Tablet printing device and tablet printing method

Abstract

To enable efficient printing on tablets.SOLUTION: A tablet printing device includes: a conveying device which has a conveying belt and a pulley that can rotate the conveying belt, and which adsorbs and holds tablets on the conveying belt and conveys them; an inkjet head that performs printing on the tablets conveyed by the conveying device; and a cleaning device that cleans the conveying belt. The cleaning device includes: a box that covers a part of the conveying belt; a gas blowing device provided inside the box and configured to blow gas toward the conveying device; and a gas suction section that sucks and removes a foreign matter adhering to the conveying device and removed by the gas blowing device. The gas blowing device blows the gas onto an outer surface of the conveying belt on an outer periphery of the pulley.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a tablet printing device and a tablet printing method. [Background technology]

[0002] Currently, tablet printing devices have been developed that use inkjet heads to print various types of information, such as identification information, onto tablets on a conveyor belt. A conveyor belt is an example of a conveyor device. In tablet printing devices, powder from the tablets typically adheres to the conveyor belt, gradually contaminating it. This can lead to false detections by the detection unit (e.g., laser displacement meter, camera) that detects the tablets. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-58220 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a tablet printing device and a tablet printing method that can efficiently print on tablets. [Means for solving the problem]

[0005] A tablet printing device according to an embodiment of the present invention comprises a conveying device that includes a conveying belt and a pulley that can rotate the conveying belt, and that adsorbs and holds tablets on the conveying belt for conveying, an inkjet head that prints on the tablets being conveyed by the conveying device, and a cleaning device that cleans the conveying belt, wherein the cleaning device comprises a box that covers part of the conveying belt, a gas blowing device that is provided within the box and blows gas toward the conveying device, and a gas suction unit that sucks and removes foreign matter that has adhered to the conveying device and been removed by the gas blowing device, and wherein the gas blowing device blows the gas against the outer surface of the conveying belt around the outer periphery of the pulley.

[0006] In a tablet printing method according to an embodiment of the present invention, a conveying device including a conveying belt and a pulley capable of rotating the conveying belt conveys tablets, an inkjet head prints on the tablets being conveyed by the conveying device, a gas spraying device sprays gas onto the outer surface of the conveying belt around the outer periphery of the pulley of the conveying device, and a gas suction section sucks and removes foreign matter adhering to the conveying device that has been removed by the gas sprayed by the gas spraying device. [Effects of the Invention]

[0007] According to an embodiment of the present invention, printing can be performed on tablets efficiently. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the configuration of a tablet printing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a plan view illustrating an example of the configuration of a first printing apparatus according to the first embodiment. [Figure 3] 3A and 3B are diagrams illustrating an example of the configuration of a cover according to the first embodiment. [Figure 4] 1 is a diagram illustrating an example of the configuration of a cleaning device according to a first embodiment. [Figure 5] 1 is a plan view illustrating an example of the configuration of a cleaning device according to a first embodiment. [Figure 6]5 is a flowchart showing the flow of a cleaning process according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment The first embodiment will be described with reference to FIGS.

[0010] (Basic configuration) As shown in Fig. 1, the tablet printing apparatus 1 according to the first embodiment includes a supplying device 10, a first printing device 20, a second printing device 30, a collecting device 40, and a control device 50. The first printing device 20 and the second printing device 30 basically have the same structure. Note that, in the first embodiment, "upper" and "lower" refer to upper and lower in the vertical direction.

[0011] The supply device 10 has a hopper 11, an aligning and conveying device (aligning feeder) 12, and an intermediary conveying device (transfer feeder) 13. This supply device 10 is configured to be able to supply tablets T to be printed to the first printing device 20, and is positioned at one end side of the first printing device 20, i.e., upstream in the conveying direction A1 of the tablets T. The hopper 11 stores a large number of tablets T and sequentially supplies the tablets T to the aligning and conveying device 12. The aligning and conveying device 12 aligns the supplied tablets T in two rows and conveys them toward the intermediary conveying device 13. The intermediary conveying device 13 sequentially sucks and holds each of the tablets T arranged in two rows on the aligning and conveying device 12 from above, and transports the held tablets T in two rows to the first printing device 20 and hands them over to the first printing device 20. When the tablets T are sucked and held from above by the intermediary conveying device 13, they are held in a state against gravity. For this reason, the suction force of the relay conveying device 13 is set to a suction force that will not cause the tablets T to drop while being conveyed, and is set stronger than that of a conveying device that supports the tablets T from below and holds them by suction. Such a supplying device 10 is electrically connected to the control device 50, and its drive is controlled by the control device 50. As the aligning conveying device 12 and the relay conveying device 13, for example, a belt conveying mechanism can be used.

[0012] The relay conveying device 13 has a conveyor belt 13a, a drive pulley (pulley body) 13b, a driven pulley (pulley body) 13c, a motor (drive unit) 13d, and a suction chamber (suction unit) 13e. The conveyor belt 13a has at least a portion through which gas passes, i.e., is an endless belt with gas permeability (including belts that allow gas to pass through holes provided in the belt and belts made of mesh material), and is stretched over the drive pulley 13b and the driven pulley 13c. Preferably, it is a ladder-shaped belt with connecting parts connecting two thin belts provided at predetermined intervals. Both ends of the tablet T are supported by the conveyor belt 13a, and suction force is applied to many parts of the surface of the tablet T, causing it to be adsorbed and held. The drive pulley 13b and the driven pulley 13c are rotatably provided in the device main body, and the drive pulley 13b is connected to the motor 13d. The motor 13d is electrically connected to the control device 50, and its drive is controlled by the control device 50. In this relay conveying device 13, the conveying belt 13a is rotated together with the driven pulley 13c by the rotation of the drive pulley 13b by the motor 13d, and the tablets T from the aligning and conveying device 12 are sucked and held on the underside of the conveying belt 13a by the suction action of the suction chamber 13e, and the suction-held tablets T are conveyed in the conveying direction A1 and delivered to the first printing device 20 at a position where the suction action of the suction chamber 13e no longer works. The "conveying surface" of the conveying belt 13a refers to the plane between the symbols a and b in Figure 1.

[0013] A gas-permeable rectifying plate 14 is provided below the relay conveying device 13. This rectifying plate 14 is spaced a predetermined distance from the conveying path along which the tablets T are conveyed by the relay conveying device 13, i.e., the conveying surface of the conveyor belt 13a, and is horizontally disposed so as to face the conveying surface. The predetermined distance is longer than the thickness of the tablets T (e.g., 2 to 4 mm) and is within a range (e.g., 5 to 12 mm) that can regulate the airflow generated by suction by the suction chamber 13e of the relay conveying device 13. The rectifying plate 14 is provided at a position through which the airflow generated by suction by the suction chamber 13e passes, and regulates the airflow generated below and around the conveying surface of the conveyor belt 13a. This rectifying plate 14 is provided so as to face the conveying path along which the tablets T are sucked from above and conveyed in the relay conveying device 13, and also functions as a tray to receive tablets T that have fallen from the conveying surface of the conveyor belt 13a. That is, the rectifying plate 14 has a receiving surface M1 that receives the fallen tablets T.

[0014] The length of the rectifying plate 14 in the width direction (the direction horizontally perpendicular to the conveying direction A1) is equal to or greater than the length of the conveyor belt 13a in the width direction (the direction horizontally perpendicular to the conveying direction A1). The length of the rectifying plate 14 in the conveying direction A1 is shorter than the length of the relay conveying device 13 in the conveying direction A1, but is not limited to this. The rectifying plate 14 can be made of various plate materials with multiple through holes, such as a mesh plate, a punched board with multiple round holes, or a board with multiple slit holes. The rectifying plate 14 can be made of metal such as stainless steel (SUS), but is not limited to this material. Any material that complies with the Food Sanitation Act, such as aluminum or resin, can also be used.

[0015] As described above, the conveyor belt 13a of the relay conveyor device 13 is provided with a stronger suction force than a conveyor device of the type that supports and holds the tablets T by suction. The conveyor belt 13a is the ladder-shaped belt described above, and holds most of the surface of the tablets T in a suctioned state. This strong suction force acts on the surface of the tablets T that comes into contact with the conveyor belt 13a, and most of the powder of the tablets T that adheres to the surface that comes into contact with the conveyor belt 13a is sucked and removed here.

[0016] The first printing device 20 includes a conveying device 21 , a detecting device 22 , a first imaging device 23 , a print head device 24 , a second imaging device 25 , a drying device 26 , and a cleaning device 80 .

[0017] The conveying device 21 includes a conveying belt 21a, a driving pulley (pulley body) 21b, multiple (three in the example of FIG. 1) driven pulleys (pulley bodies) 21c, a motor (driving unit) 21d, a position detector 21e, and a suction chamber (suction unit) 21f. The conveying belt 21a is an endless belt and is stretched over the driving pulley 21b and each driven pulley 21c. The driving pulley 21b and each driven pulley 21c are rotatably mounted on the device body, and the driving pulley 21b is connected to the motor 21d. The motor 21d is electrically connected to the control device 50, and its driving is controlled by the control device 50. The position detector 21e is a device such as an encoder and is attached to the motor 21d. The position detector 21e is electrically connected to the control device 50 and transmits a detection signal to the control device 50. Based on the detection signal, the control device 50 can obtain information such as the position, speed, and movement amount of the conveying belt 21a. In this conveying device 21, the conveying belt 21a is rotated together with each driven pulley 21c by the rotation of the drive pulley 21b by the motor 21d, and the tablets T on the conveying belt 21a are conveyed in the conveying direction A1. In this specification, the "upper conveying surface" of the conveying belt 21a refers to the plane between the symbols c and d in FIG. 1, the "right conveying surface" of the conveying belt 21a refers to the curved surface between the symbols d and e in FIG. 1, and the "lower conveying surface" of the conveying belt 21a refers to the plane between the symbols e and f in FIG. 1. In other words, on the lower conveying surface of the conveying belt 21a, the tablets T are conveyed along the conveying direction A2.

[0018] As shown in FIG. 2, a plurality of circular suction holes 21g are formed on the surface of the conveyor belt 21a. Each of these suction holes 21g is a through-hole that adsorbs the tablet T and is arranged in two parallel rows along the conveying direction A1 to form two conveying paths. Each suction hole 21g is connected to the inside of the suction chamber 21f via a suction path formed in the suction chamber 21f, and suction force can be obtained by the suction chamber 21f. A suction device (not shown), such as a pump, is connected to the suction chamber 21f via a suction pipe, and the inside of the suction chamber 21f is depressurized by operation of the suction device. For example, the suction pipe is connected to approximately the center of the side surface (plane parallel to the conveying direction A1) of the suction chamber 21f. The suction device is electrically connected to the control device 50, and its operation is controlled by the control device 50.

[0019] The interior of the suction chamber 21f is divided into multiple areas, and the suction force acting on the suction holes 21g is controlled to be different in each area. For example, the conveyor belt 21a is divided into three areas: the upper conveying surface (between symbols c and d), the right conveying surface (between symbols d and e), and the lower conveying surface (between symbols e and f). The right conveying surface is controlled to have the strongest suction force, the lower conveying surface the next strongest, and the upper conveying surface the weakest. First, the right conveying surface requires a suction force strong enough to prevent tablets T from being shaken off by the centrifugal force generated by the rotation of the drive pulley 21b, so a stronger suction force is set than in the other two areas. Next, the lower conveying surface is set to have a suction force that prevents tablets T from falling during conveyance, because tablets T are suction-held in a direction against gravity. This suction force is set to be stronger than that of the upper conveying surface, which supports and suction-holds tablets T from below. Since printing is performed on the upper conveying surface by a print head device 24 having an inkjet head 24a (described later), a weaker suction force is set on the upper conveying surface compared to other areas to prevent the nozzles 24b (described later) of the inkjet head 24a from drying out due to the suction force.

[0020] The strength of the suction force may be set by providing independent intake pipes connected to each area and adjusting the opening of valves provided in the intake pipes. Alternatively, a baffle may be provided between the suction hole 21g and the suction chamber 21f to control the suction force so that it is appropriately reduced.

[0021] The detection device 22 has a plurality of detection units 22a (two in the example of FIG. 2). The detection units 22a are arranged one by one for each conveyance path of the tablets T downstream in the conveyance direction A1 from the position on the conveyor belt 21a where the tablets T are supplied by the supply device 10, in a direction intersecting (for example, perpendicular to) the conveyance direction A1 in the horizontal plane, and are provided above the upper conveyance surface of the conveyor belt 21a. The detection units 22a detect the position of the tablets T on the conveyor belt 21a (position in the conveyance direction A1) by projecting and receiving laser light, and function as trigger sensors for each device located downstream. Various laser sensors such as reflective laser sensors can be used as the detection units 22a. Each detection unit 22a is electrically connected to the control device 50 and transmits a detection signal to the control device 50.

[0022] The first imaging device 23 has a plurality of imaging units 23a (two in the example of FIG. 2). The imaging units 23a are arranged downstream in the conveying direction A1 from the position where the detection device 22 is provided, one for each conveying path of the tablets T in a direction intersecting (for example, perpendicular to) the conveying direction A1 in the horizontal plane, and are provided above the upper conveying surface of the conveyor belt 21a. Based on the position information of the tablet T described above, the imaging units 23a capture images when the tablet T arrives directly below the imaging units 23a, obtain an image including the top surface of the tablet T (first image), and transmit the obtained image to the control device 50. The imaging units 23a can be various cameras having imaging elements such as a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor). Each imaging unit 23a is electrically connected to the control device 50, and its operation is controlled by the control device 50. Incidentally, illumination for imaging is also provided as necessary.

[0023] The print head device 24 has inkjet heads 24a (two in the example of FIG. 2). The inkjet heads 24a are arranged downstream in the conveying direction A1 from the position where the first imaging device 23 is provided, in a direction intersecting (e.g., perpendicular to) the conveying direction A1 in a horizontal plane, one for each conveying path of the tablets T, and are provided above the upper conveying surface of the conveyor belt 21a. Each inkjet head 24a has, for example, several hundred to several thousand nozzles 24b (only four are illustrated in the example of FIG. 2), and ink is ejected individually from each nozzle 24b. The inkjet head 24a is provided so that the direction in which the nozzles 24b are aligned intersects (e.g., perpendicular to) the conveying direction A1 in a horizontal plane. Various inkjet print heads having driving elements such as piezoelectric elements, heating elements, or magnetostrictive elements can be used as the inkjet heads 24a. Each inkjet head 24a is electrically connected to a control device 50, and its driving is controlled by the control device 50.

[0024] The second imaging device 25 has a plurality of imaging units 25a (two in the example of FIG. 2). The imaging units 25a are arranged downstream in the conveying direction A1 from the position where the print head device 24 is provided, one for each conveying path of the tablets T in a direction intersecting (for example, perpendicular to) the conveying direction A1 in the horizontal plane, and are provided above the upper conveying surface of the conveyor belt 21a. Based on the position information of the tablet T described above, the imaging units 25a capture images when the tablet T arrives directly below the imaging units 25a, obtain an image (second image) including the upper surface of the tablet T, and transmit the obtained image to the control device 50. As with the imaging unit 23a described above, various cameras having imaging elements such as CCD or CMOS can be used as the imaging units 25a. Each imaging unit 25a is electrically connected to the control device 50, and its driving is controlled by the control device 50. Incidentally, illumination for imaging is also provided as necessary.

[0025] As shown in FIGS. 1 to 3, the detection device 22, first imaging device 23, print head device 24, and second imaging device 25 are covered by a cover 60. This cover 60 is a housing that houses the detection device 22 (two detection units 22a), the first imaging device 23 (two imaging units 23a), the print head device 24 (two inkjet heads 24a), and the second imaging device 25 (two imaging units 25a). The cover 60 is provided above the upper conveying surface of the conveyor belt 21a, separated by a predetermined distance (e.g., 5 to 12 mm) from the upper conveying surface of the conveyor belt 21a in accordance with the thickness (e.g., 2 to 8 mm) of the tablets T so that the lower surface of the cover 60 does not come into contact with the tablets T conveyed by the conveyor belt 21a. Note that, for example, when illumination for imaging (e.g., line illumination or ring illumination) is provided, the illumination may also be provided within the cover 60.

[0026] 3, two through holes 60a are formed on the underside of the cover 60 in a direction perpendicular to the conveying direction A1 in a horizontal plane so that each detection unit 22a in the cover 60 can detect each tablet T on the conveyor belt 21a, and two through holes 60b are formed in the same direction as the direction in which the through holes 60a are arranged so that each imaging unit 23a in the cover 60 can image each tablet T on the conveyor belt 21a. Furthermore, two through holes 60c are formed on the underside of the cover 60 in the same direction as the direction in which the through holes 60a are arranged so that each inkjet head 24a in the cover 60 can print on each tablet T on the conveyor belt 21a, and two through holes 60d are formed in the same direction as the direction in which the through holes 60a are arranged so that each imaging unit 25a in the cover 60 can image each tablet T on the conveyor belt 21a.

[0027] The through-holes 60a, 60b, and 60d are closed by light-transmitting members 61 and 62, such as transparent glass. Each of the light-transmitting members 61 and 62 is provided, for example, on the bottom surface inside the cover 60. Each of the through-holes 60c is closed by inserting the inkjet head 24a into the through-hole 60c via a sealing member 63, such as silicone. In this manner, the cover 60 is formed in a sealed state, and the inside of the cover 60 is maintained, for example, at a positive pressure. Note that the light-transmitting members 61 and 62 may be provided by being fitted into the through-holes 60a, 60b, and 60d, or may be provided on the outer surface of the cover 60, as long as they can close the through-holes 60a, 60b, and 60d.

[0028] (Configuration of cleaning device 80) Next, the configuration of the cleaning device 80 will be described with reference to Figures 1, 4, and 5. The cleaning device 80 is provided, for example, below the transport device 21. The cleaning device 80 includes a box 81, a high-pressure gas injection nozzle 82 (gas spraying device), a first diffusion prevention plate 83, a second diffusion prevention plate 84, and a gas suction port 85 (gas suction section). 1 and 4, the box 81 has a bottom surface B1 that covers a portion of the lower part of the conveying device 21, and the widthwise length of the bottom surface B1 is longer than the widthwise length of the conveying belt 21a. The box 81 is configured to cover a portion of the conveying device 21 with the bottom surface B1 and three side surfaces that rise from the bottom surface B1. More specifically, the box 81 has the bottom surface B1 that covers a portion of the lower conveying surface of the conveying device 21, a pair of side surfaces that cover a portion of the side surfaces of the conveying device 21 that extend along the conveying direction A2, and one side surface that covers a portion of the right-hand conveying surface of the conveying device 21 (between symbols d and e).

[0029] As shown in Figures 4 and 5, the box 81 is provided with a high-pressure gas injection nozzle 82, a first diffusion prevention plate 83, and a second diffusion prevention plate 84. The bottom surface B1 can be made of various plate materials with multiple through holes, such as a mesh plate, a punched board with multiple round holes, or a board with multiple slit holes, and is gas permeable. The bottom surface B1 is spaced a predetermined distance (longer than the thickness of the tablet and within a range that can regulate the airflow generated by suction by the suction chamber 21f of the conveying device 21) from the conveying path along which the tablets T are conveyed by the conveying device 21, i.e., the lower conveying surface of the conveying device 21, and is horizontally positioned opposite the conveying surface. A gas suction port 85 is provided at a predetermined position upstream in the conveying direction A2. The bottom surface B1 functions as a straightening plate that regulates the airflow generated by the suction chamber 21f, and also functions as a tray to receive the tablets T when they fall from the lower conveying surface of the conveying belt 21a of the conveying device 21.

[0030] Two high-pressure gas injection nozzles 82 (82A, 82B) are provided in the box 81, corresponding to the two rows of conveying paths. High-pressure gas is injected from each of the high-pressure gas injection nozzles 82A, 82B toward the right conveying surface of the conveyor belt 21a. The width of the injection openings of the high-pressure gas injection nozzles 82A, 82B is preferably longer than the width of the tablets T conveyed on the conveyor belt 21a. This allows the gas to be injected into an area where tablet T powder may adhere. The gas supplied from the high-pressure corpse injection nozzles 82A, 82B collides with the outer surface of the conveyor belt 21a and spreads and flows radially on the outer surface of the conveyor belt 21a. The high-pressure gas injection nozzles 82 are connected to a gas supply source (not shown) via valves 821 (821a, 821b), and their operation is controlled by the control device 50. The gas supplied from the high-pressure gas injection nozzles 82A and 82B is, for example, clean dry air, and the gas supply source is a utility facility (not shown) provided in the factory where the tablet printing apparatus 1 is installed.

[0031] A first diffusion prevention plate 83 and a second diffusion prevention plate 84 are provided within the box 81. As shown in FIGS. 4 and 5 , the first diffusion prevention plate 83 is provided to partition the interior of the box 81 in the conveying direction A2, dividing the interior into two areas: an area where a drying device 26 (described later) is provided, and an area where a high-pressure gas injection nozzle 82 is provided. The second diffusion prevention plate 84 is a plate-shaped member extending in the width direction and is provided at an incline above the high-pressure gas injection nozzles 82A and 82B. One end of the second diffusion prevention plate 84 is provided at the right end of the bottom surface B1 as shown in FIG. 4 , and the other end is provided in proximity to the outer circumferential surface of the drive pulley 21b. The second diffusion prevention plate 84 is inclined so that the end near the outer circumferential surface of the drive pulley 21b is at a higher position. 5, the first diffusion prevention plate 83 and the second diffusion prevention plate 84 have notches at positions corresponding to the positions where the tablets T pass, and the inclination angle of the second diffusion prevention plate 84 is set to an angle that allows the tablets T to be transported through the notches without contacting them, depending on the thickness of the tablets T to be printed. In other words, the distances of the first diffusion prevention plate 83 and the second diffusion prevention plate 84 from the surface of the conveyor belt 21a at locations other than where the notches are provided are set to be smaller than the thickness of the tablets T.

[0032] As shown in FIG. 5, the gas suction port 85 is provided in an area between the high-pressure injection nozzles 82A and 82B in the width direction of the bottom surface B1. As shown in FIG. 4, the gas suction port 85 is connected to a suction device (not shown) such as a pump via a valve 851. The suction device may be the same as the suction device that reduces the pressure inside the suction chamber 21f. The driving of these devices is controlled by the control device 50. When the control device 50 controls the gas suction port 85 to apply a suction force, the space surrounded by the first diffusion prevention plate 83, the second diffusion prevention plate 84, the conveyor belt 21a on the outer periphery of the drive pulley 21b, and the bottom surface B1 is suctioned.

[0033] As shown in FIG. 1, a drying device 26 is provided within the box 81. This drying device 26 is a drying device common to the two rows of conveying paths and dries the ink applied to each tablet T on the conveying belt 21a. As the drying device 26, various drying units can be used, such as a blower that dries the object to be dried with air, or a blower that dries the object to be dried with warm or hot air using a heater that dries the object to be dried with radiant heat and air in combination. The drying device 26 is electrically connected to the control device 50, and its operation is controlled by the control device 50.

[0034] As shown in FIG. 5, the drying device 26 includes multiple gas nozzles 262A and 262B and a gas supply source (not shown) connected to the gas nozzles 262A and 262B via valves (not shown). Similar to the high-pressure gas injection nozzles 82A and 82B of the cleaning device 80, two gas nozzles 262A and 262B of the drying device 26 are provided corresponding to the two rows of conveyance paths, and gas is blown out from each of the gas nozzles 262A and 262B toward the lower conveyance surface of the conveyor belt 21a. The gas nozzles 262A and 262B are pipes having multiple outlets 26g, which are aligned in a row along the longitudinal direction of the pipes. The gas nozzles 262A and 262B are arranged such that their longitudinal directions are aligned with the conveyance direction A2 and penetrate the first diffusion prevention plate 83. The plurality of blowout ports 26g are provided on the left side of the first diffusion prevention plate 83 in FIG. 4, and are not provided beyond the first diffusion prevention plate 83 to the right side. The gas supplied from the gas nozzles 262A, 262B is air, nitrogen, dry nitrogen, or the like. The strength of the gas blown from the gas nozzles 262A, 262B onto the conveyor belt 21a (amount of gas supplied per unit time) is set to be weaker than the strength of the gas blown by the previously described high-pressure injection nozzles 82A, 82B. The drying device 26 blows gas when the tablets T are held on the conveyor belt 21a, and this is to prevent the tablets T from being blown away by the gas and falling from the conveyor belt 21a.

[0035] The tablets T that have passed above the drying device 26 are transported along with the movement of the conveyor belt 21a, and reach a position near the end of each driven pulley 21c side of the conveyor device 21. At this position, the suction action no longer acts on the tablets T, and the tablets T are released from the state held by the conveyor belt 21a and are transferred from the first printing device 20 to the second printing device 30.

[0036] The second printing apparatus 30 includes a conveying device 31, a detecting device 32, a first imaging device 33, a print head device 34, a second imaging device 35, and a drying device 36. The conveying device 31 includes a conveying belt 31a, a driving pulley (pulley body) 31b, multiple (three in the example of FIG. 1) driven pulleys (pulley bodies) 31c, a motor (driving unit) 31d, a position detector 31e, and a suction chamber (suction unit) 31f. The detecting device 32, the first imaging device 33, the print head device 34, and the second imaging device 35 are housed in a cover 60. In this specification, the "upper conveying surface" of the conveying belt 31a refers to the plane between the symbols g and h in FIG. 1, the "left conveying surface" of the conveying belt 31a refers to the curved surface between the symbols h and i in FIG. 1, and the "lower conveying surface" of the conveying belt 31a refers to the plane between the symbols i and j in FIG. 1. The second printing device 30 does not have the cleaning device 80 that the first printing device 20 has, and is provided with only a rectifying plate (not shown) similar to the bottom surface B1 of the cleaning device 80. The other elements that make up the second printing device 30 have basically the same structure as the corresponding components of the first printing device 20 described above, and therefore their description will be omitted.

[0037] The recovery device 40 includes a defective product recovery device 41 and a non-defective product recovery device 42. This recovery device 40 is located downstream in the conveying direction A1 from the position where the drying device 36 of the second printing device 30 is provided, and the defective product recovery device 41 recovers defective tablets T, and the non-defective product recovery device 42 recovers non-defective tablets T.

[0038] The defective product recovery device 41 has a spray nozzle 41a and a storage unit 41b. The spray nozzle 41a is provided in the suction chamber of the second printing device 30, and sprays gas (e.g., air) toward tablets T (defective tablets T) conveyed by the conveyor belt 31a, causing the tablets T to fall from the conveyor belt 31a. At this time, the gas sprayed from the spray nozzle 41a passes through suction holes in the conveyor belt 31a and hits the tablets T. The suction holes are the same as the suction holes 21g shown in FIG. 2. The spray nozzle 41a is electrically connected to the control device 50, and its drive is controlled by the control device 50. The storage unit 41b receives and stores the tablets T that have fallen from the conveyor belt 31a.

[0039] The non-defective product collecting device 42 has a gas blowing section 42a, a discharge conveying device (discharge feeder) 42b, a drying device 42c, a storage section 42d, and a cover 42e. The non-defective product collecting device 42 is located downstream in the conveying direction A1 from the position where the defective product collecting device 41 is located.

[0040] The gas blowing unit 42a is provided in the conveying device 31 of the second printing device 30, at an end of the conveying device 31, i.e., at the end of the conveying belt 31a on the side of each driven pulley 31c. The gas blowing unit 42a constantly blows gas (e.g., air) toward the conveying belt 31a during, for example, the printing process, causing the tablets T to fall from the conveying belt 31a. At this time, the gas blown out from the gas blowing unit 42a passes through suction holes in the conveying belt 31a and hits the tablets T. The suction holes are the same as the suction holes 21g shown in FIG. 2. For example, an air blower having a slit-shaped opening extending in a direction intersecting (e.g., perpendicular to) the conveying direction A1 in a horizontal plane can be used as the gas blowing unit 42a. The gas blowing unit 42a is electrically connected to the control device 50, and its drive is controlled by the control device 50.

[0041] Here, the tablets T that have passed through the defective product collecting device 41 are transported along with the movement of the conveyor belt 31a, and reach a position near the end of the conveyor belt 31a on the side of each driven pulley 31c. At this position, the suction action no longer acts on the tablets T, but by providing the gas blowing section 42a, the tablets T can be reliably dropped from the conveyor belt 31a and supplied to the discharge conveying device 42b.

[0042] The discharge and conveying device 42b receives the tablets T that have dropped from the lower conveying surface of the conveyor belt 31a, and conveys the received tablets T to the storage section 42d. As the discharge and conveying device 42b, for example, a belt conveying mechanism can be used. The discharge and conveying device 42b is electrically connected to the control device 50, and its driving is controlled by the control device 50.

[0043] The drying device 42c is provided above the discharge and conveying device 42b. This drying device 42c dries the ink applied to each tablet T in addition to the drying devices 26 and 36. As the drying device 42c, various drying units can be used, such as a blower that dries the object to be dried with air, a heater that dries the object to be dried with radiant heat, or a blower that dries the object to be dried with warm or hot air using both air and a heater. The drying device 42c is electrically connected to the control device 50, and its operation is controlled by the control device 50.

[0044] Here, an example of a drying device 42c that uses air for drying will be described. The housing of this air-type drying device 42c is formed with a U-shaped cross section, with the bottom open so that it can cover the discharge and conveying device 42b. Air nozzles that blow air are arranged inside the housing of the drying device 42c, and the air is blown from the air nozzles toward the conveying surface, which is the upper surface of the discharge and conveying device 42b. This air flows along the conveying surface of the discharge and conveying device 42b toward the upstream end or downstream end of the discharge and conveying device 42b. Note that the air nozzles may have any shape. For example, it is possible to provide multiple openings in the longitudinal direction of a pipe and arrange one or more pipes that blow air from these openings. The openings are arranged in line along the longitudinal direction of the pipe. The pipes may be arranged so that their longitudinal directions are aligned with the conveying direction A1 or so that they intersect.

[0045] The storage unit 42d is positioned at the downstream end of the discharge and conveyance device 42b, i.e., at the end of the discharge and conveyance device 42b opposite the conveyance device 31, and is provided, for example, outside the housing of the tablet printing device 1. This storage unit 42d receives and stores the tablets T, whose ink has been dried by the drying device 42c, from the discharge and conveyance device 42b.

[0046] The cover 42e covers the discharge conveying device 42b, the drying device 42c, etc. This cover 42e is provided above the discharge conveying device 42b and the drying device 42c. The cover 42e prevents powder of the tablets T flying from above the cover 42e from adhering to the discharge conveying device 42b, the drying device 42c, etc., and also prevents tablets T that have fallen from the lower conveying surface of the conveyor belt 21a from being mixed in with non-defective tablets.

[0047] The control device 50 comprises an image processing unit 51, a print processing unit 52, an inspection processing unit 53, and a memory unit 54. The image processing unit 51 processes images. The print processing unit 52 performs processing related to printing. The inspection processing unit 53 performs processing related to inspection. The memory unit 54 stores various information such as processing information and various programs. Such a control device 50 controls the supply device 10, the first printing device 20, and the second printing device 30, and also receives position information of the tablets T transmitted from the individual detection devices 22, 32 of the first printing device 20 and the second printing device 30, and images transmitted from the individual imaging devices 23, 25, 33, 35 of the first printing device 20 and the second printing device 30.

[0048] (Printing process) Next, a description will be given of the printing process performed by the above-mentioned tablet printing apparatus 1. The printing process includes an inspection process. For example, the control device 50 executes the printing process including the inspection process.

[0049] First, various information such as print data required for printing is stored in the memory unit 54 of the control device 50. Then, when a large number of tablets T to be printed are placed in the hopper 11 of the supply device 10, the tablets T begin to be sequentially supplied from the hopper 11 to the aligning / conveying device 12, and are arranged in two rows and moved by the aligning / conveying device 12. The tablets T moving in these two rows are sequentially supplied to the conveyor belt 21a of the first printing device 20 by the relay conveying device 13. At this time, the position of the tablets T in the relay conveying device 13 is taken over by the conveyor belt 21a. The conveyor belt 21a is rotated by the rotation of the drive pulley 21b and each driven pulley 21c driven by the motor 21d. Therefore, the tablets T supplied onto the conveyor belt 21a are lined up in two rows on the conveyor belt 21a and conveyed in the conveying direction A1 at a predetermined moving speed. The conveyor belt 31a is also rotated by the rotation of the drive pulley 31b and each driven pulley 31c driven by the motor 31d.

[0050] Thereafter, the tablet T on the conveyor belt 21a is detected by the detection device 22. As a result, position information of the tablet T (position in the conveying direction A1) is acquired and input to the control device 50. This position information of the tablet T is stored in the memory unit 54 and used in post-processing. Next, the tablet T on the conveyor belt 21a is imaged by the first imaging device 23 at a timing based on the position information of the tablet T described above, and the captured image is transmitted to the control device 50. Based on each image transmitted from the first imaging device 23, positional deviation information of the tablet T (for example, the positional deviation of the tablet T in the X direction, Y direction, and θ direction in FIG. 2) is generated by the image processing unit 51 and stored in the memory unit 54. Based on this positional deviation information of the tablet T, printing conditions for the tablet T (for example, the ink ejection position and ejection speed) are set by the print processing unit 52 and stored in the memory unit 54.

[0051] Here, the positions of the tablet T in the X and Y directions are, for example, positions in an XY coordinate system relative to the center (reference position) of the imaging area of ​​the imaging unit 23a. The position in the θ direction is, for example, a position indicating the degree of rotation of the tablet T relative to the center line in the Y direction of the imaging area of ​​the imaging unit 23a. This position in the θ direction is detected when the tablet T has a shape with directionality, such as when a score line is provided on the tablet T or when the tablet T is molded into an oval, elliptical, rectangular, or other shape.

[0052] Next, printing is performed on each tablet T on the conveyor belt 21a by the print head device 24 based on the printing conditions described above at a timing based on the position information of the tablet T described above, that is, at the timing when the tablet T reaches below the print head device 24. In each inkjet head 24a of the print head device 24, ink is appropriately ejected from each nozzle 24b, and identification information such as letters (e.g., alphabets, katakana, numbers) and marks (e.g., symbols, figures) is printed on the top surface of the tablet T.

[0053] The tablet T on which the identification information is printed is imaged by the second imaging device 25 at a timing based on the position information of the tablet T described above, and the imaged image is transmitted to the control device 50. Based on the individual images transmitted from the second imaging device 25, printing position information indicating the printing position of the printing pattern for each tablet T is generated by the image processing unit 51 and stored in the memory unit 54. Based on the printing position information, the inspection processing unit 53 determines whether the printing on the tablet T is good or bad, and printing result information indicating the result of the printing quality for each tablet T is stored in the memory unit 54. For example, it is determined whether the printing pattern is printed at a predetermined position on the tablet T.

[0054] After inspection, the tablet T is transported along with the movement of the conveyor belt 21a and passes above the cleaning device 80 and drying device 26. At this time, the cleaning device 80 is not operating. That is, the valve 82 of the high-pressure injection nozzles 82A and 82B and the valve 851 of the gas suction port 85 are closed. The ink applied to the tablet T is dried by the drying device 26 while the tablet T passes above the drying device 26, and the tablet T with dried ink is transported along with the movement of the conveyor belt 21a and positioned near the end of the conveyor belt 21a on the side of each driven pulley 21c. At this position, the suction effect no longer acts on the tablet T, and the tablet T is released from its hold on the lower conveying surface of the conveyor belt 21a and is passed from the first printing device 20 to the second printing device 30.

[0055] In the second printing device 30, the printing process and inspection process are performed in the same manner as described above. After inspection, the tablets T are transported along with the movement of the conveyor belt 31a and pass above the drying device 36. Then, the tablets T with dried ink reach the defective product recovery device 41. At this position, the defective tablets T fall from the lower conveying surface of the conveyor belt 31a due to the gas injection from the injection nozzle 41a and are collected by the storage section 41b. On the other hand, the non-defective tablets T pass through the defective product recovery device 41 and reach the non-defective product recovery device 42. At this position, the suction action on the non-defective tablets T ceases to act on the tablets T, and the gas is blown out by the gas blowing section 42a, causing them to fall from the lower conveying surface of the conveyor belt 31a and be delivered to the discharge conveying device 42b. Then, the non-defective tablets T are transported by the discharge conveying device 42b, and during the transport, the ink on the tablets T is completely dried by the drying device 42c. The tablets T with dried ink are transported by the discharge transport device 42b to above the storage section 42d, drop from the downstream end of the discharge transport device 42b, and are collected by the storage section 42d.

[0056] The drying device 42c can reliably dry the tablets T by again drying the tablets T that have already been dried by the drying device 26 of the first printing device 20 and the drying device 36 of the second printing device 30. Furthermore, by blowing gas using the drying device 42c, it is possible to prevent powder with the ink used in printing from adhering to areas of the tablets T other than the printed portion, and it is possible to prevent the tablets T from becoming contaminated tablets after printing.

[0057] (Conveyor belt cleaning process) Next, the cleaning process performed by the tablet printing apparatus 1 will be described with reference to Fig. 6. For example, the control device 50 executes the cleaning process.

[0058] During printing, tablets T are supplied to the first printing device 20 and are present in the first printing device 20 and the second printing device 30, but for example, during maintenance of the conveying device 21 (conveyor belt cleaning process), tablets T are not supplied to the first printing device 20 and are not present in the first printing device 20 and the second printing device 30. For example, during maintenance, the control device 50 may stop the tablet supply operation of the supplying device 10, or the user may not insert tablets into the supplying device 10.

[0059] As shown in FIG. 6, in step S11, the control device 50 determines whether maintenance has started (for example, whether the print mode has been switched to the maintenance mode). The print mode may be switched to the maintenance mode periodically, for example, or may be switched by a user's input operation to an input unit (not shown) electrically connected to the control device 50. When the control device 50 determines that maintenance has started (Yes in step S11), in step S12, the control device 50 opens the valves 821a and 821b of the high-pressure injection nozzles 82A and 82B of the cleaning device 80 and the valve 851 of the gas suction port 85, thereby supplying gas from the gas supply source 822 to the high-pressure injection nozzle 82 and sucking the gas through the gas suction port 85. As a result, gas is injected from the high-pressure injection nozzle 82 toward the conveyor belt 21a, and the gas is sucked through the gas suction port 85. Furthermore, during printing, the conveying speed of the conveyor belt 21a is reduced and the flow rate of the tablet suction gas is increased (i.e., the suction force applied to the suction holes 21g by the suction chamber 21f is strengthened). Note that increasing the flow rate means increasing the flow rate.

[0060] Specifically, the control device 50 opens the valves 821a and 821b, sprays a predetermined amount of gas onto the conveyor belt 21a, and controls the motor 21d of the conveyor device 21 to slow the conveying speed of the conveyor device 21 from the predetermined speed. The control device 50 increases the valve opening in the area corresponding to the right conveying surface of the suction chamber 21f of the conveyor device 21 to increase the flow rate of the tablet adsorbing gas from the predetermined amount. Each predetermined amount and predetermined speed are preset. The control device 50 also opens the valve 851 of the gas suction port 85 to aspirate a predetermined amount of gas. Here, the predetermined amount of gas is set so that the flow rate of the tablet adsorbing gas and the predetermined amount of gas aspirated through the gas suction port 85 are approximately balanced with the amount of gas supplied from the high-pressure injection nozzles 82A and 82B. By setting the gas supply amount and suction amount in this manner, it is possible to prevent foreign matter removed from the conveyor belt 21a from diffusing outside the box 81.

[0061] In step S13, the control device 50 determines whether or not maintenance has been completed (for example, whether or not the maintenance mode has been switched to the print mode). If the control device 50 determines that maintenance has been completed (Yes in step S13), in step S14, the control device 50 stops the supply of gas from the high-pressure gas injection nozzle 82 and the suction from the gas suction port 85, and restores the conveying speed and the flow rate of the tablet adsorbing gas to their original values.

[0062] Specifically, the control device 50 closes the valves 821a and 821b, controls the motor 21d of the conveying device 21 to increase the conveying speed of the conveying device 21 and return it to the original predetermined speed, reduces the opening amount of the valve of the suction chamber 21f of the conveying device 21 to return the flow rate of the tablet adsorbing gas to the original predetermined amount, and closes the valve 851 of the gas suction port 85.

[0063] According to this cleaning process for the conveyor belt 21a, during maintenance, high-pressure gas is sprayed from the high-pressure gas injection nozzles 82 (82A, 82B) onto the outer surface of the conveyor belt 21a, and the gas is sucked through the gas suction port 85. Therefore, foreign matter such as powder of tablets T adhering to the conveyor belt 21a is removed by the gas sprayed from the high-pressure gas injection nozzles 82A, 82B and sucked through the gas suction port 85. This makes it possible to remove powder of tablets T and foreign matter from the conveying surface of the conveyor belt 21a. Therefore, it is possible to suppress the occurrence of false detection and poor conveyance of tablets T, and to efficiently print on tablets T.

[0064] Furthermore, during maintenance, the conveying speed is reduced compared to during printing, and the flow rate of the tablet adsorbing gas is increased compared to during printing. In other words, the conveying speed is set to be lower (slower) during maintenance than during printing, and the flow rate of the tablet adsorbing gas is set to be higher during maintenance than during printing. As a result, the conveying speed is reduced during maintenance, making it possible to slowly clean the conveying surface of the conveying belt 21a, and the conveying surface of the conveying belt 21a can be reliably cleaned. Furthermore, since the flow rate of the tablet adsorbing gas is increased during maintenance, some of the tablet T powder and gas removed by spraying from the high-pressure gas injection nozzles 82 (82A, 82B) can be sucked through each suction hole 21g of the conveying belt 21a. This allows the conveying surface of the conveying belt 21a to be reliably cleaned.

[0065] The high-pressure gas injection nozzles 82 (82A, 82B) are inclined at positions where gas is sprayed toward the surface of the conveyor belt 21a, which is located below the position where the rotation axis 21b1 (center axis) of the drive pulley 21b is located. As shown in FIG. 4, the high-pressure gas injection nozzles 82 (82A, 82B) are inclined at an angle α that is shallower than the angle between the bottom surface B1 and a line (normal) V that passes through the base of the high-pressure gas injection nozzle 82 and is perpendicular to the tangent line S of the outer shape of the drive pulley 21b. The angle α is set to be larger than the angle parallel to the bottom surface B1. The base of the high-pressure gas injection nozzle 82 may be set at a position that passes through the center of each of the high-pressure gas injection nozzles 82A and 82B in the direction perpendicular to the conveying direction A2.

[0066] Because the gas is sprayed at such an angle, the gas is sprayed in the direction of rotation of the drive pulley 21b with respect to the tangent line S, i.e., downward, on the surface of the conveyor belt 21a that the gas hits, and the powder of the tablets T removed by the sprayed gas is less likely to scatter toward the upper conveying surface. For example, if the spray angle of the high-pressure gas spray nozzle 82 is in the direction toward the central axis 21b1 of the drive pulley 21b and is at an angle perpendicular to the tangent line S (i.e., when the gas is sprayed at the angle indicated by the straight line V), after the gas collides with the outer surface of the conveyor belt 21a, it will scatter radially, and a lot of powder will scatter toward the upper conveying surface. In contrast, when the injection angle of the high-pressure gas injection nozzle 82 is angle α, which is shallower than the angle between the straight line V and the bottom surface B1, some of the gas that collides with the outer surface of the conveyor belt 21a flows upward, but most of it is directed downward, preventing the gas from the high-pressure gas injection nozzle 82 and the powder of the tablets T removed by the gas from flowing onto the upper conveying surface. By injecting the high-pressure gas at such an angle, most of the powder removed from the lower conveying surface of the conveyor belt 21a flows downward. In this way, the powder of the tablets T removed from the surface of the conveyor belt 21a by the gas from the high-pressure gas injection nozzle 82 is more likely to be guided to the suction holes 21g and the gas suction port 85, and is reliably sucked and collected from the suction holes 21g and the gas suction port 85. In addition, a non-defective product recovery device 42 is provided below the cleaning device 80, and the non-defective product recovery device 42 is provided with a cover 42e to prevent the inclusion of fallen tablets, etc., so that even if powder falls, it will not affect the tablets T being transported by the discharge and conveying device 42b of the non-defective product recovery device 42.

[0067] As described above, according to the first embodiment, the tablet printing apparatus 1 comprises a conveying device 21 that conveys tablets T, an inkjet head 24a that prints on tablets T conveyed by the conveying device 21, and high-pressure gas injection nozzles 82 (82A, 82B) that spray gas toward the conveying device 21. The high-pressure gas injection nozzles 82 (82A, 82B) inject high-pressure gas onto the conveying surface of the right-hand conveying surface. In addition, the gas suction port 85 can suck and remove powder of tablets T removed by the high-pressure gas injection nozzle 82. Therefore, it is possible to suppress the occurrence of erroneous detection and conveying failures as described above, and therefore it is possible to efficiently print on tablets T.

[0068] In this embodiment, the cleaning device 80 is provided only in the conveying device 21. This is because the surface of the tablet T that contacts the conveying surface of the conveyor belt 31a in the conveying device 31 is the same as the surface that contacts the conveying surface of the conveyor belt 13a of the relay conveying device 13. As described above, this is the surface from which powder adhering to the surface that contacts the conveyor belt 13a has been removed, and this is because even if the cleaning device 80 is not provided in the conveying device 31, false detection or conveying failure due to powder adhering to the conveyor belt 31a does not occur. In cases where false detection or conveying failure occurs due to powder of the tablet T adhering to the conveyor belt 31a of the conveying device 31 even after suction in the conveyor belt 13a, or when conveying and processing types of tablets that generate a particularly large amount of powder, the cleaning device 80 may also be provided in the conveying device 31, and a process similar to the conveyor belt cleaning process by the cleaning device 80 in the conveying device 21 may be performed simultaneously.

[0069] Furthermore, the gas suction port 85 does not necessarily need to be provided. For example, it may not be provided if the powder can be removed by suction from the suction holes 21g of the conveyor belt 21a. In this case, the suction holes 21g (and the suction pipe of the suction chamber 21f, the suction device, and the control device 50) function as the gas suction unit. Suction from the gas suction port 85 may be continued without stopping even during printing, as long as the force is not such that the tablet T falls from the conveyor belt 21a. By continuing suction from the gas suction port 85 even during printing, powder from the tablet T generated during printing can be sucked and removed as needed. A plate-like mesh may be provided in the gas suction port 85 to prevent the tablet T from falling into the suction pipe and clogging it. When suction from the gas suction port 85 is continued even during printing, it is preferable to provide the gas suction port 85 at a position relatively far from the conveyor belt 21a (a position near the corner of the box 81 as shown in FIG. 4) in order to minimize the impact on the tablet T adsorbed and held on the conveyor belt 21a.

[0070] Furthermore, in this embodiment, the flow rate of the tablet adsorbing gas during maintenance is increased compared to that during printing, but the flow rate may be the same as that during printing. The high-pressure gas injection nozzle 82 is provided at a position corresponding to the right-side conveying surface, and a stronger suction force is applied to the suction holes 21g of the right-side conveying surface than to other areas. By injecting gas from the high-pressure gas injection nozzle 82 into this area, depending on the type of tablet T, powder can be sucked and removed even at a flow rate equivalent to that during printing.

[0071] Furthermore, in this embodiment, only the cleaning process of the conveyor belt has been exemplified as maintenance, but this is not limiting, and maintenance of the print head devices 24, 34 may be performed at the same time. Known inkjet head maintenance methods can be adopted for maintenance of the print head devices 24, 34. When performing maintenance on the print head devices 24, 34, the nozzle surface of the inkjet head 24a is covered with a drain pan or capped. Therefore, by simultaneously performing the cleaning process of the conveyor belt, even if an airflow that promotes drying of the nozzles of the inkjet head 24a is generated by, for example, increasing the flow rate of the tablet adsorbing gas applied to the suction holes 21g compared to during printing, it is less likely to have an effect such as drying the ejection surface of the inkjet head 24a.

[0072] In addition, in this embodiment, two high-pressure injection nozzles 82, high-pressure injection nozzle 82A and high-pressure injection nozzle 82B, are provided to correspond to the two rows of conveying paths, but this is not limited to this, and one nozzle common to the two rows of conveying paths may be provided.

[0073] <Other embodiments> In the above description, printing is performed on tablets T using the tablet printing apparatus 1 (tablet printing method) according to one embodiment, but this can also be rephrased as printing on tablets T using the tablet printing apparatus 1 (tablet printing method) according to one embodiment and manufacturing printed tablets T. In other words, the tablet printing apparatus 1 can be rephrased as a tablet manufacturing apparatus, and the tablet printing method can be rephrased as a tablet manufacturing method.

[0074] In addition, in the above explanation, an example was given in which the tablets T were transported in two rows, but this is not limited to this, and the number of rows may be one, three, four or more, and is not particularly limited. The number of each conveyor belt 13a, 21a, 31a may also be two or more, and is not particularly limited. Furthermore, the number of inkjet heads 24a may also be two or more, and is not particularly limited.

[0075] In the above description, a print head in which the nozzles 24b are arranged in a single row has been exemplified as the inkjet head 24a, but this is not limiting and, for example, a print head in which the nozzles 24b are arranged in multiple rows may also be used. Furthermore, a plurality of inkjet heads 24a may be arranged in a direction perpendicular to the transport direction A1 (or transport direction A2) in a horizontal plane.

[0076] In addition, in the above description, an example was given of the inkjet head 24a being arranged so that the direction in which the nozzles 24b are arranged is perpendicular to the conveying direction A1 (or conveying direction A2) in a horizontal plane, but this is not limited to this, and for example, the nozzles 24b may be arranged so that the direction in which they are arranged is a direction that intersects with the conveying direction A1 (or conveying direction A2) in a horizontal plane.

[0077] In the above description, the first printing device 20 and the second printing device 30 are arranged one above the other to print on both sides or one side of the tablets T, but this is not limited to this. For example, only the first printing device 20 may be provided to print on only one side of the tablets T. For example, the tablets T may be supplied onto the conveyor belt 21a at regular intervals or randomly.

[0078] In the above description, the conveyor belts 21a, 31a are exemplified as having suction holes 21g, but the present invention is not limited to this, and the conveyor belts 21a, 31a themselves may be made of a mesh material instead of the suction holes 21g. In other words, the conveyor belts 21a, 31a may have a portion that allows gas to pass through (gas permeable) so that the tablets T can be sucked and held by the conveyor belts 21a, 31a.

[0079] Here, the aforementioned tablets T can include tablets used for medicine, food and beverage, cleaning, industrial use, or fragrance. Tablets T include plain tablets (plain tablets), sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-coated tablets, multilayer tablets, and dry-coated tablets, and various capsule tablets such as hard capsules and soft capsules can also be included in tablets T. Tablets T can have various shapes, such as a disk, lens, triangle, or oval. When the tablet T to be printed is for medicine or food and beverage use, edible ink is preferably used. As the edible ink, any of synthetic pigment ink, natural pigment ink, dye ink, and pigment ink may be used.

[0080] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0081] 1. Tablet printing equipment 10 Feeding device 11 Hopper 12 Alignment and conveyance device 13. Relay transport equipment 13a Conveyor belt 13b Drive pulley 13c Driven pulley 13d Motor 13e Suction chamber 14 Rectifier plate 20 First printing device 21 Conveyor equipment 21a Conveyor belt 21b Drive pulley 21c Driven pulley 21d Motor 21e Position detector 21f Suction Chamber 21g suction hole 22 Detection device 22a Detector 23 First imaging device 23a Imaging unit 24 Print head unit 24a inkjet head 24b nozzle 25 Second imaging device 25a Imaging unit 26 Drying equipment 30 Second printing device 31 Transport device 31a Conveyor belt 31b Drive pulley 31c Driven pulley 31d Motor 31e Position detector 31f Suction chamber 32 Detection device 33 First imaging device 34 Print head device 35 Second imaging device 36 Drying equipment 40 Recovery Device 41 Defective product recovery device 41a Injection nozzle 41b Storage section 42 Good product recovery device 42a Gas outlet 42b Discharge conveying device 42c drying equipment 42d Storage section 42e cover 50 Control device 51 Image processing section 52 Print processing unit 53 Inspection processing section 54 Memory section 60 Cover 80 Cleaning equipment Box 81 82 High-pressure gas injection nozzle 821 Valve 83 First diffusion prevention plate 84 Second diffusion prevention plate 85 Gas suction port 851 Valve 262A Gas Nozzle 262B Gas Nozzle A1 Conveying direction A2 Conveying direction M1 receiving surface B1 Bottom T tablets

Claims

1. a conveying device including a conveying belt and a pulley that can rotate the conveying belt, and that adsorbs and holds tablets on the conveying belt to convey the tablets; an inkjet head that prints on the tablets transported by the transport device; a cleaning device that cleans the conveyor belt, The cleaning device is a box that covers a part of the conveyor belt; a gas blowing device provided in the box and configured to blow gas toward the conveying device; a gas suction unit that suctions and removes foreign matter attached to the conveying device that has been removed by the gas blowing device; Equipped with The tablet printing apparatus is characterized in that the gas blowing device blows the gas onto the outer surface of the conveyor belt around the outer periphery of the pulley.

2. the gas blowing device is provided at an inclination angle capable of blowing the gas onto an outer surface of the conveyor belt located below the central axis of the pulley, The tablet printing device described in claim 1, characterized in that the inclination angle is an angle shallower than the angle between a line passing through the base of the gas spray device and perpendicular to the tangent to the outer shape of the pulley and the bottom surface of the box, and an angle larger than the angle parallel to the bottom surface of the box.

3. the conveying device has a suction chamber that applies a suction force to the conveying belt so that the tablet can be adsorbed and held, the suction chamber has a plurality of regions capable of applying different suction forces; A tablet printing device as described in claim 1 or 2, characterized in that the gas blowing device is arranged at a position where it can blow the gas onto the conveying belt at a position corresponding to the area to which the strongest suction force is applied among the plurality of areas.

4. a first diffusion prevention plate and a second diffusion prevention plate provided in the box and positioned closer to the outer peripheral surface of the pulley than to the bottom surface of the box; the first diffusion prevention plate is provided to partition the box in the conveying direction of the tablets, the second diffusion plate is provided inclined from the bottom surface of the box toward the outer periphery of the pulley, The gas suction portion is provided on the bottom surface of the box, 3. The tablet printing device according to claim 1, wherein the gas suction unit suctions the space surrounded by the first diffusion plate, the second diffusion prevention plate, the conveying belt on the outer periphery of the pulley, and the bottom surface.

5. 3. The tablet printing apparatus according to claim 1, wherein the gas blowing device blows the gas toward the conveying device when the conveying device is not conveying the tablets.

6. A conveying device including a conveying belt and a pulley that can rotate the conveying belt conveys the tablets; an inkjet head prints on the tablets transported by the transport device; a gas blowing device blowing gas onto the outer surface of the conveyor belt around the outer periphery of the pulley of the conveyor device; A tablet printing method in which a gas suction unit suctions and removes foreign matter adhering to the conveying device that has been removed by the gas blown by the gas blowing device.

Images