JP7752010B2 - Tablet printing device and tablet printing method - Google Patents

Description

Embodiments of the present invention relate to a tablet printing device and a tablet printing method.

A printing technique using an inkjet head is known for printing identification information (an example of information) such as letters or marks on tablets. A tablet printing device using this technique transports tablets using a transport device such as a conveyor, and ejects ink from each nozzle of an inkjet head located above the transport device onto the tablets as they pass below the inkjet head, printing the identification information on the tablets.

However, such tablet printing devices may also perform visual inspections, such as checking for chips or cracks in the tablets, and printing inspections after the identification information has been printed on the tablets, all within the same device. When performing these various inspections, depending on the location of the sensors, cameras, etc. used for the inspection, printing and inspection may not be performed properly.

Japanese Patent Application Laid-Open No. 2015-204943

The problem that embodiments of the present invention aim to solve is to provide a tablet printing device and tablet printing method that can perform tablet inspection effectively.

A tablet printing device according to an embodiment of the present invention is enclosed in a housing having a rectangular appearance , and prints identification information on tablets by ejecting ink from a print head device onto the tablets , the tablet printing device having a supply device that supplies the tablets, a first printing device that transports the tablets supplied from the supply device by a first conveyor belt and performs a printing process on one side of the tablets, and a second printing device that transports the tablets received from the first printing device by a second conveyor belt and performs a printing process on the other side of the tablets, the housing having a first side wall and a second side wall that face each other in the direction in which the tablets are transported by the first conveyor belt, the supply device and the second printing device are arranged side by side vertically on the first side wall side, the first printing device is arranged on the second side wall side at a higher position than the second printing device, the first printing device is a first print head device that prints on the one side of the tablets, and is arranged between the first print head device and the second side wall, and a first three- dimensional image acquisition unit that acquires a three-dimensional image of the tablet printed by a print head device , the second printing device having a second print head device that prints on the other side of the tablet and a second three-dimensional image acquisition unit that is provided between the second print head device and the first side wall and acquires a three-dimensional image of the tablet printed by the second print head device, the first three-dimensional image acquisition unit and the second three-dimensional image acquisition unit each having a laser light irradiation unit and a three-dimensional image capturing camera, and a control device that controls the first print head device, the second print head device, the first three-dimensional image acquisition unit, and the second three-dimensional image acquisition unit, the control device processes the three-dimensional images acquired by the first three-dimensional image acquisition unit and the second three-dimensional image acquisition unit, and performs an appearance inspection of the tablet, and has a first cooling means that is provided on the second side wall and supplies gas to the first three-dimensional image acquisition unit, and a second cooling means that is provided on the first side wall and supplies gas to the second three-dimensional image acquisition unit .

1 is an overall schematic view of a tablet printing apparatus according to a first embodiment; 1 is a partially enlarged view of a tablet printing apparatus according to a first embodiment. FIG. FIG. 2 is a schematic diagram of a first side image acquisition unit of the tablet printing apparatus according to the first embodiment. FIG. 2 is a schematic diagram of a first three-dimensional image acquisition unit of the tablet printing apparatus according to the first embodiment. FIG. 2 is a schematic diagram of a second side image acquisition unit of the tablet printing apparatus according to the first embodiment. FIG. 10 is a schematic view of the entire tablet printing apparatus according to the second embodiment.

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

(Basic configuration)
As shown in Figure 1, a tablet printing device 1 according to one embodiment includes a supply device 10, a first printing device 20, a second printing device 30, a recovery device 40, and a control device (control unit) 50 within a housing B.

The first printing device 20 and the second printing device 30 have basically the same structure, except that some devices are installed in a different order. The components of the tablet printing device 1, namely the supply device 10, first printing device 20, second printing device 30, and collection device 40, are arranged in this order, and tablets T are transported in this order while a series of processes of supply, printing, and collection are carried out. The path along which the tablets T are transported is called the transport path P. In other words, the upstream side of the transport path P is the supply device 10 side, and the downstream side is the collection device 40 side. In this embodiment, two parallel transport paths P are formed.

The supply device 10 has a hopper 11, an alignment feeder 12, and a delivery feeder 13. The 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 of the first printing device 20. The hopper 11 stores a large number of tablets T and sequentially supplies the tablets T to the alignment feeder 12. The alignment feeder 12 aligns the supplied tablets T in two rows and transports them toward the delivery feeder 13. The delivery feeder 13 sequentially sucks in and holds each tablet T arranged in two rows on the alignment feeder 12 from the top side of the tablet T, transports the held tablets T in two rows to the first printing device 20, and delivers them to the first printing device 20. The supply device 10 is electrically connected to the control device 50, and its drive is controlled by the control device 50. The alignment feeder 12 and the delivery feeder 13 can be, for example, a belt conveying mechanism. The conveying direction of the transfer feeder 13 is indicated by arrow A2 (counterclockwise) in Figure 1.

The first printing device 20 includes a first conveying device (conveying unit) 21, a detecting device 22, a first imaging device (imaging device for printing) 23, a first side image acquisition unit SD1, a print head device 24 (first print head device), a second imaging device (imaging device for inspection) 25, a first three-dimensional image acquisition unit 3D1, and a drying device 26.

The first conveying device 21 has a conveying belt 21a, a driving pulley 21b, multiple (three in the example of Figure 1) driven pulleys 21c, a motor 21d, a position detector 21e, and a suction chamber 21f. The conveying belt 21a is an endless belt that 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 drive 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. The control device 50 can obtain information such as the position, speed, and movement amount of the conveying belt 21a based on the detection signal. In this first conveying device 21, the drive pulley 21b is rotated by the motor 21d, which rotates the conveying belt 21a together with the driven pulleys 21c, and conveys tablets T on the conveying belt 21a in the conveying direction A1 (clockwise), which is the direction of the arrow A1 in Figure 1.

As shown in FIG. 2, multiple 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 tablets T onto the surface of the conveyor belt 21a. They are arranged in two parallel rows along the conveying direction A1 to form two conveying paths P. Each suction hole 21g is connected to the inside of the suction chamber 21f via a suction path formed in the suction chamber 21f, allowing suction force to be generated by the suction chamber 21f. An air suction device such as a pump is connected to the suction chamber 21f via an air suction pipe (neither is shown), and operation of the air suction device reduces the pressure inside the suction chamber 21f. The air suction pipe is connected approximately to the center of the side of the suction chamber 21f (a surface parallel to the conveying direction A1). The air suction device is electrically connected to the control device 50, and its operation is controlled by the control device 50.

The detection device 22 has multiple detection units 22a (two in the example shown in Figure 2). The detection units 22a are arranged one for each conveyance path P 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 (e.g., perpendicular to) the conveyance direction A1 in the horizontal plane, and are provided above the conveyor belt 21a. The detection units 22a detect the position of the tablets T on the conveyor belt 21a (the position of the tablets T in the conveyance direction A1) by emitting 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.

The first imaging device 23 has multiple imaging units 23a (two in the example shown in Figure 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 P in a direction intersecting (e.g., perpendicular to) the conveying direction A1 in the horizontal plane, and are provided above the conveying belt 21a. Based on the position information of the tablet T described above, the imaging units 23a capture images of the tablet T when it arrives directly below the imaging units 23a, obtain images including the top surface of the tablet T (images for printing), and transmit the obtained images to the control device 50. The imaging units 23a can be various cameras equipped with imaging elements such as CCDs (charge-coupled devices) or CMOSs (complementary metal-oxide semiconductors). Each imaging unit 23a is electrically connected to the control device 50, and its operation is controlled by the control device 50. Illumination for imaging may also be provided as needed.

As shown in Figures 3(A) and (B), the first side image acquisition unit SD1 has a side imaging camera SC1, multiple reflecting mirrors (first reflecting mirror M1, second reflecting mirror M2), and a ring illumination R. Figure 3(A) is a front view of the first side image acquisition unit SD1, and Figure 3(B) is a plan cross-sectional view taken along line A-A in Figure 3(A). As shown in Figure 3(B), the ring illumination R is disposed above the conveyor belt 21a and parallel to it. Multiple first reflecting mirrors M1 and second reflecting mirrors M2 are arranged in a circular pattern concentrically with the ring center of the ring illumination R. The first reflecting mirror M1 is composed of eight mirrors and is disposed above the ring illumination R, extending perpendicular to the ring illumination R. The second reflecting mirror M2 is composed of eight mirrors and is disposed above the first reflecting mirror M1, tilted from the perpendicular to the ring illumination R. The tablet T reflects the light from the ring illumination R, and the light reflected by the tablet T is incident on the first reflecting mirror M1, then passes through a lens (not shown) that receives the light guided by the second reflecting mirror M2 and is received by the side image capturing camera SC1 (the light path is shown by a two-dot chain line in FIG. 3(A)). The first side image acquiring unit SD1 is arranged downstream in the conveying direction A1 from the position where the first imaging device 23 is provided, one for each conveying path P in a direction that intersects (for example, a direction perpendicular to) the conveying direction A1 in the horizontal plane, and is provided above the conveyor belt 21a. Based on the position information of the tablet T described above, the first side image acquiring unit SD1 uses the side image capturing camera SC1 to capture an image including the side of the tablet T (side image), and transmits the captured side image to the control device 50. The light intensity of the ring illumination is greater than the light intensity of the illumination of the first imaging device 23 described above.

Returning to FIG. 2, the print head device 24 has multiple inkjet print heads 24a (two in the example of FIG. 2). The print heads 24a are arranged downstream in the transport direction A1 from the position where the first imaging device 23 is provided, and are arranged one for each transport path P in a direction intersecting (e.g., perpendicular to) the transport direction A1 in the horizontal plane, above the transport belt 21a. Each print head 24a has multiple nozzles 24b (eight in the example of FIG. 2, but in reality, approximately several hundred to several thousand nozzles), and ink is ejected individually from each nozzle 24b. This print head 24a is arranged so that the alignment direction of the nozzles 24b intersects (e.g., perpendicular to) the transport direction A1 in the horizontal plane. Various inkjet print heads having drive elements such as piezoelectric elements, heat generating elements, or magnetostrictive elements can be used as the print heads 24a. Each print head 24a is electrically connected to the control device 50, and its drive is controlled by the control device 50.

The second imaging device 25 has multiple imaging units 25a (two in the example shown in Figure 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 P in a direction intersecting (e.g., perpendicular to) the conveying direction A1 in the horizontal plane, and are provided above the conveying belt 21a. Based on the position information of the tablet T described above, the imaging units 25a capture images of the tablet T when it arrives directly below the imaging unit 25a, obtain images including the top surface of the tablet T (images for inspection), and transmit the obtained images to the control device 50. As with the imaging unit 23a described above, various cameras equipped with 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 operation is controlled by the control device 50. Illumination for imaging may also be provided as necessary.

As shown in Figures 4(A) and (B), the first three-dimensional image acquisition unit 3D1 includes a laser light irradiation unit L1 that irradiates a band-shaped laser beam, a three-dimensional image acquisition camera C1 that captures an image of the surface of the tablet T irradiated with the laser beam, and a control device 50 that controls the laser light irradiation unit and the three-dimensional image acquisition camera and processes the image captured by the three-dimensional image acquisition camera. Figure 4(A) is a view of the first three-dimensional image acquisition unit 3D1 from the upstream side of the conveying direction A1, and Figure 4(B) is a view of the first three-dimensional image acquisition unit 3D1 from a direction perpendicular to the conveying direction A1. As shown in Figure 4(A), the laser light irradiation unit L1 irradiates the conveying belt 21a from directly above so that the irradiation line of the band-shaped laser beam irradiated onto the conveying belt 21a is perpendicular to the conveying direction A1. As shown in Figure 4(B), the three-dimensional image acquisition camera C1 captures an image of the tablet T from diagonally above downstream of the laser light irradiation unit L1 in the conveying direction A1. The image captured by the three-dimensional image capturing camera C1 is sent to the control device 50, where it is processed by the image processing unit 51 to obtain a three-dimensional image. By analyzing this, the three-dimensional shape of the tablet T is detected (the so-called light section method).

Returning to Figure 1, the drying device 26 is positioned downstream in the conveying direction A1 from the position where the print head device 24 is provided, and is provided, for example, below the first conveying device 21. This drying device 26 is common to the two rows of conveying paths P, and dries the ink applied to each tablet T on the conveying belt 21a. The drying device 26 can be any of a variety of drying units, such as a blower that dries using gas such as air, a heater that dries using radiant heat, or a blower that dries using warm or hot air using both gas and a heater. The drying device 26 is electrically connected to the control device 50, and its operation is controlled by the control device 50.

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 the conveyor belt 21a on the driven pulley 21c side. At this position, the suction action on the tablets T ceases, and the tablets T are released from their position on the conveyor belt 21a and are transferred from the first printing device 20 to the second printing device 30.

The second printing device 30 includes a conveying device 31, a detecting device 32, a first imaging device (imaging device for printing) 33, a print head device 34 (second print head device), a second imaging device (imaging device for inspection) 35, a second 3D image acquisition unit 3D2, a second side image acquisition unit SD2, and a drying device 36. The conveying device 31 includes a conveying belt 31a, a driving pulley 31b, multiple (three in the example of Figure 1) driven pulleys 31c, a motor 31d, a position detector 31e, and a suction chamber 31f. Each element constituting the second printing device 30 has essentially the same structure as the corresponding component of the first printing device 20 described above. Of these, the positions and orientations of the second side image acquisition unit SD2 and the second 3D image acquisition unit 3D2 differ. Therefore, only this portion will be described, and other explanations will be omitted. The transport direction of the second printing device 30 is the transport direction A2 (counterclockwise), which is the direction of arrow A2 in Figure 1.

In the second printing device 30, a second three-dimensional image acquisition unit 3D2 is provided downstream of the second imaging device 35 in the conveying direction A2, and a second side image acquisition unit SD2 is provided at a position facing the drive pulley 31b further downstream. The second three-dimensional image acquisition unit 3D2 has the same structure as the first three-dimensional image acquisition unit 3D1 of the first printing device 20. Unlike the first side image acquisition unit SD1, the second side image acquisition unit SD2 further includes a third reflecting mirror M3 (see FIG. 5) .

The first side image acquisition unit SD1 of the first printing device 20 is provided opposite the horizontal portion of the conveyor belt 21a (i.e., the flat portion of the upper surface forming the chamber 21f) and inspects the side of the tablet T held by suction approximately horizontally, whereas the second side image acquisition unit SD2 of the second printing device 30 is provided opposite the curved portion of the conveyor belt 31a (i.e., the curved portion of the drive pulley 31b) and inspects the side of the tablet T held by suction on the curved portion. As shown in Figure 5, similar to the first side image acquisition unit SD1 of the first printing device 20, a ring light R (not shown) , a first reflecting mirror M1, and a second reflecting mirror M2 are arranged to face the printed surface of the conveyed tablet, and a reflecting mirror M3 and a camera SC1 are arranged so that the reflected light reflected by the first reflecting mirror M1 and the second reflecting mirror M2 is reflected 90 degrees by a third reflecting mirror M3 and enters the camera via a lens not shown.

Returning to FIG. 1, the recovery device 40 includes a defective product recovery device 41, a reusable product recovery device 42, and a non-defective product recovery device 43. This recovery device 40 is located downstream in the conveying direction A2 from the position where the drying device 36 of the second printing device 30 is located. The recovery device 40 basically recovers defective tablets T using the defective product recovery device 41, recovers reusable tablets T (described below) using the reusable product recovery device 42, and recovers non-defective tablets T using the non-defective product recovery device 43.

The defective product collection device 41 has multiple spray nozzles 41a and a collection box (collection box) 41b. One spray nozzle 41a is provided for each transport path P, and one collection box 41b is provided in common for all transport paths P.

The spray nozzles 41a are arranged one for each conveyance path P in a direction intersecting (e.g., perpendicular to) the conveyance direction A2 in the horizontal plane, and are provided in the suction chamber 31f of the second printing device 30. The spray nozzles 41a spray gas (e.g., air) toward the conveyance belt 31a, causing tablets T to fall from the conveyance belt 31a. At this time, the gas sprayed from the spray nozzle 41a passes through suction holes (similar to suction holes 21g shown in Figure 2) in the conveyance belt 31a and hits the tablets T. The spray nozzles 41a are electrically connected to the control device 50, and their operation is controlled by the control device 50.

The storage boxes 41b are located directly below each spray nozzle 41a and below the conveyor device 31. These storage boxes 41b receive and store tablets T that fall from the conveyor belt 31a due to the gas sprayed from the spray nozzles 41a.

The spray nozzle 41a may be installed somewhere other than inside the suction chamber 31f of the second printing device 30. For example, the spray nozzle 41a may be installed below the conveying device 31, and gas may be sprayed toward the side of the tablet T being conveyed by the conveying belt 31a. In this case, the spray nozzle 41a may be installed at an angle to the vertical direction. In this case, the storage box 41b should be installed taking into account the gas spray direction of the spray nozzle 41a.

The reusable product recovery device 42 has multiple spray nozzles 42a and a storage box (recovery box) 42b. The multiple spray nozzles 42a are provided for each transport path P, and the storage box 42b is provided in common for all transport paths P.

The spray nozzles 42a are arranged one for each conveyance path P in a direction that intersects (e.g., perpendicular to) the conveyance direction A2 in the horizontal plane, and are provided in the suction chamber 31f of the second printing device 30. The spray nozzles 42a spray gas (e.g., air) toward the conveyance belt 31a, causing tablets T to fall from the conveyance belt 31a. At this time, the gas sprayed from the spray nozzle 42a passes through suction holes (similar to suction holes 21g shown in Figure 2) in the conveyance belt 31a and hits the tablets T. The spray nozzles 42a are electrically connected to the control device 50, and their operation is controlled by the control device 50.

The storage boxes 42b are located directly below each spray nozzle 42a and below the conveyor device 31. These storage boxes 42b receive and store tablets T that fall from the conveyor belt 31a due to the gas sprayed from the spray nozzles 42a.

The spray nozzle 42a may be installed somewhere other than inside the suction chamber 31f of the second printing device 30. For example, the spray nozzle 42a may be installed below the conveying device 31, and gas may be sprayed toward the side of the tablet T being conveyed by the conveying belt 31a. In this case, the spray nozzle 42a may be installed at an angle to the vertical direction. In this case, the storage box 42b should be installed taking into account the gas spray direction of the spray nozzle 42a.

The non-defective product recovery device 43 has a gas blowing section 43a and a storage box (recovery box) 43b. This non-defective product recovery device 43 is located downstream in the conveying direction A2 from the position where the reusable product recovery device 42 is located, and the gas blowing section 43a is provided in common for each conveying path P.

The gas blowing section 43a is provided at the end of the conveying device 31 of the second printing device 30, i.e., at the end of the lower horizontal portion of the conveying belt 31a. For example, during the printing process, the gas blowing section 43a constantly blows gas (e.g., air) toward the conveying belt 31a, causing the tablets T to fall from the conveying belt 31a. At this time, the gas blown out from the gas blowing section 43a passes through suction holes (similar to suction holes 21g shown in Figure 2) in the conveying belt 31a and hits the tablets T. The gas blowing section 43a can be, for example, an air blower with a slit-shaped opening extending in a direction intersecting (e.g., perpendicular to) the conveying direction A2 in the horizontal plane. The gas blowing section 43a is electrically connected to the control device 50, and its operation is controlled by the control device 50.

Here, tablets T that have passed through the defective product recovery device 41 and the reusable product recovery device 42 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 driven pulley 31c side. At this position, the suction effect on the tablets T ceases, and gas is blown onto the tablets T from above by the gas blowing section 43a, causing the tablets T to fall from the conveyor belt 31a. By providing the gas blowing section 43a, tablets T are reliably allowed to fall from the conveyor belt 31a and towards the storage boxes 43b.

The control device 50 includes an image processing unit 51, a printing processing unit 52, an inspection processing unit (inspection unit) 53, and a memory unit 54. The image processing unit 51 processes images. The printing processing unit 52 performs printing-related processing. The inspection processing unit 53 performs inspection-related processing. 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, the second printing device 30, and the collection device 40, and also receives position information of tablets T transmitted from the individual detection devices 22 and 32 of the first printing device 20 and the second printing device 30, images transmitted from the individual imaging devices 23, 25, 33, and 35 of the first printing device 20 and the second printing device 30, the side imaging cameras SC1 of the first side image acquisition units SD1 and second side image acquisition units SD2, and the three-dimensional image imaging cameras C1 of the first three-dimensional image acquisition units 3D1 and second three-dimensional image acquisition units 3D2. The operating conditions are set in advance and stored in the memory unit 54. The control device 50 controls each processing unit and the recovery device 40 based on the operating conditions stored in the memory unit 54.

Next, the print processing unit 52, the inspection processing unit 53, and the collection operation of the collection device 40 will be described. The image processing unit 51 processes images of tablets T captured by the first imaging devices 23, 33, the second imaging devices 25, 35, the first side image acquisition unit SD1, the second side image acquisition unit SD2, the first three-dimensional image acquisition unit 3D1, and the second three-dimensional image acquisition unit 3D2, and sends them to the inspection processing unit 53. The inspection processing unit 53 uses these images to detect tablets T that have been deemed defective due to printing defects or due to visual defects. The defective product collection device 41 collects tablets T that have been deemed "defective" by the inspection processing unit 53. Of these, tablets T that have been detected as "defective" upstream of the print head device 24 on the transport path P (i.e., based on images captured by the first imaging device 23 and the first side image acquisition unit SD1) are collected by the defective product collection device 41 without being printed by the print head device 24. Similarly, if a defect is detected by the first imaging device 23, printing is not performed by the print head device 34 and the tablets are collected by the defective product collection device 41. The reused product collection device 42 collects tablets T that are not cracked, chipped, or soiled but for which printing was not performed due to reasons such as poor tablet posture. The posture of the tablets T is determined by the inspection processing unit 53 based on images captured by the first imaging device 23, first side image acquisition unit SD1, or other devices upstream of the print head device 24 on the conveying path P. In the defective product collection device 41 and reused product collection device 42, the tablets are collected into a defective product collection box 41b and a reused product collection box 42b by spray nozzles 41a and 42a, respectively, and tablets T not collected here are collected into a non-defective product collection box 43b.

(Printing process)
Next, we will explain the printing process and inspection process performed by the above-mentioned tablet printing device 1. In the following printing process, we will explain double-sided printing, in which identification information is printed on both sides of a tablet T that has a score line formed on one side so that it is aligned with the score line (for example, parallel to the extension direction of the score line).

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 alignment feeder 12, which then arranges them in two rows and moves them. The tablets T moving in these two rows are then sequentially supplied to the conveyor belt 21a of the first printing device 20 by the delivery feeder 13. The conveyor belt 21a rotates in the conveying direction A1 due to the rotation of the drive pulley 21b and each driven pulley 21c driven by the motor 21d. Therefore, the tablets T supplied to the conveyor belt 21a are conveyed in two rows on the conveyor belt 21a at a predetermined moving speed. The conveyor belt 31a also rotates in the conveying direction A2 due to the rotation of the drive pulley 31b and each driven pulley 31c driven by the motor 31d.

In the first printing device 20, tablets T are suction-held on the conveyor belt 21a, and the detection device 22 detects the tablets T on the conveyor belt 21a. As a result, position information of the tablets T (position in the conveying direction A1) is acquired and input to the control device 50. This position information of the tablets T is stored in the memory unit 54 and used in post-processing. Next, the tablets T on the conveyor belt 21a are imaged by the first imaging device 23 at a timing based on the position information of the tablets T described above, and the captured images are sent to the control device 50. Based on each image sent from the first imaging device 23, positional deviation information of the tablets T (e.g., positional deviation of the tablets T in the X, Y, and θ directions in Figure 2) is generated by the image processing unit 51 and stored in the memory unit 54. Based on this positional deviation information of the tablets T, printing conditions for the tablets T (such as ink ejection position and ejection speed) are set by the print processing unit 52 and stored in the memory unit 54.

Next, the tablets T on the conveyor belt 21a are imaged by the side-image capturing camera SC1 of the first side-image capturing unit SD1. As shown in Figures 3A and 3B, the first side-image capturing unit SD1 is illuminated by a ring light R. Light reflected from the side of the tablet T is incident on the first reflecting mirror M1, the light reflected by the first reflecting mirror M1 is incident on the second reflecting mirror M2, and the light reflected by the second reflecting mirror M2 passes through a lens (not shown) and enters the side-image capturing camera SC1, capturing an image of the side of the tablet T. The side-image of the tablet T captured by the side-image capturing camera SC1 is transmitted to the control device 50. As shown in Figure 3B, eight first reflecting mirrors M1 and eight second reflecting mirrors M2 are arranged (the number of mirrors is not limited to eight and may be more or less than this). In other words, the side-image capturing camera SC1 captures images of the side of the tablet T from eight directions as a single image. The side image captured by the side imaging camera SC1 and sent to the control device 50 is processed by the image processing unit 51, and the inspection processing unit 53 determines whether the tablet is defective. As a result, tablets T that are determined to be good products undergo subsequent printing processing, while tablets that are determined to be defective are collected by the defective product collection device 41 without undergoing further printing processing.

Next, each tablet T on the conveyor belt 21a is printed by the print head device 24 based on the print data and printing conditions described above, at a timing based on the position information of the tablet T described above, i.e., when the tablet T arrives below the print head device 24. Ink is ejected appropriately from each nozzle 24b in each print head 24a of the print head device 24, 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, aligned with the score line (e.g., parallel to the extension direction of the score line).

The tablets T with the printed identification information are imaged by the second imaging device 25 at a timing based on the position information of the tablets T described above, and the captured images are 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 quality of each tablet T (whether the tablet T is a good product or not) and inspection result information indicating the print quality of each tablet T and the appearance, such as cracks and chips, is stored in the memory unit 54. For example, the inspection processing unit 53 determines whether the printing pattern is printed in a predetermined pattern at a predetermined position on the tablet T. Tablets T that are determined to have the printing pattern printed in a predetermined pattern at a predetermined position on the tablet T are deemed to be good tablets T that have passed inspection, and the subsequent printing process continues.

Then, the external shape of the tablet T is imaged by the three-dimensional image capturing camera C1 of the first three-dimensional image acquisition unit 3D1. The image captured by the three-dimensional image capturing camera C1 is sent to the control device 50, where it is processed by the image processing unit 51 to generate a three-dimensional image. Based on this image, the inspection processing unit 53 determines whether the tablet is defective. As a result, tablets T that are determined to be good undergo subsequent printing processing, while tablets that are determined to be defective are collected by the defective product collection device 41 without further printing processing.

After passing through the first 3D image acquisition unit 3D1, the tablet T is transported along with the movement of the conveyor belt 21a and passes above the drying device 26, which is in the drying operation. At this time, the ink that reaches (lands on) the tablet T is dried by the drying device 26 as the tablet T passes above it, 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 on the tablet T ceases to act, and the tablet T is released from its position on the underside of the conveyor belt 21a and is passed from the first printing device 20 to the second printing device 30.

In the second printing device 30, tablets T are also suction-held on the conveyor belt 31a, and the printing and inspection processes are carried out in the same manner as described above. However, in the second printing device 30, after being imaged by the second imaging device 35, tablets T pass through the second 3D image acquisition unit 3D2 and the second side image acquisition unit SD2 in that order. Tablets T are transported along the movement of the conveyor belt 31a and pass above the drying device 36, which is in drying operation. Tablets T with dried ink then reach the defective product collection device 41. At this position, tablets T other than good ones (defective or unknown) fall from the underside of the conveyor belt 31a due to the gas spray (blowing) from the spray nozzle 41a and are collected in the storage box 41b. Tablets T that could not be printed due to poor posture or other reasons are collected in the reused product collection device 42. Good tablets T (i.e., tablets T not collected by the defective product collection device 41 or the reusable product collection device 42) pass through the defective product collection device 41 and the reusable product collection device 42 and reach a position near the end of the conveyor belt 31a on the driven pulley 31c side. At this position, the suction action no longer acts on the tablets T, and they fall. Furthermore, gas is blown onto the tablets T from above by the gas blowing section 43a, so the tablets T fall reliably from the conveyor belt 31a. The tablets T that fall from the conveyor belt 31a are collected in a storage box 43b.

(Side inspection)
Here, the side surface inspection of the tablet T will be described. First, in the first printing device 20, before printing is performed by the print head device 24, the first side surface image acquisition unit SD1 performs side surface inspection of the tablet T. The side surface inspection here determines whether there is dirt, chipping, cracks, etc. on the side of the tablet T (by the inspection processing unit 53). If the inspection processing unit 53 determines that there is dirt, chipping, or cracking, the tablet T is determined to be a defective product, and printing is not performed by the print head device 24 and the print head device 34 of the second printing device 30, and the tablet T is collected as a defective product by the defective product collection device 41. In other words, by inspecting the side surface of the tablet T before printing processing, unnecessary ink consumption can be eliminated.

Next, in the second printing device 30, after printing is performed by the print head device 34, the second side image acquisition unit SD2 performs side inspection of the tablet T. This side inspection checks for stains, chips, and cracks on the side of the tablet T, including ink stains that adhere to the tablet T as it passes through the print head devices 24 and 34. In rare cases, ink may splatter and adhere to the side of the tablet T as it passes through the print head devices 24 and 34. By performing side inspection of the tablet T after it passes through the print head device 34, it is possible to inspect for such stains as well. Furthermore, as shown in FIG. 5, the second side image acquisition unit SD2 of the second printing device 30 images the side of the tablet T that is suction-held on the curved portion of the conveyor belt 31a (the curved portion of the drive pulley 31a). Therefore, unlike the imaging performed by the first side image acquisition unit SD1 of the first printing device 20, it is possible to inspect the edge of the tablet T on the surface that contacts the conveyor belt 31a. The edges of tablets are the parts most susceptible to chipping, and chipping can occur when tablets collide with other tablets or with other components of the tablet printing device 1 during transport. However, the second side image acquisition unit SD2 can inspect the sides, including the edge portions, of both sides of tablets T that have been transported through each part of the tablet printing device 1.

(3D inspection)
The first 3D image acquisition unit 3D1 and the second 3D image acquisition unit 3D2 are provided on the side wall side of the housing B of the tablet printing device 1. That is, they are provided in a position that will not interfere with other components when a mechanism for dissipating heat from the side wall side to 3D1 and 3D2 is attached. As described above, the first 3D image acquisition unit 3D1 and the second 3D image acquisition unit 3D2 are constantly irradiated with laser light from the laser light irradiation units L1 and L2 during device operation in order to perform inspection using the light cutting method, and are among the components of the tablet printing device 1 that are most susceptible to heat generation. Print head devices 24 and 34 are provided within the tablet printing device 1, and the print heads 24 and 34 may malfunction and become unusable if the temperature inside the device exceeds 30 degrees. Furthermore, the viscosity of the ink supplied to the print heads 24 and 34 decreases as the temperature inside the tablet printing device 1 increases, resulting in poor ejection (ejection of more ink than specified), which can cause poor printing on the tablets T. By providing the first 3D image acquisition unit 3D1 and the second 3D image acquisition unit 3D2 on the side wall of the housing B, heat can be easily dissipated outside the device, preventing malfunctions of the print heads 24 and 34 and preventing printing defects. For example, a cooling fan CF1 (cooling means) is provided downstream of the first 3D image acquisition unit 3D1 in the transport direction A1 (on the right side of the drawing) in FIG. 1 , and supplies cooling air supplied from outside the side wall W1 to the first 3D image acquisition unit 3D1. A cooling fan CF2 (cooling means) is also provided downstream of the 3D image acquisition unit 3D2 in the transport direction A2 (on the left side of the drawing) above the second side image acquisition unit SD2, and supplies cooling air from outside the side wall W2 to the second 3D image acquisition unit 3D2. By providing the first 3D image acquisition unit 3D1 and the second 3D image acquisition unit 3D2 on the side walls W1 and W2 in this manner, compared to, for example, a case where the first 3D image acquisition unit 3D1 is provided upstream of the print head device 24 in the transport direction A1, the cooling air can be prevented from being heated before being supplied to the first 3D image acquisition unit 3D1, which is the cooling target, thereby improving cooling efficiency. Similarly, compared to a case where the 3D image acquisition unit 3D2 is provided upstream of the print head device 34 in the transport direction A2, the cooling air can be prevented from being heated before being supplied to the second 3D image acquisition unit 3D2, which is the cooling target, thereby improving cooling efficiency. In other words, only the cooling fan CF1 is provided in the area between the first 3D image acquisition unit 3D1 and the side wall W1, which is the side wall of the housing B closer to the first 3D image acquisition unit 3D1 (the side wall on the right side of the paper surface of FIG. 1 of the two side walls facing each other in the transport direction A1). Other components (particularly the print head 24) are provided outside this area (in an area upstream of the three-dimensional image acquisition unit 3D1). Similarly, with the second three-dimensional image acquisition unit 3D2, components such as the print head 34 are not provided in the area between the sidewall W2 (the sidewall on the left side of the paper in FIG. 1 of the two sidewalls facing each other in the conveying direction A1) of the housing B closer to the three-dimensional image acquisition unit 3D2, but instead, a cooling fan CF2 and a second side image acquisition unit SD2 are provided. The second side image acquisition unit SD2 is provided in a position (below the cooling fan CF2) where it does not interfere with the sidewall W2 and the three-dimensional image acquisition unit 3D2.

Furthermore, the first three-dimensional image acquisition unit 3D1 is located downstream of the print head 24, and the second three-dimensional image acquisition unit 3D2 is located downstream of the print head 34, both of which are located to face the tablets T being transported on a horizontal plane. As a result, even if the tablets T collide with the print heads 24, 34 as they pass below them, causing chipping or cracking, the first three-dimensional image acquisition unit 3D1 and the second three-dimensional image acquisition unit 3D2 can detect this and eject the tablets as defective. Furthermore, because the tablets T are detected as they are transported on a horizontal plane, their three-dimensional shapes can be accurately detected.

If the nozzle 24b of the print head device 24 dries, the ink near the nozzle 24b may dry and solidify, leading to ejection problems. To prevent this, the suction force applied to the suction holes 21g on the conveyor belt 21a facing the print head device 24 may be reduced to prevent the nozzle 24b from being affected by airflow. For example, a shielding plate that blocks part of the suction holes 21g is provided on the upper surface of the suction chamber 21f to reduce the suction force acting below the print head device 24. Since the suction force applied to tablets T conveyed through this area is reduced, strong suction force is not applied to a portion of the tablets T, reducing the likelihood that tablets T with an R-shape will be held in an upright position. It is preferable that the area where suction force is reduced includes not only the area directly below the print head device 24 but also the area from the detection device 22 to below the first 3D image acquisition unit 3D1. This enables detection, imaging, and printing of tablets T while maintaining the same orientation. Furthermore, the first three-dimensional image acquisition unit 3D1 can also prevent the tablet T from assuming the upright position described above, allowing the external shape of the tablet T to be accurately acquired.

As described above, according to the first embodiment, the first side image acquisition unit SD1, the second side image acquisition unit SD2, the first three-dimensional image acquisition unit 3D1, and the second three-dimensional image acquisition unit 3D2 are each provided in appropriate positions, enabling successful visual inspection and printing inspection of tablets.

Second Embodiment
The second embodiment will be described with reference to Fig. 6. Note that in the second embodiment, differences from the first embodiment (the position of the three-dimensional image acquisition unit and the presence or absence of a cooling fan) will be described, and other descriptions will be omitted.

As shown in FIG. 6 , in the second embodiment, the first 3D image acquisition unit 3D1 and the second 3D image acquisition unit 3D2 are provided below the first conveying device 21 and the second conveying device 31, respectively. By providing the 3D image acquisition units below the conveying devices in this way, heat generated by the 3D image acquisition units can be prevented from reaching the print head device. For example, the first printing device 20 and the second printing device 30 are provided as close as possible to each other so that the distance between them is approximately 0.2 mm above the tablet thickness in the vertical direction in order to transfer tablets T, which are approximately 2 to 3 mm thick, without causing cracks or chips. In other words, within the housing B, the passage of most airflow between the left and right sides of the page in FIG. 6 is blocked by the portion where tablets T are transferred between the first printing device 20 and the second printing device 30. Therefore, heat generated by the first 3D image acquisition unit 3D1 can be prevented from reaching the print head device 34.

Furthermore, the drying devices 26, 36 can also serve as both a drying device for drying the ink on the tablets T and a cooling means for the three-dimensional image acquisition unit. For example, the drying device 26 is provided upstream of the first three-dimensional image acquisition unit 3D1 in the conveying direction A1, and cool air is supplied from this drying device 26. The cool air from the drying device 26 is supplied toward the conveyor belt 21a and the first three-dimensional image acquisition unit 3D1 located downstream. The drying device 36 of the second conveying device 31 also supplies cool air toward the conveyor belt 31a and the second three-dimensional image acquisition unit 3D2 located downstream in the conveying direction A2.

As described above, the second embodiment can achieve the same effects as the first embodiment. Furthermore, since the drying devices 26 and 36 can serve both as drying devices for drying the tablets T and as cooling means for the first three-dimensional image acquisition unit 3D1 and the second three-dimensional image acquisition unit 3D2, the three-dimensional image acquisition units can be cooled without the need for additional cooling fans.

<Other Embodiments>
In the above description, an example in which the tablets T are transported in two rows has been given, but this is not limited thereto, and the number of rows may be one, three, four or more, and the number of transport paths P and the number of transport belts 21a, 31a are not particularly limited. Furthermore, the shape of the suction holes 21g of the transport belts 21a, 31a is not particularly limited either.

In addition, while the above explanation exemplifies providing a print head 24a for each transport path P, this is not limited to this; for example, one print head 24a may be used to print on two or more rows of tablets T.

In addition, in the above explanation, a print head with nozzles 24b arranged in a single row was used as an example of the inkjet print head 24a, but this is not limited to this. For example, a print head with nozzles 24b arranged in multiple rows may also be used. Furthermore, multiple print heads 24a may also be arranged in the transport direction A1.

Furthermore, while the above description exemplifies the provision of drying devices 26 and 36, the number of drying devices is not limited. For example, only drying device 26 or drying device 36, or neither drying device 26 nor 36, may be provided.

Furthermore, in the above explanation, the second side image acquisition unit SD2 is illustrated as being located downstream of the second three-dimensional image acquisition unit 3D2, but this is not limited to this, and the side image acquisition unit may be arranged first, followed by the three-dimensional image acquisition unit, as in the first printing device 20.

In addition, the above explanation exemplifies the detection of cracks and chips by the first imaging devices 23, 33 and the first side image acquisition unit SD1, but this is not limited to this. Alternatively, cracks and chips may be detected by a three-dimensional image acquisition unit downstream of the print head devices 24, 34, and the first imaging devices 23, 33 and the first side image acquisition unit SD1 may perform processing to detect only dirt on the tablets.

In addition, in the above explanation, the first three-dimensional image acquisition unit 3D1 and the second three-dimensional image acquisition unit 3D2 are illustrated as being arranged so that their horizontal surfaces face the tablets T being transported, but this is not limited thereto, and they may also be arranged so that their curved surfaces face the tablets T being transported.

In addition, in the above explanation, the three-dimensional image capturing camera C1 is illustrated as being located downstream of the laser light irradiation unit L1 in the conveying direction A1, but this is not a limitation and it may also be located upstream.

In addition, in the above explanation, an example was given in which the side image acquisition unit SD2 in the second printing device 30 is additionally provided with a third reflecting mirror M3 with 90-degree polarization and a side image capturing camera SC1 polarized at 90 degrees, but this is not limited to this. For example, the third reflecting mirror M3 may be omitted, and the side image capturing camera SC1 may be provided in the optical path of the first reflecting mirror M1 and the second reflecting mirror M2.

Furthermore, in the above explanation, an example of a method for cooling the first three-dimensional image acquisition unit 3D1 and the second three-dimensional image acquisition unit 3D2 is to supply cooling air from outside the side walls W1, W2 and supply it to the three-dimensional image acquisition units 3D1, 3D2 by a cooling fan. However, this is not limited to this. For example, air may be blown onto the three-dimensional image acquisition units 3D1, 3D2 from the top surface of the tablet printing device 1, and heat may be discharged along with the air to the outside from the side walls W1, W2. Furthermore, the cooling means may be attached to a part other than the wall surface (for example, the interior of the tablet printing device 1).

In addition, the above explanation has been given of an example in which the first printing device 20 and the second printing device 30 are stacked one on top of the other to print on both sides or one side of the tablets T, but this is not limited to this. For example, it is also possible to provide only the first printing device 20 and print on only one side of the tablets T.

In addition, while the above description illustrates an example in which the reusable product collection device 42 is installed downstream of the defective product collection device 41, this is not limited to this and the reusable product collection device 42 may also be installed upstream of the defective product collection device 41.

In addition, although the above description does not specifically mention the suction force of the suction chambers 21f and 31f, the suction force may be reduced only near the nozzles of the print head devices 24 and 34 to prevent them from drying out. When changing the suction force in this manner, it is preferable to maintain the same suction force from the detection device 22 to the first three-dimensional image acquisition unit 3D1 to avoid changing the transport position of the tablet T, which could interfere with accurate printing or inspection. Similarly, in the second printing device 30, it is preferable to maintain the same suction force from the detection device 32 to the second three-dimensional image acquisition unit 3D2. Note that the second side image acquisition unit must apply a suction force to the tablet T that is strong enough to counter the centrifugal force of the pulley 31b, and therefore the suction force must be stronger than the suction force reduced below the print head device 34.

Furthermore, in the above description, the tablet printing device 1 is entirely enclosed by the housing B, but this is not limited to this; for example, a portion, such as a collection box, may be located outside the housing B.

The aforementioned tablets T can include tablets used for pharmaceutical, edible, cleaning, industrial, or aromatic purposes. Tablets include plain tablets, sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-coated tablets, multi-layered tablets, and dry-coated tablets, and can also include various types of capsule tablets such as hard capsules and soft capsules. Tablet shapes include discs, lenses, triangles, and ovals. When the tablets to be printed are for pharmaceutical or edible use, edible ink is preferred. This edible ink can be any of synthetic pigment ink, natural pigment ink, dye ink, and pigment ink.

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 may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

1 Tablet printing device SD1 First side image acquisition unit SD2 Second side image acquisition unit 3D1 First three-dimensional image acquisition unit 3D2 Second three-dimensional image acquisition unit 31a Conveyor belt 34 Print head device 41 Defective product recovery device 42 Re-inspection product recovery device 42b Storage box 43 Non-defective product recovery device 50 Control device (control unit)
51 Image processing unit 53 Inspection processing unit (inspection unit)
CF1, CF2 Cooling Fan T Tablet

Claims (2)

A tablet printing device is enclosed in a rectangular housing and prints identification information on tablets by ejecting ink from a print head device onto the tablets .
a supply device for supplying the tablets;
a first printing device that conveys the tablets supplied from the supply device by a first conveyor belt and performs a printing process on one side of the tablets;
a second printing device that conveys the tablet received from the first printing device by a second conveyor belt and performs printing processing on the other side of the tablet;
and
The housing includes a first side wall and a second side wall that face each other in a conveying direction of the tablets by the first conveyor belt,
the supply device and the second printing device are provided on the first side wall side so as to be aligned vertically,
the first printing device is provided on the second sidewall at a higher position than the second printing device,
the first printing device has a first print head device that prints on the one side of the tablet, and a first three- dimensional image acquisition unit that is provided between the first print head device and the second side wall and that acquires a three-dimensional image of the tablet printed by the first print head device;
The second printing device has a second print head device that prints on the other side of the tablet, and a second three-dimensional image acquisition unit that is provided between the second print head device and the first side wall and that acquires a three-dimensional image of the tablet printed by the second print head device,
the first three-dimensional image acquisition unit and the second three-dimensional image acquisition unit each have a laser light irradiation unit and a three-dimensional image capturing camera;
a control device that controls the first print head device, the second print head device, the first three-dimensional image acquisition unit, and the second three-dimensional image acquisition unit;
The control device processes the three-dimensional images obtained by the first three-dimensional image acquisition unit and the second three-dimensional image acquisition unit, and performs an appearance inspection of the tablet,
a first cooling unit provided on the second side wall and configured to supply gas to the first three-dimensional image acquisition unit;
A tablet printing apparatus having a second cooling means provided on the first side wall and supplying gas to the second three-dimensional image acquisition unit . a first side image acquisition unit that acquires an image of the side of the tablet upstream of the first print head device;
a second side image acquisition unit that acquires an image of the side of the tablet downstream of the second print head device;
a recovery device that recovers the tablets downstream of the second side image acquisition unit,
The tablet printing device described in claim 1, characterized in that the control device inspects the appearance of the tablet based on the images acquired by the first side image acquisition unit and the second side image acquisition unit, controls printing by the first print head based on the inspection results of the image acquired by the first side image acquisition unit, and controls collection by the collection device based on the inspection results of the image acquired by the second side image acquisition unit.