Tablet printer and tablet printing method

Abstract

To provide a tablet printer and a tablet printing method capable of suppressing printing failure.SOLUTION: A tablet printer in an embodiment comprises: a transport device (for example, transport part 21) for transporting a tablet; a first inkjet head (for example, inkjet head 24) for printing to the tablet; a movement mechanism (for example, second movement mechanism 24A) for moving the transport device or the first inkjet head in a height direction; and a control device 40 controlling the movement mechanism. The control device 40 generates a first correction value on the basis of a difference between a height position of the transport device and a first reference height position (for example, reference height position Ba), generates a second correction value on the basis of tablet kind information related to a kind of the tablet, and then controls the movement mechanism on the basis of the first and second correction values.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] There are tablet printing devices that print on tablets using an inkjet head. For these tablet printing devices, a conveyor mechanism has been developed in which a conveyor belt is looped around multiple pulleys and tablets are placed on the conveyor belt for conveyance. Suction holes are usually provided in the conveyor belt, and the tablets are sucked and held through the suction holes by the suction force of a suction chamber provided inside the conveyor belt.

[0003] The conveyor belt needs to be replaced when it wears out due to aging, etc. When the conveyor belt is replaced, the distance from the conveyor belt to the inkjet head may change slightly due to individual differences in the conveyor belt (the former case), and when the tablets are conveyed by transferring between multiple conveyor mechanisms, the distance between the conveyor belts before and after the transfer may change (the latter case).

[0004] In the former case, printing defects may occur when the ink ejected from the inkjet head does not land properly on the tablets on the conveyor belt, or when the tablets on the conveyor belt collide with the inkjet head.In the latter case, tablets may not be transferred properly between the conveyor mechanisms, causing them to fall, or when the tablets are misaligned due to the transfer of tablets, changing the positional relationship between the suction holes in the conveyor belt and the tablets, preventing stable conveyance of the tablets (for example, the tablets may become unstable and shake), resulting in printing defects. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-58220 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a tablet printing device and a tablet printing method that can reduce printing defects. [Means for solving the problem]

[0007] A tablet printing device according to an embodiment of the present invention comprises a conveying device for conveying tablets, a first inkjet head for printing on the tablets, a moving mechanism for moving the conveying device or the first inkjet head in a vertical direction, and a control device for controlling the moving mechanism, wherein the control device generates a first correction value based on the difference between the height position of the conveying device and a first reference height position, generates a second correction value based on tablet variety information relating to the variety of the tablet, and controls the moving mechanism based on the first correction value and the second correction value.

[0008] A tablet printing method according to an embodiment of the present invention includes a control device generating a first correction value based on the difference between the height position of a conveying device that conveys tablets and a first reference height position, generating a second correction value based on tablet variety information relating to the variety of the tablets, and controlling a movement mechanism that moves the conveying device or a first inkjet head that prints on the tablets in the vertical direction based on the first correction value and the second correction value. [Effects of the Invention]

[0009] According to an embodiment of the present invention, printing defects can be reduced. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a tablet printing apparatus according to an embodiment of the present invention. [Figure 2] 1 is a plan view illustrating an example of a schematic configuration of a printing apparatus according to an embodiment of the present invention. [Figure 3]FIG. 1 is a diagram illustrating an example of a schematic configuration of a movement mechanism according to an embodiment of the present invention. [Figure 4] FIG. 1 is a diagram illustrating an example of a schematic configuration of a control device according to an embodiment of the present invention. [Figure 5] 10 is a flowchart showing an example of the flow of a position adjustment process according to the embodiment of the present invention. [Figure 6] FIG. 4 is a diagram illustrating an example of a correction table according to an embodiment of the present invention. [Figure 7] FIG. 10 is a plan view showing a first modified example of the configuration of the detection section according to the embodiment of the present invention. [Figure 8] FIG. 10 is a plan view showing a second modified example of the configuration of the detection unit according to the embodiment of the present invention. [Figure 9] FIG. 10 is a plan view showing a third modified example of the configuration of the detection unit according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment> This embodiment will be described with reference to FIGS.

[0012] (Example of tablet printing device configuration) As shown in FIG. 1, the tablet printing apparatus 1 according to this embodiment includes a supplying device 10, a first printing device 20, a second printing device 50, a collecting device 30, and a control device 40.

[0013] The supply device 10 has a hopper 11, an alignment feeder 12, and a delivery feeder 13. This supply device 10 is positioned on one end side of the first printing device 20, and is configured to be able to supply tablets T, which are printing objects, to the first printing device 20. The delivery feeder 13 functions as a supply conveying section (conveying device).

[0014] The hopper 11 stores a large number of tablets T and sequentially supplies the stored tablets T to the alignment feeder 12. The alignment feeder 12 aligns the supplied tablets T in a line and transports them in a conveying direction A1 (clockwise direction) toward the delivery feeder 13. As the alignment feeder 12, for example, a belt conveying mechanism or a vibrating feeder is used. The delivery feeder 13 sequentially sucks in and holds each of the tablets T lined up in a line on the alignment feeder 12 from above the tablets T, transports the held tablets T in a line to the first printing device 20, and delivers them to the first printing device 20. As the delivery feeder 13, for example, a belt conveying mechanism is used. The belt conveying mechanism of the delivery feeder 13 rotates in a conveying direction A2 (counterclockwise direction). The supply device 10 is electrically connected to the control device 40, and its driving is controlled by the control device 40.

[0015] The first printing device 20 includes a transport unit 21, a detection unit 22, a first imaging unit 23, an inkjet head 24, a second imaging unit 25, and a drying unit 27. The transport unit 21 functions as a first transport unit (transport device). The inkjet head 24 functions as a first inkjet head.

[0016] The conveying unit 21 includes a conveying belt 21a, a driving pulley 21b, a plurality of driven pulleys 21c, a motor 21d, a position detector 21e, and a suction chamber 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 main body (not shown), and the driving pulley 21b is connected to the motor 21d. The motor 21d is electrically connected to the control device 40, and its driving is controlled by the control device 40. 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 40, and transmits a detection signal to the control device 40. The conveying unit 21 causes the conveying belt 21a to run together with the driven pulleys 21c by rotating the driving pulley 21b by the motor 21d, and conveys the tablets T on the conveying belt 21a in a conveying direction A1 (clockwise direction).

[0017] As shown in FIG. 2, a plurality of circular suction holes 21g are formed in the conveyor belt 21a. Each of these suction holes 21g is a through-hole that adsorbs a tablet T and is aligned in a row along the conveying direction A1 to form a single conveying path. Each suction hole 21g is connected to the inside of the suction chamber 21f (see FIG. 1) via a suction path (not shown) formed in the suction chamber 21f, enabling suction force to be obtained by the suction chamber 21f. A pump is connected to the suction chamber 21f via a suction pipe (not shown), and operation of the pump reduces the pressure inside the suction chamber 21f. 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 pump is electrically connected to the control device 40, and its operation is controlled by the control device 40. When the pressure inside the suction chamber 21f is reduced, the tablet T placed on each suction hole 21g of the conveyor belt 21a is sucked through the suction hole 21g and held on the conveyor belt 21a.

[0018] The detection unit 22 is positioned downstream in the conveying direction A1 from the position where the supply device 10 is provided, and is provided above the conveying path where each suction hole 21g is lined up. This detection unit 22 detects the tablet T that has reached the detection position directly below the detection unit 22 (arrival of tablet T), i.e., the position of the tablet T on the conveyor belt 21a in the conveying direction A1, by emitting and receiving laser light. As the detection unit 22, for example, a displacement sensor is used. Also, various laser sensors such as a reflective laser sensor are used as the displacement sensor. The detection unit 22 is electrically connected to the control device 40, and transmits a detection signal to the control device 40.

[0019] The first imaging unit 23 is positioned downstream in the conveying direction A1 from the position where the detection unit 22 is provided, and is provided above the conveying path in which each suction hole 21g is lined up. Based on the position information of the tablet T in the conveying direction A1 detected by the detection unit 22, the first imaging unit 23 performs imaging at the first imaging timing when the tablet T reaches the imaging position directly below the first imaging unit 23, acquires a first image including the upper surface of the tablet T, and transmits the acquired first image to the control device 40. The first image is used to detect the position of the tablet T in the X direction, Y direction, and θ direction (see FIG. 2). As the first imaging unit 23, various cameras having imaging elements such as a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor) are used. The first imaging unit 23 is electrically connected to the control device 40, and its operation is controlled by the control device 40. Incidentally, illumination for imaging is also provided as necessary.

[0020] 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 first imaging unit 23. Furthermore, the position in the θ direction is, for example, a position indicating the degree of rotation of the tablet T in a horizontal plane along the XY plane of the imaging area of ​​the first imaging unit 23. This position in the θ direction is detected when the tablet T has a directional shape, such as when a score line is provided on the tablet T or when the tablet T is molded into an oval, elliptical, triangular, rectangular, or other shape. Note that the X and Y directions are positions in the horizontal direction.

[0021] The inkjet head 24 is positioned downstream in the transport direction A1 from the position where the first imaging unit 23 is provided, and is provided above the transport path in which the suction holes 21g are aligned. The inkjet head 24 has a plurality of nozzles 24a (e.g., several hundred to several thousand) (see FIG. 2 ), and is provided so that the direction in which the nozzles 24a are aligned (nozzle row) intersects, for example, perpendicular to, the transport direction A1 in a horizontal plane. The inkjet head 24 ejects ink individually from each nozzle 24a by operating a drive element for each nozzle 24a. The inkjet head 24 may be any of various inkjet print heads having drive elements such as piezoelectric elements, heat generating elements, or magnetostrictive elements. The inkjet head 24 is electrically connected to a control device 40, and its drive is controlled by the control device 40.

[0022] The second imaging unit 25 is positioned downstream in the conveying direction A1 from the position where the inkjet head 24 is provided, and is provided above the conveying path in which each suction hole 21g is lined up. Based on the position information of the tablet T in the conveying direction A1 detected by the detection unit 22, the second imaging unit 25 performs an image capture at the second imaging timing when the tablet T reaches the imaging position directly below the second imaging unit 25, acquires a second image including the upper surface of the tablet T, and transmits the acquired second image to the control device 40. The second image is used to inspect the print pattern printed on the tablet T. As with the first imaging unit 23 described above, various cameras having imaging elements such as CCD or CMOS are used as the second imaging unit 25. The second imaging unit 25 is electrically connected to the control device 40, and its operation is controlled by the control device 40. Illumination for imaging is also provided as necessary.

[0023] The drying unit 27 is disposed opposite the conveyor belt 21a, and is provided, for example, below the conveyor unit 21. This drying unit 27 dries the ink applied to each tablet T on the conveyor belt 21a. As the drying unit 27, various dryers are used, such as a blower that dries using a gas such as air, a heater that dries using radiant heat, or a blower that dries using warm air or hot air using both a gas and a heater. The drying unit 27 is electrically connected to the control device 40, and its operation is controlled by the control device 40.

[0024] Here, the first printing device 20 and the second printing device 50 are arranged such that the conveying section 21 and the conveying section 51 overlap one another, and the tablets T printed by the upper first printing device 20 are transferred to the lower second printing device 50, where both sides of the tablets T are printed. For example, to ensure smooth transfer of the tablets T from the first printing device 20 to the second printing device 50, the conveying speed of the first printing device 20 and the conveying speed of the second printing device 50 are always the same.

[0025] The second printing apparatus 50 has the same structure as the first printing apparatus 20. That is, the second printing apparatus 50 includes a conveying unit 51, a detecting unit 52, a first imaging unit 53, an inkjet head 54, a second imaging unit 55, and a drying unit 57. The conveying unit 51 includes a conveying belt 51a, a driving pulley 51b, multiple driven pulleys 51c, a motor 51d, a position detector 51e, and a suction chamber 51f. The conveying unit 51 conveys tablets T on the conveying belt 51a in a conveying direction A2 (counterclockwise direction). The conveying unit 51 functions as a second conveying unit (conveying device). The inkjet head 54 functions as a first inkjet head or a second inkjet head. Note that the elements constituting the second printing apparatus 50 have basically the same structure as the elements constituting the first printing apparatus 20, and therefore, description thereof will be omitted.

[0026] The recovery device 30 is positioned downstream in the conveying direction A2 from the position where the drying section 57 is provided, and is provided below the conveying section 51. This recovery device 30 has a reusable product recovery section 31, a defective product recovery section 32, and a non-defective product recovery section 33. The recovery device 30 recovers reusable tablets T using the reusable product recovery section 31, recovers defective tablets T using the defective product recovery section 32, and recovers non-defective tablets T using the non-defective product recovery section 33. For example, reusable products are reusable tablets and non-printed tablets that are undamaged and free of foreign matter. Furthermore, defective products include non-printed tablets with foreign matter attached and tablets that fail printing (printed tablets) that are undamaged and free of foreign matter attached, and non-defective products are tablets that pass printing (printed tablets) that are undamaged and free of foreign matter attached. The arrangement order of the reusable product recovery section 31, the defective product recovery section 32, and the non-defective product recovery section 33 in the conveying direction A2 is not limited to the order shown in FIG. 1 and may be changed as appropriate. The recovery device 30 is electrically connected to the control device 40, and its operation is controlled by the control device 40.

[0027] The reusable product collection section 31 has a spray nozzle 31a and a collection box 31b. The defective product collection section 32 has a spray nozzle 32a and a collection box 32b. The non-defective product collection section 33 has a spray nozzle 33a and a collection box 33b. These spray nozzles 31a, 32a, and 33a basically have the same structure, and the collection boxes 31b, 32b, and 33b also basically have the same structure. For this reason, only the spray nozzle 31a and the collection box 31b will be described as representative examples.

[0028] The spray nozzle 31a and the collection box 31b are provided at positions facing each other across a conveying path in which the suction holes (corresponding to the suction holes 21g) of the conveyor belt 51a are aligned. The spray nozzle 31a is disposed in the suction chamber 51f and, for example, sprays gas (e.g., air) toward the conveyor belt 51a, causing the tablets T to fall from the conveyor belt 51a. At this time, the gas sprayed from the spray nozzle 31a passes through the suction holes of the conveyor belt 51a and hits the tablets T. The spray nozzle 31a is electrically connected to the control device 40, and its drive is controlled by the control device 40. The collection box 31b is provided directly below the spray nozzle 31a and below the conveyor unit 51. This collection box 31b receives and stores the tablets T that have fallen from the conveyor belt 51a due to the gas sprayed from the spray nozzle 31a.

[0029] Here, the tablets T that have passed through the reusable product recovery section 31 and the defective product recovery section 32 are transported along with the movement of the conveyor belt 51a, and reach a position near the end of the conveyor belt 51a on the side of each driven pulley 51c. At this position, the suction action no longer acts on the tablets T, but gas is sprayed onto the tablets T from above by the spray nozzle 33a, causing the tablets T to fall from the conveyor belt 51a. Therefore, by providing the spray nozzle 33a, it is possible to reliably cause the tablets T to fall from the conveyor belt 51a. The collection box 33b receives and stores the tablets T that have fallen from the conveyor belt 51a due to the gas sprayed from the spray nozzle 33a.

[0030] The control device 40 controls each part of the tablet printing apparatus 1, such as the supply device 10, first printing device 20, second printing device 50, and recovery device 30, based on various information and various programs. The control device 40 also receives detection data (e.g., detection signals) transmitted from the position detector 21e and detection unit 22 of the conveying unit 21, and the position detector 51e and detection unit 52 of the conveying unit 51, and also receives image data transmitted from the first imaging unit 23, second imaging unit 25, first imaging unit 53, and second imaging unit 55. The control device 40 is realized, for example, by an electronic circuit such as an integrated circuit or a computer.

[0031] (Configuration example of the movement mechanism of the tablet printing device) Next, a configuration example of the movement mechanisms (first movement mechanism 13A, second movement mechanism 24A, third movement mechanism 51A, and fourth movement mechanism 54A) of the tablet printing apparatus 1 will be described with reference to FIG.

[0032] 3, the tablet printing apparatus 1 according to this embodiment includes a first moving mechanism 13A, a second moving mechanism 24A, a third moving mechanism 51A, and a fourth moving mechanism 54A. These moving mechanisms 13A, 24A, 51A, and 54A are electrically connected to the control device 40, and their driving is controlled by the control device 40.

[0033] The first movement mechanism 13A is a mechanism that moves the delivery feeder 13 in the height direction. The second movement mechanism 24A is a mechanism that moves the inkjet head 24 in the height direction. The third movement mechanism 51A is a mechanism that moves the conveying unit 51 in the height direction. The fourth movement mechanism 54A is a mechanism that moves the inkjet head 54 in the height direction. The height direction is the lifting direction, which is the Z-axis direction in the example of Figure 3.

[0034] Each of the movement mechanisms 13A, 24A, 51A, and 54A may be, for example, a movement mechanism that uses a motor as a drive source and a ball screw or linear guide as a guide, but other movement mechanisms may also be used. Furthermore, each of the movement mechanisms 13A, 24A, 51A, and 54A may have the same configuration or different configurations.

[0035] The conveying unit 21 is fixed (no moving mechanism is provided) and does not move in the height direction in this embodiment. In the example of FIG. 3, the reference height position Ba and the reference height position Bc are, for example, the initial height position of the conveying unit 21 and are fixed values. The reference height position Bb is, for example, the initial height position of the conveying unit 51 and is also a fixed value. These reference height positions Ba, Bc, and Bb are, for example, determined in advance and stored in the memory unit 42. More specifically, the reference height position Ba is the height position of the upper conveying surface of the conveying belt 21a initially set in the conveying unit 21, the reference height position Bc is the height position of the lower conveying surface of the conveying belt 21a initially set in the conveying unit 21, and the reference height position Bb is the height position of the upper conveying surface of the conveying belt 51a initially set in the conveying unit 51. The reference height position Ba (and the reference height position Bc) function as a first reference height position. The reference height position Bb functions as a second reference height position.

[0036] The alignment feeder 12 is fixed in the same manner as the conveying unit 21 (no moving mechanism is provided), and does not move in the height direction in this embodiment. The height position of the alignment feeder 12 is fixed in a state where it is adjusted so that the height position of the conveying surface of the alignment feeder 12 is the same as the height position of the conveying surface of the conveying unit 21 (adjusted to match the reference height position Ba). Reference height positions are also set for the delivery feeder 13 and the inkjet head 24 and inkjet head 54.

[0037] The heightwise separation distance B1 between the delivery feeder 13 and the conveying unit 21 is adjusted by moving the delivery feeder 13 in the height direction using the first movement mechanism 13A. The heightwise separation distance B2 between the conveying unit 21 and the inkjet head 24 is adjusted by moving the inkjet head 24 in the height direction using the second movement mechanism 24A. The heightwise separation distance B3 between the conveying unit 21 and the conveying unit 51 is adjusted by moving the conveying unit 51 in the height direction using the third movement mechanism 51A. The heightwise separation distance B4 between the conveying unit 51 and the inkjet head 54 is adjusted by moving the inkjet head 54 in the height direction using the fourth movement mechanism 54A. For example, if the fourth movement mechanism 54A is integral with the conveying unit 51, the fourth movement mechanism 54A will move together with the movement of the conveying unit 51. In this embodiment, the inkjet head 54 and the fourth movement mechanism 54A will be described as being integral with the conveying unit 51.

[0038] Specifically, the separation distance B1 is the separation distance in the height direction between the lower conveying surface of the delivery feeder 13 and the upper conveying surface of the conveying unit 21. This separation distance B1 is adjusted, for example, so that the tablets T can be smoothly delivered between the delivery feeder 13 and the conveying unit 21. The separation distance B2 is the separation distance in the height direction between the upper conveying surface of the conveying unit 21 and the ejection surface of the inkjet head 24. This separation distance B2 is adjusted so that the ink ejected from the inkjet head 24 can smoothly land on the tablets T on the conveying unit 21 and so that the tablets T on the conveying unit 21 do not collide with the inkjet head 24. Note that in order to suppress the influence of air currents and so that the ink ejected from the inkjet head 24 can smoothly land on the tablets T on the conveying unit 21, it is desirable to bring the ejection surface of the inkjet head 24 closer to the upper surfaces of the tablets T on the conveying unit 21, i.e., to shorten the separation distance B2.

[0039] The separation distance B3 is the separation distance in the height direction between the lower conveying surface of the conveying unit 21 and the upper conveying surface of the conveying unit 51. This separation distance B3 is adjusted, for example, so that the tablets T can be smoothly transferred between the conveying unit 21 and the conveying unit 51. The separation distance B4 is the separation distance in the height direction between the upper conveying surface of the conveying unit 51 and the ejection surface of the inkjet head 54. This separation distance B4 is adjusted so that the ink ejected from the inkjet head 54 can smoothly land on the tablets T on the conveying unit 51 and so that the tablets T on the conveying unit 51 do not collide with the inkjet head 54. Note that, like the separation distance B2 described above, it is desirable to shorten the separation distance B4.

[0040] The conveying surface of the aforementioned delivery feeder 13 is a surface along which the tablets T are conveyed in the delivery feeder 13, and is the lower surface of the delivery feeder 13 (the surface of the delivery feeder 13 on the conveying unit 21 side). The conveying surface of the conveying unit 21 is a surface along which the tablets T are conveyed in the conveying unit 21 (conveyor belt 21a), and the upper conveying surface of the conveying unit 21 is the surface of the conveying unit 21 on the inkjet head 24 side, and the lower conveying surface of the conveying unit 21 is the surface of the conveying unit 21 on the conveying unit 51 side. Similarly, the conveying surface of the conveying unit 51 is a surface along which the tablets T are conveyed in the conveying unit 51 (conveyor belt 51a), and the upper conveying surface of the conveying unit 51 is the surface of the conveying unit 51 on the inkjet head 54 side. Furthermore, the ejection surface of the inkjet head 24 is a surface on which the nozzles 24a are formed in the inkjet head 24, and is the surface of the inkjet head 24 on the conveying unit 21 side. Similarly, the ejection surface of the inkjet head 54 is the surface of the inkjet head 54 on which the nozzles (corresponding to the nozzles 24a) are formed, and is the surface of the inkjet head 54 on the transport unit 51 side.

[0041] In the example of FIG. 3 , the conveying unit 21 is fixed, but may be configured to be movable by a moving mechanism, similar to the conveying unit 51. The alignment feeder 12 is also fixed, but may be configured to be movable by a moving mechanism, similar to the delivery feeder 13. However, it is preferable that any of the alignment feeder 12, the delivery feeder 13, the conveying unit 21, and the conveying unit 51 be fixed. When the conveying unit 21 and the alignment feeder 12, which are located at the center in the Z direction, are fixed as in this embodiment, the height position can be adjusted by simply moving the delivery feeder 13 and the conveying unit 51, which are located above and below them. This is preferable because fewer components need to be moved compared to when only the delivery feeder 13 or only the conveying unit 51 is fixed. Furthermore, for example, to simplify the moving mechanism and reduce the size, it is preferable that the conveying unit 21 including the suction chamber 21f, to which a pump is connected via a suction pipe, or the conveying unit 51 including the suction chamber 51f, be fixed, compared to when the alignment feeder 12 or the delivery feeder 13 is fixed. That is, it is desirable to fix either the transport unit 21 or the transport unit 51, and it is particularly desirable to fix the transport unit 21 located in the center in the Z direction.

[0042] 3, inkjet head 24 is configured to be movable in the height direction by second moving mechanism 24A, but for example, if detection unit 22, first imaging unit 23, inkjet head 24, and second imaging unit 25 (see FIG. 1) are built into a housing or the like, the housing may be configured to be movable in the height direction by second moving mechanism 24A. Such a configuration is also applicable to inkjet head 54.

[0043] (Example of control device configuration) Next, an example of the configuration of the control device 40 will be described with reference to FIG.

[0044] 4, the control device 40 includes an image processing unit 41, a storage unit 42, and a control unit 43. An input device 40a and an output device 40b are connected to the control device 40. The input device 40a is realized by, for example, a switch, a touch panel, a keyboard, a mouse, etc. The output device 40b is realized by, for example, a display, a lamp, a meter, etc.

[0045] The image processing unit 41 captures the first image captured by the first imaging unit 23 or the first imaging unit 53 and the second image captured by the second imaging unit 25 or the second imaging unit 55, and processes the images using a known image processing technique. For example, the image processing unit 41 processes the first image obtained from the first imaging unit 23 to acquire the presence or absence of damage or foreign matter adhering to the tablet T, as well as the position of the tablet T in the X direction, Y direction, and θ direction. The image processing unit 41 also processes the second image obtained from the second imaging unit 25 to acquire image information of the printing pattern printed on the tablet T. The image processing unit 41 transmits the acquired information on the presence or absence of damage or foreign matter adhering to the tablet T, the position information of each tablet T in the X direction, Y direction, and θ direction, and the image information of the printing pattern printed on each tablet T to the control unit 43.

[0046] The storage unit 42 stores various programs and various information. This storage unit 42 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk. The storage unit 42 stores production data (production information), print data related to printing, conveying speed data, and the like. Production data refers to data that changes with the production (manufacturing) of the printed tablets T. An example of the production data is a lot number. The production data may be generated based on information input by the user using the input device 40a, or may be automatically generated by the control unit 43.

[0047] The control unit 43 is a computer such as a CPU (Central Processing Unit), MCU (Micro Control Unit), or MPU (Micro Processing Unit), and controls each unit. The control unit 43 may be realized, for example, by hardware and / or software. For example, the control unit 43 controls the supply device 10, the first printing device 20, the second printing device 50, the collection device 30, the image processing unit 41, the memory unit 42, and each of the movement mechanisms 13A, 24A, 51A, and 54A based on various information and programs stored in the memory unit 42. The control unit 43 also receives detection signals transmitted from the position detector 21e and the detection unit 22 of the conveying unit 21, and the position detector 51e and the detection unit 52 of the conveying unit 51.

[0048] Here, the control unit 43 acquires the position of the tablet T in the conveying direction A1 on the conveyor belt 21a based on the detection information transmitted from the detection unit 22 in the first printing device 20, i.e., the timing at which the tablet T on the conveyor belt 21a is detected, and sets the first imaging timing of the first imaging unit 23, the print start timing of the inkjet head 24, and the second imaging timing of the second imaging unit 25 based on the position information indicating the position of the tablet T in the conveying direction A1, generates timing information indicating these timings, and stores it in the storage unit 42. The print start timing is the timing at which printing starts on the tablet T that has reached the printing position directly below the inkjet head 24. The control unit 43 can acquire information such as the movement amount (rotation amount) and speed of the conveyor belt 21a based on the detection information transmitted from the position detector 21e.

[0049] Furthermore, in the first printing device 20, the control unit 43 sets printability information indicating whether or not printing is possible for the tablets T for which the resulting data has been obtained, based on information on the presence or absence of damage or foreign matter on the tablets T transmitted from the image processing unit 41 (this information is information based on the first image). Then, the control unit 43 sets printing conditions as printing condition information for the tablets T for which printing has been set possible. At this time, the control unit 43 sets printing conditions for the tablets T for which the position information has been obtained, based on position information in the X direction, Y direction, and θ direction of the tablets T transmitted from the image processing unit 41 (this information is information based on the first image).

[0050] For example, the control unit 43 sets printing conditions for controlling the inkjet head 24 based on the printing pattern in the first printing device 20. Specifically, the control unit 43 determines the range of nozzles 24a to be used for printing the target tablet T in the inkjet head 24, i.e., the nozzle range to be used, based on the position information of the tablet T in the Y direction and the printing pattern, and sets printing conditions including the nozzle range to be used and the printing start timing. Note that if the tablet T has a directional shape, the control unit 43 sets printing conditions corresponding to the position of the tablet T in the θ direction based on the position information of the tablet T in the θ direction. As an example, the control unit 43 registers 180 printing patterns in the memory unit 42, in which the orientation of the printing pattern is rotated by 1 degree in a range from 0 degrees to 179 degrees, and selects a printing pattern with an angle that matches the position of the tablet T in the θ direction from these printing patterns to set the printing conditions.

[0051] Furthermore, the control unit 43 determines whether the print pattern has been printed in a predetermined shape and size at a predetermined position on the tablet T, i.e., whether the print pattern has been printed normally on the tablet T, based on the print position information, shape information, and size information of the print pattern printed on the tablet T transmitted from the image processing unit 41 in the first printing device 20 (this information is based on the second image), and sets print quality information for the tablet T (print status inspection). For example, in determining the shape and size of the print pattern, the control unit 43 registers a test print pattern in the memory unit 42 and compares the test print pattern with the print pattern on the tablet T after actual printing (the print pattern printed on the tablet T).

[0052] Thereafter, if the control unit 43 determines that the print pattern for inspection and the print pattern on the tablet T after actual printing match within the tolerance range, it determines that the print result of the tablet T is good (passes). On the other hand, if the control unit 43 determines that the print pattern for inspection and the print pattern on the tablet T after actual printing do not match within the tolerance range, it determines that the print result of the tablet T is bad (fails). Tablets T that are determined to have a bad print result are ejected by the defective product collection unit 32 (defective ejection device).

[0053] The various processes in the first printing device 20 as described above are similarly executed by the control unit 43 in the second printing device 50. The control unit 43 appropriately stores various information (e.g., tablet T position information, timing information, printability information, printing condition information, print quality information, etc.) in the storage unit 42. However, when the target tablet T is collected by the collection device 30, for example, after it falls from the downstream end of the conveying unit 51 in the conveying direction A2 and a predetermined time (e.g., several seconds) has elapsed, the various information is deleted from the storage unit 42. However, if such information is required in a later process, it is possible to leave the various information for each tablet T intact or to store it in a storage medium (external storage) outside the device. When storing various information for each tablet T, this information may be linked to the manufacturing date and time, lot number, etc., and stored so that if a defective tablet T is found after shipping after printing, the cause can be traced back to the original information.

[0054] (Position adjustment process) Next, the position adjustment process performed by the tablet printing apparatus 1 will be described with reference to Fig. 5. After this position adjustment process is performed, the printing process (including the inspection process) is performed. Note that various information such as data required for position adjustment, printing, and inspection is stored in advance in the storage unit 42.

[0055] The position adjustment process is executed when the user replaces either or both of the conveyor belt 21a of the conveyor unit 21 and the conveyor belt 51a of the conveyor unit 51. For example, the user replaces either or both of the conveyor belt 21a and the conveyor belt 51a, and instructs the control unit 43 to execute the position adjustment process by operating the input device 40a. Note that, since the thickness of conveyor belts typically varies from one to another, the thickness of the conveyor belt before and after replacement often differs by about ±1 mm.

[0056] Next, the content executed by the control unit 43 based on the information input via the input device 40a will be described.

[0057] 5, in step S11, the control unit 43 measures the thickness change of the conveyor belt 21a with the detection unit 22, and measures the thickness change of the conveyor belt 51a with the detection unit 52. For example, the detection unit 22 measures the thickness change of the conveyor belt 21a over one circumference by detecting the height change of the conveying surface of the conveyor belt 21a over one circumference. Similarly, the detection unit 52 measures the thickness change of the conveyor belt 51a over one circumference by detecting the height change of the conveying surface of the conveyor belt 51a over one circumference. For such measurements, the detection unit 22 detects the height of the conveying surface of the conveyor belt 21a, and the detection unit 52 detects the height of the conveying surface of the conveyor belt 51a while the conveyor belts 21a and 51a rotate for at least one circumference.

[0058] It is not necessary to detect the height change of the conveying surface of the conveying belt 21a or the conveying belt 51a over one revolution. For example, the height of the conveying surface may be detected at several locations or at one location. However, the more detection locations, the higher the measurement accuracy. Furthermore, it is sufficient to measure the thickness change by the detection unit 22 or the detection unit 52 only for the replaced belt of the conveying belt 21a or the conveying belt 51a. Furthermore, the reference height position Ba, the reference height position Bc, and the reference height position Bb are measured in advance using a similar method and stored in the memory unit 42.

[0059] The detection unit 22 is, for example, a laser sensor. The laser sensor detects the distance from the light-emitting portion to the conveying surface of the conveyor belt 21a and sequentially outputs detection values ​​(detection signals). The laser sensor functions as a sensor that detects the arrival of tablets T based on changes in the detection value, and in step S11, it functions as a sensor that detects the height of the conveying surface of the conveyor belt 21a. This also applies to the detection unit 52. In the position adjustment process, before tablets T are supplied to the hopper 11, i.e., when the hopper 11 is empty, the detection units 22 and 52 are turned on and are used to measure the height positions of the individual conveying surfaces of the conveyor belt 21a and conveyor belt 51a.

[0060] Note that a mechanism such as a shutter that prevents the tablets T from passing between the hopper 11 and the alignment feeder 12 may be provided so that the height position is measured by the detection unit 22 and the detection unit 52 in a state in which the tablets T are not supplied beyond the alignment feeder 12. In short, the height position may be measured by the detection unit 22 and the detection unit 52 in a state in which no tablets T are present in the detection target areas of the conveyor belts 21a and 51a that are detected by the detection unit 22 and the detection unit 52.

[0061] In step S12, the control unit 43 calculates the correction values ​​C1 and C2 using information about the thickness change (height change of the conveying surface over one revolution) of each of the conveyor belts 21a and 51a. The correction value C1 functions as the first correction value, and the correction value C2 functions as the first or third correction value.

[0062] The correction value C1 is a correction value for adjusting the separation distance B1 in the height direction between the delivery feeder 13 and the conveying unit 21, the separation distance B2 in the height direction between the conveying unit 21 and the inkjet head 24, the separation distance B3 in the height direction between the conveying unit 21 and the conveying unit 51, and the separation distance B4 in the height direction between the conveying unit 51 and the inkjet head 54. The correction value C2 is a correction value for adjusting the separation distance B3 in the height direction between the conveying unit 21 and the conveying unit 51, and the separation distance B4 in the height direction between the conveying unit 51 and the inkjet head 54.

[0063] For example, the control unit 43 uses information about the change in thickness of the conveyor belt 21a over one circumference (the change in height of the conveying surface over one circumference) to calculate an average value by averaging the thicknesses of the conveyor belt 21a over one circumference, and calculates the height position of the conveyor belt 21a (the height position of the conveying unit 21) based on the calculated average value. The control unit 43 then compares the height position of the conveyor belt 21a with the reference height position Ba and calculates a correction value C1 based on the difference between the height position of the conveyor belt 21a and the reference height position Ba. If the height position of the conveyor belt 21a increases relative to the reference height position Ba, the value is positive, and if the height position of the conveyor belt 21a decreases, the value is negative. If the correction value is positive, the conveyor belt 21a is moved upward from the reference height position Ba (reference height position Bb), and if the correction value is negative, the conveyor belt 21a is moved downward from the reference height position Ba (reference height position Bb). The difference between the actual height position of the conveyor belt 21a and the reference height position Ba may be used as the correction value C1.

[0064] Furthermore, for example, the control unit 43 uses information about the change in thickness of the conveyor belt 51a over one circumference (the change in height of the conveying surface over one circumference) to calculate an average value by averaging the thicknesses of the conveyor belt 51a over one circumference, and calculates the height position of the conveyor belt 51a (the height position of the conveying unit 51) based on the calculated average value. The control unit 43 then compares the height position of the conveyor belt 51a with the reference height position Bb and calculates a correction value C2 based on the difference between the height position of the conveyor belt 51a and the reference height position Bb. If the height position of the conveyor belt 51a increases relative to the reference height position Bb, the value is positive, and if the height position of the conveyor belt 51a decreases, the value is negative. The correction values ​​C1 and C2 are appropriately converted (according to the direction of movement) and applied based on the calculated difference (details will be described later). Note that the difference between the actual height position of the conveyor belt 51a and the reference height position Bb may be used as the correction value C2.

[0065] Furthermore, before replacing one or both of the conveyor belts 21a and 51a, for example, the height position of the conveyor unit 21, i.e., the height position of the upper conveying surface of the conveyor belt 21a, is grasped in advance as a reference height position Ba and stored in the memory unit 42, and the height position of the lower conveying surface of the conveyor belt 21a is grasped in advance as a reference height position Bc and stored in the memory unit 42. Similarly, the height position of the conveyor unit 51, i.e., the height position of the upper conveying surface of the conveyor unit 51, is grasped in advance as a reference height position Bb and stored in the memory unit 42.

[0066] In step S13, the control unit 43 stores the calculated correction values ​​C1 and C2 in the storage unit .

[0067] In step S14, the control unit 43 selects the type information of the tablets T to be printed, that is, the tablet type information, and calculates the correction value D1. The correction value D1 functions as a second correction value.

[0068] The correction value D1 is a correction value for adjusting the separation distance B1 in the height direction between the delivery feeder 13 and the conveying unit 21, the separation distance B2 in the height direction between the conveying unit 21 and the inkjet head 24, the separation distance B3 in the height direction between the conveying unit 21 and the conveying unit 51, and the separation distance B4 in the height direction between the conveying unit 51 and the inkjet head 54. This correction value D1 is a value for optimizing each of the separation distances B1 to B4 for the type of tablet T.

[0069] For example, the control unit 43 selects tablet variety information in response to an input operation by the user on the input device 40a. The tablet variety information includes, for example, any or all of tablet identification information, tablet thickness information, and tablet shape information. The tablet identification information includes, for example, one or both of the name and number of the tablet T. The tablet thickness information includes, for example, information on the thickness of the tablet T, such as several mm. The tablet shape information includes, for example, information on the shape of the tablet T, such as a disk, triangular plate, oval plate, spindle shape, or lens shape. Such tablet variety information is, for example, stored in advance in the storage unit 42.

[0070] The control unit 43 may select tablet variety information by receiving information on the tablet variety to be produced next, transmitted from an external device. Examples of the external device include a personal computer and a server, and a barcode reader. The barcode reader reads the tablet variety information from a barcode attached to a bottle containing the tablets T, for example.

[0071] Next, the control unit 43 determines a correction value D1 from a correction table T1 as shown in FIG. 6 based on the selected tablet variety information. This correction table T1 is, for example, stored in advance in the memory unit 42. In the example of FIG. 6, the correction table T1 has a correction value D1 for each tablet variety information. Tablet variety information includes a1, b1, and c1, and the correction values ​​D1 include a2, b2, c2, etc. This correction value D1 is set to optimize the conditions for each tablet T variety. Each of a1, b1, and c1 includes, for example, any one or all of tablet identification information, tablet thickness information, and tablet shape information. In other words, the correction value D1 may be set for each identification information, tablet thickness information, or tablet shape information, or may be set for information including any two or all of the tablet identification information, tablet thickness information, and tablet shape information.

[0072] The thickness of the tablet T varies depending on the type. The thickness also varies. For example, if the tablet T is a sugar-coated tablet, the thickness varies by ±0.5 mm. Since the distance from the upper surface of the tablet T on the conveyor belt 21a to the discharge surface of the inkjet head 24 is approximately 1 to 1.5 mm, if the tablet T is a type of tablet with large individual variations in thickness, the heightwise separation distance B2 between the conveyor belt 21a and the inkjet head 24 needs to be set larger than when the tablet T is a type of tablet with small individual variations in thickness. This is because, if the tablet T is a type of tablet with large individual variations in thickness, the tablet T may collide with the inkjet head 24 if the heightwise separation distance B2 between the conveyor belt 21a and the inkjet head 24 is set to the same value as when the tablet T is a type of tablet with small individual variations in thickness. Taking this into consideration, the correction value D1 is set to optimize the conditions for the type of tablet T.

[0073] In addition, differences in the types of tablets T include not only differences in thickness but also differences in shape. Tablets T come in a variety of shapes, including flat tablets called flat tablets and tablets T with a curved surface that contacts the conveyor belt 21a, such as sugar-coated tablets. For tablets T with a curve, if the height-wise separation distance B1 between the delivery feeder 13 and the conveying unit 21, or the height-wise separation distance B3 between the conveying unit 21 and the conveying unit 51, is too narrow, the curved surface of the tablet T is pinched tightly from above and below, causing the tablet T to shake, changing its posture or continuing to shake. This leads to printing defects. Taking these factors into consideration, the correction value D1 is set to optimize the conditions for each type of tablet T.

[0074] In step S15, the control unit 43 stores the calculated correction value D1 in the storage unit .

[0075] In step S16, the control unit 43 calculates appropriate height positions for the delivery feeder 13 and the inkjet head 24 based on the correction values ​​C1 and D1 stored in the memory unit 42, and calculates an appropriate height position for the conveying unit 51 based on the correction values ​​C1, C2, and D1 stored in the memory unit 42. In this embodiment, since the movement mechanism 54A is fixed to the conveying unit 51, the correction value C1 is not used in adjusting the height position of the inkjet head 54.

[0076] For example, if the difference between the height position of the conveying unit 21 and the reference height position Ba is +1.0 mm and the correction value D1 is +0.5 mm, the correction value C1 becomes +1.0 mm, and the appropriate height positions of the delivery feeder 13 and the inkjet head 24 are their initial positions +1.5 mm (=1.0 + 0.5 mm). Therefore, in this case, the movement mechanism 13A of the delivery feeder 13 and the movement mechanism 24A of the inkjet head 24 move the delivery feeder 13 and the inkjet head 24 to positions +1.5 mm from their initial positions (positions elevated 1.5 mm from the initial positions) stored in advance in the storage unit 42.

[0077] The correction value C1 applied to the conveying unit 51 at this time will be described. Since the difference in conveying unit 21 is +1.0 mm, the average thickness change of the conveying belt 21a is +1.0 mm. This means that the height position of the conveying unit 51 side of the conveying belt 21a of the conveying unit 21 (the conveying surface below the conveying belt 21a) is located at the reference height position Bc-1.0 mm. In other words, the correction value C1 applied to the conveying unit 51 is -1.0 mm. In addition to this, a correction value D1 is applied. The correction value D1 of +0.5 mm indicates that each of the separation distances B1 to B4 is increased by an additional 0.5 mm from the predetermined interval. Therefore, in order to increase the separation distance B3 between the conveying unit 21 and the conveying unit 51 by an additional 0.5 mm, the conveying unit 51 needs to be lowered, and therefore the sign of the correction value D1 is made negative, i.e., -0.5 mm. Therefore, the movement mechanism 51A moves the position of the transport unit 51 to a position −1.5 mm from the reference height position Bb.

[0078] In addition, for example, when the difference of conveying unit 21 is +1.0 mm and the difference of conveying unit 51 is +1.5 mm, and the correction value D1 is +0.5 mm, the calculation method of correction value C2 and correction value D1 (i.e., the amount by which conveying unit 51 is moved) is illustrated.

[0079] The difference in the conveying unit 51 is +1.5 mm. This indicates that the average thickness change of the conveying belt 51a is +1.5 mm. To accommodate the 1.5 mm rise in the upper conveying surface of the conveying belt 51a, the sign of the correction value C2 is made negative, and the correction value C2 is set to -1.5 mm. In addition, the correction value D1 is applied. The correction value D1 of +0.5 mm indicates that the separation distances B1 to B4 are increased by an additional 0.5 mm. Therefore, in order to increase the separation distance B3 between the conveying unit 21 and the conveying unit 51 by an additional 0.5 mm, the conveying unit 51 must be lowered, and therefore the sign of the correction value D1 is made negative, resulting in -0.5 mm. Therefore, the appropriate height position of the conveying unit 51 is the reference height position Bb - 3 mm (= -1.0 - 1.5 - 0.5 mm). As mentioned above, the inkjet head 54 is integral with the conveying unit 51. Therefore, only correction values ​​C2 and D1 are applied, without consideration of correction value C1. That is, since the difference in conveyance section 51 is +1.5 mm, it is necessary to raise inkjet head 54 to ensure separation distance B4, so correction value C2 is +1.5 mm. In addition, correction value D1 of +0.5 mm is applied, so the appropriate height position of inkjet head 54 is the initial position (e.g., previous position) +2 mm (= 1.5 mm + 0.5 mm).

[0080] Note that if the conveyor belt 21a has not been replaced, the correction value C1 is set to 0. Also, if the conveyor belt 51a has not been replaced, the correction value C2 is set to 0. More specifically, if the conveyor belt 21a has been replaced, the height position of the conveyor unit 21 is normally misaligned with the reference height position Ba, so the correction value C1 is set. However, if the conveyor belt 21a has not been replaced, the height position of the conveyor unit 21 is normally misaligned with the reference height position Ba, so the correction value C1 is set to 0. Similarly, if the conveyor belt 51a has been replaced, the height position of the conveyor unit 51 is normally misaligned with the reference height position Bb, so the correction value C2 is set. However, if the conveyor belt 51a has not been replaced, the height position of the conveyor unit 51 is not misaligned with the reference height position Ba, so the correction value C2 is set to 0. Note that the correction value D1 is also applied when the conveyor belts 21a and 51a are not replaced.

[0081] In step S17, the control unit 43 determines the individual movement amounts to reach the calculated appropriate height positions, and moves the delivery feeder 13, the inkjet heads 24, 54, and the transport unit 51 by the calculated movement amounts.

[0082] According to this position adjustment process, the heightwise separation distance B1 between the delivery feeder 13 and the conveying unit 21, the heightwise separation distance B2 between the conveying unit 21 and the inkjet head 24, the heightwise separation distance B3 between the conveying unit 21 and the conveying unit 51, and the heightwise separation distance B4 between the conveying unit 51 and the inkjet head 54 are appropriately adjusted. Therefore, it is possible to prevent the ink ejected from the inkjet head 24 (or the inkjet head 54) from improperly landing on the tablet T on the conveying belt 21a (or the conveying belt 51a) or the tablet T on the conveying belt 21a (or the conveying belt 51a) from colliding with the inkjet head 24 (or the inkjet head 54). It is also possible to prevent the tablet T from falling due to improper transfer of the tablet T between the respective conveying mechanisms such as the delivery feeder 13, the conveying unit 21, and the conveying unit 51, or the tablet from shifting in position due to the transfer of the tablet T. As a result, printing defects can be reduced.

[0083] Note that adjusting the height-wise separation distance B1 between the delivery feeder 13 and the conveying section 21 may result in an inappropriate separation distance between the aligning feeder 12 and the delivery feeder 13. For example, if the height position of the delivery feeder 13 is raised to ensure separation distance B1, the separation distance between the aligning feeder 12 and the delivery feeder 13 may become too large compared to the appropriate separation distance because the height position of the alignment feeder 12 is fixed. In such a case, it is possible to raise only the height position of the end of the delivery feeder 13 on the conveying section 21 side while maintaining the appropriate separation distance from the alignment feeder 12. In other words, the delivery feeder 13 is provided at an incline. Conversely, if the separation distance between the aligning feeder 12 and the delivery feeder 13 becomes too small, the delivery feeder 13 may be provided at an incline so that the end of the delivery feeder 13 on the aligning feeder 12 side is higher than the end on the conveying section 21 side.

[0084] (Printing process) Once the position adjustment process is completed, a large number of tablets T are supplied to the hopper 11, and the printing process begins. In the printing process, 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 supplied sequentially from the hopper 11 to the alignment feeder 12, which then arranges them in a line and moves them. The tablets T moving in this line are then supplied sequentially 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 by the rotation of the drive pulley 21b and each driven pulley 21c by the motor 21d. The tablets T supplied onto the conveyor belt 21a at random intervals are lined up in a line on the conveyor belt 21a and transported at a predetermined conveying speed.

[0085] The tablet T on the conveyor belt 21a is detected by the detection unit 22. More specifically, when the tablet T on the conveyor belt 21a reaches a detection position (for example, a laser light irradiation position) directly below the detection unit 22, it is detected by the detection unit 22, and based on the timing at which the tablet T is detected, the position of the tablet T in the conveying direction A1 on the conveyor belt 21a is recognized by the control unit 43. Then, position information indicating the position of the tablet T in the conveying direction A1 is generated by the control unit 43 and stored in the memory unit 42.

[0086] Next, the tablet T on the conveyor belt 21a is imaged by the first imaging unit 23. Specifically, the tablet T on the conveyor belt 21a is imaged by the first imaging unit 23 at the first imaging timing when the tablet T on the conveyor belt 21a reaches the imaging position directly below the first imaging unit 23, and the first image obtained by imaging by the first imaging unit 23 is transmitted to the control device 40. This first image is processed by the image processing unit 41 of the control device 40. Specifically, the first image is processed by the image processing unit 41, and based on the first image, information on the presence or absence of damage to the tablet T or adhesion of foreign matter, as well as position information of the tablet T in the X direction, Y direction, and θ direction are generated and stored in the memory unit 42.

[0087] The control unit 43 determines whether printing on the target tablet T is possible based on information on the presence or absence of damage to the tablet T or foreign matter attached thereto. If it is determined that printing on the target tablet T is possible, printing is performed by the inkjet head 24. Note that, based on information such as the position information of the tablet T in the X direction, Y direction, and θ direction, and the printing pattern, printing conditions including the nozzle range to be used and the printing start timing for the tablet T set as printable (printable tablet T) are set in the memory unit 42. Based on the above-mentioned print start timing (the timing at which printing on the tablet T is started), the ejection timing for the tablet T (the timing at which ink is ejected onto the tablet T) is determined. On the other hand, if it is determined that printing on the target tablet T is not possible, operations related to printing and inspection on the target tablet T are restricted. Note that the printability information for the tablet T is appropriately stored in the memory unit 42. Note that "restriction" of operations related to printing and inspection means that at least processing related to printing and inspection on the target tablet T is not performed.

[0088] When printing is performed by the inkjet head 24 based on the above printing conditions, the control unit 43 controls the inkjet head 24 to print a predetermined print pattern on the printable tablets T on the conveyor belt 21a. In detail, the printable tablets T on the conveyor belt 21a that have passed below the first imaging unit 23 are printed by the inkjet head 24 based on the above printing conditions at the printing start timing when they reach the printing position directly below the inkjet head 24. In the inkjet head 24, ink is appropriately ejected from each nozzle 24a, and the print pattern is printed on the printing surface, which is the upper surface of the tablet T.

[0089] Next, the printed tablet T on the conveyor belt 21a is imaged by the second imaging unit 25. More specifically, the printed tablet T on the conveyor belt 21a is imaged by the second imaging unit 25 at the second imaging timing when the tablet T reaches the imaging position directly below the second imaging unit 25, and the second image obtained by imaging by the second imaging unit 25 is transmitted to the control device 40. This second image is processed by the image processing unit 41 of the control device 40. More specifically, the second image is processed by the image processing unit 41, and inspection information indicating the printing position, shape, and size of the printed pattern printed on the tablet T is generated and stored in the memory unit 42.

[0090] Next, a print status inspection is performed by the control unit 43 based on the above inspection information. Specifically, based on the inspection information related to the printing position, shape, and size stored in the memory unit 42, the control unit 43 determines whether the printing pattern has been printed correctly on the tablet T, and print pass / fail information indicating whether the printing on the tablet T is pass / fail is generated and stored in the memory unit 42. For example, in the print status inspection, the printing pattern used for printing is stored in the memory unit 42 as a test printing pattern, and pass / fail information related to the predetermined printing position, shape, and size of the test printing pattern is compared with inspection information related to the printing position, shape, and size of the actually printed printing pattern stored in the memory unit 42, and it is determined whether the printing pattern has been printed correctly on the tablet T (pass or fail).

[0091] The above-mentioned printing and inspection are also repeated in the second printing device 50. The tablets T printed in the first printing device 20 are inverted and transferred to the second printing device 50 below, where the above-mentioned printing and inspection are carried out. This achieves double-sided printing on the tablets T. The conveyor belt 51a rotates in the conveying direction A2 by the rotation of the drive pulley 51b and each driven pulley 51c by the motor 51d. Therefore, the tablets T transferred onto the conveyor belt 51a are lined up in a row on the conveyor belt 51a and conveyed at a predetermined conveying speed.

[0092] Thereafter, the tablets T on the conveyor belt 51a of the second printing device 50 are collected by the collection device 30. Specifically, when the reused tablets T reach the reused product collection section 31 as the conveyor belt 51a moves, gas is blown onto the tablets T from above by the injection nozzle 31a, and the tablets T fall from the conveyor belt 51a and are collected in the collection box 31b. Similarly, when the defective tablets T reach the defective product collection section 32 as the conveyor belt 21a moves, gas is blown onto the tablets T from above by the injection nozzle 32a, and the tablets T fall from the conveyor belt 51a and are collected in the collection box 32b. Furthermore, when the non-defective tablets T reach a position near the end of the conveyor belt 51a on the side of each driven pulley 51c, the suction action on the tablets T ceases to act, and gas is blown onto the tablets T from above by the injection nozzle 33a, and the tablets T fall from the conveyor belt 51a and are collected in the collection box 33b. The control regarding the blowing of such gas is executed by the control unit 43 based on various information such as, for example, position information of the tablets T, printability information, and print quality information (print state inspection result information).

[0093] Finally, the control unit 43 determines whether printing has finished. For example, the number of printed tablets T is counted, and when that number reaches a predetermined production number, it is determined that printing has finished, and the process ends. On the other hand, if it is determined that printing has not finished, the above-mentioned printing and inspection are repeated. Regarding the determination of printing completion, it may be determined that printing has finished in response to a user's input operation on the input device 40a, for example, when the user presses a print completion button.

[0094] As described above, according to this embodiment, the tablet printing apparatus 1 comprises a conveying device (e.g., a delivery feeder 13, a conveying unit 21, or a conveying unit 51) that conveys tablets, a first inkjet head (e.g., an inkjet head 24 or an inkjet head 54) that prints on the tablets, a moving mechanism (e.g., a first moving mechanism 13A, a second moving mechanism 24A, a third moving mechanism 51A, a fourth moving mechanism 54A) that moves the conveying device or the first inkjet head in the vertical direction, and a control device 40 that controls the moving mechanism, and the control device 40 generates a first correction value (e.g., a correction value C1 or a correction value C2) based on the difference between the height position of the conveying device and a first reference height position (e.g., a reference height position Ba or a reference height position Bb), generates a second correction value (e.g., a correction value D1) based on tablet variety information regarding the tablet variety, and controls the moving mechanism based on the first correction value and the second correction value.

[0095] This allows the distance between the conveying device and the first inkjet head (for example, the heightwise distance B2 between the conveying unit 21 and the inkjet head 24, or the heightwise distance B4 between the conveying unit 51 and the inkjet head 54) to be appropriately adjusted, making it possible to prevent, for example, ink ejected from the first inkjet head from failing to land properly on the tablets T on the conveying device, or tablets T on the conveying device from colliding with the first inkjet head. Therefore, printing defects can be reduced.

[0096] Furthermore, since the separation distance between the conveying device and other conveying devices (for example, the separation distance B1 in the height direction between the delivery feeder 13 and the conveying section 21, or the separation distance B3 in the height direction between the conveying section 21 and the conveying section 51) is appropriately adjusted, it is possible to prevent, for example, the tablets T from falling due to poor transfer of the tablets T between each conveying mechanism such as the delivery feeder 13, the conveying section 21, and the conveying section 51, or the tablets from becoming misaligned due to the transfer of the tablets T. Therefore, printing defects can be reduced.

[0097] The situation in which the separation distance between the aforementioned conveying device and another conveying device, i.e., the separation distance B3 in the height direction between the conveying unit 21 and the conveying unit 51, is appropriately adjusted based on the correction values ​​C2 and D1 is when the height position of the conveying unit 21 does not change and the height position of the conveying unit 51 changes, i.e., when the conveying belt 21a is not replaced but the conveying belt 51a is replaced (correction value C1=0).When both the conveying belts 21a and 51a are replaced, in addition to the correction values ​​C2 and D1, a correction value C1 corresponding to the replacement of the conveying belt 21a is also required.

[0098] <Other embodiments> In the above description, printing is performed on tablets T using the tablet printing apparatus 1 (tablet printing method) according to the embodiment, but this can also be rephrased as printing on tablets T using the tablet printing apparatus 1 (tablet printing method) according to the embodiment to manufacture 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.

[0099] In the above description, the detection unit 22 is configured to irradiate light onto a position on the line where the suction holes 21g of the conveyor belt 21a are aligned, as shown in FIG. 2. However, for example, as shown in FIG. 7, the detection unit 22 may be configured to irradiate light onto a position shifted a predetermined distance in the Y-axis direction from that line. That is, the detection unit 22 may be configured to be shifted a predetermined distance (e.g., several mm) from the line where the suction holes 21g are aligned in a plan view. This makes it possible for the detection unit 22 to suppress the influence of light scattering by the suction holes 21g compared to when irradiating light onto a position on the line where the suction holes 21g are aligned, and therefore, for example, to accurately detect the height of one circumference of the conveyor belt 21a. However, the predetermined distance is set so that the detection unit 22 can accurately detect the arrival of the tablet T. The configuration as shown in the example of FIG. 7 can also be applied to the detection unit 52.

[0100] 8, a detection unit 22A may be newly provided in addition to the detection unit 22. This detection unit 22A detects, for example, the height of one circumference of the conveyor belt 21a. In this case, the detection unit 22 is used only to detect the arrival of tablets T. The detection unit 22A may have the same configuration as the detection unit 22, or may have a different configuration from the detection unit 22. In the example of FIG. 8, as in the example of FIG. 7, it is possible to suppress the influence of light scattering by each suction hole 21g compared to when light is irradiated to positions on a line where each suction hole 21g is aligned, so that, for example, the height of one circumference of the conveyor belt 21a can be detected with high accuracy. The configuration as in the example of FIG. 8 can also be applied to the detection unit 52.

[0101] 9, the detection unit 22 may be configured to be moved in a planar direction, for example, in the Y-axis direction, by a moving mechanism 22B. The moving mechanism 22B is a mechanism that moves the detection unit 22 in, for example, the Y-axis direction. This moving mechanism 22B is electrically connected to the control device 40, and its drive is controlled by the control device 40. For example, in the position adjustment step, the control device 40 moves the detection unit 22 from a position (initial position) where light is irradiated onto a position on a line where the suction holes 21g are aligned to a position (detection position) where light is irradiated onto a position shifted a predetermined distance from the line in the Y-axis direction. After the position adjustment step, the control device 40 moves the detection unit 22 from the detection position to the initial position. The detection position is preferably a position where the light irradiated from the detection unit 22 hits within a conveying range on the conveying surface of the conveyor belt 21a through which the tablet T is actually conveyed. 7 and 8, the example in Fig. 9 also makes it possible to suppress the effects of light scattering by each suction hole 21g compared to when light is irradiated onto positions on a line where each suction hole 21g is aligned, and therefore, for example, it is possible to accurately detect the height of one circumference of the conveyor belt 21a. The configuration in the example in Fig. 9 can also be applied to the detection unit 52.

[0102] Furthermore, in the above description, an example was given in which the tablets T were transported in a single row, but this is not limited thereto, and the number of rows may be two or more, and is not particularly limited thereto, and the number of conveyor belts 21a may be two or more, and is not particularly limited thereto. Such a configuration is also applicable to the conveyor belt 51a. Furthermore, the number of inkjet heads 24 may be two or more, and is not particularly limited thereto. Such a configuration is also applicable to the inkjet head 54.

[0103] In the above description, an inkjet head in which the nozzles 24a are arranged in a single row has been exemplified as the inkjet head 24, but this is not limiting and, for example, an inkjet head in which the nozzles 24a are arranged in multiple rows may also be used. Furthermore, a plurality of inkjet heads 24 may also be arranged in a direction perpendicular to the transport direction A1 in a horizontal plane. Such a configuration may also be applied to the inkjet head 54.

[0104] In the above description, the inkjet head 24 is configured so that the nozzles 24a are aligned in a direction perpendicular to the transport direction A1 in a horizontal plane, but this is not limiting, and the nozzles 24a may be aligned in a direction that diagonally intersects the transport direction A1 in a horizontal plane. Such a configuration can also be applied to the inkjet head 54.

[0105] In addition, in the above description, the inkjet head 54 and the fourth moving mechanism 54A are provided integrally with the transport unit 51, but this is not limiting, and for example, the inkjet head 54 may be provided alone with the moving mechanism 54A separate from the transport unit 51. In this case, the correction value C1 is used when calculating the height position of the inkjet head 54 in step S16 described above.

[0106] Furthermore, in the above description, the tablets T are supplied randomly, not at regular intervals, onto the conveyor belt 21a, but this is not limited to this and they may be supplied at regular intervals. Furthermore, in the above description, the tablets T are suction-held by the suction holes 21g formed on the conveyor belt 21a, but this is not limited to this and the tablets may be accommodated and held in pockets or the like and transported, or may be held and transported on the conveyor belt 21a by their own weight. These configurations are also applicable to the conveyor belt 51a.

[0107] Here, the aforementioned tablets T can include tablets used for medicine, food and beverages, cleaning, industrial purposes, or fragrances. 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.

[0108] 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, modifications, and combinations 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]

[0109] 1. Tablet printing equipment 10 Feeding device 11 Hopper 12 Alignment Feeder 13 Delivery Feeder 13A First moving mechanism 20 First printing device 21 Conveyor 21a Conveyor belt 21b Drive pulley 21c Driven pulley 21d Motor 21e Position detector 21f Suction Chamber 21g suction hole 22 Detection unit 22A Detector 22B Moving mechanism 23 First imaging unit 24 Inkjet head 24A Second moving mechanism 24a nozzle 25 Second imaging unit 27 Drying section 30 Recovery Device 31 Recyclable Goods Collection Department 31a Injection nozzle 31b Collection Box 32 Defective Product Collection Department 32a Injection nozzle 32b Collection Box 33 Good Product Collection Department 33b Collection Box 33a Injection nozzle 40 Control device 40a Input device 40b Output device 41 Image processing section 42 Storage section 43 Control Unit 50 Second printing device 51 Conveyor 51A Third moving mechanism 51a Conveyor belt 51b Drive pulley 51c Driven pulley 51d motor 51e Position detector 51f Suction chamber 52 Detection unit 53 First imaging unit 54 Inkjet head 54A Fourth moving mechanism 55 Second imaging unit 57 Drying section A1 Conveying direction A2 Conveying direction Ba Reference height position Bb Reference height position Bc Reference height position B1 Separation distance B2 Separation distance B3 Separation distance B4 Separation distance T tablets

Claims

1. A conveying device for conveying tablets; a first inkjet head that prints on the tablet transported by the transport device; a moving mechanism configured to move at least one of the transport device and the first inkjet head in a height direction; A control device for controlling the moving mechanism; Equipped with The control device includes: generating a first correction value based on a difference between a height position of the transport device and a first reference height position; generating a second correction value based on tablet variety information relating to the tablet variety; controlling the moving mechanism based on the first correction value and the second correction value; Tablet printing equipment.

2. The conveying device is a first conveying unit that conveys the tablet printed by the first inkjet head; a supply conveying section that delivers the tablet to the first conveying section; having the control device generates the first correction value based on a difference between a height position of the first transport unit and the first reference height position; The tablet printing device according to claim 1 , wherein the movement mechanism moves the first inkjet head and the supply and conveying unit in a height direction.

3. the first inkjet head prints on one side of the tablet; Further, a second inkjet head is provided for printing on the other side of the tablet printed by the first inkjet head, The conveying device is a first conveying unit that conveys the tablet printed by the first inkjet head; a second conveying unit that conveys the tablet printed by the second inkjet head; a supply conveying section that delivers the tablet to the first conveying section; having the moving mechanism further moves at least one of the transport device and the second inkjet head in a height direction, The control device includes: generating a third correction value based on a difference between a height position of the second transport unit and a second reference height position; adjusting a relative height position between the supply transport unit and the first transport unit and a relative height position between the first inkjet head and the first transport unit by the movement mechanism based on the first correction value and the second correction value; 2. The tablet printing device according to claim 1, wherein the relative height positions of the first conveying unit and the second conveying unit and the relative height positions of the second inkjet head and the second conveying unit are adjusted by the moving mechanism based on the first correction value, the second correction value, and the third correction value.

4. A detection unit for detecting the arrival of the tablet is further provided, The control device measures a height position of the conveying device based on a detection result of the detection unit. The tablet printing apparatus according to any one of claims 1 to 3.

5. The tablet variety information includes any one or all of the tablet identification information, the tablet thickness information, and the tablet shape information. The tablet printing apparatus according to any one of claims 1 to 3.

6. The control device, generating a first correction value based on a difference between a height position of a conveying device that conveys the tablet and a first reference height position; generating a second correction value based on tablet variety information relating to the tablet variety; Controlling a movement mechanism that moves at least one of a first inkjet head that prints on the tablet and the conveying device in a height direction based on the first correction value and the second correction value; Including, Tablet printing method.

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