Tablet Printing Equipment

Abstract

To provide a technique that can inhibit an ink from peeling from tablets after discharge of ink droplets even in a case that the ink droplets are discharged to tablets, such as film coating tablets and sugar coating tables, which have high liquid repellency on its surface and into which a liquid does not penetrate easily.SOLUTION: A tablet printer 1 is a device which prints images on surfaces of tablets 9, and includes a first printing part 40, a first preheating part, a second printing part 50 and a second preheating part. The first printing part 40 prints an image on one surface of a tablet 9 conveyed by a first transport conveyor 41. The first preheating part heats the tablet 9 on the upstream side of a conveyance path with respect to the first printing part 40. The second printing part 50 prints an image on the other surface of the tablet 9 delivered from the first transport conveyor 41 and conveyed by a second transport conveyor 51. The second preheating part heats the tablet 9 on the downstream side of the conveyance path with respect to the first printing part 40 and on the upstream side of the conveyance path with respect to the second printing part 50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printing device that prints images on tablets using an inkjet method. [Background technology]

[0002] On tablets, which are pharmaceutical products, letters and codes are printed to identify the product. Although such letters and codes may be recorded by engraving, there is a problem that the visibility of engraving is low. In particular, in recent years, the types of tablets have become more diverse due to the spread of generic drugs. For this reason, it is required to print clearly on the surface of the tablet so that the tablet can be identified reliably. In addition, since tablets are sensitive to pressure, it is preferable to apply a small pressure to the tablet when printing. Due to these circumstances, a technology for printing images on tablets using an inkjet method has been attracting attention in recent years.

[0003] Conventional printing devices that print images on tablets using an inkjet method are described in, for example, Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-143539 [Patent Document 2] JP 2017-534 A Summary of the Invention [Problem to be solved by the invention]

[0005] The solid preparation printing device of Patent Document 1 has a heater, a hot air dryer, or the like (180) for thoroughly drying the ink transferred to the solid preparation (200) before the solid preparation (200) is collected. Also, the tablet printing device (1) of Patent Document 2 has a heater that supplies radiant heat or a blower that supplies warm or hot air for drying the ink applied to the tablet (T).

[0006] However, for example, in the case of tablets with a highly liquid-repellent surface, such as film-coated tablets (FC tablets) or sugar-coated tablets, which are difficult for liquid to penetrate, when the surface tension of the ink applied to the tablet is high, or when the ink is difficult to dry, there is a risk of the ink flowing over the tablet surface to minimize the surface area (bulge phenomenon) after the ink is applied to the tablet. In this case, even if the tablet is subsequently dried and further coated, the ink is unlikely to adhere to the tablet, and there is a risk of the ink peeling off from the tablet due to slight contact such as rubbing.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a technology that can prevent ink from peeling off from a tablet after ejecting ink droplets onto the tablet, such as a film-coated tablet (FC tablet) or a sugar-coated tablet, which has a highly liquid-repellent surface and is difficult for liquid to penetrate. [Means for solving the problem]

[0008] In order to solve the above problems, the first invention of the present application is a tablet printing device that prints an image on a surface of a tablet, comprising a first transport conveyor, a first printing unit, a first preheating unit, a second transport conveyor, a second printing unit, and a second preheating unit. With a table, The first conveyor conveys the tablet while holding the other side thereof. The first printing unit prints an image on one side of the tablet conveyed by the first conveyor. The first preheating unit heats the tablet on the upstream side of the conveying path from the first printing unit. The second conveyor conveys the tablet while holding the one side of the tablet handed over from the first conveyor. The second printing unit prints an image on the other side of the tablet conveyed by the second conveyor. The second preheating unit heats the tablet on the downstream side of the conveying path from the first printing unit and upstream of the conveying path from the second printing unit. The table conveys the tablet placed on the upper surface by its own rotation. The tablet placed on the upper surface of the table moves relative to the first preheating unit in accordance with the rotation of the table and is heated by the first preheating unit.

[0009] A second invention of the present application is the tablet printing device of the first invention, wherein the first preheating section or the second preheating section heats the tablets by supplying warm air or hot air toward the tablets.

[0010] A third invention of the present application is the tablet printing apparatus of the first invention, wherein the first preheating section or the second preheating section heats the tablets by radiating far infrared rays toward the tablets.

[0011] A fourth invention of the present application is the tablet printing apparatus of the second invention, wherein the temperature of the warm air or hot air is 40°C or higher and 140°C or lower.

[0012] The fifth invention of the present application is a tablet printing device of any one of the first to fourth inventions, wherein the first printing unit and the second printing unit print an image by ejecting ink droplets onto the surface of a tablet, and the ejected ink droplets are droplets of pigment ink. Effect of the Invention

[0013] According to the first to fifth aspects of the present application, the ink droplets are ejected onto the surface of the tablet after the tablet is heated, thereby improving the fixation of the ink on the surface of the tablet, which in turn prevents the ink from peeling off from the tablet.

[0014] In particular, according to the second or fourth invention of the present application, it is easy to heat a plurality of tablets uniformly. In addition, it is easy to prevent the tablets from being overheated. Furthermore, it is possible to heat the tablets without significantly changing the configuration of a conventional tablet printing device. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram showing a configuration of a tablet printing device. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 2 is a block diagram showing connections between a control unit and each unit in the tablet printing device. FIG. [Diagram 5] FIG. 4 is a block diagram conceptually illustrating a portion of the functions of a control unit. [Figure 6] FIG. 2 is a top view of a plurality of tablets transported by a first transport conveyor. [Figure 7] FIG. 11 is a diagram showing an example of a print image. [Figure 8] FIG. 13 is a diagram showing the results of verifying the effect of heating an enteric film-coated tablet before ejecting ink droplets onto the tablet. [Figure 9] 13A and 13B are diagrams showing the results of verifying the effect of heating a sugar-coated tablet before ejecting ink droplets onto the tablet. [Figure 10] FIG. 13 shows the results of verifying the effect of heating a tablet before ejecting ink droplets onto the tablet, which is an uncoated tablet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the direction in which a plurality of tablets are transported is referred to as the "transport direction", and the direction perpendicular and horizontal to the transport direction is referred to as the "width direction".

[0017] <1. Configuration of tablet printing device> The configuration of a tablet printing device 1 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of a tablet printing device 1 according to one embodiment of the present invention. The tablet printing device 1 of this embodiment is a device that conveys a plurality of tablets 9 and prints images such as a product name, product code, company name, and logo mark on the surface of each tablet 9 by an inkjet method.

[0018] For example, the tablet 9 of this embodiment is an enteric film-coated tablet (enteric FC tablet) with high liquid repellency, which is coated on the surface. However, the tablet 9 may be a sugar-coated tablet, or an uncoated tablet such as an orally disintegrating tablet (OD tablet) or a plain tablet (plain tablet). The tablet 9 may be a capsule, including a hard capsule and a soft capsule. The "tablet" in the present invention is not limited to a tablet as a medicine, but may also be a tablet as a health food or a tablet candy such as Ramune. The tablet 9 of this embodiment has a three-dimensional shape of a flattened sphere, for example, as shown in Figs. 8 to 10 described later. However, the shape of the tablet 9 is not limited to this.

[0019] 1, the tablet printing apparatus 1 of this embodiment has a hopper 10, a feeder unit 20, a preheat unit 25, a transport drum 30, a first printing unit 40, a second printing unit 50, an output conveyor 60, and a control unit 70. The hopper 10, the feeder unit 20, the transport drum 30, the first transport conveyor 41 of the first printing unit 40, the second transport conveyor 51 of the second printing unit 50, and the output conveyor 60 form a transport mechanism that transports the tablets 9 along a predetermined transport path.

[0020] The hopper 10 is an input section for receiving a large number of tablets 9 into the device all at once. The hopper 10 is disposed at the top of the housing 100 of the tablet printing device 1. The hopper 10 has an opening 11 located on the upper surface of the housing 100 and a funnel-shaped inclined surface 12 that gradually converges downward. The multiple tablets 9 (enteric film-coated tablets) input into the opening 11 flow into the linear feeder 21 along the inclined surface 12.

[0021] The feeder unit 20 is a mechanism for transporting a plurality of tablets 9 fed into the hopper 10 to the transport drum 30. The feeder unit 20 of this embodiment has a linear feeder 21, a rotary feeder 22, and a supply feeder 23. The linear feeder 21 has a flat plate-shaped vibrating trough 211. The plurality of tablets 9 fed from the hopper 10 to the vibrating trough 211 are transported to the rotary feeder 22 side by the vibration of the vibrating trough 211. The rotary feeder 22 has a disk-shaped rotating table 221. The plurality of tablets 9 dropped from the vibrating trough 211 onto the upper surface of the rotating table 221 are collected near the outer periphery of the rotating table 221 by the centrifugal force caused by the rotation of the rotating table 221.

[0022] The supply feeder 23 has a plurality of cylindrical parts 231 extending vertically downward from the outer periphery of the rotating table 221 to the conveying drum 30. FIG. 2 is a perspective view of the vicinity of the conveying drum 30. As shown in FIG. 2, a plurality of cylindrical parts 231 (eight in the example of FIG. 2) are arranged parallel to each other. The plurality of tablets 9 conveyed to the outer periphery of the rotating table 221 are each supplied to one of the plurality of cylindrical parts 231 and fall inside the cylindrical part 231. Then, the plurality of tablets 9 are stacked in each cylindrical part 231. In this way, the plurality of tablets 9 are aligned in a plurality of conveying rows by being distributed and supplied to the plurality of cylindrical parts 231. Then, the plurality of tablets 9 in each conveying row are supplied to the conveying drum 30 in order from the one at the bottom.

[0023] A preheating unit 25 is provided above the rotary feeder 22. The preheating unit 25 is fixed to the housing 100 of the tablet printing device 1. The preheating unit 25 is a mechanism for heating the tablets 9 by, for example, supplying warm or hot air toward the tablets 9 conveyed on the upper surface of the rotary table 221. The tablets 9 are heated by the warm or hot air from the preheating unit 25 for several seconds to several minutes in the process of being conveyed on the upper surface of the rotary table 221. This allows the plurality of tablets 9 to be heated almost uniformly. In addition, the temperature of the warm or hot air supplied from the preheating unit 25 toward the tablets 9 is, for example, 40° C. or higher and 140° C. or lower. This allows the tablets 9 to be prevented from being overheated. In addition, for example, a commercially available heater or dryer is used for the preheating unit 25. However, for example, a device (for example, a heater, etc.) that heats the tablets 9 by emitting far infrared rays may be used for the preheating unit 25. With this configuration, the tablet 9 can be heated upstream of the conveying path from the point where ink droplets are ejected onto the tablet 9 (the first head 431 and the second head 531 described below) without significantly modifying the configuration of a conventional tablet printing device.

[0024] The tablets 9 heated by the preheating unit 25 reach the first printing unit 40 and the second printing unit 50 through the supply feeder 23 and the conveying drum 30. As described above, the preheating unit 25 in this embodiment is disposed at a position away from the first head 431 and the second head 531, which will be described later, that eject ink droplets onto the tablets 9. This makes it possible to prevent the heat from the preheating unit 25 from adversely affecting the first head 431 and the second head 531. However, the position at which the preheating unit 25 is provided may be any position upstream of the conveying path from the first head unit 43, which will be described later, of the first printing unit 40, and is not limited to the position above the rotary feeder 22 as in this embodiment. The effect of heating the tablets 9 before ink droplets are ejected onto the surfaces of the tablets 9 by the preheating unit 25 will be described in detail later.

[0025] The conveying drum 30 is a mechanism for transferring a plurality of tablets 9 from the supply feeder 23 to the first conveyor 41. The conveying drum 30 has an outer peripheral surface of a substantially cylindrical shape. The conveying drum 30 rotates in the direction of the arrow in FIG. 1 and FIG. 2 about a rotation axis extending in the width direction by power obtained from a motor (not shown). As shown in FIG. 2, a plurality of holding portions 31 are provided on the outer peripheral surface of the conveying drum 30. The holding portion 31 is a recess that is recessed inward from the outer peripheral surface of the conveying drum 30. The plurality of holding portions 31 are arranged along the circumferential direction on the outer peripheral surface of the conveying drum 30 at width-direction positions corresponding to each of the plurality of conveying rows described above. In addition, a suction hole 32 is provided at the bottom of each holding portion 31.

[0026] A suction mechanism (not shown) is provided inside the conveying drum 30. When the suction mechanism is operated, a negative pressure lower than atmospheric pressure is generated in each of the plurality of suction holes 32. The holding section 31 suctions and holds the tablets 9 supplied from the supply feeder 23 one by one by the negative pressure. In addition, a blow mechanism (not shown) is provided inside the conveying drum 30. The blow mechanism blows locally pressurized gas from the inside of the conveying drum 30 toward the first conveyor 41 side described later. As a result, in the holding section 31 not facing the first conveyor 41, the suction state of the tablets 9 is maintained, while only in the holding section 31 facing the first conveyor 41, the suction of the tablets 9 is released. In this way, the conveying drum 30 rotates while suctioning and holding the plurality of tablets 9 supplied from the supply feeder 23, and can transfer the tablets 9 to the first conveyor 41.

[0027] A first state detection camera 33 is provided at a position facing the outer circumferential surface of the conveying drum 30. The first state detection camera 33 is an imaging unit that captures an image of the state of the tablets 9 held on the conveying drum 30. The first state detection camera 33 captures an image of the tablets 9 conveyed by the conveying drum 30, and transmits the obtained image to the control unit 70. Based on the received image, the control unit 70 detects the presence or absence of tablets 9 in each holding unit 31, the front and back sides, and the rotation angle of the tablets 9 held in the holding units 31.

[0028] The first printing unit 40 is a processing unit for printing an image on one side of the tablet 9. As shown in FIG. 1, the first printing unit 40 has a first transport conveyor 41, a second state detection camera 42, a first head unit 43, a first inspection camera 44, and a first afterheat unit 45.

[0029] The first transport conveyor 41 has a pair of first pulleys 411 and a circular first transport belt 412 stretched between the pair of first pulleys 411. The first transport belt 412 is disposed so that a portion thereof faces closely the outer circumferential surface of the transport drum 30. One of the pair of first pulleys 411 rotates by power obtained from a motor (not shown). As a result, the first transport belt 412 rotates in the direction of the arrow in FIGS. 1 and 2. At this time, the other of the pair of first pulleys 411 rotates in accordance with the rotation of the first transport belt 412.

[0030] 2, the first conveyor belt 412 is provided with a plurality of holding portions 413. The holding portions 413 are recesses recessed inward from the outer surface of the first conveyor belt 412. The holding portions 413 are arranged in the conveying direction at widthwise positions corresponding to the plurality of conveying rows. That is, the holding portions 413 are arranged at intervals in the widthwise direction and the conveying direction. The widthwise interval of the holding portions 413 on the first conveyor belt 412 is equal to the widthwise interval of the holding portions 31 on the conveyor drum 30.

[0031] The bottom of each holding section 413 is provided with a suction hole 414. The first conveyor 41 also has a suction mechanism (not shown) inside the first conveyor belt 412. When the suction mechanism is operated, a negative pressure lower than atmospheric pressure is generated in each of the plurality of suction holes 414. The holding section 413 suctions and holds the tablets 9 delivered from the conveyor drum 30 one by one by the negative pressure. As a result, the first conveyor 41 conveys the plurality of tablets 9 while holding them in a state aligned in a plurality of conveyor rows spaced apart in the width direction. Furthermore, the first conveyor belt 412 is provided with a blow mechanism (not shown). When the blow mechanism is operated, the suction hole 414 in the holding section 413 facing the second conveyor 51 described later becomes a positive pressure higher than atmospheric pressure. As a result, the suction of the tablets 9 in the holding section 413 is released, and the tablets 9 are delivered from the first conveyor 41 to the second conveyor 51. When the tablet 9 is transferred from the first transport conveyor 41 to the second transport conveyor 51, the tablet 9 is turned upside down.

[0032] The second status detection camera 42 is an imaging unit that captures images of the status of the tablet 9 held on the first transport conveyor 41, upstream of the first head unit 43 in the transport direction. The first status detection camera 33 and the second status detection camera 42 capture images of opposite sides of the tablet 9. The images obtained by the second status detection camera 42 are transmitted from the second status detection camera 42 to the control unit 70. Based on the received images, the control unit 70 detects the presence or absence of the tablet 9 in each holding unit 413, the front and back sides, and the rotation angle of the tablet 9 held in the holding unit 413.

[0033] The first head unit 43 is an inkjet head unit that ejects ink droplets toward the surface of the tablet 9 transported by the first transport conveyor 41. The first head unit 43 has four first heads 431 arranged along the transport direction. The four first heads 431 eject ink droplets of different colors (for example, cyan, magenta, yellow, and black) toward the surface of the tablet 9. A multi-color image is printed on the surface of the tablet 9 by superimposing monochromatic images formed by these colors. Note that, for the ink ejected from each first head 431, edible ink manufactured from raw materials approved by the Japanese Pharmacopoeia, Food Sanitation Law, etc. is used. In addition, in this embodiment, the ink droplets ejected from the first head 431 and the second head 531 described later are droplets of water-insoluble pigment ink. However, the ink droplets ejected from the first head 431 and the second head 531 described later may be droplets of water-soluble dye ink.

[0034] FIG. 3 is a bottom view of one first head 431. In FIG. 3, the first conveyor belt 412 and the plurality of tablets 9 held by the first conveyor belt 412 are indicated by two-dot chain lines. As shown enlarged in FIG. 3, the bottom surface of the first head 431 is provided with a plurality of nozzles 430 capable of ejecting ink droplets. In this embodiment, the plurality of nozzles 430 are two-dimensionally arranged in the conveying direction and the width direction on the bottom surface of the first head 431. Each nozzle 430 is arranged with its position shifted in the width direction. In this way, if the plurality of nozzles 430 are arranged two-dimensionally, the positions of the nozzles 430 in the width direction can be brought close to each other. However, the plurality of nozzles 430 may be arranged in a line along the width direction.

[0035] The method of ejecting ink droplets from the nozzle 430 uses, for example, a so-called piezo method in which a voltage is applied to a piezo element to deform it, thereby pressurizing and ejecting the ink in the nozzle 430. However, the method of ejecting ink droplets may also be a so-called thermal method in which electricity is passed through a heater to heat and expand the ink in the nozzle 430, thereby ejecting the ink.

[0036] Returning to FIG. 1, the first inspection camera 44 is an imaging unit for checking the printing result by the first head unit 43. The first inspection camera 44 captures an image of the tablet 9 being transported on the first transport belt 412 downstream of the first head unit 43 in the transport direction. The first inspection camera 44 also transmits the obtained image to the control unit 70. Based on the received image, the control unit 70 inspects whether the image printed on the surface of each tablet 9 has any printing defects such as misalignment or missing dots.

[0037] The first afterheating section 45 is a mechanism for heating the tablet 9 being transported downstream of the first head 431 in the transport path. For example, a hot air drying type heater that blows hot air toward the tablet 9 being transported by the first transport conveyor 41 is used in the first afterheating section 45. When the tablet 9 passes near the first afterheating section 45, the ink ejected onto the surface of the tablet 9 by the first head unit 43 is dried by the hot air and fixed on the surface of the tablet 9. In this embodiment, the first afterheating section 45 is disposed downstream of the first inspection camera 44 in the transport direction. However, the first afterheating section 45 may be disposed between the first head unit 43 and the first inspection camera 44.

[0038] The second printing unit 50 is a processing unit for printing an image on the other side of the tablet 9 after printing by the first printing unit 40. As shown in FIG. 1, the second printing unit 50 has a second conveyor 51, a third state detection camera 52, a second head unit 53, a second inspection camera 54, a second afterheat unit 55, and a defective product recovery unit 56. The second conveyor 51 holds and conveys the plurality of tablets 9 delivered from the first conveyor 41. The third state detection camera 52 photographs the plurality of tablets 9 conveyed by the second conveyor 51 on the upstream side of the conveying direction from the second head unit 53. The second head unit 53 ejects ink droplets toward the surface of the tablet 9 conveyed by the second conveyor 51. The second inspection camera 54 photographs the plurality of tablets 9 conveyed by the second conveyor 51 on the downstream side of the conveying direction from the second head unit 53. The second afterheat section 55 heats the tablet 9 being transported downstream of the transport path from the second head 531. As a result, the ink ejected onto the surface of the tablet 9 by the second head unit 53 is dried by the hot air and fixed on the surface of the tablet 9.

[0039] Details of the second transport conveyor 51, the third condition detection camera 52, the second head unit 53, the second inspection camera 54, and the second after-heat section 55 are the same as those of the first transport conveyor 41, the second condition detection camera 42, the first head unit 43, the first inspection camera 44, and the first after-heat section 45 described above, so duplicate explanations will be omitted.

[0040] The defective product collecting section 56 collects tablets 9 determined to be defective based on the captured images obtained from the above-mentioned five cameras 33, 42, 44, 52, and 54. The defective product collecting section 56 has a blow mechanism (not shown) arranged inside the second transport conveyor 51, and a collection box 561. When a tablet 9 determined to be defective is transported to the defective product collecting section 56, the blow mechanism blows pressurized gas from the inside of the second transport conveyor 51 toward the tablet 9. As a result, the tablet 9 falls off the second transport conveyor 51 and is collected in the collection box 561.

[0041] The discharge conveyor 60 is a mechanism for discharging a plurality of tablets 9 determined to be non-defective to the outside of the housing 100 of the tablet printing device 1. The upstream end of the discharge conveyor 60 is located below the second pulley 511 of the second transport conveyor 51. The downstream end of the discharge conveyor 60 is located outside the housing 100. For example, a belt transport mechanism is used for the discharge conveyor 60. The plurality of tablets 9 that have passed through the defective product recovery section 56 drop from the second transport conveyor 51 to the upper surface of the discharge conveyor 60 by releasing the suction of the suction holes. Then, the plurality of tablets 9 are discharged to the outside of the housing 100 by the discharge conveyor 60.

[0042] The control unit 70 is a means for controlling the operation of each unit in the tablet printing apparatus 1. FIG. 4 is a block diagram showing the connection between the control unit 70 and each unit in the tablet printing apparatus 1. As conceptually shown in FIG. 4, the control unit 70 is composed of a computer having a processor 701 such as a CPU, a memory 702 such as a RAM, and a storage device 703 such as a hard disk drive. A computer program P and data D for executing the printing process and the inspection process are stored in the storage device 703.

[0043] As shown in FIG. 4, the control unit 70 is communicatively connected to each of the above-mentioned straight feeder 21, rotary feeder 22, preheating section 25, conveying drum 30 (including a motor, suction mechanism, and blowing mechanism), first status detection camera 33, first conveyor 41 (including a motor, suction mechanism, and blowing mechanism), second status detection camera 42, first head unit 43 (including multiple nozzles 430 of each first head 431), first inspection camera 44, first afterheating section 45, second conveyor 51, third status detection camera 52, second head unit 53 (including multiple nozzles 430 of each second head 531), second inspection camera 54, second afterheating section 55, defective product recovery section 56, and discharge conveyor 60.

[0044] The control unit 70 temporarily reads out the computer program P and data D stored in the storage device 703 into the memory 702, and the processor 701 performs arithmetic processing based on the computer program P, thereby controlling the operation of each of the above-mentioned units. This allows the printing process for the multiple tablets 9 to proceed.

[0045] <2. Data processing in the control unit> Fig. 5 is a block diagram conceptually showing some of the functions of the control unit 70. As shown in Fig. 5, the control unit 70 of this embodiment has an angle recognition unit 71, a head control unit 72, and an inspection unit 73. The functions of these units are realized by temporarily reading out a computer program P and data D stored in a storage device 703 of the control unit 70 into a memory 702, and having a processor 701 perform arithmetic processing based on the computer program P.

[0046] The angle recognition unit 71 is a function for recognizing the rotation angle of each tablet 9 being transported. The angle recognition unit 71 acquires images captured by the first status detection camera 33 and the second status detection camera 42, and recognizes the rotation angle of each tablet 9 transported by the first transport conveyor 41 based on the captured images. The angle recognition unit 71 also acquires images captured by the third status detection camera 52, and recognizes the rotation angle of each tablet 9 transported by the second transport conveyor 51 based on the captured images.

[0047] FIG. 6 is a top view of a plurality of tablets 9 conveyed by the first conveyor 41. In the example of FIG. 6, scored tablets having a score line 91 are conveyed as the tablets 9. For such scored tablets, printing must be performed at a rotation angle according to the orientation of the score line 91. For this reason, the angle recognition unit 71 recognizes the rotation angle (the orientation of the score line 91) for each tablet 9 when it passes through the first head unit 43 based on the captured images obtained from the first state detection camera 33 and the second state detection camera 42. Similarly, the angle recognition unit 71 recognizes the rotation angle (the orientation of the score line 91) for each tablet 9 when it passes through the second head unit 53 based on the captured images obtained from the third state detection camera 52.

[0048] In addition, the tablet 9 of this embodiment has a dividing line 91 only on the first surface out of the first and second surfaces, which are the front and back surfaces. In addition, the front and back surfaces of the multiple tablets 9 to be conveyed are not constant. For this reason, as shown in FIG. 6, tablets 9 held with the first surface facing upward and tablets 9 held with the second surface facing upward may be conveyed in a mixed state. In such a case, the angle recognition unit 71 may recognize the rotation angle when passing through the first head unit 43 for some tablets 9 based on the captured image obtained from the first state detection camera 33, and recognize the rotation angle when passing through the first head unit 43 for other tablets 9 based on the captured image obtained from the second state detection camera 42. In addition, for some tablets 9, the rotation angle when passing through the second head unit 53 may be recognized based on the captured image obtained from the third state detection camera 52, and for other tablets 9, the rotation angle when passing through the second head unit 53 may be recognized based on the captured image obtained from the second state detection camera 42. However, the dividing line 91 may be formed on both the first and second surfaces of the tablet 9.

[0049] The head control unit 72 is a function for controlling the operation of the first head unit 43 and the second head unit 53. As shown in FIG. 5, the head control unit 72 has a first storage unit 721. The function of the first storage unit 721 is realized, for example, by the storage device 703 described above. The first storage unit 721 stores print image data D1. FIG. 7 is a diagram showing an example of a print image I represented by the print image data D1. The print image data D1 is data representing the print image I to be printed on the second surface of the tablet 9. The image is a product name, product code, company name, logo mark, etc., and is formed of a character string including, for example, alphabets and numbers. However, the image may be a mark or an illustration other than a character string. Furthermore, the image is printed on the second surface of the tablet 9 along the dividing line 91 on the first surface. However, the image may be printed on the first surface of the tablet 9 along the dividing line 91. The print image data D1 also includes information specifying the printing position and printing direction of the image on the tablet 9.

[0050] When printing on the surface of the tablet 9 as a product, the head control unit 72 reads out the print image data D1 from the first storage unit 721. The head control unit 72 also rotates the read out print image data D1 according to the rotation angle recognized by the angle recognition unit 71. The head control unit 72 then controls the first head 431 or the second head 531 based on the rotated print image data D1. As a result, the image represented by the print image data D1 is printed on the surface of the tablet 9 along the dividing line 91.

[0051] The inspection unit 73 has a function for detecting defects in images printed on the surfaces of the tablets 9 transported by the first transport conveyor 41 and the tablets 9 transported by the second transport conveyor 51. As shown in FIG. 5, the inspection unit 73 has a second storage unit 731. The function of the second storage unit 731 is realized, for example, by the above-mentioned storage device 703. The second storage unit 731 stores inspection image data D2. The inspection image data D2 is generated based on the print image data D1.

[0052] When inspecting the tablet 9 after printing, the inspection unit 73 reads out the inspection image data D2 for inspection from the second storage unit 731. Then, the inspection unit 73 rotates the read-out inspection image data D2 according to the rotation angle recognized by the angle recognition unit 71. The inspection unit 73 also acquires the photographed image data Dp of the tablet 9 after printing from the first inspection camera 44. The inspection unit 73 detects defects in the image printed on the surface of the tablet 9 by comparing the rotated inspection image data D2 for inspection with the photographed image data Dp acquired from the first inspection camera 44. Specifically, if there is a difference between the inspection image data D2 and the photographed image data Dp that is equal to or greater than a preset threshold value, the inspection unit 73 detects the corresponding portion as a defect. Similarly, the inspection unit 73 detects defects in the image printed on the surface of the tablet 9 by comparing the rotated inspection image data D2 for inspection with the photographed image data Dp acquired from the second inspection camera 54. As a result, the inspection of the printing state of all the tablets 9 is completed.

[0053] <3. Effect of preheating> As described above, in the tablet printing device 1 of this embodiment, the first head 431 ejects ink droplets onto the surface of the tablet 9 transported by the first transport conveyor 41, and the second head 531 ejects ink droplets onto the surface of the tablet 9 transported by the second transport conveyor 51. The tablet printing device 1 also has a feeder section 20 that supplies the tablet 9 upstream of the transport path from the first transport conveyor 41 and the second transport conveyor 51. The preheat section 25 heats the tablet 9 in the feeder section 20. That is, the tablet printing process performed in the tablet printing device 1 of this embodiment includes a) a step of heating the tablet 9, and b) a step of ejecting ink droplets onto the surface of the heated tablet 9 after step a). The results of verifying the effect of heating the tablet 9 before the ink droplets are ejected onto the surface of the tablet 9 by the preheat section 25 are described below.

[0054] FIG. 8 shows the results of verifying the difference in state of tablet 9, which is an enteric film-coated tablet, when it is finally conveyed out of the tablet printing device 1 as a non-defective product and rubbed several times with a finger between a case in which tablet 9 is heated in the preheating unit 25 before undergoing a printing process on tablet 9, which is an enteric film-coated tablet, in this embodiment and a case in which tablet 9 is not heated before undergoing a printing process. In FIG. 8, the left side shows a case in which tablet 9 is heated before undergoing a printing process on tablet 9, and the right side shows a case in which tablet 9 is not heated before undergoing a printing process on tablet 9. In addition, in FIG. 8, the upper side shows a case in which printing is performed using pigment ink, and the lower side shows a case in which printing is performed using dye ink.

[0055] As shown in FIG. 8, it was visually confirmed that the ink was less likely to peel off (become thinner) from the tablet 9 after the printing process when the tablet 9 was heated in the preheating unit 25 before the printing process of the tablet 9 (left side) than when the tablet 9 was not heated before the printing process (right side). In other words, it was confirmed that when the tablet 9 was heated in the preheating unit 25 before the printing process of the tablet 9, the fixation of the ink on the surface of the tablet 9 after the printing process was improved. Furthermore, similar results were confirmed not only when the printing process was performed using pigment ink (upper side) but also when the printing process was performed using dye ink (lower side).

[0056] FIG. 9 shows the results of verifying the difference in state of a tablet 9 finally transported to the outside of the tablet printing device 1 as a non-defective product when the tablet 9 is rubbed several times with a finger between a case where the tablet 9, which is a sugar-coated tablet, is heated in the preheating unit 25 before the printing process is performed and a case where the tablet 9 is not heated before the printing process is performed, as a modified example. In FIG. 9, the left side shows the case where the tablet 9 is heated before the printing process is performed on the tablet 9, and the right side shows the case where the tablet 9 is not heated before the printing process on the tablet 9. Also, in FIG. 9, the upper side shows the case where the printing process is performed using pigment ink, and the lower side shows the case where the printing process is performed using dye ink.

[0057] As shown in FIG. 9, even if the tablet 9 is a sugar-coated tablet, it was visually confirmed that the ink is less likely to peel off (become thinner) from the tablet 9 after the printing process when the tablet 9 is heated in the preheating unit 25 before the printing process (left side) than when the tablet 9 is not heated before the printing process (right side). In other words, it was confirmed that when the tablet 9 is heated in the preheating unit 25 before the printing process of the tablet 9, the fixation of the ink on the surface of the tablet 9 after the printing process is improved. In addition, similar results were confirmed not only when the printing process was performed using pigment ink (upper side) but also when the printing process was performed using dye ink (lower side).

[0058] FIG. 10 shows the results of verifying the difference in state of the tablet 9 finally transported to the outside of the tablet printing device 1 as a non-defective product when it is rubbed with a finger several times between a case where the tablet 9 is heated in the preheating unit 25 before the printing process of the tablet 9, which is a plain tablet, as a modified example, and a case where the tablet 9 is not heated before the printing process. In FIG. 10, the left side shows the case where the tablet 9 is heated before the printing process of the tablet 9, and the right side shows the case where the tablet 9 is not heated before the printing process of the tablet 9. As shown in FIG. 10, even if the tablet 9 is a plain tablet, it was visually confirmed that the ink is less likely to peel off (become less thin) from the tablet 9 after the printing process when the tablet 9 is heated in the preheating unit 25 before the printing process of the tablet 9 (left side) than when the tablet 9 is not heated before the printing process (right side).

[0059] There are various reasons why the fixability of the ink is improved by pre-heating the tablet 9. For example, one reason is that the surface of the tablet 9 is modified by pre-heating the tablet 9, suppressing the above-mentioned bulge phenomenon. In addition, the first after-heating section 45 and the second after-heating section 55 heat the ink from the outside of the tablet 9, but in addition to this, the ink attached to the surface of the tablet 9 also receives heat from the tablet 9 located inside, which is also considered to be a reason why the fixability is improved. In addition, when ink droplets are ejected onto the surface of the tablet 9, the ink immediately receives heat from the tablet 9, and the ink starts to fix. This is also considered to be a reason why the fixability is improved.

[0060] <4. Modifications> Although the main embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment.

[0061] In the above-described embodiment, the preheating unit 25 is provided at only one location on the conveying path of the tablet printing device 1. However, the preheating unit 25 may be provided at multiple locations on the conveying path of the tablet printing device 1. For example, in addition to the preheating unit 25 of the above-described embodiment, an additional preheating unit may be provided on the conveying path between the first head unit 43 and the second head unit 53.

[0062] In the above embodiment, the inspection unit 73 rotates the test image data D2 according to the rotation angle of the tablet 9. However, the second storage unit 731 may store a plurality of test image data D2 with different rotation angles (for example, 360 test image data D2 with rotation angles differing by 1°) in advance. The inspection unit 73 may then read out the test image data D2 with a rotation angle according to the recognition result of the angle recognition unit 71 from the second storage unit 731 and perform the inspection. In this way, the calculation burden on the inspection unit 73 can be reduced compared to the case where the test image data D2 is rotated one by one for each tablet 9. Therefore, the inspection of the printed image can be performed quickly.

[0063] Furthermore, the above-described tablet printing device 1 is a device that prints on both sides of the tablet 9 by the first printing unit 40 and the second printing unit 50. However, the tablet printing device of the present invention may be a device that prints on only one side of the tablet 9.

[0064] In the above-described embodiment, the first printing unit 40 and the second printing unit 50 each have four heads. However, the number of heads included in each of the printing units 40, 50 may be one to three, or may be five or more.

[0065] In addition, the detailed configuration of the tablet printing apparatus 1 may differ from that shown in the drawings of the present application. In addition, the elements appearing in the above-mentioned embodiment and modified examples may be appropriately combined within the scope of not causing any contradiction. [Explanation of symbols]

[0066] 1 Tablet printing equipment 9 tablets 10 Hopper 20 Feeder section 22 Rotary feeder 25 Preheat section 30 Transport drum 33 First condition detection camera 40 1st Printing Department 41 First conveyor 42 Second state detection camera 43 First head unit 44 First Inspection Camera 45 First Afterheat Section 50 2nd Printing Department 51 Second conveyor 52 3rd state detection camera 53 Second head unit 54 2nd Inspection Camera 55 Second Afterheat Section 56 Defective Product Collection Department 60 Discharge Conveyor 70 Control section 91 secant line 100 Case 221 Turntable 411 First pulley 412 First conveyor belt 431 Head 1 511 Second pulley 512 Second conveyor belt 531 2nd Head D1 Print image data D2 Inspection image data Dp Shooting image data I Printed image

Claims

1. A tablet printing device that prints an image on a surface of a tablet, a first transport conveyor that transports the tablet while holding the other surface of the tablet; A first printing unit that prints an image on one side of the tablet transported by the first transport conveyor; a first preheating unit that heats tablets, the first preheating unit being located upstream of the first printing unit in a conveying path; a second conveyor that conveys the tablet delivered from the first conveyor while holding the one surface of the tablet; A second printing unit that prints an image on the other surface of the tablet transported by the second transport conveyor; a second preheating unit that heats tablets downstream of the first printing unit and upstream of the second printing unit in the conveying path; A platform that conveys tablets placed on its upper surface by rotating itself; having The tablet placed on the upper surface of the table is heated by the first preheating unit while moving relative to the first preheating unit as the table rotates. Tablet printing equipment.

2. The tablet printing apparatus according to claim 1, A tablet printing device, wherein the first preheating unit or the second preheating unit heats the tablets by supplying warm air or hot air toward the tablets.

3. The tablet printing apparatus according to claim 1, A tablet printing device, wherein the first preheating unit or the second preheating unit heats the tablet by emitting far infrared rays toward the tablet.

4. The tablet printing device according to claim 2, A tablet printing apparatus, wherein the temperature of the warm or hot air is 40°C or higher and 140°C or lower.

5. The tablet printing device according to any one of claims 1 to 3, The first printing unit and the second printing unit print images by ejecting ink droplets onto a surface of the tablet, A tablet printing device, wherein the ejected ink droplets are droplets of pigment ink.

Images