JP7353451B2 - Tablet printing device and tablet printing method - Google Patents

Description

The present invention relates to a printing device and a printing method for printing images on tablets using an inkjet method.

Characters and codes are printed on pharmaceutical tablets to identify the product. Such characters and codes may be recorded by engraving, but engraving has a problem of low visibility. In particular, in recent years, the types of tablets have diversified due to the spread of generic drugs. For this reason, there is a demand for clear printing on the surface of tablets so that the tablets can be reliably identified. Further, since tablets are sensitive to pressure, it is preferable to reduce the pressure applied to the tablets during printing. Due to these circumstances, technology for printing images on tablets using an inkjet method has been attracting attention in recent years.

Conventional printing devices that print images on tablets using an inkjet method are described in, for example, Patent Document 1 and Patent Document 2.

Japanese Patent Application Publication No. 6-143539 JP 2017-534 Publication

The solid dosage printing apparatus of Patent Document 1 includes a heater, a hot air dryer, etc. (180) for sufficiently drying the ink transferred to the solid dosage form (200) before collection of the solid dosage form (200). Further, the tablet printing apparatus (1) of Patent Document 2 includes a heater that supplies radiant heat or a blower that supplies warm air or hot air to dry the ink applied to the tablet (T).

However, for example, in the case of tablets such as film-coated tablets (FC tablets) and sugar-coated tablets, which have a highly liquid-repellent surface and are difficult for liquid to penetrate, when the surface tension of the ink applied to the tablet is high, or when the ink is If the ink is difficult to dry, there is a possibility that after the ink is applied to the tablet, the applied ink flows on the surface of the tablet to minimize the surface area (bulge phenomenon). In this case, even if the tablet is subsequently dried and further subjected to a coating treatment, etc., the ink will be difficult to adhere to the tablet, and there is a risk that the ink will peel off from the tablet due to slight contact such as rubbing.

The present invention was developed in view of the above circumstances, and is applicable when ink droplets are ejected onto tablets such as film-coated tablets (FC tablets) and sugar-coated tablets, which have a highly liquid-repellent surface and are difficult to penetrate with liquid. However, the purpose is to provide a technology that can prevent the ink from peeling off from the tablet afterwards.

In order to solve the above problems, a first invention of the present application is a tablet printing device that prints an image on the surface of a tablet using an inkjet method, which includes a transport mechanism that transports the tablet along a predetermined transport route, and a transport mechanism that transports the tablet along a predetermined transport route. A head for discharging ink droplets onto the surface of a tablet being transported by the tablet, and a preheating section for heating the tablet on the upstream side of the transport path from the head.

A second invention of the present application is the tablet printing apparatus of the first invention, in which the preheat section heats the tablet by supplying warm air or hot air toward the tablet.

A third invention of the present application is the tablet printing apparatus according to the second invention, wherein the temperature of the warm air or hot air is 40°C or higher and 140°C or lower.

A fourth invention of the present application is the tablet printing apparatus according to any one of the first to third inventions, wherein the transport mechanism includes a transport conveyor that moves the transport belt while adsorbing tablets to the transport belt. , a feeder unit that supplies tablets on the upstream side of the transport route than the transport conveyor; the head discharges ink droplets onto the surface of the tablets transported by the transport conveyor; The tablets are heated in the feeder section.

A fifth invention of the present application is the tablet printing device according to any one of the first to fourth inventions, further comprising an afterheating section that heats the tablets on the downstream side of the conveyance path from the head. .

A sixth invention of the present application is the tablet printing apparatus according to any one of the first to fifth inventions, wherein the tablet is an enteric film coated tablet.

A seventh invention of the present application is the tablet printing apparatus according to any one of the first to sixth inventions, wherein the ink droplets discharged from the head are pigment ink droplets.

An eighth invention of the present application is a tablet printing method for printing an image on the surface of a tablet by an inkjet method, comprising: a) heating the tablet; and b) after step a), ink droplets are printed on the surface of the tablet. and a step of discharging.

According to the first to eighth inventions of the present application, by ejecting ink droplets onto the surface of the tablet after heating the tablet, the fixability of the ink on the surface of the tablet is improved. As a result, subsequent peeling of the ink from the tablet can be suppressed.

In particular, according to the second or third invention of the present application, it is easy to uniformly heat a plurality of tablets. Moreover, overheating of the tablets can be easily prevented. Furthermore, tablets can be heated without significantly changing the configuration of a conventional tablet printing device.

In particular, according to the fourth invention of the present application, the preheating section that heats the tablet is located at a position away from the head that ejects ink droplets. Thereby, it is possible to suppress the heat from the preheating section from having an adverse effect on the head.

In particular, according to the fifth invention of the present application, the tablet is further heated after the ink droplets are ejected onto the surface of the tablet. This further improves the fixation of the ink on the surface of the tablet.

1 is a diagram showing the configuration of a tablet printing device. FIG. 3 is a perspective view of the vicinity of the conveyance drum. FIG. 3 is a bottom view of the head. FIG. 2 is a block diagram showing connections between a control unit and various parts within the tablet printing device. FIG. 2 is a block diagram conceptually showing part of the functions of a control unit. It is a top view of several tablets conveyed by the 1st conveyor. FIG. 3 is a diagram showing an example of a printed image. FIG. 3 is a diagram showing the results of verifying the effect of heating a tablet, which is an enteric film coated tablet, before ejecting ink droplets onto the tablet. FIG. 2 is a diagram showing the results of verifying the effect of heating a sugar-coated tablet before ejecting ink droplets onto the tablet. FIG. 2 is a diagram showing the results of verifying the effect of heating a plain tablet before ejecting ink droplets onto the tablet.

Embodiments of the present invention will be described below with reference to the drawings. In addition, in the following description, the direction in which a plurality of tablets are conveyed will be referred to as the "transportation direction", and the direction perpendicular and horizontal to the transportation direction will be referred to as the "width direction".

<1. Configuration of tablet printing device>
The configuration of a tablet printing apparatus 1 according to an 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 apparatus 1 according to an embodiment of the present invention. The tablet printing apparatus 1 of this embodiment is an apparatus that prints images such as a product name, product code, company name, logo mark, etc. on the surface of each tablet 9 using an inkjet method while conveying a plurality of tablets 9.

For the tablet 9 of this embodiment, for example, an enteric film-coated tablet (enteric-coated FC tablet) whose surface is coated and has high liquid repellency is used. However, the tablet 9 may be a sugar-coated tablet, or may be a non-coated tablet such as an orally disintegrating tablet (OD tablet) or a plain tablet (uncoated tablet). Moreover, the tablet 9 may be a capsule including a hard capsule and a soft capsule. Moreover, 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 confectionery such as ramune. Further, the tablet 9 of the present embodiment has a flat spherical three-dimensional shape, for example, as shown in FIGS. 8 to 10, which will be described later. However, the shape of the tablet 9 is not limited to this.

As shown in FIG. 1, the tablet printing apparatus 1 of this embodiment includes a hopper 10, a feeder section 20, a preheat section 25, a conveyance drum 30, a first printing section 40, a second printing section 50, an output conveyor 60, and a control unit. It has a section 70. The tablets 9 are transported along a predetermined transport path by the hopper 10, the feeder section 20, the transport drum 30, the first transport conveyor 41 of the first printing section 40, the second transport conveyor 51 of the second printing section 50, and the transport conveyor 60. A transport mechanism is formed to transport the paper.

The hopper 10 is an input section for receiving a large number of tablets 9 into the device at once. The hopper 10 is arranged at the top of the housing 100 of the tablet printing device 1. The hopper 10 has an opening 11 located on the top surface of the housing 100 and a funnel-shaped slope 12 that gradually converges toward the bottom. The plurality of tablets 9 (enteric film coated tablets) introduced into the opening 11 flow into the linear feeder 21 along the inclined surface 12.

The feeder section 20 is a mechanism that transports the plurality of tablets 9 put into the hopper 10 to the transport drum 30. The feeder section 20 of this embodiment includes a linear feeder 21, a rotary feeder 22, and a supply feeder 23. The linear feeder 21 has a flat vibration trough 211. The plurality of tablets 9 supplied from the hopper 10 to the vibrating trough 211 are conveyed to the rotary feeder 22 side by the vibration of the vibrating trough 211. The rotary feeder 22 has a disc-shaped rotary table 221. The plurality of tablets 9 that have fallen from the vibrating trough 211 onto the upper surface of the rotary table 221 gather near the outer periphery of the rotary table 221 due to the centrifugal force caused by the rotation of the rotary table 221.

The supply feeder 23 has a plurality of cylindrical portions 231 that extend vertically downward from the outer periphery of the rotary table 221 to the conveyance drum 30. FIG. 2 is a perspective view of the vicinity of the transport drum 30. As shown in FIG. 2, a plurality of (eight in the example of FIG. 2) cylindrical portions 231 are arranged parallel to each other. The plurality of tablets 9 conveyed to the outer peripheral part of the rotary table 221 are each supplied to one of the plurality of cylindrical parts 231 and fall within the cylindrical part 231. Then, a plurality of tablets 9 are stacked inside each cylindrical portion 231. In this way, the plurality of tablets 9 are distributed and supplied to the plurality of cylindrical parts 231, thereby being arranged in a plurality of transport lines. Then, the plurality of tablets 9 in each conveyance row are supplied to the conveyance drum 30 in order from the bottom one.

A preheat section 25 is provided above the rotary feeder 22. The preheat section 25 is fixed to the housing 100 of the tablet printing apparatus 1. The preheating section 25 is a mechanism that heats the tablet 9 by supplying warm air or hot air toward the tablet 9 being conveyed on the upper surface of the rotary table 221, for example. During the process of conveying the tablet 9 on the upper surface of the rotary table 221, the tablet 9 is heated by hot air or hot air from the preheating section 25 for several seconds to several minutes. Thereby, the plurality of tablets 9 can be heated almost uniformly. Further, the temperature of the warm air or hot air supplied from the preheat section 25 toward the tablets 9 is, for example, 40°C or higher and 140°C or lower. Thereby, overheating of the tablet 9 can be suppressed. Furthermore, for the preheating section 25, for example, a commercially available heater or dryer is used. However, the preheating section 25 may include a device (for example, a heater, etc.) that heats the tablet 9 by emitting far infrared rays. With such a configuration, it is possible to print on the upstream side of the conveyance path from the location where ink droplets are ejected onto the tablet 9 (the first head 431 and the second head 531, which will be described later), without significantly changing the configuration of the conventional tablet printing device. Tablets 9 can be heated.

The plurality of tablets 9 heated by the preheat section 25 pass through the supply feeder 23 and the conveyance drum 30 and reach the first printing section 40 and the second printing section 50. As described above, the preheat section 25 of this embodiment is arranged at a position away from the first head 431 and second head 531, which will be described later, that eject ink droplets onto the tablet 9. Thereby, it is possible to suppress the heat from the preheat section 25 from having an adverse effect on the first head 431 and the second head 531. However, the position where the preheating section 25 is provided may be upstream of the first head unit 43 (described later) of the first printing section 40, and is limited to the position above the rotary feeder 22 as in the present embodiment. Not done. Note that the effect of heating the tablet 9 by the preheating section 25 before ink droplets are ejected onto the surface of the tablet 9 will be described in detail later.

The conveyance drum 30 is a mechanism that delivers a plurality of tablets 9 from the supply feeder 23 to the first conveyor 41. The conveyance drum 30 has a substantially cylindrical outer peripheral surface. The conveyance drum 30 rotates in the direction of the arrow in FIGS. 1 and 2 about a rotation shaft extending in the width direction by power obtained from a motor (not shown). As shown in FIG. 2, a plurality of holding parts 31 are provided on the outer peripheral surface of the conveyance drum 30. The holding portion 31 is a recessed portion that is recessed inward from the outer circumferential surface of the conveyance drum 30 . The plurality of holding parts 31 are arranged along the circumferential direction on the outer peripheral surface of the conveyance drum 30 at widthwise positions corresponding to each of the plurality of conveyance lines described above. Further, a suction hole 32 is provided at the bottom of each holding portion 31 .

A suction mechanism (not shown) is provided inside the conveyance 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 unit 31 suction-holds the tablets 9 supplied from the supply feeder 23 one by one using the negative pressure. Furthermore, a blow mechanism (not shown) is provided inside the conveyance drum 30. The blow mechanism blows locally pressurized gas from the inside of the conveyance drum 30 toward the first conveyor 41 side, which will be described later. As a result, the adsorption state of the tablets 9 is maintained in the holding parts 31 that do not face the first transport conveyor 41, and the adsorption of the tablets 9 is released only in the holding parts 31 that face the first transport conveyor 41. In this way, the conveyance drum 30 rotates while sucking and holding the plurality of tablets 9 supplied from the supply feeder 23, and can deliver these tablets 9 to the first conveyor 41.

A first state detection camera 33 is provided at a position facing the outer peripheral surface of the transport drum 30. The first state detection camera 33 is an imaging unit that photographs the state of the tablet 9 held on the transport drum 30. The first state detection camera 33 photographs the tablet 9 being conveyed by the conveyance drum 30 and transmits the obtained image to the control unit 70 . The control unit 70 detects the presence or absence of the tablet 9 in each holding part 31, the front and back sides of the tablet 9 held in the holding part 31, and the rotation angle, based on the received image.

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

The first conveyor 41 includes a pair of first pulleys 411 and a first annular conveyor belt 412 stretched between the pair of first pulleys 411 . The first conveyor belt 412 is arranged such that a portion thereof is close to and faces the outer peripheral surface of the conveyor drum 30. One of the pair of first pulleys 411 is rotated by power obtained from a motor (not shown). As a result, the first conveyor 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 as the first conveyor belt 412 rotates.

As shown in FIG. 2, the first conveyor belt 412 is provided with a plurality of holding parts 413. The holding portion 413 is a recessed portion that is recessed from the outer surface of the first conveyor belt 412 toward the inner side. The plurality of holding parts 413 are arranged in the transport direction at widthwise positions corresponding to each of the plurality of transport lines. That is, the plurality of holding parts 413 are arranged at intervals in the width direction and the conveyance direction, respectively. The widthwise interval between the plurality of holding parts 413 on the first conveyance belt 412 is equal to the widthwise interval between the plurality of holding parts 31 on the conveyance drum 30.

A suction hole 414 is provided at the bottom of each holding portion 413 . Further, the first conveyor 41 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 unit 413 suction-holds the tablets 9 passed from the conveyance drum 30 one by one by the negative pressure. Thereby, the first transport conveyor 41 transports the plurality of tablets 9 while holding them in a state in which they are aligned in a plurality of transport 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 holes 414 in the holding part 413 facing the second conveyor 51, which will be described later, become under a positive pressure higher than atmospheric pressure. As a result, the adsorption of the tablets 9 in the holding section 413 is released, and the tablets 9 are transferred from the first conveyor 41 to the second conveyor 51. Note that when the tablet 9 is transferred from the first conveyor 41 to the second conveyor 51, the tablets 9 are turned over.

The second state detection camera 42 is an imaging unit that photographs the state of the tablets 9 held on the first transport conveyor 41 on the upstream side of the first head unit 43 in the transport direction. The first state detection camera 33 and the second state detection camera 42 photograph opposite sides of the tablet 9. The image obtained by the second state detection camera 42 is transmitted from the second state detection camera 42 to the control unit 70. Based on the received image, the control unit 70 detects the presence or absence of the tablet 9 in each holding part 413, the front and back sides of the tablet 9 held in the holding part 413, and the rotation angle.

The first head unit 43 is an inkjet type head unit that discharges ink droplets toward the surface of the tablet 9 being conveyed by the first 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 multicolor image is printed on the surface of the tablet 9 by overlapping the monochrome images formed by these colors. Note that the ink ejected from each first head 431 is an edible ink manufactured from raw materials approved by the Japanese Pharmacopoeia, the Food Sanitation Act, and the like. Further, 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.

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 shown by two-dot chain lines. As shown in an enlarged view in FIG. 3, a plurality of nozzles 430 capable of ejecting ink droplets are provided on the lower surface of the first head 431. In this embodiment, a plurality of nozzles 430 are two-dimensionally arranged on the lower surface of the first head 431 in the transport direction and the width direction. The nozzles 430 are arranged with their positions shifted in the width direction. In this way, by arranging the plurality of nozzles 430 two-dimensionally, the positions of the nozzles 430 in the width direction can be made close to each other. However, the plurality of nozzles 430 may be arranged in a line along the width direction.

As a method for ejecting ink droplets from the nozzle 430, for example, a so-called piezo method is used in which the ink in the nozzle 430 is pressurized and ejected by applying a voltage to a piezo element to deform it. However, the ink droplet ejection method may be a so-called thermal method in which the ink droplets are ejected by energizing a heater to heat and expand the ink in the nozzle 430.

Return to Figure 1. The first inspection camera 44 is an imaging unit for checking the print result by the first head unit 43. The first inspection camera 44 photographs the tablet 9 being conveyed by the first conveyance belt 412 on the downstream side of the first head unit 43 in the conveyance direction. Further, the first inspection camera 44 transmits the obtained image to the control unit 70. Based on the received image, the control unit 70 inspects the image printed on the surface of each tablet 9 to see if there are any printing defects such as misalignment or missing dots.

The first afterheat section 45 is a mechanism that heats the tablets 9 that are transported downstream of the first head 431 on the transport path. The first after-heat section 45 uses, for example, a hot air drying type heater that blows hot air toward the tablets 9 being conveyed by the first conveyor 41. When the tablet 9 passes near the first afterheat section 45, the ink ejected onto the surface of the tablet 9 in the first head unit 43 is dried by hot air and fixed on the surface of the tablet 9. Note that in this embodiment, the first afterheat section 45 is arranged downstream of the first inspection camera 44 in the transport direction. However, the first afterheat section 45 may be arranged between the first head unit 43 and the first inspection camera 44.

The second printing unit 50 is a processing unit that prints 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 section 50 includes a second conveyor 51, a third state detection camera 52, a second head unit 53, a second inspection camera 54, a second afterheating section 55, and a defective product recovery section. It has a section 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 being transported by the second transport conveyor 51 on the upstream side of the second head unit 53 in the transport direction. The second head unit 53 discharges 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 second head unit 53 in the conveyance direction. The second after-heat section 55 heats the tablet 9 being transported downstream of the second head 531 on the transport path. As a result, the ink ejected onto the surface of the tablet 9 in the second head unit 53 is dried by the hot air and fixed on the surface of the tablet 9.

For details of each of the second conveyor 51, third state detection camera 52, second head unit 53, second inspection camera 54, and second afterheat section 55, see the above-mentioned first conveyor 41 and second state detection camera 52. Since they are equivalent to the detection camera 42, the first head unit 43, the first inspection camera 44, and the first afterheat section 45, repeated explanation will be omitted.

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

The carry-out conveyor 60 is a mechanism that carries out a plurality of tablets 9 that are determined to be good products to the outside of the casing 100 of the tablet printing apparatus 1 . The upstream end of the carry-out conveyor 60 is located below the second pulley 511 of the second conveyor 51. The downstream end of the carry-out conveyor 60 is located outside the housing 100. For example, a belt conveyance mechanism is used for the discharge conveyor 60. The plurality of tablets 9 that have passed through the defective product collection section 56 fall from the second transport conveyor 51 onto the upper surface of the carry-out conveyor 60 when the suction of the suction holes is released. Then, the plurality of tablets 9 are carried out to the outside of the casing 100 by the carrying-out conveyor 60.

The control section 70 is a means for controlling the operation of each section within the tablet printing apparatus 1. FIG. 4 is a block diagram showing connections between the control section 70 and each section within the tablet printing apparatus 1. As conceptually shown in FIG. 4, the control unit 70 is constituted by 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 print processing and inspection processing are stored in the storage device 703.

Further, as shown in FIG. 4, the control unit 70 includes the above-described linear feeder 21, rotary feeder 22, preheat unit 25, conveyance drum 30 (including a motor, suction mechanism, and blow mechanism), and a first state detection camera 33. , a first conveyor 41 (including a motor, a suction mechanism, and a blow mechanism), a second state detection camera 42, a first head unit 43 (including a plurality of nozzles 430 of each first head 431), and a first inspection camera. 44, first afterheat section 45, second conveyor 51, third state detection camera 52, second head unit 53 (including a plurality of nozzles 430 of each second head 531), second inspection camera 54, second It is communicably connected to the afterheat section 55, the defective product collection section 56, and the carry-out conveyor 60, respectively.

The control unit 70 temporarily reads 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 operating each of the above-mentioned units. Control. As a result, the printing process for the plurality of tablets 9 proceeds.

<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 section 70 of this embodiment includes an angle recognition section 71, a head control section 72, and an inspection section 73. The functions of each of these parts are achieved by temporarily reading the computer program P and data D stored in the storage device 703 of the control unit 70 into the memory 702, and having the processor 701 perform arithmetic processing based on the computer program P. , realized.

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 state detection camera 33 and the second state detection camera 42, and recognizes the rotation angle of each tablet 9 conveyed by the first conveyor 41 based on the captured images. do. Further, the angle recognition unit 71 acquires a photographed image of the third state detection camera 52, and recognizes the rotation angle of each tablet 9 conveyed by the second conveyor 51 based on the photographed image.

FIG. 6 is a top view of the plurality of tablets 9 being conveyed by the first conveyor 41. In the example of FIG. 6, a scored tablet having a scored line 91 is transported as the tablet 9. It is necessary to print such a score line lock at a rotation angle corresponding to the direction of the score line 91. Therefore, the angle recognition unit 71 determines the rotation angle (secant line) of each tablet 9 when passing 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. 91 direction). Similarly, the angle recognition unit 71 recognizes, for each tablet 9, the rotation angle (orientation of the dividing line 91) when passing through the second head unit 53, based on the photographed image obtained from the third state detection camera 52. .

Note that the tablet 9 of this embodiment has a score line 91 only on the first surface of the first and second surfaces, which are the front and back surfaces. Further, the front and back sides of the plurality of tablets 9 to be transported are not constant. Therefore, as shown in FIG. 6, tablets 9 held with the first side facing upward and tablets 9 held with the second side facing upward are mixed and transported. There are cases. In such a case, the angle recognition unit 71 recognizes the rotation angle of some tablets 9 when passing through the first head unit 43 based on the captured image obtained from the first state detection camera 33. However, for other tablets 9, the rotation angle when passing through the first head unit 43 may be recognized based on the captured image obtained from the second state detection camera 42. Further, for some tablets 9, the rotation angle when passing through the second head unit 53 is 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 is recognized. The rotation angle when passing through the second head unit 53 may be recognized based on the photographed image obtained from the state detection camera 42 . However, the score line 91 may be formed on both the first and second surfaces of the tablet 9.

The head control section 72 has a function for controlling the operations of the first head unit 43 and the second head unit 53. As shown in FIG. 5, the head control section 72 includes a first storage section 721. The functions of the first storage unit 721 are 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 print image data D1. The print image data D1 is data representing the print image I to be printed on the second side of the tablet 9. The image is a product name, product code, company name, logo mark, etc., and is formed of, for example, a character string including alphabets and numbers. However, the image may be a mark or an illustration other than a character string. Further, the image is printed on the second side of the tablet 9 along the score line 91 on the first side. However, the image may be printed on the first side of the tablet 9 along the score line 91. The print image data D1 also includes information specifying the printing position and printing direction of the image on the tablet 9.

When printing on the surface of the tablet 9 as a product, the head control section 72 reads the print image data D1 from the first storage section 721. Further, the head control section 72 rotates the read print image data D1 according to the rotation angle recognized by the angle recognition section 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.

The inspection unit 73 is a function for detecting defects in images printed on the surface of the tablet 9 conveyed by the first conveyor 41 and the surface of the tablet 9 conveyed by the second conveyor 51. As shown in FIG. 5, the inspection section 73 includes a second storage section 731. The functions of the second storage unit 731 are realized, for example, by the storage device 703 described above. The second storage unit 731 stores inspection image data D2. Inspection image data D2 is generated based on print image data D1.

When inspecting the printed tablet 9, the inspection section 73 reads inspection image data D2 for inspection from the second storage section 731. Then, the inspection section 73 rotates the read inspection image data D2 according to the rotation angle recognized by the angle recognition section 71. The inspection unit 73 also acquires photographed image data Dp of the printed tablet 9 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 captured image data Dp acquired from the first inspection camera 44. do. 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 location is detected as a defect. Similarly, the inspection unit 73 compares the rotated inspection image data D2 for inspection with the captured image data Dp acquired from the second inspection camera 54, thereby determining the image printed on the surface of the tablet 9. Detect defects. As a result, the inspection of the printing state of all tablets 9 is completed.

<3. Effects of preheat>
As described above, in the tablet printing apparatus 1 of this embodiment, the first head 431 discharges ink droplets onto the surface of the tablet 9 conveyed by the first conveyor 41, and the second head 531 discharges ink droplets onto the surface of the tablet 9 conveyed by the first conveyor 41. Ink droplets are ejected onto the surface of the tablet 9 conveyed by the tablet 51. The tablet printing apparatus 1 also includes a feeder section 20 that supplies the tablets 9 upstream of the first conveyor 41 and the second conveyor 51 in the conveyance path. The preheat section 25 then heats the tablets 9 in the feeder section 20. That is, the tablet printing process executed in the tablet printing apparatus 1 of this embodiment includes a) a step of heating the tablet 9, and b) ejecting ink droplets onto the surface of the heated tablet 9 after step a). It has a process. The results of verifying the effect of heating the tablet 9 by the preheating section 25 before ink droplets are ejected onto the surface of the tablet 9 will be described below.

FIG. 8 shows a case where the tablet 9, which is an enteric film coated tablet, is heated in the preheating section 25 before the printing process is performed and a case where the tablet 9 is not heated before the printing process in this embodiment. The results of verifying the difference in the state of the tablet 9, which was finally carried out of the tablet printing apparatus 1 as a non-defective product and was rubbed several times with a finger, are shown in FIG. In FIG. 8, the left side shows the case where the tablet 9 is heated before the tablet 9 is subjected to the printing process, and the right side shows the case where the tablet 9 is not heated before the tablet 9 is subjected to the printing process. Moreover, in FIG. 8, the upper side shows the case where printing processing was performed using pigment ink, and the lower side shows the case where printing processing was performed using dye ink.

As shown in FIG. 8, the case where the tablet 9 is heated in the preheat section 25 before printing the tablet 9 (left side) is better than the case where the tablet 9 is not heated before the printing process (right side). Also, it was confirmed by visual observation that the ink was difficult to peel off from the tablet 9 (hard to become thin) after the printing process. That is, it was confirmed that when the tablet 9 was heated in the preheat section 25 before the printing process was performed on the tablet 9, the fixation of ink on the surface of the tablet 9 was improved after the printing process. Furthermore, similar results were observed not only when printing was performed using pigment ink (upper side), but also when printing was performed using dye ink (lower side).

FIG. 9 shows, as a modified example, a case in which the tablet 9 is heated in the preheat section 25 before the printing process is performed on the tablet 9, which is a sugar-coated tablet, and a case in which the tablet 9 is not heated before the printing process is performed. , shows the results of verifying the difference in condition when a tablet 9, which was finally transported out of the tablet printing apparatus 1 as a good product, is rubbed several times with a finger. In FIG. 9, the left side shows the case where the tablet 9 is heated before the tablet 9 is subjected to the printing process, and the right side shows the case where the tablet 9 is not heated before the tablet 9 is subjected to the printing process. Moreover, in FIG. 9, the upper side shows the case where printing processing was performed using pigment ink, and the lower side shows the case where printing processing was performed using dye ink.

As shown in FIG. 9, even if the tablet 9 is a sugar-coated tablet, it is better to heat the tablet 9 in the preheat section 25 before printing the tablet 9 (left side). Visual observation confirmed that the ink was less likely to peel off from the tablet 9 (less likely to become thinner) after the printing process than in the case without heating (right side). That is, it was confirmed that when the tablet 9 was heated in the preheat section 25 before the printing process was performed on the tablet 9, the fixation of ink on the surface of the tablet 9 was improved after the printing process. Furthermore, similar results were observed not only when printing was performed using pigment ink (upper side), but also when printing was performed using dye ink (lower side).

FIG. 10 shows, as a modified example, a case in which the tablet 9 is heated in the preheat section 25 before the printing process is performed on the uncoated tablet 9, and a case in which the tablet 9 is not heated before the printing process. The results of verifying the difference in the condition of the tablet 9, which was finally transported out of the tablet printing apparatus 1 as a non-defective product, when rubbed several times with a finger are shown. In FIG. 10, 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 tablet 9 is subjected to the printing process. As shown in FIG. 10, even if the tablet 9 is a plain tablet, the printing process is slightly better when the tablet 9 is heated in the preheating section 25 (on the left) before the printing process is performed on the tablet 9. Visual results confirmed that the ink was less likely to peel off from the tablet 9 (less likely to become thinner) after the printing process than when the tablet 9 was not heated before printing (right side).

There are various possible reasons why the preheating of the tablet 9 improves the fixability of the ink. For example, one possible reason is that the surface of the tablet 9 is modified by pre-heating the tablet 9, thereby suppressing the above-mentioned bulge phenomenon. Further, the first afterheat section 45 and the second afterheat 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 is heated from the inside. The fact that the tablet 9 also receives heat is also considered to be a reason why the fixing properties are improved. Another possible reason for the improved fixing performance is that when ink droplets are ejected onto the surface of the tablet 9, the ink immediately receives heat from the tablet 9 and starts fixing the ink.

<4. Modified example>
Although the main embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

In the embodiment described above, the preheat section 25 was provided only at one location on the conveyance path of the tablet printing device 1. However, the preheating sections 25 may be provided at multiple locations on the conveyance path of the tablet printing device 1. For example, in addition to the preheating section 25 of the embodiment described above, an additional preheating section may be provided on the transport path between the first head unit 43 and the second head unit 53.

Furthermore, in the embodiment described above, the inspection unit 73 rotates the inspection image data D2 according to the rotation angle of the tablet 9. However, the second storage unit 731 may store in advance a plurality of pieces of test image data D2 having different rotation angles (for example, 360 pieces of test image data D2 having different rotation angles of 1 degree). Then, the inspection unit 73 may read the inspection image data D2 of the 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 load on the inspection section 73 can be reduced compared to the case where the inspection image data D2 is rotated one by one for each tablet 9. Therefore, inspection of printed images can be performed quickly.

Moreover, the above-described tablet printing device 1 was a device that prints on both sides of the tablet 9 using the first printing section 40 and the second printing section 50. However, the tablet printing device of the present invention may be a device that prints only on one side of the tablet 9.

Furthermore, in the embodiment described above, each of the first printing section 40 and the second printing section 50 was provided with four heads. However, the number of heads included in each printing section 40, 50 may be from 1 to 3, or may be 5 or more.

Further, the detailed configuration of the tablet printing device 1 may be different from each figure of the present application. Furthermore, the elements appearing in the above-described embodiments and modifications may be combined as appropriate to the extent that no contradiction occurs.

1 Tablet printing device 9 Tablet 10 Hopper 20 Feeder section 22 Rotary feeder 25 Preheat section 30 Conveyance drum 33 First state detection camera 40 First printing section 41 First conveyor 42 Second state detection camera 43 First head unit 44 First Inspection camera 45 First afterheat section 50 Second printing section 51 Second conveyor 52 Third state detection camera 53 Second head unit 54 Second inspection camera 55 Second afterheat section 56 Defective product collection section 60 Carrying out conveyor 70 Control Part 91 Division line 100 Housing 221 Turntable 411 First pulley 412 First conveyor belt 431 First head 511 Second pulley 512 Second conveyor belt 531 Second head D1 Print image data D2 Inspection image data Dp Photographed image data I Print image

Claims (6)

A tablet printing device that prints an image on the surface of a tablet using an inkjet method,
a transport mechanism that transports the tablets along a predetermined transport route;
a head that discharges ink droplets onto the surface of the tablet conveyed by the conveyance mechanism;
a preheating section that heats the tablets on the upstream side of the conveyance path from the head;
has
The transport mechanism is
a conveyor that moves the conveyor belt while adsorbing tablets on the conveyor belt;
A feeder unit that supplies tablets on the upstream side of the conveyance path from the conveyor;
has
The head discharges ink droplets onto the surface of the tablet being conveyed by the conveyor,
The feeder section has a rotating feeder,
The preheating section is a tablet printing device that heats the tablets conveyed by the rotary feeder. The tablet printing device according to claim 1,
The preheating section is a tablet printing device that heats the tablets by supplying warm air or hot air toward the tablets. The tablet printing device according to claim 2,
The temperature of the warm air or hot air is 40°C or more and 140°C or less. The tablet printing device according to any one of claims 1 to 3,
The tablet printing device further includes an afterheating section that heats the tablets on the downstream side of the conveyance path from the head. The tablet printing device according to any one of claims 1 to 4,
A tablet printing apparatus, wherein the ink droplets ejected from the head are pigment ink droplets. A tablet printing method that prints an image on the surface of a tablet using an inkjet method while transporting the tablet along a transport path,
a) heating the tablets by a preheating section on the upstream side of the conveyance path from the head;
b) ejecting ink droplets from the head onto the surface of the tablet after step a);
has
In the step a), the preheating section heats the tablets conveyed by a rotary feeder.

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