JP2016222333A - Corrugated board box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrugated board box where a flap can be smoothly cut off and cracks between the flap and a peripheral wall are less likely to be caused when boxing commodities.SOLUTION: A groove-shaped normal ruled line 15 having a recessed side of a rear liner 2 is formed between upper flaps 11, 12, 13 and 14 and a peripheral wall 31. Perforations 16 for cutting off the upper flaps 11, 12, 13 and 14 are formed by being superposed on the normal ruled line 15. A groove-shaped reverse ruled line 17 having a recessed side of a front liner 1 is formed at a position with a space at upper flaps 11, 12, 13 and 14 sides to the normal ruled line 15 and in parallel with the normal ruled line 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a corrugated board box, a perforation forming method for a corrugated board sheet, and a perforation forming unit.

  In general, a cardboard box is assembled by folding a cardboard having a front liner, a back liner, and a core provided between the two liners so that the back liner is inside. Here, in order to facilitate the opening operation of the cardboard box, a corrugated cardboard box in which a perforation for breaking is provided on the peripheral wall is known, and a corrugating machine suitable for manufacturing a cardboard sheet forming such a cardboard box The thing of patent document 1 is proposed.

  In the corrugating machine described in Patent Document 1, a liner cutting device that forms a perforation for breaking on a back liner is disposed on the upstream side of a slitter scorer. Here, the slitter scorer is a unit in which a scorer that forms a ruled line on a cardboard sheet and a slitter that divides the cardboard sheet into a plurality of sheets are integrated. The ruled line formed on the cardboard sheet by the scorer is usually a ruled line between the peripheral wall of the cardboard box and the flap. This ruled line is a groove-like ruled line (normal ruled line) in which the side of the back liner is recessed so that the flap is folded inside the peripheral wall.

Japanese Patent No. 4545346

  The inventor of the present application studied to form a perforation for separating the flap on a normal ruled line between the flap and the peripheral wall in order to improve the opening of the cardboard box. In this way, it is possible to easily separate the flap from the peripheral wall along the perforation formed so as to overlap the regular ruled line, and it is possible to easily open the cardboard box.

  However, actually, the inventors of the present application prototyped a plurality of cardboard boxes formed by overlapping perforations on the normal ruled line between the flap and the peripheral wall, and evaluated those cardboard boxes. It was found that there was a risk of cracking between the flap and the peripheral wall along the perforation when packing.

  That is, when packing a product, the flap may be folded to the outside of the peripheral wall (so-called reverse folding) in order to facilitate the insertion of the product into the cardboard box. Here, since the regular ruled line between the flap and the peripheral wall is a groove shape with the back liner side recessed, when folding the flap inside the peripheral wall, it can be folded without difficulty along the normal ruled line However, when the flap is folded to the outside of the peripheral wall, the flap cannot be folded unless a relatively large force is applied, and at this time, excessive tension acts on the back liner side. And, when the perforation is formed on the normal ruled line between the flap and the peripheral wall, when the flap is folded along the normal ruled line to the outside of the peripheral wall, the tension acting on the back liner side, It has been found that there is a risk of cracking between the flap and the peripheral wall along the perforation.

  The problem to be solved by the present invention is to provide a corrugated cardboard box in which the flap can be smoothly separated and the product is not easily cracked between the flap and the peripheral wall when the product is boxed.

In order to solve the above problems, the present invention provides a cardboard box having the following configuration.
A peripheral wall formed by bending a cardboard having a front liner, a back liner, and a core provided between the front liner and the back liner into a tubular shape so that the back liner is inside;
In a cardboard box having a flap connected to one end of the peripheral wall,
Between the flap and the peripheral wall, a groove-like regular ruled line is formed with a concave side of the back liner so that the flap is folded inside the peripheral wall.
A perforation for separating the flap is formed on the regular ruled line,
A groove-like reverse ruled line is formed at a position spaced from the normal ruled line on the side of the flap, in parallel with the normal ruled line, so that the front liner side is recessed so that the flap is folded outside the peripheral wall. A cardboard box characterized by being made.

  If it does in this way, since a normal ruled line and a perforation are overlapped and formed between a flap and a peripheral wall, a flap can be smoothly separated along the normal ruled line and a perforation. In addition, the reverse ruled line formed at a position spaced apart from the normal ruled line on the flap side is formed in a groove shape with the front liner side recessed, so when the flap is folded outside the peripheral wall (so-called In the reverse folding, the flap does not break at the normal ruled line on which the perforation is formed, but it folds along the reverse ruled line without the perforation. Therefore, when boxing goods, it can prevent that a crack arises along the perforation between a flap and a peripheral wall.

  The depth of the reverse ruled line is preferably equal to or greater than the depth of the normal ruled line.

  In this way, when the flap is folded to the outside of the peripheral wall, it is possible to prevent the flap from being folded along the normal ruled line, and to be surely folded along the reverse ruled line.

  The reverse ruled line is preferably arranged so that a distance between the center of the normal ruled line and the center of the reverse ruled line is 5 mm or more and 20 mm or less.

  In this case, since the distance between the center of the normal ruled line and the center of the reverse ruled line is 5 mm or more, it is possible to prevent the normal ruled line and the reverse ruled line from being broken simultaneously when the flap is folded outside the peripheral wall. In addition, since the distance between the center of the normal ruled line and the center of the reverse ruled line is 20 mm or less, when the flap is folded outside the peripheral wall, the flap is effectively prevented from being folded along the normal ruled line without being folded at the reverse ruled line. can do.

In addition, the present invention provides a perforation forming method having the following configuration as a perforation forming method for a corrugated cardboard sheet suitable for manufacturing the corrugated cardboard box.
A corrugated sheet having a front liner, a back liner, and a core provided between the front liner and the back liner, a groove-like normal ruled line with a concave side of the back liner, and a concave side of the front liner A crease-like reverse ruled line, a ruled line forming step for forming the normal ruled line and the reverse ruled line so as to extend parallel to each other at an interval;
A perforation forming step of forming a perforation extending in the same direction as the normal ruled line on the normal ruled line;
The perforation forming step is a method for forming a perforation of a corrugated cardboard sheet, in which the perforation is formed after the normal ruled line is formed.

  In this way, since the perforation is formed on the normal ruled line after the normal ruled line is formed, the back liner is prevented from breaking along the perforated line due to the pressing force when forming the normal ruled line. Can do. That is, if a normal ruled line is formed on the perforation after the perforation is formed, the back liner may break along the perforation due to the pressing force when forming the normal ruled line. On the other hand, if the perforation is formed on the normal ruled line after forming the normal ruled line, the cardboard is in a state of being crushed by the normal ruled line before forming the perforated line, so that the back liner is not broken. It is possible to form a regular ruled line and a perforated line.

  Preferably, the perforation forming step forms the perforation after the reverse ruled line is formed.

  In this case, since the perforation is formed after the reverse ruled line is formed, the front liner can be prevented from breaking along the perforation due to the tension acting on the front liner when forming the reverse ruled line. . That is, if the reverse ruled line is formed after the perforation is formed, the front liner may break along the perforation due to the tension acting on the front liner when forming the reverse ruled line, When the perforation is formed after the reverse ruled line is formed, the reverse ruled line and the perforated line can be formed without breaking the front liner.

Moreover, in this invention, the perforation formation unit of the following structures is provided as a perforation formation unit suitable for manufacture of the cardboard sheet | seat which forms the said cardboard box.
A normal ruled ring that forms a groove-like normal ruled line with a recessed side of the back liner, on a cardboard sheet having a front liner, a back liner, and a core provided between the front liner and the back liner; A ruled line forming device for forming the normal ruled line and the reverse ruled line so as to extend in parallel with each other with a reverse ruled line forming a groove-like reverse ruled line recessed on the front liner side;
A perforation forming device for forming a perforation extending in the same direction as the normal ruled line on the normal ruled line;
The perforation forming apparatus is a corrugated sheet perforation forming unit having a round perforation forming knife downstream of the normal ruled line ring so as to form the perforation after the normal ruled line is formed.

  In this way, after forming the normal ruled line with the normal ruled line ring, the perforation is formed with the perforation forming knife arranged on the downstream side of the normal ruled line ring. It is possible to prevent the liner from breaking along the perforation. In other words, if the perforation forming knife is arranged upstream of the normal crease ring, after forming the perforation with the perforation forming knife, the normal crease line is formed on the perforation with the normal crease ring. The back liner may break along the perforation due to the pressing force when forming the normal ruled line, but if the perforation forming knife is placed downstream of the normal ruled ring, the back liner will break. It is possible to form a regular ruled line and a perforation without overlapping.

  The perforation forming knife is preferably disposed downstream of the reverse ruled line ring so as to form the perforation after the reverse ruled line is formed.

  In this case, after the reverse crease line is formed by the reverse crease line, the perforation is formed by the perforation forming knife arranged on the downstream side of the reverse crease line, so that it acts on the front liner when forming the reverse crease line. The tension can prevent the front liner from breaking along the perforations. That is, if the perforation forming knife is arranged on the upstream side of the reverse crease ring, the reverse crease line is formed after forming the perforation with the perforation formation knife, so the reverse crease line is formed. Sometimes the front liner may break along the perforation due to the tension acting on the front liner, but if the perforation forming knife is placed downstream of the reverse crease ring, the front liner will not break It is possible to form reverse ruled lines and perforations.

  The sewing machine forming unit adopts, for example, one provided in the middle of a corrugating machine that manufactures a corrugated cardboard sheet, or one provided as a part of a cutting machine that cuts a sheet of corrugated cardboard manufactured by the corrugating machine. Can do.

Here, as the sewing machine forming unit provided in the middle of the corrugating machine for manufacturing the corrugated cardboard sheet, for example, one having the following configuration can be adopted.
The ruled line forming device is a scorer that forms the normal ruled line on a corrugated cardboard sheet that is continuous in a strip shape in the middle of a corrugating machine, and the scorer has the normal ruled line ring and the reverse ruled line ring,
The perforation forming device is attached to the scorer.

Moreover, as what was provided as a part of the cutting machine which cuts the corrugated machine of the sheet | seat corrugated sheet, the thing of the following structures is employable, for example.
The ruled line forming device is a cutting machine for cutting a sheet of corrugated cardboard sheets into a predetermined width dimension, and the cutting machine has the normal ruled line ring and the reverse ruled line ring,
The perforation forming device is attached to the cutting machine.

  In the cardboard box according to the present invention, the normal ruled line and the perforation are formed between the flap and the peripheral wall so that the flap can be smoothly cut along the normal ruled line and the perforated line. In addition, a groove-like reverse ruled line with a recessed front liner is formed at a position spaced from the normal ruled line on the flap side, so that when the flap is folded outside the peripheral wall, the flap It does not break at the regular ruled line in which the eye is formed, but it breaks along the reverse ruled line without the perforation. Therefore, when boxing goods, it can prevent that a crack arises along the perforation between a flap and a peripheral wall.

The figure which looked at the blank of the cardboard box of this embodiment from the front liner side Enlarged view of the normal ruled line between the upper flap of the blank and the side plate shown in FIG. Enlarged cross-sectional view along line III-III in FIG. The expanded sectional view which shows the state which bent the upper flap shown in FIG. 3 to the back liner side Enlarged sectional view along line V-V in FIG. FIG. 3 is an enlarged cross-sectional view showing a state in which the upper flap shown in FIG. 3 is bent to the front liner side. FIG. 3 is an enlarged cross-sectional view showing a state in which the upper flap is bent to the front liner side when the reverse ruled line shown in FIG. 3 is not provided. The perspective view which shows the cardboard box of the state before assembling the blank shown in FIG. 1 and folding an upper flap The perspective view which shows the state which folded the upper flap shown in FIG. 8 to the outer side of the surrounding wall, and inserted the goods in the cardboard box. The perspective view which shows the process of folding the upper flap shown in FIG. 9 inside a surrounding wall. The perspective view which shows the state which closed the upper end opening of the surrounding wall with the upper flap shown in FIG. 10, and sealed the cardboard box The perspective view which shows the state which opened the cardboard box shown in FIG. Sectional drawing which shows the part of the slitter scorer and perforation forming apparatus of a corrugating machine suitable for manufacture of the corrugated cardboard sheet | seat which forms the blank shown in FIG. The expanded sectional view of the vicinity of the perforation forming knife of the perforation forming apparatus shown in FIG. The top view which shows typically an example of arrangement | positioning of the reverse ruled line ring, the normal ruled line ring, the slitter knife, and the perforation forming knife shown in FIG. Sectional drawing which shows the example which has arrange | positioned the reverse ruled line ring shown in FIG. 13 coaxially with a normal ruled line ring or a ruled line ring The top view which shows typically an example of arrangement | positioning of the reverse ruled line ring, normal ruled line ring, slitter knife, and perforation forming knife shown in FIG. The top view which shows typically the example using the special ruled line ring which integrated the reverse ruled line ring and the normal ruled line ring shown in FIG. The partial expanded sectional view which shows typically the shape of the special ruled line ring shown in FIG. Sectional drawing which shows the perforation forming unit for sheet | seat corrugated cardboard sheets

  FIG. 1 shows a blank of a cardboard box according to an embodiment of the present invention. The blank is formed of corrugated cardboard having a front liner 1, a back liner 2, and a core 3 provided between the front liner 1 and the back liner 2. This blank has square side plates 5, 6, 7, 8 that are arranged in series via ruled lines 4. The ruled line 4 extends in a direction parallel to the corrugated cardboard. A joint allowance 10 is connected to the side edge of the side plate 5 located at the end via a ruled line 9. The side plates 5, 6, 7, and 8 are portions that constitute the peripheral wall 31 (see FIG. 8) when the cardboard box 30 is assembled.

  Upper flaps 11, 12, 13, and 14 are connected to upper edges of the side plates 5, 6, 7, and 8, respectively. Between the side plates 5, 6, 7, 8 and the upper flaps 11, 12, 13, 14, normal ruled lines 15 are formed for folding the upper flaps 11, 12, 13, 14 inside the box. Usually, the ruled line 15 extends in a direction perpendicular to the corrugated cardboard. Further, between the side plates 5, 6, 7, 8 and the upper flaps 11, 12, 13, 14, a perforation 16 for separating the flaps is formed on the normal ruled line 15.

  A reverse ruled line 17 for folding the upper flaps 11, 12, 13, and 14 outward is formed at the end of each upper flap 11, 12, 13, and 14 on the base side (that is, the side close to the normal ruled line 15). Yes. The reverse ruled lines 17 are arranged in parallel to the normal ruled lines 15 at intervals on the upper flaps 11, 12, 13, and 14 side. The reverse ruled line 17 extends in a direction perpendicular to the corrugated cardboard. Between the adjacent upper flaps 11, 12, 13, 14, a cut groove 18 parallel to the step is provided, and the upper flaps 11, 12, 13, 14 are separated from each other through the cut groove 18. It has become.

  The side plates 6 and 8 are formed with a breaking line 19 for assisting in opening. The break line 19 is formed so that the center portion thereof is positioned below the perforation 16 and both end portions thereof are connected to the perforation 16. In the figure, the central portion of the breaking line 19 is constituted by a continuous cutting line, and both end portions of the breaking line 19 are constituted by intermittent cutting lines. In the side plates 6 and 8, a handle hole 20 is formed outside the region surrounded by the perforation 16 and the break line 19.

  Lower flaps 21, 22, 23, and 24 are connected to the lower edges of the side plates 5, 6, 7, and 8, respectively. Between the side plates 5, 6, 7, 8 and the lower flaps 21, 22, 23, 24, ruled lines 25 are formed for folding the lower flaps 21, 22, 23, 24 inward. The ruled line 25 extends in a direction perpendicular to the corrugated cardboard. Between the adjacent lower flaps 21, 22, 23, 24, a cut groove 26 parallel to the step is provided, and the lower flaps 21, 22, 23, 24 are separated from each other through the cut groove 26. It has become.

  As shown in FIGS. 2 and 3, the normal ruled line 15 is formed in a groove shape in which the side of the back liner 2 is recessed. As shown in FIG. 4, the upper flaps 11, 12, 13, 14 are formed along the normal ruled line 15. Can be folded to the back liner 2 side. As shown in FIG. 3, the perforation 16 is formed at a position corresponding to the groove bottom of the normal ruled line 15. On the other hand, the reverse ruled line 17 is formed in a groove shape in which the side of the front liner 1 is recessed, and the upper flaps 11, 12, 13, and 14 are folded along the reverse ruled line 17 to the side of the front liner 1 as shown in FIG. Be able to.

As shown in FIG. 3, the depth A ₂ of the reverse ruled line 17 is set to be equal to or deeper than the depth A ₁ of the normal ruled line 15. Further, the reverse ruled lines 17 are arranged so that the interval B between the center of the normal ruled lines 15 and the center of the reverse ruled lines 17 is 5 mm or more and 20 mm or less. Here, the center of the normal ruled line 15 is the most recessed position from the surface of the back liner 2, and the center of the reverse ruled line 17 is the most recessed position from the surface of the front liner 1.

  As shown in FIG. 2, the perforation 16 includes a large number of cuts 27 arranged in a straight line at a predetermined interval. Each cut 27 is formed in a straight line parallel to the normal ruled line 15, and the cuts 27 are arranged on a straight line parallel to the normal ruled line 15. Each cut 27 has the same length.

  As shown in FIG. 5, each cut 27 is formed through the front liner 1, the core 3, and the back liner 2. Here, each notch 27a of the front liner 1 is formed at a position coinciding with each notch 27b of the back liner 2, and the length of each notch 27a of the front liner 1 is the length of each notch 27b of the back liner 2. Shorter than that. As a result, the length of the connecting portion between the adjacent cuts 27 a of the front liner 1 is longer than the length of the connecting portion between the adjacent cuts 27 b of the back liner 2. Further, the width of each cut 27 a of the front liner 1 (that is, the width dimension in the direction orthogonal to the direction in which the perforation 16 extends) is narrower than the width of each cut 27 b of the back liner 2.

  The interval between adjacent cuts 27a of the front liner 1 (that is, the length of the connecting portion between the adjacent cuts 27a of the front liner 1) is 2 mm or more and 4 mm or less (preferably 2.5 mm or more and 3.5 mm or less). ing. When the upper flaps 11, 12, 13, and 14 (see FIG. 1) are bent at a right angle along the perforations 16 so that the front liner 1 is on the outside, assuming that the length is 2 mm or more (preferably 2.5 mm or more) The situation where the front liner 1 breaks along the perforation 16 due to the tension acting on the front liner 1 can be prevented. On the other hand, if it is 4 mm or less (preferably 3.5 mm or less), the fracture surface when the upper flaps 11, 12, 13, 14 are cut along the perforations 16 as shown in FIG.

As shown in FIG. 5, the ratio of the length _{L 1} of each notch 27b of the back liner 2, the length _{L 2} of the joint portion between the cuts 27b adjacent the back liner 2, 2: 1 to 4: A range of 1 is set. Here, the length _{L 2} of the joint portion between the cuts 27b adjacent the back liner 2, 2 mm or more 4mm or less (preferably 2.5mm or more, 3.5 mm or less).

  The blank shown in FIG. 1 can be assembled as follows, for example.

  As shown in FIG. 8, the side plates 5, 6, 7 and 8 are bent into a cylindrical shape along the ruled line 4 so that the back liner 2 is inside, and the joint 10 connected to the side plate 5 at one end is connected to the other end. Are adhered to the inner surface of the side plate 8, and the peripheral wall 31 is formed by these side plates 5, 6, 7, 8. Next, the lower flaps 22, 24 connected to the lower ends of the side plates 6, 8 corresponding to the width surface of the cardboard box 30 are bent along the ruled line 25 inside the peripheral wall 31, and then the length surface of the cardboard box 30. The lower flaps 21, 23 connected to the lower ends of the side plates 5, 7 are bent inside the peripheral wall 31 along the ruled line 25, and the lower flaps 21, 22, 23, 24 are used to open the lower end opening of the peripheral wall 31. A closed bottom 32 is formed. In the drawing, the interval between the reverse ruled line 17 and the normal ruled line 15 (interval B in FIG. 3) is exaggerated and shown larger than the actual one.

  Next, the product is boxed. At this time, as shown in FIG. 8, it is possible to insert the product into the cardboard box 30 with the upper flaps 11, 12, 13, and 14 extending straight above the peripheral wall 31. When inserting a product by work, in the state shown in FIG. 8, it is difficult to insert the product because the upper flaps 11, 12, 13, and 14 are obstructive.

  Therefore, in order to facilitate insertion of the product into the cardboard box 30, the upper flaps 11, 12, 13, and 14 are folded outside the peripheral wall 31 (so-called reverse folding) as shown in FIG. Here, as shown in FIG. 3, the normal ruled line 15 is formed in a groove shape in which the back liner 2 side is recessed, so that the upper flaps 11, 12, 13, 14 are connected to the back liner 2 along the normal ruled line 15. When folding to the side, it is possible to fold with a relatively small force, but conversely, in order to fold the upper flaps 11, 12, 13, 14 along the ruled line 15 to the side of the front liner 1, It has the characteristic that a large force is required. On the other hand, since the reverse ruled line 17 has a groove shape with the front liner 1 side recessed, when the upper flaps 11, 12, 13, 14 are folded along the reverse ruled line 17 to the front liner 1 side, Although it can be folded with a small force, it has a characteristic that a relatively large force is required to fold the upper flaps 11, 12, 13, 14 to the side of the back liner 2 along the reverse ruled line 17. .

  Therefore, as shown in FIGS. 6 and 9, when the upper flaps 11, 12, 13, and 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, and 14 are not folded at the regular ruled line 15, and are reversed. It will be broken along the ruled line 17. Here, if there is no reverse ruled line 17, when the upper flaps 11, 12, 13, 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, 14 are normal ruled lines as shown in FIG. 15, and the tension acting on the back liner 2 side may cause a crack between the upper flaps 11, 12, 13, 14 and the peripheral wall 31 along the perforation 16. On the other hand, the corrugated cardboard box 30 of this embodiment forms the reverse ruled line 17 at a position spaced from the normal ruled line 15 on the side of the upper flaps 11, 12, 13, 14, and thereby the upper flap 11, When the 12, 13, 14 is folded along the regular ruled line 15 to the outside of the peripheral wall 31, the upper flaps 11, 12, 13, 14 are prevented from being folded at the regular ruled line 15, and the perforation 16 is prevented from cracking. ing. Although FIG. 9 shows an example in which the upper flaps 11, 12, 13, and 14 are all folded, only one of the upper flaps 11, 12, 13, and 14 (for example, as viewed from a boxing operator). You may make it fold the thing on the near side.

  Thereafter, as shown in FIGS. 10 and 11, the upper flaps 12 and 14 are bent along the normal ruled line 15 to the inside of the peripheral wall 31, and the upper flaps 11 and 13 are bent along the normal ruled line 15 to the inside of the peripheral wall 31. Here, when the upper flaps 11, 12, 13, and 14 are folded inside the peripheral wall 31 (forward fold), the upper flaps 11, 12, 13, and 14 are Instead of being folded along the reverse ruled line 17, it is folded along the normal ruled line 15 (see FIG. 4). Subsequently, the tops of the upper flaps 11 and 13 are joined together with an adhesive tape 34 to form the lid 33. The lid 33 may be formed by fixing upper and lower portions of the upper flaps 11 and 13 and the upper flaps 12 and 14 with an adhesive such as hot melt or a stapler for cardboard.

  By the way, as shown in FIG. 11, in a state where the upper flaps 11, 12, 13, and 14 are folded inside the peripheral wall 31, the reverse ruled line 17 is positioned not on the peripheral wall 31 extending vertically but on the lid 33. For this reason, there is almost no reduction in the compressive strength of the cardboard box 30 (particularly, the durability when the upper and lower compressive loads are applied to the cardboard box 30) due to the provision of the reverse ruled lines 17.

  The cardboard box 30 assembled in this way can be opened as follows, for example.

  The opening assisting breaking line 19 formed on the side plates 6 and 8 shown in FIG. 11 is broken and a finger is inserted, and the upper flaps 12 and 14 are pulled upward. As a result, as shown in FIG. 12, the upper flaps 12 and 14 are separated from the side plates 6 and 8 along the normal ruled lines 15 and the perforations 16. Since the upper flaps 11 and 13 are also lifted upward together with the upper flaps 12 and 14, the upper flaps 11 and 13 are also separated from the side plates 5 and 7 along the normal ruled line 15 and the perforation 16. In this manner, the cardboard box 30 can be opened by smoothly separating the lid 33 formed of the upper flaps 11, 12, 13, and 14 from the peripheral wall 31 without using a cutter such as a cutter. Also, as shown in FIG. 12, when the upper flaps 11, 12, 13, and 14 are separated from the peripheral wall 31 and the cardboard box 30 is opened, the product 35 accommodated in the cardboard box 30 is transferred to the upper flaps 11, 12, 13, and 14. Therefore, the product 35 can be exhibited at the store while being stored in the cardboard box 30.

  Since the above-described corrugated cardboard box 30 is formed by overlapping the normal ruled lines 15 and the perforations 16, the upper flaps 11, 12, 13, and 14 can be smoothly separated along the normal ruled lines 15 and the perforations 16. Therefore, the opening workability of the cardboard box 30 is excellent.

  Further, when the upper flaps 11, 12, 13, and 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, and 14 are folded at the normal ruled line 15 in which the perforation 16 is formed. Instead, it breaks along the reverse ruled line 17 without the perforation 16. Therefore, it is possible to prevent cracks from occurring along the perforations 16 between the upper flaps 11, 12, 13, 14 and the peripheral wall 31 when the product 35 is boxed.

Further, since the depth A ₂ (see FIG. 3) of the reverse ruled line 17 is set to be the same as or deeper than the depth A ₁ of the normal ruled line 15 in the cardboard box 30, the upper flaps 11, 12, The upper flaps 11, 12, 13, 14 are prevented from being folded along the normal ruled line 15 when the 13, 14 is folded to the outside of the peripheral wall 31, so that the upper flap 11, 14, 14 can be more reliably folded along the reverse ruled line 17. Is possible.

  Further, the cardboard box 30 has an interval B (see FIG. 3) between the center of the normal ruled line 15 and the center of the reverse ruled line 17 of 5 mm or more, so the upper flaps 11, 12, 13, and 14 are folded outside the peripheral wall 31. It is possible to prevent the normal ruled line 15 and the reverse ruled line 17 from being broken at the same time. Further, since the interval B between the center of the normal ruled line 15 and the center of the reverse ruled line 17 is 20 mm or less, when the upper flaps 11, 12, 13, 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, It is possible to effectively prevent 14 from being bent along the normal ruled line 15 without being broken at the reverse ruled line 17.

  The corrugated cardboard box 30 has a perforation so that the length of the connecting portion between the adjacent cuts 27a of the front liner 1 is longer than the length of the connecting portion between the adjacent cuts 27b of the back liner 2. 16 is formed, the front liner 1 is not easily cracked when the upper flaps 11, 12, 13, 14 are bent inside the peripheral wall 31 when the cardboard box 30 is assembled.

By setting the depth A ₂ (see FIG. 3) of the reverse ruled line 17 to be equal to or deeper than the depth A ₁ of the normal ruled line 15, the upper flap 11 is folded to the outside of the peripheral wall 31. In order to confirm that the flap 11 can be prevented from being folded along the regular ruled line 15, a sample of a cardboard box of A ₁ > A ₂ , a sample of a cardboard box of A ₁ = A _{2, and} a cardboard box of A ₁ <A ₂ When five samples are prepared for each material, and the upper flap 11 of each sample is bent to the outside of the peripheral wall 31, whether the upper flap 11 folds along the regular ruled line 15 or the reverse ruled line 17 A test was conducted to investigate. The test results are shown in the following table.

The meanings of “◯”, “Δ”, and “×” in the above table are as follows.
“◯”: Out of 5 samples, the upper flaps of all the samples were broken only by the reverse ruled line.
“Δ”: The upper flaps of 3 to 4 samples out of 5 were folded only by the reverse ruled line, but the remaining samples were folded only by the normal ruled line or both the reverse ruled line and the normal ruled line.
“X”: The upper flaps of 0 to 2 samples out of 5 were folded only by the reverse ruled line, but the remaining samples were folded only by the normal ruled line or both the reverse ruled line and the normal ruled line.

Based on the above test results, the depth A ₂ of the reverse ruled line 17 is set to be the same as the depth A ₁ of the normal ruled line 15, or preferably the depth A ₂ of the reverse ruled line 17 is greater than the depth A _{1 of the} normal ruled line 15. It can be seen that the upper flap 11 can be prevented from being folded along the normal ruled line 15 when the upper flap 11 is folded outside the peripheral wall 31 by setting the depth further deep.

  Further, by setting the interval B between the center of the normal ruled line 15 and the center of the reverse ruled line 17 to 5 mm or more and 20 mm or less, the reverse ruled line functions more effectively when the upper flap 11 is folded outside the peripheral wall 31. In order to confirm this, when five samples of corrugated cardboard boxes each having a different interval B are prepared and the upper flap 11 of each sample is bent to the outside of the peripheral wall 31, the upper flap 11 is A test was conducted to investigate which of the ruled line 15 and the reverse ruled line 17 folds along the ruled line. The test results are shown in the following table.

The meanings of “◯”, “Δ”, and “×” in the above table are as follows.
“◯”: Out of 5 samples, the upper flaps of all the samples were broken only by the reverse ruled line.
“Δ”: The upper flaps of 3 to 4 samples out of 5 were folded only by the reverse ruled line, but the remaining samples were folded only by the normal ruled line or both the reverse ruled line and the normal ruled line.
“X”: The upper flaps of 0 to 2 samples out of 5 were folded only by the reverse ruled line, but the remaining samples were folded only by the normal ruled line or both the reverse ruled line and the normal ruled line.

  According to the above test results, when the interval B between the center of the normal ruled line 15 and the center of the reverse ruled line 17 is set to 5 mm or more and 20 mm or less (more preferably 5 mm or more and 10 mm or less), the upper flap 11 is placed outside the peripheral wall 31. It can be seen that the reverse ruled line functions more effectively when folded.

  Next, a corrugating machine suitable for manufacturing a corrugated cardboard sheet forming the corrugated cardboard box 30 of the above embodiment will be described. The corrugating machine includes, in order from the upstream side to the downstream side, a single facer (not shown), a double facer (not shown), a slitter scorer 40 (see FIG. 13), a perforation forming device 41 (see FIG. 13), Has a cut-off (not shown). The single facer is a device that forms a single-sided cardboard by forming a core 3 into a corrugated shape and bonding a back liner 2 to the core 3. The double facer is an apparatus for making a double-sided cardboard (hereinafter referred to as “corrugated cardboard sheet”) by bonding the front liner 1 to a single-sided cardboard fed from a single facer. Cut-off is a device that cuts a strip-like corrugated cardboard sheet continuous in the transport direction into a sheet by cutting it in a direction perpendicular to the transport direction. In the corrugating machine, the corrugated cardboard sheet is conveyed in such a direction that the front liner 1 is on the lower side and the back liner 2 is on the upper side.

  As shown in FIG. 13, the slitter scorer 40 includes a scorer 42 and a slitter 43.

  The scorer 42 includes an upper first rotation shaft 45 and a second rotation shaft 46 disposed on the upper side of the cardboard sheet 44, and a lower first rotation shaft 47 and a second rotation disposed on the lower side of the cardboard sheet 44. An axis 48, an upper ruled ring 49 fixed to the upper first rotating shaft 45, a lower ruled ring 50 fixed to the lower first rotating shaft 47, and an upper second rotating shaft 46. It has a fixed upper regular ruled ring 51 and a lower regular ruled ring 52 fixed to the lower second rotation shaft 48. The upper first rotating shaft 45 and the lower first rotating shaft 47 are arranged to face each other in the vertical direction. Further, the upper second rotating shaft 46 and the lower second rotating shaft 48 are also arranged to face each other in the vertical direction. The upper second rotating shaft 46 and the lower second rotating shaft 48 are disposed adjacent to the downstream side of the upper first rotating shaft 45 and the lower first rotating shaft 47.

  On the outer periphery of the upper ruled line ring 49, a convex portion 53 that is continuous in the circumferential direction is provided over the entire circumference. On the outer periphery of the lower ruled ring 50, a recess 54 is provided continuously in the circumferential direction over the entire circumference. Similarly, on the outer periphery of the upper normal ruled ring 51, a convex portion 55 that is continuous in the circumferential direction is provided over the entire circumference. In addition, a concave portion 56 that is continuous in the circumferential direction is provided on the outer periphery of the lower normal ruled ring 52.

  The scorer 42 sandwiches the cardboard sheet 44 between the convex portion 53 on the outer periphery of the upper crease ring 49 and the concave portion 54 on the outer periphery of the lower crease ring 50, so that the ruled line 15 extending in the transport direction is formed on the corrugated cardboard sheet 44. To form. Similarly, the scorer 42 sandwiches the corrugated cardboard sheet 44 between the convex portion 55 on the outer periphery of the upper normal crease ring 51 and the concave portion 56 on the outer periphery of the lower normal crease ring 52, so A normal ruled line 15 extending in a direction perpendicular to the eyes is formed on the cardboard sheet 44.

  The scorer 42 has a reverse ruled line forming unit 57. The reverse ruled line forming portion 57 is fixed to the upper rotating shaft 58 disposed above the corrugated cardboard sheet 44, the lower rotating shaft 59 disposed below the corrugated cardboard sheet 44, and the upper rotating shaft 58. It has an upper reverse ruled line ring 60 and a lower reverse ruled line ring 61 fixed to the lower rotating shaft 59. The upper rotating shaft 58 and the lower rotating shaft 59 are arranged to face each other in the vertical direction. On the outer periphery of the upper reverse crease ring 60, a concave portion 62 that is continuous in the circumferential direction is provided on the entire circumference, and on the outer periphery of the lower reverse crease line ring 61, a convex portion 63 that is continuous in the circumferential direction is provided on the entire periphery. Is provided. The reverse ruled line forming unit 57 sandwiches the corrugated cardboard sheet 44 between the concave portion 62 on the outer periphery of the upper reverse ruled line ring 60 and the convex portion 63 of the lower reverse ruled line ring 61, so that the conveyance direction (that is, the step) A reverse ruled line 17 extending in a direction perpendicular to the cardboard sheet 44 is formed.

  In addition, the reverse ruled line forming unit 57 includes an elevating drive device 64 for the upper reverse ruled line ring 60. When the reverse ruled line 17 is not formed on the cardboard sheet 44, the lifting drive unit 64 raises the upper reverse ruled line ring 60. When the reverse ruled line 17 is formed on the cardboard sheet 44, the lift drive unit 64 is moved upward. The ring 60 is lowered.

  The slitter 43 includes rotating shafts 65 and 66 disposed above and below the corrugated cardboard sheet 44, a knife receiver 67 fixed to the upper rotating shaft 65, and a slitter knife 68 fixed to the lower rotating shaft 66. . On the outer periphery of the slitter knife 68, a continuous cutting edge is formed on the entire circumference in the circumferential direction. The slitter knife 68 is a rotary blade that cuts into the cardboard sheet 44 from the lower side (that is, the front liner 1 side) and cuts the cardboard sheet 44 along the conveying direction (that is, the direction perpendicular to the step).

  The slitter scorer 40 includes a frame 70 that supports the upper rotary shafts 45 and 46 and the lower rotary shafts 47 and 48, a base member 71 fixed to the floor F, and the frame 70 and the base member 71. And a linear guide 72 provided therebetween. The linear guide 72 supports the frame 70 so as to be movable in a horizontal direction perpendicular to the conveying direction of the corrugated cardboard sheet 44. Further, when the position of the corrugated cardboard sheet 44 passing through the slitter scorer 40 is changed in a direction orthogonal to the conveying direction, a frame moving device 73 that moves the frame 70 following the change in the position of the corrugated cardboard sheet 44 is provided. Is attached.

  The reverse ruled line forming portion 57 includes an auxiliary frame 74 that supports the upper rotating shaft 58 and the lower rotating shaft 59, a base member 75 fixed to the floor surface F, and between the auxiliary frame 74 and the base member 75. And a linear guide 76 provided. The linear guide 76 supports the auxiliary frame 74 so as to be movable in a horizontal direction perpendicular to the conveying direction of the cardboard sheet 44. The auxiliary frame 74 is provided with a connection bracket 77 connected to the frame 70 of the slitter scorer 40. By connecting the frame 70 and the auxiliary frame 74 to each other via the connection bracket 77, when the frame moving device 73 moves the frame 70 of the slitter scorer 40, the auxiliary frame 74 also moves together with the frame 70. It is like that.

  The perforation forming device 41 is disposed on the downstream side of the scorer 42. The perforation forming device 41 includes rotary shafts 80, 81 arranged above and below the corrugated cardboard sheet 44, a round perforation forming knife 82 fixed to the upper rotary shaft 80, and a lower rotary shaft 81. And a fixed knife receiver 83. The perforation forming knife 82 is a rotary blade that cuts into the cardboard sheet 44 from the upper side (that is, the back liner 2 side) and forms the perforation 16 (see FIG. 14) in the cardboard sheet 44. The perforation forming knife 82 and the normal ruled line rings 51 and 52 extend in the conveying direction of the corrugated cardboard sheet 44 so that the perforation 16 is formed on the normal ruled line 15 formed by the normal ruled line rings 51 and 52. They are arranged on the same straight line.

  The perforation forming device 41 includes a frame 84 that supports the rotation shafts 80 and 81, a base member 85 that is fixed to the floor surface F, and a linear guide 86 that is provided between the frame 84 and the base member 85. Have. The linear guide 86 supports the frame 84 so as to be movable in a horizontal direction perpendicular to the conveying direction of the cardboard sheet 44. The frame 84 is provided with a connection bracket 87 that is connected to the frame 70 of the slitter scorer 40. By connecting the frame 84 and the frame 70 to each other via the connecting bracket 87, when the frame moving device 73 moves the frame 70 of the slitter scorer 40, the frame 70 of the perforation forming device 41 is integrated with the frame 70. 84 also moves.

  In addition, the perforation forming device 41 has an elevating drive device 88 for the perforation forming knife 82. When the perforation 16 is not formed on the cardboard sheet 44, the lifting drive 88 raises the perforation forming knife 82, and when the perforation 16 is formed on the cardboard sheet 44, the lifting drive 88 is used by the perforation forming knife 82. Is lowered.

  As shown in FIG. 14, on the outer periphery of the perforation forming knife 82, a plurality of blade portions 89 protruding outward in the radial direction are formed at intervals in the circumferential direction. Each blade portion 89 has a shape in which the width dimension in the circumferential direction gradually decreases from the inside in the radial direction toward the outside. Therefore, when the perforation 16 is formed in the corrugated cardboard sheet 44 by the perforation forming knife 82, the length of the connecting portion between the adjacent cuts 27a of the front liner 1 is equal to that of the back liner 2 as shown in FIG. It becomes longer than the length of the connecting portion between the adjacent cuts 27b. The outer edge in the radial direction of each blade portion 89 has an arc shape having a center at the same position as the center of the rotation shaft 80.

  When the corrugated machine 44 is manufactured by the above corrugated machine, as shown in FIG. 15, after forming the normal ruled line 15 with the normal ruled line rings 51 and 52, the perforation formed on the downstream side of the normal ruled line rings 51 and 52 is formed. Since the perforation 16 is formed by the knife 82, it is possible to prevent the back liner 2 from being broken along the perforation 16 by the pressing force when the normal ruled line 15 is formed. That is, if the perforation forming knife 82 is arranged upstream of the normal ruled line rings 51, 52, the perforation forming knife 82 forms the perforation 16, and then the normal ruled line rings 51, 52 on the perforated line 16. Therefore, the back liner 2 may be broken along the perforation 16 due to the pressing force when forming the normal ruled line 15. If the perforation forming knife 82 is arranged on the downstream side of the normal ruled line rings 51 and 52 as described above, the normal ruled line 15 and the perforated line 16 can be formed to overlap without breaking the back liner 2.

  Further, when the corrugated machine 44 is manufactured by the corrugating machine described above, the reverse ruled line 17 is formed by the reverse ruled line rings 60 and 61, and then the perforation is formed by the perforation forming knife 82 disposed on the downstream side of the reverse ruled line rings 60 and 61. 16 is formed, it is possible to prevent the front liner 1 from breaking along the perforation 16 due to the tension acting on the front liner 1 when forming the reverse ruled line 17. That is, if the perforation forming knife 82 is disposed upstream of the reverse ruled line rings 60 and 61, the reverse ruled line 17 is formed by the reverse ruled line rings 60 and 61 after the perforated line forming knife 82 forms the perforated line 16. Therefore, the tension applied to the front liner 1 when the reverse ruled line 17 is formed may cause the front liner 1 to break along the perforation 16, whereas the corrugating machine described above. If the perforation forming knife 82 is arranged on the downstream side of the reverse ruled line rings 60 and 61, the reverse ruled line 17 and the perforated line 16 can be formed without breaking the front liner 1.

  When the auxiliary frame 74 of the reverse ruled line forming unit 57 is formed separately from the frame 70 of the slitter scorer 40 as in the above embodiment, the reverse ruled line forming unit 57 is introduced by modifying the existing slitter scorer 40. However, when a new slitter scorer is introduced into the corrugating machine, the auxiliary frame 74 of the reverse ruled line forming unit 57 and the frame 70 of the slitter scorer 40 can be shared by a single member. It is.

  In the above embodiment, the reverse ruled line forming unit 57 is described on the upstream side of the slitter scorer 40. However, the reverse ruled line forming unit 57 is arranged on the downstream side of the slitter scorer 40 and the perforation forming device 41. It is also possible to arrange it upstream.

  In the above embodiment, the upper reverse ruled line ring 60 and the lower reverse ruled line ring 61 are divided into upper and lower rotary shafts 45, 46, 47, 48 to which the ruled line rings 49, 50 and the normal ruled line rings 51, 52 are fixed. Although fixed to the separate rotating shafts 58 and 59, as shown in FIGS. 16 and 17, the upper reverse ruled line ring 60 and the lower reverse ruled line ring 61 are connected to the ruled line rings 49 and 50 and the normal ruled line rings 51 and 52, respectively. It is also possible to fix to the upper and lower rotary shafts 45, 46, 47, and 48 to which is fixed.

  Further, as shown in FIGS. 18 and 19, an upper special crease ring 90 in which an upper reverse crease ring 60 and an upper normal crease ring 51 are integrated, a lower reverse crease ring 61 and a lower normal crease ring 61. It is also possible to form the normal ruled line 15 and the reverse ruled line 17 with the lower special ruled line ring 91 integrated with the ruled line ring 52. The upper special crease ring 90 is provided with a recess 62 and a protrusion 55 corresponding to the protrusion 62 of the upper reverse crease ring 60 and the protrusion 55 of the upper normal ruled ring 51 adjacent to each other in the axial direction. The special ruled line ring 91 is provided with a convex part 63 corresponding to the concave part 56 of the lower reverse ruled line ring 61 and a concave part 56 of the lower normal ruled line ring 52 and a concave part 56 adjacent to each other in the axial direction. .

  In the above-described embodiment, an example in which the perforation forming device 41 is disposed on the downstream side of the slitter scorer 40 has been described. However, the perforation forming device 41 may be provided at other positions as long as it is downstream of the scorer 42. For example, it may be incorporated in the frame 70 of the slitter scorer 40. Further, it is also possible to configure the perforation forming device 41 by mounting a perforation forming knife 82 coaxially with the rotation shaft 65 on the upper side of the slitter 43.

  In the above embodiment, the ruled line forming process for forming the normal ruled line 15 and the reverse ruled line 17 and the perforated line forming process for forming the perforation 16 on the normal ruled line 15 after the ruled line forming process are performed. The corrugating machine was also used, but both of these processes, or only the latter process, were performed after the corrugating machine (for example, using a cutting machine, the sheet corrugated cardboard sheet 44 was divided into a plurality of sheets and a ruled line was formed. Or a step of forming a ruled line on the corrugated cardboard sheet 44 using a printer slotter and performing printing.

  Even in this case, it is possible to prevent liner cracking due to the pressing force when the normal ruled line 15 is formed. That is, if the normal ruled line 15 is formed on the perforation 16 after the perforation 16 is formed, the back liner 2 may break due to the pressing force when the normal ruled line 15 is formed. If the perforation 16 is formed on the normal ruled line 15 after the normal ruled line 15 is formed, the cardboard is already crushed by the normal ruled line 15 before the perforated line 16 is formed. It is possible to prevent cracking.

  In the above embodiment, the ruled line forming device for forming the normal ruled lines 15 and the reverse ruled lines 17 on the corrugated cardboard sheet 44, and the perforated line forming device 41 for forming the perforations 16 on the normal ruled lines 15 on the downstream side of the ruled line forming device, A scorer 42 for forming the normal ruled lines 15 and the reverse ruled lines 17 on a corrugated cardboard sheet 44 that is continuous in a strip shape in the middle of the corrugating machine, and a perforation forming disposed downstream of the scorer 42 of the corrugating machine. As shown in FIG. 20, as a perforation forming unit according to an embodiment of the present invention, a single sheet of corrugated cardboard sheet 44 manufactured by a corrugating machine is processed one by one. It is also possible to adopt one.

  FIG. 20 shows a perforation forming unit for sheet corrugated cardboard sheets. This perforation forming unit is, for example, a modification of a cutting machine that cuts a sheet of corrugated cardboard sheet 44 into a predetermined width. Hereinafter, parts corresponding to the perforation forming unit shown in FIG.

  On the upstream side of the upper reverse ruled line ring 60 and the lower reverse ruled line ring 61, a paper feed table 92 that supports the corrugated cardboard sheet 44 is provided. A paper discharge table 93 is provided on the downstream side of the perforation forming knife 82 and the knife receiver 83.

  An example of use of this perforation forming unit will be described. When the sheet corrugated sheet 44 supported by the sheet feeding table 92 is fed between the upper reverse crease ring 60 and the lower reverse crease ring 61, first, the reverse crease line 17 is applied to the cardboard sheet 44 (see FIG. 1). Next, the normal ruled line 15 is formed on the corrugated cardboard sheet 44 between the upper normal ruled ring 51 and the lower normal ruled ring 52, and then the perforation forming knife 82 is used to form a sewing machine on the normal ruled line 15. The eyes 16 are formed so as to overlap each other. Here, a slitter knife (not shown) is attached to the rotary shafts 46 and 48 so as to be aligned in the axial direction with the upper and lower normal ruled line rings 51 and 52, and the cardboard sheet 44 is cut into a predetermined width by the slitter knife. Good.

  In the above embodiment, the normal ruled line 15 between the upper flap 11 and the peripheral wall 31, the normal ruled line 15 between the upper flap 12 and the peripheral wall 31, the normal ruled line 15 between the upper flap 13 and the peripheral wall 31, Although the perforations 16 are formed in all positions of the normal ruled line 15 in the portion between the upper flap 14 and the peripheral wall 31, the perforations 16 may be formed only in any one of these portions.

  In the above-described embodiment, the perforation 16 including the cuts 27 parallel to the direction in which the normal ruled line 15 extends is described as an example. However, a number of cuts 27 in a direction inclined with respect to the direction in which the normal ruled line 15 extends are provided. It is also possible to employ perforations 16 that are arranged in the width of the regular ruled line 15 at intervals. In short, each cut 27 constituting the perforation 16 only needs to be within the width of the regular ruled line 15.

  Moreover, in the said embodiment, although the length of each upper flap 11,12,13,14 was mentioned and demonstrated as an example, what was called the cardboard box (what is called A-type cardboard box) of the same shape, (For example, a so-called cardboard box having an upper flap large enough to close the upper end opening of the peripheral wall with a single piece, and a plug inserted into the front end of the upper flap into the peripheral wall to form a lid) It can also be applied to B-type cardboard boxes.

  In the above embodiment, the corrugated cardboard box having the rectangular peripheral wall 31 has been described as an example. However, the present invention relates to a peripheral wall other than the square, such as a corrugated cardboard box having an octagonal peripheral wall (so-called corner-cut cardboard box). You may apply to the cardboard box which has. Further, the present invention may be applied to a cardboard box having a top flap at the upper end of the peripheral wall but not having a lower flap at the lower end of the peripheral wall (a so-called semi-A type cardboard box). It can also be used in the form of a two-piece covering a cardboard box of the type as a cover.

DESCRIPTION OF SYMBOLS 1 Front liner 2 Back liner 3 Core 11, 12, 13, 14 Upper flap 15 Normal ruled line 16 Perforation 17 Reverse ruled line 30 Cardboard box 31 Perimeter wall 41 Perforation forming device 42 Scorer 51, 52 Normal ruled line ring 60, 61 Reverse ruled line Ring 82 Perforation forming knife 90, 91 Special ruled ring A ₁ Normal ruled line depth A ₂ Reverse ruled line depth B Distance between center of normal ruled line and center of reverse ruled line

Claims (9)

The back liner (2) has a corrugated cardboard having a front liner (1), a back liner (2), and a core (3) provided between the front liner (1) and the back liner (2). A peripheral wall (31) formed by being bent into a cylindrical shape so as to be inside,
In a corrugated cardboard box having flaps (11, 12, 13, 14) connected to one end of the peripheral wall (31),
Between the flap (11, 12, 13, 14) and the peripheral wall (31), the back liner (2) so that the flap (11, 12, 13, 14) is folded inside the peripheral wall (31). A groove-like regular ruled line (15) having a recessed side is formed,
A perforation (16) for separating the flap (11, 12, 13, 14) is formed on the regular ruled line (15).
The flaps (11, 12, 13, 14) are parallel to the normal ruled line (15) at a position spaced from the normal ruled line (15) on the side of the flaps (11, 12, 13, 14). ) Is formed on the front liner (1) side so as to be folded outwardly of the peripheral wall (31), and a groove-like reverse ruled line (17) is formed. The depth of the reverse borders ₍₁₇₎ (A 2), the normal depth of the ruled line ₍₁₅₎ (A 1) equal to or cardboard box according it deep Claim 1 than.   The said reverse ruled line (17) is arrange | positioned so that the space | interval (B) of the center of the said normal ruled line (15) and the center of the said reverse ruled line (17) may be 5 mm or more and 20 mm or less. The cardboard box described. A cardboard sheet (44) having a front liner (1), a back liner (2), and a core (3) provided between the front liner (1) and the back liner (2), A groove-like normal ruled line (15) having a concave side of the liner (2) and a groove-like reverse ruled line (17) having a concave side of the front liner (1) are referred to as the normal ruled line (15) and the reverse ruled line ( 17) and a ruled line forming step that extends so as to extend in parallel with an interval between each other,
A perforation forming step of forming a perforation (16) extending in the same direction as the normal ruled line (15) on the normal ruled line (15);
The perforation forming step is a corrugated sheet perforation forming method for forming the perforation (16) after the regular ruled line (15) is formed.   The said perforation formation process is a perforation formation method of the corrugated board sheet | seat of Claim 4 which forms the said perforation (16) after the said reverse ruled line (17) is formed. A cardboard sheet (44) having a front liner (1), a back liner (2), and a core (3) provided between the front liner (1) and the back liner (2), A normal crease ring (51, 52, 90, 91) for forming a groove-like normal ruled line (15) having a concave side of the liner (2), and a groove-like reverse ruled line (17 having a concave side of the front liner (1)) A ruled line forming device (60, 61, 90, 91) for forming the normal ruled line (15) and the reverse ruled line (17) so as to extend in parallel with a distance from each other. 42)
A perforation forming device (41) for forming a perforation (16) extending in the same direction as the normal ruled line (15) on the normal ruled line (15);
The perforation forming device (41) is downstream of the normal ruled line ring (51, 52, 90, 91) so as to form the perforation (16) after the normal ruled line (15) is formed. A perforation unit for corrugated cardboard sheets having a round perforation forming knife (82).   The perforation forming knife (82) is located downstream of the reverse ruled line ring (60, 61, 90, 91) so as to form the perforated line (16) after the reverse ruled line (17) is formed. The perforation forming unit for corrugated cardboard sheets according to claim 6, wherein The ruled line forming device (42) is a scorer that forms the normal ruled line (15) on a corrugated cardboard sheet (44) continuous in a strip shape in the middle of a corrugating machine, and the scorer is the normal ruled line ring (51, 52, 90). , 91) and the reverse ruled line ring (60, 61, 90, 91),
The perforation forming unit according to claim 6 or 7, wherein the perforation forming device (41) is attached to the scorer. The ruled line forming device is a cutting machine that cuts a sheet of corrugated cardboard sheet (44) into a predetermined width, and the cutting machine includes the normal ruled line ring (51, 52, 90, 91) and the reverse ruled line ring ( 60, 61, 90, 91)
The perforation forming unit according to claim 6 or 7, wherein the perforation forming apparatus is attached to the cutting machine.

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