JP2020096808A - Tablet printing device - Google Patents

Abstract

To provide a tablet printing device capable of suppressing deterioration in productivity caused by a printing stop accompanying maintenance of a print head.SOLUTION: A tablet printing device includes: two conveyance belts 21 which convey tablets T and which function as at least two conveyance routes; a liquid reception unit 71 which is provided between the two conveyance belts and which functions as a maintenance unit for performing maintenance; a print head 51 which is provided above the conveyance belts for each conveyance belt and around the liquid reception unit, which discharges a liquid from a nozzle by an inkjet method; and a moving device 72 for individually moving each print head to a printing position above the conveyance belt for each print head, and a maintenance position above the liquid reception unit for each print head.SELECTED DRAWING: Figure 3

Description

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

2. Description of the Related Art In order to print identification information such as characters and symbols on tablets, a technique of printing using an inkjet print head is known. A tablet printing apparatus using this technique conveys a plurality of tablets in a row by a conveyor, and ink (e.g., an acceptable ink) is ejected from a nozzle of an inkjet print head arranged above the conveyor to a tablet passing below the print head. The edible ink) is discharged and the identification information is printed on the tablets on the conveyor.

In this tablet printing apparatus, if air bubbles or dust are present in the flow path in the inkjet print head, they cause ejection failure. Further, when the ink that is easily dried is used as the printing ink, the viscosity of the ink in the nozzle may be increased, or the solid matter may be deposited, which causes ejection failure. The occurrence of such ejection failure leads to deterioration of print quality.

Therefore, maintenance (dummy ejection or pressure feeding) for discharging ink from the nozzles of the print head is regularly performed, and the print head is maintained in a normal state. Normally, it is necessary to stop the transportation of tablets each time the print head needs maintenance. During this suspension period, printing on the tablets is interrupted, which causes a problem of reduced productivity. It is possible to improve the productivity by transporting the tablets in multiple rows, but there are still the same problems.

JP-A-7-081050

The problem to be solved by the present invention is to provide a tablet printing apparatus capable of suppressing a decrease in productivity due to a print stop due to maintenance of a print head.

The tablet printing apparatus according to the embodiment of the present invention includes at least two transport paths through which tablets are transported, a maintenance unit provided between the two transport paths and performing maintenance, and a transport path for each transport path. Above the printer and around the maintenance unit, the inkjet print head that ejects liquid from the nozzles, the print position above the transport path for each print head, and the print position above the maintenance unit for each print head. And a moving device for individually moving the head.

The tablet printing apparatus according to the embodiment of the present invention includes at least two transport paths through which tablets are transported, a maintenance unit provided between the two transport paths and performing maintenance, and a transport path for each transport path. Of the inkjet type, which is provided above the maintenance unit and around the maintenance unit and discharges the liquid from the nozzles, and the print heads are disposed at the printing position above the transport path for each print head and the plurality of maintenance positions above the maintenance unit. And a moving device for moving. The print heads are arranged in the transport direction of two or more tablets for each transport path, and the maintenance position is provided for each set of print heads aligned in the direction intersecting the transport direction. Each print head is individually moved so as to share the maintenance position for each group.

The tablet printing apparatus according to the embodiment of the present invention includes at least two transport paths through which tablets are transported, a maintenance unit provided between the two transport paths and performing maintenance, and a transport path for each transport path. Of the inkjet type, which is provided above the maintenance unit and around the maintenance unit and discharges the liquid from the nozzles, and the print heads are disposed at the printing position above the transport path for each print head and the plurality of maintenance positions above the maintenance unit. And a moving device for moving. The print heads are arranged in a direction that intersects the transport direction of the tablets for each transport path, and the maintenance position is provided for each set of two or more print heads. Each print head is moved for each set of print heads so as to share the maintenance position for each set.

According to the embodiment of the present invention, it is possible to prevent the productivity from decreasing due to the stop of printing accompanying the maintenance of the print head.

It is a figure which shows schematic structure of the tablet printing apparatus which concerns on 1st Embodiment. It is a top view showing a part of tablet printing device concerning a 1st embodiment. It is a top view which expands and shows a part of tablet printing apparatus which concerns on 1st Embodiment. It is a top view which expands and shows a part of tablet printing apparatus which concerns on 2nd Embodiment. It is a top view which expands and shows a part of tablet printing apparatus which concerns on 3rd Embodiment. It is a figure which shows schematic structure of the maintenance apparatus which concerns on 4th Embodiment. It is a figure which shows schematic structure of the maintenance apparatus which concerns on 5th Embodiment. It is a figure which shows schematic structure of the maintenance apparatus which concerns on 6th Embodiment. It is a figure which shows schematic structure of the maintenance apparatus which concerns on 7th Embodiment. It is a figure which shows schematic structure of the maintenance apparatus which concerns on 8th Embodiment. It is a figure which shows schematic structure of the modification of the maintenance apparatus which concerns on 8th Embodiment. It is a figure which shows schematic structure of the modification of the maintenance apparatus which concerns on 2nd Embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

(Basic configuration)
As shown in FIGS. 1 and 2, the tablet printing apparatus 1 according to the first embodiment includes a supply device 10, a transport device 20, a detection device 30, an imaging device 40, a printing device 50, and a collection device. 60, a maintenance device 70, an image processing device 80, and a control device 90.

The supply device 10 includes a hopper 11 and a shooter 12. The hopper 11 accommodates a large number of tablets T and sequentially supplies the accommodated tablets T to the shooter 12. The shooter 12 aligns the supplied tablets T in a plurality of rows and supplies the tablets T to the carrying device 20. The supply device 10 is electrically connected to the control device 90, and its drive is controlled by the control device 90.

The transport device 20 includes two transport belts 21 (see FIG. 2), a drive pulley 22, a driven pulley 23, and a drive unit 24. Each of the conveyor belts 21 is formed in an endless shape, and is stretched over a driving pulley 22 and a driven pulley 23 in parallel with each other. The drive pulley 22 and the driven pulley 23 are rotatably provided around the shaft, and the drive pulley 22 is connected to the drive unit 24. The drive unit 24 is electrically connected to the control device 90, and its drive is controlled by the control device 90. The drive unit 24 includes a position detector 24a such as a rotary encoder. The position detector 24a transmits a detection signal to the control device 90. The control device 90 can obtain information such as the position, speed, and movement amount of each of the conveyor belts 21 based on the detection signal. The transport device 20 has two transport paths with the two transport belts 21.

This transport device 20 rotates each transport belt 21 together with the driven pulley 23 by the rotation of the drive pulley 22 by the drive unit 24, and the tablets T on these transport belts 21 are indicated by the arrow A1 (transport direction in FIGS. 1 and 2). Transport to A1). It should be noted that each of the conveyor belts 21 is formed with linear slit-shaped suction ports 21a (see FIG. 2) in two rows along the conveying direction A1. The two suction ports 21a are connected to a suction device (neither is shown) via a suction chamber, and a suction force is obtained by driving the suction device (for example, a suction pump). The tablet T supplied onto the suction port 21a is held on the conveyor belt 21 by the suction of the suction port 21a.

The detection device 30 includes a plurality of detection units 31 (see FIG. 2). Two detectors 31 are provided above the conveyor belts 21 for each conveyor belt 21. These detection units 31 are positioned downstream of the supply device 10 in the transport direction A1 and above the two rows of suction ports 21a, and are arranged in a direction intersecting the transport direction A1 in a horizontal plane (for example, a direction orthogonal to each other). Has been. Each detection unit 31 detects the tablets T on the conveyor belt 21 by projecting and receiving laser light. These detection units 31 are electrically connected to the control device 90 and transmit detection signals to the control device 90. As the detection unit 31, for example, various laser sensors (laser displacement meters) such as a reflective laser sensor can be used. Further, various shapes such as spots and lines can be used as the beam shape of the laser light.

The imaging device 40 includes a plurality of imaging units 41 (see FIG. 2). Two imaging units 41 are provided above the conveyor belts 21 for each conveyor belt 21. These imaging units 41 are positioned downstream of the detection device 30 in the transport direction A1 and above the two rows of suction ports 21a, and are arranged in a direction intersecting the transport direction A1 in the horizontal plane (for example, a direction orthogonal to each other). Has been. The imaging field of the imaging unit 41 has a size such that only one tablet T conveyed by the conveyor belt 21 enters the imaging field and neither the tablet T on the upstream side or the downstream side in the conveyance direction A1 nor the tablet T in the adjacent row enters. Is set to The image capturing unit 41 captures an image at the timing when the tablet T reaches directly below, acquires an image including the upper surface of the tablet T, and transmits the acquired image to the image processing device 80. As the imaging unit 41, for example, various cameras having an imaging device such as CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) can be used. Each imaging unit 41 is electrically connected to the control device 90 via the image processing device 80, and their drive is controlled by the control device 90. Illumination for imaging is also provided as needed.

The printing apparatus 50 includes a plurality of inkjet type print heads 51. Each of the print heads 51 is provided above the transport belt 21 for each of the transport belts 21 and is positioned downstream of the imaging device 40 in the transport direction A1. These print heads 51 are arranged so as to be offset from each other in the transport direction A1 by a predetermined distance (for example, a distance longer than the width of the print head 51 in the transport direction A1) so as not to interfere with each other's movement with respect to the maintenance device 70. Has been done. The print head 51 includes a plurality of nozzles 51a (see FIG. 2), and ejects ink (an example of a liquid) individually from the nozzles 51a. The print head 51 is provided such that the nozzle alignment direction in which the nozzles 51a are arranged intersects (for example, is orthogonal to) the transport direction A1 in the horizontal plane. As the print head 51, it is possible to use, for example, various inkjet print heads having a driving element such as a piezoelectric element, a heating element, or a magnetostrictive element. The print head 51 is electrically connected to the control device 90, and its drive is controlled by the control device 90.

The collecting device 60 is positioned downstream of the printing device 50 in the transport direction A1, and is provided at an end of the transport device 20, that is, an end of each of the transport belts 21 on the downstream side of the transport direction A1. The collecting device 60 is configured to be able to sequentially receive and collect the tablets T that are released from the holding by the respective conveyor belts 21 and fall. The transport device 20 releases the holding of the tablets T when the individual tablets T on the respective transport belts 21 reach a desired position, for example, the end of each transport belt 21 on the downstream side in the transport direction A1. ..

The maintenance device 70 includes a liquid receiving portion 71 and a moving device 72, as shown in FIG. Note that the moving device 72 is omitted in FIGS. 1 and 2 for simplification of the drawings.

The liquid receiving portion 71 is formed, for example, in the shape of a box having an open top, and is provided between two adjacent conveyor belts 21. The liquid receiving portion 71 receives the ink ejected from each nozzle 51a of the print head 51 which is opposed at the time of maintenance. The upper end of the liquid receiving portion 71 is located lower than the upper surface of the transport belt 21 so as not to hinder the movement of the print head 51. The width of the liquid receiving portion 71 in the direction orthogonal to the transport direction A1 is substantially the same as the width of the print head 51 in the same direction (almost the same as the width of one head, and at least the width of two heads). Too short). The print heads 51 exist around the liquid receiving portion 71, and the print heads 51 are provided above the transport belt 21 so as to be close to the liquid receiving portion 71 for each transport belt 21. There is. Here, the two conveyor belts 21 are separated from each other by a predetermined distance, that is, a distance at which the maintenance device 70 can be installed. This separation distance is maintained at a predetermined distance. This is because each of the conveyor belts 21 may be removed when the two conveyor belts 21 are maintained, but the conveyor belts 21 may only be removable from the same direction (one direction).

The moving device 72 has a pair of moving mechanisms 72a and 72b and a pair of support bases 72c and 72d. The pair of moving mechanisms 72a and 72b are positioned on the downstream side of the imaging device 40 in the transport direction A1, and are provided above the transport belts 21 and the liquid receiving portions 71 so as to be along a direction orthogonal to the transport direction A1 on a horizontal plane. ing. The pair of support bases 72c and 72d are arranged in a direction orthogonal to the transport direction A1 so as to sandwich the transport device 20, and support both ends of the pair of moving mechanisms 72a and 72b. Each of the moving mechanisms 72a and 72b movably supports the print head 51 in a direction orthogonal to the transport direction A1, and the print head 51 faces the liquid receiving portion 71 at a maintenance position and a print position that faces the transport belt 21. The print head 51 is moved to (application position). The pair of moving mechanisms 72a and 72b are electrically connected to the control device 90, and the drive thereof is controlled by the control device 90.

Here, the maintenance position is a position where the print head 51 ejects ink toward the liquid receiving portion 71. Two maintenance positions are provided for each print head 51, and two maintenance positions are provided above the liquid receiving portion 71. These maintenance positions are lined up along the transport direction A1. Further, the printing position is a position for ejecting ink toward the tablets T conveyed by the conveyor belt 21. This printing position is provided for each print head 51, and there are two printing positions above the first conveyor belt 21 and above the second conveyor belt 21. These print positions are displaced by a predetermined distance in the transport direction A1. That is, in FIG. 3, the position of the print head 51 indicated by the solid line on the conveyor belt 21 is the print position, and the position of the print head 51 indicated by the broken line on the liquid receiving portion 71 is the maintenance position.

The image processing device 80 captures each image captured by the imaging device 40, processes each image using a known image processing technique, and shifts the position of the tablet T in the X direction, the Y direction, and the θ direction (rotational direction). Is detected (see FIG. 3). Here, the positional displacement in the X direction and the Y direction is the positional displacement of the tablet T with respect to the center of the imaging visual field, and it is detected how much the tablet T is displaced with respect to the center. In the present embodiment, as an example, the transport direction A1 of the tablet T is the X direction, and the direction orthogonal to the transport direction A1 is the Y direction.

The positional deviation in the θ direction is rotational deviation of the tablet T in the horizontal plane. This misalignment in the θ direction occurs when the tablet T has a directionality, such as when the tablet T is provided with a dividing line or when the tablet T is molded into an elliptical shape, an oval shape, a square shape, or the like. To be detected. For example, when the score line is formed on the tablet T, the θ shift is calculated in 1 degree units in the range of 0 degree to 179 degree with 0 degree when the direction of the score line is parallel to the Y direction. To do. Further, when the shape of the tablet T is not line-symmetric with respect to the dividing line, the θ deviation may be obtained in the range of 0 degrees to 359 degrees. If the tablet T has no orientation, it is not necessary to detect the θ deviation.

The image processing device 80 transmits the detected positional deviation information of each tablet T in the X direction, the Y direction, and the θ direction to the control device 90. When the image processing device 80 transmits the positional shift information, the positional shift information is added with the identification information of each imaging unit 41 and transmitted. As a result, the control device 90 recognizes that the transmitted positional deviation information is the positional deviation information of the tablet T located in which row among the tablets T conveyed in four rows by the two conveyor belts 21. can do.

The control device 90 includes a microcomputer that centrally controls each unit, and a storage unit (not shown) that stores processing information and various programs. The control device 90 controls the supply device 10, the transport device 20, the imaging device 40, and the printing device 50 based on various information and various programs. The control device 90 also receives a detection signal transmitted from the detection device 30 or the position detector 24a, an image transmitted from the imaging device 40, and the like.

Further, the control device 90 detects the positional deviation in the X direction, the Y direction, and the θ direction based on the positional deviation information in the X direction, the Y direction, and the θ direction of each tablet T transmitted from the image processing device 80. The printing conditions for the tablet T are set. In the storage unit, print data including print patterns such as characters and symbols to be printed on the tablet T and data such as print positions of the characters and symbols on the tablet T, and the transport belts 21. Moving speed information and the like are stored.

For example, the control device 90 determines the usage range of the nozzles 51a used for the current printing in the print head 51 based on the positional deviation in the Y direction. As an example, among the plurality of nozzles 51a included in the print head 51, it is assumed that five nozzles 51a are used for applying the tablets T, and the amount of positional deviation of the tablets T in the Y direction is one pitch of the arrangement interval of the nozzles 51a. In such a case, the printing condition is set so that the five nozzles 51a are used by shifting the use range of the nozzles 51a by one pitch in the direction in which the tablets T are displaced.

Further, the control device 90 determines the timing to start printing on the tablet T based on the positional deviation in the X direction. For example, when the tablet T is displaced by the distance ΔX on the upstream side in the conveying direction A1, the time required for the conveyor belt 21 to move the distance ΔX as compared with the case where the tablet T is not displaced in the X direction. The printing conditions are set so that printing is started at a timing delayed by just that.

Further, the control device 90 sets the printing condition in which the tablet T is rotated in accordance with the rotational displacement of the tablet T based on the positional displacement in the θ direction. For example, in the storage unit of the control device 90, 180 kinds of print data obtained by rotating the orientations of print patterns such as characters and symbols one by one in the range of 0 to 179 degrees are registered, and the print data of those print data is registered. Print data having an angle suitable for the detected positional deviation in the θ direction is selected from the inside to set print conditions.

(Printing process)
Next, a printing process (printing process) performed by the tablet printing apparatus 1 will be described.

First, various information such as print data required for printing is stored in the storage unit of the control device 90. Further, a large number of tablets T to be printed are put into the hopper 11 of the supply device 10. When the tablet printing apparatus 1 is driven, each transport belt 21 of the transport device 20 rotates in the transport direction A1 as the drive pulley 22 and the driven pulley 23 rotate by the drive unit 24. While each conveyor belt 21 is rotating, the tablets T are sequentially supplied from the supply device 10 onto each conveyor belt 21 at random rather than at regular intervals. The tablets T are arranged in two rows for each of the conveyor belts 21 and conveyed at a predetermined moving speed.

The individual tablets T on each conveyor belt 21 are detected by each detector 31 for each conveyor belt 21, and each detection signal from each detector 31 is input to the control device 90 as a trigger signal. After that, the individual tablets T on the respective conveyor belts 21 are imaged by the respective imaging units 41 for the respective conveyor belts 21. The upper surface of the tablet T is imaged by the imaging unit 41 at the timing based on the above trigger signal, that is, the timing when the tablet T reaches below the imaging unit 41, and the captured image is transmitted to the image processing device 80. Based on the individual images transmitted from each imaging unit 41, the positional deviation information of the tablet T (for example, positional deviation of the tablet T in the X direction, the Y direction, and the θ direction) is generated by the image processing device 80, and the control device. 90. The printing condition for the tablet T is set by the control device 90 based on the positional deviation information of the tablet T.

After that, the individual tablets T on each conveyor belt 21 are printed by the printing device 50 based on the above-described printing conditions at the timing based on the trigger signal described above, that is, at the timing when the tablets T reach below the print head 51. Executed. In each print head 51 of the printing device 50, ink is appropriately ejected from each nozzle 51a, and identification information such as characters and marks is printed on the upper surface of the tablet T. The ink applied to the tablets T is dried before the tablets T are recovered by the recovery device 60. When the tablet T with the dried ink is positioned at the downstream end of each conveyor belt 21, the tablet T is released from the state of being held by each conveyor belt 21, falls from each conveyor belt 21, and is recovered by the recovery device 60. ..

(Maintenance process)
In such a printing process, the maintenance operation for the print head 51 is regularly performed for a predetermined time. When the maintenance operation is dummy ejection (when ink is ejected from the nozzle 51a by the ejection operation), the dummy ejection execution interval is, for example, 10 to 20 minutes, and the dummy ejection time is 1 to 5 seconds. It's a few seconds. When the maintenance operation is pressure feeding (when ink is ejected from the nozzle 51a by pressurization), the pressure feeding execution interval is, for example, 30 to 40 minutes, and the pressure feeding time is a number such as 30 to 60 seconds. It's ten seconds. Here, since the pressure feeding time is longer than the dummy ejection time, in order to reduce the stop time of printing due to the maintenance of the print head 51, the number of maintenances by dummy ejection is increased and the number of maintenances by pressure feeding is reduced. Is desirable. Therefore, by shortening the dummy discharge execution interval and increasing the pressure feed execution interval, it is possible to shorten the printing stop time due to the maintenance of the print head 51. Further, since the amount of ink used during dummy ejection is much smaller than the amount of ink used during pressure feeding, the amount of ink used for maintenance can be suppressed. Further, as maintenance, wiping may be performed to wipe off excess ink adhering to the nozzle surface of the print head 51.

In the maintenance process, the driving of each conveyor belt 21 is not stopped, the supply of the tablets T to the conveyor belts 21 is stopped by the supply device 10, and the maintenance of each print head 51 is executed. Specifically, after the supply of the tablets T is stopped, the unprinted tablets T that have not reached below the print head 51 on the transport belt 21 sequentially reach below the print head 51 for each of the transport belts 21 and the print head 51. Will be printed by. After the printing is completed, each print head 51 is moved by the moving device 72 to the maintenance position facing the liquid receiving portion 71. Each print head 51 that has moved to the maintenance position performs dummy ejection or pressure feeding for a predetermined time. After the maintenance operation is completed, each print head 51 is moved by the moving device 72 to the original print position facing the transport belt 21. After that, the supply of the tablets T is restarted by the supply device 10, and the printing is restarted by each print head 51 that has moved to the printing position. The maintenance start timing of each print head 51 may be the same or may be shifted.

According to such a maintenance process, the supply of the tablets T is stopped for maintenance, but the stop time is suppressed. Since the movement distance at the time of maintenance of both of the two print heads 51 is almost the shortest, the movement time of each print head 51 can be shortened.

As described above, according to the first embodiment, the liquid receiving portion 71 that functions as the maintenance portion of the maintenance device 70 is provided between the two conveyor belts 21, and the two print heads 51 are the print heads. For each 51, the moving device 72 moves to a printing position for ejecting ink (an example of liquid) toward the tablets T conveyed by the conveyor belt 21 and a maintenance position for ejecting ink toward the liquid receiving portion 71. To do. As a result, the moving distance of both the two print heads 51 at the time of maintenance is shortened as compared with the case where one liquid receiving portion 71 is provided outside one of the two transport belts 21 and not on the other. The moving time of each print head 51 can be shortened. As a result, the printing stop time due to the maintenance of the print head 51 is shortened, so that it is possible to prevent the productivity from decreasing due to the print stop. Further, by providing the liquid receiving portion 71 between the two transport belts 21, the liquid receiving portion 71 is provided with a single liquid receiving portion 71 as compared with the case where the liquid receiving portion 71 is provided outside each of the two transport belts 21. Therefore, the tablet printing apparatus 1 can be downsized.

Although the print heads 51 are offset from each other in the transport direction A1 as described above, the present invention is not limited to this, and the print heads 51 may not collide on the liquid receiving portion 71. Therefore, the print heads 51 for the respective conveyor belts 21 may be positioned on the same straight line, and oblique or curved movement paths may be provided so that the movement paths of the print heads 51 do not overlap. Even if the movement paths of the print heads 51 overlap, the timing may be shifted so that the print heads 51 do not go into maintenance at the same timing.

(Second embodiment)
The second embodiment will be described with reference to FIG. In the second embodiment, differences from the first embodiment (number of print heads and maintenance process) will be described, and other description will be omitted.

As shown in FIG. 4, in the second embodiment, four print heads 51 are provided, and there are four print positions. Here, for simplification of description, the four print heads 51 are distinguished as a first print head 51, a second print head 51, a third print head 51, and a fourth print head 51, and in FIG. The reference numerals 1, 2, 3 and 4 are written on the four print heads 51.

The first print head 51 and the second print head 51 are arranged in the X direction so as to be parallel to each other. Further, the third print head 51 and the fourth print head 51 are also arranged in the X direction so as to be parallel to each other. The first print head 51 and the third print head 51 are individually moved in the Y direction by the moving mechanism 72a. The second print head 51 and the fourth print head 51 are individually moved in the Y direction by the moving mechanism 72b. The first print head 51 and the third print head 51 are in a group that shares one maintenance position, and the second print head 51 and the fourth print head 51 are in a group that share one maintenance position. ..

In the first maintenance process (alternate printing), the first print head 51 and the second print head 51 do not perform printing at the same time, and when either one is performing printing, the other is performing maintenance. To do. Similarly, the third print head 51 and the fourth print head 51 do not perform printing at the same time, and when either one is performing printing, the other is performing maintenance. Further, the print heads 51 of the set that share the maintenance position do not perform printing at the same time.

For example, when a predetermined time elapses after the first print head 51 and the fourth print head 51 start printing, the first print head 51 and the fourth print head 51 stop printing and stand by with them. The second print head 51 and the third print head 51 start printing. When the switching of the print heads 51 is completed, the first print head 51 and the fourth print head 51 move from the print positions to the maintenance positions and start maintenance. After that, when the maintenance is completed, the first print head 51 and the fourth print head 51 respectively move from the maintenance position to the printing position and stand by for the next printing.

Then, when a predetermined time elapses after the second print head 51 and the third print head 51 start printing, the second print head 51 and the third print head 51 stop printing and wait with it. The first print head 51 and the fourth print head 51 start printing. After the switching of the print heads 51 is completed, the second print head 51 and the third print head 51 move from the print positions to the maintenance positions and start the maintenance. After that, when the maintenance is completed, the second print head 51 and the third print head 51 respectively move from the maintenance position to the printing position and stand by for the next printing. Such an operation is repeated.

The maintenance is executed every predetermined time, but the predetermined time in the first maintenance process is set to a time at which the print head 51 waiting at the printing position can print as it is. For example, while the first print head 51 is printing, the second print head 51 is waiting at the print position. If this waiting time becomes long, the ink in each nozzle 51a of the second print head 51 may dry, and ejection failure may occur. Therefore, the above-mentioned predetermined time is experimentally or theoretically set in advance so that the ejection failure does not occur. However, the predetermined time does not necessarily have to be set as described above. For example, when the print head 51 waiting at the print position performs printing, the print head 51 moves to the maintenance position before the printing, and dummy ejection is performed. It is also possible to return to the printing position and start printing. Further, since the print heads 51 of the group that share the maintenance position do not execute the printing at the same time, the print heads 51 of the respective conveyor belts 21 do not move to the maintenance position at the same time, and those print heads 51 do not move to the maintenance position. Will not collide with.

In the second maintenance process (all printing), each print head 51 prints together. The first print head 51 and the second print head 51 alternately perform printing every predetermined time (for example, 1 minute). Similarly, the third print head 51 and the fourth print head 51 also perform printing alternately every predetermined time (for example, 1 minute). The controller 90 selects a maintenance target from each of the print heads 51 based on the number of times of driving, and the maintenance for the selected print head 51 is executed. Since the intervals at which the tablets T are conveyed are not constant, the usage frequency of each print head 51 is different.

The control device 90 is capable of grasping the number of times each print head 51 is individually driven (for example, the number of times the drive element has been driven), and prints that are subject to maintenance according to the number of times each print head 51 is driven. The head 51 is selected. For example, among the print heads 51, the print head 51 that has been driven a predetermined number of times is set as the print head 51 to be maintained. However, the control device 90 does not set the first print head 51 and the second print head 51 as maintenance targets at the same time, and does not set the third print head 51 and the fourth print head 51 as maintenance targets at the same time. Adjust the above selections so that Similarly, the control device 90 prevents the first print head 51 and the third print head 51 from being subject to maintenance at the same time, and the second print head 51 and the fourth print head 51 to be subject to maintenance at the same time. Adjust the above choices to not.

According to the above-described first or second maintenance process, the supply of the tablets T is not stopped for maintenance, and the tablets T are sequentially supplied to each of the transport belts 21 and each of the print heads 51 is used. Printing is executed. As a result, the print stop time due to the maintenance of the print head 51 is eliminated, so that it is possible to prevent the productivity from decreasing due to the print stop due to the maintenance.

In addition, in the second maintenance step, the maintenance can be performed according to the actual frequency of use of the print heads 51 by counting the number of times each print head 51 is driven. As a result, unnecessary maintenance can be omitted, productivity can be improved, and stable printing can be performed even on the tablets T that are randomly transported. In addition to the number of times the drive elements are driven for each print head 51, for example, the maintenance target can be selected from each print head 51 according to the number of prints for each print head 51 (the number of printed tablets T for each print head 51). It is also possible to select.

As described above, according to the second embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, since printing is continued by any of the print heads 51, it is possible to eliminate a printing stop time associated with maintenance and to prevent productivity from being reduced due to the print suspension associated with maintenance.

(Third Embodiment)
A third embodiment will be described with reference to FIG. In the third embodiment, differences from the first embodiment (number of print heads and maintenance process) will be described, and other description will be omitted.

As shown in FIG. 5, in the third embodiment, four print heads 51 are provided, and there are four print positions. Here, for simplification of description, the four print heads 51 are distinguished as a first print head 51, a second print head 51, a third print head 51, and a fourth print head 51, and in FIG. The four print heads 51 are designated by the reference numerals 1, 2, 3 and 4. Further, the two conveyor belts 21 are distinguished as the first conveyor belt 21 and the second conveyor belt 21, and reference numerals 1 and 2 are written on the two conveyor belts 21 in FIG.

The first print head 51 and the second print head 51 are arranged in the Y direction. The third print head 51 and the fourth print head 51 are also arranged in the Y direction. The first print head 51 and the second print head 51 arranged in the Y direction are moved together in the Y direction by the moving mechanism 72a. Similarly, the third print head 51 and the fourth print head 51 arranged in the Y direction are moved together in the Y direction by the moving mechanism 72b. The first print head 51 and the second print head 51 are in a group that shares one maintenance position, and the third print head 51 and the fourth print head 51 are in a group that share one maintenance position. ..

In the first print head 51 and the second print head 51, when the first print head 51 is in the print position of the first conveyor belt 21, the second print head 51 is in the maintenance position. When the first print head 51 is in the maintenance position, the second print head 51 is in the print position of the second conveyor belt 21. Similarly, also in the third print head 51 and the fourth print head 51, when the third print head 51 is in the maintenance position, the fourth print head 51 is in the print position of the second conveyor belt 21. Exists. When the third print head 51 is in the print position of the first conveyor belt 21, the fourth print head 51 is in the maintenance position.

In the maintenance process, the first print head 51 and the fourth print head 51 stop printing when a predetermined time elapses after the first print head 51 and the fourth print head 51 start printing, and the printing is performed respectively. Move from position to maintenance position and start maintenance. Along with this movement, the second print head 51 moves from the maintenance position to the print position of the second conveyor belt 21, and the third print head 51 moves from the maintenance position to the print position of the first conveyor belt 21. And start printing. When the maintenance is completed, the first print head 51 and the fourth print head 51 each stand by at the maintenance position.

After that, when a predetermined time elapses after the second print head 51 and the third print head 51 start printing, the second print head 51 and the third print head 51 stop printing, and from the print positions, respectively. Move to the maintenance position and start maintenance. With this movement, the first print head 51 moves from the maintenance position to the print position of the first conveyor belt 21, and the fourth print head 51 moves from the maintenance position to the print position of the second conveyor belt 21. And start printing. Such processing is repeated.

The maintenance is executed every predetermined time, but the predetermined time in the maintenance process is set to a time at which the print head 51 waiting at the printing position can print as it is. For example, while the first print head 51 is printing, the second print head 51 is waiting at the maintenance position. If this waiting time becomes long, the ink in each nozzle 51a of the second print head 51 may dry, and ejection failure may occur. Therefore, the above-mentioned predetermined time is experimentally or theoretically set in advance so that the ejection failure does not occur. However, the predetermined time does not necessarily have to be set as described above. For example, when the print head 51 waiting at the maintenance position performs printing, dummy ejection is performed before moving to the printing position, and then printing is performed. It is also possible to move to the position and start printing.

According to this maintenance step, the supply of the tablets T is not stopped for maintenance, and the tablets T are sequentially supplied to the respective conveyor belts 21 and printed by any of the print heads 51. As a result, the print stop time due to the maintenance of the print head 51 is eliminated, so that it is possible to prevent the productivity from decreasing due to the print stop due to the maintenance.

The moving speed of each print head 51 is set so that the unprinted tablets T are not generated during the movement of each print head 51. However, when the distance between the tablets T adjacent to each other in the X direction is very short, the tablets T that are not printed may occur during the movement of the print heads 51, so the supply of the tablets T is stopped for a predetermined time (several seconds). Then, the distance between the tablets T adjacent in the X direction is increased. As a result, it is possible to prevent the generation of tablets T that are not printed during the movement of each print head 51.

As described above, according to the third embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, since printing is continued by any of the print heads 51, it is possible to eliminate a printing stop time associated with maintenance and to prevent productivity from being reduced due to the print suspension associated with maintenance.

(Fourth Embodiment)
A fourth embodiment will be described with reference to FIG. In the fourth embodiment, the difference (maintenance device) from the first embodiment will be described, and the other description will be omitted.

As shown in FIG. 6, the maintenance device 70 according to the fourth embodiment includes a discharge pipe 73 and a storage part 74 in addition to the liquid receiving part 71 and the like. The bottom surface of the liquid receiving portion 71 is inclined so as to gradually lower toward one of the two end portions in the Y direction on the bottom surface. A discharge port 71a is formed at one end thereof, and one end of a discharge pipe 73 is connected to this discharge port 71a. The other end of the discharge pipe 73 is connected to the storage section 74. The ink ejected from each nozzle 51a of the print head 51 located at the maintenance position hits the bottom surface of the liquid receiving portion 71, moves along the bottom surface, and flows into the discharge pipe 73 from the discharge port 71a. The storage unit 74 stores the ink flowing out from the discharge pipe 73. The bottom surface of the liquid receiving portion 71 may be inclined in any direction as long as it is inclined toward the place where the discharge port 71a is formed. Moreover, the numbers of the discharge ports 71a, the discharge pipes 73, and the storage portions 74 are not particularly limited.

A filter 73a is provided inside the aforementioned discharge pipe 73. The filter 73a removes foreign matter such as powder of the tablet T from the ink flowing through the discharge pipe 73. A sensor (detection unit) 75 that detects clogging of the filter 73a is provided. An alarm (not shown) is connected to the control device 90. The notification device issues a warning urging maintenance of the filter 73a according to the detection result of the sensor 75. As the notification device, for example, a lamp, a buzzer, a display device, or the like can be used. It should be noted that such a filter 73a and an annunciator may be installed as necessary, or may be omitted.

In the maintenance process, the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position hits the bottom surface of the liquid receiving portion 71 and flows toward the discharge port 71a along the bottom surface according to the inclination of the bottom surface. The ink flows into the discharge pipe 73 from the discharge port 71 a, flows into the storage portion 74 via the discharge pipe 73, and is stored by the storage portion 74. In the maintenance process by pressure feeding, the amount of ink ejected from each nozzle 51a of the print head 51 is larger than that in the maintenance process by dummy ejection. When a large amount of ink collects on the bottom surface of the liquid receiving portion 71, the tendency of liquid splashing at the time of the next maintenance increases. Therefore, by providing the discharge pipe 73 and the storage portion 74, it is possible to suppress the accumulation of a large amount of ink on the bottom surface of the liquid receiving portion 71, and it is possible to suppress the contamination of the print head 51 and the like due to the liquid splash. ..

As described above, according to the fourth embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, by providing the discharge pipe 73 and the storage portion 74, it is possible to suppress the accumulation of a large amount of ink on the bottom surface of the liquid receiving portion 71, and the surface of the print head 51 or the transport belt 21 due to liquid splash (for example, It is possible to suppress contamination of the surface of the belt on which the tablets T are placed) and the tablets T during transportation.

(Fifth Embodiment)
A fifth embodiment will be described with reference to FIG. In the fifth embodiment, the difference (maintenance device) from the first embodiment will be described, and the other description will be omitted.

As shown in FIG. 7, the liquid receiving portion 71 of the maintenance device 70 according to the fifth embodiment has a convex portion 71b on its bottom surface. For example, the convex portion 71b has a mountain shape whose top extends in the X direction, and is formed so that ink ejected from each nozzle 51a of the print head 51 located at the maintenance position hits each inclined surface of the convex portion 71b. Has been done. Therefore, it is desirable that the maximum length of the convex portion 71b in the Y direction be equal to or larger than the ink landing width of the bottom surface of the liquid receiving portion 71. The ink landing width is the width on the bottom surface from which the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position is landed. In addition, the shape of the convex portion 71b may be a mountain shape having a single peak, or may be a V shape or a funnel shape.

In the maintenance process, the ink ejected from each nozzle 51a of the print head 51 at the maintenance position hits each inclined surface of the convex portion 71b of the liquid receiving portion 71, flows along the inclined surface, and the Y direction on the bottom surface. Move toward both ends of. Here, if the bottom surface of the liquid receiving portion 71 is flat, the ink collects in the landing area on the bottom surface where the ink hits, so that the tendency of liquid splashing at the time of the next maintenance or the like increases. Therefore, by providing the convex portion 71b on the bottom surface of the liquid receiving portion 71, the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position flows along each inclined surface of the convex portion 71b, and the liquid receiving portion 71b is formed. It will accumulate outside the landing area on the bottom surface of the portion 71. As a result, it is possible to prevent ink from accumulating in the landing area on the bottom surface of the liquid receiving portion 71, and it is possible to suppress contamination of the print head 51 and the like due to liquid splashing. Further, when the bottom surface is flat, the liquid splashing direction becomes random, but the liquid splashing direction can be adjusted to some extent by adjusting the angle of each inclined surface.

As described above, according to the fifth embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, by providing the convex portion 71b on the bottom surface of the liquid receiving portion 71, it is possible to prevent ink from accumulating in the landing area of the bottom surface of the liquid receiving portion 71, so that the print head 51 and the transport belt due to splashing of the liquid. It is possible to suppress contamination of the surface of 21 (for example, the surface of the belt on which the tablet T is placed), the tablet T during transportation, and the like.

(Sixth Embodiment)
A sixth embodiment will be described with reference to FIG. In the sixth embodiment, the difference (maintenance device) from the first embodiment will be described, and the other description will be omitted.

As shown in FIG. 8, the maintenance device 70 according to the sixth embodiment includes a plurality of suction tubes 76 and suction portions 77 in addition to the liquid receiving portion 71 and the like. Two suction ports 71c are formed on the bottom surface of the liquid receiving portion 71, and these suction ports 71c are arranged in the X direction. Each suction port 71c is formed in a rectangular slit longer than the length of the nozzle row. One end of each suction pipe 76 is individually connected to these suction ports 71c. The other end of each suction pipe 76 is connected to the suction unit 77. The suction unit 77 is, for example, a suction pump or the like and generates a suction force. The suction unit 77 includes a liquid collection unit such as a liquid trap, a filter (neither is shown), and the like. The suction unit 77 is electrically connected to the control device 90, and its drive is controlled by the control device 90.

Here, each suction port 71c is provided corresponding to each maintenance position located above the liquid receiving portion 71, and is provided on the bottom surface of the liquid receiving portion 71 so as to face the print head 51 existing at the maintenance position. Each is formed. The suction ports 71c are formed in such a size that ink ejected from the nozzles 51a of the print head 51 located at the maintenance position passes through and does not bounce. Therefore, the length of the suction port 71c in the Y direction is equal to or larger than the ink landing width of the bottom surface of the liquid receiving portion 71. The ink landing width is the width on the bottom surface from which the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position is landed.

In the maintenance process, the suction unit 77 is driven by the control device 90, and air is sucked from the two suction ports 71c on the bottom surface of the liquid receiving unit 71. In this state, the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position passes through the suction port 71c of the liquid receiving portion 71 and is sucked by the suction pipe 76. This ink flows through the suction pipe 76 and is recovered by the liquid recovery unit of the suction unit 77. The suction unit 77 is driven during maintenance, and is not driven during normal times other than during maintenance. However, it is also possible to share the suction device of the transfer device 20 as the suction part 77. In this case, since the suction device is constantly driven, air is constantly sucked from each suction port 71c.

Here, when the ink hits the bottom surface of the liquid receiving portion 71, the ink may splash and a mist may be generated due to the rising of the droplet. Therefore, by forming the suction port 71c on the bottom surface of the liquid receiving portion 71 so as to face the print head 51 existing at the maintenance position, it is possible to suppress the rising of the droplets during maintenance, that is, the generation of mist. Become. As a result, it is possible to prevent the print head 51 and the transport belt 21 around the liquid receiving portion 71 from being contaminated by the mist.

As described above, according to the sixth embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, by forming the suction port 71c on the bottom surface of the liquid receiving portion 71 so as to face the print head 51 existing at the maintenance position, it is possible to suppress the rising of the droplets during maintenance, that is, the generation of mist. Therefore, it is possible to prevent the print head 51 and the transport belt 21 around the liquid receiving portion 71 from being contaminated by the mist.

(Seventh embodiment)
The seventh embodiment will be described with reference to FIG. In the seventh embodiment, the difference (maintenance device) from the sixth embodiment will be described, and the other description will be omitted.

As shown in FIG. 9, in the seventh embodiment, two suction ports 71c are formed on the bottom surface of the liquid receiving portion 71, and the suction pipes 76 are individually connected to the suction ports 71c. The two suction ports 71c are formed at both ends of the bottom surface of the liquid receiving portion 71 in the Y direction. Further, these suction ports 71c are formed so as to extend in the X direction over the bottom surface of the liquid receiving portion 71. The bottom surface of the liquid receiving portion 71 is inclined so as to gradually decrease toward the center. The two suction pipes 76 suck the mist generated in the liquid receiving portion 71 through the suction ports 71c, respectively. As described above, the mist is generated when the ink ejected from the print head 51 located at the maintenance position hits the bottom surface of the liquid receiving portion 71 and splashes, and the droplets rise up.

In the maintenance process, the suction unit 77 is driven by the control device 90, and air is sucked from the two suction ports 71c of the liquid receiving unit 71. In this state, the ink ejected from each nozzle 51a of the print head 51 located at the maintenance position hits the bottom surface of the liquid receiving portion 71, flows along the inclination of the bottom surface, and gradually accumulates at the center of the bottom surface. At this time, even if mist is generated due to the rising of the droplets, the mist is sucked together with air by the two suction pipes 76. As a result, the mist can be removed during maintenance, so that it is possible to suppress the contamination of the print head 51 and the transport belt 21 around the liquid receiving portion 71 due to the mist.

An exhaust pipe (not shown) can be connected to the center of the bottom surface. In this case, the ink that has moved to the center of the bottom surface flows into the discharge pipe and is discharged through the discharge pipe. As a result, it is possible to prevent ink from accumulating in the landing area on the bottom surface of the liquid receiving portion 71, and it is possible to suppress contamination of the print head 51 due to liquid splashing.

As described above, according to the seventh embodiment, it is possible to obtain the same effects as those of the first embodiment. Further, by forming the suction port 71c at any position on the bottom surface of the liquid receiving portion 71, it is possible to remove the mist generated by the rising of the droplets during maintenance. Contamination of the conveyor belt 21 and the like around the receiving portion 71 can be suppressed.

(Eighth Embodiment)
The eighth embodiment will be described with reference to FIG. In the eighth embodiment, the difference (maintenance device) from the seventh embodiment will be described, and the other description will be omitted.

As shown in FIG. 10, in the eighth embodiment, two gas spraying portions 78 are provided. These gas spraying portions 78 are provided at a position higher than the upper end of the print head 51 so as not to hinder the movement of the print head 51. Further, each gas spraying section 78 is arranged so as to face each suction port 71 c of the liquid receiving section 71. These gas spraying portions 78 are formed so as to extend in the X direction. A slit-shaped blowout hole (not shown) extending in the X direction is formed in the lower portion of each gas blowing portion 78. Therefore, the gas blowing section 78 blows out gas (for example, air or nitrogen) downward to form a curtain of gas. Each gas spraying unit 78 is electrically connected to the control device 90, and its drive is controlled by the control device 90.

In the maintenance process, each gas spraying section 78 is driven by the controller 90, air (an example of gas) is blown out from the gas spraying sections 78, and is sucked from the two suction ports 71c of the liquid receiving section 71. As a result, airflow curtains, that is, air curtains (an example of gas curtains) are formed on both sides of the print head 51. Similar to the seventh embodiment, when ink hits the bottom surface of the liquid receiving portion 71, a mist may be generated due to the rising of the droplets. The mist along with the flow of the air curtain is accompanied by two suction pipes together with air. Aspirated by 76. Furthermore, even if a large amount of mist is generated, the air curtain can prevent the mist from flowing out of the opening in the upper part of the liquid receiving portion 71 to the transport belt 21 side. In this way, it is possible to remove mist at the time of maintenance and to suppress the outflow of mist, so that it is possible to suppress contamination of the print head 51 and the transport belt 21 around the liquid receiving portion 71 due to mist. Further, by sucking the gas from below the gas blowing portion 78 (downward suction), it is possible to prevent the width of the air curtain from expanding, and it is possible to prevent the printing near the air curtain from being affected. ..

In addition, as shown in FIG. 11, in the modified example, a suction head 79 is provided for each gas spraying section 78 in addition to the two gas spraying sections 78 described above. The gas spraying unit 78 blows gas toward the space between the transport belt 21 and the liquid receiving unit 71 in parallel with the transport direction A1 of the tablet T so as to form an air curtain between the transport belt 21 and the liquid receiving unit 71. Blow out. The suction head 79 is formed in a gutter shape whose upper surface is open and extends in the X direction, and has a suction port 79a extending in the X direction. The suction head 79 is positioned below the gas spraying section 78 and lower than the liquid receiving section 71, and the suction port 79 a is provided so as to face the gas spraying section 78. The suction head 79 is connected to the suction unit 77 via a suction pipe (not shown). The suction head 79 sucks the gas blown out from the gas blowing section 78 and passing between the transport belt 21 and the liquid receiving section 71. As a result, the air curtain is formed outside the liquid receiving portion 71 and is formed along the extending direction of the transport belt 21, that is, the transport direction A1 (for example, parallel to the transport belt 21). The suction mechanism using the suction head 79 or the suction tube 76 described above is not essential, and only the air curtain may be formed.

As described above, according to the eighth embodiment, it is possible to obtain the same operational effect as the first embodiment. Further, by providing the gas spraying section 78, even if a large amount of mist is generated, the mist flows out from the upper opening of the liquid receiving section 71 to the conveyor belt 21 side by an air curtain (an example of an airflow curtain). Since it is possible to suppress the contamination, it is possible to reliably suppress the contamination of the transport belt 21 and the like around the liquid receiving portion 71 due to the mist.

(Other embodiments)
Although the hopper 11 and the shooter 12 are used as the supply device 10 in each of the above-described embodiments, the supply device 10 is not limited to this, and various supply mechanisms can be used. For example, it is possible to supply a tablet T to the carrier device 20 by providing a delivery mechanism that sucks and conveys the tablet T on the lower surface. In this case, in order to stop the supply of the tablets T to the transport device 20, the suction by the delivery mechanism may be stopped.

In addition, in each of the above-described embodiments, the tablets T are conveyed in two rows by the conveyor belt 21. However, the present invention is not limited to this, and may be in one row, three rows, or four or more rows. The number is not particularly limited. It is possible to print on two or more rows of tablets T by one print head 51, but the present invention is not limited to this, and the print heads 51 may be provided for each row, for example.

Further, in each of the above-described embodiments, the case where only two conveyor belts 21 are provided has been illustrated, but the present invention is not limited to this, and two or more conveyor belts 21 may be provided. For example, as shown in FIG. 12, when three transport belts 21 are provided, it is possible to provide the liquid receiving portions 71 in all of the individual transport belts 21. That is, the number of transport paths for the tablets T is not limited to two (two rows) but may be more than two, and the liquid receiving portion 71 is provided between the respective transport paths. Further, the transport path is not limited to the transport belt 21, and may be, for example, one using a cylindrical drum, tray, pallet or the like.

Further, in each of the above-described embodiments, the carrier device 20 exemplifies a carrier device that holds and transports the tablet T by suction, but the present invention is not limited to this, and various carrier mechanisms can be used. .. Further, as the holding mechanism for sucking and holding the tablet T, the holding of the tablet T by the slit-shaped suction port 21a extending in the carrying direction A1 is illustrated, but the holding mechanism is not limited to this, and for example, in the carrying direction A1. The tablets T may be held by a plurality of circular suction ports arranged side by side.

Further, in each of the above-described embodiments, the printing timing is set based on the detection device 30, but the present invention is not limited to this. For example, the printing timing may be set based on the imaging device 40. ..

Further, in each of the above-described embodiments, as the inkjet print head 51, a print head in which the nozzles 51a are arranged in a line is illustrated, but the invention is not limited to this, and for example, a print head in which the nozzles 51a are arranged in a plurality of lines is used. You may use it.

Further, in each of the above-described embodiments, the liquid receiving portion 71 is fixedly provided, but the present invention is not limited to this, and the liquid receiving portion 71 may be moved by a moving mechanism, for example. For example, as the moving mechanism, a vertical moving mechanism that moves the liquid receiving portion 71 in the vertical direction can be provided. In this case, at the time of maintenance, it is possible to adjust the separation distance between the print head 51 existing at the maintenance position and the liquid receiving portion 71.

Further, in each of the above-described embodiments, the liquid receiving portion 51 is provided as the maintenance portion that performs maintenance, but the present invention is not limited to this, and, for example, in addition to the liquid receiving portion 51, or Instead of the receiving portion 51, it is possible to provide a wiping portion for wiping off excess ink adhering to the nozzle surface of the print head 51. Further, another maintenance mechanism can be provided as the maintenance unit.

Here, the above-mentioned tablets may include tablets used for medicine, food and drink, washing, industrial use or aromatization. Examples of tablets include a plain tablet, a sugar-coated tablet, a film-coated tablet, an enteric-coated tablet, a gelatin-coated tablet, a multilayer tablet, and a dry-coated tablet. Furthermore, various capsule tablets such as hard capsules and soft capsules can be included in the tablets. The shape of the tablet includes various shapes such as a disk shape, a lens shape, a triangle shape, and an elliptical shape.

When the tablet to be printed is for medicine or food and drink, edible ink is suitable as the ink to be used. Specifically, as edible pigments, amaranth, erythrosine, new coccin (above, red), tartrazine, sunset yellow FCF, β-carotene, crocin (above, yellow), brilliant blue FCF, indigo carmine (above, blue) ) Or the like, and these are dispersed or dissolved in a vehicle, and if necessary, a dye dispersant (surfactant) may be added thereto. As the edible ink, any of synthetic dye ink, natural dye ink, dye ink, and pigment ink may be used.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and an equivalent range thereof.

DESCRIPTION OF SYMBOLS 1 Tablet printing device 21 Conveyor belt 51 Printing head 51a Nozzle 71 Liquid receiving part 71b Convex part 71c Suction port 72 Moving device 78 Gas spraying part T Tablet

Claims (7)

At least two transport paths through which tablets are transported,
A maintenance unit provided between the two transfer paths for performing maintenance,
An inkjet print head that is provided above the transport path for each of the transport paths and around the maintenance unit, and that ejects liquid from a nozzle;
A moving device that individually moves each print head to a print position above the transport path for each print head and a maintenance position above the maintenance unit for each print head;
A tablet printing apparatus comprising: At least two transport paths through which tablets are transported,
A maintenance unit provided between the two transfer paths for performing maintenance,
An inkjet print head that is provided above the transport path for each of the transport paths and around the maintenance unit, and that ejects liquid from a nozzle;
A moving device that moves each print head to a print position above the transport path for each print head and a plurality of maintenance positions above the maintenance unit;
Equipped with
The print heads are arranged in the transport direction of the tablets in two or more for each transport path,
The maintenance position is provided for each set of the print heads arranged in a direction intersecting the transport direction,
The tablet printing apparatus, wherein the moving device moves each of the print heads individually so as to share the maintenance position for each set of the print heads. At least two transport paths through which tablets are transported,
A maintenance unit provided between the two transfer paths for performing maintenance,
An inkjet print head that is provided above the transport path for each of the transport paths and around the maintenance unit, and that ejects liquid from a nozzle;
A moving device that moves each print head to a print position above the transport path for each print head and a plurality of maintenance positions above the maintenance unit;
Equipped with
The print heads are arranged in a direction intersecting with the transportation direction of the tablets for each of the transportation paths.
The maintenance position is provided for each set of the print heads arranged in a direction intersecting the transport direction,
The tablet printing apparatus, wherein the moving device moves each of the print heads for each group of the print heads so as to share the maintenance position for each group of the print heads. 3. The moving device individually moves each of the print heads such that at least one of the two or more print heads is present at the print position for each of the transport paths. Tablet printing device. The moving device moves each of the print heads for each set of print heads so that at least one of the two or more print heads is at the print position and the other one is at the maintenance position. The tablet printing apparatus according to claim 3, wherein the tablet printing apparatus is a tablet printing apparatus. The tablet printing apparatus according to any one of claims 1 to 5, further comprising: a gas blowing unit that blows a gas between the printing position and the maintenance position, the gas blowing unit being in parallel with a transportation direction of the tablet. The tablet printing apparatus according to claim 6, further comprising: a suction port that is disposed so as to face the gas spraying unit and that suctions the gas blown out by the gas spraying unit.

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