Patent Publication Number: US-2019193390-A1

Title: Tablet mark printing method, tablet mark printing device, and tablet

Description:
TECHNICAL FIELD 
     The present invention relates to a tablet mark printing method, a tablet mark printing machine, and a tablet for making it easier to identify the splitting position of a tablet. 
     BACKGROUND ART 
     A tablet may have a splitting line on one of its main surfaces along which to split the tablet in half or in quarters in accordance with the requirements in administering the medicine. Such a splitting line is provided as a groove in the form of a straight line from one end to the other end of the tablet. The splitting line makes it relatively easy to split the tablet. 
     However, it is difficult in some cases to identify the splitting position because the splitting line on a surface of the tablet is not different in color from the part surrounding the splitting line and because there is no splitting line on the other main surface. Splitting a tablet is expected to take place when an individual who takes the tablet splits the tablet upon instruction by a doctor and when tablets are automatically split with a multi-dose packaging device that encloses a plurality of kinds of medicines in one packet. 
     Patent Literature 1 describes a configuration in which the splitting line part of a tablet is marked in a different color from that of the surrounding part to make it easier to split the tablet. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Laid-Open Patent Application Publication No. 2015-34133. 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, the technique described in Patent Literature 1 only applies marking on the tablet surface having a splitting line and is disadvantageous in that the splitting position cannot be identified when the surface without the splitting line is viewed. 
     An object of the present invention is to solve the above-described problem and to enable the splitting position of a tablet to be identified by visual observation or with a multi-dose packaging device even when the surface without the splitting line is viewed. 
     Solution to Problem 
     To solve the above-described problem, the present invention provides a tablet mark printing method of printing a mark on a splitting position of a tablet having a splitting line on a first surface and not having a splitting line on a second surface, the method including: performing splitting line position recognition to recognize a position of the splitting line on the first surface of the tablet; and printing the mark at a position corresponding to the position of the splitting line at least on the second surface. 
     This configuration enables the splitting position of the tablet to be identified even when the surface without the splitting line is viewed by visual observation. Further, after a multi-dose packaging of tablets is carried out with a multi-dose packaging device, it is possible to inspect as to whether the tablet having the splitting line is contained in the multi-dose package by capturing an image of one surface. 
     The mark may be printed in a groove of the splitting line on the first surface. 
     This configuration enables the splitting position of the tablet to be clearly identified also on the surface with the splitting line. Further, it is possible to check the presence of a splitting line from either side of the tablet when using a multi-dose packaging device. 
     The mark may have a form that enables a determination as to abnormal splitting after the tablet is split. 
     This configuration enables a determination as to whether the tablet is split normally or abnormally after the tablet is split. Further, even when the split tablet is placed in a multi-dose package, it is possible to check whether or not the split tablet is split normally. 
     The mark having a form that enables a determination as to abnormal splitting after the tablet is split may include a straight line printed along a position corresponding to the splitting line in such a way as to cover both edges in a width direction of a groove of the splitting line. 
     According to this configuration, it is possible to determine by visual observation or with a multi-dose packaging device whether the tablet is split normally or abnormally since it is possible to determine that the tablet is split normally when the conditions that one edge in the width direction of the mark is continuous without break from one end to the other end of the tablet after the tablet is split and that the other edge in the width direction of the mark is not observed are confirmed. 
     Further, to solve the above-described problem, the present invention provides a tablet mark printing machine to print a mark at a splitting position of a tablet having a splitting line on a first surface and not having a splitting line on a second surface, the machine including: a recognition device to perform splitting line position recognition to recognize a position of the splitting line on the first surface of the tablet; and a second surface printing device to print the mark at a position corresponding to the position of the splitting line at least on the second surface. 
     This configuration enables the splitting position of the tablet to be identified even when the surface without the splitting line is viewed by visual observation. Further, after a multi-dose packaging of tablets is carried out with a multi-dose packaging device, it is possible to inspect as to whether the tablet having the splitting line is contained in the multi-dose package by capturing an image of one surface. 
     The tablet mark printing machine may further include a first surface printing device to print the mark in a groove of the splitting line on the first surface. 
     This configuration enables the splitting position of the tablet to be clearly identified also on the surface with the splitting line. Further, it is possible to check the presence of a splitting line from either side of the tablet when using a multi-dose packaging device. 
     The mark may have a form that enables a determination as to abnormal splitting after the tablet is split. 
     This configuration enables a determination as to whether the tablet is split normally or abnormally after the tablet is split. Further, even when the split tablet is placed in a multi-dose package, it is possible to check whether or not the split tablet is split normally. 
     The mark having a form that enables a determination as to abnormal splitting after the tablet is split may include a straight line printed along a position corresponding to the splitting line in such a way as to cover both edges in a width direction of a groove of the splitting line. 
     According to this configuration, it is possible to determine by visual observation or with a multi-dose packaging device whether the tablet is split normally or abnormally since it is possible to determine that the tablet is split normally when the conditions that one edge in the width direction of the mark is continuous without break from one end to the other end of the tablet after the tablet is split and that the other edge in the width direction of the mark is not observed are confirmed. 
     Further, to solve the above-described problem, the present invention provides a tablet having a splitting line on a first surface and not having a splitting line on a second surface, wherein a mark is printed at a position corresponding to the splitting line at least on the second surface. 
     This configuration enables the splitting position of the tablet to be identified even when the surface without the splitting line is viewed by visual observation. Further, after a multi-dose packaging of tablets is carried out with a multi-dose packaging device, it is possible to inspect as to whether the tablet having the splitting line is contained in the multi-dose package by capturing an image of one surface. 
     The mark may also be printed in a groove of the splitting line on the first surface. 
     This configuration enables the splitting position of the tablet to be clearly identified also on the surface with the splitting line. Further, it is possible to check the presence of a splitting line from either side of the tablet when using a multi-dose packaging device. 
     The mark may have a form that enables a determination as to abnormal splitting after the tablet is split. 
     This configuration enables a determination as to whether the tablet is split normally or abnormally after the tablet is split. Further, even when the split tablet is placed in a multi-dose package, it is possible to check whether or not the split tablet is split normally. 
     The mark having a form that enables a determination as to abnormal splitting after the tablet is split may include a straight line printed along a position corresponding to the splitting line in such a way as to cover both edges in a width direction of a groove of the splitting line. 
     According to this configuration, it is possible to determine by visual observation or with a multi-dose packaging device whether the tablet is split normally or abnormally since it is possible to determine that the tablet is split normally when the conditions that one edge in the width direction of the mark is continuous without break from one end to the other end of the tablet after the tablet is split and that the other edge in the width direction of the mark is not observed are confirmed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram for describing an example configuration of a tablet mark printing machine according to Embodiment 1 of the present invention. 
         FIG. 2  is a diagram for describing an example of a printing device portion of the tablet mark printing machine according to Embodiment 1 of the present invention. 
         FIG. 3  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 1 of the present invention. 
         FIG. 4  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 2 of the present invention. 
         FIG. 5  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 3 of the present invention. 
         FIG. 6  is a diagram for describing examples of split tablets with a mark printed thereon according to Embodiment 3 of the present invention. 
         FIG. 7  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 4 of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiment 1 
     Embodiment 1 of the present invention will be described below with reference to  FIGS. 1 to 3 .  FIG. 1  is a diagram for describing an example configuration of a tablet mark printing machine according to Embodiment 1 of the present invention.  FIG. 2  is a diagram for describing an example of a printing device portion of the tablet mark printing machine according to Embodiment 1 of the present invention.  FIG. 3  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 1 of the present invention. 
     As illustrated in  FIG. 1 , a tablet mark printing machine  100  according to Embodiment 1 of the present invention includes a disk  11 , a disk  12 , a disk  13 , a parts feeder  14 , a tablet feeding unit  15 , a printing device  21 , a printing device  31 , an image capturing device  41 , an image capturing device  51 , a storage box  17 , and the like. The disk  11  is arranged with the main surface thereof disposed vertically and the disk  12  is arranged vertically and perpendicularly to the disk  11  with the side surfaces of the disk  11  and the disk  12  close to each other. The disk  13  is arranged horizontally and perpendicularly to the disk  12  with the side surfaces of the disk  12  and the disk  13  close to each other. The disk  11 , the disk  12 , and the disk  13  have a plurality of suction holes on their circumferential side surfaces and are capable of drawing and holding tablets T by suction onto their suction holes. 
     It is assumed that a tablet according to the present invention has a splitting line on a first surface thereof and has no splitting line on a second surface thereof (see  FIG. 3  etc.). A splitting line is a groove defined on a surface of a tablet to make the tablet easier to split when the tablet is to be split. A tablet often has one groove called a splitting line defined in the form of a straight line from one end to the other end of the tablet to enable the tablet to be split in half as illustrated in  FIG. 3 , but a tablet may have two grooves perpendicular to each other in the form of a cross to enable the tablet to be split in quarters. Herein the circumferential side surface between the two main surfaces, i.e., the first surface and the second surface of the tablet T will be referred to as the side surface. 
     Next, an operation of the tablet mark printing machine  100  will be described. First, tablets T are fed from the tablet feeding unit  15  to the parts feeder  14 . The tablets T fed to the parts feeder  14  are gradually lined up in the horizontal direction by the vibration or rotation of the parts feeder  14 . At a final extremity of the parts feeder  14 , each of the tablets T so lined up is drawn by suction onto a nearby suction hole among the plurality of suction holes provided on the circumferential side surface of the disk  13 , the side surface of the tablet T being attached onto the suction hole. As the disk  13  rotates counterclockwise, the tablet T held by suction onto the suction hole on the circumferential side surface of the disk  13  is carried in a circular horizontal movement toward the disk  12 . When the tablet T comes close to the disk  12 , the suction from a suction hole of the disk  12  close to the tablet T is started while the suction from the suction hole of the disk  13  is halted and one of the main surfaces of the tablet T is drawn by suction onto the suction hole of the disk  12 . The disk  12  rotates clockwise to carry the tablet T held by suction thereon in a circular vertical movement toward the disk  11 . When the tablet T comes close to the disk  11 , the suction from a suction hole of the disk  11  close to the tablet T is started while the suction from the suction hole of the disk  12  is halted and the side surface of the tablet T is held by suction onto the suction hole of the disk  11 . As the disk  11  rotates, the tablet T held by suction onto the disk  11  is carried in a counterclockwise circular vertical movement. 
     Next, the splitting line position recognition of a tablet T held by suction onto the disk  11  and the printing of a mark on the tablet T will be described in detail with reference to  FIGS. 1 and 2 . The disk  11  receives from the disk  12  a vertically positioned tablet T at the initial extremity in the direction of rotation at the side of the disk  11  by drawing by suction the side surface of the tablet T and holds the tablet T by suction in a vertical posture. As the disk  11  rotates counterclockwise, the tablets T held by suction are consecutively carried in a counterclockwise circular movement. When a tablet T is brought by the circular movement to a position at which the image capturing device  41  and the image capturing device  51  can capture images, the tablet T is detected by a sensor (not illustrated) and the image capturing device  41  captures an image of one of the main surfaces of the tablet T and the image capturing device  51  captures an image of the other of the main surfaces of the tablet T. The image capturing device  41  and the image capturing device  51  are each constituted by a CMOS sensor and capture the images of the tablet T carried in a circular movement by using an electronic shutter and strobe to obtain images without blur. 
     The image capturing device  41  and the image capturing device  51  are both connected to a control device (not illustrated). The control device performs image processing on the images captured by the image capturing device  41  and the image capturing device  51 , determines whether a first surface with the splitting line is one of the main surfaces or the other of the main surfaces, and recognizes the position and the rotation angle of the splitting line on the first surface (to be referred to as “splitting line position recognition”). In other words, when the control device has determined that the splitting line is on one of the main surfaces, the image of which the image capturing device  41  captured, the control device determines that this one of the main surfaces is the first surface. When the control device has determined that the splitting line is on the other of the main surfaces, the image of which the image capturing device  51  captured, the control device determines that this other of the main surfaces is the first surface. The control device recognizes the position and the rotation angle of the splitting line on the surface that has been determined to be the first surface (splitting line position recognition). The position and the rotation angle of the splitting line can be recognized by image processing software. For example, a template matching technique or a boundary detection technique can be used for recognition. 
     Note that the position and the rotation angle of the splitting line is recognized in the splitting line position recognition in Embodiment 1 but, in a case in which the tablet T is supplied to the image capturing devices and the printing devices with the central position of the tablet T hardly out of alignment, the rotation angle may be recognized alone, the position of the splitting line not being recognized. 
     The tablet T for which the splitting line position recognition has been completed is conveyed in a circular movement to the position at which the printing device  21  and the printing device  31  can print a mark on the tablet T. The printing device  21  and the printing device  31  are each constituted by an inkjet printer and print a mark in a freely selected form by discharging ink from nozzles. In Embodiment 1, a mark M 1  is printed by a second surface printing device that faces the second surface, which has been determined to be without the splitting line. 
     Herein the second surface printing device means the printing device  21  or the printing device  31  that applies printing on the second surface of the tablet T, i.e., the surface without the splitting line. For example, in  FIG. 1  or  FIG. 2 , when the splitting line is on the surface facing the viewer, i.e., one of the main surfaces, the printing device  21  is the second surface printing device and when the splitting line is on the surface facing away from the viewer, i.e., the other of the main surfaces, the printing device  31  is the second surface printing device. 
     The printing device  21  and the printing device  31  are both connected to a control device (not illustrated). The control device performs control to execute printing by giving the print data that defines the form of the mark to the printing device that executes printing, i.e., the printing device  21  or the printing device  31 . 
     Thus, in Embodiment 1, at least a mark is printed at the position and the rotation angle corresponding to the position of the splitting line on the second surface. In other words, the position and the rotation angle on the second surface (i.e., the position corresponding to the position of the splitting line on the second surface) are calculated by reversing the position and the rotation angle of the splitting line on the first surface obtained by splitting line position recognition, and a solid straight line is printed as a mark at the position and the rotation angle from one end to the other end of the tablet. The mark may be printed in any color but a mark is easier to recognize when printed in a different color from that of the tablet surface.  FIG. 3  illustrates an example in which a solid straight line is printed on the second surface as a mark M 1 . 
     Note that, although a solid straight line is printed as mark M 1  in Embodiment 1, the form of the mark is not necessarily limited thereto and may be selected as appropriate in accordance with the requirements of the tablet. For example, a dashed or dotted straight line may be printed or a long dashed short dashed line may be printed. Further, characters such as the name of the medicine and the name of the company may be printed in addition to the mark M 1 . Further, the width of the mark M 1  may be freely selected and a mark width that makes the mark recognizable may be selected in accordance with the requirements of the tablet. The length of the mark M 1  may also be freely selected and the mark M 1  need not extend from one end to the other end of the tablet. 
     As the disk  11  rotates counterclockwise, the tablet T with the mark M 1  printed thereon is stored in the storage box  17  near the extremity in the direction of rotation of the disk  11 . 
     Note that, although no appearance inspection nor print inspection is performed on the tablet T in Embodiment 1, an appearance inspection may be performed to detect brakeage or chipping depending on the requirements of the tablet T, together with the splitting line position recognition. Further, a print inspection may be performed after the mark M 1  is printed. Further, a side surface appearance inspection may be performed by capturing an image of the side surface of the tablet T with an image capturing device while one of the main surfaces of the tablet T is held by suction onto the disk  12 . 
     As described above, in Embodiment 1, the splitting position of a tablet can be identified by visual observation or with a multi-dose packaging device even when the surface without the splitting line is viewed, owing to a tablet mark printing method of printing a mark on a splitting position of a tablet having a splitting line on a first surface and not having a splitting line on a second surface, the method including: performing splitting line position recognition to recognize a position of the splitting line on the first surface of the tablet; and printing the mark at a position corresponding to the position of the splitting line at least on the second surface. 
     Further, the splitting position of a tablet can be identified by visual observation or with a multi-dose packaging device even when the surface without the splitting line is viewed, owing to a tablet mark printing machine to print a mark at a splitting position of a tablet having a splitting line on a first surface and not having a splitting line on a second surface, the machine including: a recognition device to perform splitting line position recognition to recognize a position of the splitting line on the first surface of the tablet; and a second surface printing device to print the mark at a position corresponding to the position of the splitting line at least on the second surface. 
     Further, the splitting position of a tablet can be identified by visual observation or with a multi-dose packaging device even when the surface without the splitting line is viewed, owing to a tablet having a splitting line on a first surface and not having a splitting line on a second surface, wherein a mark is printed at a position corresponding to the splitting line at least on the second surface. 
     Embodiment 2 
     Embodiment 2 of the present invention differs from Embodiment 1 in that a mark is also printed in the groove of the splitting line on the first surface in addition to the second surface of the tablet. Embodiment 2 will be described below with reference to  FIG. 4 .  FIG. 4  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 2 of the present invention. 
     As in Embodiment 1, when a tablet T is brought by the disk  11  in a circular movement to a position at which the image capturing device  41  and the image capturing device  51  can capture images, the tablet T is detected by a sensor (not illustrated) and the image capturing device  41  captures an image of one of the main surfaces of the tablet T and the image capturing device  51  captures an image of the other of the main surfaces of the tablet T. A control device (not illustrated) performs image processing on the images captured by the image capturing device  41  and the image capturing device  51 , determines whether a first surface with the splitting line is one of the main surfaces or the other of the main surfaces, and recognizes the position and the rotation angle of the splitting line on the first surface (to be referred to as “splitting line position recognition”). In other words, when the control device has determined that the splitting line is on one of the main surfaces, the image of which the image capturing device  41  captured, the control device determines that this one of the main surfaces is the first surface. When the control device has determined that the splitting line is on the other of the main surfaces, the image of which the image capturing device  51  captured, the control device determines that this other of the main surfaces is the first surface. The control device recognizes the position and the rotation angle of the splitting line on the surface that has been determined to be the first surface (splitting line position recognition). 
     The tablet T for which the splitting line position recognition has been completed is conveyed in a circular movement to the position at which the printing device  21  and the printing device  31  can print a mark on the tablet T. The printing device  21  and the printing device  31  are each constituted by an inkjet printer and print a mark in a freely selected form by discharging ink from nozzles. In Embodiment 2, a mark M 2 , which is a solid straight line, is printed in the groove of the splitting line from one end to the other end of the tablet by a first surface printing device facing the first surface with the splitting line, in addition to the mark M 1  printed by the second surface printing device facing the second surface (see  FIG. 4 ). 
     Note that, although a solid straight line is printed as mark M 2  in Embodiment 2, the form of the mark is not necessarily limited thereto and may be selected as appropriate in accordance with the requirements of the tablet. For example, a dashed or dotted straight line may be printed or a long dashed short dashed line may be printed. Further, characters such as the name of the medicine and the name of the company may be printed in addition to the mark M 2 . Further, the width of the mark M 1  may be freely selected and a mark width that makes the mark recognizable may be selected in accordance with the requirements of the tablet. The length of the mark M 1  may also be freely selected and the mark M 1  need not extend from one end to the other end of the tablet. Further, the mark M 1  on the second surface and the mark M 2  on the first surface may be marks in different forms. 
     Thus, in Embodiment 2, since a mark is also printed in the groove of the splitting line on the first surface as well as on the second surface of the tablet, the splitting position of the tablet can be clearly identified by visual observation or with a multi-dose packaging device also on the surface with the splitting line. 
     Embodiment 3 
     Embodiment 3 of the present invention differs from Embodiment 1 or Embodiment 2 in that the mark printed on a tablet has a form that enables a determination as to abnormal splitting after the tablet is split. Embodiment 3 will be described below with reference to  FIGS. 5 and 6 .  FIG. 5  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 3 of the present invention.  FIG. 6 ( a )  is a diagram for describing an example of a normal splitting of a tablet with a mark printed thereon according to Embodiment 3 of the present invention.  FIG. 6 ( b )  is a diagram for describing an example of an abnormal splitting of a tablet with a mark printed thereon according to Embodiment 3 of the present invention.  FIG. 6 ( c )  is a diagram for describing another example of an abnormal splitting of a tablet with a mark printed thereon according to Embodiment 3 of the present invention. 
     That the mark printed on a tablet has a form that enables a determination as to abnormal splitting after the tablet is split means that it is possible to determine whether the tablet is split normally or abnormally by looking at the mark after the tablet is split.  FIG. 5  illustrates an example of a mark having a form that enables a determination as to abnormal splitting after the tablet is split. The mark M 3  illustrated in  FIG. 5  is an example of printing a straight line along the position corresponding to the splitting line on the second surface in such a way as to cover both edges in the width direction of the groove of the splitting line and the mark M 4  is an example of printing a straight line along the position corresponding to the splitting line on the first surface in such a way as to cover both edges in the width direction of the groove of the splitting line. The mark M 3  and the mark M 4  are straight lines printed along the positions corresponding to the splitting line in such a way as to at least cover both edges in the width direction of the groove of the splitting line. 
     Herein, on the first surface, a straight line printed along the splitting line in such a way as to cover the positions corresponding to both edges in the width direction of the groove of the splitting line may be a straight line printed along the splitting line and covering both edges in the width direction defining the groove of the splitting line and may be a straight line that includes some positions out of the groove. Further, on the second surface, the line may be a straight line printed at the position and the rotation angle corresponding to the splitting line and having a width covering both edges in the width direction defining the groove of the splitting line on the first surface and may be somewhat wider. Further, the straight lines of the mark M 3  and the mark M 4  in Embodiment 3 are solid lines but the lines are not necessarily limited thereto and may be broken lines, dotted lines, or long dashed short dashed lines. Further, the mark M 3  and the mark M 4  may be marks in different forms from each other. 
       FIG. 6  illustrates examples of a split tablet T with the mark M 3  and the mark M 4  illustrated in  FIG. 5  printed thereon.  FIG. 6 ( a )  illustrates an example of a normal splitting. In other words, in a normal splitting, it is observed that one edge in the width direction of the mark M 3  or the mark M 4  is continuous without break from one end to the other end of the tablet T and the other edge in the width direction of the mark M 3  or the mark M 4  is not observed. In contrast, in an abnormal splitting, it is observed that one edge in the width direction of the mark M 3  or the mark M 4  is continuous without break from one end to the other end of the tablet T and at least part of the other edge in the width direction of the mark M 3  or the mark M 4  is observed ( FIG. 6 ( b ) ). In another example, it is not observed that one edge in the width direction of the mark M 3  or the mark M 4  is continuous without break from one end to the other end of the tablet T (part of the edge is missing) ( FIG. 6  ( c )). 
     In other words, it is possible to determine that the tablet is split normally when the conditions that one edge in the width direction of the mark M 3  or the mark M 4  is continuous without break from one end to the other end of the tablet T and that the other edge in the width direction of the mark M 3  or the mark M 4  is not observed are confirmed. It is possible to determine that the tablet is split abnormally when not all the conditions are confirmed. 
     Note that, although the first surface has a mark M 4  printed thereon and the second surface has a mark M 3  printed thereon in Embodiment 3, the configuration is not necessarily limited thereto and the first surface may have no mark, with only the second surface having a mark M 3  printed thereon. 
     Thus, in Embodiment 3, it is possible to determine by visual observation or with a multi-dose packaging device whether the tablet is split normally or abnormally after the tablet is split. 
     Embodiment 4 
     Embodiment 4 of the present invention differs from Embodiment 3 in that the mark includes two straight lines printed along the splitting line in such a way as to cover the positions corresponding to both edges in the width direction of the groove of the splitting line. Embodiment 4 will be described below with reference to  FIG. 7 .  FIG. 7  is a diagram for describing an example of a tablet with a mark printed thereon according to Embodiment 4 of the present invention. 
     In Embodiment 4, as illustrated in  FIG. 7 , the mark M 5  on the second surface of the tablet T includes two straight lines printed from one end to the other end of the tablet T at the position and the rotation angle corresponding to the splitting line in such a way as to cover both edges in the width direction defining the groove of the splitting line on the first surface, the straight lines consisting of one straight line at a position corresponding to one edge in the width direction of the groove and the other straight line at a position corresponding to the other edge. Further, the mark M 6  includes two straight lines printed along the splitting line in such a way as to cover the edges in the width direction defining the groove of the splitting line, the straight lines consisting of one straight line at a position corresponding to one edge in the width direction of the groove and the other straight line at a position corresponding to the other edge. In other words, no mark is printed at a position corresponding to the central portion in the width direction of the groove. 
     Herein, the mark M 5  or the mark M 6  may be a straight line and may be a dashed line, a dotted straight line, or a long dashed short dashed line. Further, although the first surface has a mark M 6  printed thereon and the second surface has a mark M 5  printed thereon in Embodiment 4, the configuration is not necessarily limited thereto and the first surface may have no mark, with only the second surface having a mark M 5  printed thereon. Further, the mark M 6  and the mark M 5  may be marks in different forms from each other. 
     The M 5  or the M 6  in Embodiment 4 also has a form that enables a determination as to abnormal splitting after the tablet is split. In other words, in a normal splitting, it is observed that one edge in the width direction of the mark M 5  or the mark M 6  is continuous without break from one end to the other end of the tablet T and the other edge in the width direction of the mark M 5  or the mark M 6  is not observed. Further, in an abnormal splitting, it is observed that one edge in the width direction of the mark M 5  or the mark M 6  is continuous without break from one end to the other end of the tablet T and at least part of the other edge in the width direction of the mark M 5  or the mark M 6  is observed. In another example, it is not observed that one edge in the width direction of the mark M 5  or the mark M 6  is continuous without break from one end to the other end of the tablet T (part of the edge is missing). 
     In other words, it is possible to determine that the tablet is split normally when the conditions that one edge in the width direction of the mark M 5  or the mark M 6  is continuous without break from one end to the other end of the tablet T and that the other edge in the width direction of the mark M 5  or the mark M 6  is not observed are confirmed. It is possible to determine that the tablet is split abnormally when not all the conditions are confirmed. 
     Thus, in Embodiment 4, it is possible to save the ink as no mark is printed on the middle portion in the direction of the groove since the mark includes two straight lines printed along the splitting line in such a way as to cover the positions corresponding to both edges in the width direction of the groove of the splitting line, the straight lines consisting of one straight line at a position corresponding to one edge in the width direction of the groove and the other straight line at a position corresponding to the other edge, and further, it is possible to determine by visual observation or with a multi-dose packaging device whether the tablet is split normally or abnormally after the tablet is split since the mark has a form that enables a determination as to abnormal splitting after the tablet is split. 
     INDUSTRIAL APPLICABILITY 
     A tablet mark printing method, a tablet mark printing machine, and a tablet according to the present invention can be applied widely in areas in which it is necessary to split a tablet. 
     REFERENCE SIGNS LIST 
     
         
           11  disk 
           12  disk 
           13  disk 
           14  parts feeder 
           15  tablet feeding unit 
           17  storage box 
           21  printing device 
           31  printing device 
           41  image capturing device 
           51  image capturing device 
         M 1  to M 6  mark 
         T tablet