] As shown in Figure 1, when unused, the paper bag 1 has no fold lines for gussets, and the pair of front and rear main surface portions 2 are connected by only three fold lines 3L, 3R, and 3U. The pair of front and rear main surface portions 2 are composed of a front surface portion 2F (either the first surface portion or the second surface portion) located in the front, and a rear surface portion 2B (either the first surface portion or the second surface portion) located in the rear. If the front of the paper bag 1 is the front side and the rear side is the back side, the front surface portion 2F is located on the front side and the rear surface portion 2B is located on the back side.

[0019] The upper edges 21, 22 of the front portion 2F and the rear portion 2B are arranged at the front and rear of the opening 9, through which contents are put in and taken out of the paper bag 1. The upper edge 21 of the front portion 2F (hereinafter referred to as the "front upper edge") is arranged in front of the opening 9 (either one side or the other). The upper edge 22 of the rear portion 2B (hereinafter referred to as the "rear upper edge") is arranged behind the opening 9 (either one side or the other). The paper bag 1 in Figure 1 illustrates a state in which the front upper edge 21 and the rear upper edge 22, which sandwich the opening 9 from the front and rear, are slightly spaced apart, but when the front upper edge 21 and the rear upper edge 22 are overlapped, the opening 9 is closed.

[0020] The three fold lines 3L, 3R, 3U include a pair of left and right (i.e., two) side fold lines 3L, 3R extending in the up-down direction, and one bottom fold line 3U extending in the left-right direction. Note that the fold lines 3L, 3R, 3U illustrated here are creases. However, known fold lines such as intermittent perforations or lead creases that combine perforations and creases may also be applied to the fold lines 3L, 3R, 3U.

[0021] The pair of left and right side fold lines 3L, 3R consists of one left fold line 3L and one right fold line 3R. The left fold line 3L is located on the left edge of the main surface portion 2. The right fold line 3R is located on the right edge of the main surface portion 2. The bottom fold line 3U is located on the bottom edge of the main surface portion 2. By folding the main surface portion 2 only along these three fold lines 3L, 3R, and 3U, the unused paper bag 1 has an envelope-like shape with no gusset, with only the two layers of the front surface portion 2F and the back surface portion 2B overlapping. If each of the main surface portions 2 is considered to be a single surface, the unused paper bag 1 can be said to have a flat shape with two surfaces overlapping. In this way, the flat shape of the unused paper bag 1 can also be said to have a sheet-like shape or a leaf-like shape.

[0022] The three folding lines 3L, 3R, and 3U are not continuous and are spaced apart from one another. The lower end (hereinafter referred to as the "lower left end") 31 of the left turn line 3L is located above the bottom turn line 3U. Similarly, the lower end (hereinafter referred to as the "lower right end") 32 of the right turn line 3R is located above the bottom turn line 3U. The left end 33 and the right end 34 (both left and right ends) of the bottom fold line 3U are located laterally inward of the left end 9L and the right end 9R (both left and right ends) of the opening 9.

[0023] Here, the imaginary line obtained by imaginarily extending the left turn line 3L downward is referred to as the left imaginary line 4L (first imaginary line), and the imaginary line obtained by imaginarily extending the right turn line 3R downward is referred to as the right imaginary line 4R (first imaginary line). Furthermore, the imaginary line obtained by imaginarily extending the bottom turn line 3U outward in the left-right direction is referred to as the bottom imaginary line 4U (second imaginary line). The bottom imaginary line 4U includes a left bottom imaginary line 41, which is an imaginary line obtained by imaginarily extending the bottom turn line 3U to the left (outward in the left-right direction), and a right bottom imaginary line 42, which is an imaginary line obtained by imaginarily extending the bottom turn line 3U to the right (outward in the left-right direction).

[0024] The paper bag 1 of this embodiment has a pair of cutouts 6 formed by cutting out a pair of corner portions (hereinafter referred to as "bottom corner portions") 5 where the left virtual line 4L and right virtual line 4R intersect with the bottom virtual line 4U. The bottom corners 5 include a left bottom corner 5L where the left imaginary line 4L intersects with the left bottom imaginary line 41, and a right bottom corner 5R where the right imaginary line 4R intersects with the right bottom imaginary line 42. These pair of left and right bottom corners 5 are cut out from the paper bag 1 as if they were cut out.

[0025] The portions where the bottom corners 5L and 5R are cut out from the paper bag 1 are a pair of cutouts 6. Of the pair of cutouts 6, the portion where the left bottom corner 5L is cut out is the left cutout 6L, and the portion where the right bottom corner 5R is cut out is the right cutout 6R. That is, the left cutout 6L corresponds to the outline surrounding the left bottom corner 5L, excluding the left imaginary line 4L and the left bottom imaginary line 41. This left cutout 6L can also be described as the area connecting the lower left end 31 of the left fold line 3L and the left end 33 of the bottom fold line 3U. Similarly, the right cutout 6R corresponds to the outline surrounding the right bottom corner 5R, excluding the right imaginary line 4R and the right bottom imaginary line 42. This right cutout 6R can also be described as the area connecting the lower right end 32 of the right fold line 3R and the right end 34 of the bottom fold line 3U.

[0026] In the paper bag 1 of this embodiment, a pilot hole 7 is drilled in the main surface portion 2. Here, an example in which the pilot hole 7 is drilled on the lower side of the main surface portion 2 will be described. The lower hole 7 has a lower contour 7U that forms a part of the lower side of the contour surrounding the lower hole 7 (hole) and is formed along the left-right direction. The illustrated lower hole 7 has three (plural) lower holes 7C, 7L, and 7R as shown below. Note that the left lower hole 7L and the right lower hole 7R are obviously different from the middle lower hole 7C. Middle bottom hole 7C (center hole): Bottom hole 7 located in the center of the paper bag 1 in the left-right direction Left lower hole 7L (other hole): Lower hole 7 located to the left of the middle lower hole 7C Right lower hole 7R (other hole): Lower hole 7 located to the right of the middle lower hole 7C

[0027] Furthermore, a bottom fold 10 is provided on an extension of the bottom contour 7U. The "extension" here means any line extending from the end of the bottom contour 7U. This extension is not limited to curves with a constant curvature, but also includes curves with an inconstant curvature. While FIG. 1 illustrates an example in which the bottom fold 10 is provided on a curved extension, the bottom fold 10 may also be provided on a straight extension.

[0028] The bottom fold 10 is a fold whose left and right ends 1L, 1R are connected to the cutout 6. Specifically, the left end 1L of the bottom fold 10 is connected to the left cutout 6L, and the right end 1R of the bottom fold 10 is connected to the right cutout 6R. The bottom fold 10 is positioned lower as it moves outward in the left-right direction. In other words, the bottom fold 10 is provided with an upward convex shape.

[0029] The illustrated bottom fold 10 has a first fold 11 and a second fold 12 arranged side by side. The first fold 11 and the second fold 12 are formed by intermittently cutting perforations. However, well-known fold lines such as ruled lines and lead creases that are perforations in addition to ruled lines may also be used. It may be applied to the first fold 11 or the second fold 12.

[0030] The first fold 11 is arranged below and parallel to the second fold 12. The first fold 11 is arranged at a position where the dimension of the vertical separation between the first fold 11 and the second fold 12 increases as it moves outward in the left-right direction. The space between the first fold 11 and the second fold 12 is defined as a tapered region 13 whose vertical separation increases toward the outer side in the left-right direction.

[0031] The first fold 11 is not provided on an extension of the lower contour 7U of the left lower hole 7L and the right lower hole 7R, but is provided only on an extension of the lower contour 7U of the middle lower hole 7C. The second fold 12 is provided not only on the extension line of the lower contour 7U of the middle hole 7C but also on the extension line of the lower contour 7U of the left hole 7L and the right hole 7R. In other words, the second fold 12 is provided on the extension line of both the lower contour 7U of the middle hole 7C and the lower contour 7U of the left hole 7L and the right hole 7R.

[0032] As described above, the first fold 11 is provided on the extension of the lower contour 7U of one of the three pilot holes 7 (specifically, the middle pilot hole 7C), whereas the second fold 12 is provided on the extension of the lower contours 7U of all three pilot holes 7. Because the second fold 12 is provided on the extension of the lower contours 7U of all three pilot holes 7, the lower contours 7U of the left pilot hole 7L and the right pilot hole 7R are located on the extension of the lower contour 7U of the middle pilot hole 7C.

[0033] Here, if the number of pilot holes 7 where the first fold 11 is formed on an extension line of the lower contour 7U is defined as the first hole number N1, and the number of pilot holes 7 where the second fold 12 is formed on an extension line of the lower contour 7U is defined as the second hole number N2, then the inequality "first hole number N1 < second hole number N2" holds. In other words, the second hole number N2 (here, three) is greater than the first hole number N1 (here, one). The second fold 12 folds the main surface portion 2 in an area excluding the lower contour 7U of the middle bottom hole 7C as well as the lower contours 7U of the left bottom hole 7L and the right bottom hole 7R. On the other hand, the first fold 11 folds the main surface portion 2 in an area excluding only the lower contour 7U of the middle bottom hole 7C. As such, the area of ​​the main surface portion 2 that does not need to be folded is longer at the second fold 12 than at the first fold 11, and therefore the second fold 12 is arranged to bend more easily than the first fold 11.

[0034] The paper bag 1 exemplified in this embodiment has a separate hole 8 in addition to the pilot hole 7 . The separate hole 8 is a hole separate from the lower hole 7, and is positioned above the lower contour 7U of the lower hole 7 on the main surface portion 2. That is, the entire contour of the separate hole 8 is located above the bottom fold 10. Here, an example will be given in which a plurality of separate holes 8 are drilled in the main surface portion 2. The separate hole 8 and the lower hole 7 described above penetrate the main surface portion 2 from front to back, and are therefore holes (communicating holes) that connect the inside and outside of the paper bag 1. Since the main surface portion 2 cannot be seen through a paper bag 1 made of opaque paper material, the separate hole 8 and the lower hole 7 can be said to be holes that make the inside of the paper bag 1 visible from the outside.

[0035] In addition, a closing fold 90 is provided on the upper portion of the main surface portion 2 to keep the opening 9 closed. The closing fold 90 extends between the upper edges 21, 22 of the front surface 2F and the rear surface 2B and the side fold lines 3L, 3R, and guides the folding of the upper left and right corners of the main surface 2. The unused paper bag 1 having the above-described structure is folded to form the paper bag 1 for use, which will be described next.

[0036] [1-2. Form when in use] When in use, the paper bag 1 is formed by folding the bottom crease 10 of the unused paper bag 1, folding back the bottom fold line 3U, and folding back the left and right side fold lines 3L, 3R. In the paper bag 1 thus folded, the front upper edge 21 and the rear upper edge 22 are separated from each other, leaving the opening 9 open, as shown in Figure 2. In this paper bag 1 with the opening 9 open, the main surface 2 is formed with a bottom surface 20 facing the opening 9 and an upright surface 30 standing between the bottom surface 20 and the opening 9. In other words, the bottom crease 10 is folded to form the upright surface 30 and the bottom surface 20 on the main surface 2.

[0037] In the upright portion 30, when the paper bag 1 is unused, the portion of the front portion 2F above the bottom fold 10 stands upright in the front half as the front upright portion 3F, and when the paper bag 1 is unused, the portion of the rear portion 2B above the bottom fold 10 stands upright in the rear half as the rear upright portion 3B. In the illustrated paper bag 1 when in use, the front upright portion 3F is curved so that the center in the left-right direction bulges forward, and the rear upright portion 3B is curved so that the center in the left-right direction bulges backward. In other words, the paper bag 1, which is an envelope-shaped bag without a gusset when unused, becomes an envelope-shaped bag with a gusset when in use, and is capable of containing a space with dimensions in the front-to-back direction that can accommodate contents.

[0038] When the paper bag 1 is in use, the bottom fold 10 is positioned lower as it moves outward in the left-right direction, so that the folded portion of the bottom fold 10 forms an arch-like leg. As shown in Figures 3(a) to (c), the tapered region 13 defined between the first fold 11 and the second fold 12 of the bottom fold 10 can be folded into any of the three configurations described below.

[0039] 3(a), in the first configuration in which the first fold 11 is not folded and only the second fold 12 is folded (FIG. 3(a) shows an example in which the second fold 12 is folded at a right angle or approximately a right angle), the tapered region 13 extends in the front-to-back and left-to-right directions and faces downward. This downward tapered region 13 may be treated as part of the bottom surface portion 20. As shown in Figure 3(b), in the second configuration in which both the first fold 11 and the second fold 12 are folded (Figure 3(b) shows an example in which the second fold 12 is folded at an angle of approximately 45°), the tapered region 13 faces diagonally downward between the bottom portion 20 and the upright portion 30.

[0040] As shown in Figure 3(c), in a third configuration in which only the first fold 11 is folded without the second fold 12 (Figure 3(c) shows an example in which the first fold 11 is folded at a right angle or approximately a right angle), the tapered region 13 extends in the vertical and horizontal directions and faces front and rear. The tapered region 13 facing front and rear in this manner may be treated as part of the vertical portion 30.

[0041] [2. Actions and Effects] The paper bag 1 of this embodiment has the above-described configuration, and therefore can achieve the following actions and effects. (1) When unused, the paper bag 1 is folded at the bottom fold 10, the bottom fold line 3U is folded back, and the left and right side fold lines 3L, 3R are folded back, forming the bottom portion 20 facing the opening 9. This makes it easier for the paper bag 1 to stand on its own. Furthermore, the foldability of the bottom portion 20 and the upright portion 30 can be improved by the cutouts 6, the pilot holes 7, and the bottom fold 10, making it easier for the paper bag 1 to stand on its own.

[0042] Specifically, because cutout 6 is provided with bottom corner 5 cut away, it is possible to avoid the repulsive force and interference of bottom corner 5 caused by folding bottom corner 5 when folding along bottom fold 10, compared to folding the bottom and vertical sections from a paper bag in which the bottom corners are not cut away. This makes it possible to prevent wrinkles and kinks from occurring in bottom section 20 and vertical section 30, and also reduces the bending force required to fold bottom section 20 and vertical section 30.

[0043] Furthermore, because the bottom fold is provided on an extension line of the lower contour 7U, the bottom surface portion 20 and the vertical surface portion 30 can be formed by bending without bending the lower contour 7U. This also reduces the bending force required to bend the bottom surface portion 20 and the vertical surface portion 30. As described above, the improved folding formability of the bottom surface portion 20 and the upright surface portion 30 allows the gussetless envelope-shaped paper bag 1 to stand stably.

[0044] (2) When the paper bag 1 is unused, the bottom fold 10 is positioned lower as it moves outward in the left-right direction, so the folded portion of the bottom fold 10 forms an arch-like leg, which helps the paper bag 1 to stand upright stably when in use. To give a specific example, the folded portion of the bottom fold 10 forms an upwardly convex arch when viewed from the front to back, which can particularly prevent the bag from shaking or tipping over in the left-right direction.

[0045] (3) When unused, the paper bag 1 has a bottom fold 10 in which the vertical separation between the first fold 11 and the second fold 12 increases as it moves outward in the left-right direction. In the second and third forms shown in Figures 3(b) and 3(c), this bottom fold 10 forms a tapered region 13 between the first fold 11 and the second fold 12, where the vertical separation increases as it moves outward in the left-right direction. The tapered region 13 functions like an arched leg that supports the bottom surface 20. This also allows the paper bag 1 to stand upright stably.

[0046] In the second configuration shown in Fig. 3(b), both the first fold 11 and the second fold 12 are folded, and a tapered region 13 is formed between the first fold 11 and the second fold 12. On the other hand, in the third configuration shown in Fig. 3(c), the second fold 12 is not folded, and the tapered region 13 is formed between the first fold 11 and the second fold 12 while the first fold 11 is folded.

[0047] (4) When the bottom fold 10 is folded by folding back the bottom fold line 3U, the bending force caused by folding back the bottom fold line 3U is transmitted in the order of the folds closest to the bottom fold line 3U, that is, the first fold 11 and the second fold 12. If we pay attention to the order in which the bending force is transmitted, the first fold 11, to which the bending force is transmitted first, is more likely to bend than the second fold 12, and the second fold 12 may be more difficult to bend than the first fold 11.

[0048] In contrast, the second number of holes N2, which is the number of pilot holes 7 for the second fold 12 on an extension of the lower contour 7U, is set to be greater than the first number of holes N1, which is the number of pilot holes 7 for the first fold 11 on an extension of the lower contour 7U. By setting the numbers of holes N1 and N2 in this way, the ease of folding the second fold 12 is improved, and the bendability of the second fold 12 can be ensured.

[0049] (5) The lower hole 7 has a middle lower hole 7C located in the center of the left-right direction of the paper bag 1. Therefore, the bottom fold 10 can be folded in a balanced manner from left to right, improving the folding formability of the paper bag 1. (6) Furthermore, the first fold 11 is provided only on an extension of the lower contour 7U of the middle lower hole 7C. The second fold 12 is provided on an extension of both the lower contour 7U of the middle lower hole 7C and the lower contours 7U of the left lower hole 7L and the right lower hole 7R.

[0050] Since the second fold 12 is provided not only on the extension line of the lower contour 7U of the middle lower hole 7C but also on the extension line of the lower contour 7U of the left lower hole 7L and the right lower hole 7R, the bendability of the second fold 12, which is difficult to bend, can be ensured by paying attention to the order in which the bending force is transmitted, as described above in (4). Since both the first fold 11 and the second fold 12 are located on the extension line of the lower contour 7U of the middle lower hole 7C, as described above in (5), the first fold 11 and the second fold 12 can each be folded in a balanced manner on the left and right.

[0051] (7) The pilot hole 7 and the separate hole 8 allow the inside of the paper bag 1 to be seen from the outside even if the paper bag 1 is made of opaque paper. Alternatively, at least some of the multiple separate holes 8 (for example, holes provided on the upper side of the main surface portion 2) can be utilized as hand holes through which the user of the paper bag 1 can put their fingers when carrying the paper bag 1. Furthermore, by removing weight from the main surface portion 2 using the pilot holes 7 and the additional holes 8, it is possible to easily deform the main surface portion 2 to a shape that corresponds to the outer shape of the contents. This contributes to increasing the flexibility in accommodating contents of various shapes that can be placed in the paper bag 1.

[0052] (8) A paper bag 1 made of kraft paper does not require the use of resin materials (promoting the so-called "plastic-free" approach) compared to plastic packaging bags, and can be recycled as waste paper. (9) In addition, when the paper bag 1 is in use, the upper left and upper right corners of the main surface portion 2 are folded at the closing fold 90, so that the opening 9 of the paper bag 1 containing the contents can be kept slightly closed, thereby preventing the contents from flying out from inside the paper bag 1 or foreign objects from entering inside the paper bag 1.

[0053] [II. Modifications] The above-described embodiment is merely an example, and is not intended to exclude various modifications and application of techniques not explicitly stated in this embodiment. Each configuration of this embodiment can be modified and implemented in various ways without departing from the spirit of the invention. Furthermore, it is possible to select and combine as needed.

[0054] The paper bag is an envelope-type bag without a gusset, and is provided with at least a notch, a pilot hole, and a bottom fold. For example, the number of the pilot holes is not limited to three, but may be one (single), two, or four or more. In addition, the number of the first holes and the number of the second holes may be set to be equal, and the arrangement of the pilot holes is also arbitrary.

[0055] The first and second folds of the bottom fold are not limited to a relative arrangement in which the vertical separation increases toward the left-right outer side, but can be arranged in any relative arrangement. The bottom folds are also not limited to being positioned lower toward the left-right outer side, but can be arranged in any extended arrangement. Furthermore, only one of the first and second folds may be provided as the bottom fold. The separate hole may be omitted from the paper bag, and the paper material used for the paper bag is not limited to kraft paper. [Explanation of symbols]

[0056] 1 paper bag 10 bottom fold 11 First fold 12 Second fold 13 Tapered Region 1L left end 1R right end 2 Main surface 20 Bottom part 21 Front upper edge (upper edge) 22 Rear upper edge (upper edge) 2B Rear surface (either the first surface or the second surface) 2F Front section (either the first or second section) 30 Elevation 31 Lower left edge (lower edge) 32 Lower right edge (lower edge) 33 Left end (both ends) 34 Right end (both ends) 3B Rear elevation 3F front elevation 3L, 3R Pair of side fold lines 3L Left turn line 3R right turn line 3U bottom fold line 41 Left bottom imaginary line (second imaginary line) 42 Right bottom imaginary line (second imaginary line) 4L Left virtual line (first virtual line) 4R Right virtual line (first virtual line) 4U bottom virtual line (second virtual line) 5 Bottom corner 5L bottom left corner 5R Bottom right corner 6 Notch 6L Left notch 6R Right notch 7. Pre-drilling 7U lower contour 7C Center hole 7L Lower left hole (other hole) 7R Lower right hole (other hole) 8 Separate hole 9 aperture 90 Closed fold 9L Left end (both ends) 9R Right end (both ends)

Claims

1. A gussetless envelope-type paper bag, in which a pair of main surface portions, each consisting of a first surface portion whose upper edge is located on one side of the opening and a second surface portion whose upper edge is located on the other side of the opening, are connected by only three fold lines: a bottom fold line which is located at the lower edge of the main surface portions and extends along the left-right direction, a left fold line which is a fold line which is a fold line which extends along the up-down direction on the left edge of the main surface portions, and a right fold line which is a fold line which is a fold line which extends along the up-down direction on the right edge of the main surface portions, a pair of cutouts in which bottom corner portions, which are a pair of corners where a first imaginary line is an imaginary downward extension of each of the left fold line and the right fold line, whose lower ends are located above the bottom fold line, and a second imaginary line is an imaginary extension of the bottom fold line, whose ends are located inside the left and right ends of the opening, to the outside in the left and right direction, intersect; a lower hole formed in the main surface portion, the lower hole having a lower contour that forms a part of a lower side of a contour surrounding the hole and that is formed along the left-right direction; a bottom fold that is provided on an extension line of the lower contour and has both ends connected to the notch, and that is folded to form a bottom surface portion facing the opening, an upright surface portion erected between the opening, and the bottom surface portion on the main surface portion. A paper bag characterized by:

2. The bottom fold is positioned lower toward the outside in the left-right direction. The paper bag according to claim 1 .

3. the bottom fold has a first fold and a second fold arranged side by side; The first fold is provided below the second fold and in parallel with the second fold, and is provided at a position where the dimension of the first fold apart from the second fold in the up-down direction increases toward the outer side in the left-right direction. The paper bag according to claim 1 or 2.

4. The pilot holes are provided in plurality, The bottom fold has a first hole number, which is the number of the pre-holes formed on the extension line of the lower contour of the first fold, and a second hole number, which is the number of the pre-holes formed on the extension line of the lower contour of the second fold, that is, a larger number of the pre-holes formed on the extension line of the lower contour of the second fold. The paper bag according to claim 3.

5. The pilot hole has a center hole disposed in the center in the left-right direction. The paper bag according to claim 4.

6. the first fold is provided only on an extension line of the lower contour of the center hole, The second fold is provided on an extension line of both the lower contour of the center hole and the lower contour of another hole that is a hole different from the center hole among the lower holes. The paper bag according to claim 5.

7. a hole that is disposed above the lower contour in the main surface portion and is a hole that is different from the lower hole; The paper bag according to claim 1 .

8. Made of kraft paper The paper bag according to claim 1 .

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