JP2019162518A - Tablet printing device and tablet printing method - Google Patents

Abstract

To provide a tablet printing device and a tablet printing method capable of forming a printed image having a clear contour on the surface of a tablet.SOLUTION: This tablet printing device first irradiates at least one of an ultraviolet ray and an infrared ray toward the surface of a conveyed tablet 9. When the ultraviolet ray is irradiated, the surface of the tablet 9 is roughened, and the contact angle of ink is made small. Also, when the infrared ray is irradiated, the surface of the tablet 9 is etched into a concave shape. After that, ink I is discharged onto the surface of the tablet 9. This can improve the adhesion of the ink I to the tablet 9. Then, a deterioration in the quality of printing can be suppressed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a tablet printing apparatus and a tablet printing method for printing on the surface of a tablet.

  In order to identify the product, the surface of the tablet, which is a pharmaceutical product, is stamped at the time of tablet molding, or characters or codes are printed on the tablet after molding. Conventionally, a contact-type printing method has been used for printing on tablets. For example, a method of once transferring ink to a soft pad using a printing plate such as gravure printing and retransferring it to a tablet has been employed.

  However, in recent years, orally disintegrating tablets that can be taken without using water have gradually become widespread. Since orally disintegrating tablets are vulnerable to pressure, the contact printing method described above may damage the tablets due to the pressure of the printing plate. In other words, the printing method in which the printing plate comes into contact may lead to defective products. In addition, a scored lock that can be split in half along the score line is also widespread. When printing the scored lock, it is necessary to perform printing according to the direction of the scored line for each of the plurality of scored locks to be conveyed. For this reason, there is an increasing demand for an ink jet tablet printing apparatus that can perform non-contact printing and easily control the printing direction.

  An example of an ink jet type tablet printing apparatus is described in Patent Document 1, for example.

JP 2013-13711 A

  However, particularly in Europe and the United States, tablets in bottles may be provided to patients. In a tablet on which characters or the like are printed by a conventional ink jet printing method, the printed portion is rubbed in the bottle, the print quality is deteriorated, and there is a possibility that the identification of the tablet is lowered.

  In the ink jet printing method, an ink having a lower viscosity than that of a printing method using a printing plate is directly discharged onto a tablet. For this reason, depending on the component and surface state of the tablet, there is a problem that the ink flows on the surface of the tablet due to poor adhesion, and the printed characters are broken, or the outline of the printed image tends to be unclear. In particular, in recent years, with an increase in the types of generic drugs, there has been an increasing demand for printing a lot of information such as a manufacturer's logo and the amount of ingredients on a tablet for differentiation. In addition, tablets such as soft capsules, film-coated tablets, and sugar-coated tablets are difficult to print clearly by ink jet due to the surface condition of the tablets due to the influence of the material coated on the tablets. Sugar-coated tablets and the like may be coated with a wax component on the surface of the tablet to give gloss. In that case, when conventional ink jet printing is performed with a conventional aqueous ink for tablets, the ink cannot be stably fixed on the surface of the tablet having an oily tendency, and it is difficult to perform clear printing. In addition, in order to prevent the tablet from being mixed up, a barcode or QR code (registered trademark) may be printed on the tablet itself. For this reason, the technique which can print a fine image clearly on the surface of a tablet is calculated | required.

  This invention is made | formed in view of such a situation, and it aims at providing the tablet printing apparatus and tablet printing method which can form the printing image with a clear outline on the surface of a tablet.

  In order to solve the above problems, a first invention of the present application is a tablet printing apparatus that includes a transport mechanism that transports while holding a tablet, and that performs printing on the surface of the tablet, the surface of the tablet being transported by the transport mechanism An exposure portion that irradiates at least one of ultraviolet rays and infrared rays toward the surface, and an inkjet head that discharges ink toward the surface of the tablet that has passed through the exposure portion.

  A second invention of the present application is the tablet printing apparatus of the first invention, wherein the exposure unit irradiates at least one of ultraviolet rays and infrared rays on a region wider than a target region where a print image is to be formed.

  A third invention of the present application is the tablet printing apparatus according to the first invention, wherein the exposure unit irradiates the surface of the tablet with at least one of ultraviolet rays and infrared rays via a spatial modulation element or a crystal optical element.

  4th invention of this application is the tablet printing apparatus of 1st invention, Comprising: The said exposure part, The optical system which guides the light radiate | emitted from the light source which radiate | emits at least one of an ultraviolet-ray and infrared rays to a tablet, A housing that houses at least a part of the optical system and has a light-transmitting window positioned between the optical system and the transport mechanism.

  5th invention of this application is a tablet printing apparatus of 4th invention, Comprising: The said exposure part further has a ventilation mechanism which blows gas on the surface at the side of the said conveyance mechanism of the said window part.

  A sixth invention of the present application is the tablet printing apparatus according to any one of the first to fifth inventions, wherein the exposure unit irradiates at least one of ultraviolet and infrared laser beams.

  A seventh invention of the present application is the tablet printing apparatus according to any one of the first to fifth inventions, further comprising a fixing portion disposed downstream in the transport direction from the inkjet head, The fixing unit irradiates infrared rays by one or more methods of continuous irradiation, flash irradiation, and laser irradiation toward an irradiation region including at least a part of the printing region on the surface of the tablet.

  The eighth invention of the present application is a tablet printing method for printing on the surface of the tablet while transporting the tablet, a) a step of irradiating at least one of ultraviolet rays and infrared rays toward the surface of the tablet, and b) the above step. and a step of ejecting ink toward the surface of the tablet after a).

  A ninth invention of the present application is the tablet printing method of the eighth invention, and in the step a), at least one of ultraviolet rays and infrared rays is irradiated to a region wider than a target region where a printed image is to be formed.

  A tenth aspect of the present invention is the tablet printing method according to any one of the eighth aspect or the ninth aspect, wherein at least one of ultraviolet rays and infrared rays is irradiated in the step a).

  An eleventh invention of the present application is the tablet printing method according to any one of the eighth to tenth inventions, wherein after the step b), an irradiation region including at least a part of the printing region on the surface of the tablet is provided. Further, the method further includes a step of irradiating infrared rays by any one or more of continuous irradiation, flash irradiation, and laser irradiation.

  According to the first to eleventh inventions of the present application, the surface shape of the tablet is changed by at least one of ultraviolet rays and infrared rays. Then, ink is ejected toward the surface of the tablet. Thereby, the adhesiveness of the ink with respect to a tablet can also be improved. Therefore, it is possible to suppress a decrease in print quality.

  In particular, according to the second and ninth inventions of the present application, clear printing can be realized even if the alignment accuracy of the ink ejection position is somewhat low.

  In particular, according to the third invention of the present application, the light irradiation pattern can be easily controlled.

  In particular, according to the fourth invention of the present application, fine powder generated from a tablet can be prevented from adhering to the optical system.

  In particular, according to the fifth invention of the present application, fine powder generated from the tablet can be prevented from adhering to the window portion.

  In particular, according to the seventh and eleventh inventions of the present application, the printed part when the tablet is separated from the holding part and mixed by strengthening the drying of the ink surface by infrared irradiation after printing on the tablet. It becomes possible to reduce the damage of the ink surface.

It is the figure which showed the structure of the tablet printing apparatus which concerns on 1st Embodiment. It is the figure which showed the structure of the exposure part in 1st Embodiment. It is the block diagram which showed the structure of the control system in 1st Embodiment. It is the figure which showed the example of the irradiation pattern of the laser beam in 1st Embodiment. FIG. 3 is a diagram illustrating an example of an ink ejection range in the first embodiment. It is the figure which showed the change of the cross-sectional shape of the tablet in 1st Embodiment. It is the figure which showed the change of the cross-sectional shape of the tablet in 2nd Embodiment. It is the figure which showed the structure of the tablet printing apparatus which concerns on 3rd Embodiment. It is the figure which showed the example of the irradiation pattern of the laser beam in 3rd Embodiment. It is the figure which showed the change of the cross-sectional shape of the tablet in 3rd Embodiment. It is the figure which showed the example of the irradiation pattern of the laser beam in 4th Embodiment. It is the figure which showed the change of the cross-sectional shape of the tablet in 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, a direction in which a plurality of tablets are transported is referred to as a “transport direction”, and a direction perpendicular to the transport direction is referred to as a “width direction”.

<1. First Embodiment>
<1-1. Configuration of tablet printing device>
FIG. 1 is a diagram showing a configuration of a tablet printing apparatus 1 according to the first embodiment of the present invention. The tablet printing apparatus 1 is an apparatus that prints an image such as a product name, a product code, a company name, and a logo mark on the surface of each tablet 9 while conveying a plurality of tablets 9 that are medicines. As shown in FIG. 1, the tablet printing apparatus 1 of this embodiment includes a transport mechanism 10, an exposure / printing unit 20, and a control unit 70.

  The transport mechanism 10 is a mechanism that transports a plurality of tablets 9 while holding them. The transport mechanism 10 includes a transport belt 11 that is an annular flat belt. The conveyor belt 11 is stretched between a pair of pulleys (not shown). Further, the conveyance belt 11 is provided with a plurality of suction holes 12. The plurality of suction holes 12 are regularly arranged on the surface of the transport belt 11. In addition, a suction mechanism (not shown) is provided inside the conveyor belt 11. The suction mechanism generates a negative pressure lower than the atmospheric pressure in each of the plurality of suction holes 12. The tablets 9 are sucked and held in the suction holes 12 one by one by the negative pressure. When the pulley is rotated by the power of the motor, the conveyor belt 11 rotates between the pair of pulleys. Thereby, the plurality of tablets 9 held on the conveyor belt 11 are conveyed in the direction of the white arrow in FIG.

  The exposure / printing unit 20 determines the direction of the plurality of tablets 9 conveyed by the conveyance mechanism 10 (the direction of the rotation direction with respect to the vertical axis passing through the center of the suction hole 12), and based on the determination result, This is a part for printing a designated image on the surface. As shown in FIG. 1, the exposure / printing unit 20 of the present embodiment includes an image acquisition unit 30, an exposure unit 40, an inkjet head 50, and a fixing unit 60.

  The image acquisition unit 30 acquires images of a plurality of tablets 9 before printing held by suction on the conveyor belt 11. For the image acquisition unit 30, for example, a camera having a light receiving element such as a CCD or CMOS is used. The image acquisition unit 30 photographs the upper surface of the conveyance belt 11 from above the conveyance belt 11 and transmits the obtained image data to the control unit 70. Based on the received image data, the controller 70 detects whether or not the tablets 9 are held in the plurality of suction holes 12 of the transport belt 11. Further, the control unit 70 detects the orientation and position of the tablet 9 held in each suction hole 12 based on the received image data. Based on the detected information, the control unit 70 selects exposure data used for exposure and print data used for inkjet printing, and calculates the exposure position and the print position.

  The exposure unit 40 is a part that irradiates a laser beam toward the surface of the tablet 9 that is transported by the transport mechanism 10. The control unit 70 gives a light irradiation instruction to the exposure unit 40 according to the direction of each tablet 9 being conveyed. The exposure unit 40 irradiates the surface of the tablet 9 with laser light in accordance with an instruction from the control unit 40. FIG. 2 is a diagram showing the configuration of the exposure unit 40. As shown in FIG. 2, the exposure unit 40 of this embodiment includes a laser oscillator 41, a spatial modulation element 42, a condenser lens 43, a housing 44, and a blower mechanism 45.

  The laser oscillator 41 is a light source that emits laser light. The laser oscillator 41 of the present embodiment emits ultraviolet laser light. The wavelength of the laser light is, for example, 700 nm or more. Laser light emitted from the laser oscillator 41 is guided to the tablet 9 by an optical system 46 including a spatial modulation element 42 and a condensing lens 43.

  The spatial modulation element 42 is a means for reflecting the laser light emitted from the laser oscillator 41 while shaping it into an arbitrary shape. The spatial modulation element 42 has a plurality of fine mirrors arranged on the substrate. The spatial modulation element 42 finely displaces each mirror based on the electrical signal from the control unit 70. Thereby, the irradiation pattern of the laser beam which goes to the tablet 9 is shape | molded in the shape according to the image which should be printed. Examples of the spatial modulation element 42 include GLV (Grating Light Valve) (registered trademark) using diffraction of laser light and DMD (Digital Micro-mirror Device: digital micromirror) using reflection. -Devices) can be used. In addition, a crystal optical element that utilizes a change in refractive index by energization, or a galvanometer mirror that can form an irradiation pattern with a combination of a plurality of rotating mirrors can be used. The laser light molded in the spatial modulation element 42 is condensed by the condensing lens 43 and irradiated on the surface of the tablet 9. Thereby, the surface of the tablet 9 is exposed.

  The housing 44 is a housing that houses at least a part of the optical system 46. A window portion 441 made of a light transmissive material (for example, transparent glass) is provided on the bottom surface of the housing 44. The window 441 is located between the condenser lens 43 and the transport belt 11. The laser light that has passed through the condenser lens 43 passes through the window portion 441 and is irradiated on the surface of the tablet 9. The space in which the optical system 46 is disposed and the space in which the transport mechanism 10 for the tablet 9 is disposed are separated from each other by the window portion 441. As described above, by interposing the window portion 441 between the optical system 46 and the conveyor belt 11, it is possible to prevent fine powder generated from the tablet 9 from adhering to the optical system 46.

  In the manufacturing process of the tablet 9, every time the type of the tablet 9 to be manufactured changes, the tablet component manufactured last time remains in each part in the manufacturing apparatus. For this reason, in order to prevent the next tablet 9 from being contaminated, the manufacturing apparatus is cleaned over a great deal of time and effort. By providing the window portion 441 as in the present embodiment, it is possible to prevent chemical components from adhering to the precise optical system 46 and to prevent foreign substances from entering the tablet 9 from the optical system 46. Therefore, the trouble of cleaning this part can be reduced. Thereby, it can contribute to labor saving of a manufacturing process. Further, the internal pressure of the space where the optical system 46 is arranged can be made higher than the pressure of the space where the transport mechanism 10 for the tablet 9 is arranged via the window 441. If it does so, the tablet powder mixing risk to the optical system 46 from the clearance gap between the window parts 441 can further be reduced. Needless to say, the window portion 441 preferably has a structure with no gap using a sealant.

  The air blowing mechanism 45 is a mechanism for keeping the lower surface of the window portion 441 clean. As shown in FIG. 2, the air blowing mechanism 45 has a gas discharge nozzle 451 fixed to the lower surface of the housing 44. The gas discharge nozzle 451 is connected to an air supply source 453 via a pipe 452. An on-off valve 454 is provided on the path of the pipe 452. When the on-off valve 454 is opened, clean dry air is supplied from the air supply source 453 to the gas discharge nozzle 451 through the pipe 452. Then, clean dry air is blown from the gas discharge nozzle 451 toward the lower surface of the window portion 441 (the surface on the transport mechanism 10 side). The blown clean dry air forms an air layer along the lower surface of the window portion 441. Thereby, the fine powder generated from the tablet 9 is prevented from adhering to the lower surface of the window portion 441.

  Note that the control of the clean dry air is performed by the control unit 70. As the gas discharged from the blower mechanism 45, not only clean dry air but also other gases that do not affect the manufacture of the tablet 9 (for example, nitrogen) may be used. In addition, the blower mechanism 45 may always discharge a certain amount of gas, but depending on the manufacturing process of the tablet 9, the discharge amount may be changed every certain time or the gas discharge may be temporarily stopped. Also good. Moreover, in order to reduce the trouble at the time of apparatus cleaning, the isolation wall was arrange | positioned between the space where the tablet 9 is conveyed, and the space where the on-off valve 454 and the control part 70 are arrange | positioned, and both spaces were isolated from each other. A structure is preferred. If it does so, scattering of the tablet powder to the on-off valve 454 and the control part 70 can be prevented.

  Returning to FIG. The ink jet head 50 is a mechanism that ejects ink droplets toward the surface of the tablet 9 after exposure. The inkjet head 50 has a plurality of nozzles that eject ink droplets. The plurality of nozzles are arranged on the lower surface of the inkjet head 50 along the width direction. A control unit 70 to be described later ejects ink droplets from the nozzles of the inkjet head 50 so that an image is recorded in an appropriate direction on the surface of the tablet 9 according to the direction of each tablet 9. To do. Thereby, an image is recorded on the surface of the tablet 9 without stopping the conveyance of the tablet 9.

  As a method for ejecting ink from the nozzles, for example, a so-called piezo method is used in which a piezoelectric element that is a piezoelectric element is deformed by applying a voltage to pressurize and eject ink in the nozzle. However, you may use what is called a thermal system discharged by energizing a heater and heating and expanding the ink in a nozzle. Moreover, the edible ink manufactured with the raw material approved by the food hygiene law is used for the ink discharged from the inkjet head 50. FIG.

  Note that the exposure / printing unit 20 may include a plurality of inkjet heads 50. For example, four inkjet heads 50 that eject inks of different colors (for example, cyan, magenta, yellow, and black) may be arranged along the transport direction. In this way, a multicolor image can be recorded on the surface of the tablet 9 by superimposing single-color images formed by these colors. Therefore, the color used for the logo of the pharmaceutical company can be printed, which can contribute to strengthening the tablet brand.

  The fixing unit 60 is a mechanism for fixing the ink discharged from the inkjet head 50 to the tablet 9. The fixing unit 60 is disposed downstream of the inkjet head 50 in the transport direction. For the fixing unit 60, for example, a mechanism for performing infrared irradiation by a heater or a mechanism for blowing hot air toward the tablets 9 conveyed by the conveyance mechanism 10 is used. The ink attached to the surface of the tablet 9 is dried by infrared rays or hot air and fixed on the surface of the tablet 9.

  Infrared rays may be irradiated by any one or more of continuous irradiation, flash irradiation, and laser irradiation. When a unit that flashes infrared rays is used, heat is supplied only to a layer close to the surface of the tablet 9. For this reason, the ink adhering to the surface of the tablet 9 can be dried and the heating inside the tablet 9 can be suppressed. Thereby, it becomes possible to reduce the influence on a pharmaceutical ingredient. In addition, infrared rays may be irradiated with a laser or the like only on a region where ink is ejected using print data. In this way, the heat irradiation area can be reduced with respect to the tablet 9. Accordingly, it is possible to further reduce the influence of the tablet 9 on the pharmaceutical ingredients and the surface coating. The tablet 9 is held on the transport belt 11 in the process of passing through the fixing unit 60. Therefore, by using the rotation direction information acquired from the image acquisition unit 30 and the print information, it is possible to irradiate infrared rays only to an accurate print region. Of course, the infrared rays may be applied to all of the printed area, or may be applied to a part of the printed area (for example, only the outline of characters and symbols). By reducing the irradiation amount of infrared rays onto the tablet 9, it becomes possible to reduce the risk of alteration of the tablet components due to heat.

  The control unit 70 is means for controlling the operation of each unit in the tablet printing apparatus 1. FIG. 3 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. 3, the control unit 70 includes a computer having an arithmetic processing unit 71 such as a CPU, a memory 72 such as a RAM, and a storage unit 73 such as a hard disk drive. A computer program P for executing printing processing is installed in the storage unit 73.

  As shown in FIG. 3, the control unit 70 includes the transport mechanism 10, the image acquisition unit 30, the exposure unit 40 (including the laser oscillator 41, the spatial modulation element 42, and the air blowing mechanism 45), the inkjet head 50, And the fixing unit 60 are communicably connected. The control unit 70 temporarily reads the computer program P and data stored in the storage unit 73 into the memory 72, and the arithmetic processing unit 71 performs arithmetic processing based on the computer program P, whereby each of the above-described units is performed. Control the operation. Thereby, the printing process with respect to the some tablet 9 advances.

<1-2. About exposure and ink discharge processing>
As described above, the tablet printing apparatus 1 sequentially performs imaging, exposure, ink ejection, and fixing processes on the plurality of tablets 9 conveyed by the conveyance mechanism 10. Hereinafter, among these processes, the exposure and ink ejection processes will be described in more detail.

  FIG. 4 is a diagram showing a laser beam pattern 81 that the exposure unit 40 irradiates the surface of the tablet 9. The tablet printing apparatus 1 can print various characters and figures on the surface of the tablet 9 according to the input image data. In the present embodiment, as an example, the alphabet “ Assume that an “F” -shaped image is printed. The pattern 81 of the laser beam irradiated on the surface of the tablet 9 is a pattern having substantially the same shape and the same size as the printed image to be formed on the surface of the tablet 9.

  FIG. 5 is a diagram showing a range 82 in which the ink jet head 50 ejects ink to the surface of the tablet 9. As shown in FIG. 5, the range 82 in which ink is ejected onto the surface of the tablet 9 is an area that overlaps the laser beam pattern 81 irradiated on the surface of the tablet 9 and is slightly smaller than the laser beam pattern 81. This is a (thinned) area. As described above, in the tablet printing apparatus 1, after the laser beam is irradiated by the exposure unit 40, the ink jet head 50 ejects ink inside the outline of the pattern 81 formed by the laser beam.

  FIG. 6 is a diagram showing a change in the cross-sectional shape on the surface of the tablet 9. When the tablet 9 is conveyed below the exposure unit 40, the exposure unit 40 irradiates the surface of the tablet 9 with a laser beam having a pattern 81 shown in FIG. 4. Thereby, laser light is irradiated to the whole target area | region A which should form a printing image among the surfaces of the tablet 9. FIG. Here, the laser light of the present embodiment is ultraviolet light having a strongest central wavelength of 400 nm or less (the laser light includes a light component having a short wavelength and a light component having a long wavelength centered on the center wavelength). ). For this reason, as shown in the upper diagram in FIG. 6, in the target area A of the tablet 9, the organic matter is decomposed by receiving the laser beam, and is made hydrophilic and roughened. That is, fine irregularities are formed on the surface shape of the target area A. As a result, the surface roughness of the target area A out of the surface of the tablet 9 is larger (rougher) than the surface roughness of the other areas. In addition, the water-based ink is more easily adhered to the surface of the tablet 9 due to the hydrophilization.

  When the tablet 9 passes below the exposure unit 40 and reaches a position below the inkjet head 50, the inkjet head 50 ejects ink toward the surface of the tablet 9. At this time, as shown in FIG. 5, the inkjet head 50 ejects ink in a range 82 that is slightly smaller than the laser light pattern 81. Therefore, as shown in the middle diagram in FIG. 6, the region where the ink I is first attached on the surface of the tablet 9 is a region slightly smaller than the contour portion of the target region A.

  The roughened target area A has a smaller contact angle of the ink I than the other areas. Therefore, the ink I ejected into the target area A spreads from the ejected position to the periphery as shown in the lower diagram in FIG. However, the non-roughened area outside the target area A has a large contact angle of the ink I, so that the ink I hardly spreads outside the target area A. Therefore, the spreading of the ink I stops at the boundary between the target area A and the outer area. As a result, a printed image with a clear outline can be formed on the surface of the tablet 9.

<2. Second Embodiment>
Subsequently, a second embodiment of the present invention will be described.

  In the first embodiment, ultraviolet laser light is emitted from the laser oscillator 41, whereas in the second embodiment, infrared laser light is emitted from the laser oscillator 41. The center wavelength of the laser light is, for example, 700 nm or more. About the structure of the tablet printing apparatus 1, since it is equivalent to said 1st Embodiment, duplication description is abbreviate | omitted. Also in the second embodiment, the tablet printing apparatus 1 sequentially performs imaging, exposure, ink ejection, and fixing processes on the plurality of tablets 9 conveyed by the conveyance mechanism 10.

  In the present embodiment, the laser beam pattern 81 that the exposure unit 40 irradiates the surface of the tablet 9 is the same as in FIG. That is, the laser beam pattern 81 irradiated on the surface of the tablet 9 is a pattern having substantially the same shape and the same size as the printed image to be formed on the surface of the tablet 9. Further, a range 82 in which the ink jet head 50 ejects ink to the surface of the tablet 9 is the same as that in FIG. That is, the area 82 where the ink is ejected onto the surface of the tablet 9 is an area that overlaps the laser light pattern 81 irradiated on the surface of the tablet 9 and is slightly smaller (thinner) than the laser light pattern 81. A) Area.

  FIG. 7 is a diagram showing a change in the cross-sectional shape near the surface of the tablet 9 in the second embodiment. When the tablet 9 is conveyed below the exposure unit 40, the exposure unit 40 irradiates the surface of the tablet 9 with a laser beam having a pattern 81 shown in FIG. 4. Thereby, laser light is irradiated to the whole target area | region A which should form a printing image among the surfaces of the tablet 9. FIG. Here, the laser beam of the present embodiment is an infrared ray having a center wavelength of 700 nm or more. Therefore, as shown in the upper diagram in FIG. 7, the target area A of the tablet 9 is etched in a concave shape by receiving the laser beam. That is, the surface shape of the target area A is dug down as a whole. As a result, a recess is formed in the entire target area A.

  When the tablet 9 passes below the exposure unit 40 and reaches a position below the inkjet head 50, the inkjet head 50 ejects ink toward the surface of the tablet 9. At this time, as shown in FIG. 5, the inkjet head 50 ejects ink in a range 82 that is slightly smaller than the laser light pattern 81. Therefore, as shown in the middle diagram in FIG. 6, the region where the ink I is first attached on the surface of the tablet 9 is a region slightly smaller than the contour portion of the target region A.

  The ink I ejected into the target area A spreads from the ejected position to the periphery as shown in the lower diagram in FIG. However, in the present embodiment, the target area A after exposure is recessed more than other areas. For this reason, the ink I easily spreads in the target area A, but hardly spreads outside the target area A. Therefore, the spreading of the ink I stops at the boundary between the target area A and the outer area. As a result, a printed image with a clear outline can be formed on the surface of the tablet 9. Also, the ink is filled in the etched portion to improve the adhesion of the ink to the tablet 9, and the thickness of the ink layer is increased to prevent the ink layer from being peeled off or rubbed. Become stronger.

<3. Third Embodiment>
Subsequently, a third embodiment of the present invention will be described.

  FIG. 8 is a diagram illustrating a configuration of the tablet printing apparatus 1 according to the third embodiment. The tablet printing apparatus 1 of the present embodiment includes a first exposure unit 40a and a second exposure unit 40b that is located downstream of the first exposure unit 40a in the transport direction. Both the first exposure unit 40a and the second exposure unit 40b have the same configuration as the exposure unit 40 of the first embodiment described above. However, in the first embodiment described above, the laser light of the ultraviolet ray is emitted from the laser oscillator 41, whereas the first exposure unit 40a and the second exposure unit 40b of the present embodiment are both laser oscillators 41. Infrared laser light is emitted from. The center wavelength of the laser light is, for example, 700 nm or more.

  Since the configuration of the tablet printing apparatus 1 other than the exposure unit is the same as that of the first embodiment, a duplicate description is omitted. Also in the third embodiment, the tablet printing apparatus 1 sequentially performs imaging, exposure, ink ejection, and fixing processes on the plurality of tablets 9 conveyed by the conveyance mechanism 10.

  The pattern 81 of the laser beam that the first exposure unit 40a irradiates the surface of the tablet 9 is the same as that in FIG. That is, the pattern 81 of the laser beam that the first exposure unit 40a irradiates the surface of the tablet 9 is substantially the same shape and the same size as the print image to be formed on the surface of the tablet 9. FIG. 9 is a diagram showing a laser beam pattern 83 that the second exposure unit 40 b irradiates the surface of the tablet 9. As shown in FIG. 9, the laser beam pattern 83 that the second exposure unit 40 b irradiates the surface of the tablet 9 overlaps with the print image to be formed on the surface of the tablet 9 and the print to be formed on the surface of the tablet 9. It is an annular pattern along the contour of the image.

  Further, a range 82 in which the ink jet head 50 ejects ink to the surface of the tablet 9 is the same as that in FIG. That is, the range 82 in which the ink is ejected onto the surface of the tablet 9 is an area inside the annular pattern 83 that is the irradiation range of the laser light of the second exposure unit 40b.

  FIG. 10 is a diagram showing a change in cross-sectional shape near the surface of the tablet 9 in the third embodiment. When the tablet 9 is conveyed below the first exposure unit 40a, the first exposure unit 40a irradiates the surface of the tablet 9 with a laser beam of a pattern 81 shown in FIG. Thereby, laser light is irradiated to the whole target area | region A which should form a printing image among the surfaces of the tablet 9. FIG. Here, the laser beam of the present embodiment is an infrared ray having a center wavelength of 700 nm or more. Therefore, as shown in the uppermost diagram in FIG. 10, the target area A of the tablet 9 is etched in a concave shape by receiving the laser beam. That is, the surface shape of the target area A is dug down as a whole. As a result, a recess is formed in the entire target area A.

  When the tablet 9 passes below the first exposure part 40a and reaches the lower position of the second exposure part 40b, the second exposure part 40b applies the laser beam of the pattern 83 shown in FIG. Irradiate. Thereby, only the outline A1 of the target area A in the surface of the tablet 9 is additionally irradiated with the laser light. Therefore, the irradiation amount per unit area of infrared rays for the contour portion A1 is larger than the irradiation amount per unit area of infrared rays for the inner portion A2 surrounded by the contour portion A1. As a result, as shown in the second step from the top of FIG. 10, the contour portion A1 is etched deeper than the inner portion A2.

  When the tablet 9 passes under the second exposure unit 40 b and reaches the position below the inkjet head 50, the inkjet head 50 ejects ink toward the surface of the tablet 9. At this time, as shown in FIG. 5, the ink jet head 50 ejects ink inside the laser light irradiation range of the second exposure unit 40b. Therefore, as shown in the third drawing from the top in FIG. 10, the ink I adheres to the inner portion A <b> 2 surrounded by the contour portion A <b> 1 in the target area A.

  The ink I ejected to the inner side spreads from the ejected position to the periphery as shown in the lowermost diagram of FIG. However, in the present embodiment, the target area A after exposure is recessed more than other areas. Further, the contour part A1 of the target area A is further recessed than the inner part A2. Therefore, the ink I easily spreads from the inner portion A2 to the contour portion A1, but hardly spreads to the outer side of the contour portion A1. Therefore, the spreading of the ink I stops at the boundary between the target area A and the outer area. As a result, a printed image with a clear outline can be formed on the surface of the tablet 9.

  In the present embodiment, after the first exposure unit 40a exposes both the contour part A1 and the inner part A2, the second exposure unit 40b exposes only the contour part A1, but this exposure order is reversed. There may be. That is, after only the contour portion A1 is exposed, both the contour portion A1 and the inner portion A2 may be exposed.

  Moreover, the irradiation amount per unit area of the laser beam to the contour portion A1 is equal to the irradiation amount per unit area of the laser beam to the inner portion A2 in a single exposure unit without using the plurality of exposure units 40a and 40b. You may control to become more than quantity. Specifically, for example, a plurality of mirror arrays arranged in the transport direction using a spatial modulation element 42 such as a DMD in which fine mirrors are two-dimensionally arranged, and laser light is applied to the entire target area A. And the mirror array that irradiates only the contour portion A1 with the laser light.

<4. Fourth Embodiment>
Subsequently, a fourth embodiment of the present invention will be described.

  The tablet printing device 1 of the fourth embodiment has a configuration equivalent to that of the tablet printing device 1 of the third embodiment shown in FIG. In other words, the tablet printing apparatus 1 according to the fourth embodiment includes a first exposure unit 40a and a second exposure unit 40b located on the downstream side in the transport direction with respect to the first exposure unit 40a. The first exposure unit 40 a and the second exposure unit 40 b both emit infrared laser light from the laser oscillator 41. The center wavelength of the laser light is, for example, 700 nm or more.

  Since the configuration of the tablet printing apparatus 1 other than the exposure unit is the same as that of the first embodiment, a duplicate description is omitted. Also in the fourth embodiment, the tablet printing apparatus 1 sequentially performs imaging, exposure, ink ejection, and fixing processes on the plurality of tablets 9 conveyed by the conveyance mechanism 10.

  In the present embodiment, the laser light pattern 81 that the first exposure unit 40a irradiates the surface of the tablet 9 is the same as that shown in FIG. That is, the pattern 81 of the laser beam that the first exposure unit 40a irradiates the surface of the tablet 9 is substantially the same shape and the same size as the print image to be formed on the surface of the tablet 9. FIG. 11 is a diagram showing a laser beam pattern 84 that the second exposure unit 40 b irradiates the surface of the tablet 9. As shown in FIG. 11, the laser light pattern 84 that the second exposure unit 40 b irradiates the surface of the tablet 9 overlaps with the print image to be formed on the surface of the tablet 9 and should be formed on the surface of the tablet 9. An annular pattern 841 along the outline of the printed image and a plurality of isolated patterns 842 regularly arranged inside the annular pattern 841 are included.

  Further, a range 82 in which the ink jet head 50 ejects ink to the surface of the tablet 9 is the same as that in FIG. That is, a range 82 in which ink is ejected onto the surface of the tablet 9 overlaps the plurality of isolated patterns 842 described above and is an area inside the annular pattern 841 described above.

  FIG. 12 is a diagram showing a change in the cross-sectional shape near the surface of the tablet 9 in the fourth embodiment. When the tablet 9 is conveyed below the first exposure unit 40a, the first exposure unit 40a irradiates the surface of the tablet 9 with a laser beam of a pattern 81 shown in FIG. Thereby, laser light is irradiated to the whole target area | region A which should form a printing image among the surfaces of the tablet 9. FIG. Here, the laser beam of the present embodiment is an infrared ray having a center wavelength of 700 nm or more. Therefore, as shown in the uppermost diagram in FIG. 12, the target area A of the tablet 9 is etched in a concave shape by receiving the laser beam. That is, the surface shape of the target area A is dug down as a whole. As a result, a recess is formed in the entire target area A.

  When the tablet 9 passes below the first exposure part 40a and reaches the lower position of the second exposure part 40b, the second exposure part 40b applies the laser beam of the pattern 84 shown in FIG. Irradiate. Thereby, laser light is additionally irradiated to both the contour part A1 of the target area A and the plurality of isolated parts A3 located inside the contour part A1 in the surface of the tablet 9. Therefore, in the target area A, the irradiation amount per unit area of the infrared rays for the contour portion A1 and the plurality of isolated portions A3 is larger than the irradiation amount per unit time of the infrared rays for other portions of the target region A. As a result, the contour portion A1 and the plurality of isolated portions A3 are etched deeper than the other portions of the target area A as shown in the second diagram from the top in FIG.

  When the tablet 9 passes under the second exposure unit 40 b and reaches the position below the inkjet head 50, the inkjet head 50 ejects ink toward the surface of the tablet 9. As a result, as shown in the third drawing from the top in FIG. 12, the ink adheres to the inner side of the target area A surrounded by the outline A1.

  The ink ejected to the inner portion A2 spreads from the ejected position to the periphery as shown in the lowermost diagram of FIG. However, in the present embodiment, the target area A after exposure is recessed more than other areas. For this reason, the ink is difficult to spread to the outside of the contour portion A1. Accordingly, the ink spreading stops at the boundary between the target area A and the outer area. As a result, a printed image with a clear outline can be formed on the surface of the tablet 9.

  In the present embodiment, a plurality of isolated portions A3 (first regions) and portions shallower than the isolated portions A3 (second regions) are alternately arranged inside the contour portion A1. Thereby, the flow of ink is further suppressed. Therefore, it is further suppressed that the ink spreads outside the target area A. In particular, when the target area A of the tablet 9 is an inclined surface with respect to the horizontal plane, it is necessary to suppress ink flow due to gravity. In such a case, this embodiment is particularly useful.

  In the present embodiment, after the first exposure unit 40a exposes the entire target area A, the second exposure unit 40b exposes the contour portion A1 and the plurality of isolated portions A3. However, the order of this exposure is reversed. It may be. That is, the entire target area A may be exposed after the contour part A1 and the plurality of isolated parts A3 are exposed.

  Moreover, the irradiation amount per unit area of the laser light to the contour portion A1 and the plurality of isolated portions A3 can be changed to the laser light to other portions in a single exposure portion without using the plurality of exposure portions 40a and 40b. You may control so that it may be larger than the irradiation amount per unit area. Specifically, for example, a plurality of mirror arrays arranged in the transport direction using a spatial modulation element 42 such as a DMD in which fine mirrors are two-dimensionally arranged, and laser light is applied to the entire target area A. And the mirror row that irradiates only the contour portion A1 and the plurality of isolated portions A3 with laser light.

  Moreover, you may make it not irradiate infrared rays to the 2nd area | region mentioned above. In that case, the first exposure unit 40a may be omitted, and only the exposure of the contour portion A1 and the plurality of isolated portions A3 by the second exposure unit 40a may be performed.

<5. Modification>
As mentioned above, although main embodiment of this invention was described, this invention is not limited to said embodiment.

  In each of the above embodiments, either one of ultraviolet light and infrared light is irradiated from the exposure unit 40, but ultraviolet laser light and infrared laser light may be used in combination. For example, in the configuration of FIG. 8, infrared laser light may be irradiated from the first exposure unit 40a, and ultraviolet laser light may be irradiated from the second exposure unit 40b. By doing so, the effect of preventing the ink from spreading by etching, the effect of preventing the ink from spreading by utilizing the difference in the contact angle of the ink caused by the roughening, and the effect of improving the adhesion of the ink And can be obtained. Therefore, it is possible to further suppress the ink ejected from the inkjet head 50 from spreading outside the target area A.

  In the above embodiment, the reflective spatial modulation element 42 is used to form the laser beam into a desired pattern. However, a transmissive crystal optical element is used instead of the spatial modulation element 42. Also good. Since a transmissive crystal optical element generally has high durability, it is possible to use a laser beam with higher intensity or to irradiate the laser beam for a long time by using the crystal optical element. . As a result, it is possible to reduce the risk of the apparatus being stopped due to a defect in the optical element of the exposure unit 40 in the tablet manufacturing process. The exposure part 40 should just be what can irradiate the tablet 9, shape | molding the ultraviolet-ray or infrared rays radiate | emitted from the light source in the designated pattern.

  Moreover, in said embodiment, although the exposure part 40 irradiated the laser beam to the surface of the tablet 9, the light irradiated to the tablet 9 does not necessarily need to be a laser beam. The light source of the exposure part 40 should just be a light source which can irradiate an ultraviolet-ray or infrared rays.

  In the above embodiment, the laser light irradiation pattern is the same as or narrower than the print area. Of course, the exposure unit 40 may irradiate the laser light to an area wider than the print area. When the performance of inkjet printing is improved by modifying the surface of the tablet 9 as in the case of ultraviolet irradiation, the printing performance can be improved even when the conventional aqueous ink is water-repellent on the tablet surface and cannot be printed. By performing laser irradiation on a region wider than the printing region, clear printing can be realized even if the alignment accuracy between the laser exposure position and the inkjet printing position is somewhat low. Therefore, the tablet 9 can be conveyed at higher speed, and the positional accuracy variation of the conveyance 11 belt can be absorbed. As a result, it is possible to employ a transport system that sacrifices some accuracy, and to contribute to a reduction in apparatus cost.

  Moreover, about the detailed structure of the tablet printing apparatus 1, you may differ from each figure of this application. Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Tablet printer 9 Tablet 10 Conveyance mechanism 11 Conveyor belt 12 Adsorption hole 20 Exposure and printing part 30 Image acquisition part 40 Exposure part 40a 1st exposure part 40b 2nd exposure part 41 Laser oscillator 42 Spatial modulation element 43 Condensing lens 44 Housing 45 Blowing mechanism 46 Optical system 50 Inkjet head 60 Fixing part 70 Control part 441 Window part A Target area A1 Contour part A2 Inner part A3 Isolated part

Claims (11)

A tablet printing apparatus comprising a transport mechanism for transporting while holding a tablet, and printing on the surface of the tablet,
An exposure unit that irradiates at least one of ultraviolet rays and infrared rays toward the surface of the tablet conveyed by the conveyance mechanism;
An inkjet head that ejects ink toward the surface of the tablet that has passed through the exposed portion;
A tablet printing apparatus. The tablet printing apparatus according to claim 1,
The said exposure part is a tablet printing apparatus which irradiates at least one of an ultraviolet-ray and infrared rays to the area | region wider than the target area | region which should form a printing image. The tablet printing apparatus according to claim 1,
The said exposure part is a tablet printing apparatus which irradiates at least one of an ultraviolet-ray and infrared rays on the surface of a tablet via a spatial modulation element or a crystal optical element. The tablet printing apparatus according to claim 1,
The exposure unit is
A light source that emits at least one of ultraviolet and infrared;
An optical system for guiding the light emitted from the light source to the tablet;
A housing containing at least a part of the optical system and having a light-transmitting window positioned between the optical system and the transport mechanism;
A tablet printing device. The tablet printing apparatus according to claim 4,
The exposure unit is
The tablet printing apparatus which further has a ventilation mechanism which blows gas on the surface by the side of the said conveyance mechanism of the said window part. A tablet printing apparatus according to any one of claims 1 to 5, wherein
The exposure unit is a tablet printing apparatus that irradiates at least one of ultraviolet and infrared laser light. A tablet printing apparatus according to any one of claims 1 to 5, wherein
It further has a fixing unit arranged on the downstream side in the transport direction from the inkjet head,
The fixing unit is a tablet printing apparatus that irradiates infrared rays by one or more methods of continuous irradiation, flash irradiation, and laser irradiation toward an irradiation region including at least a part of a printing region on the surface of the tablet. A tablet printing method for printing on the surface of a tablet while transporting the tablet,
a) irradiating at least one of ultraviolet rays and infrared rays toward the surface of the tablet;
b) after step a), discharging ink toward the surface of the tablet;
A tablet printing method comprising: A tablet printing method according to claim 8,
In the step a), the tablet printing method is characterized in that at least one of ultraviolet rays and infrared rays is irradiated to a region wider than a target region where a print image is to be formed. A tablet printing method according to any one of claims 8 or 9, wherein
In the step a), a tablet printing method in which at least one laser beam of ultraviolet rays and infrared rays is irradiated. A tablet printing method according to any one of claims 8 to 10, wherein
After the step b), a step of irradiating infrared rays by one or more methods of continuous irradiation, flash irradiation, and laser irradiation toward an irradiation region including at least a part of the printing region on the surface of the tablet. Furthermore, the tablet printing method which has.

Images