JP2017013897A - Cardboard box, ruled line forming method of cardboard sheet and ruled line forming device of cardboard sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cardboard box easily boxing an article and having the excellent butting accuracy of flaps.SOLUTION: A groove-shaped usual ruled line 15 whose rear liner 2 side is recessed is formed so that an upper flap 11 is folded to the inside of a peripheral wall 31 between the upper flap 11 of a cardboard box and a peripheral wall 31. A groove-shaped reverse ruled line 16 whose front liner 1 side is recessed so that the upper flap 11 is folded to the outside of the peripheral wall 31 and in parallel with the usual ruled line 15 is formed at an upper flap 11 side to the usual ruled line 15. A weak ruled line 24 whose rear liner 2 side is recessed so as to be in parallel with the reverse ruled line 16 is formed at the opposite side of the usual ruled line 15 sandwiching the reverse ruled line 16.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cardboard box, a ruled line forming method for cardboard sheets, and a ruled line forming apparatus for cardboard sheets.

  Generally, a cardboard box has a peripheral wall formed by bending a corrugated cardboard into a cylindrical shape, and a plurality of flaps connected to one end of the peripheral wall. A regular ruled line is formed between the flap and the peripheral wall, and the flap can be smoothly folded inside the peripheral wall along the normal ruled line. Here, the corrugated cardboard has a front liner, a back liner, and a core provided between both liners, and the normal ruled line between the flap and the peripheral wall is on the back liner side (that is, the inside of the box). It is formed in a recessed groove shape.

  When a product is packed in a cardboard box, the flap may be folded to the outside of the peripheral wall (so-called reverse folding) to facilitate 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 the flap is folded inside the box, the flap can be smoothly folded along the regular ruled line. When folding outside the box, the flaps are difficult to break. Therefore, after folding the flap to the outside of the box, you must hold the flap by hand so that the flap does not return elastically, or fold the flap completely outside the box so that the flap does not return In such a case, there is a problem that the back liner of the cardboard is broken along the ruled line (so-called liner cracking).

  In order to solve such a problem, a cardboard box of Patent Document 1 has been proposed. In the corrugated cardboard box of Patent Document 1, reverse ruled lines are formed in parallel to the normal ruled lines at the base of the flap. The reverse ruled line is a groove-like ruled line that is recessed on the front liner side (that is, outside the box). When this reverse ruled line is provided, when the flap is folded to the outside of the peripheral wall, the flap is smoothly folded along the reverse ruled line, so that the product can be easily boxed.

Japanese Utility Model Publication No. 60-123317

  However, when the reverse ruled line described in Patent Document 1 is provided, it has been found that there is a possibility that the accuracy of butting the flap when the box is sealed may be lowered.

  That is, if the normal ruled line with the back liner side recessed and the reverse ruled line with the front liner side recessed are formed close to each other, the thickness of the corrugated board between the normal ruled line and the reverse ruled line becomes thin. Therefore, when the flap is folded outside the box, the corrugated cardboard may not be folded accurately at the center of the reverse ruled line, and may be folded between the normal ruled line and the reverse ruled line. Once the flap is folded between the normal ruled line and the reverse ruled line, the strength of the portion between the normal ruled line and the reverse ruled line decreases, so that when the flap is folded inside the box, the flap is centered on the normal ruled line. In this case, the line is broken again between the normal ruled line and the reverse ruled line again without being broken accurately. As a result, after folding the flap outside the box and inserting the product into the box, when the flap is folded inside the box and the box is sealed, there is a possibility that a gap may be generated between the tips of the flaps. It was.

  The problem to be solved by the present invention is to provide a corrugated cardboard box which is easy to pack products and has excellent flap matching accuracy.

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 normal ruled line is formed with the back liner side recessed so that the flap is folded inside the peripheral wall,
A groove-like reverse ruled line is formed on the side of the flap with respect to the normal ruled line, 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 corrugated cardboard box, wherein a weak ruled line is formed on the opposite side of the normal ruled line across the reverse ruled line, in parallel with the reverse ruled line, with the back liner side being recessed.

  In this way, since the weak ruled line is formed on the opposite side of the normal ruled line across the reverse ruled line, it is possible to prevent the flap from being folded between the normal ruled line and the reverse ruled line when the flap is folded outside the peripheral wall. The flap can be folded along the reverse ruled line with high accuracy. Therefore, when the flap is folded outside the box and the product is inserted into the box, the flap is prevented from being folded between the normal ruled line and the reverse ruled line when the flap is folded inside the box and the box is sealed. It is possible to prevent a gap from being generated between the tips of the two.

  It is preferable to form a weak reverse ruled line in which the front liner side is recessed in parallel to the normal ruled line on the opposite side of the reverse ruled line across the normal ruled line.

  In this way, since the weak reverse ruled line is formed on the opposite side of the reverse ruled line sandwiching the normal ruled line, the flap is prevented from being folded between the normal ruled line and the reverse ruled line when the flap is folded inside the peripheral wall. be able to. Therefore, when the flap is folded outside the box and the product is inserted into the box, the flap is folded between the normal ruled line and the reverse ruled line more effectively when the flap is folded inside the box and the box is sealed. Can be prevented.

The present invention also provides a ruled line forming method having the following configuration as a ruled line forming method for a corrugated cardboard sheet suitable for manufacturing the 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 on the back liner side, and the parallel ruled line A method of forming a ruled line on a corrugated cardboard sheet, comprising forming a groove-like reverse ruled line having a concave on the front liner side and a weak ruled line having a concave on the back liner side in parallel with the reverse ruled line on the opposite side of the normal ruled line sandwiching the reverse ruled line. And
A pair of normal crease rings that sandwich the cardboard sheet and a pair of reverse crease rings that sandwich the cardboard sheet at a position shifted upstream or downstream of the pair of normal crease rings,
On the outer periphery of the normal crease ring on the back liner side, there are provided convex portions that are continuous in the circumferential direction and concave portions that are located on both sides in the axial direction of the convex portion, and on the outer periphery of the normal crease ring on the front liner side A groove portion facing the convex portion, and a groove shoulder portion located on both axial sides of the groove portion,
On the outer periphery of the reverse crease ring on the front liner side, there are provided a convex portion continuous in the circumferential direction and concave portions located on both sides in the axial direction of the convex portion, and on the outer periphery of the reverse crease line ring on the back liner side A groove portion facing the convex portion, and a groove shoulder portion located on both axial sides of the groove portion,
In the pair of normal ruled ring and the pair of reverse ruled ring, the position of the convex portion of the normal ruled ring on the back liner side corresponds to the position of one groove shoulder of the reverse ruled ring on the back liner side. And, the position of the convex part of the reverse crease ring on the front liner side is arranged so as to correspond to the position of one groove shoulder part of the normal crease ring on the front liner side,
Forming the normal ruled line by sandwiching the corrugated sheet between the convex part of the normal ruled ring on the back liner side and the groove part of the normal ruled ring on the front liner side,
Forming the reverse ruled line by sandwiching the corrugated sheet between the groove part of the reverse ruled line ring on the back liner side and the convex part of the reverse ruled line ring on the front liner side,
A method for forming a ruled line on a corrugated cardboard sheet, wherein the weak ruled line is formed by sandwiching the corrugated sheet between a groove shoulder of the reverse ruled line ring on the back liner side and a concave part of the reverse ruled ring on the front liner side.

  In this way, when the corrugated sheet is sandwiched between a pair of normal crease rings, the reverse crease portion of the corrugated cardboard sheet is the groove shoulder of the normal crease ring on the front liner side and the recess of the normal crease ring on the back liner side. Compressed between. Therefore, it becomes possible to effectively crush the reverse ruled line portion of the cardboard sheet. Also, when the corrugated sheet is sandwiched between a pair of reverse crease rings, the normal crease part of the corrugated cardboard sheet is between the groove shoulder of the reverse crease ring on the back liner side and the recess of the reverse crease ring on the front liner side. It is compressed with. Therefore, it is possible to effectively crush the normal ruled line portion of the cardboard sheet.

  Furthermore, a weak reverse ruled line can be formed by sandwiching the corrugated cardboard sheet between the concave part of the normal ruled ring on the back liner side and the groove shoulder of the normal ruled ring on the front liner side. The weak reverse ruled line is a weak ruled line in which the front liner side is recessed parallel to the normal ruled line on the opposite side of the reverse ruled line across the normal ruled line.

  Further, in place of the pair of normal crease rings and the pair of reverse crease rings, a pair of special crease rings arranged on the back liner side and the front liner side of the corrugated cardboard sheet are used. By sandwiching the corrugated sheet with a ruled ring, the normal ruled line, the reverse ruled line, the weak ruled line, and the weak reverse ruled line can be formed simultaneously.

  In this way, it is possible to manage the relative positional relationship between the normal ruled line, the reverse ruled line, the weak ruled line, and the weak reverse ruled line with high accuracy, and the peeling between the core of the corrugated cardboard sheet and the front and back liners can be prevented. It becomes possible to prevent.

The present invention also provides a ruled line forming apparatus having the following configuration as a ruled line forming apparatus for corrugated cardboard sheets suitable for manufacturing the 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 on the back liner side, and the parallel ruled line A cardboard sheet ruled line forming device for forming a groove-like reverse ruled line having a concave on the front liner side and a weak ruled line having a concave on the back liner side parallel to the reverse ruled line on the opposite side of the normal ruled line sandwiching the reverse ruled line. And
A pair of normal crease rings that sandwich the cardboard sheet, and a pair of reverse crease rings that sandwich the cardboard sheet at a position shifted upstream or downstream of the pair of normal crease rings,
On the outer periphery of the normal crease ring on the back liner side, there are provided convex portions that are continuous in the circumferential direction and concave portions that are located on both sides in the axial direction of the convex portion, and on the outer periphery of the normal crease ring on the front liner side A groove portion facing the convex portion, and a groove shoulder portion located on both axial sides of the groove portion,
On the outer periphery of the reverse crease ring on the front liner side, there are provided a convex portion continuous in the circumferential direction and concave portions located on both sides in the axial direction of the convex portion, and on the outer periphery of the reverse crease line ring on the back liner side A groove portion facing the convex portion, and a groove shoulder portion located on both axial sides of the groove portion,
In the pair of normal ruled ring and the pair of reverse ruled ring, the position of the convex portion of the normal ruled ring on the back liner side corresponds to the position of one groove shoulder of the reverse ruled ring on the back liner side. And, the position of the convex part of the reverse crease ring on the front liner side is arranged so as to correspond to the position of one groove shoulder part of the normal crease ring on the front liner side,
The pair of normal ruled ring forms the normal ruled line by sandwiching the corrugated sheet between the convex part of the normal ruled ring on the back liner side and the groove part of the normal ruled ring on the front liner side,
The pair of reverse crease rings form the reverse crease by sandwiching the corrugated sheet between a groove portion of the reverse crease ring on the back liner side and a convex portion of the reverse crease ring on the front liner side, A cardboard sheet ruled line forming apparatus for forming the weak ruled line by sandwiching the cardboard sheet between a groove shoulder of the reverse ruled line ring on the back liner side and a concave part of the reverse ruled ring on the front liner side.

  In this way, when the corrugated sheet is sandwiched between a pair of normal crease rings, the reverse crease portion of the corrugated cardboard sheet is the groove shoulder of the normal crease ring on the front liner side and the recess of the normal crease ring on the back liner side. Compressed between. For this reason, the reverse ruled line portion of the cardboard sheet can be effectively crushed, and a reverse ruled line having stable folding accuracy can be obtained. Also, when the corrugated sheet is sandwiched between a pair of reverse crease rings, the normal crease part of the corrugated cardboard sheet is between the groove shoulder of the reverse crease ring on the back liner side and the recess of the reverse crease ring on the front liner side. It is compressed with. As a result, the normal ruled line portion of the cardboard sheet can be effectively crushed, and a normal ruled line having stable folding accuracy can be obtained.

  Further, the pair of normal crease rings form a weakly reverse crease by sandwiching the corrugated sheet between a recess of the normal crease ring on the back liner side and a groove shoulder of the normal crease ring on the front liner side. Can be configured to. The weak reverse ruled line is a weak ruled line in which the front liner side is recessed parallel to the normal ruled line on the opposite side of the reverse ruled line across the normal ruled line.

  The ruled line forming device can be incorporated in the middle of a corrugating machine for producing a corrugated cardboard sheet, for example. In this case, the pair of normal ruled line rings and the pair of reverse ruled line rings are provided as a part of a scorer that forms the normal ruled lines on a corrugated cardboard sheet that is continuous in a strip shape in the middle of the corrugating machine.

  Further, the ruled line forming apparatus can be incorporated into a cutting machine that cuts a sheet of corrugated cardboard produced by a corrugating machine, for example. In this case, the pair of normal ruled line rings and the pair of reverse ruled line rings are provided as a part of a cutting machine for cutting a sheet of cardboard sheets into a predetermined width.

  Further, the ruled line forming apparatus has a pair of special ruled line rings arranged on the back liner side and the front liner side of the cardboard sheet in place of the pair of normal ruled line rings and the pair of reverse ruled line rings. And the normal crease line, the reverse crease line, the weak crease line, and the weak reverse crease line can be formed at the same time.

  In this way, it is possible to manage the relative positional relationship between the normal ruled line, the reverse ruled line, the weak ruled line, and the weak reverse ruled line with high accuracy, and the peeling between the core of the corrugated cardboard sheet and the front and back liners can be prevented. It becomes possible to prevent.

  The corrugated cardboard box according to the present invention has a groove-like reverse ruled line that is recessed on the front liner side so that the flap is folded to the outside of the peripheral wall. In addition, since the weak ruled line is formed on the opposite side of the normal ruled line across the reverse ruled line, it is possible to prevent the flap from being folded between the normal ruled line and the reverse ruled line when folding the flap to the outside of the peripheral wall. The flap can be folded along the reverse ruled line with high accuracy. Therefore, when the flap is folded outside the box and the product is inserted into the box, the flap is prevented from being folded between the normal ruled line and the reverse ruled line when the flap is folded inside the box and the box is sealed. Excellent in matching accuracy.

The figure which looked at the blank of the cardboard box of this embodiment from the back liner side Enlarged view of the vicinity of the normal ruled line and the reverse ruled line between the upper flap and the side plate of the blank shown in FIG. Enlarged cross-sectional view along line III-III in FIG. 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. 4 to the outer side of the surrounding wall, and inserted the goods in the cardboard box The perspective view which shows the process in which the upper flap shown in FIG. 5 is folded 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. 6, and sealed the cardboard box Sectional view along line VIII-VIII in FIG. Sectional view along line IX-IX in FIG. Sectional drawing which shows the part of the slitter scorer of the corrugating machine suitable for manufacture of the corrugated cardboard sheet | seat which forms the blank shown in FIG. Partially enlarged sectional view showing the relative positional relationship in the axial direction of the reverse crease ring and the normal crease ring of FIG. Sectional drawing which shows the other example of the slitter scorer of FIG. 10 is a partially enlarged cross-sectional view showing the relative positional relationship in the axial direction between the reverse crease ring and the normal crease ring when the positional relationship between the reverse crease ring and the normal crease ring shown in FIG. 10 is exchanged between the upstream side and the downstream side. Partially enlarged cross-sectional view of the normal crease ring used in the test FIG. 11 is a partially enlarged cross-sectional view of a special ruled ring schematically showing an example using a special ruled ring in which the reverse ruled ring and the normal ruled ring shown in FIG. 11 are integrated. Sectional drawing which shows the example which provided the ruled line formation apparatus as a part of cutting machine which cuts the cardboard sheet | seat of a sheet into a predetermined width dimension 3 is an enlarged cross-sectional view showing a comparative example in which only the normal ruled line and the reverse ruled line are formed without the weak ruled line and the weak reverse ruled line in FIG.

  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 8 located at the end via a ruled line 9. The side plates 5, 6, 7, and 8 are parts that constitute the peripheral wall 31 (see FIG. 4) when the cardboard box 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.

  A reverse ruled line 16 for folding the upper flaps 11, 12, 13, 14 outward is formed at the end of each upper flap 11, 12, 13, 14 on the base side (that is, the side close to the normal ruled line 15). Yes. The reverse ruled lines 16 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 16 extends in a direction perpendicular to the corrugated cardboard. Between the adjacent upper flaps 11, 12, 13, and 14, a cut groove 17 parallel to the step is provided, and the upper flaps 11, 12, 13, and 14 are separated from each other through the cut groove 17. It has become.

  Lower flaps 18, 19, 20, and 21 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 18, 19, 20, 21, ruled lines 22 are formed for folding the lower flaps 18, 19, 20, 21 inward. The ruled line 22 extends in a direction perpendicular to the corrugated cardboard. Between the adjacent lower flaps 18, 19, 20, 21, a cut groove 23 parallel to the step is provided, and the lower flaps 18, 19, 20, 21 are separated from each other via the cut groove 23. It has become.

  As shown in FIGS. 2 and 3, the normal ruled line 15 is formed in a groove shape in which the back liner 2 side is recessed, and the upper flaps 11, 12, 13, and 14 are arranged on the back liner 2 side along the normal ruled line 15. It can be folded. On the other hand, the reverse ruled line 16 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 can be folded along the reverse ruled line 16 to the side of the front liner 1. Yes.

  As shown in FIG. 3, a weak ruled line 24 is formed in parallel to the reverse ruled line 16 on the opposite side of the normal ruled line 15 across the reverse ruled line 16. The weak ruled line 24 is a weakly crushed line in which the back liner 2 side is recessed shallower than the normal ruled line 15. A weak reverse ruled line 25 is formed in parallel to the normal ruled line 15 on the opposite side of the reverse ruled line 16 with the normal ruled line 15 interposed therebetween. The weak reverse ruled line 25 is a weakly crushed line in which the front liner 1 side is recessed shallower than the reverse ruled line 16.

  The reverse ruled lines 16 are arranged so that the distance between the center of the normal ruled lines 15 and the center of the reverse ruled lines 16 is 3 mm or more and 7 mm or less. The weak ruled lines 24 are arranged so that the distance between the center of the reverse ruled line 16 and the center of the weak ruled line 24 is 2 mm or more and 6 mm or less. The weak reverse ruled lines 25 are arranged so that the distance between the center of the normal ruled lines 15 and the center of the weak reverse ruled lines 25 is 2 mm or more and 6 mm or less. Here, the center of the normal ruled line 15 and the center of the weak ruled line 24 are respectively the most recessed positions from the surface of the back liner 2, and the center of the reverse ruled line 16 and the center of the weak reverse ruled line 25 are respectively the front liner 1. It is the most recessed position from the surface.

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

  As shown in FIG. 4, the side plates 5, 6, 7, 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 8 at one end is connected to the other end. Are adhered to the inner surface of the side plate 5, and the peripheral wall 31 is formed by these side plates 5, 6, 7, 8. Next, the lower flaps 18, 20 connected to the lower ends of the side plates 5, 7 corresponding to the width surface of the cardboard box 30 are bent along the ruled line 22 to the inside of the peripheral wall 31, and then the length surface of the cardboard box 30. The lower flaps 19, 21 connected to the lower ends of the side plates 6, 8 are bent along the ruled line 22 inside the peripheral wall 31, and the lower flaps 18, 19, 20, 21 open the lower end opening of the peripheral wall 31. A closed bottom 32 is formed. In the drawing, the interval between the normal ruled line 15 and the reverse ruled line 16 is exaggerated and larger than the actual one.

  Next, the product is boxed. At this time, as shown in FIG. 4, the product 33 (see FIG. 5) can be inserted into the cardboard box 30 with the upper flaps 11, 12, 13, 14 extending straight above the peripheral wall 31. However, particularly when the product 33 is inserted manually, in the state shown in FIG. 4, it is difficult to insert the product 33 because the upper flaps 11, 12, 13, 14 are obstructive.

  Therefore, in order to facilitate insertion of the product 33 into the cardboard box 30, the upper flaps 11, 12, 13, and 14 are folded to the outside of the peripheral wall 31 (so-called reverse folding) as shown in FIG. Here, since the regular ruled line 15 is formed in a groove shape in which the side of the back liner 2 is recessed, when the upper flaps 11, 12, 13, 14 are folded to the side of the back liner 2, the upper flaps 11, 12, 13 , 14 folds smoothly along the normal ruled line 15, but it requires a relatively large force to fold the upper flaps 11, 12, 13, 14 along the normal ruled line 15 toward the front liner 1. . On the other hand, since the reverse ruled line 16 has a groove shape with the front liner 1 side recessed, when the upper flaps 11, 12, 13, 14 are folded toward the front liner 1, the upper flaps 11, 12, 13, 14 folds smoothly along the reverse ruled line 16, but has a characteristic that a relatively large force is required to fold the upper flaps 11, 12, 13, 14 along the reverse ruled line 16 toward the back liner 2. Therefore, when the upper flaps 11, 12, 13, 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, 14 are not folded at the regular ruled line 15, but are folded along the reverse ruled line 16 ( (See FIG. 8).

  FIG. 5 shows an example in which the upper flaps 11, 12, 13, and 14 are all folded, but 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. 6 and 7, the upper flaps 11 and 13 are bent along the normal ruled line 15 to the inside of the peripheral wall 31, and the upper flaps 12 and 14 are bent along the normal ruled line 15 to the inside of the peripheral wall 31. Here, when the upper flaps 11, 12, 13, 14 are folded inside the peripheral wall 31 (forward fold), the upper flaps 11, 12, 13, 14 are in accordance with the characteristics of the normal ruled line 15 and the reverse ruled line 16 described above. Instead of being folded along the reverse ruled line 16, it is folded along the normal ruled line 15 (see FIG. 9). Thereafter, the upper flaps 12 and 14 are fixed by a fixing means (not shown) such as an adhesive tape, a stapler, or a hot melt, thereby completing the sealing of the box.

  By the way, when the normal ruled line 15 having the concave side of the back liner 2 and the reverse ruled line 16 having the concave side of the front liner 1 are formed close to each other, the thickness of the corrugated cardboard between the normal ruled line 15 and the reverse ruled line 16 is thin. Become. Therefore, for example, as shown in FIG. 17, when only the normal ruled line 15 and the reverse ruled line 16 are formed without the weak ruled line 24 and the weak reverse ruled line 25, the upper flap 11 is folded to the front liner 1 side. The cardboard may not be folded at the center of the reverse ruled line 16 and may be folded at a position between the normal ruled line 15 and the reverse ruled line 16 (for example, a position indicated by a line K in FIG. 17). Once the upper flap 11 is folded between the normal ruled line 15 and the reverse ruled line 16, the strength of the portion between the normal ruled line 15 and the reverse ruled line 16 is lowered. Thereafter, the upper flap 11 is folded to the back liner 2 side. At this time, the upper flap 11 does not break accurately at the center of the normal ruled line 15, but again breaks between the normal ruled line 15 and the reverse ruled line 16.

  On the other hand, as shown in FIG. 3, the cardboard box 30 of this embodiment has weak ruled lines 24 formed on the opposite side of the normal ruled lines 15 with the reverse ruled lines 16 interposed therebetween. The area becomes thinner. Therefore, as shown in FIG. 5, when the upper flaps 11, 12, 13, 14 are folded outside the peripheral wall 31, the upper flaps 11, 12, 13, 14 are folded between the normal ruled line 15 and the reverse ruled line 16. Therefore, the upper flaps 11, 12, 13, and 14 can be folded along the reverse ruled line 16 with high accuracy. Further, since the weak reverse ruled line 25 is formed on the opposite side of the reverse ruled line 16 across the normal ruled line 15, the areas on both sides including the normal ruled line 15 are thinned. Therefore, when the upper flaps 11, 12, 13, 14 are folded inside the peripheral wall 31, the upper flaps 11, 12, 13, 14 can be prevented from being folded between the normal ruled line 15 and the reverse ruled line 16, The upper flaps 11, 12, 13, and 14 can be folded along the ruled line 15 with high accuracy.

  As described above, the cardboard box 30 is formed with the groove-like reverse ruled line 16 in which the front liner 1 side is recessed so that the upper flaps 11, 12, 13, and 14 are folded outside the peripheral wall 31. 33 is easy to pack. Further, since the weak ruled line 24 is formed on the opposite side of the normal ruled line 15 across the reverse ruled line 16, when the upper flaps 11, 12, 13, 14 are folded outside the peripheral wall 31, the normal ruled line 15 and the reverse ruled line 16 are formed. The upper flaps 11, 12, 13, 14 can be prevented from breaking between the upper flaps 11, 12, 13, 14, and the upper flaps 11, 12, 13, 14 can be folded along the reverse ruled line 16 with high accuracy. Therefore, when the upper flaps 11, 12, 13, and 14 are folded outside the box and the product 33 is inserted into the box, the upper flaps 11, 12, 13, and 14 are folded inside the box and the box is sealed. The upper flaps 11, 12, 13, and 14 can be prevented from being folded between the normal ruled line 15 and the reverse ruled line 16, and a gap can be prevented from being formed between the tips of the upper flaps 12 and 14, and the upper flap can be prevented. Excellent butt accuracy of 12,14.

  Moreover, since this cardboard box 30 is formed with a weak reverse ruled line 25 on the opposite side of the reverse ruled line 16 sandwiching the regular ruled line 15, when the upper flaps 11, 12, 13, 14 are folded inside the peripheral wall 31, It is possible to prevent the upper flaps 11, 12, 13, and 14 from breaking between the normal ruled line 15 and the reverse ruled line 16. Therefore, when the upper flaps 11, 12, 13, and 14 are folded outside the box and the product 33 is inserted into the box, the upper flaps 11, 12, 13, and 14 are folded inside the box and the box is sealed. More effectively, the upper flaps 11, 12, 13, and 14 can be prevented from being folded between the normal ruled line 15 and the reverse ruled line 16.

  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 has a single facer (not shown), a double facer (not shown), a slitter scorer 40 (see FIG. 10), and a cutoff (not shown) in order from the upstream side toward the downstream side. 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. 10, the slitter scorer 40 includes a scorer 41 and a slitter 42. The scorer 41 includes rotating shafts 51 and 52 arranged above and below the corrugated cardboard sheet 43, a normal ruled line ring 53 fixed to the upper rotating shaft 51, and a normal ruled line ring 54 fixed to the lower rotating shaft 52. The corrugated cardboard sheet 43 is sandwiched between upper and lower normal ruled line rings 53 and 54.

  As shown in FIG. 11, the outer periphery of the upper normal ruled ring 53 is provided with a convex portion 55 that is continuous in the circumferential direction over the entire circumference, and concave portions 56 that are positioned on both sides in the axial direction of the convex portion 55. . On the outer periphery of the lower normal ruled ring 54, a groove portion 57 facing the convex portion 55 and groove shoulder portions 58 positioned on both sides in the axial direction of the groove portion 57 are provided. In the scorer 41, the corrugated sheet 43 is sandwiched between the convex portion 55 of the upper normal ruled ring 53 and the groove portion 57 of the lower normal ruled ring 54, so that the upper side (that is, the back liner 2 side) is recessed. Ruled lines 15 (see FIG. 3) are formed on the cardboard sheet 43.

  Further, as shown in FIG. 10, the scorer 41 has a reverse ruled line forming unit 44. The reverse ruled line forming unit 44 includes rotating shafts 61 and 62 arranged above and below the corrugated cardboard sheet 43, a reverse ruled line ring 63 fixed to the upper rotating shaft 61, and a reverse ruled line fixed to the lower rotating shaft 62. And the reverse crease lines 63 and 64 sandwich the corrugated cardboard sheet 43 at positions shifted upstream of the normal crease rings 53 and 54.

  As shown in FIG. 11, on the outer periphery of the lower reverse ruled ring 64, there are provided a convex portion 65 that is continuous in the circumferential direction over the entire circumference, and a concave portion 66 that is located on both sides in the axial direction of the convex portion 65. Yes. On the outer periphery of the upper reverse ruled line ring 63, a groove portion 67 facing the convex portion 65 and groove shoulder portions 68 positioned on both sides in the axial direction of the groove portion 67 are provided. The reverse ruled line forming portion 44 sandwiches the corrugated cardboard sheet 43 between the groove portion 67 of the upper reverse ruled line ring 63 and the convex portion 65 of the lower reverse ruled line ring 64, thereby lower side (that is, the front liner 1 side). A reverse ruled line 16 (see FIG. 3) having a concave is formed on the cardboard sheet 43.

  Here, the upper and lower normal ruled ring rings 53 and 54 and the upper and lower reverse ruled line rings 63 and 64 are such that the position of the convex portion 55 of the upper normal ruled line ring 53 is the position of one groove shoulder 68 of the upper reverse ruled line ring 63. And the position of the convex portion 65 of the lower reverse ruled line ring 64 is arranged so as to correspond to the position of one groove shoulder 58 of the lower normal ruled line ring 54. That is, when the corrugated cardboard sheet 43 sequentially passes through the reverse ruled line rings 63 and 64 and the normal ruled line rings 53 and 54, a portion passing through one groove shoulder 68 of the reverse ruled line ring 63 is a convex portion of the normal ruled line ring 53. A portion passing through 55 and passing through the convex portion 65 of the reverse crease ring 64 passes through one groove shoulder 58 of the normal crease ring 54.

  The upper and lower reverse crease rings 63 and 64 are formed by sandwiching the corrugated cardboard sheet 43 between the groove shoulder 68 of the upper reverse crease ring 63 and the concave portion 66 of the lower reverse crease ring 64 so that the weak ruled line 24 (see FIG. 3). ) Is set to the size of the gap between the groove shoulder 68 and the recess 66. Further, the upper and lower normal ruled rings 53 and 54 are formed so that the corrugated cardboard sheet 43 is sandwiched between the concave portions 56 of the upper normal ruled ring 53 and the groove shoulders 58 of the lower normal ruled ring 54, whereby the weak reverse ruled line 25 ( The size of the gap between the recess 56 and the groove shoulder 58 is set so as to form (see FIG. 3).

The normal ruled line rings 53 and 54 and the reverse ruled line rings 63 and 64 have an axial displacement amount x between the center of the convex part 55 of the normal ruled line ring 53 and the convex part 65 of the reverse ruled line ring 64, and the groove part of the normal ruled line ring 54. When the width of 57 is a, the width of the groove shoulder 58 is b, and the width of the convex portion 65 of the reverse ruled line ring 64 is c, they are arranged so as to satisfy the following expression.
1 / 2a-1 / 2c ≦ x ≦ 1 / 2a + b + 1 / 2c

  As shown in FIG. 10, the reverse ruled line forming unit 44 includes an elevating drive device 45 for the upper reverse ruled line ring 63. When the reverse ruled line 16 is not formed on the cardboard sheet 43, the lifting drive unit 45 raises the upper reverse ruled line ring 63, and when the reverse ruled line 16 is formed on the cardboard sheet 43, the lift drive unit 45 is moved upward. The ring 63 is lowered.

  The slitter 42 includes rotating shafts 71 and 72 disposed above and below the cardboard sheet 43, a knife receiver 73 fixed to the upper rotating shaft 71, and a slitter knife 74 fixed to the lower rotating shaft 72. . On the outer periphery of the slitter knife 74, a continuous cutting edge is formed over the entire circumference in the circumferential direction. The slitter knife 74 is a rotary blade that cuts into the corrugated cardboard sheet 43 from the lower side (that is, the front liner 1 side) and cuts the corrugated cardboard sheet 43 along the conveying direction (that is, the direction perpendicular to the step).

  The slitter scorer 40 includes a frame 80 that supports the upper rotary shafts 51, 71 and the lower rotary shafts 52, 72, a base member 81 fixed to the floor surface F, and between the frame 80 and the base member 81. And a linear guide 82 provided. The linear guide 82 supports the frame 80 so as to be movable in a horizontal direction perpendicular to the conveying direction of the cardboard sheet 43. Further, when the position of the corrugated cardboard sheet 43 passing through the slitter scorer 40 changes in a direction perpendicular to the conveying direction, a frame moving device 83 that moves the frame 80 following the change in the position of the corrugated cardboard sheet 43 is provided. Is attached.

  The reverse ruled line forming portion 44 includes an auxiliary frame 84 that supports the upper and lower rotary shafts 61 and 62, a base member 85 fixed to the floor surface F, and a linear guide 86 provided between the auxiliary frame 84 and the base member 85. And have. The linear guide 86 supports the auxiliary frame 84 so as to be movable in a horizontal direction perpendicular to the conveying direction of the cardboard sheet 43. The auxiliary frame 84 is provided with a connection bracket 87 that is connected to the frame 80 of the slitter scorer 40. By connecting the frame 80 and the auxiliary frame 84 to each other via the connection bracket 87, when the frame moving device 83 moves the frame 80 of the slitter scorer 40, the auxiliary frame 84 also moves together with the frame 80. It is like that.

  When the corrugated machine is used to manufacture the corrugated cardboard sheet 43, when the corrugated cardboard sheet 43 is sandwiched between the upper and lower reverse ruled line rings 63 and 64, the groove portion 67 of the upper reverse ruled line ring 63 and the lower reverse ruled line ring 64 When the corrugated cardboard sheet 43 is sandwiched between the convex portions 65, the reverse ruled line 16 is formed, and at the same time, between the groove shoulder 68 of the upper reverse ruled line ring 63 and the concave portion 66 of the lower reverse ruled line ring 64. The weak ruled line 24 is formed by the cardboard sheet 43 being sandwiched between the two. Thereafter, when the corrugated cardboard sheet 43 is sandwiched between the upper and lower normal ruled line rings 53 and 54, the corrugated cardboard sheet is disposed between the convex part 55 of the upper normal ruled line ring 53 and the groove part 57 of the lower normal ruled line ring 54. As a result, the cardboard sheet 43 is sandwiched between the concave portion 56 of the upper normal ruled ring 53 and the groove shoulder 58 of the lower normal ruled ring 54. A weak reverse ruled line 25 is formed. In this way, the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24, and the weak reverse ruled line 25 are formed on the cardboard sheet 43.

  When the corrugated sheet 43 is manufactured by the corrugating machine described above, when the corrugated sheet 43 is sandwiched between the upper and lower normal crease rings 53 and 54, the reverse crease 16 portion of the corrugated cardboard sheet 43 becomes the groove of the lower normal crease ring 54. Compression is performed between the shoulder portion 58 and the concave portion 56 of the upper normal ruled ring 53. Therefore, it is possible to effectively crush the portion of the reverse ruled line 16 of the corrugated cardboard sheet 43, and the reverse ruled line 16 having a stable folding accuracy can be obtained. When the corrugated sheet 43 is sandwiched between the upper and lower reverse crease rings 63 and 64, the portion of the normal crease 15 of the corrugated cardboard sheet 43 is the groove shoulder 68 of the upper reverse crease ring 63 and the lower reverse crease ring 64. , And is compressed between the recesses 66. Therefore, the portion of the normal ruled line 15 of the cardboard sheet 43 can be effectively crushed, and the normal ruled line 15 having stable folding accuracy can be obtained.

  When the auxiliary frame 84 of the reverse ruled line forming unit 44 is formed separately from the frame 80 of the slitter scorer 40 as in the above embodiment, the reverse ruled line forming unit 44 is introduced by remodeling the existing slitter scorer 40. However, when a new slitter scorer 40 is introduced into a corrugating machine, for example, as shown in FIG. 12, the reverse ruled line forming portion 44 is incorporated into the frame 80 of the slitter scorer 40 as an integrated device. It is also possible.

  In the above embodiment, the reverse ruled line rings 63 and 64 are described as examples provided at positions shifted upstream of the normal ruled line rings 53 and 54. However, as shown in FIG. The rings 63 and 64 may be provided at positions shifted to the downstream side of the normal ruled rings 53 and 54. As such an embodiment, for example, the reverse ruled line forming unit 44 shown in FIG. 10 is moved to the downstream side of the slitter scorer 40, or the normal ruled line rings 53 and 54 and the reverse ruled line ring 63 shown in FIG. , 64 are replaced with each other.

  In the above embodiment, the normal ruled line 15 and the weak reverse ruled line are provided by the upper and lower normal ruled line rings 53 and 54 provided separately from the upper and lower reverse ruled line rings 63 and 64 for forming the reverse ruled line 16 and the weak ruled line 24 on the cardboard sheet 43. 15, as shown in FIG. 15, by using the upper special ruled ring 88 and the lower special ruled ring 89 and sandwiching the corrugated cardboard sheet 43 between the upper and lower special ruled rings 88 and 89, It is also possible to simultaneously form the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24, and the weak reverse ruled line 25 shown in FIG.

  As shown in FIG. 15, on the outer periphery of the upper special crease ring 88, there are recesses 56 and protrusions 55 on the outer periphery of the upper normal crease ring 53 and grooves 67 and shoulders 68 on the outer periphery of the upper reverse crease ring 63. The concave portion 56, the convex portion 55, the groove portion 67, and the groove shoulder portion 68 are provided in order in the axial direction. The outer periphery of the lower special crease ring 89 corresponds to the outer peripheral groove shoulder 58 and groove 57 of the lower normal crease ring 54 and the outer convex portion 65 and concave portion 66 of the lower reverse crease ring 64. The groove shoulder portion 58, the groove portion 57, the convex portion 65, and the concave portion 66 are sequentially provided side by side in the axial direction.

  The recess 56 of the upper special ruled ring 88 and the groove shoulder 58 of the lower special ruled ring 89 form the weak reverse ruled line 25 (see FIG. 3) by sandwiching the corrugated cardboard sheet 43, and the upper special ruled ring 88 The convex portion 55 and the groove portion 57 of the lower special ruled line ring 89 form the normal ruled line 15 (see FIG. 3) by sandwiching the corrugated cardboard sheet 43, and the groove portion 67 of the upper special ruled line ring 88 and the lower special ruled line ring 88. The convex part 65 of the ruled line ring 89 forms the reverse ruled line 16 (see FIG. 3) by sandwiching the corrugated cardboard sheet 43, and the groove shoulder part 68 of the upper special ruled line ring 88 and the concave part 66 of the lower special ruled line ring 89. Forms the weak ruled line 24 (see FIG. 3) by sandwiching the corrugated cardboard sheet 43 therebetween.

The height h ₁ from the minimum diameter portion of the groove portion 67 of the upper special crease ring 88 to the maximum diameter portion of the groove shoulder portion 68 is from the minimum diameter portion of the groove portion 67 of the upper special crease ring 88 to the maximum diameter of the convex portion 55. It is set smaller than the height h ₂ to the moiety. The height h ₃ from the minimum diameter portion of the groove portion 57 of the lower special crease ring 89 to the maximum diameter portion of the groove shoulder portion 58 is from the minimum diameter portion of the groove portion 57 of the lower special crease ring 89 to the convex portion 65. It is set smaller than the height h ₄ up to the maximum diameter portion.

The height h ₁ from the smallest diameter portion of the groove portion 67 of the upper special crease ring 88 to the largest diameter portion of the groove shoulder portion 68 is from the smallest diameter portion of the groove portion 57 of the lower special crease ring 89 to the groove shoulder portion. It is set to the same height as the height h ₃ of up to a maximum diameter portion of the 58. The height h ₂ from the minimum diameter portion of the groove portion 67 of the upper special crease ring 88 to the maximum diameter portion of the convex portion 55 is from the minimum diameter portion of the groove portion 57 of the lower special crease ring 89 to the maximum diameter of the convex portion 65. It is set to the height h ₄ of the same height to the part.

  When the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24 and the weak reverse ruled line 25 are simultaneously formed using the upper and lower special ruled line rings 88 and 89, the relative positional relationship between the ruled lines 15, 16, 24 and 25. Can be managed with high accuracy, and peeling between the core 3 of the corrugated cardboard sheet 43 and the front and back liners 1 and 2 can be prevented.

  That is, as shown in FIG. 11, the reverse ruled line 16 and the weak ruled line 24 are formed on the corrugated cardboard sheet 43 by the upper and lower reverse ruled line rings 63, 64, and the upper and lower normal ruled line rings 53, 53 arranged upstream or downstream thereof. 54, when the normal ruled line 15 and the weak reverse ruled line 25 are formed, when the corrugated cardboard sheet 43 meanders, the positions of the normal ruled line 15 and the weak reverse ruled line 25 shown in FIG. There is a risk of relative displacement. On the other hand, as shown in FIG. 15, when the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24, and the weak reverse ruled line 25 are simultaneously formed using the upper and lower special ruled line rings 88 and 89, the corrugated cardboard sheet 43 meanders. Sometimes, the positions of the normal ruled lines 15 and the weak reverse ruled lines 25 shown in FIG. 3 are not likely to be shifted with respect to the positions of the reverse ruled lines 16 and the weak ruled lines 24, and the relative ruled lines 15, 16, 24, 25 are relative to each other. It becomes possible to manage a specific positional relationship with high accuracy.

  Further, as shown in FIG. 11, the reverse ruled line 16 and the weak ruled line 24 are formed on the corrugated cardboard sheet 43 by the upper and lower reverse ruled line rings 63, 64, and the upper and lower reverse ruled line rings 63, 64 on the upstream side or the downstream side thereof. When the normal ruled line 15 and the weak reverse ruled line 25 are formed by the upper and lower normal ruled line rings 53 and 54 provided separately, the corrugated cardboard sheet 43 is aligned with the upper and lower reverse ruled line rings 63 and 64 and the upper and lower normal ruled line rings 53 and 54. Therefore, the core 3 of the corrugated cardboard sheet 43 and the front liner 1 or the back of the corrugated board sheet 43 are caused by a shearing force acting between the core 3 of the corrugated cardboard sheet 43 and the front liner 1 or the back liner 2 at this time. There is a risk of peeling between the liner 2 and the liner 2. On the other hand, as shown in FIG. 15, when the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24, and the weak reverse ruled line 25 are simultaneously formed using the upper and lower special ruled line rings 88 and 89, the corrugated cardboard sheet 43 is Since it is sandwiched only once by the special ruled line rings 88 and 89, it is possible to prevent peeling between the core 3 of the corrugated cardboard sheet 43 and the front and back liners 1 and 2.

  In the above embodiment, the ruled line forming device provided as a part of the scorer 41 for forming the normal ruled line 15 on the corrugated machine 43 in the middle of the corrugating machine has been described as an example, but as shown in FIG. It is also possible to employ a ruled line forming apparatus provided as a part of a cutting machine that cuts a sheet of corrugated cardboard sheet 43 manufactured by a corrugating machine into a predetermined width dimension.

  FIG. 16 shows a ruled line forming apparatus for sheet corrugated cardboard sheets. This ruled line forming apparatus is a modification of a cutting machine that cuts a sheet of corrugated cardboard sheets 43 into a predetermined width. Hereinafter, parts corresponding to the ruled line forming apparatus shown in FIG.

  On the upstream side of the reverse ruled lines 63 and 64, a paper feed table 91 that supports the corrugated cardboard sheet 43 is provided. A paper discharge table 92 is provided on the downstream side of the slitter knife 74 and the knife receiver 73.

  A usage example of the ruled line forming apparatus will be described. When the sheet corrugated sheet 43 supported by the sheet feeding table 91 is fed, when the corrugated sheet 43 is sandwiched between the upper and lower reverse ruled ring rings 63 and 64, The reverse ruled line 16 is formed by sandwiching the corrugated cardboard sheet 43 between the convex part 65 of the reverse reverse ruled ring 64 on the side, and at the same time the groove shoulder 68 of the upper reverse ruled line ring 63 and the lower reverse ruled line ring 63 The weak ruled line 24 is formed by sandwiching the corrugated cardboard sheet 43 between the 64 concave portions 66. Thereafter, when the corrugated cardboard sheet 43 is sandwiched between the upper and lower normal ruled line rings 53 and 54, the corrugated cardboard sheet is disposed between the convex part 55 of the upper normal ruled line ring 53 and the groove part 57 of the lower normal ruled line ring 54. As a result, the cardboard sheet 43 is sandwiched between the concave portion 56 of the upper normal ruled ring 53 and the groove shoulder 58 of the lower normal ruled ring 54. A weak reverse ruled line 25 is formed. In this way, the normal ruled line 15, the reverse ruled line 16, the weak ruled line 24, and the weak reverse ruled line 25 are formed on the cardboard sheet 43. Thereafter, the corrugated cardboard sheet 43 is cut into a predetermined width by the slitter knife 74 and is discharged to the paper discharge table 92.

  In the above embodiment, the upper and lower normal ruled line rings 53 and 54 form the normal ruled line 15 and the weak reverse ruled line 25, and the upper and lower reverse ruled line rings 63 and 64 form the reverse ruled line 16 and the weak ruled line 24. After forming the normal ruled lines 15 and the weak reverse ruled lines 25 with the normal ruled line rings 53 and 54, it is also possible to form the reverse ruled lines 16 and the weak ruled lines 24 using a plate-shaped wooden mold with a platen die cutter (not shown).

  A test was performed in which the corrugated sheet 43 was manufactured by changing the axial relative position between the normal ruled rings 53 and 54 and the reverse ruled rings 63 and 64, and the corrugated sheet 43 was bent. The regular ruled rings 53 and 54 used in this test have the cross-sectional shape shown in FIG. 14 and the dimensions are as follows. Further, the reverse ruled lines 63 and 64 used in this test are members in which members having the same shape and the same dimensions as the normal ruled rings 53 and 54 are mounted upside down.

In Table 1, x _min and x _max are values defined by the following equations, respectively.
x _min = 1 / 2a-1 / 2c
x _max = 1 / 2a + b + 1 / 2c

  In Table 2, the normal ruled line GAP is the size of the gap between the convex part 55 of the normal ruled line ring 53 and the groove part 57 of the normal ruled line ring 54. The reverse ruled line GAP is the size of the gap between the convex part 65 of the reverse ruled line ring 64 and the groove part 67 of the reverse ruled line ring 63. x is the amount of axial displacement between the centers of the protrusions 55 of the normal ruled line ring 53 and the protrusions 65 of the reverse ruled line ring 64. “◯” indicates that the folding accuracy of the normal ruled line 15 and the reverse ruled line 16 was good. “X” indicates that the folding accuracy of the normal ruled line 15 or the reverse ruled line 16 is poor.

From the above test results, when the normal ruled line rings 53 and 54 and the reverse ruled line rings 63 and 64 are arranged so as to satisfy the following expression, the normal ruled line 15 and the reverse ruled line 16 having stable folding accuracy can be obtained. I understand.
1 / 2a-1 / 2c ≦ x ≦ 1 / 2a + b + 1 / 2c

  In the above embodiment, the upper flaps 11, 12, 13, and 14 have all been described with reference to the example of a corrugated cardboard box having the same shape (so-called A-type cardboard box). Cardboard box (for example, a so-called B which has an upper flap large enough to close the upper end opening of the peripheral wall and inserts an insertion piece connected to the tip of the upper flap into the peripheral wall 31 to form a lid. It can also be applied to a corrugated cardboard box.

  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 Reverse ruled line 24 Weak ruled line 25 Weak reverse ruled line 30 Cardboard box 31 Perimeter wall 41 Scorer 43 Cardboard sheet 53, 54 Normal ruled line ring 55 Convex part 56 concave portion 57 groove portion 58 groove shoulder portion 63, 64 reverse ruled line ring 65 convex portion 66 concave portion 67 groove portion 68 groove shoulder portion 88, 89 special ruled line ring

Claims (10)

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,
On the side of the flap (11, 12, 13, 14) with respect to the normal ruled line (15), the flap (11, 12, 13, 14) is parallel to the normal ruled line (15) and the peripheral wall (31 ), A groove-like reverse ruled line (16) having a concave on the front liner (1) side is formed so as to be folded outward,
On the opposite side of the normal ruled line (15) across the reverse ruled line (16), there is formed a weak ruled line (24) recessed in the back liner (2) side in parallel with the reverse ruled line (16). Characteristic cardboard box.   On the opposite side of the reverse ruled line (16) sandwiching the normal ruled line (15), a weak reverse ruled line (25) having a recess on the front liner (1) side is formed in parallel with the normal ruled line (15). Item 10. A cardboard box according to Item 1. A cardboard sheet (43) 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) recessed on the liner (2) side, a groove-like reverse ruled line (16) recessed on the front liner (1) side in parallel to the normal ruled line (15), and the reverse ruled line (16 A ruled line forming method for a corrugated cardboard sheet, forming a weak ruled line (24) recessed in the back liner (2) side in parallel with the reverse ruled line (16) on the opposite side of the normal ruled line (15) sandwiching
A pair of normal ruled line rings (53, 54) that sandwich the cardboard sheet, and a pair of normal ruled line rings (53, 54) that sandwich the cardboard sheet (43) at a position shifted upstream or downstream of the pair of normal ruled line rings (53, 54). Use a pair of reverse crease rings (63, 64)
On the outer periphery of the regular ruled ring (53) on the back liner (2) side, there are a convex portion (55) continuous in the circumferential direction and concave portions (56) located on both sides in the axial direction of the convex portion (55). Provided on the outer periphery of the normal ruled ring (54) on the side of the front liner (1) is a groove portion (57) facing the convex portion (55), and a groove shoulder located on both axial sides of the groove portion (57). Part (58),
On the outer periphery of the reverse ruled line ring (64) on the front liner (1) side, there are a convex portion (65) continuous in the circumferential direction and concave portions (66) located on both sides in the axial direction of the convex portion (65). Provided on the outer periphery of the reverse crease ring (63) on the back liner (2) side is a groove portion (67) facing the convex portion (65), and a groove shoulder located on both axial sides of the groove portion (67). Part (68),
In the pair of normal ruled ring (53, 54) and the pair of reverse ruled ring (63, 64), the position of the convex portion (55) of the normal ruled ring (53) on the back liner (2) side is set. Corresponding to the position of one groove shoulder (68) of the reverse ruled line ring (63) on the back liner (2) side, and the convex part (65 of the reverse ruled line ring (64) on the front liner (1) side ) Is arranged so as to correspond to the position of one groove shoulder (58) of the normal ruled line ring (54) on the front liner (1) side,
The corrugated cardboard sheet (43) is sandwiched between the convex part (55) of the normal ruled line ring (53) on the back liner (2) side and the groove part of the normal ruled line ring (54) on the front liner (1) side. To form the normal ruled line (15),
Between the groove (67) of the reverse crease ring (63) on the back liner (2) side and the convex part (65) of the reverse crease ring (64) on the front liner (1) side, the corrugated sheet (43) To form the reverse ruled line (16),
Between the groove shoulder (68) of the reverse crease ring (63) on the back liner (2) side and the recess (66) of the reverse crease ring (64) on the front liner (1) side, the corrugated sheet (43 ) To form the weak ruled line (24).   The corrugated cardboard sheet (43) between the recess (56) of the normal crease ring (53) on the back liner (2) side and the groove shoulder (58) of the normal crease ring (54) on the front liner (1) side. ) Is formed to form a weak reverse ruled line (25), and the weak reverse ruled line (25) and the normal ruled line (15) on the opposite side of the reverse ruled line (16) sandwiching the normal ruled line (15) The method for forming a ruled line on a corrugated cardboard sheet according to claim 3, wherein the ruled line is a weak ruled line recessed in parallel on the front liner (1) side. A cardboard sheet (43) 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) recessed on the liner (2) side, a groove-like reverse ruled line (16) recessed on the front liner (1) side in parallel to the normal ruled line (15), and the reverse ruled line (16 ) On the opposite side of the normal ruled line (15), the weak ruled line (24) in which the back liner (2) side is recessed in parallel to the reverse ruled line (16), and the reverse ruled line ( 16) a method for forming a ruled line on a corrugated cardboard sheet, wherein a weak reverse ruled line (25) having a concave on the side of the front liner (1) is formed in parallel to the normal ruled line (15) on the opposite side of 16),
A pair of special crease rings (88, 89) disposed on the back liner (2) side and the front liner (1) side of the cardboard sheet are used, and the pair of special crease rings (88, 89) A method for forming a ruled line of a corrugated cardboard sheet, wherein the normal ruled line (15), the reverse ruled line (16), the weak ruled line (24), and the weak reverse ruled line (25) are simultaneously formed by sandwiching the cardboard sheet (43). A cardboard sheet (43) 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) recessed on the liner (2) side, a groove-like reverse ruled line (16) recessed on the front liner (1) side in parallel to the normal ruled line (15), and the reverse ruled line (16 ) On the opposite side of the normal ruled line (15) sandwiching the weak ruled line (24) recessed in the back liner (2) side in parallel with the reverse ruled line (16),
A pair of normal ruled line rings (53, 54) that sandwich the cardboard sheet, and a pair of normal ruled line rings (53, 54) that sandwich the cardboard sheet (43) at a position shifted upstream or downstream of the pair of normal ruled line rings (53, 54). A pair of reverse crease rings (63, 64);
On the outer periphery of the regular ruled ring (53) on the back liner (2) side, there are a convex portion (55) continuous in the circumferential direction and concave portions (56) located on both sides in the axial direction of the convex portion (55). Provided on the outer periphery of the normal ruled ring (54) on the side of the front liner (1) is a groove portion (57) facing the convex portion (55), and a groove shoulder located on both axial sides of the groove portion (57). Part (58),
On the outer periphery of the reverse ruled line ring (64) on the front liner (1) side, there are a convex portion (65) continuous in the circumferential direction and concave portions (66) located on both sides in the axial direction of the convex portion (65). Provided on the outer periphery of the reverse crease ring (63) on the back liner (2) side is a groove portion (67) facing the convex portion (65), and a groove shoulder located on both axial sides of the groove portion (67). Part (68),
In the pair of normal ruled ring (53, 54) and the pair of reverse ruled ring (63, 64), the position of the convex portion (55) of the normal ruled ring (53) on the back liner (2) side is set. Corresponding to the position of one groove shoulder (68) of the reverse ruled line ring (63) on the back liner (2) side, and the convex part (65 of the reverse ruled line ring (64) on the front liner (1) side ) Is arranged so as to correspond to the position of one groove shoulder (58) of the normal ruled line ring (54) on the front liner (1) side,
The pair of normal ruled ring (53, 54) includes a convex portion (55) of the normal ruled ring (53) on the back liner (2) side and a normal ruled ring (54) on the front liner (1) side. The normal ruled line (15) is formed by sandwiching the corrugated cardboard sheet (43) between the groove (57),
The pair of reverse crease rings (63, 64) is formed by projecting the groove (67) of the reverse crease line (63) on the back liner (2) side and the reverse crease ring (64) on the front liner (1) side. The reverse ruled line (16) is formed by sandwiching the corrugated cardboard sheet (43) with the part (65), and the groove shoulder (68) of the reverse ruled line ring (63) on the back liner (2) side A cardboard sheet ruled line forming device that forms the weak ruled line (24) by sandwiching the cardboard sheet (43) between the concave liner (66) of the reverse ruled line ring (64) on the front liner (1) side.   The pair of normal ruled ring (53, 54) includes a recess (56) of the normal ruled ring (53) on the back liner (2) side and a groove of the normal ruled ring (54) on the front liner (1) side. A weak reverse ruled line (25) is formed by sandwiching the corrugated cardboard sheet (43) between the shoulder part (58), and the weak reverse ruled line (25) is the reverse ruled line (25) sandwiching the normal ruled line (15) ( The cardboard sheet ruled line forming device according to claim 6, wherein the cardboard sheet is formed with a weak ruled line on the opposite side of 16) in parallel with the normal ruled line (15) and recessed on the front liner (1) side.   The pair of normal ruled line rings (53, 54) and the pair of reverse ruled line rings (63, 64) form the normal ruled line (15) on a corrugated cardboard sheet (43) continuous in a strip shape in the middle of the corrugating machine. The ruled line forming apparatus for corrugated cardboard sheets according to claim 6 or 7, which is provided as a part of the scorer (41).   The pair of normal ruled line rings (53, 54) and the pair of reverse ruled line rings (63, 64) are provided as part of a cutting machine for cutting a sheet of corrugated cardboard sheets (43) to a predetermined width. The corrugated line forming apparatus for corrugated cardboard sheets according to claim 6 or 7. A cardboard sheet (43) 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) recessed on the liner (2) side, a groove-like reverse ruled line (16) recessed on the front liner (1) side in parallel to the normal ruled line (15), and the reverse ruled line (16 ) On the opposite side of the normal ruled line (15), the weak ruled line (24) in which the back liner (2) side is recessed in parallel to the reverse ruled line (16), and the reverse ruled line ( 16) a cardboard sheet ruled line forming device for forming a weak reverse ruled line (25) recessed in the front liner (1) side in parallel with the normal ruled line (15) on the opposite side of 16),
The cardboard sheet has a pair of special ruled line rings (88, 89) disposed on the back liner (2) side and the front liner (1) side, and the pair of special ruled line rings (88, 89) A cardboard sheet ruled line forming apparatus for simultaneously forming the normal ruled line (15), the reverse ruled line (16), the weak ruled line (24), and the weak reverse ruled line (25) by sandwiching the cardboard sheet (43).

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