CUSHIONING MATERIAL, PACKAGING MATERIAL, AND PACKAGED ITEM

Abstract

A cushioning material cushions an external force applied to an electronic device. The cushioning material includes a support plate and a cushioning portion. The support plate is a member configured to support the electronic device. The cushioning portion is included in the support plate and cushions an external force applied to the electronic device. The cushioning portion includes a first cushioning portion and a second cushioning portion. The first cushioning portion has a first surface fixed to the support plate and a second surface facing the electronic device. The second cushioning portion has a third surface fixed to the support plate and a fourth surface facing the electronic device. In a graph where the vertical axis represents the external force applied to the electronic device and the horizontal axis represents the time since the external force starts to be applied to the electronic device, the types of waveforms of the graph of the first cushioning portion and the second cushioning portion are different.

Claims

1. A cushioning material configured to cushion an external force applied to an electronic device, the cushioning material comprising: a support plate configured to support the electronic device; and a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device, the cushioning portion including: a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device; and a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein in a graph in which a vertical axis represents an external force applied to the electronic device and a horizontal axis represents time from when the external force starts to be applied to the electronic device, types of waveforms of the graph are different between the first cushioning portion and the second cushioning portion.

2. The cushioning material according to claim 1, wherein the first cushioning portion and the second cushioning portion are arranged in contact with each other.

3. The cushioning material according to claim 1, wherein any one of the first cushioning portion and the second cushioning portion is arranged so as to be surrounded by the other one of the first cushioning portion and the second cushioning portion.

4. The cushioning material according to claim 2, wherein the second surface and the fourth surface are flush with each other.

5. The cushioning material according to claim 1, wherein the first cushioning portion includes a material of which the waveform is a trapezoidal wave, and the second cushioning portion includes a material of which the waveform is a half-sine wave.

6. The cushioning material according to claim 1, wherein a material of the first cushioning portion is a corrugated cardboard material, and the second cushioning portion is made of a foamed resin material.

7. A cushioning material configured to cushion an external force applied to an electronic device, the cushioning material comprising: a support plate configured to support the electronic device, and a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device, the cushioning portion including: a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device; and a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein in a stress-strain diagram where a vertical axis represents compressive stress applied to the cushioning portion and a horizontal axis represents strain applied to the cushioning portion, (a) maximum stress in an elastic region of the first cushioning portion is larger than maximum stress in an elastic region of the second cushioning portion, (b) a slope indicating a ratio of stress with respect to strain in a plastic region of the first cushioning portion takes a value of zero or close to zero, and a slope indicating a ratio of stress with respect to strain in a plastic region of the second cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion, and (c) maximum stress in an elastic region of a composite cushioning portion configured by arranging the first cushioning portion and the second cushioning portion in parallel in a direction facing the electronic device is larger than the maximum stress of the second cushioning portion, and the slope in the plastic region of the composite cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion.

8. The cushioning material according to claim 7, wherein the first cushioning portion is made of a corrugated cardboard material, and the second cushioning portion is made of a foamed resin material.

9. The cushioning material according to claim 1, wherein the electronic device is a recording device.

10. A packaging material comprising: a packaging box configured to accommodate the electronic device; and the cushioning material according to claim 1.

11. A packaged item comprising: the packaging material according to claim 10; and the electronic device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is an exploded perspective view illustrating an example of a configuration of a packaging material in a first embodiment.

[0010] FIG. 2 is a perspective view illustrating an example of a structure of a cushioning material.

[0011] FIG. 3 is a perspective view illustrating a cushioning portion.

[0012] FIG. 4 is a side cross-sectional view of the cushioning portion taken along a plane orthogonal to a fixed surface.

[0013] FIG. 5 is a graph showing a stress-strain diagram when a corrugated cardboard material is compressed.

[0014] FIG. 6 is a graph showing a stress-strain diagram when a foamed resin material is compressed.

[0015] FIG. 7 is a graph showing a stress-strain diagram when a composite cushioning portion is compressed.

[0016] FIG. 8 is a graph showing a relationship between acceleration applied to an electronic device via the corrugated cardboard material and time.

[0017] FIG. 9 is a graph showing a relationship between acceleration applied to the electronic device via the foamed resin material and time.

[0018] FIG. 10 is a graph illustrating a relationship between acceleration applied to the electronic device via the composite cushioning portion and time.

[0019] FIG. 11 is a perspective view illustrating a cushioning material of a second embodiment.

[0020] FIG. 12 is a side cross-sectional view illustrating a cross section of the cushioning material.

[0021] FIG. 13 is a perspective view illustrating a cushioning material of a third embodiment.

[0022] FIG. 14 is a side cross-sectional view illustrating a cross section of the cushioning material.

DESCRIPTION OF EMBODIMENTS

[0023] Hereinafter, an embodiment of a packaged item and a cushioning material will be described with reference to FIGS. 1 to 10. First, an overall outline of the packaged item and a packaging material will be described with reference to FIG. 1.

Overall Outline of Packaged Item and Packaging Material

[0024] FIG. 1 is an exploded perspective view illustrating an example of the configurations of a packaged item 10 and a packaging material 20. The packaged item 10 includes the packaging material 20 and an electronic device 100. The packaged item 10 is configured by packaging the electronic device 100 with the packaging material 20.

[0025] The packaging material 20 includes a cushioning material 40 configured to cushion an external force applied to the electronic device 100. The packaging material 20 may include a packaging box 30 configured to accommodate the electronic device 100, and the cushioning material 40. The packaging box 30 includes a body 31 having a bottomed box shape including an opening 33 opened upward, and four flaps 32 extending from four sides surrounding the opening 33 of the body 31.

[0026] As illustrated in FIG. 1, the cushioning material 40 is interposed between the packaging box 30 and the electronic device 100. That is, the electronic device 100 is accommodated in the packaging box 30 via the cushioning material 40. The packaging material 20 may include a plurality of the cushioning materials 40. The electronic device 100 is accommodated in the packaging box 30 in a state of being protected by the plurality of cushioning materials 40. The plurality of cushioning materials 40 are arranged so as to surround the electronic device 100. In the example illustrated in FIG. 1, the electronic device 100 has a cuboid shape, for example. The electronic device 100 having a cuboid shape has four corner portions (corners) at parts of four sides parallel to one another. In the example illustrated in FIG. 1, four cushioning materials 40 are arranged at the four corner portions of the electronic device 100.

[0027] The cushioning material 40 includes a cushioning portion 50 configured to cushion an external force (impact force) applied to the electronic device 100 accommodated in the packaging box 30. The packaged item 10 receives an external force (impact force) due to an impact when a worker erroneously drops the packaged item 10 during sorting work, loading work, conveyance, or the like, or an impact caused by shaking, vibration, or the like during conveyance. The cushioning material 40 protects the electronic device 100 from this type of external force.

[0028] Here, the electronic device 100 is, for example, a recording device 110. The recording device 110 is an inkjet printer or the like. However, the recording device 110 is not limited to, for example, an inkjet printer, and may be a laser printer, a dot impact printer, or the like. The recording device 110 may be a printer dedicated to recording, or may be a multifunction peripheral having both a recording function and other functions. The other functions of the multifunction peripheral include a scanner function, a copy function, and a facsimile function. In the present embodiment, as the electronic device 100, a device other than the recording device 110, such as a scanner, a television, a refrigerator, a washing machine, a microwave oven, or a personal computer may be adopted.

[0029] The example illustrated in FIG. 1 assumes that the packaging material 20 includes four cushioning materials 40A to 40D. The electronic device 100 and the four cushioning materials 40A to 40D are accommodated in the packaging box 30 from the opening 33. That is, the electronic device 100 in which four sites (four corner portions) of upper, lower, left, and right are protected by the four cushioning materials 40 illustrated in FIG. 1 is accommodated in the packaging box 30. Thereafter, the opening 33 of the packaging box 30 is closed by the four flaps 32. The four flaps 32 are held in a closed state by an adhesive tape or an adhesive. This provides the packaged item 10. In the packaged item 10, the electronic device 100 is protected by the four cushioning materials 40A to 40D interposed between the electronic device 100 and the packaging box 30. The electronic device 100 faces the cushioning portion 50 included in the four cushioning materials 40A to 40D.

[0030] Hereinafter, for convenience of description, a packaging box coordinate system fixed to the packaging box 30 is introduced. The packaging box coordinate system is a three-axis coordinate system having an XW axis, a YW axis, and a ZW axis orthogonal to one another. The ZW axis extends in a ZW direction, which is a direction from the opening 33 of the packaging box 30 toward a bottom surface. The XW axis extends in an XW direction orthogonal to the ZW direction. The YW axis extends in a YW direction orthogonal to the ZW direction and the XW direction. Note that the XW axis, the YW axis, and the ZW axis are not limited to being orthogonal to one another, and may be any axes as long as they intersect one another. Hereinafter, a direction opposite to the XW direction is referred to as a XW direction, a direction opposite to the YW direction is referred to as a YW direction, and a direction opposite to the ZW direction is referred to as a ZW direction.

[0031] In the example illustrated in FIG. 1, the electronic device 100 is protected at four sites by the four cushioning materials 40A to 40D. The cushioning material 40A protects the lower left end portion of the electronic device 100 in the ZW direction and the XW direction. The cushioning material 40B protects the lower right end portion of the electronic device 100 in the ZW direction and the +XW direction. The cushioning material 40C protects the upper left end portion of the electronic device 100 in the ZW direction and the XW direction. The cushioning material 40D protects the upper right end portion of the electronic device 100 in the ZW direction and the +XW direction.

[0032] The cushioning material 40A includes a plurality of the cushioning portions 50 facing the electronic device 100 in the ZW direction, the XW direction, the YW direction, and the YW direction. The cushioning material 40B includes the plurality of cushioning portions 50 facing the electronic device 100 in the ZW direction, the XW direction, the YW direction, and the YW direction. The cushioning material 40C includes the plurality of cushioning portions 50 facing the electronic device 100 in the ZW direction, the XW direction, the YW direction, and the YW direction. The cushioning material 40D includes the plurality of cushioning portions 50 facing the electronic device 100 in the ZW direction, the XW direction, the YW direction, and the YW direction. In this manner, all of the plurality of surfaces (six surfaces) forming the outer peripheral surface of the electronic device 100 face at least one cushioning portion 50. In the present embodiment, all of the plurality of surfaces (six surfaces) forming the outer peripheral surface of the electronic device 100 face the plurality of cushioning portions 50.

Configuration of Cushioning Material 40 and Cushioning Portion 50

[0033] Hereinafter, an example of the configurations of the cushioning material 40 and the cushioning portion 50 will be described with reference to FIGS. 2 to 4. Note that the four cushioning materials 40A to 40D illustrated in FIG. 1 have the same configurations basically. In the following description, unless otherwise distinguished, the four cushioning materials 40A to 40D are simply referred to as the cushioning material 40.

[0034] As illustrated in FIG. 2, the cushioning material 40 includes a support portion 41 configured to support the electronic device 100 and the cushioning portion 50 configured to cushion an external force applied to the electronic device 100. The cushioning portion 50 is included in the support portion 41. The cushioning material 40 illustrated in FIG. 2 is an example in which the support portion 41 includes the plurality of cushioning portions 50.

[0035] The support portion 41 includes four support plates 42A to 42D. The four support plates 42A to 42D are different from one another in the directions in which the surfaces to which the cushioning portions 50 are fixed face. The support portion 41 has a predetermined shape illustrated in FIG. 2 in which the four support plates 42A to 42D can face four surfaces of a part including two corner portions on both sides of one side of the electronic device 100. The support portion 41 may be formed in the predetermined shape illustrated in FIG. 2 by a plurality of plate members, or may be formed in the predetermined shape illustrated in FIG. 2 by bending one plate material. The support portion 41 may be formed of corrugated cardboard, for example. The corrugated cardboard may be made of paper or may be made of synthetic resin.

[0036] Specifically, the support portion 41 includes two support plates 42A and 42D orthogonal to each other, and two support plates 42B and 42C whose surfaces are orthogonal to the two support plates 42A and 42D, the two support plates 42B and 42C facing each other. The support portion 41 has a predetermined shape in which the four support plates 42A to 42D can face four surfaces of a part including two corner portions on both sides of one side of the electronic device 100 having the cuboid shape.

[0037] Hereinafter, the four support plates 42A to 42D included in the support unit 41 illustrated in FIG. 2 are defined as a first support plate 42A, a second support plate 42B, a third support plate 42C, and a fourth support plate 42D. The first support plate 42A constitutes a bottom surface of the cushioning material 40. The second support plate 42B constitutes a side surface of one of the two side surfaces of the cushioning material 40. The third support plate 42C constitutes a side surface of the other of the two side surfaces of the cushioning material 40. The fourth support plate 42D constitutes a back surface of the cushioning material 40. Note that the present embodiment assumes, as an example, a case where each of the plurality of support plates 42A to 42D constituting the support portion 41 is made of corrugated cardboard.

[0038] In the example illustrated in FIG. 2, two cushioning portions 50 are fixed to the first support plate 42A. One cushioning portion 50 is fixed to the second support plate 42B. One cushioning portion 50 is fixed to the third support plate 42C. Two cushioning portions 50 are fixed to the fourth support plate 42D. Note that the present embodiment is characterized by the configuration of the cushioning portion 50 included in the cushioning material 40.

[0039] Hereinafter, for convenience of description, a cushioning material coordinate system corresponding to a direction facing the electronic device 100 is introduced with respect to each of the cushioning portions 50. Unless otherwise distinguished, the four support plates 42A to 42D included in the cushioning material 40 are simply referred to as the support plate 42.

[0040] FIG. 2 illustrates an X1 axis, a Y1 axis, and a Z1 axis of the cushioning material coordinate system, focusing on the first support plate 42A, which is one plate-shaped portion among the four support plates 42A to 42D. The cushioning material coordinate system is a three-axis coordinate system having the X1 axis, the Y1 axis, and the Z1 axis orthogonal to one another. The X axis extends in an X1 direction. The Y axis extends in a Y1 direction. The Z axis extends in a Z1 direction. The X1 direction, the Y1 direction, and the Z1 direction of the cushioning material coordinate system are a three-axis coordinate system defined for each support plate 42 based on the following definition.

[0041] Here, the Z1 direction is a direction from one surface in contact with the support plate 42 toward the other surface positioned on the opposite side of this one surface among the plurality of surfaces included in the cushioning portion 50. The Z1 direction is a direction orthogonal to the extending direction of the support plate 42. The X1 direction is a direction orthogonal to the Z1 direction and is a direction parallel to the extending direction of the support plate 42. The Y1 direction is a direction orthogonal to the Z1 direction and the X1 direction, and is a direction parallel to the extending direction of the support plate 42. Note that the X axis, the Y axis, and the Z axis may be any axes as long as they intersect one another. Hereinafter, a direction opposite to the X1 direction is referred to as an X2 direction, a direction opposite to the Y1 direction is referred to as a Y2 direction, and a direction opposite to the Z1 direction is referred to as a Z2 direction. The cushioning material coordinate system is set such that the direction of the cushioning portion 50 as viewed from the electronic device 100 (see FIG. 1) is the Z1 direction. Note that the cushioning material coordinate system is set for each cushioning portion 50.

Configuration of Cushioning Material 40

[0042] Next, the configuration of the cushioning material 40 will be described with reference to FIGS. 3 and 4. Hereinafter, one cushioning portion 50 of the plurality of cushioning portions 50 included in the cushioning material 40 will be described. FIG. 3 illustrates a perspective view of the cushioning portion 50. FIG. 4 illustrates a cross section of the cushioning portion 50 taken along a plane orthogonal to a fixed surface 42P of the support plate 42.

[0043] As illustrated in FIGS. 3 and 4, the one cushioning portion 50 is fixed to the fixed surface 42P orthogonal to the Z1 direction in the support plate 42. The cushioning portion 50 includes a first cushioning portion 51 and a second cushioning portion 52. The first cushioning portion 51 and the second cushioning portion 52 are fixed in a state of being arranged in parallel with respect to the fixed surface 42P of the support plate 42.

[0044] The first cushioning portion 51 includes a first surface 61 fixed to the support plate 42 and a second surface 62 facing the electronic device 100. The second cushioning portion 52 includes a third surface 63 fixed to the support plate 42 and a fourth surface 64 facing the electronic device 100. That is, the surface on which the first cushioning portion 51 is fixed to the support plate 42 is the first surface 61. The surface on which the second cushioning portion 52 is fixed to the support plate 42 is the third surface 63. The surface on which the first cushioning portion 51 faces the electronic device 100 is the second surface 62. The surface on which the second cushioning portion 52 faces the electronic device 100 is the fourth surface 64.

[0045] The second surface 62 and the fourth surface 64 may be flush with each other. Since the first cushioning portion 51 and the second cushioning portion 52 are flush with each other, the second surface 62 and the fourth surface 64 can be substantially simultaneously in contact with a surface facing the electronic device 100 when the packaged item 10 drops. For example, the second surface 62 and the fourth surface 64 may be arranged to be flush with each other by making the thickness of the first cushioning portion 51 and the thickness of the second cushioning portion 52 the same.

[0046] As illustrated in FIGS. 3 and 4, the first cushioning portion 51 and the second cushioning portion 52 may be arranged in contact with each other. Furthermore, as illustrated in FIGS. 3 and 4, any one of the first cushioning portion 51 and the second cushioning portion 52 may be arranged with the periphery surrounded by the other. In the cushioning portion 50, any one of the first cushioning portion 51 and the second cushioning portion 52 may have a plate shape of a predetermined shape and the other may have an annular plate shape surrounding the periphery of the one. In the examples illustrated in FIGS. 3 and 4, the first cushioning portion 51 that is an example of the one is arranged with the periphery surrounded by the second cushioning portion 52 that is an example of the other. In the examples illustrated in FIGS. 3 and 4, the predetermined shape is a rectangle. The first cushioning portion 51, which is an example of the one, has a quadrangular plate shape. The second cushioning portion 52, which is an example of the other, has a square annular plate shape surrounding the periphery of the first cushioning portion 51. The predetermined shape may be a circle, a triangle, a pentagon, a hexagon, or the like. Note that the cushioning portion 50 of the present embodiment constitutes a composite cushioning portion 53 in the form of one assembly by arranging the first cushioning portion 51 and the second cushioning portion 52 in parallel in a state of being in contact with each other.

[0047] In the present embodiment, the first cushioning portion 51 is a corrugated cardboard material. The second cushioning portion 52 is a foamed resin material. The corrugated cardboard material may be made of paper or may be made of synthetic resin. The first cushioning portion 51 may be a corrugated cardboard material of the same type as the support portion 41 (support plate 42) or a corrugated cardboard material of a different type from the support portion 41. Here, the type of the corrugated cardboard material refers to a type that defines strength. The strength of the corrugated cardboard material is defined by the structure, the number of layers, and the thickness of the corrugated cardboard sheet constituting the corrugated cardboard material, for example. In this regard, the type of the corrugated cardboard material may be the type of the structure of the corrugated cardboard sheet, the number of layers of the corrugated cardboard sheet, or the type of the thickness (thickness per layer) of the corrugated cardboard sheet.

[0048] As illustrated in FIG. 4, the corrugated cardboard material constituting the first cushioning portion 51 has a multilayer structure in which a plurality of corrugated cardboard sheets 51A are laminated. The corrugated cardboard sheet 51A has a structure in which two liners made of flat paper and a center core made of wavy paper are joined together with an adhesive. The plurality of corrugated cardboard sheets 51A constituting the first cushioning portion 51 have the identical layer structures. The plurality of corrugated cardboard sheets 51A have the identical thicknesses. The corrugated cardboard material constituting the first cushioning portion 51 has a layer structure of two or more layers. The example illustrated in FIG. 4 includes four layers, but may include three layers, five layers, six layers, or seven or more layers. The number of layers of the corrugated cardboard sheet 51A is set according to necessary cushioning characteristics.

[0049] The foamed resin material constituting the second cushioning portion 52 is a foamed material made of a synthetic resin material. The synthetic resin material is, for example, polyethylene (PE). The synthetic resin material may be polybutene (PB), polystyrene (PS), polyurethane (PU), or the like. The foamed resin material may have a foam expansion ratio within a range of, for example, 10 to 80 times. The thickness of the foamed resin material that is the material of the second cushioning portion 52 may be set to the same thickness as the thickness of the corrugated cardboard material determined from the number of layers of the corrugated cardboard sheet 51A.

[0050] The reason for using the first cushioning portion 51 and the second cushioning portion 52 having different types of materials is to obtain cushioning characteristics suitable for protection of the electronic device 100 by configuring the composite cushioning portion 53 in which members made of two types of materials having different cushioning characteristics are combined. In this case, the cushioning characteristics of the composite cushioning portion 53 can be adjusted by adjusting the area ratio between the first cushioning portion 51 and the second cushioning portion 52. That is, the cushioning characteristics of the composite cushioning portion 53 can be adjusted by adjusting the area ratio that is the ratio between the area of the second surface 62 of the first cushioning portion 51 and the area of the fourth surface 64 of the second cushioning portion 52.

[0051] In the examples illustrated in FIGS. 3 and 4, where the second surface 62 and the fourth surface 64 are flush with each other, the thickness of the first cushioning portion 51 and the thickness of the second cushioning portion 52 are the same. The cushioning characteristics of the cushioning portion 50 can be adjusted by adjusting the area ratio between the second surface 62 and the fourth surface 64 while maintaining the condition that the second surface 62 and the fourth surface 64 are flush with each other. In the present embodiment, the area ratio between the second surface 62 of the first cushioning portion 51 and the fourth surface 64 of the second cushioning portion 52 is set to a value at which a cushioning characteristics necessary for protection of the electronic device 100 can be obtained. For example, the area ratio may be determined based on the test results of the drop impact test.

Stress-Strain Diagram

[0052] Next, a stress-strain diagram of the cushioning portion 50 will be described with reference to FIGS. 5 to 7. FIGS. 5 to 7 are stress-strain diagrams when each of the cushioning portions 51, 52, and 53 is applied with an external force (compressive force) in the compression direction. Stress o on the vertical axis is compressive stress. The horizontal axis represents strain . FIG. 5 is a stress-strain diagram of the first cushioning portion 51. That is, FIG. 5 is a stress-strain diagram of a corrugated cardboard material that is a material of the first cushioning portion 51. FIG. 6 is a stress-strain diagram of the second cushioning portion 52. That is, FIG. 6 is a stress-strain diagram of a foamed resin material that is a material of the second cushioning portion 52. FIG. 7 is a stress-strain diagram of the cushioning portion 50. That is, FIG. 7 is a stress-strain diagram of the composite cushioning portion 53 configured by arranging the corrugated cardboard material and the foamed resin material in parallel with respect to the compression direction. Each stress-strain diagram includes a usable region UA and a nonusable region NA. The usable region UA is a region that can be used as a cushioning material. The nonusable region NA is a region that cannot be used as a cushioning material. The nonusable region NA is not considered for the characterization of the cushioning material.

[0053] As shown in FIG. 5, the corrugated cardboard material elastically deforms to maximum stress 1. That is, elastic deformation occurs in an elastic region EA from the compression start point (=0) to the maximum stress 1. In the elastic region EA, the change rate of the stress with respect to the strain is a constant value. In the elastic region EA, a substantially straight line having a constant slope is drawn. In a plastic region PA after reaching the maximum stress 1, the change rate of the stress with respect to the strain is smaller than the change rate of the elastic region EA. As shown in FIG. 5, in the case of the corrugated cardboard material, the stress takes on a constant value 1 in the plastic region PA. This means that in the elastic region EA, all the plurality of layers of corrugated cardboard sheets 51A constituting the corrugated cardboard material have the same strengths, and therefore they are crushed almost simultaneously at the time point of reaching the maximum stress. The corrugated cardboard sheet 51A absorbs impact force in the process of being crushed. Therefore, in the plastic region PA, there is almost no cushioning capacity (impact absorbing capacity). As seen from the graph shown in FIG. 5, the corrugated cardboard material that is the material of the first cushioning portion 51 is large in the maximum stress 1 and thus it is high in creep characteristics, but is extremely low in cushioning capacity in the plastic region PA.

[0054] As shown in FIG. 6, the foamed resin material elastically deforms to maximum stress 2. That is, in the elastic region EA until reaching the maximum stress 2, the change rate of the stress with respect to the strain is a constant value. In the plastic region PA after reaching the maximum stress 2, the change rate of the stress with respect to the strain takes on a positive value. That is, unlike the corrugated cardboard material, the foamed resin material has a cushioning capacity (impact absorbing capacity) by plastically deforming (viscoelastically deforming) in the plastic region PA. The foamed resin material that is the material of the second cushioning portion 52 is small in the maximum stress 2, but has a cushioning capacity even in the plastic region PA. Since the maximum stress 2 is small, the foamed resin material is low in creep characteristics. Therefore, when the foamed resin material is used alone, it is necessary to increase the area of the surface on the cushioning portion 50 side facing the electronic device 100. In this case, since a large area is required for the surface facing the electronic device 100, there is a case where of not being able to handle depending on the shape and size of the electronic device 100.

[0055] As shown in FIG. 7, the composite cushioning portion 53 elastically deforms to maximum stress 3. That is, in the elastic region EA, the change rate of the stress with respect to the strain takes on a relatively large constant value. This maximum stress 3 is larger than the maximum stress 2 of the foamed resin material shown in FIG. 6. By arranging the first cushioning portion 51 and the second cushioning portion 52 in parallel, the maximum stress 3 that is large can be obtained. This large maximum stress 3 is caused by the corrugated cardboard material. On the other hand, in the plastic region PA after reaching the maximum stress 3, the change rate of the stress with respect to the strain takes on a positive value. By arranging the first cushioning portion 51 and the second cushioning portion 52 in parallel, the composite cushioning portion 53 plastically deforms in the plastic region PA. This plastic deformation is viscoelastic deformation. This plastic deformation is caused by the foamed resin material. Thus, the composite cushioning portion 53 has high creep characteristics due to the large maximum stress 3 and plastically deforms in the plastic region PA, and therefore has high cushioning capacity (impact absorbing capacity).

[0056] As seen from FIGS. 5 to 7, the composite cushioning portion 53 in which the first cushioning portion 51 and the second cushioning portion 52 are arranged in parallel has a larger maximum stress 3 than that in the case of the foamed resin material alone. Moreover, the change rate (slope) of the stress with respect to the strain takes on a positive value in the plastic region PA. As seen from the stress-strain diagrams shown in FIGS. 5 to 7, the first cushioning portion 51, the second cushioning portion 52, and the composite cushioning portion 53 have relationships presented in the following (a) to (c). In the present embodiment, the composite cushioning portion 53 satisfying this relationship is adopted. [0057] (a) The maximum stress 1 in the elastic region EA of the first cushioning portion 51 is larger than the maximum stress 2 in the elastic region EA of the second cushioning portion 52. [0058] (b) The slope indicating the ratio of the stress with respect to the strain in the plastic region PA of the first cushioning portion 51 takes on a value of zero or close to zero, and the slope indicating the ratio of the stress with respect to the strain in the plastic region PA of the second cushioning portion 52 takes on a positive value larger than the value of the slope of the first cushioning portion 51. [0059] (c) The maximum stress 3 in the elastic region EA of the composite cushioning portion 51 configured by arranging the first cushioning portion 53 and the second cushioning portion 52 in parallel in the direction facing the electronic device 100 is larger than the maximum stress 2 of the second cushioning portion 52, and the slope in the plastic region PA of the composite cushioning portion 53 takes on a positive value larger than the value of the slope of the first cushioning portion 51.

[0060] By satisfying the relationship presented in the (a) to (c) described above, the cushioning portion 50 having excellent cushioning characteristics can be obtained.

Relationship Between Acceleration and Time at Time of Impact Application

[0061] Next, the relationship between the acceleration of the external force applied to the electronic device 100 via the cushioning portion at the time of impact application and time will be described with reference to FIGS. 8 to 10. In the graphs shown in FIGS. 8 to 10, the vertical axes represent acceleration G of the external force applied to the electronic device 100, and the horizontal axes represent time t. The time t is an elapsed time from when the electronic device 100 starts to be applied with the external force. The relationship between the acceleration G of the external force applied to the electronic device 100 and the time t when the electronic device 100 is dropped from a predetermined height in a state where the cushioning portion is interposed between the electronic device 100 and a floor surface is shown. When dropping onto the floor surface, the electronic device 100 receives a compressive force as an external force from the cushioning portion. Therefore, in the electronic device 100, acceleration according to the compressive force is generated. The cushioning portion is the first cushioning portion 51, the second cushioning portion 52, and the composite cushioning portion 53.

[0062] FIG. 8 shows the relationship between the acceleration G of the external force applied to the electronic device 100 at the time of dropping and the time t when the cushioning portion is the corrugated cardboard material constituting the first cushioning portion 51. FIG. 9 shows the relationship between the acceleration G of the external force applied to the electronic device 100 at the time of dropping and the time t when the cushioning portion is the foamed resin material constituting the second cushioning portion 52. FIG. 10 shows the relationship between the acceleration G of the external force applied to the electronic device 100 at the time of dropping and the time t when the cushioning portion is the composite cushioning portion 53. Each graph also shows the relationship between the external force applied to the electronic device 100 at the time of impact application and time. The external force applied to the electronic device 100 at the time of impact application depends on the mass of the electronic device 100. When the mass of the electronic device 100 is the same, the waveform of each graph also indicates the relationship between the external force applied to the electronic device 100 and time. Note that FIG. 8 assumes that the following state occurs when electronic device 100 is dropped from a predetermined height in a state where first cushioning portion 51 is interposed between electronic device 100 and the floor surface. That is, it is assumed that the electronic device 100 stops before all of the plurality of corrugated cardboard sheets 51A constituting the first cushioning portion 51 are compressed and crushed.

[0063] As shown in FIGS. 8 and 9, the types of waveforms of the graphs of the first cushioning portion 51 and the second cushioning portion 52 are different. The waveform of the graph of the first cushioning portion 51 is a trapezoidal wave. The waveform of the graph of the second cushioning portion 52 is a half-sine wave. That is, the first cushioning portion 51 includes a material whose waveform is a trapezoidal wave. The second cushioning portion 52 includes a material whose waveform is a half-sine wave. In the present embodiment, the first cushioning portion 51 includes a corrugated cardboard material as a material whose waveform is a trapezoidal wave. The second cushioning portion 52 includes a foamed resin material as a material whose waveform is a half-sine wave. The waveform of the corrugated cardboard material becomes a trapezoidal wave because the change rate of the stress with respect to the strain is substantially 0 (zero) in the plastic region PA in the stress-strain diagram shown in FIG. 5. The waveform of the foamed resin material becomes a half-sine wave because the change rate of the stress with respect to the strain takes on a positive value in the plastic region PA in the stress-strain diagram shown in FIG. 6.

[0064] The trapezoidal wave that is the waveform of the graph of the corrugated cardboard material is a composite wave in which a plurality of half-sine waves having different frequencies are superimposed. When this trapezoidal wave includes the same frequency as the natural frequency of the electronic device 100, the electronic device 100 resonates. In this case, the electronic device 100 is applied with a large impact. The natural vibration of the electronic device 100 varies depending on the type of the electronic device 100 to be packaged. Therefore, in order to provide the cushioning material 40 having versatility, it is required not to resonate any type of electronic device 100.

[0065] The graph of the composite cushioning portion 53 shown in FIG. 10 includes a half-sine wave. No trapezoidal wave is included. For this reason, the electronic device 100 is less likely to resonate when dropping onto the floor surface via the cushioning portion 50 (composite cushioning portion 53).

[0066] A corrugated cardboard material made of paper is vulnerable to humidity. Paper decreases its strength when it absorbs moisture. That is, in the stress-strain diagram shown in FIG. 5, the maximum stress 1 of the corrugated cardboard material that has absorbed moisture decreases. Even when the strength of the corrugated cardboard material decreases due to the influence of humidity, in order to ensure a necessary cushioning force, the thickness of the corrugated cardboard material is made thicker than a value required at the time of drying. This leads to an increase in the thickness of the cushioning portion 50 and consequently an increase in the size of the packaged item 10.

[0067] On the other hand, the cushioning portion 50 of the present embodiment is partially occupied by a water-resistant foamed resin material. Therefore, it is possible to thin the first cushioning portion 51 made of a corrugated cardboard material according to the proportion occupied by the foamed resin material in the composite cushioning portion 53. Therefore, even if the thickness of the thinned corrugated cardboard is added with the thickness of the corrugated cardboard by a proportion in consideration of the influence of humidity, it is possible to thin the thickness of the first cushioning portion 51 constituting the composite cushioning portion 53 as compared with the case where the cushioning portion 50 is constituted by the corrugated cardboard alone. Therefore, it is possible to thin the cushioning portion 50 including the composite cushioning portion 53.

Actions of Embodiment

[0068] Next, actions of the packaged item 10, the packaging material 20, and the cushioning material 40 will be described. In the present embodiment, the cushioning portion 50 is configured by arranging, in parallel, the first cushioning portion 51 and the second cushioning portion 52 made of different cushioning materials with respect to the compression direction. This can control the cushioning characteristics by the area ratio between the first cushioning portion 51 and the second cushioning portion 52. The cushioning portion 50 includes the composite cushioning portion 53 configured by arranging, in parallel, the first cushioning portion 51 and the second cushioning portion 52 with respect to the compression direction. The maximum stress 3 of the composite cushioning portion 53 is increased by increasing the area ratio of the first cushioning portion 51 made of the corrugated cardboard material. The positive slope indicating the change rate of the stress with respect to the strain in the plastic region PA of the composite cushioning portion 53 is increased by increasing the area ratio of the second cushioning portion 52 made of the foamed resin material.

[0069] As shown in FIG. 7, the cushioning portion 50 including the composite cushioning portion 53 has the maximum stress 3 sufficiently larger than the maximum stress 2 of the foamed resin material alone. That is, the cushioning portion 50 has the maximum stress 3 that is high closer to the maximum stress 1 of the corrugated cardboard material than the maximum stress 2 of the foamed resin material. This can improve the creep characteristics of the cushioning portion 50. For example, in the case of a configuration with the foamed resin material alone, the maximum stress 2 is so small that the creep characteristics are low. In this case, it is necessary to increase the area of the foamed resin material. On the other hand, the cushioning portion 50 can obtain the maximum stress 3 higher than that of the foamed resin material alone. This contributes to downsizing (area reduction) of the cushioning portion 50.

[0070] As shown in FIG. 7, the cushioning portion 50 including the composite cushioning portion 53 takes on a positive value in the slope indicating the change rate of the stress with respect to the strain . Therefore, the waveform (impact waveform) of the acceleration of the external force applied to the electronic device 100 at the time of drop impact becomes a half-sine wave shown in FIG. 10. That is, the impact waveform includes no trapezoidal wave (FIG. 8). Therefore, when the packaged item 10 drops, the electronic device 100 in contact with the cushioning portion 50 including the composite cushioning portion 53 is less likely to resonate.

[0071] When the cushioning portion 50 is made of the corrugated cardboard material alone, cushioning characteristics due to the influence of humidity are likely to deteriorate. Therefore, it is necessary to increase the thickness of the cushioning portion 50 in consideration of the influence of humidity. That is, even if the cushioning characteristics deteriorate due to the influence of humidity, it is necessary to thicken the corrugated cardboard material so that necessary cushioning characteristics can be obtained. This leads to an increase in size of the packaged item 10.

[0072] On the other hand, the cushioning portion 50 of the present embodiment includes the composite cushioning portion 53, which is an assembly of the corrugated cardboard material and the foamed resin material. Therefore, the proportion of increasing the thickness due to the influence of humidity can be a value corresponding to the area ratio occupied by the corrugated cardboard material. Therefore, it is possible to suppress a value of increasing the thickness of the corrugated cardboard material constituting the composite cushioning portion 53 in consideration of the influence of humidity. Therefore, it is possible to thin the cushioning portion 50. As a result, the size of the packaged item 10 can be reduced as compared with the case where the impact absorbing portion is formed of the foamed resin material alone.

Effects of Embodiment

[0073] Therefore, according to this embodiment, the following effects can be obtained.

[0074] (1) The cushioning material 40 cushions the external force applied to the electronic device 100. The cushioning material 40 includes the support plate 42 and the cushioning portion 50. The support plate 42 is a member configured to support the electronic device 100. The cushioning portion 50 is included in the support plate 42 and cushions the external force applied to the electronic device 100. The cushioning portion 50 includes the first cushioning portion 51 and the second cushioning portion 52. The first cushioning portion 51 includes the first surface 61 fixed to the support plate 42 and the second surface 62 facing the electronic device 100. The second cushioning portion 52 has the third surface 63 fixed to the support plate 42 and the fourth surface 64 facing the electronic device 100. In the graph where the vertical axis represents the external force applied to the electronic device 100 and the horizontal axis represents the time since the electronic device 100 starts to be applied with the external force, the types of waveforms of the graphs of the first cushioning portion 51 and the second cushioning portion 52 are different. According to this configuration, the cushioning material 40 having high versatility can be provided by arranging, side by side, the first cushioning portion 51 and the second cushioning portion 52 having different types of waveforms. For example, since the area ratio can be easily varied, fine adjustment of the cushioning characteristics is easy. Furthermore, it is easy to reduce the thicknesses of the cushioning portions 51 and 52. Therefore, it is possible to provide the cushioning material 40 that has high versatility and can be thinned. Therefore, the packaging material 20 can be downsized without deteriorating the cushioning performance. As a result, it is possible to reduce the transportation cost and the cost of the packaging material 20.

[0075] (2) The first cushioning portion 51 and the second cushioning portion 52 are arranged in contact with each other. According to this configuration, it is possible to reduce an occurrence of a state in which only any one of the first cushioning portion 51 and the second cushioning portion 52 is applied with a force.

[0076] (3) Any one of the first cushioning portion 51 and the second cushioning portion 52 is arranged with the periphery surrounded by the other. According to this configuration, it is possible to suppress generation of a gap between the first cushioning portion 51 and the second cushioning portion 52 due to an external force.

[0077] (4) The second surface 62 and the fourth surface 64 are flush with each other. According to this configuration, it is possible to reduce an occurrence of a state in which only any one of the first cushioning portion 51 and the second cushioning portion 52 is applied with a force. (5) The first cushioning portion 51 includes a material whose waveform is a trapezoidal wave, and the second cushioning portion 52 includes a material whose waveform is a half-sine wave. According to this configuration, it is possible to provide the cushioning material 40 having both the creep characteristics and the cushioning characteristics by compensating for the respective weaknesses of the creep characteristics and the cushioning characteristics.

[0078] (6) The material of the first cushioning portion 51 is a corrugated cardboard material, and the second cushioning portion 52 is a foamed resin material. According to this configuration, since two types of materials easily available from the viewpoints of price and mass production are used, it is easy to mass-produce the cushioning material 40 having high versatility at a low price.

[0079] (7) The cushioning material 40 includes the support plate 42 and the cushioning portion 50. The support plate 42 is a member configured to support the electronic device 100. The cushioning portion 50 is included in the support plate 42 and cushions the external force applied to the electronic device 100. The cushioning portion 50 includes the first cushioning portion 51 and the second cushioning portion 52. The first cushioning portion 51 includes the first surface 61 fixed to the support plate 42 and the second surface 62 facing the electronic device 100. The second cushioning portion 52 has the third surface 63 fixed to the support plate 42 and the fourth surface 64 facing the electronic device 100. The following (a) to (c) are satisfied in the graph of the stress-strain diagram in which the vertical axis represents the compressive stress applied to the cushioning portion and the horizontal axis represents the strain applied to the cushioning portion. [0080] (a) The maximum stress 1 in the elastic region EA of the first cushioning portion 51 is larger than the maximum stress 2 in the elastic region EA of the second cushioning portion 52. [0081] (b) The slope indicating the ratio of the stress with respect to the strain in the plastic region PA of the first cushioning portion 51 takes on a value of zero or close to zero, and the slope indicating the ratio of the stress with respect to the strain in the plastic region PA of the second cushioning portion 52 takes on a positive value larger than the value of the slope of the first cushioning portion 51. [0082] (c) The maximum stress 3 in the elastic region EA of the composite cushioning portion 51 configured by arranging the first cushioning portion 53 and the second cushioning portion 52 in parallel in the direction facing the electronic device 100 is larger than the maximum stress 2 of the second cushioning portion 52, and the slope in the plastic region PA of the composite cushioning portion 53 takes on a positive value larger than the value of the slope of the first cushioning portion 51.

[0083] According to this configuration, by arranging, in parallel, the first cushioning portion 51 and the second cushioning portion 52 respectively including different materials excellent in respective one of the maximum stress and the slope of the plastic region PA, it is possible to provide the packaging material 20 having high versatility. Since the area ratio can be easily varied, fine adjustment of the cushioning characteristics is easy.

[0084] (8) The first cushioning portion 51 is made of a corrugated cardboard material, and the second cushioning portion 52 is made of a foamed resin material. According to this configuration, by combining the cushioning material 40 easily available from the viewpoints of price and mass production, it is possible to provide the packaging material 20 having high versatility and high cushioning effect. When the corrugated cardboard material is made of paper, it is possible to provide the cushioning material 40 resistant to moisture (humidity) according to the proportion occupied by the foamed resin material.

[0085] (9) The electronic device 100 is the recording device 110. According to this configuration, the recording device 110 can be protected from impact.

[0086] (10) The packaging material 20 includes the packaging box 30 configured to accommodate the electronic device 100, and the cushioning material 40. According to this configuration, the electronic device 100 stored in the packaging box 30 can be effectively protected from impact by the cushioning material 40.

[0087] (11) The packaged item 10 includes the packaging material 20 and the electronic device 100. According to this configuration, the electronic device 100 in the packaged item 10 can be protected from impact.

Modifications

[0088] The embodiment described above can be changed to a form as a modifications described below. Furthermore, further modifications can be made by appropriately combining the embodiment described above and modifications given below, and further modifications can be made by appropriately combining the modifications given below.

[0089] Any one of the first cushioning portion 51 and the second cushioning portion 52 may be arranged with the periphery surrounded by the other. The relationship between one and the other may be opposite to that in the embodiment described above. For example, as illustrated in FIGS. 11 and 12, the second cushioning portion 52 that is one may be arranged with the periphery surrounded by the first cushioning portion 51 that is the other. According to this configuration, it is easy to avoid the electronic device 100 from coming into contact with the second cushioning portion 52 before the first cushioning portion 51, as compared with the embodiment described above.

[0090] The second cushioning portion 52 made of the foamed resin material in the embodiment described above may be changed to the second cushioning portion 54 made of the corrugated cardboard material illustrated in FIGS. 13 and 14. As illustrated in FIGS. 13 and 14, both the first cushioning portion 51 and the second cushioning portion 54 may be made of the same material, that is, a corrugated cardboard material. That is, a composite cushioning portion 55 may be configured by arranging, in parallel, the first cushioning portion 51 made of the corrugated cardboard material and the second cushioning portion 54 made of the corrugated cardboard material with respect to a direction facing the electronic device 100. The cushioning portion 50 may be configured by the composite cushioning portion 55. Even if both are made of a corrugated cardboard material, the types of waveforms of the graphs indicating the relationship between the acceleration G of the external force applied to the electronic device 100 from each of the first cushioning portion 51 and the second cushioning portion 54 at the time of impact application and the time t may be different. Specifically, the waveform of the graph indicating the relationship between the acceleration G of the external force applied to the electronic device 100 via the first cushioning portion 51 and the time t may be a trapezoidal wave. The waveform of the graph indicating the relationship between the acceleration G of the external force applied to the electronic device 100 via the second cushioning portion 54 and the time t may be a half-sine wave. That is, the first cushioning portion 51 includes a material whose waveform is a trapezoidal wave, and the second cushioning portion 54 includes a material whose waveform is a half-sine wave. The first cushioning portion 51, the second cushioning portion 54, and the composite cushioning portion 55 may satisfy the conditions (a) to (c) described above in the embodiment described above in a stress-strain diagram illustrating a relationship between each compressive stress and the strain . The first cushioning portion 51 and the second cushioning portion 54 may be arranged in contact with each other. Furthermore, any one of the first cushioning portion 51 and the second cushioning portion 54 may be arranged with the periphery surrounded by the other. In the example illustrated in FIG. 13, the first cushioning portion 51 that is one is arranged with the periphery surrounded by the second cushioning portion 54 that is the other. The second surface 62 and the fourth surface 64 may be flush with each other. As illustrated in FIG. 14, the corrugated cardboard material constituting the first cushioning portion 51 has the same structure as that of the embodiment described above. That is, the corrugated cardboard material has a structure in which the plurality of corrugated cardboard sheets 51A having the same layer structures are laminated. That is, the material of the first cushioning portion 51 is a corrugated cardboard material formed by laminating the plurality of corrugated cardboard sheets 51A having the same layer structures with the same hardness (compressive strengths). Therefore, the waveform of the first cushioning portion 51 is a trapezoidal wave. On the other hand, the corrugated cardboard material that is the material of the second cushioning portion 54 has a structure in which a plurality of corrugated cardboard sheets 54A having different hardness (compressive strengths) are laminated. In particular, the corrugated cardboard material that is the material of the second cushioning portion 54 includes the plurality of layers of corrugated cardboard sheets 54A whose hardness changes stepwise from a soft layer to a hard layer. The plurality of layers of corrugated cardboard sheets 54A each have a different thickness of a layer that is one element for determining hardness. On the other hand, the waveform of the second cushioning portion 54 made of a corrugated cardboard material formed by laminating the plurality of layers of corrugated cardboard sheets 54A whose hardness changes stepwise is a half-sine wave. This is because the plurality of layers of corrugated cardboard sheets 54A having different hardness are arranged in series in a direction facing the electronic device 100. The individual waveforms of the respective layers of the corrugated cardboard sheets 54A are trapezoidal waves having different heights. By combining these trapezoidal waves having different heights, a pseudo half-sine wave close to the half-sine wave shown in FIG. 10 is formed.

[0091] In the embodiment described above, as illustrated in FIG. 3, the outer shape of the first cushioning portion 51 and the outer shape of the second cushioning portion 52 are a combination of the same shapes of quadrangles, but may be a combination of different shapes. That is, the outer shape of the first cushioning portion 51 (i.e., the inner shape of the second cushioning portion 52) and the outer shape of the second cushioning portion 52 may be a combination of different shapes. For example, a combination in which the outer shape of the first cushioning portion 51 is circular and the outer shape of the second cushioning portion 52 is rectangular may be used. Conversely, a combination in which the outer shape of the first cushioning portion 51 is rectangular and the outer shape of the second cushioning portion 52 is circular may be used. The shapes to be combined may be combinations of other different shapes among a circle, a triangle, a quadrangle, a pentagon, a hexagon, an ellipse, a rhombus, and the like.

[0092] In the embodiment described above, the second cushioning portion 52 surrounding the periphery of the first cushioning portion 51 includes one member, but may include a plurality of members. That is, the second cushioning portion 52 may include a plurality of members arranged so as to surround the first cushioning portion 51.

[0093] Any one of the first cushioning portion 51 and the second cushioning portions 52 and 54 needs not be arranged with the periphery surrounded by the other. For example, the first cushioning portion 51 and the second cushioning portions 52 and 54 may both have quadrangular plate shapes, and may be arranged so as to be in contact with only one side surface.

[0094] The second surface 62 and the fourth surface 64 need not be flush with each other. For example, the thickness of the second cushioning portions 52 and 54 may be larger than the thickness of the first cushioning portion 51, or conversely, the thickness of the first cushioning portion 51 may be larger than the thickness of the second cushioning portions 52 and 54.

[0095] The first cushioning portion 51 and the second cushioning portions 52 and 54 need not be arranged in contact with each other. For example, the first cushioning portion 51 and the second cushioning portions 52 and 54 may be arranged at positions away from each other in parallel with respect to the direction facing the electronic device 100. In short, the position where the first cushioning portion 51 and the second cushioning portion 52 are arranged on the fixed surface 42P of the support plate 42 may be any position as long as the second surface 62 and the fourth surface 64 can face one surface of the outer peripheral surfaces of the electronic device 100.

[0096] The number of support plates 42 included in support portion 41 is not limited to four, and may be changed to another number. For example, the number of the support plates 42 may be one, two, or three. For example, in a case of two, the two support plates 42 are arranged orthogonal to each other. In a case of three, the three support plates 42 are arranged orthogonal to one another. Furthermore, the number of the support plates 42 may be five or six. In a case of five or six, the packaging box 30 may also serve as the support plate 42. The cushioning portion 50 may be directly fixed to the inner surface of the packaging box 30. In the case of five, the five surface portions of the packaging box 30 other than the flap 32 are used as the support plates 42, and the cushioning portion 50 is fixed to the inner surfaces of the five surface portions (the support plates 42).

[0097] The second surface 62 and the fourth surface 64 being flush with each other are not limited to a difference in height in the Z1 direction between the respective surfaces being 0 mm. For example, even if the position in the Z1 direction is shifted in a range where the timing at which the electronic device 100 come into contact with the second surface 62 and the fourth surface 64 can be regarded as substantially the same, the positions fall into being flush. In this case, if the second surface 62 and the fourth surface 64 are shifted by a length within a range of 5% or less of the thickness (Z1 direction dimension) of the cushioning portion 50, they may be regarded as being flush. Note that the thickness of the cushioning portion 50 depends on the size, shape, and weight of the electronic device 100, but is normally used in the range of 1 to 20 mm in many cases. In this example, if the dimensional difference in the Z1 direction between the second surface 62 and the fourth surface 64 is a value within a range of 0.05 mm to 1 mm, they may be regarded as being flush.

[0098] The second surface 62 and the fourth surface 64 need not be flush with each other. It is sufficient that a certain cushioning effect is obtained although the cushioning effect is lower than that in the case of being flush. When there is a step on the opposing surface on the electronic device 100 side, according to the two surfaces having the step, the second surface 62 and the fourth surface 64 may be provided with a difference in height according to the step. Furthermore, the second surface 62 of the first cushioning portion 51 may be made higher than the fourth surface 64 of the second cushioning portion 52 in order to enhance creep characteristics. The fourth surface 64 of the second cushioning portion 52 may be made higher than the second surface 62 of the first cushioning portion 51 in order to enhance the cushioning characteristics.

[0099] The number of cushioning portions 50 (composite cushioning portions 53) fixed to one support plate 42 may be appropriately changed. The number of the cushioning portions 50 per support plate may be one, two, three, four, or more. In a case of the support portion 41 having the plurality of support plates 42, the number of the cushioning portions 50 may be set for each of the support plates 42. The number of the cushioning portions 50 may be the same in all the support plates 42, or the number of the cushioning portions 50 may be set according to the area of the fixed surface 42P of the support plate 42.

[0100] In the embodiment described above and each modification of FIGS. 11, 13 and the like, the corrugated cardboard may be made of a synthetic resin in place of paper. In this case, in the modifications illustrated in FIGS. 13 and 14, the corrugated cardboard of one of the first cushioning portion 51 and the second cushioning portion 52 may be made of paper, and the corrugated cardboard of the other may be made of a synthetic resin.

[0101] The number of the cushioning portions 50 included in the support portion 41 is not limited to a plural and may be one. When the support portion 41 has the plurality of support plates 42, the cushioning portion 50 including the composite cushioning portion 53 may be fixed to only one support plate 42 of the plurality of support plates 42. In this case, a cushioning portion made of a cushioning material other than the composite cushioning portion 53 may be fixed to the other support plates 42.

Supplementary Notes

[0102] Hereinafter, technical spirits ascertained from the embodiment described above and the modifications will be described together with the effects.

[0103] (A) A cushioning material is a cushioning material configured to cushion an external force applied to an electronic device, the cushioning material including a support plate configured to support the electronic device, and a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device, the cushioning portion including a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device, and a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein in a graph in which a vertical axis represents an external force applied to the electronic device and a horizontal axis represents time from when the external force starts to be applied to the electronic device, types of waveforms of the graph are different between the first cushioning portion and the second cushioning portion.

[0104] According to this configuration, the cushioning material having high versatility can be provided by arranging, side by side, the first cushioning portion and the second cushioning portion having different types of waveforms. For example, since the area ratio can be easily varied, fine adjustment of the cushioning characteristics is easy. Furthermore, since it is easy to reduce the thickness of the cushioning portion, it is possible to thin the cushioning material. Therefore, it is possible to provide the cushioning material that has high versatility and can be thinned. Therefore, the packaging material can be downsized without deteriorating the cushioning performance. As a result, it is possible to reduce the transportation cost and the cost of the packaging material.

[0105] (B) A cushioning material is a cushioning material configured to cushion an external force applied to an electronic device, the cushioning material including a support plate configured to support the electronic device, and a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device, the cushioning portion including a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device, and a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein in a stress-strain diagram where a vertical axis represents compressive stress applied to the cushioning portion and a horizontal axis represents strain applied to the cushioning portion, (a) maximum stress in an elastic region of the first cushioning portion is larger than maximum stress in an elastic region of the second cushioning portion, (b) a slope indicating a ratio of stress with respect to strain in a plastic region of the first cushioning portion takes a value of zero or close to zero, and a slope indicating a ratio of stress with respect to strain in a plastic region of the second cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion, and (c) maximum stress in an elastic region of a composite cushioning portion configured by arranging the first cushioning portion and the second cushioning portion in parallel in a direction facing the electronic device is larger than the maximum stress of the second cushioning portion, and the slope in the plastic region of the composite cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion.

[0106] According to this configuration, by arranging, in parallel, the first cushioning portion and the second cushioning portion respectively including different materials excellent in respective one of the maximum stress and the slope of the plastic region, it is possible to provide the packaging material having high versatility. Since the area ratio can be easily varied, fine adjustment of the cushioning characteristics is easy. Furthermore, since it is easy to reduce the thickness of the cushioning portion, it is possible to thin the cushioning material. Therefore, it is possible to provide the cushioning material that has high versatility and can be thinned.

[0107] (C) In the cushioning material according to (A) or (B) described above, the first cushioning portion and the second cushioning portion may be arranged in contact with each other. According to this configuration, it is possible to reduce an occurrence of a state in which only any one of the first cushioning portion and the second cushioning portion is applied with a force.

[0108] (D) In the cushioning material according to any one of (A) to (C) described above, any one of the first cushioning portion and the second cushioning portion may be arranged with the periphery surrounded by the other. According to this configuration, it is possible to suppress generation of a gap between the first cushioning portion and the second cushioning portion due to an external force.

[0109] (E) In the cushioning material according to any one of (A) to (D) described above, the second surface and the fourth surface may be flush with each other. According to this configuration, it is possible to reduce an occurrence of a state in which only any one of the first cushioning portion and the second cushioning portion is applied with a force.

[0110] (F) In the cushioning material according to any one of (A) to (E) described above, the first cushioning portion may include a material whose waveform is a trapezoidal wave, and the second cushioning portion may include a material whose waveform is a half-sine wave. According to this configuration, it is possible to provide the cushioning material having both the creep characteristics and the cushioning characteristics by compensating for the respective weaknesses of the creep characteristics and the cushioning characteristics.

[0111] (G) In the cushioning material according to any one of (A) to (F) described above, the material of the first cushioning portion may be a corrugated cardboard material, and the second cushioning portion may be a foamed resin material. According to this configuration, since two types of materials easily available from the viewpoints of price and mass production are used, it is possible to provide a cushioning material having high versatility and high cushioning effect. When the corrugated cardboard material is made of paper, it is possible to provide the cushioning material resistant to moisture (humidity) according to the proportion occupied by the foamed resin material.

[0112] (H) In the cushioning material according to any one of (A) to (F) described above, the electronic device may be a recording device. According to this configuration, the recording device can be protected from impact.

[0113] (I) A packaging material includes a packaging box configured to accommodate the electronic device, and the cushioning material according to any one of (A) to (H) described above. According to this configuration, the electronic device stored in the packaging box can be effectively protected from impact by the cushioning material.

[0114] (J) A packaged item includes the packaging material according to (H) described above and the electronic device. According to this configuration, the electronic device in the packaged item can be protected from impact.