JP7493759B2 - Cushioning material manufacturing equipment - Google Patents

Description

This invention relates to cushioning materials used in packaging and wrapping, and more specifically to a manufacturing device for sheet-shaped cushioning materials that are stretched before use.

An example of the aforementioned cushioning material is described in Patent Document 1 below. This cushioning material is formed by arranging many slits that extend in one direction in a paper sheet. Specifically, many slit rows are arranged in a straight line with slit sections and non-slit sections vertically alternating, and when arranged in rows, the middle positions of the slit sections in one slit row are lined up with the middle positions of the non-slit sections in the adjacent slit row. In other words, the slit sections of the slit rows open when pulled.

There are two types of cushioning materials: vertically slit paper and horizontally slit paper. Horizontally slit paper has a row of slits that run in the width direction of the cushioning material, perpendicular to the longitudinal direction of the cushioning material. Vertically slit paper, unlike horizontally slit paper, has a row of slits that run in the longitudinal direction of the cushioning material.

All of these cushioning materials are stretched in the normal direction to the slit rows to form the slits into a roughly honeycomb shape before use, but horizontally slit paper is the mainstream due to the ease of stretching.

In the manufacture of cushioning material, the base sheet, which is the material for the cushioning material, is conveyed while being sandwiched between a cutter roller and anvil roller, and cutting pressure is applied by the slit forming blade of the cutter roller to form slits in the base sheet. The cushioning material with the slits is then wound up for use.

Japanese Patent Application Laid-Open No. 1-226574

However, when winding the sheet, it is necessary to apply winding tension. To obtain a better winding condition, it is generally necessary to appropriately change the winding tension according to the winding diameter. However, with the horizontally slit paper mentioned above, the normal direction of the slit row (the direction in which it is stretched during use) is the same as the conveying direction, so winding tension cannot be applied. For this reason, the horizontally slit paper wound into a roll is loose, and it is not possible to obtain a winding condition suitable for carrying and handling.

In the case of vertically slit paper, the normal direction of the slit rows (the direction in which it is stretched when used) and the conveying direction are perpendicular to each other, so it is possible to apply winding tension. However, because the direction in which it is stretched when used and the conveying direction are perpendicular to each other, it is difficult to automatically stretch it to create a three-dimensional shape while conveying it.

Therefore, the main objective of this invention is to provide a method for obtaining a proper winding state for a cushioning material with slits, and to enable it to be rolled up into a three-dimensional shape even while being transported.

The means for this purpose is a cushioning material manufacturing device that includes a base sheet supplying section that supplies a base sheet, a slit forming section that has a cutter roller and forms a group of slits arranged so that the slits open when a slit line having linear slit portions and non-slit portions is pulled, and a winding section that winds up the cushioning material with the group of slits formed, in which the flow direction of the slit forming blade of the cutter roller is inclined with respect to the width direction of the base sheet perpendicular to the conveying direction of the base sheet, the flow direction of the slit forming blade of the cutter roller is inclined with respect to the width direction of the base sheet perpendicular to the conveying direction of the base sheet, and the distance between the rollers provided downstream of the cutter roller is set to be equal to or less than a unit length equivalent to the length in the conveying direction of a virtual unit area that forms a square in a plan view with a diagonal line extending obliquely from one side to the other side in the width direction of the cushioning material.

In this configuration, the slit forming blade of the cutter roller forms a slit section inclined in the width direction of the base sheet. After the slit is formed, the rollers spaced apart by a distance equal to or less than the unit length transport the cushioning material in the form of a base sheet without deforming the slit section, and the winding section winds it up with the desired winding tension.

This invention forms a group of slits with diagonal slit lines, and sets the distance between the rollers to a distance that allows tension to be applied, so that an appropriate winding state can be obtained and it is possible to form the film into a three-dimensional shape even while it is being transported.

FIG. FIG. Plan view of cushioning material and three-dimensional cushioning material. FIG. FIG. FIG. Table showing test results. FIG.

One embodiment of the invention is described below with reference to the drawings.

Figure 1 shows a schematic plan view of the cushioning material manufacturing device 11, and Figure 2 shows its side view. As shown in these figures, the cushioning material manufacturing device 11 is used to manufacture cushioning material 12 as shown in Figure 3(a), and mainly has a base sheet supply section 13, a slit forming section 14, and a winding section 15.

First, we will explain the cushioning material 12, and then we will explain the structure of the cushioning material manufacturing device 11.

As shown in an enlarged view of a portion of FIG. 3(a), the cushioning material 12 is configured with a large number of slit sections 21 extending in one direction arranged in a staggered pattern. The slit sections 21 are cuts that penetrate in the thickness direction. The slit sections 21 and non-slit sections 22 of the slit lines 23 are each formed to a predetermined length, and a large number of the slit lines 23 are arranged side by side at regular intervals. When arranged side by side, the slit lines 23 are arranged so that the intermediate positions of the slit sections 21 and non-slit sections 22 of adjacent slit lines 23 are aligned in the normal direction of the slit lines 23.

Since this type of cushioning material 12 only has slits 21, it is simply a sheet and does not have much cushioning effect. However, when it is stretched in a direction perpendicular to the longitudinal direction of the slit lines 23 (normal direction) to expand the slits 21 and create a three-dimensional cushioning material 12b, roughly honeycomb-shaped openings 24 are formed, as shown in the enlarged partial view of Figure 3(b). Figure 4 is an explanatory diagram showing the change in shape. The parts that form these openings 24, i.e., the parts other than the slits 21, are inclined diagonally relative to the surface direction of the cushioning material 12, resulting in a structure that exerts a cushioning effect.

The base sheet supply section 13 of the cushioning material manufacturing device 11 is a section that supplies the base sheet 12a, which is the material of the cushioning material 12, and holds the base sheet 12a, which is made of an appropriate material such as craft paper or a resin sheet and is wound into a roll, so that it can be pulled out by a support roller 31. A feed roller 32 connected to a motor is provided at the feed position of the base sheet 12a.

The slit forming section 14 has a cutter roller 41 and an anvil roller 42, and a slit forming blade 41a is formed on the outer circumferential surface of the cutter roller 41. A motor is connected to the cutter roller 41.

The slit forming blade 41a forms the slit group as described above. A slit group is a vertical slit line 23 in which linear slit sections 21 and non-slit sections 22 are arranged so that the slit sections 21 open when pulled.

A passive roller, the supply side hug roller 43, is provided in front of the slit forming section 14, and a passive roller, the discharge side hug roller 44, is provided in the rear of the slit forming section 14, so that an appropriate tension can be applied when the cutter roller 41 forms the slit. A nip roller 45 is provided opposite the supply side hug roller 43 and the discharge side hug roller 44 to sandwich the base sheet 12a or the cushioning material 12.

The winding section 15 is composed of a winding roller 51 provided after the discharge side hugging roller 44. The winding roller 51 winds up the cushioning material 12 in which the slits are formed, and is connected to a motor. Just before the winding section 15, there is a tension roller 52 that applies tension during winding, an upstream guide roller 53 provided before the tension roller 52, and a downstream guide roller 54 provided after it. The roller provided opposite the tension roller 52 is a nip roller 52a.

The rotation of the motors (not shown) connected to the feed roller 32, cutter roller 41, tension roller 52, and take-up roller 51 is controlled by a control unit (not shown).

In a cushioning material manufacturing device 11 having such a general structure, the flow direction Y of the slit forming blade 41a of the cutter roller 41 is inclined at an appropriate angle with respect to the width direction of the base sheet 12a, which is perpendicular to the conveying direction (longitudinal direction) X of the base sheet 12a, as shown in FIG. 1.

That is, the slit forming blade 41a of the cutter roller 41 has a structure in which a large number of individual blade tips that form the slit portion 21 are arranged in a straight line and are intermittently arranged, and the flow direction Y of the slit forming blade 41a, i.e., the direction in which the blade tips are consecutively and intermittently arranged, is inclined at a desired inclination angle θ from a direction perpendicular to the conveying direction X. This desired inclination angle θ is 0°<θ<90°.

In the example of FIG. 1, the axial direction of the cutter roller 41 is the same as the width direction of the base sheet 12a, which is perpendicular to the conveying direction X of the base sheet 12a. Therefore, the flow direction Y of the slit forming blade 41a is also inclined from the axial direction of the cutter roller 41 by the same desired inclination angle θ as described above.

The slit forming blade 41a can be formed to a length equal to or greater than the width of the base sheet 12a, so that the slit line 23 is formed over the entire length from one side of the base sheet 12a to the other side, exposing the slit portion 21 at the end. However, as shown in FIG. 1, it is preferable to set the forming range of the slit forming blade 41a to a range equal to or less than the width of the base sheet 12a, so that the length allows for the provision of ear portions 25 (see FIG. 3(a)) of appropriate width without the slit portion 21 on one and the other sides. This is because it is possible to prevent the end from being torn during handling after winding, etc.

In addition, in the cushioning material manufacturing device 11, the distance between the rollers provided downstream from the cutter roller 41 (the distance between the points on the base sheet 12a or the cushioning material 12 that contact the rollers) is set to be equal to or less than the unit length Ls.

As shown in FIG. 5, the unit length Ls is a length equivalent to the length in the transport direction X of a virtual unit area S that is a square in plan view with a diagonal line of a single slit line 23 that extends diagonally from one side to the other in the width direction of the cushioning material 12. This is a reference length for a cushioning material 12 that has a diagonally extending slit portion 21. Specifically, when focusing on one slit line 23 that extends from one side to the other in the width direction among the multiple slit lines 23 formed in the cushioning material 12, the unit length Ls is the length W×tan θ in the transport direction X of the unit area S that is sandwiched between the virtual lines that have the slit line 23 as a diagonal line.

The above-mentioned "from one side to the other side in the width direction of the cushioning material 12" means a position inside the end in the case of cushioning material 12 having ears 25 as described above. Therefore, strictly speaking, the unit length Ls will differ depending on the length of the slit line 23 even for cushioning materials 12 having slit lines 23 of the same inclination. However, whether or not the slit portion 21 of the cushioning material 12 deforms depends more on the inclination angle of the slit line 23 than on the difference in the length of the slit line 23 due to the presence or absence of ears 25, so the strict difference in the length of the slit line 23 can be ignored. Therefore, the unit length Ls can be considered to be W x tan θ.

As shown in Figs. 1 and 2, the rollers provided in the rear stages from the cutter roller 41 are, in order from the front stage in the conveying direction X, the cutter roller 41, the discharge side embrace roller 44, the upstream guide roller 53, the tension roller 52, the downstream guide roller 54, and the take-up roller 51. Therefore, the distance Lout between the cutter roller 41 and the discharge side embrace roller 44, the distance L1 between the discharge side embrace roller 44 and the upstream guide roller 53, the distance L2 between the upstream guide roller 53 and the tension roller 52, the distance L3 between the tension roller 52 and the downstream guide roller 54, and the distance L4 between the downstream guide roller 54 and the take-up roller 51 are less than the unit length Ls. In other words, all of the distances Lout, L1, L2, L3, and L4 are equal to or shorter than the length of W x tan θ. The distance Lstr between the discharge side embrace roller 44 and the take-up roller 51 may be less than the unit length Ls.

Specifically, as shown in FIG. 5, when the width of the cushioning material 12 is W and the angle between the direction perpendicular to the conveying direction X and the slit line 23 is θ, the unit length is W × tan θ. For example, when θ is 45 degrees, tan θ is 1, so the unit length Ls is the same as the width W of the cushioning material 12.

The drive control of each roller, particularly the rotation conditions (rotation speed and torque) of the tension roller 52 and the winding roller 51, are set based on the tensile characteristics of the cushioning material 12 obtained as follows.

The tensile properties of the cushioning material 12 are obtained by a tensile test to confirm the behavior of the cushioning material 12 when pulled. This test is in accordance with JIS-P8113 (Paper and cardboard - Test methods for tensile properties - Part 2: Constant speed extension method).

The test equipment used was a computer-aided tensile tester, model HY-205CS, manufactured by Shanghai Heng Yu Instrument Co., Ltd.

The test piece was a 70 g/m ² , 110 μm thick craft paper with a slit group with a slit portion 21 length of 10 mm, a non-slit portion 22 length of 3 mm, and a normal interval along the slit line 23 of 2 mm. Nine types of inclination angles of the slit line 23 were prepared. That is, as shown in FIG. 6, the inclination angle θ between the direction perpendicular to the conveying direction X and the slit line 23 was 90°, which was designated as sample <1>, followed by 71.6°, 63.4°, 56.3°, 45°, 26.6°, 14°, 5.7°, and 0°, which was designated as sample <2>, sample <3>, sample <4>, sample <5>, sample <6>, sample <7>, sample <8>, and sample <9>, respectively. Sample <1> is a so-called vertical slit paper, and sample <9> is a horizontal slit paper.

The width W of the test pieces was 50 mm in both cases, and there were two types of gripping interval L, 50 mm and 100 mm. [Test 1] was the one with gripping interval L of 50 mm, and [Test 2] was the one with gripping interval L of 100 mm.

The pulling speed was 20 mm/min.

The test results are shown in the table in Figure 7. The results shown in the table are the average values of the results obtained by carrying out multiple tests using five or more test pieces for each test.

As can be seen from the table in Figure 7, no yield point was observed when the value of W x tan θ was equal to or less than the unit length Ls. That is, in [Test 1], the slit portion 21 did not open for samples <1> to <5>, and in [Test 2], the slit portion 21 did not open for samples <1> to <3>.

In addition, for the cushioning material 12 made of kraft paper as described above and having the slit group as described above, the tensile force at which the slit portion 21 first opens can be estimated to be approximately 0.85 N/50 mm (17 N/m) based on the results of sample <9>.

Furthermore, it can be seen that as the inclination angle increases, the pulling tension required to open the slit portion 21 increases. Conversely, the larger the inclination angle, the less the slit portion 21 opens even when tension is applied.

Based on the test results, the control unit that drives and controls each roller sets the drive conditions according to the inclination angle θ so that drive control is performed to obtain the pulling force required for transport and winding. The pulling force is set with reference to a value obtained by multiplying the pulling tension (e.g., 0.85 N/50 mm (17 N/m)) at which the slit section 21 first opens in the case of horizontally slit paper with an inclination angle of 0° by 1/cos θ, so that the slit section 21 does not open even when tension is applied during transport and winding.

In the cushioning material manufacturing device 11 configured as described above, the slit line 23, in which the slit portion 21 and the non-slit portion 22 are aligned vertically, is formed at an angle with respect to the width direction of the base sheet 12a, which is perpendicular to the conveying direction of the base sheet 12a, to obtain the cushioning material 12. Thereafter, when conveying and winding the cushioning material 12, rollers are used that are spaced apart at an interval equal to or less than the unit length Ls, which corresponds to the length in the conveying direction of a virtual unit area S that is a square in plan view and has a diagonal line of one slit line 23 that extends obliquely from one side to the other in the width direction of the cushioning material 12, to perform the cushioning material manufacturing method.

First, the base sheet 12a sent out from the base sheet supply section 13 is slit by the cutter roller 41 rotating at a constant peripheral speed. At this time, tension is applied to the base sheet 12a by the supply side hugging roller 43 and the discharge side hugging roller 44. The slit section 21 is formed at a desired angle inclined with respect to the width direction of the base sheet 12a (cushion material 12) according to the inclination angle θ of the slit forming blade 41a of the cutter roller 41 (see Figure 3(a) and Figure 5).

When forming the slits, the slit forming blade 41a of the cutter roller 41 does not strike the anvil roller 42 in a line as in the case of forming horizontally slit paper, but strikes it at a point. This allows the required cutting pressure to be reduced, and stable cutting performance can be obtained even when the slit forming work is performed at high speed.

Stable cutting can also be achieved by setting the distance between the cutter roller 41 and the discharge side support roller 44 to less than the unit length Ls. In other words, the slits can be formed under high tension close to the strength limit of the cushioning material 12, so the slits 21 are formed properly.

In addition, the direction in which the slits 21 are arranged is oblique to the longitudinal direction of the cushioning material 12, so unlike the case of vertically slit paper, it is possible to make the cushioning material 12 three-dimensional even while it is being transported.

The cushioning material 12 with the slits 21 formed continues to be transported and wound up by the winding roller 51, but the rollers that support and transport the cushioning material 12 from the cutter roller 41 until it is wound up by the winding roller 51 are all arranged in parallel, and the spacing between them is less than or equal to the unit length Ls. Therefore, as mentioned above, it is possible to apply tension close to the strength limit of the cushioning material 12.

The cushioning material 12 is transported and wound without the slit section 21 being deformed. During winding, the control unit controls the rotation speed and torque of each roller, and the motor drive conditions are changed according to the winding diameter to perform a winding operation that increases the winding tension at the beginning and end of winding.

In this way, because the spacing between the rollers is set to less than the unit length Ls, transport and winding can be performed without deforming the slit portion 21 even when high tension is applied, so winding with the necessary tension is possible, resulting in a winding state suitable for transport and handling. Because a good winding state is obtained, tasks such as packaging can be performed smoothly using the cushioning material 12 wound into a roll.

Other examples will be described below. In this description, the same parts as those in the configuration described above will be given the same reference numerals and detailed description will be omitted.

Figure 8 shows another example of the rear stage of the base sheet supply unit 13. That is, a stacking unit 16 is provided in front of the slit forming unit 14, which stacks the transported base sheet 12a into multiple sheets.

As mentioned above, the cutting by the slit forming blade 41a of the cutter roller 41 can be done at points, so the cutting pressure can be reduced compared to when forming horizontally slit paper, but a certain degree of cutting pressure is still necessary. Therefore, tension must be applied to the base sheet 12a when forming the slits, and a base sheet 12a with low tensile strength may break when the slits are formed or during subsequent transport.

Therefore, in the example shown in Figure 8, the base sheet 12a is folded and overlapped along a fold line extending in the conveying direction so that its strength can be maintained during slit formation and subsequent conveying.

The overlapping portion 16 can be constructed by arranging a typical triangular plate 61. The cushioning material 12 can be folded in half vertically to make it double-layered, or folded in half again vertically to make it quadruple-layered.

In a cushioning material manufacturing device 11 with such a stacking section 16, slit formation and transport can be performed reliably even on base material sheets 12a that do not have high strength.

In the above example, the supply side holding roller 43 and the discharge side holding roller 44 are passive rollers, but they may be driven rollers.

REFERENCE SIGNS LIST 11... Cushioning material manufacturing device 12... Cushioning material 12a... Base sheet 13... Base sheet supply section 14... Slit forming section 15... Winding section 16... Overlapping section 21... Slit section 22... Non-slit section 23... Slit line 41... Cutter roller 41a... Slit forming blade 44... Discharge side hugging roller 51... Winding roller Ls... Unit length X... Conveying direction Y... Flow direction of slit forming blade

Claims (3)

A cushioning material manufacturing device including a base sheet supplying section that supplies a base sheet, a slit forming section that has a cutter roller and forms a group of slits arranged such that a slit line in which linear slit portions and non-slit portions are vertically arranged opens when the slit portions are pulled, and a winding section that winds up the cushioning material in which the group of slits has been formed,
a flow direction of a slit forming blade of the cutter roller is inclined with respect to a width direction of the base sheet perpendicular to a conveyance direction of the base sheet,
A roller for applying tension to the base sheet in the slit forming section is disposed in front of and behind the slit forming section,
A cushioning material manufacturing device in which the distance between the cutter roller and one of these rollers , which is provided downstream of the cutter roller, is set to be less than a unit length corresponding to the length in the conveying direction of a virtual unit area which, in a plan view, forms a square with a diagonal line extending diagonally from one side to the other in the width direction of the cushioning material. 2. The cushioning material manufacturing apparatus according to claim 1, further comprising a stacking section, which stacks the transported base sheet into a plurality of sheets, upstream of the slit forming section. A method for manufacturing a cushioning material, comprising the steps of: forming a group of slits in a base sheet that is supplied with a cutter roller, the group of slits being arranged such that a slit line, in which linear slit portions and non-slit portions are arranged vertically, is pulled to open the slit portions; and then winding up the cushioning material with the group of slits formed therein,
a roller is provided in front of and behind the cutter roller, and the distance between the rear roller and the cutter roller is set to be equal to or less than a unit length corresponding to a length in a conveying direction of a virtual unit area in a rectangular shape in a plan view, the diagonal of which is one of the slit lines extending obliquely from one side to the other side in the width direction of the cushioning material ;
The slit lines are formed in a manner inclined with respect to a width direction of the base sheet perpendicular to a conveying direction of the base sheet, and tension is applied to the base sheet , and the base sheet is then wound up.
Cushioning material manufacturing method.

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