JP2021126524A - Tablet printing device - Google Patents

Abstract

To provide a tablet printing device capable of suppressing deterioration in productivity attributed to printing stop accompanying maintenance of a printing head.SOLUTION: A tablet printing device 1 includes: two conveyance belts 21 that function as at least two conveyance routes where tablets are conveyed; a liquid receiving part 71 provided between the two conveyance belts 21 that function as a maintenance part for executing maintenance; a printing head 51 of an inkjet system provided above the conveyance belt 21 and in the periphery of the liquid receiving part 71 for each conveyance belt 21, which discharges liquid from a nozzle; and a moving device 72 for individually moving each printing head 51 to a printing position above the conveyance belt 21 for each printing head 51 and a maintenance position above the liquid receiving part 71 for each printing head 51.SELECTED DRAWING: Figure 3

Description

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

In order to print identification information such as characters and symbols on tablets, a technique of printing using an inkjet printing head is known. In a tablet printing apparatus using this technique, a plurality of tablets are conveyed in a row by a conveyor, and ink (for example, possible) is directed from a nozzle of an inkjet printing head arranged above the conveyor to a tablet passing below the printing head. Eating 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 printing head, they cause ejection failure. Further, when an ink that is easily dried is used as the printing ink, the ink in the nozzle may be thickened or solid matter may be deposited, which causes ejection failure. The occurrence of such ejection defects leads to deterioration of print quality.

Therefore, maintenance (dummy ejection and pressure feeding) for ejecting ink from the nozzles of the print head is periodically performed, and the print head is maintained in a normal state. Generally, it is necessary to stop the tablet transfer every time the print head needs maintenance. During this suspension period, printing on the tablets is interrupted, which causes a problem that productivity is lowered. It is conceivable to improve the productivity by transporting the tablets in multiple rows, but there are still the same problems.

Japanese Unexamined Patent Publication No. 7-081050

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

The tablet printing apparatus according to the embodiment of the present invention includes a maintenance unit provided between at least two transport paths for transporting tablets and two transport paths for performing maintenance, and a transport route for each transport route. Each print is made on an inkjet print head that is provided around the maintenance unit and is located above the maintenance unit and discharges liquid from the nozzle, and at the print position above the transport path for each print head and at the maintenance position above the maintenance unit for each print head. It is provided with a moving device for moving the heads individually.

The tablet printing apparatus according to the embodiment of the present invention includes a maintenance unit provided between at least two transport paths for transporting tablets and two transport paths for performing maintenance, and a transport route for each transport route. An inkjet print head that is provided above the maintenance unit and discharges liquid from a nozzle, and each print head at a print position above the transport path for each print head and at a plurality of maintenance positions above the maintenance unit. It is equipped with a moving device for moving. Two or more print heads are arranged in the transport direction of tablets for each transport path, maintenance positions are provided for each set of print heads lined up in a direction intersecting the transport direction, and the moving device is a print head. Each print head is moved individually so that the maintenance position is shared by each set.

The tablet printing apparatus according to the embodiment of the present invention includes a maintenance unit provided between at least two transport paths for transporting tablets and two transport paths for performing maintenance, and a transport route for each transport route. An inkjet print head that is provided above the maintenance unit and discharges liquid from a nozzle, and each print head at a print position above the transport path for each print head and at a plurality of maintenance positions above the maintenance unit. It is equipped with a moving device for moving. The print heads are arranged in a direction intersecting the tablet transport direction for each transport path, maintenance positions are provided for each pair of two or more print heads, and the moving device is a print head. Each print head is moved for each set of print heads so that the maintenance position is shared by each set of print heads.

According to the embodiment of the present invention, it is possible to suppress a decrease in productivity due to printing stoppage due to maintenance of the print head.

It is a figure which shows the schematic structure of the tablet printing apparatus which concerns on 1st Embodiment. It is a top view which shows a part of the tablet printing apparatus which concerns on 1st Embodiment. It is an enlarged plan view which shows a part of the tablet printing apparatus which concerns on 1st Embodiment. It is an enlarged plan view which shows a part of the tablet printing apparatus which concerns on 2nd Embodiment. It is an enlarged plan view which shows a part of the tablet printing apparatus which concerns on 3rd Embodiment. It is a figure which shows the schematic structure of the maintenance apparatus which concerns on 4th Embodiment. It is a figure which shows the schematic structure of the maintenance apparatus which concerns on 5th Embodiment. It is a figure which shows the schematic structure of the maintenance apparatus which concerns on 6th Embodiment. It is a figure which shows the schematic structure of the maintenance apparatus which concerns on 7th Embodiment. It is a figure which shows the schematic structure of the maintenance apparatus which concerns on 8th Embodiment. It is a figure which shows the schematic structure of the modification of the maintenance apparatus which concerns on 8th Embodiment. It is a figure which shows the schematic structure of the modification of the maintenance apparatus which concerns on 2nd Embodiment.

(First Embodiment)
The 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 device 1 according to the first embodiment includes a supply device 10, a transfer device 20, a detection device 30, an image pickup 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 are provided.

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 contained tablets T to the shooter 12. The shooter 12 arranges the supplied tablets T in a plurality of rows and supplies them to the transfer 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 transport belts 21 is formed in an endless shape, and is bridged to the drive pulley 22 and the driven pulley 23 in parallel with each other. The drive pulley 22 and the driven pulley 23 are rotatably provided about 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 the drive thereof 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 transport belt 21 based on the detection signal. The transport device 20 has two transport paths due to the two transport belts 21.

The 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 tablet T on the transport belt 21 is transferred to the tablet T on the transport belt 21 by the arrow A1 (convey direction) in FIGS. 1 and 2. Transport to A1). Each of the transport belts 21 is formed with straight slit-shaped suction ports 21a (see FIG. 2) in two rows along the transport direction A1. The two suction ports 21a are connected to a suction device (neither 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 on the suction port 21a is held on the transport 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 detection units 31 are provided above the transport belt 21 for each transport belt 21. These detection units 31 are located 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 the horizontal plane (for example, in a direction orthogonal to each other). Has been done. Each detection unit 31 detects the tablet T on the transport belt 21 by transmitting and receiving laser light. These detection units 31 are electrically connected to the control device 90 and transmit a detection signal to the control device 90. As the detection unit 31, for example, various laser sensors (laser displacement meters) such as a reflection type laser sensor can be used. Further, as the beam shape of the laser beam, various shapes such as spots and lines can be used.

The image pickup apparatus 40 includes a plurality of image pickup units 41 (see FIG. 2). Two imaging units 41 are provided above the transport belt 21 for each transport belt 21. These imaging units 41 are located 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, in a direction orthogonal to each other). Has been done. The imaging field of view of the imaging unit 41 is such that only one tablet T transported by the transport belt 21 enters the imaging field of view, and the tablet T on the upstream or downstream side of the transport direction A1 and the tablet T in the adjacent row do not enter. It is set to. The image pickup unit 41 takes 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 image pickup unit 41, for example, various cameras having an image pickup device such as a CCD (charge-coupled device) or a CMOS (complementary metal oxide semiconductor) can be used. Each image pickup 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. Lighting for imaging is also provided as needed.

The printing device 50 includes a plurality of inkjet printing heads 51. Each print head 51 is provided above the transport belt 21 for each transport belt 21, and is positioned downstream of the image pickup apparatus 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 transport direction A1 in the print head 51) 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 inks (an example of a liquid) are individually ejected from the nozzles 51a. The print head 51 is provided so that the nozzle alignment directions in which the nozzles 51a are lined up intersect with the transport direction A1 in the horizontal plane (for example, so as to be orthogonal to each other). As the print head 51, for example, various inkjet print heads having a driving element such as a piezoelectric element, a heat generating element, or a magnetostrictive element can be used. The print head 51 is electrically connected to the control device 90, and its drive is controlled by the control device 90.

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

As shown in FIG. 3, the maintenance device 70 includes a liquid receiving unit 71 and a moving device 72. In addition, in FIG. 1 and FIG. 2, the moving device 72 is omitted for the sake of simplification of the figure.

The liquid receiving portion 71 is formed in a box shape having an open upper portion, for example, and is provided between two adjacent transport belts 21. The liquid receiving unit 71 receives the ink discharged from the nozzles 51a of the printing head 51 facing each other during 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 (approximately the same as the width of one head, and at least the width of two heads). Is also short). Each print head 51 is present around the liquid receiving portion 71, and these printing 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 transport 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 transport belts 21 may be removed when maintaining the two transport belts 21, but the transport belts 21 may be removed only 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 transport direction A1 from the image pickup apparatus 40, and are provided above each transport belt 21 and the liquid receiving portion 71 so as to be along the direction orthogonal to the transport direction A1 on the 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 described above. Each of the moving mechanisms 72a and 72b movably supports the print head 51 in a direction orthogonal to the transport direction A1, a maintenance position where the print head 51 faces the liquid receiving portion 71, and a printing position where the print head 51 faces the transport belt 21. The print head 51 is moved to (coating 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 for the print head 51 to eject ink toward the liquid receiving portion 71. This maintenance position is provided for each print head 51, and there are two above the liquid receiving portion 71. These maintenance positions are lined up along the transport direction A1. The printing position is a position for ejecting ink toward the tablet T transported by the transport belt 21. This printing position is provided for each print head 51, and exists two above the first transport belt 21 and above the second transport belt 21. These printing positions are deviated from each other by a predetermined distance in the transport direction A1. That is, in FIG. 3, the position of the print head 51 shown by the solid line on the transport belt 21 is the print position, and the position of the print head 51 shown 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 image pickup device 40, processes each image using a known image processing technique, and shifts the positions of the tablet T in the X direction, the Y direction, and the θ direction (rotation direction). Is detected (see FIG. 3). Here, the misalignment in the X direction and the Y direction is the misalignment of the tablet T with respect to the center of the imaging field of view, and it is detected how much the tablet T is misaligned 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.

Further, the positional deviation in the θ direction is a rotational deviation of the tablet T in the horizontal plane. This misalignment in the θ direction occurs when the tablet T has a directional shape, such as when the tablet T is provided with a dividing line or when the tablet T is molded into an oval shape, an oval shape, a quadrangle, or the like. Detected. For example, when a dividing line is formed on the tablet T, the state in which the direction of the dividing line is parallel to the Y direction is 0 degree, and the θ deviation is obtained in 1 degree units in the range of 0 degree to 179 degrees. do. Further, when the shape of the tablet T is not line-symmetrical with respect to the dividing line, the θ deviation may be obtained in the range of 0 degrees to 359 degrees. When the tablet T has a non-directional form, it is not necessary to detect the θ deviation.

The image processing device 80 transmits the position shift information of each of the detected tablets 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 misalignment information, the identification information of each imaging unit 41 is added to the misalignment information and transmitted. As a result, the control device 90 recognizes which row of the tablet T transported in four rows by the two transport belts 21 is the misaligned information transmitted. can do.

The control device 90 includes a microprocessor that centrally controls each unit and a storage unit (none of which is shown) that stores processing information, various programs, and the like. The control device 90 controls the supply device 10, the transfer device 20, the image pickup device 40, and the printing device 50 based on various information and various programs. Further, the control device 90 receives a detection signal transmitted from the detection device 30 and the position detector 24a, an image transmitted from the image pickup device 40, and the like.

Further, the control device 90 detected the misalignment in the X, Y and θ directions based on the misalignment information in the X, Y and θ directions 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 composed of print patterns such as characters and symbols to be printed on the tablet T, and data such as printing positions of those characters and symbols on the tablet T, and each transport belt 21. The movement speed information of is stored.

For example, the control device 90 determines the range of use of the nozzle 51a used for the current printing in the print head 51 based on the positional deviation in the Y direction. As an example, it is assumed that among the plurality of nozzles 51a included in the print head 51, five nozzles 51a are used for applying the tablet T, and the amount of misalignment of the tablet T in the Y direction is one pitch of the arrangement interval of the nozzles 51a. If this is the case, the printing conditions are set so as to use the five nozzles 51a in which the usage range of the nozzles 51a is shifted by one pitch in the misalignment direction of the tablet T.

Further, the control device 90 determines the timing to start printing on the tablet T based on the misalignment in the X direction. For example, when the tablet T is displaced by a distance ΔX to the upstream side of the transport direction A1, the time required for the transport belt 21 to move by a distance ΔX as compared with the case where the tablet T is not displaced in the X direction. Set the print conditions so that printing starts at the timing delayed by.

Further, the control device 90 sets the printing conditions rotated according to the rotational deviation of the tablet T based on the positional deviation in the θ direction. For example, 180 types of print data in which the orientation of print patterns such as characters and symbols are rotated by 1 degree in the range of 0 degrees to 179 degrees are registered in the storage unit of the control device 90, and the print data of the print data From the list, select print data with an angle that matches the detected positional deviation in the θ direction, and set the print conditions.

(Printing process)
Next, the printing process (printing process) performed by the tablet printing apparatus 1 described above 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. Then, when the tablet printing device 1 is driven, each of the transport belts 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. In a state where each transport belt 21 is rotating, tablets T are sequentially supplied onto each transport belt 21 from the supply device 10 at random rather than at regular intervals. The tablets T are transported in two rows for each transport belt 21 at a predetermined moving speed.

Each tablet T on each transport belt 21 is detected by each detection unit 31 for each transport belt 21, and each detection signal is input to the control device 90 as a trigger signal from each detection unit 31. After that, each tablet T on each transport belt 21 is imaged by each imaging unit 41 for each transport belt 21. The upper surface of the tablet T is imaged by the image pickup unit 41 at the timing based on the above-mentioned trigger signal, that is, at the timing when the tablet T reaches the lower part of the image pickup unit 41, and the captured image is transmitted to the image processing device 80. Based on the individual images transmitted from each image pickup unit 41, the position shift information of the tablet T (for example, the position shift 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. It is transmitted to 90. Based on the misalignment information of the tablet T, the printing conditions for the tablet T are set by the control device 90.

After that, the individual tablets T on each transport belt 21 are printed by the printing apparatus 50 based on the above-mentioned printing conditions at the timing based on the above-mentioned trigger signal, that is, at the timing when the tablets T reach the lower part of the print head 51. Will be executed. In each printing head 51 of the printing apparatus 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 tablet T is dried before the tablet T is recovered by the recovery device 60. When the ink-dried tablet T is located at the downstream end of each transport belt 21, it is released from the state of being held by each transport belt 21, drops from each transport 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 periodically performed for a predetermined time. When the maintenance operation is dummy ejection (when ink is ejected from the nozzle 51a by 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 pumping (when ink is discharged from the nozzle 51a by pressurization), the pumping execution interval is, for example, 30 to 40 minutes, and the pumping time is 30 to 60 seconds. It's ten seconds. Here, since the pumping time is longer than the dummy ejection time, in order to shorten the printing stop time associated with the maintenance of the print head 51, the number of maintenances by dummy ejection is increased and the number of maintenances by pumping is reduced. Is desirable. Therefore, by shortening the execution interval of dummy ejection and increasing the execution interval of pumping, 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 pumping, 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 step, the drive of each transfer belt 21 is not stopped, the supply of the tablet T to the transfer 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 tablet T is stopped, the unprinted tablet T that has not reached the lower part of the print head 51 on the transfer belt 21 reaches the lower part of the print head 51 sequentially for each transfer belt 21, and the print head 51. Will be printed by. After the printing is completed, each print head 51 is moved to a maintenance position facing the liquid receiving portion 71 by the moving device 72. Each print head 51 that has moved to the maintenance position performs dummy ejection or pumping for a predetermined time. After the maintenance operation is completed, each print head 51 is moved by the moving device 72 to the original printing position facing the transport belt 21. After that, the supply of the tablet T is restarted by the feeding device 10, and printing is restarted by each printing 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 staggered.

According to such a maintenance step, the supply of the tablet T is stopped for maintenance, but the stop time is suppressed. In either of the two print heads 51, the moving distance during maintenance is almost the shortest, so that the moving time of each print head 51 can be shortened.

As described above, according to the first embodiment, the liquid receiving unit 71 that functions as the maintenance unit of the maintenance device 70 is provided between the two transport 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 a liquid) toward the tablet T conveyed by the conveying belt 21 and a maintenance position for ejecting ink toward the liquid receiving portion 71. do. As a result, the moving distance of both of the two print heads 51 during maintenance is shorter than in the case where one liquid receiving portion 71 is provided on the outside of either of the two transport belts 21 instead of between the two transport belts 21. , It is possible to shorten the moving time of each print head 51. As a result, the print stop time associated with the maintenance of the print head 51 is shortened, so that it is possible to suppress a decrease in productivity 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 one as compared with the case where the liquid receiving portion 71 is provided on the outside of each of the two transport belts 21. Therefore, it is possible to realize the miniaturization of the tablet printing apparatus 1.

As described above, the print heads 51 are offset from each other in the transport direction A1, but the present invention is not limited to this, and the print heads 51 may not collide with each other on the liquid receiving portion 71. Therefore, the print heads 51 for each of the transport belts 21 may be positioned on the same straight line, and diagonal or curved movement paths may be provided so that the movement paths of the print heads 51 do not overlap. Further, even if the movement paths of the print heads 51 overlap, the timing may be shifted so that the print heads 51 do not enter maintenance at the same timing.

(Second Embodiment)
The second embodiment will be described with reference to FIG. In the second embodiment, the differences from the first embodiment (the number of print heads and the 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 four print positions are provided. Here, for simplification of the description, the four print heads 51 are distinguished as the first print head 51, the second print head 51, the third print head 51, and the fourth print head 51, and in FIG. Reference numerals 1, 2, 3 and 4 are written on the four print heads 51 of the above.

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 share one maintenance position, and the second print head 51 and the fourth print head 51 share one maintenance position. ..

In the first maintenance step (alternate printing), the first print head 51 and the second print head 51 do not print at the same time, and when one of them is printing, the other is performing maintenance. do. Similarly, the third print head 51 and the fourth print head 51 do not print at the same time, and if one of them is printing, the other is performing maintenance. Further, the print heads 51 of the set sharing the maintenance position do not execute printing at the same time.

For example, when a predetermined time has elapsed from the start of printing by the first print head 51 and the fourth print head 51, the first print head 51 and the fourth print head 51 stop printing and are waiting together. The second print head 51 and the third print head 51 of the above start printing. After the switching of the print head 51 is completed, the first print head 51 and the fourth print head 51 move from the print position to the maintenance position, respectively, and start maintenance. After that, when the maintenance is completed, the first print head 51 and the fourth print head 51 move from the maintenance position to the print position, respectively, and wait for the next print.

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

The maintenance is executed at predetermined time intervals, and the predetermined time in the first maintenance step is set to a time during which the print head 51 waiting at the print 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 out, resulting in ejection failure. Therefore, the above-mentioned predetermined time is set experimentally or theoretically in advance so that the discharge 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 prints, it moves to the maintenance position and performs dummy ejection before printing. It is also possible to return to the print position and start printing. Further, since the print heads 51 of the set sharing the maintenance position do not execute printing at the same time, the print heads 51 of each conveyor belt 21 do not move to the maintenance position at the same time, and the print heads 51 are in the maintenance position. Will not collide.

In the second maintenance step (all printing), each printing head 51 prints together. The first print head 51 and the second print head 51 take turns printing at predetermined time intervals (for example, 1 minute). Similarly, the third print head 51 and the fourth print head 51 also take turns printing at predetermined time (for example, 1 minute). A maintenance target is selected by the control device 90 from each of these print heads 51 based on the number of individual drives, and maintenance is executed for the selected print head 51. Since the intervals at which the tablets T are conveyed are not constant, the frequency of use of each print head 51 is different.

The control device 90 can grasp the individual number of times each print head 51 is driven (for example, the number of times a drive element is driven), and prints to be maintained from each print head 51 according to each number of times of drive. Select the head 51. For example, among the print heads 51, the print head 51 whose drive count has reached a predetermined number of times is designated as the print head 51 to be maintained. However, the control device 90 does not make the first print head 51 and the second print head 51 subject to maintenance at the same time, and does not make the third print head 51 and the fourth print head 51 subject to maintenance at the same time. Adjust the above selections as such. Similarly, in the control device 90, the first print head 51 and the third print head 51 are not subject to maintenance at the same time, and the second print head 51 and the fourth print head 51 are subject to maintenance at the same time. Adjust the above selections so that they do not.

According to the first or second maintenance step described above, the supply of the tablet T is not stopped due to maintenance, the tablet T is sequentially supplied to each transport belt 21, and is supplied by any of the print heads 51. Printing is performed. As a result, the printing stop time due to the maintenance of the print head 51 is eliminated, so that it is possible to suppress a decrease in productivity due to the print stop due to the maintenance.

Further, in the second maintenance step, by counting the number of times each print head 51 is driven individually, maintenance can be performed according to the actual frequency of use of the print head 51. As a result, unnecessary maintenance can be omitted, productivity can be increased, and stable printing can be performed even on tablets T that are randomly transported. In addition to the number of times the drive element is driven for each print head 51, for example, each print head 51 is subject to maintenance according to the number of times of printing 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, the same effects as those of the first embodiment can be obtained. Further, since printing is continued by any of the print heads 51, it is possible to eliminate the printing stop time due to maintenance and suppress the decrease in productivity due to the print stop due to maintenance.

(Third Embodiment)
The third embodiment will be described with reference to FIG. In the third embodiment, the differences from the first embodiment (the number of print heads and the 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 four print positions are provided. Here, for simplification of the description, the four print heads 51 are distinguished as the first print head 51, the second print head 51, the third print head 51, and the fourth print head 51, and in FIG. Reference numerals 1, 2, 3 and 4 are written on the four print heads 51 of the above. Further, the two transport belts 21 are distinguished as the first transport belt 21 and the second transport belt 21, and reference numerals 1 and 2 are shown on the two transport belts 21 in FIG.

The first print head 51 and the second print head 51 are arranged in the Y direction. Further, 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 move 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 move together in the Y direction by the moving mechanism 72b. The first print head 51 and the second print head 51 share one maintenance position, and the third print head 51 and the fourth print head 51 share one maintenance position. ..

In the first print head 51 and the second print head 51, when the first print head 51 is present at the print position of the first transfer belt 21, the second print head 51 is present at 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 transfer belt 21. Similarly, in the third print head 51 and the fourth print head 51, when the third print head 51 is present at the maintenance position, the fourth print head 51 is located at the print position of the second transfer belt 21. exist. When the third print head 51 is present at the print position of the first transfer belt 21, the fourth print head 51 is present at the maintenance position.

In the maintenance process, 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 print 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 transfer belt 21, and the third print head 51 moves from the maintenance position to the print position of the first transfer 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, respectively, from the print position. Move to the maintenance position and start maintenance. Along with this movement, the first print head 51 moves from the maintenance position to the print position of the first transfer belt 21, and the fourth print head 51 moves from the maintenance position to the print position of the second transfer belt 21. And start printing. Such processing is repeated.

The maintenance is executed at predetermined time intervals, and the predetermined time in the maintenance process is set to a time during which the print head 51 waiting at the print 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 out, resulting in ejection failure. Therefore, the above-mentioned predetermined time is set experimentally or theoretically in advance so that the discharge 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 prints, dummy ejection is performed before moving to the print 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 tablet T is not stopped for maintenance, and the tablet T is sequentially supplied to each transport belt 21 and printed by any of the print heads 51. As a result, the printing stop time due to the maintenance of the print head 51 is eliminated, so that it is possible to suppress a decrease in productivity due to the print stop due to the maintenance.

The moving speed of each print head 51 and the like are set so that unprinted tablets T are not generated during the movement of each print head 51. However, if the separation 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 each print head 51, so that the supply of the tablets T is stopped for a predetermined time (several seconds). Then, the separation distance of the tablets T adjacent to each other in the X direction is increased. This makes it 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, the same effect as that of the first embodiment can be obtained. Further, since printing is continued by any of the print heads 51, it is possible to eliminate the printing stop time due to maintenance and suppress the decrease in productivity due to the print stop due to 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 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 unit 74 in addition to the liquid receiving unit 71 and the like. The bottom surface of the liquid receiving portion 71 is inclined so as to be gradually lowered toward either end of the bottom surface in the Y direction. A discharge port 71a is formed at one end thereof, and one end of the discharge pipe 73 is connected to the discharge port 71a. The other end of the discharge pipe 73 is connected to the storage unit 74. The ink discharged from each nozzle 51a of the print head 51 existing 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 that has flowed out of the discharge pipe 73. The bottom surface of the liquid receiving portion 71 may be inclined in any direction, and may be inclined toward the portion where the discharge port 71a is formed. Further, the number of the discharge port 71a, the discharge pipe 73, and the storage portion 74 is not particularly limited.

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

In the maintenance step, the ink discharged from each nozzle 51a of the print head 51 existing 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 71a, flows into the storage unit 74 through the discharge pipe 73, and is stored by the storage unit 74. In the maintenance process by pumping, the amount of ink discharged from each nozzle 51a of the print head 51 is larger than that in the maintenance process by dummy ejection. If a large amount of ink accumulates on the bottom surface of the liquid receiving portion 71, there is a high tendency for liquid splashing to occur during the next maintenance. Therefore, by providing the discharge pipe 73 and the storage portion 74, it is possible to prevent a large amount of ink from accumulating 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. ..

As described above, according to the fourth embodiment, the same effects as those of the first embodiment can be obtained. 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 and the transport belt 21 due to liquid splashing (as an example). (Belt surface on which the tablet T is placed), contamination of the tablet T during transportation and the like can be suppressed.

(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 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 the bottom surface thereof. As an example, the convex portion 71b has a mountain shape whose top extends in the X direction, and is formed so that the ink discharged from each nozzle 51a of the print head 51 existing 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 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 from end to end where the ink discharged from each nozzle 51a of the print head 51 existing at the maintenance position on the bottom surface is landed. The shape of the convex portion 71b may be a mountain shape having a single point at the top, or a V-shape or a funnel shape.

In the maintenance process, the ink discharged from each nozzle 51a of the print head 51 existing 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 flows in the Y direction on the bottom surface. Move towards both ends of the. Here, if the bottom surface of the liquid receiving portion 71 is flat, the ink collects in the landing region where the ink hits on the bottom surface, so that the liquid splash tends to occur at the time of the next maintenance or the like. Therefore, by providing the convex portion 71b on the bottom surface of the liquid receiving portion 71, the ink discharged from each nozzle 51a of the print head 51 existing at the maintenance position flows along each inclined surface of the convex portion 71b and receives the liquid. It will collect 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 region 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, if the bottom surface is flat, the direction of liquid splashing becomes random, but the direction of liquid splashing can be adjusted to some extent by adjusting the angle of each inclined surface.

As described above, according to the fifth embodiment, the same effects as those of the first embodiment can be obtained. 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 region on the bottom surface of the liquid receiving portion 71, so that the print head 51 and the transport belt due to liquid splashing can be suppressed. 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 can be suppressed.

(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 other description will be omitted.

As shown in FIG. 8, the maintenance device 70 according to the sixth embodiment includes a plurality of suction pipes 76 and a suction section 77 in addition to the liquid receiving section 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 portion 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 recovery unit such as a liquid trap, a filter (none of which 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. These suction ports 71c are formed in a size that allows ink ejected from each nozzle 51a of the print head 51 existing at the maintenance position to pass through and does not bounce off. 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 from end to end where the ink discharged from each nozzle 51a of the print head 51 existing at the maintenance position on the bottom surface 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 discharged from each nozzle 51a of the print head 51 existing at the maintenance position passes through the suction port 71c of the liquid receiving portion 71 and is sucked by the suction tube 76. This ink flows through the suction tube 76 and is collected by the liquid recovery unit of the suction unit 77. The suction unit 77 is driven at the time of maintenance execution, and is not driven at normal times other than the maintenance execution time. However, it is also possible to share the suction device of the transport device 20 as the suction unit 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 mist may be generated due to the flying droplets. 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 droplets from flying up, that is, the generation of mist during maintenance. Become. As a result, contamination of the print head 51 and the transport belt 21 around the liquid receiving portion 71 by the mist can be suppressed.

As described above, according to the sixth embodiment, the same effects as those of the first embodiment can be obtained. 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 prevent the droplets from flying up, that is, the generation of mist during maintenance. Therefore, it is possible to suppress contamination of the print head 51 and the transport belt 21 around the liquid receiving portion 71 by the mist.

(7th Embodiment)
A seventh embodiment will be described with reference to FIG. In the seventh embodiment, the differences (maintenance device) from the sixth embodiment will be described, and 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 each suction tube 76 is individually connected to the suction ports 71c. The two suction ports 71c are formed at both ends in the Y direction on the bottom surface of the liquid receiving portion 71. 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 via the suction ports 71c, respectively. As described above, the mist is generated when the ink ejected from the print head 51 existing at the maintenance position hits the bottom surface of the liquid receiving portion 71 and splashes, and the droplets fly 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 discharged from each nozzle 51a of the print head 51 existing 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 in the center of the bottom surface. At this time, even if mist is generated due to the soaring of the droplets, the mist is sucked together with the air by the two suction tubes 76. As a result, the mist can be removed during maintenance, so that the mist can suppress contamination of the print head 51 and the transport belt 21 around the liquid receiving portion 71.

It is also possible to connect a discharge pipe (not shown) 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 by the discharge pipe. As a result, it is possible to prevent ink from accumulating in the landing region 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, the same effects as those of the first embodiment can be obtained. 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 soaring droplets during maintenance, so that the print head 51 and the liquid due to the mist can be removed. Contamination of the transport belt 21 and the like around the receiving portion 71 can be suppressed.

(8th Embodiment)
The eighth embodiment will be described with reference to FIG. In the eighth embodiment, the differences (maintenance device) from the seventh embodiment will be described, and 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 portion 78 is arranged so as to face each suction port 71c of the liquid receiving portion 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 spraying portion 78. Therefore, the gas spraying unit 78 blows out gas (for example, air or nitrogen) downward to form a curtain made 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 step, each gas spraying unit 78 is driven by the control device 90, air (an example of gas) is blown out from the gas spraying unit 78, and is sucked from the two suction ports 71c of the liquid receiving unit 71. As a result, airflow curtains, that is, air curtains (an example of a gas curtain) 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, mist may be generated due to the soaring of droplets, but the mist is formed along with air along the flow of the air curtain in two suction tubes. Aspirated by 76. Further, even if a large amount of mist is generated, the air curtain prevents the mist from flowing out to the transport belt 21 side from the opening at the upper part of the liquid receiving portion 71. In this way, it is possible to remove the mist during maintenance and further suppress the outflow of the mist, 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 by the mist. Further, by sucking the gas from below the gas spraying portion 78 (lower suction), it is possible to suppress the width of the air curtain from expanding, and it is possible to prevent the printing near the air curtain from being affected. ..

Further, as shown in FIG. 11, in the modified example, in addition to the above-mentioned two gas blowing portions 78, a suction head 79 is provided for each gas blowing portion 78. The gas spraying portion 78 applies gas parallel to the transport direction A1 of the tablet T toward between the transport belt 21 and the liquid receiving portion 71 so as to form an air curtain between the transport belt 21 and the liquid receiving portion 71. Blow out. The suction head 79 is formed in a gutter shape with an upper surface 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 portion 78 and at a position lower than the liquid receiving portion 71, and the suction port 79a is provided so as to face the gas spraying portion 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 that has been blown out from the gas spraying portion 78 and has passed between the transport belt 21 and the liquid receiving portion 71. As a result, the air curtain is formed on the outside of the liquid receiving portion 71, and is formed along the stretching direction of the transport belt 21, that is, along the transport direction A1 (for example, parallel to the transport belt 21). The suction mechanism by the suction head 79 or the suction pipe 76 described above is not indispensable, and only the air curtain may be formed.

As described above, according to the eighth embodiment, the same effects as those of the first embodiment can be obtained. Further, by providing the gas spraying portion 78, even if a large amount of mist is generated, the mist flows out to the transport belt 21 side from the opening at the upper part of the liquid receiving portion 71 by an air curtain (an example of an air flow curtain). Since it is possible to suppress it, it is possible to reliably suppress the contamination of the transport belt 21 and the like around the liquid receiving portion 71 by the mist.

(Other embodiments)
In each of the above-described embodiments, it has been illustrated that the hopper 11 and the shooter 12 are used as the supply device 10, but the present invention is not limited to this, and various supply mechanisms can be used. For example, a delivery mechanism for sucking and transporting the tablet T is provided on the lower surface, and the tablet T can be supplied to the transport device 20 by this delivery mechanism. In this case, in order to stop the supply of the tablet T to the transport device 20, the suction by the delivery mechanism may be stopped.

Further, in each of the above-described embodiments, the transport of the tablets T in two rows is illustrated by the transport belt 21, but the present invention is not limited to this, and may be 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 for example, a print head 51 may be provided for each row.

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

Further, in each of the above-described embodiments, as the transport device 20, a transport device that holds and transports the tablet T by suction is exemplified, but the present invention is not limited to this, and various transport mechanisms can be used. .. Further, as a holding mechanism for sucking and holding the tablet T, it has been exemplified that the tablet T is held by a slit-shaped suction port 21a extending in the transport direction A1, but the present invention is not limited to this, and for example, in the transport direction A1. The tablet 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 taken based on the detection device 30, but the printing timing is not limited to this, and for example, the printing timing may be taken based on the image pickup device 40. ..

Further, in each of the above-described embodiments, as the inkjet printing head 51, a printing head in which the nozzles 51a are arranged in a row has been exemplified, but the present invention is not limited to this, and for example, a printing head in which the nozzles 51a are arranged in a plurality of rows is used. You may use it.

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

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

Here, the above-mentioned tablets may include tablets used for pharmaceuticals, foods and drinks, cleaning, industrial use or aromatic use. Further, for example, as tablets, there are naked tablets (bare tablets), sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-encapsulated tablets, multi-layer tablets, nucleated tablets and the like. Furthermore, various capsule tablets such as hard capsules and soft capsules can also be included in the tablets. Further, as the shape of the tablet, there are various shapes such as a disk shape, a lens shape, a triangle shape, and an ellipse shape.

When the tablet to be printed is for pharmaceutical use or food and drink, edible ink is suitable as the ink to be used. Specifically, as edible pigments, amaranth, erythrosine, ponceau (above, red), tartrazine, sunset yellow FCF, β-carotene, crocin (above, yellow), brilliant blue FCF, indigo carmine (above, blue). ) And the like, and these are dispersed or dissolved in a vehicle, and if necessary, a dye dispersant (surfactant) is blended. 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 embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Tablet printing device 21 Conveying 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

The tablet printing apparatus according to the embodiment of the present invention is a maintenance unit provided between at least two transport paths provided in parallel in a horizontal plane and two transport paths for transporting tablets to perform maintenance. When provided around the an upper maintenance of the conveying path for each transport path, and the print head of an ink jet method of discharging liquid from a nozzle, respectively each print head is provided for each print head, the conveying device above the printing position and the maintenance unit upper of the mobile device for individually moved to the maintenance position, comprising a print head, which are arranged in the conveying direction of the two or more tablets each conveyance path, the maintenance position, the conveying direction It is provided for each set of print heads arranged in the intersecting direction, and the moving device is characterized in that each print head is individually moved so as to share a maintenance position for each set of print heads .

The tablet printing apparatus according to the embodiment of the present invention is a maintenance unit provided between at least two transport paths provided in parallel in a horizontal plane and two transport paths for transporting tablets to perform maintenance. An inkjet print head that is provided above the transport path for each transport path and corresponds to the printing position around the maintenance unit and ejects liquid from the nozzle, and each print head is provided for each print head. provided, and a moving device for moving the print head to the printing position and the maintenance unit upper maintenance position of the transport path above, the print head and arranged in a direction intersecting the transport direction of the two or more tablets The maintenance position is provided for each set of print heads arranged in a direction intersecting the transport direction, and the moving device sets each print head to a set of print heads so as to share the maintenance position for each set of print heads. It is characterized by moving each time .

Claims (4)

At least two parallel transport paths in the horizontal plane to which the tablets are transported, and
A maintenance unit provided between the two transport paths and performing maintenance,
An inkjet printing head that is provided above the transport path for each transport path and is provided around the maintenance section to discharge liquid from a nozzle.
A moving device for individually moving each of the printing heads to a printing position above the transport device and a maintenance position above the maintenance unit, which is provided for each printing head.
With
Two or more of the print heads are arranged in the transport direction of the tablet 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 moving device is a tablet printing device, characterized in that each of the printing heads is individually moved so as to share the maintenance position for each set of the printing heads. At least two parallel transport paths in the horizontal plane to which the tablets are transported, and
A maintenance unit provided between the two transport paths and performing maintenance,
An inkjet print head that is provided above the transport path for each transport path and corresponds to a printing position around the maintenance unit and discharges liquid from a nozzle.
A moving device for moving each of the print heads to a print position above the transport path and a maintenance position above the maintenance unit, which is provided for each print head.
With
Two or more of the print heads are arranged in a direction intersecting the transport direction of the tablet.
The maintenance position is provided for each set of the print heads arranged in a direction intersecting the transport direction.
The moving device is a tablet printing device, characterized in that each printing head is moved for each set of printing heads so as to share the maintenance position for each set of printing heads. The moving device according to claim 1, wherein each printing head is individually moved so that at least one of the two or more printing heads is present at the printing position for each transport path. Tablet printing equipment. The moving device moves each print head for each set of print heads so that at least one of the two or more print heads is in the print position and the other one is in the maintenance position. The tablet printing apparatus according to claim 2.

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