Paper bag

Abstract

An envelope-type paper bag (1) with no gusset comprises: a pair of cutout sections (6) that are provided in a manner of cutting off bottom corner sections (5), which are a pair of corner sections at the intersection of first imaginary lines (4L, 4R) that are imaginary downward extensions of each of a left fold line (3L) and a right fold line (3R), the bottom ends (31, 32) of which are located above a bottom fold line (3U), and second imaginary lines (41, 42) that are imaginary outward extensions in the left / right direction of the bottom fold line (3U), both ends (33, 34) of which are located to the inside in the left / right direction of both ends (9L, 9R) of an opening (9); a lower hole (7) that is a hole formed in a main surface section (2), and has a lower contour (7U) formed along the left / right direction and serving as a lower-side section of the contour enclosing the hole; and a bottom fold (10) that is a fold provided on an extension line of the lower contour (7U), both ends (1L, 1R) of said fold being connected to the cutout sections (6).

Description

paper bag

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

[0002] Conventionally, envelopes without gussets for containing flat contents are known, and gusseted envelopes for containing three-dimensional contents are also known. Gusseted envelopes are pre-folded to create a gusset between the front and back surfaces. 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 pairs of mountain fold lines, and these three fold lines are folded on the left and right sides. By folding these three fold lines, not only are the front and back surfaces overlapping, but also the planar region between the mountain fold line and the valley fold line on the front side (the front half of the gusset) and the planar region between the mountain fold line and the valley fold line on the back side (the back half of the gusset), a total of four surfaces, overlapping.

[0003] In contrast to the gusseted envelope, which is folded back along six fold lines, the front and back of an envelope, whether unused or used, are folded back along a pair of mountain fold lines, and only the front and back are folded back along two fold lines, overlapping each other. Therefore, although a gusseted envelope can accommodate more three-dimensional contents than a non-gusseted envelope, a non-gusseted envelope is less bulky than a gusseted envelope.

[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 sides, 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 the package through an opening provided at the longitudinal edge, the cuts open and the package deforms to fit the contour of the fruit (see Patent Document 1).

[0005] Japanese Patent Publication No. 2022-173847

[0006] However, the above-described cylindrical packaging body does not have a bottom surface facing the opening, making it difficult to stand upright. Similarly, envelope-shaped paper bags without gussets are also difficult to form a bottom surface facing the opening, making them difficult to stand upright. Therefore, there is room for improvement in making envelope-shaped paper bags without gussets easier to stand upright. This invention was invented in consideration of the above-described problems, and one of its objectives is to make envelope-shaped paper bags without gussets easier to stand upright. In addition to this objective, other objectives of this invention include the effects and advantages derived from the various configurations shown in the "Mode for Carrying Out the Invention" described below, which cannot be obtained with conventional technology.

[0007] The paper bag disclosed here has the following configurations (1) to (8). (1) An envelope-type paper bag without a gusset, 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 that is located at the lower edge of the main surface portions and extends in the left-right direction, and a pair of side fold lines consisting of a left fold line that is a ... A paper bag characterized by comprising: a lower hole that is drilled in the main surface portion, the lower hole having a lower contour that forms a part of the lower side of the contour surrounding the hole and that is formed along the left-right direction; and a bottom fold that is provided on an extension of the lower contour and has both ends connected to the cutout portion, and that, when folded, forms a bottom surface portion facing the opening, an upright surface portion that is erected between the opening, and the bottom surface portion on the main surface portion.

[0008] (2) The paper bag according to (1), characterized in that the bottom fold is positioned lower as it moves outward in the left-right direction. (3) The paper bag according to (1) or (2), characterized in that the bottom fold has a first fold and a second fold that are arranged side by side, and the first fold is arranged side by side below the second fold and is positioned so that the dimension of the first fold that is spaced apart from the second fold in the up-down direction increases as it moves outward in the left-right direction.

[0009] (4) The paper bag described in (3) is characterized in that a plurality of the pilot holes are provided, and the number of the second holes, which is the number of pilot holes where the second fold is provided on the extension line of the lower contour, is greater than the number of the first holes, which is the number of pilot holes where the first fold is provided on the extension line of the lower contour.

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

[0011] (7) The paper bag according to any one of (1) to (6), characterized in that the main surface portion has a hole that is disposed above the lower contour and is a hole that is separate from the lower hole. (8) The paper bag according to any one of (1) to (7), characterized in that the paper bag is made of kraft paper.

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

[0013] 1A is a perspective view showing a state of a paper bag according to an embodiment when it is not in use; 1B is a perspective view showing a state of a paper bag according to an embodiment when it is in use; 1C is a schematic view explaining a state of a paper bag according to an embodiment when it is in use, in which (a) shows a first state, (b) shows a second state, and (c) shows a third state.

[0014] A paper bag according to 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, fine 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 and before the contents are placed inside, and expand to a three-dimensional shape when the contents are placed inside. The directions used in the following explanation are defined as follows: The horizontal direction is subdivided into the front-to-back direction (in the drawings, the front is indicated by "F" and the rear by "B") and the left-to-right direction (in the drawings, the left is indicated by "L" and the right by "R"). Furthermore, within the vertical direction, the direction of gravity is defined as downward (in the drawings, "D"), and the opposite direction of downward is defined as upward (in the drawings, "U").

[0016] In the following description, a paper bag in a position where the opening for putting in and taking out contents faces upward is exemplified. 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 one 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 item [1], the paper bag when unused is described in sub-item [1-1], and then the paper bag when in use is described in sub-item [1-2].

[0018] [1-1. Configuration when unused] 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 at the front, and a rear surface portion 2B (either the first surface portion or the second surface portion) located at 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 on either side of the opening 9 through which contents are inserted and removed from 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 on 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 on 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 on either side, are slightly spaced apart, but the opening 9 is closed when the front upper edge 21 and the rear upper edge 22 are overlapped.

[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 a 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 used for 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 paper bag 1 when unused has an envelope-like shape 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 paper bag 1 when unused can be said to have a flat shape with two overlapping surfaces. This flat shape of the paper bag 1 when unused can also be said to have a sheet-like or leaf-like shape.

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

[0023] Here, the imaginary line extending the left turn line 3L downward is referred to as the left imaginary line 4L (first imaginary line), and the imaginary line extending the right turn line 3R downward is referred to as the right imaginary line 4R (first imaginary line). The imaginary line 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 extending the bottom turn line 3U to the left (outward in the left-right direction), and a right bottom imaginary line 42 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 corners 5 (hereinafter referred to as "bottom corners") where the left and right imaginary lines 4L, 4R, and the bottom imaginary line 4U intersect. 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 pair of cutouts 6 are formed by cutting out the bottom corners 5L and 5R from the paper bag 1. Of the pair of cutouts 6, the left cutout 6L is the cutout for the left bottom corner 5L, and the right cutout 6R is the cutout for the right bottom corner 5R. In other words, 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 to 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 to the right end 34 of the bottom fold line 3U.

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

[0027] Furthermore, a bottom fold 10 is provided on an extension of the lower contour 7U. The "extension" here refers to any line segment extending from the end of the lower 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 cutouts 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 bottom fold 10 illustrated here has a first fold 11 and a second fold 12 arranged side by side. Note that the first fold 11 and the second fold 12 are formed by intermittently cut perforations. However, known fold lines such as creases or lead creases that combine creases with perforations may also be applied to the first fold 11 and 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 vertical separation dimension 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 where the vertical separation dimension increases as it moves outward in the left-right direction.

[0031] The first fold 11 is not provided on an extension of the lower contour 7U of the left bottom hole 7L and the right bottom hole 7R, but is provided only on an extension of the lower contour 7U of the middle bottom hole 7C. The second fold 12 is provided not only on an extension of the lower contour 7U of the middle bottom hole 7C, but also on an extension of the lower contour 7U of the left bottom hole 7L and the right bottom hole 7R. In other words, the second fold 12 is provided on an extension of both the lower contour 7U of the middle bottom hole 7C and the lower contour 7U of the left bottom hole 7L and the right bottom 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 formed along the extension of the lower contour 7U of the first fold 11 is defined as the first hole number N1, and the number of pilot holes 7 formed along the extension of the lower contour 7U of the second fold 12 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 (three in this case) is greater than the first hole number N1 (one in this case). The second fold 12 folds the main surface portion 2 in a region excluding the lower contour 7U of the middle lower hole 7C as well as the lower contours 7U of the left lower hole 7L and the right lower hole 7R. On the other hand, the first fold 11 folds the main surface portion 2 in a region excluding only the lower contour 7U of the middle lower hole 7C. Because the region of the main surface portion 2 that does not require folding is longer along the second fold 12 than along the first fold 11, the second fold 12 is designed 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 pilot hole 7, and is positioned above the lower outline 7U of the pilot hole 7 in the main surface portion 2. In other words, the entire outline of the separate hole 8 is located above the bottom fold 10. Here, an example is given in which multiple separate holes 8 are drilled in the main surface portion 2. The separate hole 8 and the above-mentioned pilot hole 7 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, the separate hole 8 and pilot 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 for keeping the opening 9 closed is provided at the top of the main surface portion 2. The closing fold 90 extends between the upper edges 21, 22 of the front surface portion 2F and the back surface portion 2B and the side fold lines 3L, 3R, and is a fold that guides the folding of the upper left and upper right corners of the main surface portion 2. When the unused paper bag 1 having the above-described configuration is folded, the paper bag 1 for use, which will be described next, is formed.

[0036] [1-2. Configuration during 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, the portion of the front portion 2F above the bottom fold 10 in the unused paper bag 1 stands upright in the front half as the front upright portion 3F, and the portion of the rear portion 2B above the bottom fold 10 in the unused paper bag 1 stands upright in the rear half as the rear upright portion 3B. In the paper bag 1 illustrated here 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, forms a space like a gusseted envelope when in use, capable of containing contents with a dimension in the front-to-back direction.

[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 the folded portion of the bottom fold 10 forms an arched leg. As shown in Figures 3(a) to 3(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 one of the three shapes described below.

[0039] As shown in Figure 3(a), in a first configuration in which the first fold 11 is not folded and only the second fold 12 is folded (Figure 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 a 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 surface portion 20 and the upright surface portion 30.

[0040] As shown in Figure 3(c), in a third configuration in which only the first fold 11 is folded without folding 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 forward and backward. The tapered region 13 facing forward and backward in this manner may be treated as part of the upright 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 crease 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 surface 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 surface portion 20 and the upright surface portion 30 can be improved by the cutout portion 6, the pilot hole 7, and the bottom crease 10, making it easier for the paper bag 1 to stand on its own.

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

[0043] Furthermore, because the bottom fold is located on an extension of the lower contour 7U, the bottom portion 20 and the vertical portion 30 can be folded without bending the lower contour 7U. This also reduces the bending force required to fold the bottom portion 20 and the vertical portion 30. By improving the folding formability of the bottom portion 20 and the vertical portion 30 as described above, the gussetless envelope-shaped paper bag 1 can stand upright stably.

[0044] (2) When the paper bag 1 is unused, the bottom crease 10 is positioned lower as it moves outward in the left-right direction, so the folded portion of the bottom crease 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 crease 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 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, whose vertical separation increases outward in the left-right direction. The tapered region 13 functions like an arched leg supporting the bottom portion 20. This also allows the paper bag 1 to stand stably on its own.

[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 line 3U is folded back to fold the bottom fold 10, the bending force caused by the folding back of the bottom fold line 3U is transmitted in the order of the folds closest to the bottom fold line 3U, i.e., the first fold 11 and the second fold 12. In terms of the order of the bending force transmission, the first fold 11, to which the bending force is transmitted first, may be more easily bent 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 formed on the extension line of the lower contour 7U for the second fold 12, is set to be greater than the first number of holes N1, which is the number of pilot holes 7 formed on the extension line of the lower contour 7U for the first fold 11. 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 holes 7 include a middle lower hole 7C located in the center of the paper bag 1 in the left-right direction. This allows the bottom fold 10 to 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 located only on an extension of the lower contour 7U of the middle lower hole 7C. Furthermore, the second fold 12 is located 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] Because the second fold 12 is provided not only on the extension of the lower contour 7U of the middle lower hole 7C but also on the extension 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 fold, can be ensured if attention is paid to the order of transmission of the bending force, as described above in (4). Because both the first fold 11 and the second fold 12 are provided on the extension of the lower contour 7U of the middle lower hole 7C, the first fold 11 and the second fold 12 can be folded in a balanced manner from left to right, as described above in (5).

[0051] (7) The pilot holes 7 and the separate holes 8 allow the interior of the paper bag 1 to be visible from the outside, even if the paper bag 1 is made of opaque paper. Alternatively, at least some of the 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. Note that the pilot holes 7 and the separate holes 8 remove weight from the main surface portion 2, making it easier to deform the main surface portion 2 to a shape that corresponds to the outer shape of the contents. This contributes to increasing the flexibility to accommodate 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" movement) compared to a plastic packaging bag, and can be recycled as waste paper. (9) In addition, by folding the upper left and upper right corners of the main surface 2 at the closing fold 90 when using the paper bag 1, the opening 9 of the paper bag 1 containing the contents can be kept slightly closed, 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 described in this embodiment. Each configuration of this embodiment can be modified in various ways without departing from the spirit of the invention. Furthermore, the configurations can be selected and combined as needed.

[0054] The paper bag is envelope-shaped without a gusset, and only needs to have a notch, a pilot hole, and a bottom fold. For example, the number of pilot holes is not limited to three, but may be one (single), two, or four or more. The number of first holes and the number of second holes may also be set 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 fold is also not limited to a bottom fold that is 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.

[0056] 1 Paper bag 10 Bottom fold 11 First fold 12 Second fold 13 Tapered region 1L Left edge 1R Right edge 2 Main surface portion 20 Bottom surface portion 21 Front upper edge (upper edge) 22 Rear upper edge (upper edge) 2B Rear surface portion (the other of the first surface portion and the second surface portion) 2F Front surface portion (either the first surface portion or the second surface portion) 30 Elevation portion 31 Left lower edge (lower edge) 32 Right lower edge (lower edge) 33 Left edge (both ends) 34 Right edge (both ends) 3B Rear elevation portion 3F Front elevation portion 3L, 3R Pair of side fold lines 3L Left fold line 3R Right fold line 3U Bottom fold line 41 Left bottom imaginary line (second imaginary line) 42 Right bottom imaginary line (second imaginary line) 4L Left imaginary line (first imaginary line) 4R Right imaginary line (first imaginary line) 4U Bottom imaginary line (second imaginary line) 5 Bottom corner 5L Left bottom corner 5R Right bottom corner 6 Cutout 6L Left cutout 6R Right cutout 7 Bottom hole 7U Bottom contour 7C Middle bottom hole (center hole) 7L Left bottom hole (other hole) 7R Right bottom hole (other hole) 8 Separate hole 9 Opening 90 Closing fold 9L Left end (both ends) 9R Right end (both ends)

Claims

1. An envelope-type paper bag without a gusset, 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 that is located on the lower edge of the main surface portions and extends in the left-right direction, and a pair of side fold lines consisting of a left fold line that is a ... A paper bag characterized by comprising: a lower hole that is drilled in the main surface portion, the lower hole having a lower contour that forms a part of the lower side of the contour surrounding the hole and that is formed along the left-right direction; and a bottom fold that is provided on an extension of the lower contour and has both ends connected to the cutout portion, and that, when folded, forms a bottom surface portion facing the opening, an upright surface portion that is erected between the opening, and the bottom surface portion on the main surface portion.

2. The paper bag according to claim 1, characterized in that the bottom folds are positioned lower as they move outward in the left-right direction.

3. The paper bag according to claim 1 or 2, characterized in that the bottom fold has a first fold and a second fold arranged side by side, and the first fold is arranged side by side below the second fold and is positioned so that the dimension of the first fold spaced apart from the second fold in the vertical direction increases as it moves outward in the left-right direction.

4. The paper bag according to claim 3, characterized in that a plurality of the pilot holes are provided, and the number of the second holes, which is the number of pilot holes where the second fold is provided on an extension of the lower contour, is greater than the number of the first holes, which is the number of pilot holes where the first fold is provided on an extension of the lower contour.

5. The paper bag according to any one of claims 1 to 4, characterized in that the pilot hole has a center hole located in the center in the left-right direction.

6. A paper bag as described in claim 5, which cites claims 3 or 4, characterized in that the first fold is provided only on an extension of the lower contour of the center hole, and the second fold is provided on an extension 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.

7. A paper bag as described in any one of claims 1 to 6, characterized in that the main surface portion has a separate hole that is positioned above the lower contour and is separate from the lower hole.

8. The paper bag according to any one of claims 1 to 7, characterized in that it is made of kraft paper.

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