Patent Publication Number: US-9833827-B2

Title: Stamping device and stamping method

Description:
The present application claims priority from Japanese Patent Application No. 2014-079138 filed on Apr. 8, 2014, which is incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a stamping device and a stamping method that forms a desired stamp image on a surface of a processing target by stamping. 
     2. Description of the Related Art 
     Conventionally, a stamping device is known that forms a desired image, for example, a photo image, a two-dimensional symbol or the like by forming a plurality of dot-shaped stamping indentations on a surface of a processing target formed of, for example, a metal material that is plastically deformable relatively easily such as gold, platinum, brass, aluminum, stainless steel or the like, or a resin material such as acrylic resin or the like. An example of the two-dimensional symbol is a two-dimensional code including squares called “cells” arrayed in a matrix; specifically, a QR code (registered trademark), a data matrix or the like. Such a stamping device stamps a tip of a needle-shaped processing tool on a surface of a processing target secured by a securing jig, so that a plurality of dot-shaped stamping indentations are formed on the surface. 
     A two-dimensional symbol is formed on a surface of a steel tool for medical uses such as, for example, a knife, a clamp or the like by use of such a stamping device as follows. First, the steel tool for medical uses, on which the two-dimensional symbol is to be formed, is secured to a securing jig while being positioned. Then, various settings are made regarding the stamping force by which stamping is to be performed on the surface of a processing target (more specifically, the steel tool for medical uses described above) by a processing tool, the size of an image to be formed by the stamping (stamp image) and the like. After the settings, data used to perform the stamping (stamping data) is created based on data representing the two-dimensional symbol and the various settings that have been input to, for example, a microcomputer of the stamping device. When an instruction is issued to perform the stamping on the processing target, a stamping head having the processing tool attached thereto is controlled by the microcomputer so that the stamping is performed on the surface of the processing target. Thus, a stamp image such as the two-dimensional symbol is formed on the surface of the processing target. The processing target is positioned by fine-adjusting the position of the securing jig or the position of the processing target such that a central position of an area of the surface of the processing target on which the stamp image is to be formed is irradiated with light from a laser pointer. 
     However, with the above-described conventional stamping device, even when the processing target is positioned by use of a laser pointer or the like, there are cases where the stamp image such as the two-dimensional symbol is not formed at an appropriate position on the surface of the processing target. More specifically, there are cases where the stamp image extends beyond a desired stamping area, or the shape of the stamp image is distorted and thus cannot be recognized. 
     When the stamp image cannot be formed inside the desired stamping area, the surface of the processing target having the stamp image formed thereon is ground by a grinder or the like to erase the stamp image. Then, the processing target is positioned again, and the stamp image such as the two-dimensional symbol or the like is formed again. Until the stamp image is formed inside the desired stamping area, the above-described process of positioning of the processing target, performing the stamping, and erasing the stamp image is repeated. An unexperienced operator often performs such a process repeatedly. This is time-consuming and often decreases the operation efficiency. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention provide a stamping device and a stamping method allowing even an unexperienced operator to easily perform stamping on a processing target. 
     A stamping device according to a preferred embodiment of the present invention performs stamping on a surface of a processing target. The stamping device includes a processing tool located to be movable at least upward and downward; a stamping data generator configured to create stamping data usable to form a stamp image on the surface of the processing target, based on image data corresponding to the stamp image; a positioning data generator configured to create positioning data usable to position the processing target, based on the stamping data; and a controller configured or programmed to control an operation of the processing tool. The controller includes a first controller configured or programmed to control the processing tool such that stamping is performed, based on the positioning data at a first stamping energy, on the processing target in a state of having a protective sheet attached thereto, the protective sheet being attached to a predetermined area including a stamping area where the stamp image is to be formed; and a second controller configured or programmed to control the processing tool such that stamping is performed, based on the stamping data at a second stamping energy which is equal to or different from the first stamping energy, on the processing tool in a state of having the protective sheet peeled off therefrom. 
     The positioning data represents a plurality of stamping indentations for positioning on an outermost line of the stamping area. 
     The stamping area is square or rectangular, and the image data represents a two-dimensional symbol that is to be formed in the stamping area; the stamping data generator configured or programmed to create the stamping data based on the image data representing the two-dimensional symbol; and the positioning data generator configured or programmed to create positioning data representing a plurality of stamping indentations for positioning on a horizontal line in the stamping area and a plurality of stamping indentations for positioning on a vertical line that is vertical to the horizontal line and is in the stamping area. 
     The positioning data generator is configured or programmed to create positioning data representing a plurality of stamping indentations for positioning on each of outermost horizontal lines in the stamping area and a plurality of stamping indentations for positioning on each of outermost vertical lines in the stamping area. 
     The positioning data generator is configured or programmed to create positioning data representing a stamping indentation for positioning at each of four corners of the stamping area, at least one stamping indentation for positioning on the horizontal line extending from each of the corners and at least one stamping indentation for positioning on the vertical line extending from each of the corners, the at least one stamping indentation for positioning on the horizontal line and the at least one stamping indentation for positioning on the vertical line being of the same number. 
     A total number of the stamping indentation for positioning at each of the corners, the at least one stamping indentation for positioning on the horizontal line extending from the each corner and the at least one stamping indentation for positioning on the vertical line extending from the each corner is seven. 
     The first controller is configured or programmed to control the processing tool such that the stamping is performed on the protective sheet but not on the processing target, based on the positioning data. 
     The protective sheet is softer than the processing target. 
     The protective sheet is made of a synthetic resin transparent adhesive tape. 
     The processing target is a steel medical tool. 
     A stamping method according to another preferred embodiment of the present invention performs stamping on a surface of a processing target by use of a processing tool movable at least upward and downward. The method includes a stamping data creation step of creating stamping data usable to form a stamp image on the surface of the processing target, based on image data corresponding to the stamp image; a positioning data creation step of creating positioning data usable to position the processing target, based on the stamping data; an attaching step of attaching a protective sheet to a predetermined area on the processing target that includes a stamping area where the stamp image is to be formed; a positioning step of controlling the processing tool such that stamping is performed, based on the positioning data at a first stamping energy, on the processing target in a state of having the protective sheet attached thereto; and a peeling step of peeling off the protective sheet from the processing target; and a stamping step of controlling the processing tool such that stamping is performed, based on the stamping data at a second stamping energy which is equal to or different from the first stamping energy, on the processing tool in a state of having the protective sheet peeled off therefrom. 
     The positioning data represents a plurality of stamping indentations for positioning formed on an outermost line of the stamping area. 
     The stamping area is square or rectangular, and the image data represents a two-dimensional symbol that is to be formed in the stamping area; in the stamping data creation step, the stamping data is created based on the image data representing the two-dimensional symbol; and in the positioning data creation step, positioning data is created representing a plurality of stamping indentations for positioning formed on a horizontal line in the stamping area and a plurality of stamping indentations for positioning formed on a vertical line that is vertical to the horizontal line and is in the stamping area. 
     In the positioning data creation step, positioning data is created to represent a plurality of stamping indentations for positioning formed on each of outermost horizontal lines in the stamping area and a plurality of stamping indentations for positioning formed on each of outermost vertical lines in the stamping area. 
     In the positioning data creation step, positioning data is created to represent a stamping indentation for positioning formed at each of four corners of the stamping area, at least one stamping indentation for positioning formed on the horizontal line extending from each of the corners and at least one stamping indentation for positioning formed on the vertical line extending from each of the corners, the at least one stamping indentation for positioning formed on the horizontal line and the at least one stamping indentation for positioning formed on the vertical line being of the same number. 
     Seven of the stamping indentations for positioning are created as a total of the stamping indentation for positioning formed at each of the corners, the at least one stamping indentation for positioning formed on the horizontal line extending from the each corner and the at least one stamping indentation for positioning formed on the vertical line extending from the each corner. 
     In the positioning step, the stamping is performed on the protective sheet but not on the processing target, based on the positioning data. 
     A material softer than the processing target is used for the protective sheet. 
     A synthetic resin transparent adhesive tape is used for the protective sheet. 
     A medical steel tool is the processing target. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially cut perspective view of a stamping device in a preferred embodiment according to the present invention. 
         FIG. 2  is a block diagram showing a functional structure of a microcomputer in a preferred embodiment according to the present invention. 
         FIG. 3A  shows an example of stamping indentations for positioning represented by positioning data in a preferred embodiment according to the present invention. 
         FIG. 3B  shows another example of stamping indentations for positioning represented by positioning data in a preferred embodiment according to the present invention. 
         FIG. 4  shows still another example of stamping indentations for positioning represented by positioning data in a preferred embodiment according to the present invention. 
         FIG. 5  shows a sheet stamping area of a protective sheet in a preferred embodiment according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in  FIG. 1 , X axis, Y axis and Z axis are perpendicular to one another. In  FIG. 1 , L refers to the left side of the X axis and R refers to the right side of the X axis. F refers to the front side of the Y axis and Re refers to the rear side of the Y axis. U refers to the up side of the Z axis and D refers to the down side of the Z axis. A stamping device  10  is placed on a plane defined by the X axis and the Y axis. The left side and the right side of the X axis are as seen from a person facing the stamping device  10 . The front side of the stamping device  10  that is defined by the Y axis is the side on which a processing target  200  is secured. These directions are defined merely for the sake of explanation, and do not limit in any way the form of installing the stamping device  10  according to various preferred embodiments of the present invention. 
     As shown in  FIG. 1 , the stamping device  10  in this preferred embodiment of the present invention preferably includes a housing  20 . The housing  20  includes a base member  12 , a rear member  14 , a side member  16 L, a side member  16 R, and a top member  18 . The rear member  14  is arranged vertically or substantially vertically on a rear portion of a top surface  12   a  of the base member  12 . The side member  16 L is secured to the rear member  14  and is arranged vertically or substantially vertically on a left portion of the base member  12 . Similarly, the side member  16 R is secured to the rear member  14  and is arranged vertically or substantially vertically on a right portion of the base member  12 . The top member  18  is provided on top ends of the rear member  14  and the side members  16 L and  16 R so as to face the base member  12 . 
     A stamping head  38  and a moving mechanism are provided above the base member  12 . The moving mechanism is configured to move the stamping head  38  three dimensionally, more specifically, in an X axis direction, a Y axis direction and a Z axis direction. The moving mechanism will be described later in detail. A securing jig  24  that secures the processing target  200  is detachably attached on a front portion of base member  12 . The processing target  200  is secured onto the securing jig  24 . In the present preferred embodiment, the processing target  200  preferably is a steel tool for medical uses such as, for example, a clamp, a knife or the like in this preferred embodiment, but many other targets may be used with various preferred embodiments of the present invention. 
     As shown in  FIG. 1 , the moving mechanism included in the stamping device  10  includes an elevation member  28 , a slidable member  32  and a carriage  36 . The elevation member  28  is slidable along guide rails  26   a  and  26   b  extending in the Z axis direction respectively in the vicinity of the side members  16 L and  16 R. The slidable member  32  is slidable along guide rails  30   a  and  30   b  extending in the Y axis direction below the elevation member  28 . The carriage  36  is slidable along guide rails  34   a  and  34   b  extending in the X axis direction between a left member and a right member of the slidable member  32 . The stamping head  38  is provided on the carriage  36 . A laser pointer  150  is provided on a top surface of the elevation member  28 . The laser pointer  150  directs light to a central or substantially central position of an area of a surface  200   a  of the processing target  200  on which stamping is to be performed. 
     The stamping head  38  includes a processing tool  58  and a holder  60  to which the stamping tool  58  is detachably attached. The processing tool  58  vibrates in the Z axis direction and forms a stamping indentation having a predetermined depth onto the surface  200   a  of the processing target  200 . The processing tool  58  is provided above the base member  12 . The overall operations including operations of moving the elevation member  28 , the slidable member  32  and the carriage  36 , a stamping operation performed on the surface  200   a  of the processing target  200  by the stamping head  38  and the like are controlled by a microcomputer  40  described later. 
     A stepping motor  42  controllable to be driven by the microcomputer  40  is provided on a bottom surface of the top member  18 . A Z-axis direction feed screw  44  is connected to the stepping motor  42 . A screw shaft of the Z-axis direction feed screw  44  on which a thread is provided extends in the Z axis direction. The screw shaft of the Z-axis direction feed screw  44  rotates about the Z axis direction when the stepping motor  42  is driven. The Z-axis direction feed screw  44  extends through a central or substantially central position of the elevation member  28 . A feed nut  46  is provided in a through-hole through which the Z-axis direction feed screw  44  extends. The Z-axis direction feed screw  44  is threaded with the feed nut  46 . In such a structure, when the stepping motor  42  is driven, the Z-axis direction feed screw  44  is rotated and thus the elevation member  28  moves upward and downward in the Z axis direction. 
     A stepping motor  48  controllable to be driven by the microcomputer  40  is provided at a rear end of the elevation member  28 . A Y-axis direction feed screw  50  is connected to the stepping motor  48 . A screw shaft of the Y-axis direction feed screw  50  on which a thread is provided extends in the Y axis direction. The screw shaft of the Y-axis direction feed screw  50  rotates about the Y axis direction when the stepping motor  48  is driven. The Y-axis direction feed screw  50  extends through a top rear portion of the slidable member  32 . A feed nut  52  is provided in a through-hole through which the Y-axis direction feed screw  50  extends. The Y-axis direction feed screw  50  is threaded with the feed nut  52 . In such a structure, when the stepping motor  48  is driven, the Y-axis direction feed screw  50  is rotated and thus the slidable member  32  moves forward and rearward in the Y axis direction. 
     A stepping motor  54  controllable to be driven by the microcomputer  40  is provided on a right front surface of the slidable member  32 . An X-axis direction feed screw  56  is connected to the stepping motor  54 . A screw shaft of the X-axis direction feed screw  56  on which a thread is provided extends in the X axis direction. The screw shaft of the X-axis direction feed screw  56  rotates about the X axis direction when the stepping motor  54  is driven. The X-axis direction feed screw  56  extends through a side surface of the carriage  36 . A feed nut (not shown) is provided in a through-hole through which the X-axis direction feed screw  56  extends. The X-axis direction feed screw  56  is threaded with the feed nut. In such a structure, when the stepping motor  54  is driven, the X-axis direction feed screw  56  is rotated and thus the carriage  36  moves rightward and leftward in the X axis direction. Thus, the carriage  36  is movable three-dimensionally by the stepping motors  42 ,  48  and  54 . 
     The securing jig  24  is detachably provided on the front portion of the base member  12  and secures the processing target  200 . The securing jig  24  has a structure configured to move the secured processing target  200  in the X axis direction and the Y axis direction. A specific structure of the securing jig  24  is disclosed in, for example, Japanese Laid-Open Patent Publication No. 2013-10154 and thus will not be described herein. 
     Now, with reference to  FIG. 2 , a functional structure of the microcomputer  40  will be described. The microcomputer  40  is configured or programmed to include a control unit  62 , a storage unit  64 , a positioning data creation unit  66 , and a stamping data creation unit  68 . The control unit  62  preferably includes a CPU (central processing unit). The control unit  62  is configured or programmed to include a first control unit  62   a  and a second control unit  62   b . The first control unit  62   a  and the second control unit  62   b  will be described in detail later. The storage unit  64  may include, for example, a memory. The CPU executes a predetermined program stored in a RAM (random access memory; not shown), so that the positioning data creation unit  66  and the stamping data creation unit  68  are functionally provided. 
     The control unit  62  executes, via the stepping motors  42 ,  48  and  54 , overall control of various elements of the stamping device  10  such as control of the movements of the elevation member  28 , the slidable member  32  and the carriage  36 , a control of a stamping force of the stamping head  38  on the surface  200   a  of the processing target  200 , and the like. The storage unit  64  stores various data set for the stamping force, the size of a stamp image or the like, image data representing a two-dimensional symbol or the like, stamping data representing the stamp image and the like, and positioning data described later. 
     The stamping data creation unit  68  creates stamping data usable to perform stamping on the surface  200   a  of the processing target  200 , based on the various set data and the image data stored. The positioning data creation unit  66  creates positioning data usable to position the processing target  200 , based on the stamping data. The positioning data is stored in the storage unit  64 . The positioning data preferably has a capacity that is smaller than that of the stamping data. Therefore, it is not time-consuming or labor-consuming to create the positioning data. 
     The positioning data created by the positioning data creation unit  66  is, for example, as follows. As shown in  FIG. 3A , the positioning data represents a plurality of stamping indentations SM for positioning. The stamping indentations SM for positioning are located in an area SR where a two-dimensional symbol SY having a star shape or the like, which is an example of a stamp image, is to be formed (hereinafter, this area will be referred to as a “stamping area”). Although the positioning data does not include the stamp image such as the two-dimensional symbol SY or the like,  FIG. 3A  shows the two-dimensional symbol SY for easier understanding. The stamping area SR may have any of various shapes preferably including a square shape, a rectangular shape, a circular shape, an elliptical shape and the like. In the example shown in  FIG. 3A , a plurality of stamping indentations SM for positioning are located at a prescribed interval on each of outermost horizontal lines HL and on each of outermost vertical lines VL of the stamping area SR. This will be described in more detail. A stamping indentation SM for positioning is located at each of four corners C of the stamping area SR. In addition, equal numbers of stamping indentations SM for positioning are located on a horizontal line HL and a vertical line VL extending from each corner C. A total number of the stamping indentation SM for positioning formed at each corner C, the plurality of stamping indentations SM for positioning formed on the horizontal line HL extending from the each corner C, and the plurality of stamping indentations SM for positioning formed on the vertical line VL extending from the each corner C preferably is seven, for example. The positioning data representing the stamping indentations SM for positioning shown in  FIG. 3A  represents 28 stamping indentations SM for positioning in total. 
     In this preferred embodiment, before stamping is performed on the processing target  200  by use of the stamping data, stamping is performed on the processing target  200  including a protective sheet  210  shown in  FIG. 1  attached thereto by use of the above-described positioning data. As shown in  FIG. 5 , the protective sheet  200   a  includes a sheet stamping area  210   a  corresponding to the stamping area SR provided therein. The sheet stamping area  210   a  is visually recognizable, and may be provided by marking or the like. For the protective sheet  210 , a transparent adhesive tape formed of, for example, a synthetic resin that is softer than the processing target  200  is preferably used. The protective sheet  210  preferably has a thickness of, for example, about 0.05 mm to about 0.3 mm. The protective sheet  210  is attached to a predetermined area of the processing target  200 . 
     For performing the stamping by use of the positioning data, the first control unit  62   a  controls the processing tool  58  such that the stamping is performed based on the positioning data at a first stamping energy on the processing target  200  in a state of having the protective sheet  210  attached thereto. The stamping at the first stamping energy is performed only on the protective sheet  210 , and does not reach the surface  200   a  of the processing target  200  that is below the protective sheet  210 . For performing the stamping by use of the stamping data, the second control unit  62   b  controls the processing tool  58  such that the stamping is performed based on the stamping data at a second stamping energy, which is equal to or different from the first stamping energy, on the processing target  200  in a state of having the protective sheet  210  peeled off therefrom. The “stamping energy” refers to a concept encompassing the stamping speed, the stamping force and the stamping stroke (also referred to as the “moving amount of stamping”) of the processing tool  58 . The stamping speed is lower at the stamping performed by use of the positioning data than at the stamping performed by use of the stamping data. The stamping force is weaker at the stamping performed by use of the positioning data than at the stamping performed by use of the stamping data. The stamping stroke is shorter at the stamping performed by use of the positioning data than at the stamping performed by use of the stamping data. The second stamping energy may be larger than the first stamping energy, the second stamping energy may be equal to the first stamping energy, or the second stamping energy may be smaller than the first stamping energy, depending on the size or the material of the processing target  200 . In the case where the protective sheet  210  is preferably made of a synthetic resin adhesive tape as described above, the first stamping energy is a fixed or substantially fixed value. 
     Hereinafter, a flow of stamping process will be described. For example, a non-limiting example of a method for forming the two-dimensional symbol SY as shown in  FIG. 3A  on the processing target  200  is as follows. First, various settings regarding the stamping force of the processing tool  58 , the size of the two-dimensional symbol SY, which is a stamp image, and the like are performed on the stamping device  10 . 
     Next, the image data representing the two-dimensional symbol SY is stored in the storage unit  64 . Then, based on the image data and the various set data stored in the storage unit  64 , the stamping data is created by the stamping data creation unit  68 . Based on the created stamping data, the positioning data is created by the positioning data creation unit  66 . 
     Next, an operator secures the processing target  200  having the protective sheet  210  attached thereto to the securing jig  24 . The position of the processing target  200  secured to the securing jig  24  is finely adjusted such that light from the laser pointer  150  is at a central position of the sheet stamping area  210   a  of the protective sheet  210 . When the operator operates an operating element or the like to issue an instruction to perform the stamping for positioning the processing target  200 , the control unit  62  controls the operations of the elevation member  28 , the slidable member  32 , the carriage  36 , and the stamping head  38  based on the positioning data stored in the storage unit  64  of the microcomputer  40 . The stamping is performed on the protective sheet  210  by using the positioning data. In this case, as described above, the stamping is performed at the first stamping energy under the control of the first control unit  62   a . Therefore, the stamping indentations for positioning are formed only on the protective sheet  210  and do not reach the surface  200   a  of the processing target  200 . 
     Next, the operator visually checks the stamping indentations for positioning formed on the protective sheet  210 . When the stamping indentations for positioning extend beyond the sheet stamping area  210   a , the position of the processing target  200  is adjusted by use of the securing jig  24 . Then, the operator peels off the protective sheet  210 , and attaches a new protective sheet  210 . Next, the stamping indentations for positioning are formed on the protective sheet  210  again. This process is repeated until the stamping indentations for positioning are located inside the sheet stamping area  210   a , in other words, until the stamping indentations for positioning do not extend beyond the sheet stamping area  210   a  anymore. 
     By contrast, when the stamping indentations for positioning are located inside the sheet stamping area  210   a  without extending beyond the sheet stamping area  210   a , the operator peels off the protective sheet  210  from the processing target  200 . Then, the operator operates an operating element or the like to issue an instruction to perform the stamping. When it is instructed to perform the stamping by the operator, the control unit  62  controls the operations of the elevation member  28 , the slidable member  32 , the carriage  36 , and the stamping head  38  based on the stamping data stored in the storage unit  64  of the microcomputer  40 . In this case, as described above, the stamping is performed at the second stamping energy by the control of the second control unit  62   b . As a result, the stamp image such as, for example, the two-dimensional symbol SY is formed on the surface  200   a  of the processing target  200 . 
     As described above, the stamping device  10  in this preferred embodiment preferably creates the positioning data usable to position the processing target  200  based on the stamping data that is created by use of the image data representing the two-dimensional symbol SY or the like. The processing target  200  including the protective sheet  210  attached thereto is secured to the securing jig  24 , and the stamping indentations for positioning are formed at the first stamping energy on the protective sheet  210  attached to the secured processing target  200 . When the stamping indentations for positioning formed on the protective sheet  210  extend beyond the sheet stamping area  210   a , the position of the processing target  200  is adjusted again. After a new protective sheet  210  is attached, the stamping indentations for positioning are formed again on the protective sheet  210 . By contrast, when the stamping indentations for positioning formed on the protective sheet  210  are inside the sheet stamping area  210   a , the stamp image is formed at the second stamping energy on the processing target  200  in a state of having the protective sheet  210  peeled off therefrom. The stamping at the first stamping energy is performed only on the protective sheet  210 . Therefore, even when the stamping indentations for positioning extend beyond the sheet stamping area  210   a , it is only necessary to peel off the protective sheet  210 . The process of grinding the stamp image by a grinder or the like, which is conventionally necessary, is not needed. Therefore, even an unexperienced operator is able to perform the stamping more easily and within a shorter time than with a conventional device. 
     In this preferred embodiment, as shown in  FIG. 3A , the plurality of stamping indentations SM for positioning are preferably formed at a plurality of positions inside the stamping area SR. This makes it easy for the operator to check the sheet stamping area  210   a  of the protective sheet  210 . Therefore, the operator can easily determine whether or not the stamping indentations SM for positioning formed by use of the positioning data extend beyond the sheet stamping area  210   a.    
     The above preferred embodiment may be modified as described in modifications (1) through (8) below. 
     (1) In the above preferred embodiment, seven stamping indentations SM for positioning in total, for example, preferably are formed at each of the four corners C and on the horizontal and vertical lines extending from the each corner C of the stamping area SR. The present invention is not limited to this. One stamping indentation SM for positioning may be formed at each of the four corners C of the stamping area SR. Alternatively, three, five, nine, or any other odd number of stamping indentations SM for positioning may be formed at each of the four corners C and on the horizontal and vertical lines extending from the each corner C of the stamping area SR. Still alternatively, two, four, six or any other even number of indentations SM for positioning may be formed. 
     (2) In the above preferred embodiment, the star-shaped two-dimensional symbol SY is preferably used as the stamp image. The present invention is not limited to this. The stamp image may have any other shape, for example, a circular shape, a triangular shape or the like. 
     (3) In the above preferred embodiment, when the stamping indentations for positioning formed on the protective sheet  210  based on the positioning data extend beyond the sheet stamping area  210   a , the operator preferably adjusts the position of the processing target  200  on the securing jig  24 . The present invention is not limited to this. The moving amount of the slidable member  32 , the carriage  36  or the like may be adjusted under the control of the control unit  62  of the microcomputer  40  such that the stamping indentations for positioning are located inside the sheet stamping area  210   a.    
     (4) In the above preferred embodiment, the microcomputer preferably creates the stamping data and also creates the positioning data based on the stamping data. The present invention is not limited to this. The stamping data and the positioning data may be created by a separate personal computer. The created stamping data and positioning data may be transferred to the microcomputer  40  by wired or wireless communication, or may be transferred to the microcomputer  40  via a storage medium, for example. The storage medium may be a semiconductor memory such as a ROM or the like, a hard disc, a CD (compact disc), a DVD (digital versatile disc) or the like. 
     (5) In the above preferred embodiment, as shown in  FIG. 3A , the plurality of stamping indentations SM for positioning preferably are formed in a portion of each horizontal line HL and in a portion of each vertical line VL inside the stamping area SR. The present invention is not limited to this. As shown in  FIG. 3B , the stamping indentations SM for positioning may be formed along the entirety of each horizontal line HL and the entirety of each vertical line VL. In  FIG. 3B , the horizontal lines HL and the vertical lines VL are omitted for easier understanding. 
     (6) In the above, as shown in  FIG. 3A  and  FIG. 3B , the stamping indentations SM for positioning are preferably formed on each of the outermost horizontal lines HL and each of the outermost vertical lines VL of the square stamping area SR. The present invention is not limited to this. For example, as shown in  FIG. 4 , the plurality of stamping indentations SM for positioning may be formed on a horizontal line HL and also on a vertical line VL passing a center of the stamping area SR. 
     (7) In the above preferred embodiment, the protective sheet  210  is preferably attached to the processing target  200  before the processing target  200  is secured to the securing jig  24 . The present invention is not limited to this. The protective sheet  210  may be attached to the processing target  200  after the processing target  200  is secured to the securing jig  24 . 
     (8) The above preferred embodiment and the modifications described in (1) through (7) above may be combined appropriately. 
     The terms and expressions used herein are for description only and are not to be interpreted in a limited sense. These terms and expressions should be recognized as not excluding any equivalents to the elements shown and described herein and as allowing any modifications encompassed in the scope of the claims. The present invention may be embodied in many various forms. This disclosure should be regarded as providing preferred embodiments of the principle of the present invention. These preferred embodiments are provided with the understanding that they are not intended to limit the present invention to the preferred embodiments described in the specification and/or shown in the drawings. The present invention is not limited to the preferred embodiments described herein. The present invention encompasses any embodiment including equivalent elements, modifications, deletions, combinations, improvements and/or alterations of various preferred embodiments based on the present disclosure. The elements of each claim should be interpreted broadly based on the terms used in the claim, and should not be limited to any of the preferred embodiments described in this specification or discussed during the prosecution of the present application. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.