Patent Publication Number: US-2021188529-A1

Title: Packing device for printer, packing device for sheet transportation apparatus, printer including packing device, sheet transportation apparatus including packing device, method for manufacturing printer packed on packing device, and method for manufacturing sheet transportation apparatus packed on packing device

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-231965, filed Dec. 23, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     Embodiments of the present disclosure relate to a packing device for a printer, a packing device for a sheet transportation apparatus, a printer including a packing device, a sheet transportation apparatus including a packing device, a method for manufacturing a printer packed on a packing device, and a method for manufacturing a sheet transportation apparatus packed on a packing device. 
     2. Related Art 
     Cushioning corner blocks disclosed in JP-A-2000-302170 are formed using a foamed biodegradable plastic material and are put together by fitting a mating protrusion of one block into a mating hole of another block. 
     However, in the technique disclosed in JP-A-2000-302170, a pushing force applied for mating of two blocks and a pulling force applied for pulling one of the two blocks out of the other after the mating are not considered. Therefore, there is a possibility of insufficient mating strength, and the mating strength cannot be adjusted in some cases. 
     SUMMARY 
     A certain aspect is a packing device for a printer, the packing device comprising: a first packing portion that has a mating portion; and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion; wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate. 
     A certain aspect is a packing device for a sheet transportation apparatus, the packing device comprising: a first packing portion that has a mating portion; and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion; wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate. 
     A certain aspect is a printer including a packing device, the packing device comprising: a first packing portion that has a mating portion; and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion; wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate, one of the first packing portion and the second packing portion accommodates an installation portion and a first wall portion of the printer, and the other of the first packing portion and the second packing portion faces a second wall portion of the printer and mates with the one of the first packing portion and the second packing portion. 
     A certain aspect is a sheet transportation apparatus including a packing device, the packing device comprising: a first packing portion that has a mating portion; and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion; wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate, one of the first packing portion and the second packing portion accommodates an installation portion and a first wall portion of the sheet transportation apparatus, and the other of the first packing portion and the second packing portion faces a second wall portion of the sheet transportation apparatus and mates with the one of the first packing portion and the second packing portion. 
     A certain aspect is a method for manufacturing a printer packed on a packing device, the packing device including a first packing portion that has a mating portion, and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion, wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate, the method comprising: accommodating an installation portion and a first wall portion of the printer by one of the first packing portion and the second packing portion; and putting the other of the first packing portion and the second packing portion to face a second wall portion of the printer and mate with the one of the first packing portion and the second packing portion. 
     A certain aspect is a method for manufacturing a sheet transportation apparatus packed on a packing device, the packing device including a first packing portion that has a mating portion, and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion, wherein at least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate, the method comprising: accommodating an installation portion and a first wall portion of the sheet transportation apparatus by one of the first packing portion and the second packing portion; and putting the other of the first packing portion and the second packing portion to face a second wall portion of the sheet transportation apparatus and mate with the one of the first packing portion and the second packing portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external perspective view illustrating the schematic structure of a first packing device according to an exemplary embodiment. 
         FIG. 2  is an external perspective view illustrating the schematic structure of a first packing device according to an exemplary embodiment. 
         FIG. 3  is a side view illustrating the schematic structure of a first packing device according to an exemplary embodiment. 
         FIG. 4  is an external perspective view illustrating the schematic structure of a 1st-2 packing portion of a packing device according to a variation example. 
         FIG. 5  is an external perspective view illustrating the schematic structure of a 1st-3 packing portion of a packing device according to a variation example. 
         FIG. 6  is an external perspective view illustrating the schematic structure of a 1st-4 packing portion of a packing device according to a variation example. 
         FIG. 7  is an external perspective view illustrating the schematic structure of a first mating portion of a 1st-4 packing portion of a packing device according to a variation example. 
         FIG. 8  is a diagram for explaining a relationship between forces regarding mating in a second packing device according to an exemplary embodiment. 
         FIG. 9  is a diagram for explaining a relationship between forces regarding mating in a second packing device according to an exemplary embodiment. 
         FIG. 10  is a side view illustrating the schematic structure of a 1st-5 packing portion of a packing device according to a variation example. 
         FIG. 11  is a side view illustrating the schematic structure of a third packing device according to a variation example. 
         FIG. 12  is a side view illustrating the schematic structure of a fourth packing device according to a variation example. 
         FIG. 13  is a side view illustrating the schematic structure of a fifth packing device according to a variation example. 
         FIG. 14  is a diagram for explaining a method for manufacturing a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 15  is a diagram for explaining a method for manufacturing a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 16  is a diagram for explaining a method for manufacturing a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 17  is a diagram illustrating an example of the appearance of a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 18  is a diagram illustrating an example of the appearance of a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 19  is a diagram illustrating an example of the appearance of a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 20  is a diagram illustrating an example of the appearance of a printer packed on a sixth packing device according to an exemplary embodiment. 
         FIG. 21  is a diagram for explaining a method for manufacturing a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 22  is a diagram for explaining a method for manufacturing a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 23  is a diagram for explaining a method for manufacturing a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 24  is a diagram illustrating an example of the appearance of a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 25  is a diagram illustrating an example of the appearance of a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 26  is a diagram illustrating an example of the appearance of a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
         FIG. 27  is a diagram illustrating an example of the appearance of a sheet transportation apparatus packed on a seventh packing device according to an exemplary embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Exemplary embodiments will now be explained with reference to the accompanying drawings. 
       FIG. 1  is an external perspective view illustrating the schematic structure of a first packing device  1  according to an exemplary embodiment.  FIG. 2  is another external perspective view illustrating the schematic structure of the first packing device  1  according to the exemplary embodiment. The direction of perspective view in  FIG. 2  is different from that of  FIG. 1 .  FIG. 3  is a side view illustrating the schematic structure of the first packing device  1  according to the exemplary embodiment. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 1 to 3 . In the example illustrated in  FIGS. 1 to 3 , to facilitate an explanation, an example of a packing device is referred to as the first packing device  1 . 
     The first packing device  1  may be used as, for example, a packing device for a printer, or as a packing device for a sheet transportation apparatus. A sheet transportation apparatus is annexed to a printer and has a function of transporting sheets of paper outputted from the printer, etc. 
     The first packing device  1  includes a first packing portion  11  and a second packing portion  12 . The first packing portion  11  includes a first mating base  31  and a mating portion. To facilitate an explanation, the base of the first packing portion  11  is referred to as the first mating base  31 . The first packing portion  11  includes a first mating portion  32  and a second mating portion  33  collectively as its mating portion. Each of the first mating portion  32  and the second mating portion  33  is a protrusion having a height in a direction parallel to the Z axis from the first mating base  31 . The protrusion protrudes in the negative direction along the Z axis. The protrusion may be referred to as, for example, a convex portion. The first mating base  31  supports the first mating portion  32  and the second mating portion  33 . 
     The second packing portion  12  includes a first mating receptacle base  51  and a mating receptacle portion. To facilitate an explanation, the base of the second packing portion  12  is referred to as the first mating receptacle base  51 . The second packing portion  12  includes a first mating receptacle portion  52  and a second mating receptacle portion  53  collectively as its mating receptacle portion. Each of the first mating receptacle portion  52  and the second mating receptacle portion  53  is a hole having a depth in the direction parallel to the Z axis in the first mating receptacle base  51 . The hole goes down in the negative direction along the Z axis. The hole may be referred to as, for example, a concave portion. The first mating receptacle base  51  is an example of a base. 
     In the present embodiment, each of the first packing portion  11  and the second packing portion  12  is made of a foamed plastic cushioning material. Various kinds of material can be used as the foamed plastic cushioning material. For example, polystyrene, urethane, polypropylene, or polyethylene, etc. may be used. The polystyrene used as such a material may be expanded polystyrene (EPS). As another example, either one of the first packing portion  11  and the second packing portion  12 , or both, may be made of an elastic material that has elasticity, for example, rubber. Either one of the first packing portion  11  and the second packing portion  12 , or both, may be made of two or more different kinds of material. These kinds of material may be, for example, various kinds of foamed plastic cushioning material or elastic material such as rubber. For example, the material used for forming the first packing portion  11  and the material used for forming the second packing portion  12  may be different from each other. These kinds of material may be, for example, various kinds of foamed plastic cushioning material or elastic material such as rubber. 
     The first mating receptacle portion  52  is able to mate with the first mating portion  32  by inserting at least a part of the first mating portion  32  into the first mating receptacle portion  52 . At least one of the first mating portion  32  and the first mating receptacle portion  52  has a sloped surface that is inclined with respect to a first axis extending in a direction in which the first mating portion  32  and the first mating receptacle portion  52  mate with each other. In the example illustrated in  FIGS. 1 to 3 , the first axis is the Z axis. As another example, the first axis may be defined as another axis that is parallel to the Z axis. 
     The protrusion of the first mating portion  32  and the hole of the first mating receptacle portion  52 , for example, may substantially match in shape or may have approximately the same size, for example. For example, one of the protruding shape of the first mating portion  32  and the recessed shape of the first mating receptacle portion  52  may be slightly smaller than the other. If each of the first mating portion  32  and the first mating receptacle portion  52  has a sloped surface that is inclined with respect to the first axis, for example, the angle of inclination of the sloped surface of the protrusion of the first mating portion  32  and the angle of inclination of the sloped surface of the hole of the first mating receptacle portion  52  may be slightly different from each other. Various other shapes can be adopted for the shape of them. 
     In the example illustrated in  FIGS. 1 to 3 , both the first mating portion  32  and the first mating receptacle portion  52  are inclined in their surfaces with respect to the first axis. The inclined surface has a shape that allows the first mating portion  32  and the first mating receptacle portion  52  to mate with each other. In the example illustrated in  FIGS. 1 to 3 , the inclined surface has a tapered shape. The tapered shape may be referred to as, for example, a wedge-like shape. Since the first mating portion  32  has a sloped surface that is inclined with respect to the first axis, the cross-sectional area size of a section parallel to the X-Y plane decreases as the distance from the first mating base  31  in the direction parallel to the first axis increases. In other words, the farther from the first mating base  31  in the direction parallel to the Z axis, the narrower the first mating portion  32 . Since the first mating receptacle portion  52  has a sloped surface that is inclined with respect to the first axis, the cross-sectional area size of a section parallel to the X-Y plane decreases as it goes deeper into the inside of the hole from the face of the first mating receptacle base  51  in the direction parallel to the first axis. In other words, the deeper into the inside of the hole from the face of the first mating receptacle base  51  in the direction parallel to the Z axis, the narrower the first mating receptacle portion  52 . In the present embodiment, the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, is taken as an example. Instead, for example, the cross-sectional area size of a section parallel to a plane intersecting with but not perpendicular to the first axis may be used. 
     The shape of the second mating portion  33  and the shape of the second mating receptacle portion  53  are the same as the shape of the first mating portion  32  and the shape of the first mating receptacle portion  52 , respectively. In the example illustrated in  FIGS. 1 to 3 , double mating, that is, the mating of the first mating portion  32  with the first mating receptacle portion  52  and the mating of the second mating portion  33  with the second mating receptacle portion  53 , offers greater total mating strength. The number of combination(s) of the mating portion and the mating receptacle portion is arbitrary, and may be one, two as in the example illustrated in  FIGS. 1 to 3 , or three or more. 
     The first packing device  1  has the following layout: when the surface of the first packing portion  11  on which the first mating portion  32  and the second mating portion  33  are provided and the surface of the second packing portion  12  in which the first mating receptacle portion  52  and the second mating receptacle portion  53  are provided are oriented in such a way as to face with each other and are then brought closer to each other in parallel with the Z-axis direction, the first mating portion  32  and the first mating receptacle portion  52  mate with each other, and the second mating portion  33  and the second mating receptacle portion  53  mate with each other. 
       FIG. 4  is an external perspective view illustrating the schematic structure of a modified first (referred to as “1st-2”; similar notation is used hereinafter) packing portion  111  of a packing device according to a variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 4 . The 1st-2 packing portion  111  includes a second mating base  131 , a 1st-2 mating portion  132 , a first portion  151  of the 1st-2 mating portion  132 , a 2nd-2 mating portion  133 , and a 1st-2 portion  152  of the 2nd-2 mating portion  133 . The structure of the 1st-2 packing portion  111  is, roughly speaking, the same as the structure of the first packing portion  11  illustrated in  FIGS. 1 to 3  except that the 1st-2 packing portion  111  has the first portion  151  and the 1st-2 portion  152 . However, the shape and size of each portion constituting its structure may be adjusted appropriately, as may be necessary for providing the first portion  151  and the 1st-2 portion  152 . The 1st-2 packing portion  111  is another example of a first packing portion. The second mating base  131  is an example of a base. Each of the 1st-2 mating portion  132  and the 2nd-2 mating portion  133  is an example of a mating portion. Each of the first portion  151  and the 1st-2 portion  152  is an example of a first portion. 
     The first portion  151  of the 1st-2 mating portion  132  is provided between the second mating base  131  and the 1st-2 mating portion  132 . That is, the 1st-2 packing portion  111  includes the second mating base  131 , which supports the mating portion, and the first portion  151  and the 1st-2 portion  152 , each of which is provided between the second mating base  131  and the mating portion. In the example illustrated in  FIG. 4 , the 1st-2 mating portion  132  and the 2nd-2 mating portion  133  serve as the mating portion. 
     Regarding the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, at the junction between the first portion  151  and the 1st-2 mating portion  132 , the cross-sectional area size of the first portion  151  is smaller than the cross-sectional area size of the 1st-2 mating portion  132 . Instead of the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, the cross-sectional area size of a section parallel to a plane intersecting with but not perpendicular to the first axis may be used. In this example, the first axis is parallel to the Z axis. The shape of the 2nd-2 mating portion  133  and the shape of its 1st-2 portion  152  are the same as the shape of the 1st-2 mating portion  132  and the shape of its first portion  151 , respectively. 
       FIG. 5  is an external perspective view illustrating the schematic structure of a 1st-3 packing portion  211  of a packing device according to another variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 5 . The 1st-3 packing portion  211  includes a third mating base  231 , a 1st-3 mating portion  232 , a second portion  251  of the 1st-3 mating portion  232 , a 2nd-3 mating portion  233 , and a 2nd-2 portion  252  of the 2nd-3 mating portion  233 . The structure of the 1st-3 packing portion  211  is, roughly speaking, the same as the structure of the first packing portion  11  illustrated in  FIGS. 1 to 3  except that the 1st-3 packing portion  211  has the second portion  251  and the 2nd-2 portion  252 . However, the shape and size of each portion constituting its structure may be adjusted appropriately, as may be necessary for providing the second portion  251  and the 2nd-2 portion  252 . The 1st-3 packing portion  211  is another example of a first packing portion. The third mating base  231  is an example of a base. Each of the 1st-3 mating portion  232  and the 2nd-3 mating portion  233  is an example of a mating portion. Each of the second portion  251  and the 2nd-2 portion  252  is an example of a second portion. 
     The second portion  251  of the 1st-3 mating portion  232  is provided between the third mating base  231  and the 1st-3 mating portion  232 . That is, the 1st-3 packing portion  211  includes the third mating base  231 , which supports the mating portion, and the second portion  251  and the 2nd-2 portion  252 , each of which is provided between the third mating base  231  and the mating portion. In the example illustrated in  FIG. 5 , the 1st-3 mating portion  232  and the 2nd-3 mating portion  233  serve as the mating portion. 
     Regarding the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, at the junction between the second portion  251  and the 1st-3 mating portion  232 , the cross-sectional area size of the second portion  251  is larger than the cross-sectional area size of the 1st-3 mating portion  232 . Instead of the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, the cross-sectional area size of a section parallel to a plane intersecting with but not perpendicular to the first axis may be used. In this example, the first axis is parallel to the Z axis. The shape of the 2nd-3 mating portion  233  and the shape of its 2nd-2 portion  252  are the same as the shape of the 1st-3 mating portion  232  and the shape of its second portion  251 , respectively. 
       FIG. 6  is an external perspective view illustrating the schematic structure of a 1st-4 packing portion  311  of a packing device according to another variation example.  FIG. 7  is an external perspective view illustrating the schematic structure of a 1st-4 mating portion  332  of the 1st-4 packing portion  311  of the packing device according to the variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 6 and 7 . The 1st-4 packing portion  311  includes a fourth mating base  331 , the 1st-4 mating portion  332 , and a 2nd-4 mating portion  333 . The 1st-4 mating portion  332  has a first non-sloped surface  351  at a part of its sloped surface that is inclined with respect to the first axis. The 2nd-4 mating portion  333  has a second non-sloped surface  352  at a part of its sloped surface that is inclined with respect to the first axis. In this example, the first axis is parallel to the Z axis. The 1st-4 packing portion  311  is another example of a first packing portion. The fourth mating base  331  is an example of a base. Each of the 1st-4 mating portion  332  and the 2nd-4 mating portion  333  is an example of a mating portion. Each of the first non-sloped surface  351  and the second non-sloped surface  352  is an example of a non-sloped surface. 
     The structure of the 1st-4 packing portion  311  is, roughly speaking, the same as the structure of the first packing portion  11  illustrated in  FIGS. 1 to 3  except that the 1st-4 packing portion  311  has the first non-sloped surface  351  and the second non-sloped surface  352 . However, the shape and size of each portion constituting its structure may be adjusted appropriately, as may be necessary for providing the first non-sloped surface  351  and the second non-sloped surface  352 . 
     In the example illustrated in  FIGS. 6 and 7 , it may be interpreted that, in the 1st-4 mating portion  332 , the first non-sloped surface  351  is provided at an area between two sloped surface areas located adjacent thereto. Although the first non-sloped surface  351  provided on the negative X-directional side is illustrated in the example of  FIGS. 6 and 7 , a similar non-sloped surface is provided on the positive X-directional side, too (though not illustrated). The shape of the 2nd-4 mating portion  333  and the shape of its second non-sloped surface  352  are the same as the shape of the 1st-4 mating portion  332  and the shape of its first non-sloped surface  351 , respectively. 
     With reference to  FIGS. 8 and 9 , a relationship between forces regarding mating in a second packing device  101  according to an exemplary embodiment will now be explained.  FIGS. 8 and 9  are diagrams for explaining a relationship between forces regarding mating in a second packing device  101  according to an exemplary embodiment. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 8 and 9 . In the example illustrated in  FIGS. 8 and 9 , to facilitate an explanation, an example of a packing device is referred to as the second packing device  101 . 
       FIGS. 8 and 9  depict a relationship between forces while taking, as an example, the second packing device  101  having the 1st-2 packing portion  111  illustrated in  FIG. 4 . However, the physical principle is the same also for other packing devices. The second packing device  101  includes the 1st-2 packing portion  111  and a 2nd-2 packing portion  112 . The 1st-2 packing portion  111  includes the 1st-2 mating portion  132  and its first portion  151 . The 2nd-2 packing portion  112  includes a second mating receptacle base  171  and its 1st-2 mating receptacle portion  172 . The 2nd-2 packing portion  112  is another example of a second packing portion. The second mating receptacle base  171  is an example of a base. The 1st-2 mating receptacle portion  172  is an example of a mating receptacle portion. 
     In  FIG. 8 , a mated state, in which the 1st-2 mating portion  132  has been fitted into the 1st-2 mating receptacle portion  172 , is illustrated. To facilitate an explanation, in  FIG. 8 , a cross section parallel to the X-Z plane of the second packing device  101  is schematically illustrated. In the example illustrated in  FIG. 8 , the 1st-2 mating portion  132  and the 1st-2 mating receptacle portion  172  mate with each other with a predetermined clearance left between the head surface of the 1st-2 mating portion  132  and the bottom surface of the 1st-2 mating receptacle portion  172 , instead of a complete fit of the 1st-2 mating portion  132  into the 1st-2 mating receptacle portion  172 . In the example illustrated in  FIG. 8 , the 1st-2 mating portion  132  and the 1st-2 mating receptacle portion  172  are fixed in this mated state. In the example illustrated in  FIG. 8 , the head surface of the 1st-2 mating portion  132  is the surface oriented in the negative direction of the Z axis, and the bottom surface of the 1st-2 mating receptacle portion  172  is the surface oriented in the positive direction of the Z axis. 
     A pulling force F 11  is illustrated in  FIG. 8 . The pulling force F 11  is a force for pulling the 1st-2 mating portion  132  out of the 1st-2 mating receptacle portion  172  from the mated state, in which the 1st-2 mating portion  132  has been fitted into the 1st-2 mating receptacle portion  172 . In this example, the direction of the force F 11  is parallel to the first axis. In this example, the first axis is parallel to the Z axis. The cross-sectional area size of a section, of the first portion  151 , parallel to the X-Y plane is denoted as A. A contact portion R 1  of the sloped surface on the positive X-directional side of the 1st-2 mating portion  132  and the sloped surface on the positive X-directional side of the 1st-2 mating receptacle portion  172  is illustrated in  FIG. 8 . These sloped surfaces are in contact with each other. 
     A relationship between forces at the contact portion R 1  is illustrated in  FIG. 9 . Let μ be a coefficient of friction at a certain point of contact in the contact portion R 1  along the sloped surface when in a stationary state. Let θ be an angle between the sloped surface and the direction parallel to the first axis. Let F 3  be a reactive force that is parallel to the direction perpendicular to the sloped surface and opposed to a force acting from the 1st-2 mating portion  132  to the 1st-2 mating receptacle portion  172 . Given these definitions, a force F 1 , which is a frictional force along the sloped surface, can be expressed as follows: F 1 =μ·F 3 . A force F 2 , which is a frictional force component in the direction parallel to the first axis, can be expressed as follows: F 2 =μ·F 3 ·cos θ. 
     The condition under which it is impossible to pull the 1st-2 mating portion  132  out of the 1st-2 mating receptacle portion  172  when the pulling force F 11  for pulling the 1st-2 mating portion  132  out of the 1st-2 mating receptacle portion  172  is applied can be expressed as follows: μ·F 3 ·cos θ&gt;F 11 . That is, the condition can be transformed as follows: cos θ&gt;F 11 /(μ·F 3 ). If the maximum value of the force F 11  is defined as A·σ, the condition can be expressed as follows: cos θ&gt;(A·σ)/(μ·F 3 ). In this example, a range within which the breakage of the first portion  151  does not occur is assumed, and σ in the formula denotes the minimum value at which the breakage of the first portion  151  occurs. Based on the relationship derived from this formula among the force F 3 , the cross-sectional area size A, and the angle θ, it is possible to design each value. The force σ and the coefficient of friction μ may be determined based on, for example, the material of the 1st-2 mating portion  132  and the material of the 1st-2 mating receptacle portion  172 , etc. An example of the numerical value of the coefficient of friction μ is approximately 0.6. An example of the numerical value of the force σ is approximately 0.15 MPa. The force F 3  can be adjusted by adjusting the magnitude of a force with which the 1st-2 mating portion  132  is pushed into the 1st-2 mating receptacle portion  172 , or by adjusting the amount of pushing. 
     As explained above, in the present embodiment, the mating strength of the mating portion and the mating receptacle portion is determined by a manner of inclination of the sloped surface. For example, the mating strength of the mating portion and the mating receptacle portion depends on the contact area size of the mating portion and the mating receptacle portion in the mated state of the mating portion and the mating receptacle portion. The contact area size includes, for example, contact area size on the sloped surface provided on at least one of the mating portion and the mating receptacle portion. In the present embodiment, the mating receptacle portion is configured to be widened by the mating portion as the mating portion makes its way into the mating receptacle portion during the insertion process. By this means, the mating portion and the mating receptacle portion become fixed to each other. 
     When the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion, either one of the 1st-2 packing portion  111  and the 2nd-2 packing portion  112 , or both, may be configured to break, for example. According to this structure, once the mating portion and the mating receptacle portion mate with each other, the mating portion and the mating receptacle portion will never be separated from each other unless the second packing device  101  is broken. Since separation without breakage is impossible, it is practically impossible to put the mating portion and the mating receptacle portion back into a “before-mating” state after the mating portion mates with the mating receptacle portion. For example, by adjusting the cross-sectional area size of a section of the first portion  151  parallel to the X-Y plane, the first portion  151  may be designed to break when the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion. 
     As another example, the 1st-2 packing portion  112  and the 2nd-2 packing portion  111  may be configured not to break when the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion. This structure makes it possible to put the mating portion and the mating receptacle portion back into a “before-mating” state after the mating portion mates with the mating receptacle portion. Therefore, this structure makes it possible to reuse the second packing device  101 . 
     The contact area size of the mating portion and the mating receptacle portion may be adjusted by, for example, adjusting the shape, etc. of the mating portion, or by adjusting the shape, etc. of the mating receptacle portion, or by adjusting both the shape, etc. of the mating portion and the shape, etc. of the mating receptacle portion. The pulling force that is required when the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion can be adjusted by adjusting the size of the part having the sloped surface, of the mating portion or of the mating receptacle portion, and by adjusting the magnitude of a pushing force with which the mating portion is inserted into the mating receptacle portion, or by adjusting a pushing amount by which the mating portion is inserted into the mating receptacle portion. The size of the part having the sloped surface may be, for example, the size of the contact area at which the mating portion and the mating receptacle portion are in contact with each other. 
     For example, if the sloped surface of the mating portion or the mating receptacle portion is tapered, the pulling force that is required when the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion becomes greater as the angle of inclination of the sloped surface with respect to the first axis becomes smaller. Therefore, if the mating portion and the mating receptacle portion are to be separable from each other without destroying the second packing device  101 , for example, the cross-sectional area size of a section of the first portion  151  parallel to the X-Y plane is increased as the angle of inclination of the sloped surface with respect to the first axis decreases. Incidentally, the larger the angle of inclination of the sloped surface with respect to the first axis is, the gentler the slope is. 
     For example, the tensile fracture strength of a foamed plastic cushioning material is lower than its compressive fracture strength. By utilizing this property, it is possible to adopt a structure that makes it impossible to separate the mating portion and the mating receptacle portion from each other without destroying the second packing device  101  after the mating portion and the mating receptacle portion are assembled into a mated state. Whether the second packing device  101  will break when the mating portion is pulled out of the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion or not can be predestined by, for example, adjusting the cross-sectional area size of a section parallel to the X-Y plane, of a predetermined part that is relatively close to the base of the mating portion or the mating receptacle portion. The predetermined part may be, for example, the first portion  151 . 
     In the present embodiment, once the shape of the mating portion and the shape of the mating receptacle portion are given, it is possible to determine, by design, a pushing amount that will be required at the time of push-mating and a pulling force that will be required at the time of pulling. When the mating portion and the mating receptacle portion are in the mated state, for example, the head of the protrusion of the mating portion may be in contact with the bottom of the hole of the mating receptacle portion; alternatively, there may be a clearance therebetween without contact. A mark that indicates how deep the mating portion should be fitted into the mating receptacle portion may be provided on either one of the mating portion and the mating receptacle portion, or both. The mark may be, for example, an alignment line that is provided on the mating portion and is to be aligned with a predetermined position of the mating receptacle portion when the mating portion is inserted into the mating receptacle portion. 
       FIG. 10  is a side view illustrating the schematic structure of a 1st-5 packing portion  411  of a packing device according to another variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 10 . The 1st-5 packing portion  411  is another example of a first packing portion. 
     The 1st-5 packing portion  411  includes a fifth mating base  431 , a 1st-5 mating portion  432 , and a third portion  451 . The third portion  451  is provided between the fifth mating base  431  and the 1st-5 mating portion  432 . The third portion  451  has a shape of a rectangular parallelepiped. Regarding the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, at the junction between the third portion  451  and the 1st-5 mating portion  432 , the cross-sectional area size of the third portion  451  is the same as the cross-sectional area size of the 1st-5 mating portion  432 . Instead of the cross-sectional area size of a section parallel to the X-Y plane, which is perpendicular to the first axis, the cross-sectional area size of a section parallel to a plane intersecting with but not perpendicular to the first axis may be used. In this example, the first axis is parallel to the Z axis. The fifth mating base  431  is an example of a base. The 1st-5 mating portion  432  is an example of a mating portion. 
     The structure of the 1st-5 packing portion  411  is, roughly speaking, the same as the structure of the first packing portion  11  illustrated in  FIGS. 1 to 3  except that the 1st-5 packing portion  411  has the third portion  451 . However, the shape and size of each portion constituting its structure may be adjusted appropriately, as may be necessary for providing the third portion  451 . The 1st-5 packing portion  411  may, for example, further include another mating portion in addition to the 1st-5 mating portion  432 . A third portion that is similar to, for example, the third portion  451  of the 1st-5 packing portion  411  may be provided for this additional mating portion. 
       FIG. 11  is a side view illustrating the schematic structure of a third packing device  501  according to another variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 11 . The third packing device  501  includes a 1st-6 packing portion  511  and a 2nd-3 packing portion  512 . The 1st-6 packing portion  511  includes a sixth mating base  531  and a 1st-6 mating portion  532 . The 2nd-3 packing portion  512  includes a 1st-3 mating receptacle portion  572  formed in a third mating receptacle base  571 . In the example illustrated in  FIG. 11 , to facilitate an explanation, an example of a packing device is referred to as the third packing device  501 . The 1st-6 packing portion  511  is another example of a first packing portion. The 2nd-3 packing portion  512  is another example of a second packing portion. The sixth mating base  531  is an example of a base. The 1st-6 mating portion  532  is an example of a mating portion. The third mating receptacle base  571  is an example of a base. The 1st-3 mating receptacle portion  572  is an example of a mating receptacle portion. 
     The 1st-6 mating portion  532  has a stepped structure of three levels of plane parallel to the X-Y plane, rising in the direction parallel to the first axis. The 1st-6 mating portion  532  has a first step portion  533 , a second step portion  534 , and a third step portion  535 , each of which is a part of its stepped structure, in the positive direction along the Z axis. In this example, the first axis is parallel to the Z axis. Regarding the cross-sectional area size of a section parallel to the X-Y plane, the first step portion  533  is the smallest of the three, the second step portion  534  is the medium one, and the third step portion  535  is the largest of the three. Each of the first step portion  533 , the second step portion  534 , and the third step portion  535  is an example of a step. 
     The 1st-3 mating receptacle portion  572  has a stepped structure of two levels of plane parallel to the X-Y plane, rising in the direction parallel to the first axis. The 1st-3 mating receptacle portion  572  has a fourth step portion  573  and a fifth step portion  574 , each of which is a part of its stepped structure, in the positive direction along the Z axis. Regarding the cross-sectional area size of a section parallel to the X-Y plane, the fourth step portion  573  is smaller, and the fifth step portion  574  is larger. Each of the fourth step portion  573  and the fifth step portion  574  is an example of a step. 
     In the example illustrated in  FIG. 11 , the first step portion  533  and the second step portion  534  of the 1st-6 mating portion  532  mate with the fourth step portion  573  and the fifth step portion  574  of the 1st-3 mating receptacle portion  572  respectively. Although the 1st-3 mating receptacle portion  572  in the example illustrated in  FIG. 11  has a stepped structure of two levels, the number of steps may be three or more. 
       FIG. 12  is a side view illustrating the schematic structure of a fourth packing device  601  according to another variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 12 . The fourth packing device  601  includes a 1st-7 packing portion  611  and a 2nd-4 packing portion  612 . The 1st-7 packing portion  611  includes a seventh mating base  631  and a 1st-7 mating portion  632 . The 2nd-4 packing portion  612  includes a 1st-4 mating receptacle portion  672  formed in a fourth mating receptacle base  671 . In the example illustrated in  FIG. 12 , the 1st-7 mating portion  632  has a sloped surface that is inclined with respect to the first axis, and the 1st-4 mating receptacle portion  672  does not have a sloped surface that is inclined with respect to the first axis. In this example, the first axis is parallel to the Z axis. In the example illustrated in  FIG. 12 , to facilitate an explanation, an example of a packing device is referred to as the fourth packing device  601 . The 1st-7 packing portion  611  is another example of a first packing portion. The 2nd-4 packing portion  612  is another example of a second packing portion. The seventh mating base  631  is an example of a base. The 1st-7 mating portion  632  is an example of a mating portion. The fourth mating receptacle base  671  is an example of a base. The 1st-4 mating receptacle portion  672  is an example of a mating receptacle portion. 
     The structure of the fourth packing device  601  is, roughly speaking, the same as the structure of the first packing device  1  illustrated in  FIGS. 1 to 3  except for the shape of the 1st-7 mating portion  632  and the shape of the 1st-4 mating receptacle portion  672 . However, the shape and size of each portion constituting its structure may be adjusted appropriately if needed due to the different shape of the 1st-7 mating portion  632  and the different shape of the 1st-4 mating receptacle portion  672 . The 1st-7 packing portion  611  may, for example, further include another mating portion in addition to the 1st-7 mating portion  632 . Similarly, the 2nd-4 packing portion  612  may, for example, further include another mating receptacle portion in addition to the 1st-4 mating receptacle portion  672 . 
       FIG. 13  is a side view illustrating the schematic structure of a fifth packing device  701  according to another variation example. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in  FIG. 13 . The fifth packing device  701  includes a 1st-8 packing portion  711  and a 2nd-5 packing portion  712 . The 1st-8 packing portion  711  includes an eighth mating base  731  and a 1st-8 mating portion  732 . The 2nd-5 packing portion  712  includes a 1st-5 mating receptacle portion  772  formed in a fifth mating receptacle base  771 . In the example illustrated in  FIG. 13 , the 1st-8 mating portion  732  does not have a sloped surface that is inclined with respect to the first axis, and the 1st-5 mating receptacle portion  772  has a sloped surface that is inclined with respect to the first axis. In this example, the first axis is parallel to the Z axis. In the example illustrated in  FIG. 13 , to facilitate an explanation, an example of a packing device is referred to as the fifth packing device  701 . The 1st-8 packing portion  711  is another example of a first packing portion. The 2nd-5 packing portion  712  is another example of a second packing portion. The eighth mating base  731  is an example of a base. The 1st-8 mating portion  732  is an example of a mating portion. The fifth mating receptacle base  771  is an example of a base. The 1st-5 mating receptacle portion  772  is an example of a mating receptacle portion. 
     The structure of the fifth packing device  701  is, roughly speaking, the same as the structure of the first packing device  1  illustrated in  FIGS. 1 to 3  except for the shape of the 1st-8 mating portion  732  and the shape of the 1st-5 mating receptacle portion  772 . However, the shape and size of each portion constituting its structure may be adjusted appropriately if needed due to the different shape of the 1st-8 mating portion  732  and the different shape of the 1st-5 mating receptacle portion  772 . The 1st-8 packing portion  711  may, for example, further include another mating portion in addition to the 1st-8 mating portion  732 . Similarly, the 2nd-5 packing portion  712  may, for example, further include another mating receptacle portion in addition to the 1st-5 mating receptacle portion  772 . 
     With reference to  FIGS. 14 to 20 , the packing of a printer  1011  will now be explained. Various packing devices, for example, those explained above with reference to  FIGS. 1  to  13 , can be used as a sixth packing device  1012  for the printer  1011 . In the example illustrated in  FIGS. 14 to 20 , to facilitate an explanation, an example of a packing device is referred to as the sixth packing device  1012 . 
     With reference to  FIGS. 14 to 16 , a method for manufacturing the printer  1011  packed on the sixth packing device  1012  will now be explained.  FIGS. 14, 15, and 16  are diagrams for explaining a method for manufacturing the printer  1011  packed on the sixth packing device  1012  according to an exemplary embodiment. To facilitate an explanation, in  FIGS. 14, 15, and 16 , a cross section parallel to the X-Z plane of the sixth packing device  1012  is schematically illustrated. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 14 to 16 . In the explanation given with reference to  FIGS. 14 to 16 , the positive direction along the Z axis is assumed to be vertically upward, and the negative direction along the Z axis is assumed to be vertically downward. The direction of gravity is vertically downward. 
     In the present embodiment, the printer  1011  packed on the sixth packing device  1012  is manufactured from a state illustrated in  FIG. 14  to a state illustrated in  FIG. 16  by going through a state illustrated in  FIG. 15 . The sixth packing device  1012  includes a 1st-9 packing portion  1014  and a 2nd-6 packing portion  1013 . In the example illustrated in  FIGS. 14 to 16 , to facilitate an explanation, a shape along a predetermined cross section parallel to the X-Z plane is illustrated as the shape of the 2nd-6 packing portion  1013 . The 1st-9 packing portion  1014  is another example of a first packing portion. The 2nd-6 packing portion  1013  is another example of a second packing portion. 
     First, the state illustrated in  FIG. 14  will now be explained. The 2nd-6 packing portion  1013  is placed on a first table  1071 . The printer  1011  is suspended in air by means of a first wire  1051  of a crane (not illustrated). The printer  1011  is lowered toward the 2nd-6 packing portion  1013  from above while being supported by the first wire  1051 . Then, the printer  1011  is placed onto the 2nd-6 packing portion  1013 . The first table  1071  is an example of a structural foundation. For example, the first table  1071  may be a pallet. The first table  1071  is configured using, for example, a cushioning material. The first table  1071  is, for example, configured to be able to be transported, with the forks of a forklift inserted. The first wire  1051  is an example of a wire. 
     Next, the state illustrated in  FIG. 15  will now be explained. The printer  1011  is placed on the 2nd-6 packing portion  1013 . In the state illustrated in  FIG. 15 , the first wire  1051  has been removed from the printer  1011 . The 2nd-6 packing portion  1013  accommodates a first installation portion  1031  and a first wall portion  1032  of the printer  1011 . The first installation portion  1031  is an example of an installation portion. 
     In the example illustrated in  FIGS. 14 to 16 , the first installation portion  1031  of the printer  1011  is a portion in the negative direction along the Z axis, and corresponds to the bottom. In the example illustrated in  FIGS. 14 to 16 , the first wall portion  1032  of the printer  1011  is a portion in the positive direction along the X axis, and corresponds to a side. The side may be, for example, the front or the rear. In the example illustrated in  FIGS. 14 to 16 , each of the first installation portion  1031  and the first wall portion  1032  of the printer  1011  is in contact with the 2nd-6 packing portion  1013 . 
     Next, the state illustrated in  FIG. 16  will now be explained. In a space in the negative direction along the X axis with respect to the printer  1011 , the 1st-9 packing portion  1014  is pushed down onto the 2nd-6 packing portion  1013  from above. Because of this pushing, the mating portion (not illustrated) of the 1st-9 packing portion  1014  mates with the mating receptacle portion (not illustrated) of the 2nd-6 packing portion  1013 . In the example illustrated in  FIGS. 14 to 16 , the mating portion of the 1st-9 packing portion  1014  protrudes in the negative direction along the Z axis, and the depth direction of the hole of the mating receptacle portion of the 2nd-6 packing portion  1013  is the negative direction along the Z axis. Because of this process, the 1st-9 packing portion  1014  is put in place to face a second wall portion  1033  of the printer  1011 . The 1st-9 packing portion  1014  is able to be put in place in contact with the second wall portion  1033  of the printer  1011 . For example, the 1st-9 packing portion  1014  may be in contact with the second wall portion  1033  of the printer  1011 , and may be not in contact therewith. When a structure in which the 1st-9 packing portion  1014  is not in contact with the second wall portion  1033  of the printer  1011  is adopted, a smaller clearance between them is advantageous. For example, a desirable structure is able to reduce the shake by contact of the second wall portion  1033  of the printer  1011  with the 1st-9 packing portion  1014  when the printer  1011  shakes. 
     The state illustrated in  FIG. 15  could be shaky because an upper portion of the printer  1011  is unsupported. In this respect, the mating of the 1st-9 packing portion  1014  with the 2nd-6 packing portion  1013  as illustrated in  FIG. 16  improves the stability of the printer  1011  in a packed state. Prior to transportation of the printer  1011  packed in this way, for example, the printer  1011  is enclosed by a predetermined box from above. In this covered state, the printer  1011  packed on the sixth packing device  1012  is transported. In the state illustrated in  FIG. 16 , the printer  1011  is stable also when the printer  1011  is moved inside a factory, etc. without being covered by such a box or when the box has been removed from the printer  1011  at the time of unpacking. 
     In the present embodiment, after lifting the printer  1011  by means of the first wire  1051  of the crane and then lowering the printer  1011  onto the 2nd-6 packing portion  1013  for placement, the 1st-9 packing portion  1014  is mated with the 2nd-6 packing portion  1013 . On the other hand, the un-mating of the 1st-9 packing portion  1014  from the 2nd-6 packing portion  1013  is not always necessary, for example, if it is possible to take the printer  1011  out of the sixth packing device  1012  by tilting the printer  1011  while taking advantage of a clearance that exists around the printer  1011  when the 1st-9 packing portion  1014  and the 2nd-6 packing portion  1013  are in the mated state. 
     In the example illustrated in the present embodiment, regarding the height in the upward direction, the level of the part of the 2nd-6 packing portion  1013  in the negative direction along the X axis with respect to the printer  1011  is assumed to be the same as the level of the part of the 2nd-6 packing portion  1013  in the positive direction along the X axis with respect to the printer  1011 . These levels may be different from each other as another example. For example, the level of the part of the 2nd-6 packing portion  1013  in the positive direction along the X axis with respect to the printer  1011  may be higher than the level of the part of the 2nd-6 packing portion  1013  in the negative direction along the X axis with respect to the printer  1011 . 
     With reference to  FIGS. 17 to 20 , an example of the appearance of the printer  1011  packed on the sixth packing device  1012  will now be explained. Each of  FIGS. 17, 18, 19 , and  20  is a diagram that illustrates an example of the appearance of the printer  1011  packed on the sixth packing device  1012  according to an exemplary embodiment. To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 17 to 20 . In the explanation given with reference to  FIGS. 17 to 20 , the positive direction along the Z axis is assumed to be vertically upward, and the negative direction along the Z axis is assumed to be vertically downward. The direction of gravity is vertically downward. 
       FIG. 17  illustrates an example of the appearance of the printer  1011  as viewed in the negative direction along the Y axis. In the example illustrated in  FIG. 17 , to facilitate an explanation, a shape along a predetermined cross section parallel to the X-Z plane is illustrated as the shape of the 2nd-6 packing portion  1013 . 
       FIG. 18  illustrates an example of the appearance of the printer  1011  packed on the sixth packing device  1012 . In the example illustrated in  FIG. 18 , the sixth packing device  1012  includes a combination of the 1st-9 packing portion  1014  and the 2nd-6 packing portion  1013  on its side in the negative direction along the Y axis and a combination of a 1st-10 packing portion  1016  and a 2nd-7 packing portion  1015  on its side in the positive direction along the Y axis. These two combinations are symmetrical in the direction along the Y axis. Although the two combinations are assumed to be separate from each other in this example in order to facilitate an explanation, the two combinations may be configured integrally. The 1st-9 packing portion  1014  faces the second wall portion  1033  of the printer  1011 . The 1st-10 packing portion  1016  faces a 2nd-2 wall portion  1034  of the printer  1011 . The 1st-10 packing portion  1016  is another example of a first packing portion. The 2nd-7 packing portion  1015  is another example of a second packing portion. The 2nd-2 wall portion  1034  is an example of a second wall portion. 
       FIG. 19  illustrates an example of the appearance of the printer  1011  packed on the sixth packing device  1012 . To facilitate an explanation, in  FIG. 19 , an example of the appearance, with the combination of the 1st-9 packing portion  1014  and the 2nd-6 packing portion  1013  removed, is illustrated. 
       FIG. 20  illustrates an example of the appearance of the printer  1011  packed on the sixth packing device  1012 , with a first top cover  1091  and a second top cover  1092  on the top of the printer  1011 . Each of the first top cover  1091  and the second top cover  1092  is an example of a cover portion. In the example illustrated in  FIG. 20 , the first top cover  1091  is provided on the side in the negative direction along the Y axis, and the second top cover  1092  is provided on the side in the positive direction along the Y axis. These two top covers are symmetrical in the direction along the Y axis. In this example, the two top covers are assumed to be separate from each other. However, as another example, the two top covers may be configured integrally. The state of the printer  1011  illustrated in  FIG. 20  is, for example, a shipment state of the printer  1011  as a product. 
     With reference to  FIGS. 21 to 27 , the packing of a sheet transportation apparatus  2011  will now be explained. Various packing devices, for example, those explained above with reference to  FIGS. 1 to 13 , can be used as a seventh packing device  2012  for the sheet transportation apparatus  2011 . To facilitate an explanation, an XYZ orthogonal coordinate system, which is a three-dimensional coordinate system, is shown in each of  FIGS. 21 to 27 . In the explanation given with reference to  FIGS. 21 to 27 , the positive direction along the Z axis is assumed to be vertically upward, and the negative direction along the Z axis is assumed to be vertically downward. The direction of gravity is vertically downward. In the example illustrated in  FIGS. 21 to 27 , to facilitate an explanation, an example of a packing device is referred to as the seventh packing device  2012 . 
     The sheet transportation apparatus  2011  may be, for example, a finisher. The sheet transportation apparatus  2011  has a special shape, for example, and the center of gravity of the sheet transportation apparatus  2011  is often at a high position in the direction of gravity when installed in a state for use. As an example, the sheet transportation apparatus  2011  has a height of approximately 1,200 mm and a weight of approximately 100 kg. Accordingly, the center of gravity of the sheet transportation apparatus  2011  is at a high position. 
     In the present embodiment, roughly speaking, the packing of the sheet transportation apparatus  2011  is the same as the packing of the printer  1011  explained with reference to  FIGS. 14 to 20 , except for the difference between the shape of the printer  1011  and the shape of the sheet transportation apparatus  2011 . 
       FIGS. 21, 22, and 23  are diagrams for explaining a method for manufacturing the sheet transportation apparatus  2011  packed on the seventh packing device  2012  according to an exemplary embodiment. To facilitate an explanation, in  FIGS. 21, 22, and 23 , a cross section parallel to the X-Z plane of the seventh packing device  2012  is schematically illustrated. An explanation of  FIGS. 21, 22, and 23  regarding the sheet transportation apparatus  2011  is the same as an explanation of  FIGS. 14, 15, and 16  regarding the printer  1011 . Therefore, a detailed explanation is omitted. 
       FIGS. 21, 22, and 23  illustrate the sheet transportation apparatus  2011 , a second wire  2051  for suspension of the sheet transportation apparatus  2011 , a second table  2071 , and the seventh packing device  2012  including a 1st-11 packing portion  2014  and a 2nd-8 packing portion  2013 .  FIGS. 21, 22, and 23  further illustrate a second installation portion  2031  of the sheet transportation apparatus  2011 , a 1st-2 wall portion  2032  of the sheet transportation apparatus  2011 , and a 2nd-3 wall portion  2033  of the sheet transportation apparatus  2011 . The 1st-11 packing portion  2014  is another example of a first packing portion. The 2nd-8 packing portion  2013  is another example of a second packing portion. The second installation portion  2031  is an example of an installation portion. The 1st-2 wall portion  2032  is an example of a first wall portion. The 2nd-3 wall portion  2033  is an example of a second wall portion. The second wire  2051  is an example of a wire. 
     Each of  FIGS. 24, 25, 26, and 27  is a diagram that illustrates an example of the appearance of the sheet transportation apparatus  2011  packed on the seventh packing device  2012  according to an exemplary embodiment. An explanation of  FIGS. 24, 25, 26, and 27  regarding the sheet transportation apparatus  2011  is the same as an explanation of  FIGS. 17, 18, 19, and 20  regarding the printer  1011 . Therefore, a detailed explanation is omitted. 
       FIGS. 24 to 27  illustrate those illustrated in  FIGS. 21, 22, and 23 , another combination made up of a 1st-12 packing portion  2016  and a 2nd-9 packing portion  2015 , a 2nd-4 wall portion  2034  of the sheet transportation apparatus  2011  facing the 1st-12 packing portion  2016 , and two top covers, specifically, a third top cover  2091  and a fourth top cover  2092 . The 1st-12 packing portion  2016  is another example of a first packing portion. The 2nd-9 packing portion  2015  is another example of a second packing portion. The 2nd-4 wall portion  2034  is an example of a second wall portion. 
     Various packing devices explained with reference to  FIGS. 1 to 27  above are described collectively below. In the packing device according to the present embodiment, it is possible to adjust the mating strength when the mating portion and the mating receptacle portion mate with each other. Therefore, in the packing device according to the present embodiment, appropriate mating strength of the mating portion and the mating receptacle portion is achieved. In the packing device according to the present embodiment, it is possible to set the magnitude of a pushing force with which the mating portion is push-inserted into the mating receptacle portion, or a pushing amount thereof, or the magnitude of a pulling force with which the mating portion is pulled out of the mating receptacle portion, etc., by designing the shape of the mating portion and the shape of the mating receptacle portion. In the packing device according to the present embodiment, it is possible to design a structure that allows the mating portion to be pulled out of the mating receptacle portion without destroying the packing device from the mated state of the mating portion and the mating receptacle portion, or a structure that makes it impossible for the mating portion to be pulled out of the mating receptacle portion without destroying the packing device from the mated state of the mating portion and the mating receptacle portion. This makes it possible to design the packing device as a device that can be used only once or as a reusable device. 
     In general, to join two pads together, an adhesive, an adhesive tape such as a single-sided adhesive tape or a double-sided adhesive tape, or a fixing band is used. In the packing device according to the present embodiment, it is possible to fix the mating portion and the mating receptacle portion by mating without using any of them. In the packing device according to the present embodiment, by utilizing the elasticity and friction of the mating portion and the mating receptacle portion, for example, it is possible to achieve secure fixing without using any other member that is different from the first packing portion and the second packing portion. 
     For example, if the entirety of the packing device is made of the same material, trash separation is unnecessary when the packing device is thrown away. Although the packing device may be made of two or more different kinds of material, trash separation is required when it is discarded as industrial waste in some cases. Although an adhesive may be used for producing the packing device, the packing device formed using the adhesive is required in some cases to be treated as industrial waste because it is regarded as being formed by combining different kinds of material together. If a corrugated cardboard or a tape is used for producing the packing device, it might be impossible to achieve secure fixing. If a tape is used for producing the packing device, for example, the strength of fixing or the method of putting portions together might differ from person to person who performs the production work. 
     The sloped surface, which either one of the mating portion of the first packing portion and the mating receptacle portion of the second packing portion constituting the packing device has, or both have, may be a tapered inclined surface or a curved surface. The tapered inclined surface may have, for example, two levels or more of inclination. Each of the mating portion and the mating receptacle portion may have an arbitrary shape. For example, a surface intersecting with the direction of mating of the mating portion and the mating receptacle portion may have a + shape or an H shape or the like. Either one or both of the mating portion and the mating receptacle portion may have a partially thin shape or a partially thick shape, or may have a shape of varying in the angle of inclination at a part of the sloped surface. The first packing portion and the second packing portion may have plural combinations of the mating portion and the mating receptacle portion. In such a case, for example, total mating strength obtained from all of the combinations may be designed to be sufficiently high although individual mating strength obtained from each combination is not so high. 
     The printer may be any type of printing apparatus. For example, the printer may be a laser printer. 
     As described above, a packing device for a printer, or for a sheet transportation apparatus, according to the present embodiment has the following structure. 
     A packing device includes: a first packing portion that has a mating portion; and a second packing portion that has a mating receptacle portion configured to mate with the mating portion by inserting at least a part of the mating portion into the mating receptacle portion. At least one of the mating portion and the mating receptacle portion has a sloped surface that is inclined with respect to a first axis extending in a direction in which the mating portion and the mating receptacle portion mate. Therefore, in the packing device according to the present embodiment, it is possible to adjust the mating strength when the mating portion and the mating receptacle portion mate with each other. 
     In the packing device according to a certain structure example, the first packing portion further has a base, which supports the mating portion, and a first portion, which is provided between the base and the mating portion, and regarding cross-sectional area size of a section intersecting with the first axis, at a junction between the first portion and the mating portion, the cross-sectional area size of the first portion is smaller than the cross-sectional area size of the mating portion. Therefore, for example, it is possible to design the packing device as a non-reusable device by designing the first portion to break when the mating portion is separated from the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion. Other designs may be adopted. 
     In the packing device according to a certain structure example, the first packing portion further has a base, which supports the mating portion, and a second portion, which is provided between the base and the mating portion, and regarding cross-sectional area size of a section intersecting with the first axis, at a junction between the second portion and the mating portion, the cross-sectional area size of the second portion is larger than the cross-sectional area size of the mating portion. Therefore, for example, it is possible to design the packing device as a reusable device by designing the second portion not to break when the mating portion is separated from the mating receptacle portion from the mated state of the mating portion and the mating receptacle portion. Other designs may be adopted. 
     In the packing device according to a certain structure example, the mating strength of the mating portion and the mating receptacle portion is determined by a manner of inclination of the sloped surface. Therefore, it is possible to adjust the mating strength of the mating portion and the mating receptacle portion by designing the manner of inclination of the sloped surface. 
     In the packing device according to a certain structure example, the first packing portion and the second packing portion are made of a foamed plastic cushioning material. Therefore, it is possible to realize a packing device using a foamed plastic cushioning material as an advantageous example of its material. 
     In the present embodiment, a printer including a packing device can be provided. In a certain structure example, one of the first packing portion and the second packing portion accommodates an installation portion and a first wall portion of the printer, and the other of the first packing portion and the second packing portion faces a second wall portion of the printer and mates with the one of the first packing portion and the second packing portion. Therefore, it is possible to realize a printer including a packing device suitable for transportation or shipment, etc. of the printer. 
     In the present embodiment, a sheet transportation apparatus including a packing device can be provided. In a certain structure example, one of the first packing portion and the second packing portion accommodates an installation portion and a first wall portion of the sheet transportation apparatus, and the other of the first packing portion and the second packing portion faces a second wall portion of the sheet transportation apparatus and mates with the one of the first packing portion and the second packing portion. Therefore, it is possible to realize a sheet transportation apparatus including a packing device suitable for transportation or shipment, etc. of the sheet transportation apparatus. 
     In the present embodiment, a method for manufacturing a printer packed on a packing device can be provided. Therefore, it is possible to manufacture a printer packed on a packing device suitable for transportation or shipment, etc. of the printer. 
     In the present embodiment, a method for manufacturing a sheet transportation apparatus packed on a packing device can be provided. Therefore, it is possible to manufacture a sheet transportation apparatus packed on a packing device suitable for transportation or shipment, etc. of the sheet transportation apparatus. 
     Though exemplary embodiments of the present disclosure are explained in detail above with reference to the accompanying drawings, variations of specific structure are not limited to those described and illustrated in the embodiments. The scope of the present disclosure encompasses design, etc. that is within a range not departing from the gist of the disclosed technique.