KR20230136544A - Tablet printing apparatus and tablet printing method - Google Patents

Abstract

The present invention makes it possible to suppress the occurrence of printing defects and the deterioration of ink.
The tablet printing device according to the embodiment includes a conveyance unit 21 provided in the first region R1, which suctions and holds the tablets in the suction hole 21g and conveys them, and is provided in the first region R1, and conveys the tablets. An inkjet head 24 that prints on the tablet conveyed by the unit 21, a heat source 62 provided in the second area R2 following the first area R1, and an inkjet head 24 in the first area R1. It is provided with a cooling unit 61 that supplies gas at a temperature lower than that of the second region R2.

Description

Tablet printing apparatus and tablet printing method {TABLET PRINTING APPARATUS AND TABLET PRINTING METHOD}

Embodiments of the present invention relate to tablet printing devices and tablet printing methods.

Currently, tablet printing devices that perform printing using an inkjet head have been developed to print various information such as identification information on tablets. Among these tablet printing devices, there is a device that uses an inkjet head to print tablets held in suction holes. In this device, inside the area where printing is performed by the inkjet head, a camera, a detection sensor, a control board that controls the inkjet head, etc., a blower used to suction and hold the tablet, a motor used to transport the tablet, etc. are provided together. .

The control board, blower, motor, etc. serve as heat sources, and heated air flows into the suction hole side due to the suction used to maintain the tablet. Since the inkjet head exists above the suction hole, the temperature near the inkjet head rises due to the air flow described above. When the temperature near the inkjet head rises, the viscosity of the ink in the inkjet head decreases, making it impossible to eject a certain amount of ink, or the area near the nozzle dries and ink sticks to the nozzle. This may cause ejection defects and result in printing defects. Alternatively, as the temperature near the inkjet head rises, the ink in the inkjet head becomes more likely to deteriorate.

Patent Document 1: Japanese Patent Publication No. 2013-122401

The problem to be solved by the present invention is to provide a tablet printing device and a tablet printing method that can suppress the occurrence of printing defects and the deterioration of ink.

A tablet printing device according to an embodiment of the present invention includes a conveyance unit provided in a first area for transporting tablets by sucking them into a suction hole, and the tablets provided in the first area and conveyed by the conveyance unit. It has an inkjet head that performs printing, a heat source provided in a second area adjacent to the first area, and a cooling unit that supplies gas at a temperature lower than that of the second area to the first area.

The tablet printing method according to an embodiment of the present invention includes a transport unit provided in a first area transporting the tablet by holding it by suction into a suction hole, and an inkjet head provided in the first area transporting the tablet by the transport unit. Printing on tablets, and in a state where a heat source is present in a second region following the first region, a cooling unit supplies gas at a temperature lower than the temperature of the second region to the first region. do.

According to the embodiment of the present invention, occurrence of printing defects and deterioration of ink can be suppressed.

1 is a diagram showing an example of the schematic configuration of a tablet printing device according to an embodiment.
Fig. 2 is a diagram showing an example of the schematic configuration of a printing device according to the embodiment.
FIG. 3 is a diagram for explaining the cooling function of the tablet printing device according to the embodiment, and is a cross section taken along line X1-X1 of FIG. 2.
FIG. 4 is a diagram showing an example of a case of the tablet printing device according to the embodiment, and is an arrow diagram viewed from the direction of arrow Y1 in FIG. 2.
Fig. 5 is a diagram showing an example of a partition member according to the embodiment.
Figure 6 is a diagram showing an example of a partition member according to the embodiment.
Fig. 7 is a diagram showing an example of a partition member according to the embodiment.
Fig. 8 is a diagram showing an example of a control device according to the embodiment.
Figure 9 is a diagram for explaining the retraction function of the inkjet head according to the embodiment.
Figure 10 is a flowchart showing an example of the flow of the printing process according to the embodiment.

<Embodiment>

One embodiment will be described with reference to the drawings.

(Configuration example of tablet printing device)

A configuration example of the tablet printing device 1 according to the embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1 , the tablet printing device 1 according to the embodiment includes a supply device 10, a printing device 20, a recovery device 30, and a control device 40.

The supply device 10 has a hopper 11, an alignment feeder 12, and a delivery feeder 13. This supply device 10 is located at one end of the printing device 20 and is configured to supply tablets T, which are the printing objects, to the printing device 20. The hopper 11 accommodates a plurality of tablets T, and sequentially supplies the accommodated tablets T to the sorting feeder 12. The alignment feeder 12 aligns the supplied tablets T in a row and conveys them in the conveyance direction A1 (clockwise) toward the delivery feeder 13. The delivery feeder 13 holds each tablet T lined up on the alignment feeder 12 by sequentially suctioning it from the upper side of the tablet T, and prints each tablet T held in a row by the printing device 20. It is conveyed in a row and delivered to the printing device 20. As the alignment feeder 12, for example, a belt conveyance mechanism or a vibration feeder is used. As the delivery feeder 13, for example, a belt conveyance mechanism is used. The belt conveyance mechanism of this delivery feeder 13 is rotating in the conveyance direction A2 (counterclockwise). The supply device 10 is electrically connected to the control device 40, and its driving is controlled by the control device 40.

The printing device 20 includes a conveyance unit 21, a detection unit 22, a first imaging unit 23, an inkjet head 24, a second imaging unit 25, and a movement mechanism 26. and a maintenance unit 27 and a drying unit 28.

Here, as shown in FIG. 2, the detection unit 22, the first imaging unit 23, the inkjet head 24, and the second imaging unit 25 are provided, for example, two each, but their number is particularly limited. It is not possible and is set according to the number of return routes for tablets (T). In addition, since the configuration of each detection unit 22, the configuration of each first imaging unit 23, the configuration of each inkjet head 24, and the configuration of each second imaging unit 25 are the same, each is described below. Explain one of them.

Returning to FIG. 1, the transport unit 21 includes a transport belt 21a, a drive pulley 21b, a plurality of driven pulleys 21c, a motor 21d, a position detector 21e, and a suction chamber 21f. have The conveyance belt 21a is an endless belt, and is installed on the drive pulley 21b and each driven pulley 21c. The drive pulley 21b and each driven pulley 21c are rotatably provided in the device main body (not shown), and the drive pulley 21b is connected to the motor 21d. The motor 21d is electrically connected to the control device 40, and its driving is controlled by the control device 40. The position detector 21e is a device such as an encoder, and is attached to the motor 21d. This position detector 21e is electrically connected to the control device 40 and transmits a detection signal to the control device 40. The transport unit 21 moves the transport belt 21a together with each driven pulley 21c by rotating the drive pulley 21b by the motor 21d, thereby transporting the tablets T on the transport belt 21a. Convey in the conveying direction (A1) (clockwise).

As shown in FIG. 2, a plurality of circular suction holes 21g are formed on the conveyance belt 21a. These suction holes 21g are through holes for adsorbing the tablet T, respectively, and are arranged in two rows along the conveyance direction A1 to form two conveyance paths extending in parallel. Each suction hole 21g is connected to the suction chamber 21f through a suction path (not shown) formed in the suction chamber 21f (see FIG. 1), and suction force can be obtained by the suction chamber 21f. It is meant to be. A blower is connected to the suction chamber 21f through a suction pipe (not shown), and the pressure inside the suction chamber 21f is reduced by the operation of the blower. The suction pipe is connected to approximately the center of the side surface (plane parallel to the conveyance direction A1) of the suction chamber 21f. Additionally, the blower is electrically connected to the control device 40, and its driving is controlled by the control device 40. When the pressure inside the suction chamber 21f is reduced, the tablets T placed on each suction hole 21g of the conveyance belt 21a are attracted by the suction hole 21g and are held on the conveyance belt 21a.

The detection unit 22 is located downstream in the conveyance direction A1 from the position where the supply device 10 is provided, and is provided above the conveyance path formed by the suction hole 21g. This detection unit 22 detects the tablet T that has reached the detection position immediately below the detection unit 22 by the transmitted light of the laser light (arrival of the tablet T), that is, on the conveyance belt 21a. The position of the tablet T in the X direction (see Figure 2) is detected. Additionally, the detection unit 22 detects the height of the tablet T on the conveyance belt 21a. As the detection unit 22, for example, a displacement sensor is used. Additionally, as a displacement sensor, various laser sensors such as a reflective laser sensor are used. The detection unit 22 is electrically connected to the control device 40 and transmits a detection signal to the control device 40.

The first imaging unit 23 is located downstream in the conveyance direction A1 from the position where the detection unit 22 is provided, and is provided above the conveyance path formed by the suction hole 21g. This first imaging unit 23 detects the tablet T at an imaging position immediately below the first imaging unit 23, based on the position information of the tablet T in the X direction detected by the detection unit 22. Imaging is performed at the first imaging timing reached, a first image including the upper surface of the tablet T is acquired, and the acquired first image is transmitted to the control device 40. The first image is used to detect the positions of the tablet T in the ) is used to detect the presence or absence of As the first imaging unit 23, various cameras having imaging elements such as CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor) are used. The first imaging unit 23 is electrically connected to the control device 40, and its driving is controlled by the control device 40. Additionally, lighting for imaging is also provided as needed.

Here, the positions of the tablet T in the X direction and Y direction are, for example, the positions of the In addition, the position in the θ direction is, for example, a position indicating the degree of rotation of the tablet T within a horizontal plane along the XY plane of the imaging area of the first imaging unit 23. The position in the θ direction is detected when the tablet (T) has a directional shape, such as when the tablet (T) is provided with a secant line or when the tablet (T) is molded into an oval, oval, square, etc. do. Additionally, the X direction and Y direction are positions in the horizontal direction.

The first imaging unit 23 also includes a cover 23a (see FIG. 2). The cover 23a corresponds to the first cover and is a member for preventing foreign matter from adhering to the light-receiving portion of the first imaging unit 23. The cover 23a is in non-contact with the conveyance belt 21a and is provided to surround the first imaging unit 23. The lower end of the cover 23a is at the same height as the retracted position H3 of the inkjet head 24, which will be described later (see Fig. 9). The lower end of the cover 23a does not necessarily have to be at the same height as the retracted position H3 of the inkjet head 24, and may be at a height that does not contact the tablet T. The cover 23a is made of metal such as stainless steel, for example.

The inkjet head 24 is located downstream in the conveyance direction A1 from the position where the first imaging unit 23 is provided, and is provided above the conveyance path formed by the suction hole 21g. The inkjet head 24 has a plurality (e.g., hundreds to thousands) of nozzles 24a (see FIG. 2), and the direction in which the nozzles 24a are lined up (nozzle row) is the conveyance direction in the horizontal plane ( It is arranged to be orthogonal to A1) (an example of intersection). The inkjet head 24 individually discharges ink from each nozzle 24a by the operation of the drive element for each nozzle 24a. As this inkjet head 24, various inkjet type print heads having driving elements such as piezoelectric elements, heating elements, or magnetostrictive elements are used. The inkjet head 24 is electrically connected to the control device 40, and its driving is controlled by the control device 40.

The second imaging unit 25 is located downstream in the conveyance direction A1 from the position where the inkjet head 24 is provided, and is provided above the conveyance path formed by the suction hole 21g. This second imaging unit 25 detects the tablet T at an imaging position immediately below the second imaging unit 25, based on the position information of the tablet T in the X direction detected by the detection unit 22. Imaging is performed at the second imaging timing reached, a second image including the upper surface of the tablet T is acquired, and the acquired second image is transmitted to the control device 40. The second image is used to inspect the print pattern printed on the tablet T. As the second imaging unit 25, similar to the above-described first imaging unit 23, various cameras having an imaging device such as CCD or CMOS, for example, are used. The second imaging unit 25 is electrically connected to the control device 40, and its driving is controlled by the control device 40. Lighting for imaging is also provided as needed.

The second imaging unit 25 also includes a cover 25a (see FIG. 2). The cover 25a corresponds to the second cover and is a member for preventing foreign matter from adhering to the light-receiving portion of the second imaging unit 25. The cover 25a is not in contact with the conveyance belt 21a and is provided to surround the second imaging unit 25. The lower end of the cover 25a is at the same height as the retracted position H3 of the inkjet head 24, which will be described later (see Fig. 9). The lower end of the cover 23a does not necessarily have to be at the same height as the retracted position H3 of the inkjet head 24, and may be at a height that does not contact the tablet T. The cover 25a is made of metal such as stainless steel, for example.

The moving mechanism 26 moves each inkjet head 24 in the upward and downward direction (up and down direction in FIG. 1). As shown in FIG. 2, this moving mechanism 26 has, for example, an arm 26a and an arm moving mechanism 26b. The arm 26a is a holding portion that holds each inkjet head 24. For example, the arm 26a holds the discharge surface of each inkjet head 24 opposite to the transport surface of the transport belt 21a. The conveyance surface of the conveyance belt 21a is the surface on which the tablets T are placed on the conveyance belt 21a and is the surface of the conveyance belt 21a on the inkjet head 24 side. The discharge surface of the inkjet head 24 is the surface of the inkjet head 24 on which the nozzle 24a is formed, and is the surface of the inkjet head 24 on the side of the conveyance belt 21a. The arm moving mechanism 26b is a mechanism that holds the arm 26a and moves it in the raising/lowering direction. This arm moving mechanism 26b is provided at a position adjacent to the side surface (plane parallel to the conveyance direction A1) of the suction chamber 21f. As the arm moving mechanism 26b, for example, a linear guide mechanism is used. The arm moving mechanism 26b is electrically connected to the control device 40, and its driving is controlled by the control device 40. This movement mechanism 26 raises and lowers the arm 26a, that is, each inkjet head 24 by the arm movement mechanism 26b, so that the conveyance surface of the conveyance belt 21a and the discharge surface of each inkjet head 24 are aligned. It is possible to change the spacing (separation distance).

Additionally, in this embodiment, the maximum raised position of the inkjet head 24 is the maintenance position H2, which will be described later. However, the maximum raised position of the inkjet head 24 is not limited to this. The maximum rising position of the inkjet head 24 may be a position higher than the maintenance position H2. In other words, the maximum elevation position can be any height that prevents the area around the nozzle of the inkjet head 24 from drying out due to the cooling unit 61, which will be described later. However, the lower the maximum elevation position of the inkjet head 24, the lower the ceiling height of the cover 53, which will be described later. The lower the ceiling height of the cover 53, the smaller the volume of the space covered by the cover 53. Therefore, the cooling efficiency of the cooling unit 61, which will be described later, can be improved.

The maintenance unit 27 performs maintenance operations on each inkjet head 24. Maintenance operations include, for example, wiping operations and ink receiving operations. As shown in FIG. 2, the maintenance unit 27 has, for example, a wiping unit 27a and a receiving plate 27b. The wiping unit 27a is a cleaning unit that cleans the discharge surface of each inkjet head 24 by reciprocating the maintenance unit 27 in the Y direction (see FIG. 2). The receiving plate 27b is a receiving member that receives the liquid droplets ejected from each inkjet head 24. This maintenance unit 27 is provided at a position adjacent to the side surface of the suction chamber 21f (a surface parallel to the conveyance direction A1), and is connected to the conveyance surface of the conveyance belt 21a and each inkjet head 24. It is configured to be movable between the discharge surfaces by a moving mechanism (for example, a linear guide mechanism) not shown. In addition, when performing maintenance, the gap between the conveyance surface of the conveyance belt 21a and the discharge surface of each inkjet head 24 is set by a moving mechanism ( 26).

The drying unit 28 is arranged in a position opposite to the transport belt 21a, and is provided below the transport unit 21, for example. This drying section 28 dries the ink applied to each tablet T on the conveyance belt 21a. As the drying unit 28, various dryers are used, such as a blower that performs drying with a gas such as air, a heater that performs drying with radiant heat, or a blower that performs drying with warm air or hot air using a combination of gas and a heater. . The drying unit 28 is electrically connected to the control device 40, and its operation is controlled by the control device 40.

The recovery device 30 is located downstream in the conveyance direction A1 from the position where the drying section 28 is provided, and is provided below the conveyance section 21. This collection device 30 has a reusable product collection unit 31, a defective product collection unit 32, and a good product collection unit 33. The recovery device 30 collects tablets T of reusable products through a reuse product recovery section 31, recovers tablets T of defective products through a defective product recovery section 32, and collects tablets T of defective products through a non-defective product recovery section 33. ) to recover the good quality tablets (T). For example, reusable products are reusable tablets, which are unprinted tablets that are intact and free of foreign matter. In addition, defective products are unprinted tablets with foreign matter attached or non-printable tablets that are intact and free of foreign matter (printed tablets), while good products are tablets that pass printing (printed tablets) that are intact and free of foreign substances. In addition, the listing order in the conveyance direction A1 in the reusable product collection unit 31, the defective product collection unit 32, and the good product collection unit 33 is not limited to the listing order shown in FIG. 1 and can be changed as appropriate. It's okay to be The recovery device 30 is electrically connected to the control device 40, and its driving is controlled by the control device 40.

The reuse collection unit 31 has a spray nozzle 31a and a collection box 31b. Additionally, the defective product collection unit 32 has a spray nozzle 32a and a collection box 32b. The non-defective product collection unit 33 has a spray nozzle 33a and a collection box 33b. These spray nozzles (31a, 32a, 33a) have basically the same structure, and each recovery box (31b, 32b, 33b) also has basically the same structure. For this reason, the injection nozzle 31a and the recovery box 31b will be explained as representatives.

The injection nozzle 31a and the recovery box 31b are provided at positions opposing each other across a conveyance path along which each suction hole 21g of the conveyance belt 21a is arranged. The injection nozzle 31a is disposed in the suction chamber 21f and, for example, sprays gas (e.g. air) toward the conveyance belt 21a, causing the tablets T to fall from the conveyance belt 21a. At this time, the gas injected from the injection nozzle 31a passes through the suction hole 21g of the conveyance belt 21a and reaches the tablet T. The injection nozzle 31a is electrically connected to the control device 40, and its driving is controlled by the control device 40. The collection box 31b is provided directly below the injection nozzle 31a and below the conveyance unit 21. This collection box 31b receives and accommodates the tablets T that have fallen from the conveyance belt 21a by the gas injected from the injection nozzle 31a.

Here, the tablets T that have passed through the reusable product collection unit 31 and the defective product collection unit 32 are conveyed by the movement of the conveyance belt 21a, and are connected to each driven pulley 21c in the conveyance belt 21a. ) reaches the position near the end of the side. At this position, the suction action no longer acts on the tablet T, but gas is sprayed onto the tablet T from above by the spray nozzle 33a, and the tablet T is moved to the conveyance belt 21a. falls from Therefore, by providing the injection nozzle 33a, the tablet T can be reliably dropped from the conveyance belt 21a. The recovery box 33b receives and accommodates the tablets T that have fallen from the conveyance belt 21a by the gas injected from the injection nozzle 33a.

The control device 40 controls each part of the tablet printing device 1, such as the supply device 10, the printing device 20, and the recovery device 30, based on various information and various programs. In addition, the control device 40 receives detection information (e.g., a detection signal) transmitted from the position detector 21e and the detection unit 22 of the conveyance unit 21, respectively, and also receives the first image pickup unit 23. I receive image information, etc. transmitted from the second imaging unit 25. The control device 40 is realized by, for example, an electronic circuit such as an integrated circuit or a computer.

(Cooling function of tablet printing device)

Next, the cooling function of the tablet printing device 1 will be explained with reference to FIGS. 2 to 7.

2 to 4, the tablet printing device 1 has a case 51. This case 51 contains each part included in the tablet printing device 1. Each part includes a supply device 10, a printing device 20, a recovery device 30, and a control device 40, and in the example of FIG. 3, a cooling unit 61 and a heat source 62, as well as a conveying unit 61. A unit 21, each inkjet head 24, a moving mechanism 26, and a maintenance unit 27 are shown.

Case 51 has a door 52, a door 55, and a cover 53. The door 52 and the door 55 are attached to the case 51 so that they can be opened and closed. An opening 52a is formed in the door 52. This opening 52a is sized to fit the exterior of the cooling unit 61, and when the door 52 is closed, the end of the cooling unit 61 on the door 52 side is inserted into the opening 52a. It is formed as much as possible. A gap member such as packing may be provided in this opening 52a. The case 51 has a holding portion 51a above the inkjet head 24 and above the heat source 62. The holding portion 51a is, for example, a planar plate that covers the upper sides of the inkjet head 24, the first imaging portion 23, and the second imaging portion 25. Above the holding portion 51a, an input device 40a, an output device 40b, etc., which will be described later, are accommodated. Below the holding portion 51a, the detection portion 22, the first imaging portion 23, the second imaging portion 25, etc. are accommodated. Additionally, a partition member 54 is provided between the transfer unit 21 and the heat source 62 inside the case 51.

The partition member 54 is a wall for dividing the first area R1 and the second area R2, and has this to prevent heat from the heat source 62 from flowing into the first area R1. there is. The partition member 54 is formed of, for example, a plate of metal such as stainless steel. The length of the partition member 54 in the X direction is equal to the length of the conveyance unit 21 in the X direction. The upper end of the partition member 54 is connected to the ceiling of the case 51, but is not necessarily connected to the ceiling of the case 51. A gap may be provided between the upper end of the partition member 54 and the ceiling of the case 51. There is a cable connecting the first imaging unit 23 or the second imaging unit 25 and the control board. The partition member 54 is provided with a hole (not shown) through which a cable or the like can pass. Additionally, as shown in FIGS. 4 and 5, the partition member 54 is provided with an opening 54a. The opening 54a is an opening for connecting the moving mechanism 26 to the inkjet head 24. Additionally, the opening 54a is also an opening for the maintenance unit 27 to pass between the first area R1 and the second area R2.

In this embodiment, the opening 54a is a notch. The outer shape of the opening 54a is T-shaped. For example, a portion of the rectangular or square-shaped partition member 54 is cut into a T-shape, and a T-shaped opening 54a is formed in the portion of the partition member 54. Specifically, the opening 54a is formed by cutting downward from the upper end of the partition member 54 in the Z direction. The length of the opening 54a in the X direction at the upper end of the partition member 54 is the same as the length of the door 52 . The length of the downwardly protruding portion of the opening 54a in the X direction is the same as the length of the cover 53 in the X direction. The opening 54a is provided at a position where the maintenance unit 27 and the partition member 54 intersect. That is, the upper end of the partition member 54 at the position where the protruding portion of the opening 54a is provided is at a height where the maintenance unit 27 can pass between the first area R1 and the second area R2. It is arranged to be located. In addition, the reason why the opening 54a is a T-shaped notch is to avoid interference between the partition member 54 and the holding portion 51a, and in the case where the holding portion 51a is not present, the opening 54a is T-shaped. It may be a notch in a shape other than a ruler, or it may be a hole in a shape such as a rectangle, square, or circle.

The partition member 54 may be formed of a single plate, as shown in FIG. 5, or may be formed by combining a plurality of plates 54b, as shown in FIG. 6. In this case, a plate 54b blocking the upper part of the holding portion 51a may be present. As shown in FIG. 7 , the partition member 54 may be formed of a plurality of plates 54b and a frame 54c attachable to the case 51. Additionally, instead of the frame 54c, a plurality of plates 54b may be attached to pillars or beams of the case 51.

Returning to Figures 2 and 3, the cover 53 is a cover member that blocks the space above the conveyance unit 21 from the door 52 side (front side). At least each inkjet head 24 exists in the space surrounded by the cover 53. In addition, the cover 53 is attached to the partition member 54 so as to cover a part of the opening 54a of the partition member 54, and is a cover that blocks the space above the conveyance unit 21. That is, the space surrounded by the cover 53 communicates with the opening 54a of the partition member 54. Additionally, in this embodiment, the upper part of the opening 54a cannot be covered with the cover 53 because it is partitioned by the holding portion 51a. However, if the cover 53 can cover the entire opening 54a, it may be covered. In essence, it is good if the cover 53 can cover the area where the gas in the second region R2 flows toward the inkjet head 24.

The cover 53 has, for example, a main body 53b and a door portion 53c. The main body 53b is a U-shaped member that covers the space above the conveyance unit 21 and has a U-shaped appearance when viewed from the front side with the U-shaped opening facing downward. The main body 53b is connected to the partition member 54 so as to cover part or all of the opening 54a of the partition member 54 with the U-shaped opening facing downward. Therefore, the main body 53b has two sides perpendicular to the conveyance direction A1 and a ceiling connecting these two sides. The ceiling of the main body 53b is higher than the upper part of the inkjet head 24 when it is in the maximum raised position. Additionally, the ceiling of the main body 53b is at a position higher than the upper end of the inkjet head 24 at the maximum raised position by a height within the range of the lifting stroke of the inkjet head 24. The main body 53b is provided to fit tightly between the cover 23a and the cover 25a.

The door portion 53c is a door that can be opened and closed with respect to the main body 53b. The door portion 53c is, for example, box-shaped with one of the four sides missing. The door portion 53c is attached to the end of the main body 53b on the side opposite to the partition member 54 through a hinge (not shown), with the missing side facing the inkjet head 24. Additionally, the door portion 53c is provided to be detachable from the cover 25a. Therefore, in this embodiment, the cover 53 corresponds to a third cover that blocks the space above the conveyance unit 21 between the cover 23a and the cover 25a.

The door portion 53c is attached to the cover 25a while the tablet printing device 1 is operating. Additionally, when attaching/removing the inkjet head 24, the door portion 53c is removed from the cover 25a and moves toward the cover 23a through a hinge (not shown). Therefore, the inkjet head 24 can be attached and removed from the front side. Therefore, attachment and removal of the inkjet head 24 can be easily performed.

A ventilation portion 53a is formed on the surface of the cover 53 on the door 52 side (a surface parallel to the conveyance direction A1). The upper part of the ventilation portion 53a is at the same height as the ceiling of the main body 53b, but is several centimeters (cm) lower. Additionally, the ceiling of the main body 53b is at a position higher than the upper end of the inkjet head 24 at the maximum raised position by a height within the range of the lifting stroke of the inkjet head 24. As this ventilation portion 53a, for example, a mesh member such as a wire mesh or a punching member such as a punching plate is used. The ventilation unit 53a is for supplying the outside air received by the cooling unit 61 into the cover 53 from the ventilation unit 53a. A cooling portion 61 is provided on the surface of the cover 53 on the door 52 side to block the ventilation portion 53a. Additionally, the lower end of the ventilation portion 53a is preferably higher in the height direction than the upper part of the inkjet head 24 at its maximum raised position. If the lower end of the ventilation portion 53a is higher than the upper part of the inkjet head 24, the flow of cooling gas is not obstructed by the inkjet head 24. Therefore, the cooling gas from the cooling unit 61 easily flows into the second region R2. Additionally, in this case, it goes without saying that the upper end of the ventilation portion 53a is provided above the lower end of the ventilation portion 53a.

Within the case 51, there is a first region R1 and a second region R2 that continues (connects) to the first region R1. The conveyance unit 21 and each inkjet head 24 are provided in the first area R1, and the heat source 62 is provided in the second area R2. In addition, the moving mechanism 26 exists across the first area R1 and the second area R2, the maintenance unit 27 has a standby position in the second area R2, and the maintenance position is in the second area R2. 1 It exists in area (R1). In addition, the maintenance position of the maintenance unit 27 is a position where maintenance (purging, dummy discharge, wiping, etc.) of the inkjet head 24 is performed, and is a position below the inkjet head 24. The standby position of the maintenance unit 27 is the position of the maintenance unit 27 when maintenance of the inkjet head 24 is performed, and is a predetermined position in the second area R2 as shown in FIG. 3 . The maintenance unit 27 moves between the maintenance position and the standby position, that is, it moves in the left and right direction in FIG. 3 .

Here, the first area R1 is an area closer to the door 52 than the partition member 54 in the case 51. The second area R2 is an area closer to the heat source 62 than the partition member 54 in the case 51.

Each inkjet head 24 moves in the upward and downward direction (up and down direction in FIG. 3) by the movement mechanism 26, but the movement range Ha of the discharge surface in the upward and downward direction of each inkjet head 24 is It is a range between the normal position H1, which is normally located, and the maintenance position H2, where the maintenance unit 27 performs maintenance work on each inkjet head 24. The maintenance position H2 is a position where the maintenance unit 27 moves between the conveyance surface of the conveyance belt 21a and the discharge surface of each inkjet head 24 to perform maintenance work.

The cooling unit 61 receives outside air and sends it into the cover 53. As the cooling unit 61, for example, a cooling fan that creates an air flow is used, but it is not limited to this. The cooling unit 61 may be capable of supplying gas at a temperature lower than that of the second area R2 to at least the first area R1. For example, a supply unit that supplies compressed gas through a tube or the like may be used. . Additionally, as the gas, for example, gas such as air or nitrogen is used.

In addition, the cooling unit 61 is configured to operate the inkjet head 24 with respect to the heat source 62 in a direction intersecting the It is arranged to face each other with an in between. Specifically, the cooling unit 61 is provided at the end side of the direction in which each inkjet head 24 is arranged (Y direction). This is to allow the gas supplied by the cooling unit 61 to hit all of the inkjet heads 24.

Additionally, the cooling unit 61 supplies gas by ejecting it along a direction that intersects the transport direction A1 of the tablet T in a horizontal plane (for example, the Y direction, which is an orthogonal direction). Since the gas is supplied toward the second area R2 on the heat source 62 side, the inflow of air from the second area R2 on the heat source 62 side into the suction hole 21g may be prevented. When the amount of air flowing into the suction hole 21g from the second region R2 decreases due to the gas supplied from the cooling unit 61, the temperature of the air sucked into the suction hole 21g decreases, Furthermore, the temperature of the first region R1 also decreases. In addition, as the supply direction of the gas, for example, by providing the cooling unit 61 above the inkjet head 24, the gas may be supplied from above to below the inkjet head 24, and the suction hole 21g ), the direction of supply of the gas is not particularly limited as long as the temperature of the air flowing into the gas can be lowered.

In addition, the lower end of the cooling unit 61 is always higher than the discharge surface of each inkjet head 24 moving in the lifting direction, that is, the upper limit of the movement range Ha of the discharge surface of each inkjet head 24 in the lifting direction It is designed to be higher. That is, the cooling unit 61 is provided to eject gas while avoiding the discharge surface of the inkjet head 24 that moves by the moving mechanism 26.

This cooling unit 61 is electrically connected to the control device 40, and its operation is controlled by the control device 40. For example, the cooling unit 61 may be driven all the time while the device power is turned on, or may be driven only for a predetermined time or may be stopped only for a predetermined time. In addition, since the diffusion of heat by the heat source 62 is weak for a predetermined time from the start of tablet printing (e.g., a predetermined time for printing a predetermined number of tablets T), even if the cooling unit 61 is driven after the predetermined time has elapsed, good night. Additionally, a cooling unit 161 is provided on the second region R2 side of the case 51.

The cooling unit 161 receives air in the second region R2 and discharges it to the outside of the device. The cooling unit 161 is provided, for example, in a portion of the case 51 that separates the outside of the device from the second region R2. As the cooling unit 161, for example, a cooling fan is used. However, the cooling unit 161 is not limited to this. The cooling unit 161 may be a blower, pump, or the like. When the cooling unit 161 is a blower or pump, the cooling unit 161 is provided outside the device. And, the cooling unit 161 is connected to the portion of the case 51 that is in contact with the second region R2 through a pipe.

The heat source 62 is a source that generates heat. For example, the heat source 62 is a heat source related to one or both of the conveyance operation of the conveyance unit 21 and the printing operation of the inkjet head 24. Examples of this heat source 62 include a control board such as the control device 40, a blower used to suction and hold the tablets T, and a motor used to transport the tablets T.

(Configuration example of control device)

Next, a configuration example of the control device 40 will be described with reference to FIG. 8.

As shown in FIG. 8 , the control device 40 has an image processing unit 41, a storage unit 42, and a control unit 43. An input device 40a and an output device 40b are connected to this control device 40. The input device 40a is realized by, for example, a switch, a touch panel, a keyboard, or a mouse. Additionally, the output device 40b is realized by, for example, a display, a lamp, a meter, etc.

The image processing unit 41 receives the first image captured by the first imaging unit 23 and the second image captured by the second imaging unit 25, and processes the images using a known image processing technique. do. For example, the image processing unit 41 processes the first image obtained from the first imaging unit 23 to obtain the presence or absence of damage or foreign matter adhesion to the tablet T, and further Acquire the positions in the Y direction and the θ direction. Additionally, the image processing unit 41 processes the second image obtained from the second imaging unit 25 to obtain the printing position, shape, and size of the printing pattern (e.g., character or mark) printed on the tablet T. do. The image processing unit 41 provides information on the presence or absence of damage or adhesion of foreign matter to the acquired tablet T, position information in the X direction, Y direction, and θ direction of each acquired tablet T, and a print pattern on each tablet T. The printing position information, shape information, and size information are transmitted to the control unit 43.

The storage unit 42 stores processing information and various programs. For example, it is realized by semiconductor memory elements such as RAM (Random Access Memory) and flash memory, or storage devices such as hard disks and optical disks. The storage unit 42 stores print data related to printing, movement speed data of the conveyance belt 21a, and the like. Print data includes information on print patterns such as characters and marks.

The control unit 43 is, for example, a computer such as a CPU (Central Processing Unit), MCU (Micro Control Unit), or MPU (Micro Processing Unit), and controls each unit. For example, the control unit 43 operates the supply device 10, the printing device 20, the recovery device 30, the image processing unit 41, and the storage unit 42 based on various information and various programs stored in the storage unit 42. Controls unit 42, etc. Additionally, the control unit 43 receives detection signals, etc. transmitted from the position detector 21e and the detection unit 22 of the transfer unit 21, respectively. Additionally, the control unit 43 is realized by, for example, one or both of hardware and software.

(Movement of the inkjet head due to maintenance)

For example, the control unit 43 controls the moving mechanism 26 to move the discharge surface of each inkjet head 24 from the normal position H1 to the maintenance position H2 when performing maintenance work. When the discharge surface of each inkjet head 24 moves to the maintenance position H2, the control unit 43 moves the maintenance unit 27 to the maintenance position in the Y direction to control the discharge of each inkjet head 24. Maintain the surface. Additionally, as necessary, the maintenance unit 27 is moved to a position where the receiving plate 27b of the maintenance unit 27 faces the discharge surface of each inkjet head 24, and ink is supplied to each inkjet head 24. It is continuously discharged, and then the maintenance unit 27 is returned to its original position.

Here, the normal position H1, maintenance position H2, etc. are set in advance and stored, for example, in the storage unit 42. However, the normal position H1, maintenance position H2, etc. may be changed according to predetermined conditions or may be changed according to the user's input operation to the input device 40a.

(Movement of inkjet head due to abnormal tablet height)

Additionally, the control unit 43 determines whether the height of the tablet T on the conveyance belt 21a is abnormal based on the height information regarding the height of the tablet T detected by the detection unit 22 when tablet printing is performed. Determine whether or not. For example, when the height of the tablet T exceeds a predetermined threshold, the control unit 43 determines that the height of the tablet T on the conveyance belt 21a is abnormal. As shown in Fig. 9, the tablet with an abnormal height (hereinafter also referred to as “tablet with an abnormal height”) T is, for example, a tablet in a standing position. The tablet T in the standing position is in a state where the posture of the tablet T is vertical or inclined with respect to the conveyance surface of the conveyance belt 21a, and the inkjet head 24 is moved by the conveyance belt 21a in that posture. ), it collides with the inkjet head 24 whose discharge surface is located at the predetermined normal position H1. The tablet T may be held on the conveyance belt 21a in an upright position by the suction action of the suction hole 21g. In particular, when the holding surface of the tablet T has a round shape, one point rather than the central part of the tablet T may become a suction area, and the tablet T may be maintained in an upright position.

Additionally, the control unit 43 changes the conveyance speed at which the conveyance belt 21a conveys the tablets T based on whether the height of the tablets T on the conveyance belt 21a is abnormal. The gap between the conveyance surface of the belt 21a and the discharge surface of the inkjet head 24 is changed. For example, when the height of the tablet T on the transport belt 21a is abnormal, the control unit 43 controls the transport unit 21 to lower the transport speed of the transport belt 21a, and The moving mechanism 26 is controlled to widen the gap between the conveyance surface and the discharge surface of the inkjet head 24. Thereafter, the control unit 43 operates the movement mechanism 26 to return the inkjet head 24 to the normal position H1 when the tablet T with an abnormal height passes directly below the inkjet head 24. and controls the conveyance unit 21 to return the conveyance speed of the conveyance belt 21a to its original state.

More specifically, as shown in FIG. 9, the control unit 43 causes the inkjet head 24 to rise with respect to the tablet T whose height is abnormal, so that the discharge surface of the inkjet head 24 is adjusted to a predetermined normal level. The moving mechanism 26 is controlled to move from the position H1 to the predetermined retracted position H3. As a result, the gap between the conveyance surface of the conveyance belt 21a and the discharge surface of the inkjet head 24 widens. Even if the tablet T with an abnormal height reaches directly below the inkjet head 24 whose discharge surface is located at the predetermined retracted position H3 by the conveyance belt 21a in that state, It passes directly under the inkjet head 24 without colliding with the inkjet head 24. Thereafter, at the timing when the tablet T with an abnormal height passes directly below the inkjet head 24, the inkjet head 24 descends and the discharge surface of the inkjet head 24 moves to a predetermined retracted position (H3). The moving mechanism 26 is controlled to move from ) to the predetermined normal position H1. As a result, the gap between the conveyance surface of the conveyance belt 21a and the discharge surface of the inkjet head 24 returns to its original state.

Here, usually, the predetermined threshold value, the predetermined normal position H1, the predetermined retracted position H3, etc. are set in advance and stored, for example, in the storage unit 42. The normal position H1 is the lower limit of the movement range Ha of the discharge surface of the inkjet head 24, and the predetermined retraction position H3 is a position lower than the maintenance position H2, which is the upper limit of the movement range Ha. . However, the predetermined threshold, the predetermined normal position (H1), the predetermined retracted position (H3), etc. may be changed according to predetermined conditions or may be changed according to the user's input operation to the input device 40a. good night. The predetermined threshold value is set, for example, to the thickness of the tablet T + 1 mm. The distance between the printing surface of the tablet T and the discharge surface of the inkjet head 24 is usually about 1 mm, and the thickness of the tablet T is about 2 to 8 mm, so when the tablet T is 3 mm Considering this, when the height of the detected tablet T exceeds 4 mm, it exceeds the threshold value and is determined to be a tablet T with an abnormal height, causing the tablet T to collide with the inkjet head 24. It can be prevented. The predetermined normal position H1 is such that, for example, the inkjet head 24 does not collide with the tablet T in a lying state (normal posture) on the conveyance belt 21a and does not collide with the tablet T on the conveyance belt 21a. A position at which normal printing is possible (for example, a height position 1 mm away from the printing surface of the tablet T) is determined and set experimentally or theoretically. In addition, the predetermined retracted position H3 is a position where the inkjet head 24 does not contact the tablet T with an abnormal height on the conveyance belt 21a (for example, from the conveyance belt 21a to the tablet T ) is a height location away from the length diameter or more. Additionally, for either position, an appropriate margin is taken.

Additionally, the control unit 43 determines the The position of the direction is acquired, and based on the positional information indicating the position of the tablet T in the The second imaging timing of the imaging unit 25 is set, and timing information indicating these timings is generated and stored in the storage unit 42. The printing start timing is the timing at which printing is started for the tablet T that has reached the printing position immediately below the inkjet head 24. Additionally, the control unit 43 can acquire information such as the movement amount (rotation amount) and speed of the conveyance belt 21a based on the detection information transmitted from the position detector 21e.

Additionally, the control unit 43 controls the tablet T for which the presence/absence information has been obtained, based on information on the presence or absence of damage or foreign matter adhering to the tablet T transmitted from the image processing unit 41 (this information is information based on the first image). Print availability for (T) is set as print availability information. Then, the control unit 43 sets printing conditions as printing condition information for the tablet T set to be printable. At this time, the control unit 43 sets printing conditions for the tablet T for which the position information has been obtained, based on the position information of the tablet T in the Set it. For example, the control unit 43 determines the range of the nozzle 24a used for printing the target tablet T in the inkjet head 24 based on the Y-direction position information and print data of the tablet T, That is, the nozzle range to be used is determined, and printing conditions including the nozzle range to be used and the timing of printing start are set. In addition, when the tablet T has a directional shape, the control unit 43 sets printing conditions corresponding to the position of the tablet T in the θ direction based on the position information of the tablet T in the θ direction. do. As an example, the control unit 43 registers 180 print patterns in the storage unit 42 in which the direction of the print pattern is rotated by 1 degree in the range of 0 degrees to 179 degrees, and among these print patterns, the tablet (T) Set the printing conditions by selecting a printing pattern with an angle appropriate for the position in the θ direction.

Additionally, the control unit 43 based on the printing position information, shape information, and size information of the print pattern printed on the tablet T (these information is information based on the second image) transmitted from the image processing unit 41. Thus, it is determined whether the print pattern is printed in a predetermined shape and size at a predetermined position on the tablet T, that is, whether the print pattern is normally printed on the tablet T, and whether the printing quality of the tablet T is determined. Set information (check printing status). For example, in judging the shape and size of the print pattern, the control unit 43 registers the print pattern for inspection in the storage unit 42, and matches the print pattern for inspection on the tablet T after actual printing. Compare the print pattern (printed pattern on tablet (T)).

In addition, the control unit 43 appropriately controls various types of information (e.g., information on the presence or absence of damage or foreign matter adhering to the tablet T, position information, height information of the tablet T, timing information, print availability information, printing condition information, (print quality information, etc.) is stored in the storage unit 42, but when the target tablet T is recovered by the recovery device 30, for example, on the downstream side of the conveyance direction A1 in the conveyance unit 21. After falling from the end of , various information is deleted from the storage unit 42 when a predetermined time (e.g., several seconds) has elapsed. However, if this information is needed in a subsequent process, etc., it is possible to leave various information for each tablet T without erasing it, or to save it in a storage medium other than the device. When storing various information for each tablet (T), this information is combined with the date of manufacture, lot number, etc., and stored to prevent the investigation of the cause in the event of defective products occurring after shipment of the printed tablet (T). It is okay to allow it to be done.

(printing process)

Next, the printing process performed by the above-described tablet printing device 1 will be described with reference to FIG. 10. This printing process also includes an inspection process. Additionally, various types of information, such as data required for printing and data required for retraction of the inkjet head 24, are stored in advance in the storage unit 42.

As shown in FIG. 10, in step S1, when a large number of tablets T to be printed are fed into the hopper 11 of the supply device 10, the tablets T are transferred from the hopper 11 to the alignment feeder 12. It starts to be supplied sequentially and moves in a line by the sorting feeder 12. The tablets T moving in line are sequentially supplied to the conveyance belt 21a of the printing device 20 by the delivery feeder 13. The conveyance belt 21a is rotating in the conveyance direction A1 by rotation of the drive pulley 21b and each driven pulley 21c by the motor 21d. For this reason, the tablets T supplied on the conveyance belt 21a are lined up in a row on the conveyance belt 21a and are conveyed at a predetermined conveyance speed.

In step S2, the tablets T on the conveyance belt 21a are detected by the detection unit 22. In detail, the tablet T on the conveyance belt 21a is detected by the detection unit 22 at the timing when it reaches the detection position immediately below the detection unit 22 (e.g., the laser light irradiation position), and the tablet ( Based on the timing at which T) is detected, the position of the tablet T in the X direction on the conveyance belt 21a is recognized by the control unit 43. Then, position information indicating the position of the tablet T in the X direction is generated by the control unit 43 and stored in the storage unit 42. Additionally, the height of the tablet T on the conveyance belt 21a is detected by the detection unit 22, height information regarding the height of the tablet T is recognized by the control unit 43, and the tablet T The height information is stored in the storage unit 42.

In step S3, it is determined whether the height of the tablet T on the conveyance belt 21a is abnormal based on the height information. For example, it is determined whether the height of the tablet T on the conveyance belt 21a exceeds a predetermined threshold value. If it is determined that the height of the tablet T on the conveyance belt 21a exceeds a predetermined threshold, it is determined that the height of the tablet T on the conveyance belt 21a is abnormal (Yes in step S3), and the process proceeds to the following steps: Proceed to S11. On the other hand, if it is determined that the height of the tablet T on the conveyance belt 21a does not exceed a predetermined threshold, the height of the tablet T on the conveyance belt 21a is determined to be normal (No in step S3), and processing Proceeds to step S4.

In step S4, the tablet T on the conveyance belt 21a is imaged by the first imaging unit 23. In detail, the tablet T on the conveyance belt 21a is imaged by the first imaging unit 23 at the first imaging timing when it reaches the imaging position immediately below the first imaging unit 23, and the tablet T on the conveyance belt 21a is imaged by the first imaging unit 23. 1 The first image obtained by imaging by the imaging unit 23 is transmitted to the control device 40. Based on this first image, information on the presence or absence of damage or adhesion of foreign matter to the tablet T, as well as positional information in the X direction, Y direction, and θ direction of the tablet T are generated by the image processing unit 41, It is stored in the memory unit 42.

In step S5, the control unit 43 determines whether or not to print on the tablet T of interest based on information on whether the tablet T is damaged or has foreign matter attached thereto. If it is determined that printing on the target tablet T is possible (Yes in step S5), the process proceeds to step S6. In addition, based on information such as the positional information and printing pattern of the tablet T in the Printing conditions including printing start timing, etc. are set in the storage unit 42. Based on the above-described printing start timing (timing to start printing for the tablet T), the ejection timing for the tablet T (timing to eject ink for the tablet T) is determined. On the other hand, if it is determined that printing on the target tablet T is impossible (No in step S5), the process proceeds to step S9, and operations related to printing or inspection on the target tablet T are restricted. Additionally, the print availability information of the tablet T is appropriately stored in the storage unit 42. In addition, “restriction” on operations related to printing or inspection means not performing processing related to printing or inspection at least on the target tablet T.

In step S6, printing is performed by the inkjet head 24 based on the above printing conditions. That is, the inkjet head 24 is controlled by the control unit 43 to print a predetermined print pattern on the printable tablet T on the conveyance belt 21a. In detail, the printable tablet T on the conveyance belt 21a that has passed below the first imaging unit 23 is at the printing start timing when it reaches the printing position immediately below the inkjet head 24, as described above. It is printed by the inkjet head 24 based on certain printing conditions. In the inkjet head 24, ink is appropriately ejected from each nozzle 24a, and a printing pattern (e.g., number, alphabet, katakana, symbol, figure) is printed on the printing surface, which is the upper surface of the tablet T.

In step S7, the printed tablet T on the conveyance belt 21a is imaged by the second imaging unit 25. In detail, the printed tablet T on the conveyance belt 21a is imaged by the second imaging unit 25 at the second imaging timing when it reaches the imaging position immediately below the second imaging unit 25. , the second image obtained by imaging by the second imaging unit 25 is transmitted to the control device 40. This second image is processed by the image processing unit 41 of the control device 40. In detail, information about the printed print pattern printed on the tablet T, that is, the printing position, shape, and size of the printed print pattern, is acquired by the image processing unit 41. The second image transmitted from the second imaging unit 25 is processed by the image processing unit 41, and inspection information indicating the printing position, shape, and size of the printed pattern on the tablet T is generated, It is stored in the memory unit 42.

In step S8, a printing state inspection is performed by the control unit 43 based on the inspection information. In detail, the control unit 43 determines whether the print pattern has been properly printed on the tablet T based on the above-described inspection information regarding the printing position, shape, and size stored in the storage unit 42; , Print quality information indicating the print quality of the tablet T is generated and stored in the storage unit 42. For example, in the printing status inspection, the print pattern used for printing is stored in the storage unit 42 as a print pattern for inspection, non-defective product information regarding the predetermined printing position, shape, and size of the inspection print pattern, and the storage unit. The inspection information regarding the printing position, shape, and size of the actual printed print pattern stored in (42) is compared, and it is determined whether or not the print pattern was printed normally on the tablet T (pass or fail). .

In step S9, the tablets T on the conveyance belt 21a are recovered by the recovery device 30. Additionally, the ink applied to the tablet T is naturally dried during transportation and dried by the drying unit 28. In detail, when the recyclable tablets T reach the recyclable product collection section 31 as the conveying belt 21a moves, the tablets T are sprayed from above the tablets T by the spray nozzle 31a. The gas is sprayed, and the tablets T fall from the conveyance belt 21a and are received by the recovery box 31b. Likewise, when the defective tablets T reach the defective product recovery unit 32 as the transport belt 21a moves, gas is blown into the tablets T from above by the injection nozzle 32a. After being sprayed, the tablets T fall from the conveyance belt 21a and are received by the recovery box 32b. In addition, when the good quality tablet T reaches the position near the end of each driven pulley 21c side of the conveyance belt 21a, the suction effect does not work on the tablet T, and the injection nozzle 33a ), gas is sprayed onto the tablets T from above, and the tablets T fall from the conveyance belt 21a and are received in the recovery box 32b. Control regarding the spraying of such gas is executed by the control unit 43 based on various information such as, for example, position information of the tablet T, height information of the tablet T, print availability information, and print quality information.

In step S10, the control unit 43 determines whether printing has ended. For example, the number of tablets T that have been printed is counted, and when the number reaches a predetermined production number, it is determined that printing is complete. When it is determined that printing has ended (Yes in step S10), the process ends. On the other hand, if it is determined that printing has not ended (No in step S10), the process returns to step S1. In addition, regarding the determination of completion of printing, it may be determined that printing has ended according to the user's input operation on the input device 40a, for example, when the user presses the end printing button.

In step S3, if it is determined that the height of the tablet T on the conveyance belt 21a is abnormal (Yes in step S3), the conveyance speed of the conveyance belt 21a is adjusted by the control unit 43 in step S11. It comes down. For example, the conveyance speed may be lowered gradually or stepwise at a constant rate from a predetermined normal speed, or may be lowered gradually or stepwise at a random rate. The predetermined normal speed is reduced to a predetermined speed, and this predetermined speed is preferably a conveyance speed of about 1/10 of the normal speed.

For example, the predetermined speed is determined by the distance between the position immediately below the detection unit 22 on the conveyance belt 21a and the position immediately below the inkjet head 24 and the discharge surface of the inkjet head 24. It is determined based on the time required to move from the normal position H1 to the predetermined retracted position H3. In addition, the distance between the position immediately below the detection unit 22 on the conveyance belt 21a and the position immediately below the inkjet head 24 refers to, for example, the detection of tablets on the conveyance belt 21a by the detection unit 22. (T) is the distance between the detection position where it is detected and the position immediately below the upstream end of the conveyance direction A1 of the inkjet head 24.

In step S12, the inkjet head 24 is raised by the moving mechanism 26. For example, the inkjet head 24 rises until its discharge surface moves from the predetermined normal position H1 to the predetermined retracted position H3 (see Fig. 9). As a result, the gap between the conveyance surface of the conveyance belt 21a and the discharge surface of the inkjet head 24 widens to a predetermined retreat distance. This predetermined retreat interval is such that even if the tablet T with an abnormal height reaches directly below the inkjet head 24 by the conveyance belt 21a in that state, it will not collide with the inkjet head 24. The gap is such that it is possible to pass directly under the inkjet head 24 without any problems.

In step S13, the control unit 43 restricts printing of the tablet T with an abnormal height, that is, a plurality of tablets T located before and after the tablet T with an abnormal height. For example, the inkjet head 24 is raised by the moving mechanism 26 and stops ejecting. As a result, when the tablet T higher than the height and the tablet T transported before and after it (i.e., when the inkjet head 24 is positioned at a position higher than the normal position H1), it is positioned directly below the inkjet head 24. The passing tablets (T) are no longer printed by the inkjet head 24. As a result, the occurrence of tablets T with printing defects (failure to print) can be suppressed. That is, the control unit 43 stops printing by the inkjet head 24 on the tablet T at the same time that the inkjet head 24 is raised by the moving mechanism 26.

In step S14, the control unit 43 determines whether the tablet T of an abnormal height has passed directly under the inkjet head 24. If it is determined that the tablet T above the height has passed directly below the inkjet head 24 (Yes in step S14), the process proceeds to step S15. For example, when a predetermined time has passed since the tablet T on the conveyance belt 21a was detected by the detection unit 22, the control unit 43 detects the tablet T immediately below the inkjet head 24. It is determined that it has passed. Additionally, whether or not the tablet T above the height has passed directly below the inkjet head 24 may be determined by detection by the position detector 22e.

For example, the predetermined time is the transport speed (changing transport speed) of the tablet T, the position immediately below the detection unit 22 on the transport belt 21a, and the position directly below the inkjet head 24. is determined based on the distance of the position and the amount of movement (amount of rotation) of the conveyance belt 21a. In addition, the distance between the position immediately below the detection unit 22 on the conveyance belt 21a and the position immediately below the inkjet head 24 here refers to, for example, the distance between the position directly below the inkjet head 24 on the conveyance belt 21a by the detection unit 22. This is the distance between the detection position where the tablet T is detected and the position immediately below the downstream end of the inkjet head 24 in the conveyance direction A1.

In step S15, the inkjet head 24 is lowered by the moving mechanism 26. For example, the inkjet head 24 descends until its discharge surface moves from the predetermined retracted position H3 to the predetermined normal position H1 (see Fig. 9). As a result, the gap between the conveyance surface of the conveyance belt 21a and the discharge surface of the inkjet head 24 returns to the predetermined normal interval (the interval when the inkjet head 24 is located at the normal position H1). .

In step S16, the conveyance speed of the conveyance belt 21a is returned to the original by the control unit 43, and the process proceeds to step S9. For example, the conveyance speed may be increased gradually or stepwise at a constant rate up to a predetermined normal speed, or may be increased gradually or stepwise at a random rate. Additionally, a predetermined normal speed is set in advance and stored, for example, in the storage unit 42. However, the predetermined normal speed may be changed according to predetermined conditions, or may be changed according to the user's input operation to the input device 40a.

Even during this printing process, the cooling unit 61 (see FIG. 3) continues to receive external air and supply it to the first region R1. The temperature of the air supplied to the first region R1 is at least lower than the temperature in the second region R2. Air whose temperature is lower than the temperature within the second region R2 becomes cooling air. By supplying cooling air to the first region R1, the cooling air reaches each inkjet head 24, cooling each inkjet head 24, and cooling air flows through each inkjet head 24. Later, it flows into the suction hole 21g for holding the tablet T, making it difficult for the airflow from the heat source 62 side to be sucked into the suction hole 21g. Alternatively, the air from the heat source 62 side is cooled by cooling air and is sucked into the suction hole 21g. As a result, the temperature of the air flowing in near the suction hole 21g decreases, and the temperature near the inkjet head 24 further decreases.

Here, the target temperature near the inkjet head 24 is preferably, for example, 20 to 25 degrees. If cooling by the cooling unit 61 is not performed, the temperature near the inkjet head 24 exceeds 25 degrees. If the temperature near the inkjet head 24 exceeds 25 degrees, the possibility of problems occurring in the inkjet head 24 (such as a decrease in ink viscosity causing ejection defects) increases. Therefore, by lowering the temperature near the inkjet head 24 by supplying cooling air by the cooling unit 61, the viscosity of the ink in the inkjet head 24 decreases and the ink near the nozzle 24a decreases. Drying can be suppressed, making it possible to suppress the occurrence of ejection defects, and the occurrence of printing defects can be suppressed. Additionally, an increase in the temperature of the ink in the inkjet head 24 can be suppressed, making it possible to properly maintain the ink, and suppressing deterioration of the ink. Additionally, according to the experiment, it was confirmed that the temperature near the inkjet head 24 could be lowered from 28 to 31 degrees to about 23 degrees by supplying cooling air by the cooling unit 61.

In addition, a measuring instrument (not shown) is provided to measure the temperature near the inkjet head 24, and when the measurement result of this measuring instrument exceeds a predetermined temperature (for example, 24 degrees), the inkjet head 24 is supplied from the cooling unit 61. You may increase the amount of cooling air used. Alternatively, when the measurement result by the measuring device exceeds a predetermined temperature, printing by the inkjet head 24 may be stopped. By doing this, the occurrence of printing defects can be prevented. Additionally, a measuring device for measuring the temperature near the inkjet head 24 may be provided near the inkjet head 24, or may be provided on the inkjet head 24 itself to measure the surface temperature of the inkjet head 24 itself. You may do so. That is, the temperature near the inkjet head 24 also includes the temperature of the inkjet head 24 itself.

Additionally, the cooling unit 61 is designed to eject cooling air while avoiding the discharge surface of each inkjet head 24 moved by the moving mechanism 26. Accordingly, even if each inkjet head 24 is moved by the moving mechanism 26, such as when retreating from the tablet T or during maintenance, the cooling air blown out from the cooling unit 61 remains in the respective inkjet head 24. Since it does not directly contact the discharge surface of the ink, it is possible to prevent the ink near the nozzle 24a from drying and sticking. Therefore, it becomes possible to suppress the occurrence of ejection defects, and the occurrence of printing defects can be suppressed.

In addition, the air in the second region R2 is discharged to the outside of the device by the cooling unit 161, thereby creating a negative pressure in the second region R2. By creating a negative pressure in the second region R2, heat generated in the second region R2 is suppressed from flowing into the first region R1. Additionally, because the inside of the second region R2 becomes a negative pressure, the cooling gas from the cooling unit 61 easily flows into the second region R2.

Additionally, the length of the partition member 54 in the X direction is the same as the length of the conveyance unit 21 in the X direction. As a result, it is possible to prevent air in the second region R2 from flowing into the suction hole 21g on the conveyance belt 21a, which does not suction the tablet T. Additionally, the upper end of the partition member 54 is connected to the ceiling of the case 51. Warm air tends to go to the top of space. Accordingly, since the upper end of the partition member 54 is connected to the ceiling of the case 51, it is possible to prevent air warmed in the second region R2 from flowing into the first region R1.

In addition, the control unit 43 lowers the conveyance speed of the conveyance belt 21a in accordance with the detection of a height abnormality by the detection portion 22, and further controls the surface of the inkjet head 24 on the conveyance belt 21a side and the conveyance belt. The gap between the surfaces on the inkjet head 24 side at (21a) is widened. As a result, the tablet T with an abnormal height on the conveyance belt 21a can pass through the inkjet head 24 without colliding with it. Therefore, damage to the inkjet head 24 and breakage of the tablet T can be suppressed, thereby suppressing adverse effects due to an increase in the number of maintenance times, extension of the maintenance time, and breakage of the tablet T, thereby efficiently improving the tablet T. Printing can be performed on (T).

The control unit 43 raises the inkjet head 24, and as soon as the tablet T with an abnormal height passes directly below the inkjet head 24, the inkjet head 24 is moved to its original height position (normal position). (H1)), the conveyance speed of the conveyance belt 21a is returned to the normal speed, and printing at the normal conveyance speed is resumed. Only during the raising of the inkjet head 24, the passage of the tablet T above the height below the inkjet head 24, and the descent of the inkjet head 24, printing by the inkjet head 24 is stopped, and the inkjet head ( Since printing is performed when 24) is in the normal position H1, printing can be performed on the tablet T efficiently. In other words, printing cannot be performed on tablets following the above-height tablet T that exist at a distance equivalent to the length in the conveyance direction A1 of the inkjet head 24, but the inkjet tablet After completely passing the downstream end in the conveyance direction A1 of the head 24, printing can be resumed, and the tablets T that are higher than the height are conveyed and thus become non-printed tablets (T) are removed as much as possible. It can be suppressed. In addition, processing related to printing and inspection is restricted for subsequent tablets (T) of tablets (T) with an abnormal height, and these tablets (T) also become non-printed tablets.

The tablet T above the height and its subsequent tablets (tablets present at a distance equivalent to the length in the conveyance direction A1 of the inkjet head 24) pass through the inkjet head 24, As long as it returns to the normal position H1, the control unit 43 can resume printing on the tablet T by the inkjet head 24. If the conveyance speed of the conveyance belt 21a is lowered, printing may be resumed after returning the conveyance speed to the normal speed as described above, but printing is resumed with the conveyance speed lowered and the conveyance speed is increased while continuing printing. You may want to return it to its original state.

Here, usually, the supply speed at which tablets T are supplied from the supply device 10 to the conveyance unit 21 (the conveyance speed at which a feeder such as the alignment feeder 12 or the delivery feeder 13 conveys the tablets T) ) is always set to be slower than the conveyance speed at which the conveyance belt 21a conveys the tablets T. For this reason, when the control unit 43 lowers the conveyance speed of the conveyance belt 21a so as to maintain a predetermined speed difference between the supply speed of the supply device 10 and the conveyance speed of the conveyance belt 21a, the control unit 43 supplies The supply speed of the device 10 may also be reduced. Thereby, it is possible to suppress the tablets T from piling up in feeders such as the alignment feeder 12 and the delivery feeder 13.

Additionally, the control unit 43 may control the supply device 10 to stop supply of new tablets T as soon as it detects the tablets T with an abnormal height. As a result, tablets T with abnormal heights are generated, and new tablets T are not supplied on the conveyance belt 21a. The maintenance unit 27 of the inkjet head 24 enters between the inkjet head 24 and the conveyance belt 21a to perform maintenance. At this time, the inkjet head 24 retreats to a position higher than the normal position H1 to make space for the maintenance unit 27. For this reason, as soon as the tablets T on the conveyance belt 21a are recovered and new tablets T are not supplied to the conveyance belt 21a, maintenance work on the inkjet head 24 can be performed. Additionally, maintenance of the conveyance belt 21a (and suction hole 21g) may be performed at the timing of performing maintenance of the inkjet head 24.

In addition, the control unit 43 limits the ink ejection of the inkjet head 24 for the tablets T that passed directly under the detection unit 22 during the period of lowering the transport speed of the transport belt 21a, and transports the tablets T. The recovery device 30 may be controlled to recover the tablets T that passed directly under the detection unit 22 during the period when the conveyance speed of the belt 21a was lowered as reusable non-printed tablets, that is, as reusable products. As a result, the tablets T that passed directly under the detection unit 22 during the period when the conveyance speed of the conveyance belt 21a was lowered can be recovered as reuse products.

In addition, in order to change the distance between the placement surface of the conveyance belt 21a and the discharge surface of the inkjet head 24, the inkjet head 24 is moved by the moving mechanism 26, but is not limited to this and includes, for example, conveyance. The belt 21a may be moved by the moving mechanism 26. The movement of this conveyance belt 21a may be realized by moving the entire conveyance section 21 by the moving mechanism 26, or the part of the conveyance belt 21a opposing the inkjet head 24 may be moved. This may be realized by moving by the mechanism 26.

Here, when the conveyance object is a tablet (T), for example, compared to the case where the conveyance object is paper, the speed of passing under the inkjet head 24 is much faster, and also, the conveyance object and the inkjet head 24 The difference in relative size is large, and the transport interval between each transport object is also narrow. Therefore, it is not good to simply prevent collision between the conveyed object and the inkjet head 24, but it is also possible to prevent tablets that are affected, such as not being able to print, by retracting the inkjet head 24 to prevent collision (T ) becomes important to devise ways to reduce the number as much as possible. In addition, if the operation of the entire apparatus is stopped by detecting the tablets T with an abnormal height, and the tablets T on the conveyance belt 21a are recovered as unprinted (unprinted tablets), productivity significantly decreases. and throw it away Therefore, according to the present embodiment as described above, problems unique to tablets that are not present in printing on paper can be solved. In addition, in the case of printing on tablets T, unlike the case of printing on paper, one inkjet head 24 is used for a plurality of tablets T arranged in a direction perpendicular to the horizontal plane in the conveyance direction A1. ) may be used to print.

As described above, according to the embodiment, the tablet printing device 1 is provided in the first region R1, and includes a conveyance unit 21 that suctions and holds the tablet T in the suction hole 21g and conveys it; , an inkjet head 24 provided in the first area R1 and printing on the tablets T transported by the transport unit 21, and a second area R2 following the first area R1. It is provided with a heat source 62 provided in and a cooling unit 61 that supplies gas at a temperature lower than that of the second region R2 to the first region R1. As a result, it is possible to supply gas with a temperature lower than that of the second region R2 to the first region R1, thereby lowering the temperature near the inkjet head 24 in the first region R1. Therefore, it is possible to suppress the viscosity of the ink in the inkjet head 24 from decreasing and the ink near the nozzle 24a to dry, thereby suppressing the occurrence of ejection defects, thereby suppressing the occurrence of printing defects. . Additionally, an increase in the temperature of the ink within the inkjet head 24 can be suppressed, making it possible to properly maintain the ink, thereby suppressing deterioration of the ink.

<Other embodiments>

In the above description, printing is performed on the tablet T using the tablet printing device 1 (tablet printing method) according to one embodiment, but this is done using the tablet printing device 1 (tablet printing method) according to one embodiment. It can also be said in other words that printing is performed on the tablets (T) using a printing method to produce printed tablets (T). In other words, the tablet printing device 1 can be changed to a tablet manufacturing device, and the tablet printing method can be changed to a tablet manufacturing method.

In addition, in the above description, printing of one side of the tablet T is exemplified, but it is not limited to this. For example, the printing device 20 is set as one unit, and the units are arranged to overlap vertically, The tablets T printed by the upper printing device (first printing device) 20 are inverted and delivered to the lower printing device (second printing device) 20, and the tablets are printed by the lower printing device 20. By performing printing on (T), both sides of the tablet (T) may be printed.

In addition, in the above description, it is exemplified that the tablets (T) are transported in two rows, but this is not limited to this, and the number of rows may be in one row or in multiple rows of three or more rows, and is not particularly limited. The number of conveyance belts 21a may be two or more and is not particularly limited. Additionally, the number of inkjet heads 24 may be one or three or more, and is not particularly limited.

In addition, in the above description, the cover 53 is illustrated as being formed of the main body 53b and the door portion 53c, but is not limited thereto. For example, the side surface of the cover 23a on the inkjet head 24 side and the side surface of the cover 25a on the inkjet head 24 side may function as the side surface of the main body 53b. Additionally, the holding portion 51a of the case 51 may function as the ceiling of the main body 53b. Additionally, the ceiling of the cover 23a, cover 25a, and cover 53 may be integrated. Additionally, the cover 53 may be integral with the main body 53b and the door portion 53c without distinction.

In addition, in the above description, the cover 23a covering the first imaging unit 23 and the cover 25a covering the second imaging unit 25 are exemplified, but are not limited thereto. For example, the cover 23a and the cover 25a are not essential, and the cover 53 may be configured to surround at least the periphery and upper side of the inkjet head 24 on the conveyance unit 21.

In addition, in the above description, as for the opening 54a of the partition member 54, the shape of the opening 54a is notched, but it is not limited thereto. For example, in the case where there is no holding portion 51a, the opening 54a may be a hole wide enough to allow the maintenance portion 27 to pass between the first region R1 and the second region R2. . In this case, the lower end of the opening 54a is positioned at a height that allows the maintenance unit 27 to pass between the first area R1 and the second area R2. When the partition member 54 is connected to the ceiling of the case 51, the first area R1 and the second area R2 are substantially separated by the partition member 54. In this case, most of the heat generated in the second region R2 attempts to flow into the first region R1 through the opening 54a. However, since cooling gas is supplied from the cooling unit 61 to the space closed by the cover 53, the heat generated in the second region R2 is greatly suppressed from flowing into the first region R1. can do.

In addition, in the above description, a print head in which the nozzles 24a are arranged in a row is exemplified as the inkjet head 24, but it is not limited to this, and for example, a print head in which the nozzles 24a are arranged in a plurality of rows is exemplified. You may use it.

In addition, in the above description, it has been exemplified that the inkjet head 24 is provided so that the direction in which the nozzles 24a are arranged is perpendicular to the conveyance direction A1 in the horizontal plane, but this is not limited to this, and, for example, , it may be arranged so that the direction in which the nozzles 24a are arranged intersects the conveyance direction A1 in the horizontal plane.

In addition, in the above description, it has been said that the tablets T are supplied randomly rather than at regular intervals on the conveyance belt 21a, but the tablets are not limited to this and may be supplied at regular intervals. In addition, in the above description, it is said that the tablet T is suction-held by the suction hole 21g formed on the conveyance belt 21a, but the tablet T is not limited to this, and may be conveyed by being held in a pocket or the like. Alternatively, it may be carried by being held by its own weight on the transport belt 21a.

In addition, in the above description, the control unit 43 determines whether the height of the tablet T is abnormal based on the height information regarding the height of the tablet T detected by the detection unit 22. Although exemplified, it is not limited thereto. For example, based on the image of the tablet T obtained by the first imaging unit 23, the area, length, and shape of the tablet T supplied to the conveyance belt 21a when viewed in a plan view are detected (indirectly Height information may be obtained by detecting the height of the tablet (T). That is, when the area or length of the tablet T when viewed from the top is below the threshold, the height of the tablet T may be determined to be abnormal. Alternatively, based on the normal position H1 of the inkjet head 24, a position about 1 mm lower than the normal position H1 may be set as the threshold.

In addition, in the above description, when the tablet T with an abnormal height is detected by the detection unit 22, the control unit 43 sends the ink jet head 24 to the retracted position H3. It has been exemplified that printing is performed until the tablet moves to or until the tablet T is located one upstream of the tablet T, which is higher than the tablet T, but is not limited to this. For example, when the tablet T of an abnormal height is detected by the detection unit 22, printing by the inkjet head 24 may be stopped and moved from the normal position H1 to the retracted position H3. In this case, the conveyance speed of the conveyance belt 21a moves to the retracted position H3 after the tablet T with an abnormal height is detected until the tablet T with an abnormal height reaches the inkjet head 24. It is enough to reduce the speed to a level where it is possible. Alternatively, the inkjet head 24 is set to the retracted position (for example, about 10 tablets T, or the time at which it is predicted that about 10 tablets will be conveyed) so that the tablets T on which printing is limited are several tablets T before and after the tablet T with a height greater than or equal to the height. You may control it to move to H3). In this case, the speed difference before and after the reduction in the conveyance speed of the conveyance belt 21a becomes small, making it possible to increase the number of prints per unit time.

In addition, in the above description, it is exemplified that the conveyance speed of the conveyance belt 21a is gradually or stepwise lowered, but this is not limited to this, and the height of the tablet T is determined by the detection unit 22 at a predetermined threshold value. When it is detected that it has exceeded , the conveyance speed may be rapidly reduced to the target conveyance speed. When returning the conveyance speed of the conveyance belt 21a from the lowered speed to the normal speed, the conveyance speed may be restored gradually or stepwise, or may be returned rapidly, as in the case of lowering the conveyance speed. In either case, changing the conveyance speed gradually or stepwise can prevent the tablet T from being separated from the conveyance belt 21a.

Here, the above-mentioned tablets (T) may include tablets used for medicine, food, cleaning, industrial use, or fragrance use. In addition, tablets (T) include uncoated tablets, sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-coated tablets, multi-layer tablets, and press-coated tablets, and various capsule-sized tablets such as hard capsules and soft capsules (T). ) can be included. Additionally, the shape of the tablet T includes various shapes, such as disk, lens, triangle, and oval. Additionally, when the tablet T to be printed is for pharmaceutical or food use, an edible ink is suitable as the ink to be used. As this edible ink, any of synthetic dye ink, natural dye ink, dye ink, and pigment ink may be used.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and their equivalents.

1: Tablet printing device 10: Feeding device
11: Hopper 12: Sorting feeder
13: delivery feeder 20: printing device
21: conveyance unit 21a: conveyance belt
21b: driving pulley 21c: driven pulley
21d: motor 21e: position detector
21f: suction chamber 21g: suction hole
22: detection unit 23: first imaging unit
23a: Cover 24: Inkjet head
24a: nozzle 25: second imaging unit
25a: cover 26: moving mechanism
26a: Arm 26b: Arm moving mechanism
27: maintenance unit 27a: wiping unit
27b: receiving plate 28: drying unit
30: recovery device 31: reuse product recovery unit
31a: spray nozzle 31b: recovery box
32: defective product recovery unit 32a: spray nozzle
32b: Recovery box 33: Good product recovery unit
33b: recovery box 33a: injection nozzle
40: control device 40a: input device
40b: output device 41: image processing unit
42: memory unit 43: control unit
51: case 51a: maintenance part
52: Door 52a: Opening
53: Cover 53a: Ventilation part
53b: main body 53c: door part
54: partition member 54a: opening
54b: plate 54c: frame
55: door 61: cooling unit
62: heat source 161: cooling unit
A1: Conveyance direction A2: Conveyance direction
Ha: Movement range H1: Normal position
H2: Maintenance position H3: Retraction position
T: Tablet

Claims (12)

a transport unit provided in the first area to transport the tablet by suctioning it into the suction hole;
an inkjet head provided in the first area and printing on the tablet transported by the transport unit;
A heat source provided in a second area following the first area, and
A cooling unit that supplies gas at a temperature lower than that of the second area to the first area.
A tablet printing device comprising: The tablet printing device according to claim 1, wherein the heat source is a heat source related to one or both of the conveyance operation of the conveyance unit and the printing operation of the inkjet head. The tablet printing device according to claim 1, wherein the cooling unit is provided to face the heat source in a direction intersecting the transport direction of the tablet, with the inkjet head interposed therebetween. The tablet printing device according to claim 3, wherein the cooling unit ejects the gas in a direction intersecting the transport direction of the tablet in a horizontal plane. The method of claim 1, further comprising a moving mechanism that moves the conveyance unit or the inkjet head so as to change the distance between a surface of the inkjet head on the conveyance unit side and a surface of the conveyance unit on the inkjet head side,
The tablet printing device, wherein the cooling section is provided to eject the gas avoiding a surface on the side of the conveying section of the inkjet head moved by the moving mechanism. The method of claim 5, wherein the moving mechanism is provided in the second area,
A tablet printing device further comprising a partition member that is a wall for dividing the first area and the second area and has an opening for the movement mechanism to connect with the inkjet head. The method of claim 6, further comprising a cover having a ventilation portion provided with the cooling unit, attached to the partition member to cover part or all of the opening of the partition member, and blocking the space above the conveyance unit from the front side. tablet printing device. The method of claim 7, further comprising: a first imaging unit located upstream in the transport direction of the tablet from a position where the inkjet head is provided and provided above the transport unit;
a first cover that is non-contact with the conveyance unit and is provided to surround the first imaging unit;
a second imaging unit located downstream in the transport direction of the tablet from the position where the inkjet head is provided and provided above the transport unit;
A second cover that is non-contact with the transport unit and is provided to surround the second imaging unit.
It is further provided with,
The tablet printing device wherein the cover having the ventilation portion provided with the cooling portion is a third cover provided between the first cover and the second cover. The method of claim 8, wherein the cover having the ventilation portion provided with the cooling portion,
a main body that covers the space above the conveyance unit and has a U-shaped external appearance viewed from the front side with the U-shaped opening facing downward;
Door part that can be opened and closed with respect to the main body
Having a tablet printing device. The method of claim 5, comprising: a detection unit that detects height information of the tablet on the transport unit;
Control unit that controls the moving mechanism
It is further provided with,
The control unit controls the moving mechanism to widen the gap when the height of the tablet exceeds a predetermined threshold based on the height information detected by the detection unit. The method according to any one of claims 1 to 10, further comprising a maintenance unit provided in the second area and moving between the second area and the first area to perform maintenance work on the inkjet head. Tablet printing device. A transport unit provided in the first area holds the tablet by suction into the suction hole and transports it,
an inkjet head provided in the first area prints on the tablet transported by the transport unit, and
In a state where a heat source exists in a second area following the first area, the cooling unit supplies gas at a temperature lower than the temperature of the second area to the first area.
A tablet printing method comprising:

Images