Tablet printing apparatus 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

[0004] , , , , , , , , , , ,

[0005]

[0001] Embodiments of the present invention relate to a tablet printing apparatus and a tablet printing method.

Background Art

[0002] There is a tablet printing apparatus that performs printing on tablets using an inkjet head. In this tablet printing apparatus, a conveyance mechanism has been developed in which a conveyance belt is looped around a plurality of pulleys, and tablets are placed on and conveyed by this conveyance belt. Usually, suction holes are provided in the conveyance belt, and the tablets are sucked and held through the suction holes by the suction force of a suction chamber provided inside the conveyance belt.

[0003] The conveyance belt needs to be replaced when wear due to aging occurs. When the conveyance belt is replaced, the distance from the conveyance belt to the inkjet head may change slightly due to individual differences in the conveyance belt (the former), and when tablets are conveyed so as to transfer between a plurality of conveyance mechanisms, the distance between the conveyance belts before and after the transfer may change (the latter).

[0004] In the former case, printing defects may occur because the ink ejected from the inkjet head does not land well on the tablets on the conveyance belt, or the tablets on the conveyance belt collide with the inkjet head. Also, in the latter case, the tablets may not be successfully transferred between the respective conveyance mechanisms and the tablets may fall, or the position of the tablets may shift due to the transfer of the tablets, so that the positional relationship between the suction holes provided in the conveyance belt and the tablets changes, and the tablets are not stably conveyed (for example, the posture of the tablets is not stable and they sway), and printing defects may occur.

Prior Art Documents

[0006] The problem that this invention aims to solve is to provide a tablet printing apparatus and a tablet printing method that can suppress printing defects. [Means for solving the problem]

[0007] An embodiment of the present invention provides a tablet printing apparatus comprising: a conveying device for conveying tablets; a first inkjet head for printing on the tablets conveyed by the conveying device; a moving mechanism for moving at least one of the conveying device and the first inkjet head in the height direction; and a control device for controlling the moving mechanism. The transport device comprises a first transport unit for transporting the tablets printed by the first inkjet head, and a supply transport unit for delivering the tablets to the first transport unit, and the moving mechanism moves the first inkjet head and the supply transport unit in the height direction. The control device is The first transport unit A first correction value is generated based on the difference between the height position and a first reference height position, a second correction value is generated based on tablet variety information relating to the type of tablet, and the moving mechanism is controlled based on the first correction value and the second correction value. Furthermore, an embodiment of the present invention provides a tablet printing apparatus comprising: a transport device for transporting tablets; a first inkjet head for printing on the tablets transported by the transport device; a moving mechanism for moving at least one of the transport device and the first inkjet head in the height direction; and a control device for controlling the moving mechanism, wherein the first inkjet head further comprises a second inkjet head for printing on one side of the tablet and printing on the other side of the tablet printed by the first inkjet head; the transport device comprises a first transport section for transporting the tablets printed by the first inkjet head, a second transport section for transporting the tablets printed by the second inkjet head, and a supply transport section for passing the tablets to the first transport section; and the moving mechanism further comprises the transport device and the second inkjet head The mechanism moves at least one of the inkjet heads in the height direction, and the control device generates a first correction value based on the difference between the height position of the first transport unit and a first reference height position, generates a second correction value based on tablet variety information relating to the type of tablet, generates a third correction value based on the difference between the height position of the second transport unit and a second reference height position, and the moving mechanism adjusts the relative height position between the supply transport unit and the first transport unit and the relative height position between the first inkjet head and the first transport unit based on the first correction value and the second correction value, and the moving mechanism adjusts the relative height position between the first transport unit and the second transport unit and the relative height position between the second inkjet head and the second transport unit based on the first correction value, the second correction value and the third correction value.

[0008] In an embodiment of the present invention, the tablet printing method involves a control device that transports tablets. First transport unit A first correction value is generated based on the difference between the height position and the first reference height position; a second correction value is generated based on tablet variety information relating to the type of tablet; and based on the first correction value and the second correction value, The first transport unit is transported The aforementioned tablets one side The first inkjet head that performs printing and the A supply and transport unit that delivers the tablets to the first transport unit. This includes controlling a movement mechanism that moves in the vertical direction. Furthermore, the tablet printing method according to the embodiment of the present invention includes a control device that generates a first correction value based on the difference between the height position of a first transport unit that transports tablets passed from a supply transport unit and a first reference height position, generates a second correction value based on tablet variety information relating to the type of tablet, generates a third correction value based on the difference between the height position of a second transport unit that transports tablets passed from the first transport unit and a second reference height position, a transport device including the supply transport unit, the first transport unit and the second transport unit, a first inkjet head that prints on one side of the tablet transported to the first transport unit and the second transport unit that transports the tablet The invention includes moving at least one of an inkjet head, including a second inkjet head for printing on the other side of a tablet, in the height direction by a moving mechanism, and the movement by the moving mechanism includes adjusting the relative height position of the supply transport unit and the first transport unit and the relative height position of the first inkjet head and the first transport unit based on the first correction value and the second correction value, and adjusting the relative height position of the first transport unit and the second transport unit and the relative height position of the second inkjet head and the second transport unit based on the first correction value, the second correction value and the third correction value. [Effects of the Invention]

[0009] According to embodiments of the present invention, printing defects can be suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] It is a diagram showing an example of the schematic configuration of a tablet printing apparatus according to an embodiment of the present invention. [Figure 2] It is a plan view showing an example of the schematic configuration of a printing apparatus according to an embodiment of the present invention. [Figure 3] It is a diagram showing an example of the schematic configuration of a moving mechanism according to an embodiment of the present invention. [Figure 4] It is a diagram showing an example of the schematic configuration of a control device according to an embodiment of the present invention. [Figure 5] It is a flowchart showing an example of the flow of a position adjustment process according to an embodiment of the present invention. [Figure 6] It is a diagram showing an example of a correction table according to an embodiment of the present invention. [Figure 7] It is a plan view showing Modification 1 of the configuration of a detection unit according to an embodiment of the present invention. [Figure 8] It is a plan view showing Modification 2 of the configuration of a detection unit according to an embodiment of the present invention. [Figure 9] It is a plan view showing Modification 3 of the configuration of a detection unit according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0011] <Embodiment> This embodiment will be described with reference to FIGS. 1 to 9.

[0012] (Configuration Example of Tablet Printing Apparatus) As shown in FIG. 1, the tablet printing apparatus 1 according to this embodiment includes a supply device 10, a first printing device 20, a second printing device 50, a recovery 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 conveyance unit (conveyance device).

[0014] The hopper 11 accommodates a large number of tablets T and sequentially supplies the accommodated tablets T to the alignment feeder 12. The alignment feeder 12 aligns the supplied tablets T in a row and conveys them in the 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 and holds each of the tablets T arranged in a row on the alignment feeder 12 from above the tablets T, and conveys each of the held tablets T in a row 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 the conveying direction A2 (counterclockwise direction). The supply device 10 is electrically connected to the control device 40, and its drive is controlled by the control device 40.

[0015] The first printing device 20 includes a conveying 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 conveying unit 21 functions as a first conveying unit (conveying device). The inkjet head 24 functions as a first inkjet head.

[0016] The conveying unit 21 has a conveying belt 21a, a drive 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 drive pulley 21b and each of the driven pulleys 21c. The drive pulley 21b and each of the driven pulleys 21c are rotatably provided on the device body (not shown), and the drive pulley 21b is connected to the motor 21d. The motor 21d is electrically connected to the control device 40, and its drive 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. This 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 runs the conveying belt 21a together with each of the driven pulleys 21c by the rotation of the drive pulley 21b by the motor 21d, and conveys the tablets T on the conveying belt 21a in the conveying direction A1 (clockwise direction).

[0017] As shown in Figure 2, the conveyor belt 21a has multiple circular suction holes 21g formed therein. Each of these suction holes 21g is a through-hole that attracts a tablet T, and they are arranged in a line along the conveying direction A1 to form a single conveying path. Each suction hole 21g is connected to the suction chamber 21f (see Figure 1) via a suction path (not shown) formed in the suction chamber 21f, and suction force can be obtained from the suction chamber 21f. A pump is connected to the suction chamber 21f via a suction tube (neither shown), and the inside of the suction chamber 21f is depressurized by the operation of the pump. The suction tube is connected to approximately the center of the side surface of the suction chamber 21f (the surface parallel to the conveying direction A1). The pump is also electrically connected to a control device 40, and its drive is controlled by the control device 40. When the inside of the suction chamber 21f is depressurized, tablets T placed on each suction hole 21g of the conveyor belt 21a are attracted through the suction holes 21g and held on the conveyor belt 21a.

[0018] The detection unit 22 is positioned downstream in the transport direction A1 from the location where the supply device 10 is installed, and is located above the transport path where each suction hole 21g is lined up. This detection unit 22 detects the position of the tablet T that has reached the detection position directly below the detection unit 22 (arrival of tablet T), that is, the position of the tablet T on the transport belt 21a in the transport direction A1, by transmitting and receiving laser light. For example, a displacement sensor can be used as the detection unit 22. Various types of laser sensors, such as reflective laser sensors, can be 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 transport direction A1 from the position where the detection unit 22 is located, and is provided above the transport path where each suction hole 21g is lined up. Based on the position information of the tablet T in the transport direction A1 detected by the detection unit 22, the first imaging unit 23 takes an image at a first imaging timing when the tablet T reaches the imaging position directly below the first imaging unit 23, acquiring a first image including the top surface of the tablet T, and transmitting 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, Y, and θ directions (see Figure 2). Various cameras having image sensors such as CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor) can be used as the first imaging unit 23. The first imaging unit 23 is electrically connected to the control device 40, and its drive is controlled by the control device 40. Illumination for imaging is also provided as needed.

[0020] Here, the positions of the tablet T in the X and Y directions are, for example, the positions in the XY coordinate system with respect to the center (reference position) of the imaging area of ​​the first imaging unit 23. The position in the θ direction is, for example, the 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 the tablet T has a score line or when the tablet T is molded into an ellipse, oblong, triangular, or quadrilateral shape. Note that the X and Y directions are positions in the horizontal direction.

[0021] The inkjet head 24 is positioned downstream of the first imaging unit 23 in the transport direction A1 and above the transport path where each suction hole 21g is lined up. The inkjet head 24 has a plurality of nozzles 24a (see Figure 2) (for example, several hundred to several thousand), and the direction in which the nozzles 24a are lined up (nozzle row) is positioned to intersect, for example, orthogonal to, the transport direction A1 in the horizontal plane. The inkjet head 24 ejects ink individually from each nozzle 24a by the operation of a drive element for each nozzle 24a. Various inkjet printing heads having drive elements such as piezoelectric elements, heating elements or magnetostrictive elements can be used as this inkjet head 24. 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 transport direction A1 from the position where the inkjet head 24 is located, and is positioned above the transport path where each suction hole 21g is lined up. Based on the position information of the tablet T in the transport direction A1 detected by the detection unit 22, the second imaging unit 25 takes an image at a second imaging timing when the tablet T reaches the imaging position directly below the second imaging unit 25, acquiring a second image including the top surface of the tablet T, and transmitting the acquired second image to the control device 40. The second image is used to inspect the printed pattern printed on the tablet T. As with the first imaging unit 23 described above, various cameras having image sensors 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 drive is controlled by the control device 40. Illumination for imaging is also provided as needed.

[0023] The drying unit 27 is positioned opposite the conveyor belt 21a, for example, below the conveyor unit 21. This drying unit 27 dries the ink applied to each tablet T on the conveyor belt 21a. Various types of dryers can be used for the drying unit 27, 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 by using both gas and a heater. The drying unit 27 is electrically connected to the control device 40, and its drive is controlled by the control device 40.

[0024] Here, the first printing device 20 and the second printing device 50 are arranged such that individual parts of the transport section 21 and transport section 51 overlap vertically. The tablet T printed by the upper first printing device 20 is transferred to the lower second printing device 50, where both sides of the tablet T are printed. For example, to ensure a smooth transfer of the tablet T from the first printing device 20 to the second printing device 50, the transport speed of the first printing device 20 and the transport 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 comprises a transport unit 51, a detection unit 52, a first imaging unit 53, an inkjet head 54, a second imaging unit 55, and a drying unit 57. The transport unit 51 has a transport belt 51a, a drive pulley 51b, a plurality of driven pulleys 51c, a motor 51d, a position detector 51e, and a suction chamber 51f. This transport unit 51 transports the tablets T on the transport belt 51a in the transport direction A2 (counterclockwise direction). The transport unit 51 functions as a second transport unit (transport device). The inkjet head 54 functions as either a first inkjet head or a second inkjet head. Note that each element constituting the second printing apparatus 50 has basically the same structure as each element constituting the first printing apparatus 20, so their description is omitted.

[0026] The recovery device 30 is located downstream in the transport direction A2 from the location where the drying unit 57 is provided, and is located below the transport unit 51. This recovery device 30 has a reusable product recovery unit 31, a defective product recovery unit 32, and a good product recovery unit 33. The recovery device 30 recovers reusable tablets T by the reusable product recovery unit 31, defective tablets T by the defective product recovery unit 32, and good tablets T by the good product recovery unit 33. For example, reusable products are tablets that can be reused, are undamaged and free of foreign matter, and are non-printed tablets. Defective products include non-printed tablets with foreign matter attached, and undamaged tablets free of foreign matter that are unsuitable for printing (printed tablets), while good products are undamaged tablets free of foreign matter that are suitable for printing (printed tablets). Note that the order in which the reusable product recovery unit 31, the defective product recovery unit 32, and the good product recovery unit 33 are arranged in the transport direction A2 is not limited to the order shown in Figure 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 unit 31 has a spray nozzle 31a and a collection box 31b. The defective product collection unit 32 has a spray nozzle 32a and a collection box 32b. The good product collection unit 33 has a spray nozzle 33a and a collection box 33b. These spray nozzles 31a, 32a, and 33a have basically the same structure, and the collection boxes 31b, 32b, and 33b also have basically the same structure. For this reason, 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 positioned opposite each other across a transport path where the suction holes (corresponding to each suction hole 21g) of the transport belt 51a are lined up. The spray nozzle 31a is located inside the suction chamber 51f and, for example, sprays gas (e.g., air) toward the transport belt 51a, causing the tablets T to fall from the transport belt 51a. At this time, the gas sprayed from the spray nozzle 31a passes through the suction holes of the transport 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 located directly below the spray nozzle 31a and below the transport unit 51. This collection box 31b receives and stores the tablets T that have fallen from the transport belt 51a due to the gas sprayed from the spray nozzle 31a.

[0029] Here, the tablets T that have passed through the recycled product collection section 31 and the defective product collection 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 on the tablets T ceases, but gas is blown 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, the tablets T can be reliably dropped 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 various parts of the tablet printing apparatus 1, such as the supply device 10, the first printing device 20, the second printing device 50, and the collection 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 transport unit 21, and the position detector 51e and detection unit 52 of the transport unit 51, respectively, and also receives image data transmitted from the first imaging unit 23, the second imaging unit 25, the first imaging unit 53, and the second imaging unit 55, respectively. The control device 40 is implemented, for example, by an electronic circuit such as an integrated circuit or a computer.

[0031] (Example of a tablet printing machine's movement mechanism configuration) Next, an example of the configuration of the moving mechanism of the tablet printing device 1 (first moving mechanism 13A, second moving mechanism 24A, third moving mechanism 51A, and fourth moving mechanism 54A) will be explained with reference to Figure 3.

[0032] As shown in Figure 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 a control device 40, and their driving is controlled by the control device 40.

[0033] The first moving mechanism 13A is a mechanism for moving the transfer feeder 13 in the height direction. The second moving mechanism 24A is a mechanism for moving the inkjet head 24 in the height direction. The third moving mechanism 51A is a mechanism for moving the transport unit 51 in the height direction. The fourth moving mechanism 54A is a mechanism for moving the inkjet head 54 in the height direction. The height direction is the vertical direction, and in the example of Figure 3, it is the Z-axis direction.

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

[0035] The conveying unit 21 is fixed (no movement mechanism is provided) and does not move in the height direction in this embodiment. In the example of Figure 3, the reference height position Ba and 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 fixed value. These reference height positions Ba, Bc, and Bb are, for example, predetermined and stored in the storage 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 reference height position Bc) functions 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 way as the transport unit 21 (no movement mechanism is provided), and in this embodiment, it does not move in the height direction. The height position of the alignment feeder 12 is fixed in a state where the height position of the transport surface of the alignment feeder 12 is the same as the height position of the transport surface of the transport unit 21 (adjusted to coincide with the reference height position Ba). Reference height positions are also set for the transfer feeder 13 and the inkjet heads 24 and 54.

[0037] The vertical separation distance B1 between the transfer feeder 13 and the transport unit 21 is adjusted by the transfer feeder 13 moving in the vertical direction by the first moving mechanism 13A. The vertical separation distance B2 between the transport unit 21 and the inkjet head 24 is adjusted by the inkjet head 24 moving in the vertical direction by the second moving mechanism 24A. The vertical separation distance B3 between the transport unit 21 and the transport unit 51 is adjusted by the transport unit 51 moving in the vertical direction by the third moving mechanism 51A. The vertical separation distance B4 between the transport unit 51 and the inkjet head 54 is adjusted by the inkjet head 54 moving in the vertical direction by the fourth moving mechanism 54A. For example, if the fourth moving mechanism 54A is integrally provided with the transport unit 51, the fourth moving mechanism 54A will move together with the movement of the transport unit 51. In this embodiment, the inkjet head 54 and the fourth moving mechanism 54A are described as being integrally provided with the transport unit 51.

[0038] More specifically, the separation distance B1 is the height separation distance between the lower transport surface of the transfer feeder 13 and the upper transport surface of the transport unit 21. This separation distance B1 is adjusted, for example, to ensure smooth transfer of tablets T between the transfer feeder 13 and the transport unit 21. The separation distance B2 is the height separation distance between the upper transport surface of the transport 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 lands properly on the tablets T on the transport unit 21, and so that the tablets T on the transport unit 21 do not collide with the inkjet head 24. In order to suppress the effects of airflow and other factors and ensure that the ink ejected from the inkjet head 24 lands properly on the tablets T on the transport unit 21, it is desirable to bring the ejection surface of the inkjet head 24 closer to the upper surface of the tablets T on the transport unit 21, that is, to shorten the separation distance B2.

[0039] The separation distance B3 is the height separation distance between the lower transport surface of the transport unit 21 and the upper transport surface of the transport unit 51. This separation distance B3 is adjusted, for example, to ensure smooth transfer of tablets T between the transport unit 21 and the transport unit 51. The separation distance B4 is the height separation distance between the upper transport surface of the transport 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 lands properly on the tablets T on the transport unit 51, and so that the tablets T on the transport unit 51 do not collide with the inkjet head 54. As with the separation distance B2 mentioned above, it is desirable to shorten the separation distance B4.

[0040] The transport surface of the aforementioned transfer feeder 13 is the surface on which the tablets T are transported in the transfer feeder 13, and is the lower surface of the transfer feeder 13 (the surface on the transport section 21 side of the transfer feeder 13). The transport surface of the transport section 21 is the surface on which the tablets T are transported in the transport section 21 (transport belt 21a), the upper transport surface of the transport section 21 is the surface on the inkjet head 24 side of the transport section 21, and the lower transport surface of the transport section 21 is the surface on the transport section 51 side of the transport section 21. Similarly, the transport surface of the transport section 51 is the surface on which the tablets T are transported in the transport section 51 (transport belt 51a), and the upper transport surface of the transport section 51 is the surface on the inkjet head 54 side of the transport section 51. In addition, the ejection surface of the inkjet head 24 is the surface on the inkjet head 24 where the nozzles 24a are formed, and is the surface on the transport section 21 side of the inkjet head 24. Similarly, the ejection surface of the inkjet head 54 is the surface on which the nozzle (corresponding to nozzle 24a) is formed in the inkjet head 54, and is the surface of the inkjet head 54 on the transport section 51 side.

[0041] In the example shown in Figure 3, the transport unit 21 is fixed, but it may be configured to be movable by a moving mechanism, similar to the transport unit 51. Similarly, the alignment feeder 12 is fixed, but it may be configured to be movable by a moving mechanism, similar to the transfer feeder 13. However, it is desirable that at least one of the alignment feeder 12, transfer feeder 13, transport unit 21, or transport unit 51 is fixed. When the transport unit 21 and the alignment feeder 12, which are located in the center in the Z direction, are fixed, as in this embodiment, adjusting the height only requires moving the transfer feeder 13 and the transport unit 51 located above and below them. This is preferable because there are fewer components to move compared to cases where only the transfer feeder 13 or only the transport unit 51 is fixed. Furthermore, for example, to simplify the moving mechanism and reduce its size, it is desirable that the transport unit 21, which includes the suction chamber 21f to which the pump is connected via a suction pipe, or the transport unit 51, which includes the suction chamber 51f, be fixed, compared to cases where only the alignment feeder 12 or the transfer feeder 13 is fixed. In other words, it is desirable to fix either the transport unit 21 or the transport unit 51, and it is even more desirable to fix the transport unit 21, which is located in the center in the Z direction.

[0042] Furthermore, in the example shown in Figure 3, the inkjet head 24 is configured to be movable in the height direction by the second moving mechanism 24A. However, if, for example, the detection unit 22, the first imaging unit 23, the inkjet head 24, and the second imaging unit 25 (see Figure 1) are housed in a housing or the like, the housing may be configured to be movable in the height direction by the second moving mechanism 24A. Such a configuration is also applicable to the 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 Figure 4.

[0044] As shown in Figure 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 this control device 40. The input device 40a can be implemented by, for example, a switch, touch panel, keyboard, or mouse. The output device 40b can be implemented by, for example, a display, lamp, or meter.

[0045] The image processing unit 41 acquires 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 known image processing techniques. For example, the image processing unit 41 processes the first image obtained from the first imaging unit 23 to obtain information on whether the tablet T is damaged or has foreign matter attached, and the position of the tablet T in the X, Y, and θ directions. The image processing unit 41 also processes the second image obtained from the second imaging unit 25 to obtain image information of the printed pattern printed on the tablet T. The image processing unit 41 transmits the acquired information on whether the tablet T is damaged or has foreign matter attached, the position information of each tablet T in the X, Y, and θ directions, and the image information of the printed pattern printed on each tablet T to the control unit 43.

[0046] The memory unit 42 stores various programs and information. This memory unit 42 is implemented by, for example, semiconductor memory elements such as RAM (Random Access Memory) and flash memory, or by storage devices such as hard disks and optical discs. The memory unit 42 stores production data (production information), printing data related to printing, transport speed data, etc. Production data refers to data that changes in accordance with the production (manufacturing) of printed tablets T. An example of production data is the lot number. Production data may be generated based on information entered by the user using the input device 40a, or it 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 part. This control unit 43 may be implemented 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 retrieval device 30, the image processing unit 41, the storage unit 42, and the various moving mechanisms 13A, 24A, 51A, 54A, etc., based on various information and programs stored in the storage unit 42. The control unit 43 also receives detection signals transmitted from the position detector 21e and detection unit 22 of the transport unit 21, and the position detector 51e and detection unit 52 of the transport unit 51, respectively.

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

[0049] Furthermore, the control unit 43 sets whether or not the tablet T is printable as printability information based on the information transmitted from the image processing unit 41 in the first printing device 20 regarding the presence or absence of damage or foreign matter (this information is based on the first image). Then, the control unit 43 sets the printing conditions as printability information for the tablet T that has been set to printable. At this time, the control unit 43 sets the printing conditions for the tablet T from which the position information has been obtained, based on the position information of the tablet T in the X, Y, and θ directions transmitted from the image processing unit 41 (this information is 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 to print on 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. If the tablet T has a directional shape, the control unit 43 sets the 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 stores 180 different printing patterns in the storage unit 42, obtained by rotating the orientation of the printing pattern by 1 degree increments from 0 to 179 degrees, and selects a printing pattern with an angle that matches the position of the tablet T in the θ direction from among 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, that is, whether the print pattern has been successfully printed 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 condition check). For example, in determining the shape and size of the print pattern, the control unit 43 registers a print pattern for inspection in the storage unit 42 and compares that print pattern for inspection with the actual print pattern on the tablet T after printing (the print pattern printed on the tablet T).

[0052] Subsequently, the control unit 43 determines that the printing result of the tablet T is good (pass) if it determines that the print pattern for inspection and the print pattern on the actual tablet T after printing match within an acceptable range. On the other hand, the control unit 43 determines that the printing result of the tablet T is poor (fail) if it determines that the print pattern for inspection and the print pattern on the actual tablet T after printing do not match within an acceptable range. Tablets T that are judged to have a poor printing result are discharged by the defective product collection unit 32 (defective product discharge device).

[0053] The various processes in the first printing device 20 described above are also performed by the control unit 43 in the second printing device 50. The control unit 43 stores various information (for example, position information, timing information, printability information, printing condition information, printing quality information, etc.) in the storage unit 42 as appropriate. When the target tablet T is collected by the recovery device 30, the various information is deleted from the storage unit 42 after a predetermined time (for example, a few seconds) has elapsed since it fell from the downstream end of the transport direction A2 in the transport unit 51. However, if this information is needed in subsequent processes, it is possible to leave the various information for each tablet T without deleting it, or to save it on storage media outside the device (external storage). When storing various information for each tablet T, this information may be linked to the manufacturing date and lot number, etc., so that if defective products occur after shipment of printed tablets T, the cause can be traced back to investigate.

[0054] (Position adjustment process) Next, the position adjustment process performed by the aforementioned tablet printing apparatus 1 will be explained with reference to Figure 5. After this position adjustment process is performed, the printing process (including the inspection process) is carried out. 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 performed when either or both of the conveyor belts 21a of the conveyor unit 21 and 51a of the conveyor unit 51 are replaced by the user. For example, the user replaces either or both of the conveyor belts 21a and 51a and instructs the control unit 43 to perform the position adjustment process by inputting an operation on the input device 40a. Note that, since there are usually individual differences in the thickness of the conveyor belts, the thickness of the conveyor belts before and after replacement often differs by about ±1 mm.

[0056] From here, we will explain what the control unit 43 does based on the information input via the input device 40a.

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

[0058] Furthermore, it is not necessary to detect the height change of the conveying surface over the entire circumference of the conveying belt 21a or conveying belt 51a; for example, the height of the conveying surface may be detected at several points or even just one point. However, the more detection points there are, the better the measurement accuracy. Also, for the conveying belts 21a and 51a, the thickness change by the detection unit 22 or detection unit 52 only needs to be measured for the belt that has been replaced. In addition, the reference height positions Ba, Bc, and Bb are measured in advance using the same method and stored in the storage unit 42.

[0059] The detection unit 22 is, for example, a laser sensor. The laser sensor detects the distance from the light-emitting part to the conveying surface of the conveyor belt 21a and sequentially outputs a detected value (detection signal). The laser sensor functions as a sensor that detects the arrival of tablets T by the change in its detected value, but in step S11, it functions as a sensor that detects the height of the conveying surface of the conveyor belt 21a. The same applies to the detection unit 52. In the position adjustment process, before the tablets T are supplied to the hopper 11, that is, when the hopper 11 is empty, the detection units 22 and 52 are turned ON and used to measure the height position of the individual conveying surfaces of the conveyor belts 21a and 51a.

[0060] Alternatively, a mechanism such as a shutter may be provided between the hopper 11 and the alignment feeder 12 to prevent the passage of tablets T, so that tablets T are not supplied beyond the alignment feeder 12, while the height position is measured by the detection unit 22 and the detection unit 52. In short, the height position should be measured by the detection unit 22 and the detection unit 52 when tablets T are not present in the detection target area of ​​the conveyor belt 21a and the conveyor belt 51a.

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

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

[0063] For example, the control unit 43 uses information regarding the change in thickness over one circumference of the conveyor belt 21a (the change in height over one circumference of the conveying surface) to average the thickness over one circumference of the conveyor belt 21a and calculate the average value, and then 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. The height position of the conveyor belt 21a is positive when it increases relative to the reference height position Ba, and negative when it decreases. If the correction value is positive, the conveyor belt 21a moves upward from the reference height position Ba (reference height position Bb), and if the correction value is negative, it moves downward from the reference height position Ba (reference height position Bb). Alternatively, 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 regarding the change in thickness over one circumference of the conveyor belt 51a (the change in height over one circumference of the conveying surface) to average the thickness over one circumference of the conveyor belt 51a and calculate the average value, and based on the calculated average value, calculates the height position of the conveyor belt 51a (the height position of the conveying unit 51). 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. An increase in the height position of the conveyor belt 51a relative to the reference height position Bb is positive, and a decrease is negative. Based on the calculated difference, the positive and negative values ​​of the correction values ​​C1 and C2 are appropriately converted (depending on the direction in which movement is required) and applied (details will be described later). Alternatively, 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 either or both of the conveyor belts 21a and 51a, for example, the height position of the conveying unit 21, i.e., the height position of the upper conveying surface of the conveyor belt 21a, is pre-defined as a reference height position Ba and stored in the storage unit 42, and the height position of the lower conveying surface of the conveyor belt 21a is pre-defined as a reference height position Bc and stored in the storage unit 42. Similarly, the height position of the conveying unit 51, i.e., the height position of the upper conveying surface of the conveying unit 51, is pre-defined as a reference height position Bb and stored in the storage unit 42.

[0066] In step S13, the control unit 43 stores the calculated correction values ​​C1 and C2 in the storage unit 42.

[0067] In step S14, the control unit 43 selects the tablet variety information of the tablet T to be printed, i.e., the tablet variety information, and determines 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 vertical separation distance B1 between the transfer feeder 13 and the transport unit 21, the vertical separation distance B2 between the transport unit 21 and the inkjet head 24, the vertical separation distance B3 between the transport unit 21 and the transport unit 51, and the vertical separation distance B4 between the transport unit 51 and the inkjet head 54. This correction value D1 is a value that optimizes each separation distance B1 to B4 for the type of tablet T.

[0069] For example, the control unit 43 selects tablet variety information in response to a user's input operation to the input device 40a. The tablet variety information includes, for example, one or all of the following: tablet identification information, tablet thickness information, and tablet shape information. The tablet identification information includes, for example, the name and number of tablet T, or both. The tablet thickness information includes, for example, information about the thickness of tablet T, such as several millimeters. The tablet shape information includes, for example, information about the shape of tablet T, such as a disc, triangular disc, elliptical disc, spindle shape, or lens shape. Such tablet variety information is stored in advance in the storage unit 42, for example.

[0070] The control unit 43 may also select the next tablet variety to be produced by receiving information on the next tablet variety transmitted from an external device. Examples of external devices include personal computers, servers, and barcode readers. 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 obtains a correction value D1 from a correction table T1, as shown in Figure 6, based on the selected tablet variety information. This correction table T1 is pre-stored in, for example, the storage unit 42. In the example in Figure 6, the correction table T1 has a correction value D1 for each tablet variety information. The tablet variety information includes a1, b1, and c1..., and the correction value D1 includes a2, b2, c2.... This correction value D1 is set to be the optimal condition for each tablet variety T. Each of a1, b1, and c1... includes, for example, 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, each tablet thickness information, each tablet shape information, or it may be set for information that includes any two or all of the tablet identification information, tablet thickness information, and tablet shape information.

[0072] Tablets T vary in thickness depending on the variety. Furthermore, the variation in thickness also differs. For example, if tablet T is a sugar-coated tablet, there can be a difference of ±0.5 mm in thickness. Since the distance from the top surface of tablet T on the conveyor belt 21a to the ejection surface of the inkjet head 24 is approximately 1 to 1.5 mm, if tablet T is a variety with large individual variations in thickness, the vertical separation distance B2 between the conveyor belt 21a and the inkjet head 24 needs to be set larger than if tablet T is a variety with small individual variations in thickness. This is because, if tablet T is a variety with large individual variations in thickness, setting the vertical separation distance B2 between the conveyor belt 21a and the inkjet head 24 to be the same as for tablet T with small individual variations in thickness could cause tablet T to collide with the inkjet head 24. Taking these factors into consideration, the correction value D1 is set to the optimal condition for each variety of tablet T.

[0073] Furthermore, differences in tablet types T include not only differences in thickness but also differences in shape. There are flat tablets T called "flat tablets" and tablets T with a rounded surface that contacts the conveyor belt 21a, such as sugar-coated tablets, resulting in a variety of tablet shapes T. If the vertical separation distance B1 between the transfer feeder 13 and the conveying section 21, or the vertical separation distance B3 between the conveying section 21 and the conveying section 51, is made too narrow, the curved surface of the tablet T will be strongly squeezed from above and below, resulting in the tablet T shaking, changing its orientation, or continuing to shake. This can lead to printing defects. Taking these factors into consideration, the correction value D1 is set to the optimal condition depending on the type of tablet T.

[0074] In step S15, the control unit 43 stores the obtained correction value D1 in the storage unit 42.

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

[0076] For example, if the difference between the height position of the transport unit 21 and the reference height position Ba is +1.0 mm, and the correction value D1 is +0.5 mm, then the correction value C1 becomes +1.0 mm, and the appropriate height positions for the transfer feeder 13 and the inkjet head 24 are their respective initial positions + 1.5 mm (= 1.0 + 0.5 mm). Therefore, in this case, the transfer feeder 13's moving mechanism 13A and the inkjet head 24's moving mechanism 24A move the transfer feeder 13 and the inkjet head 24 so that they are at a position + 1.5 mm from their respective initial positions stored in the memory unit 42 (a position 1.5 mm higher than the initial position).

[0077] Now, let's explain the correction value C1 applied to the conveying unit 51. Since the difference in the conveying unit 21 is +1.0 mm, the average change in the thickness of the conveying belt 21a is +1.0 mm. In that case, the height position of the conveying belt 21a on the conveying unit 51 side of the conveying unit 21 (the lower conveying surface of 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 also applied. The correction value D1 of +0.5 mm means that each separation distance B1 to B4 is separated by an additional 0.5 mm in addition to the predetermined interval. In that case, in order to separate 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, so the sign of the correction value D1 is made negative, resulting in -0.5 mm. Therefore, the moving mechanism 51A moves the position of the transport section 51 to a position -1.5 mm from the reference height position Bb.

[0078] Furthermore, we will illustrate, for example, the method for calculating the correction value C2 and the correction value D1 (i.e., the amount by which the transport unit 51 is moved) when the difference in the transport unit 21 is +1.0 mm, the difference in the transport unit 51 is +1.5 mm, and the correction value D1 is +0.5 mm.

[0079] The difference in the transport unit 51 is +1.5 mm. This indicates that the average change in the thickness of the transport belt 51a is +1.5 mm. In other words, to correspond to the upper transport surface of the transport belt 51a rising by 1.5 mm, the sign of the correction value C2 is made negative, and the correction value C2 is set to -1.5 mm. In addition to this, the correction value D1 is applied. The correction value D1 of +0.5 mm indicates that the separation distance B1 to B4 is increased by an additional 0.5 mm in addition to the predetermined interval. In that case, in order to further increase the separation distance B3 between the transport unit 21 and the transport unit 51 by another 0.5 mm, the transport unit 51 needs to be lowered, so the sign of the correction value D1 is made negative, resulting in -0.5 mm. Therefore, the appropriate height position for the transport unit 51 is the reference height position Bb - 3 mm (= -1.0 - 1.5 - 0.5 mm). As mentioned earlier, the inkjet head 54 is provided integrally with the transport unit 51. Therefore, the correction value C1 is not considered, and only the correction values ​​C2 and D1 are applied. That is, since the difference in the transport section 51 is +1.5 mm, the inkjet head 54 needs to be raised to secure the separation distance B4, so the correction value C2 becomes +1.5 mm. In addition, the correction value D1 of +0.5 mm is applied, so the appropriate height position for the inkjet head 54 is the initial position (e.g., previous position) + 2 mm (= 1.5 mm + 0.5 mm).

[0080] If the conveyor belt 21a is not replaced, the correction value C1 will be 0. Similarly, if the conveyor belt 51a is not replaced, the correction value C2 will be 0. In detail, when the conveyor belt 21a is replaced, the height position of the conveying unit 21 and the reference height position Ba are usually misaligned, so the correction value C1 is set. However, if the conveyor belt 21a is not replaced, the height position of the conveying unit 21 and the reference height position Ba are not misaligned, so the correction value C1 is set to 0. Likewise, when the conveyor belt 51a is replaced, the height position of the conveying unit 51 and the reference height position Bb are usually misaligned, so the correction value C2 is set. However, if the conveyor belt 51a is not replaced, the height position of the conveying unit 51 and the reference height position Ba are not misaligned, so the correction value C2 is set to 0. Even when the conveyor belts 21a and 51a are not replaced in this way, the correction value D1 is still applied.

[0081] In step S17, the control unit 43 determines the individual movement amounts to the calculated appropriate height position and moves the transfer feeder 13, each inkjet head 24, 54, and transport unit 51 by those movement amounts.

[0082] This position adjustment process ensures that the vertical separation distance B1 between the transfer feeder 13 and the transport unit 21, the vertical separation distance B2 between the transport unit 21 and the inkjet head 24, the vertical separation distance B3 between the transport unit 21 and the transport unit 51, and the vertical separation distance B4 between the transport unit 51 and the inkjet head 54 are appropriately adjusted. As a result, it becomes possible to prevent ink ejected from the inkjet head 24 (or inkjet head 54) from failing to properly land on the tablets T on the transport belt 21a (or transport belt 51a), and to prevent tablets T on the transport belt 21a (or transport belt 51a) from colliding with the inkjet head 24 (or inkjet head 54). Furthermore, it becomes possible to prevent tablets T from falling due to improper transfer between the transport mechanisms such as the transfer feeder 13, transport unit 21, and transport unit 51, and to prevent tablets from shifting position due to the transfer of tablets T. Therefore, printing defects can be suppressed.

[0083] Furthermore, adjusting the height separation distance B1 between the transfer feeder 13 and the conveying unit 21 may result in an inappropriate separation distance between the alignment feeder 12 and the transfer feeder 13. For example, if the height of the transfer feeder 13 is raised to ensure the separation distance B1, the separation distance between the alignment feeder 12 and the transfer feeder 13 may become too large compared to the appropriate separation distance, since the height of the alignment feeder 12 is fixed. In such cases, the height of the end of the transfer feeder 13 on the alignment feeder 12 side may be kept at an appropriate separation distance from the alignment feeder 12, while only the height of the end on the conveying unit 21 side is raised. In other words, the transfer feeder 13 will be installed so as to be inclined. Conversely, if the separation distance between the alignment feeder 12 and the transfer feeder 13 becomes too small, the transfer feeder 13 may be installed so as to be inclined, with the end of the transfer feeder 13 on the alignment feeder 12 side being higher than the end on the conveying unit 21 side.

[0084] (Printing process) Once the aforementioned position adjustment process is complete, 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 loaded into the hopper 11 of the supply device 10, the tablets T are sequentially supplied from the hopper 11 to the alignment feeder 12, where they are arranged in a line and moved. These tablets T moving in a line are sequentially supplied to the conveyor belt 21a of the first printing device 20 by the transfer 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 arranged in a line on the conveyor belt 21a and transported at a predetermined conveying speed.

[0085] The tablets T on the conveyor belt 21a are detected by the detection unit 22. Specifically, when a tablet T on the conveyor belt 21a reaches a detection position directly below the detection unit 22 (for example, the laser beam irradiation position), it is detected by the detection unit 22. Based on the timing of the detection of the tablet T, the control unit 43 recognizes the position of the tablet T in the conveying direction A1 on the conveyor belt 21a. Then, the control unit 43 generates position information indicating the position of the tablet T in the conveying direction A1 and stores it in the storage 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 a first imaging timing when it reaches the imaging position directly below the first imaging unit 23, and the first image obtained by the 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 whether or not there is damage or foreign matter attached to the tablet T, as well as position information of the tablet T in the X, Y, and θ directions, is generated and stored in the storage unit 42.

[0087] Based on information regarding the presence or absence of damage or foreign matter on the tablet T, the control unit 43 determines whether printing is permitted on the target tablet T. If it is determined that printing is permitted on the target tablet T, printing is performed by the inkjet head 24. Based on information such as the position information of the tablet T in the X, Y, and θ directions 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 storage unit 42. Based on the aforementioned printing start timing (the timing at which printing begins on the tablet T), the ejection timing for the tablet T (the timing at which ink is ejected from the tablet T) is determined. On the other hand, if it is determined that printing is not permitted on the target tablet T, operations related to printing and inspection of the target tablet T are restricted. The printability information of the tablet T is stored in the storage unit 42 as appropriate. Note that "restriction" of operations related to printing and inspection means that at least the printing and inspection processes for the target tablet T are 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 printing pattern on the printable tablets T on the transport belt 21a. Specifically, the printable tablets T on the transport belt 21a that have passed below the first imaging unit 23 are printed by the inkjet head 24 based on the aforementioned printing conditions at the printing start timing when they reach the printing position directly below the inkjet head 24. The inkjet head 24 ejects ink appropriately from each nozzle 24a, and the printing pattern is printed on the printable surface, which is the upper surface of the tablet T.

[0089] Next, the printed tablets T on the conveyor belt 21a are imaged by the second imaging unit 25. Specifically, the printed tablets T on the conveyor belt 21a are imaged by the second imaging unit 25 at a second imaging timing when they reach the imaging position directly below the second imaging unit 25, and the second image obtained by the 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. Specifically, the second image is processed by the image processing unit 41 to generate inspection information indicating the printing position, shape, and size of the printed pattern on the tablets T, and this information is stored in the storage unit 42.

[0090] Next, the control unit 43 performs a print condition inspection based on the inspection information described above. Specifically, based on the inspection information related to the print position, shape, and size stored in the memory unit 42, the control unit 43 determines whether or not the print pattern was successfully printed on the tablet T, and print quality information indicating the print quality of the tablet T is generated and stored in the memory unit 42. For example, in the print condition inspection, the print pattern used for printing is stored in the memory unit 42 as an inspection print pattern, and good product information regarding the predetermined print position, shape, and size of the inspection print pattern is compared with the inspection information regarding the print position, shape, and size of the actual printed print pattern stored in the memory unit 42 to determine whether or not the print pattern was successfully printed on the tablet T (pass or fail).

[0091] The aforementioned printing and inspection are repeated in the second printing device 50. The tablets T printed in the first printing device 20 are inverted and passed to the second printing device 50 below, where the aforementioned printing and inspection are performed. This enables double-sided printing on the tablets T. The conveyor belt 51a is rotated in the conveying direction A2 by the rotation of the drive pulley 51b and each driven pulley 51c by the motor 51d. As a result, the tablets T passed onto the conveyor belt 51a are transported in a line on the conveyor belt 51a at a predetermined conveying speed.

[0092] Subsequently, the tablets T on the conveyor belt 51a of the second printing device 50 are collected by the collection device 30. Specifically, when a reusable tablet T reaches the reusable product collection section 31 as the conveyor belt 51a moves, gas is blown onto the tablet T from above by the spray nozzle 31a, causing the tablet T to fall from the conveyor belt 51a and be collected in the collection box 31b. Similarly, when a defective tablet T reaches the defective product collection section 32 as the conveyor belt 21a moves, gas is blown onto the tablet T from above by the spray nozzle 32a, causing the tablet T to fall from the conveyor belt 51a and be collected in the collection box 32b. Furthermore, when a good tablet T reaches a position near the end of the conveyor belt 51a on the side of each driven pulley 51c, the suction effect on the tablet T is lost, and gas is blown onto the tablet T from above by the spray nozzle 33a, causing the tablet T to fall from the conveyor belt 51a and be collected in the collection box 33b. Control over the spraying of such gas is performed by the control unit 43 based on various information, such as the position information of the tablet T, printability information, and print quality information (print condition inspection result information).

[0093] Finally, the control unit 43 determines whether printing is complete or not. For example, the number of printed tablets T is counted, and when that number reaches a predetermined production quantity, it is determined that printing is complete and the process ends. On the other hand, if it is determined that printing is not complete, the aforementioned printing and inspection are repeated. Regarding the determination of printing completion, it may also be determined in response to user input operations to the input device 40a, for example, when the user presses the print completion button.

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

[0095] This allows the separation distance between the transport device and the first inkjet head (for example, the height separation distance B2 between the transport unit 21 and the inkjet head 24, or the height separation distance B4 between the transport unit 51 and the inkjet head 54) to be appropriately adjusted, thereby preventing, for example, ink ejected from the first inkjet head from failing to land properly on the tablet T on the transport device, or the tablet T on the transport device from colliding with the first inkjet head. Therefore, printing defects can be suppressed.

[0096] Furthermore, since the separation distance between conveying devices (for example, the height separation distance B1 between the transfer feeder 13 and the conveying unit 21, or the height separation distance B3 between the conveying unit 21 and the conveying unit 51) is appropriately adjusted, it becomes possible to prevent problems such as tablets T falling due to unsuccessful transfer between conveying mechanisms such as the transfer feeder 13, conveying unit 21, and conveying unit 51, or tablets becoming misaligned due to the transfer of tablets T. Therefore, printing defects can be suppressed.

[0097] Furthermore, the situation in which the distance between the aforementioned conveying device and other conveying devices, i.e., the height distance B3 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, but the height position of the conveying unit 51 changes, i.e., when the conveying belt 21a is not replaced and the conveying belt 51a is replaced (correction value C1=0). If both the conveying belt 21a and the conveying belt 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. However, this can also be rephrased as "printing is performed 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 replaced with a tablet manufacturing apparatus, and the tablet printing method can be replaced with a tablet manufacturing method.

[0099] In the above description, the detection unit 22 is positioned to irradiate light at a location on the line where each suction hole 21g of the conveyor belt 21a is aligned, as shown in Figure 2. However, for example, as shown in Figure 7, it may be positioned to irradiate light at a location shifted by a predetermined distance in the Y-axis direction from that line. In other words, the detection unit 22 may be positioned at a predetermined distance (for example, several mm) from the line where each suction hole 21g is aligned in a plan view. This makes it possible for the detection unit 22 to suppress the effects of light scattering by each suction hole 21g compared to when it irradiates light at a location on the line where each suction hole 21g is aligned, so that, for example, the height of one full rotation of the conveyor belt 21a can be detected with high accuracy. However, the predetermined distance is set so that the detection unit 22 can accurately detect the arrival of the tablet T. The configuration shown in the example in Figure 7 can also be applied to the detection unit 52.

[0100] Furthermore, as shown in Figure 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 full rotation of the conveyor belt 21a. In this case, the detection unit 22 is used only to detect the arrival of the tablet T. The detection unit 22A may have the same configuration as the detection unit 22, or it may have a different configuration from the detection unit 22. In the example of Figure 8, as in the example of Figure 7, it is possible to suppress the effects of light scattering by each suction hole 21g compared to irradiating light at a position on the line where each suction hole 21g is lined up, so that, for example, the height of one full rotation of the conveyor belt 21a can be detected with high accuracy. The configuration in the example of Figure 8 can also be applied to the detection unit 52.

[0101] Furthermore, as shown in Figure 9, the detection unit 22 may be configured to move in a planar direction, for example, in the Y-axis direction, by a moving mechanism 22B. The moving mechanism 22B is, for example, a mechanism that moves the detection unit 22 in 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 where it irradiates light to a position on the line where each suction hole 21g is lined up (initial position) to a position where it irradiates light to a position shifted by a predetermined distance in the Y-axis direction from that line (detection position). After the position adjustment step, the control device 40 moves the detection unit 22 from the detection position to the initial position. Preferably, the detection position is a position where the light irradiated from the detection unit 22 falls within the conveying range on the conveying surface of the conveying belt 21a in which the tablets T are actually conveyed. In the example in Figure 9, as in the examples in Figures 7 and 8, compared to irradiating light onto a line where each suction hole 21g is aligned, it is possible to suppress the effects of light scattering caused by each suction hole 21g, so that, for example, the height of one full rotation of the conveyor belt 21a can be detected with high accuracy. The configuration shown in the example in Figure 9 can also be applied to the detection unit 52.

[0102] Furthermore, although the above explanation uses the example of transporting tablets T in a single row, the system is not limited to this, and the number of rows may be two or more, and the number of transport belts 21a may also be two or more, and is not limited to this. Such a configuration can also be applied to transport belt 51a. Similarly, the number of inkjet heads 24 may also be two or more, and is not limited to this. Such a configuration can also be applied to inkjet head 54.

[0103] Furthermore, in the above description, an inkjet head 24 with nozzles 24a arranged in a single row was given as an example, but it is not limited to this, and for example, an inkjet head with nozzles 24a arranged in multiple rows may be used. Alternatively, multiple inkjet heads 24 may be arranged in a direction perpendicular to the transport direction A1 in the horizontal plane. Such configurations can also be applied to the inkjet head 54.

[0104] Furthermore, in the above description, it was given as an example that the inkjet head 24 is arranged such that the direction in which the nozzles 24a are aligned is perpendicular to the transport direction A1 in the horizontal plane. However, it is not limited to this, and for example, the nozzles 24a may be arranged such that the direction in which they are aligned intersects the transport direction A1 at an angle in the horizontal plane. Such a configuration can also be applied to the inkjet head 54.

[0105] Furthermore, although the above description exemplified a configuration in which the inkjet head 54 and the fourth moving mechanism 54A are integrally provided with the transport unit 51, the invention is not limited to this configuration. For example, the inkjet head 54 may be provided with a moving mechanism 54A separately from the transport unit 51. In this case, when calculating the height position of the inkjet head 54 in step S16 described above, the correction value C1 is used for the calculation.

[0106] Furthermore, although the above description states that the tablets T are supplied randomly rather than at regular intervals on the conveyor belt 21a, the invention is not limited to this, and they may be supplied at regular intervals. Also, although the above description states that the tablets T are held in place by suction holes 21g formed on the conveyor belt 21a, the invention is not limited to this, and they may be held and transported in pockets or the like, or they may be held and transported on the conveyor belt 21a by their own weight. Such configurations are also applicable to the conveyor belt 51a.

[0107] Here, the aforementioned tablet T can include tablets used for pharmaceutical, edible, cleaning, industrial, or fragrance purposes. Furthermore, tablet T can include uncoated tablets, sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-coated tablets, multilayer tablets, and core tablets, and various types of capsule tablets such as hard capsules and soft capsules can also be included in tablet T. In addition, tablet T can take various shapes such as disc-shaped, lens-shaped, triangular, and oval. Moreover, if the tablet T to be printed is for pharmaceutical or edible purposes, edible ink is preferable as the ink used. This edible ink can be any of synthetic dye ink, natural dye ink, dye ink, or pigment ink.

[0108] Although several embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0109] 1. Tablet printing device 10 Feeding device 11 Hoppa 12 Alignment Feeders 13 Transfer Feeder 13A First moving mechanism 20 First Printing Apparatus 21 Conveying section 21a Conveyor belt 21b Drive pulley 21c Driven pulley 21d motor 21e Position detector 21f Suction Chamber 21g suction hole 22 Detection unit 22A Detection Unit 22B Moving mechanism 23 First imaging unit 24 inkjet heads 24A Second moving mechanism 24a Nozzle 25 Second imaging unit 27 Drying section 30 Recovery device 31. Recyclable Materials Collection Department 31a Spray nozzle 31b Collection box 32 Defective Product Collection Department 32a Spray nozzle 32b Collection Box 33. Good Product Collection Department 33b Collection Box 33a Spray nozzle 40 Control device 40a Input device 40b Output device 41 Image Processing Unit 42 Storage section 43 Control Unit 50 Second printing device 51 Conveying section 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 heads 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 transporting tablets, A first inkjet head for printing on the tablets being transported by the transport device, and a moving mechanism for moving at least one of the transport device and the first inkjet head in the height direction. A control device for controlling the aforementioned moving mechanism, Equipped with, The aforementioned transport device is A first transport unit for transporting the tablets printed by the first inkjet head, The system comprises a supply and transport unit that delivers the tablets to the first transport unit, The moving mechanism moves the first inkjet head and the supply transport unit in the height direction. The control device is A first correction value is generated based on the difference between the height position of the first transport unit and the first reference height position. A second correction value is generated based on the tablet variety information relating to the variety of the aforementioned tablets. The movement mechanism is controlled based on the first correction value and the second correction value. Tablet printing machine.

2. A conveying device for conveying tablets, A first inkjet head for printing on the tablets being transported by the transport device, A moving mechanism for moving at least one of the transport device and the first inkjet head in the height direction, A control device for controlling the aforementioned moving mechanism, Equipped with, The first inkjet head prints on one side of the tablet. The system further comprises a second inkjet head for printing on the other side of the tablet printed by the first inkjet head, The aforementioned transport device is A first transport unit for transporting the tablets printed by the first inkjet head, A second transport unit for transporting the tablets printed by the second inkjet head, A supply and transport unit that delivers the tablets to the first transport unit, It has, The aforementioned moving mechanism further includes a mechanism for moving at least one of the transport device and the second inkjet head in the height direction. The control device is A first correction value is generated based on the difference between the height position of the first transport unit and the first reference height position. A second correction value is generated based on the tablet variety information relating to the variety of the aforementioned tablets. A third correction value is generated based on the difference between the height position of the second transport unit and the second reference height position. Based on the first correction value and the second correction value, the moving mechanism adjusts the relative height position between the supply transport unit and the first transport unit, and the relative height position between the first inkjet head and the first transport unit. Based on the first correction value, the second correction value, and the third correction value, the moving mechanism adjusts the relative height position between the first transport unit and the second transport unit, and the relative height position between the second inkjet head and the second transport unit. Tablet printing machine.

3. The system further includes a detection unit for detecting the arrival of the aforementioned tablets, The control device measures the height position of the transport device based on the detection result of the detection unit. The tablet printing apparatus according to claim 1 or 2.

4. The tablet variety information includes any or all of the following: the tablet identification information, the tablet thickness information, and the tablet shape information. The tablet printing apparatus according to claim 1 or 2.

5. The control device A first correction value is generated based on the difference between the height position of the first transport unit that transports tablets and the first reference height position, A second correction value is generated based on tablet variety information relating to the variety of the aforementioned tablets, Based on the first and second correction values, the system controls the movement mechanism that moves the first inkjet head, which prints on one side of the tablet being transported to the first transport unit, and the supply transport unit, which delivers the tablet to the first transport unit, in the height direction. including, Tablet printing method.

6. The control device is A first correction value is generated based on the difference between the height position of the first transport unit that transports tablets passed from the supply transport unit and the first reference height position, A second correction value is generated based on tablet variety information relating to the variety of the aforementioned tablets, A third correction value is generated based on the difference between the height position of the second transport unit that transports the tablets passed from the first transport unit and the second reference height position, A transport device including the supply transport unit, the first transport unit, and the second transport unit, and an inkjet head including a first inkjet head that prints on one side of the tablet transported to the first transport unit and a second inkjet head that prints on the other side of the tablet transported to the second transport unit, wherein at least one of these is moved in the height direction by a moving mechanism, The movement by the aforementioned moving mechanism is Based on the first correction value and the second correction value, the relative height position between the supply transport unit and the first transport unit, and the relative height position between the first inkjet head and the first transport unit are adjusted. Based on the first correction value, the second correction value, and the third correction value, the relative height positions of the first transport unit and the second transport unit are adjusted, and the relative height positions of the second inkjet head and the second transport unit are adjusted. including, Tablet printing method.

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