Tablet printing device and tablet printing method

Abstract

To provide a tablet printing device and a tablet printing method capable of preventing ink transfer as much as possible and obtaining stable printing quality of tablets.SOLUTION: A tablet printing device 1 includes conveying devices 21, 31 that convey tablets T; inkjet printing heads 24, 34 that perform printing by discharging ink droplets onto the tablets T conveyed by the conveying devices 21, 31; a carry-out conveyor 43b that receives from the conveying devices 21, 31 and carries out the tablets T conveyed by the conveying devices 21, 31 and printed by the printing heads 24, 34; and a control device 50 that controls the carry-out conveyor 43b. The control device 50 performs control such that the density of the tablets T on the carry-out conveyor 43b becomes a predetermined value corresponding to the type of the tablets T, on the basis of the type of the tablets T.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Tablet printing devices that use an inkjet print head to print identification information such as letters and symbols on tablets are known. Such tablet printing devices align and transport multiple tablets using a transport device such as a transport conveyor, and eject ink (e.g., edible ink) from the nozzles of the inkjet print head toward the tablets being transported by the transport device, printing the identification information on each tablet. The printed tablets are transferred from the transport device to an output conveyor, and then collected from the output conveyor into a collection box. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-055177 Summary of the Invention [Problem to be solved by the invention]

[0004] Tablets can be broadly divided into two types. One is tablets that are not coated on the surface, such as plain tablets and OD (Orally Disintegrating) tablets (orally disintegrating tablets) (hereinafter referred to as "plain tablets"). The other is tablets that are coated on the surface, such as sugar-coated tablets, film-coated tablets, and enteric-coated tablets (hereinafter referred to as "coated tablets").

[0005] If these two types of tablets are printed in the same way using the tablet printing device described above, transfer may occur on the tablets stored in the collection box. Transfer may also occur even when a drying process such as blowing dry air on the discharge conveyor is performed. This type of transfer tends to occur more easily with coated tablets than with plain tablets. This is presumably because coated tablets are coated with sugars or water-soluble polymers, making it more difficult for ink to penetrate and dry than plain tablets.

[0006] Therefore, the inventors attempted to reduce the discharge speed of the discharge conveyor significantly below the conveying speed of the conveyor to ensure sufficient time for the ink to dry on the discharge conveyor before the tablets are collected in the collection box. However, this did not result in the suppression of transfer. Such transfer reduces the print quality of the tablets, and therefore it is desirable to minimize it.

[0007] The present invention aims to provide a tablet printing device and tablet printing method that can prevent ink transfer as much as possible and obtain stable printing quality for tablets. [Means for solving the problem]

[0008] The tablet printing apparatus according to the embodiment includes a supply device that stores a plurality of tablets and sequentially supplies the stored tablets; a conveying device that conveys the tablets supplied from the supplying device; an inkjet print head that ejects ink droplets onto the tablets being transported by the transport device to perform printing; an output conveyor that receives and outputs from the conveying device the tablets that have been conveyed by the conveying device and printed by the print head; a control device for controlling the discharge conveyor; Equipped with The control device controls the density of the tablets on the discharge conveyor based on the type of the tablets so that it becomes a predetermined value corresponding to the type of the tablets.

[0009] The tablet printing method according to the embodiment includes a supplying step of sequentially supplying tablets; a conveying step of sequentially conveying the supplied tablets; a printing step of printing on the tablets being conveyed by ejecting ink droplets from an inkjet print head; and a conveying step of conveying the tablets printed by the print head out by a conveying conveyor, In the discharge step, the discharge conveyor is driven based on the type of tablet so that the density of the tablets on the discharge conveyor becomes a predetermined value according to the type of tablet. [Effects of the Invention]

[0010] According to an embodiment of the present invention, stable printing quality of tablets can be obtained while preventing ink transfer as much as possible. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a front view showing a schematic configuration of a tablet printing apparatus according to a first embodiment. [Figure 2] 1 is a plan view showing a schematic configuration of a tablet printing apparatus according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] First Embodiment The first embodiment will be described with reference to FIGS.

[0013] (Example of tablet printing device configuration) As shown in Figures 1 and 2, the tablet printing device 1 according to the first embodiment includes a supply device 10, a first printing device 20, a second printing device 30, a collection device 40, and a control device (control unit) 50.

[0014] Of the components of the tablet printing apparatus 1, the supply device 10, the first printing device 20, the second printing device 30, and the recovery device 40 form a conveying path P for the tablets T in this order. A series of processes of supplying, printing, and recovering the tablets T are carried out on this conveying path P. Therefore, the upstream side of the conveying path P is the supply device 10 side, and the downstream side is the recovery device 40 side. In this embodiment, the conveying path P is formed in two rows. In this embodiment, an example will be described in which coated tablets are used as the tablets T.

[0015] The supply device 10 supplies tablets T to be printed to the first printing device 20 and has a hopper 11, an alignment feeder 12, and a delivery feeder 13. The hopper 11 stores a large number of tablets T and sequentially supplies the tablets T to the alignment feeder 12. The alignment feeder 12 aligns the supplied tablets T in two rows and transports them toward the delivery feeder 13. The delivery feeder 13 sequentially sucks in and holds the tablets T transported in two rows from the alignment feeder 12 from the upper side, transports the held tablets T in two rows to the upstream end of the first printing device 20, and delivers them to the first printing device 20. The portion of the alignment feeder 12 and the delivery feeder 13 where the tablets T are transported in two rows constitutes the transport path P. The supply device 10 is electrically connected to a control device 50, and its drive is controlled by the control device 50. The alignment feeder 12 and the delivery feeder 13 can be, for example, a belt transport mechanism such as a belt conveyor.

[0016] The first printing device 20 prints on the tablets T while transporting them, and is equipped with a transporting device 21, a detection device 22, a first imaging device (imaging device for printing) 23, a print head device 24, a second imaging device (imaging device for inspection) 25, and a drying device 26.

[0017] The conveying device 21 includes an endless conveying belt 21a, a driving pulley 21b, three driven pulleys 21c, a motor 21d, a position detector 21e, and a suction chamber 21f. The conveying belt 21a is mounted on the driving pulley 21b and the driven pulleys 21c, which are spaced apart at predetermined intervals. The driving pulley 21b is connected to the motor 21d. The motor 21d is electrically connected to the control device 50, and its drive is controlled by the control device 50. The position detector 21e is a device such as an encoder and is attached to the motor 21d. The position detector 21e is electrically connected to the control device 50 and transmits a detection signal to the control device 50. The control device 50 can obtain information such as the position, speed, and movement amount of the conveying belt 21a based on the detection signal. In this conveying device 21, the driving pulley 21b is rotated by the motor 21d to rotate the conveying belt 21a together with the driven pulleys 21c, and the tablets T on the conveying belt 21a are conveyed in the direction of the arrow A1 in FIG. 1 (conveying direction A1).

[0018] As shown in FIG. 2, the conveyor belt 21a has a plurality of circular suction holes 21g on its surface. These suction holes 21g are through-holes that adsorb tablets T onto the surface of the conveyor belt 21a, and are arranged in two rows along the conveying direction A1 to form two rows of conveying paths P. Each suction hole 21g is connected to the inside of the suction chamber 21f via a suction path formed in the suction chamber 21f, and is able to obtain suction force from the suction chamber 21f. A suction device such as a pump is connected to the suction chamber 21f via an suction pipe (neither is shown), and the inside of the suction chamber 21f can be depressurized. The suction device is controlled by the control device 50.

[0019] The detection device 22 has a plurality of detection units 22a (two in the example of FIG. 2). Each detection unit 22a is provided above the conveyor belt 21a, one for each conveying path P, so as to be aligned in a direction perpendicular to the conveying direction A1 on the horizontal plane, downstream in the conveying direction A1 from the position where the tablets T are supplied from the supply device 10 to the conveyor belt 21a. The detection unit 22a detects the position of the tablets T in the conveying direction A1 on the conveyor belt 21a by emitting and receiving laser light, and functions as a trigger sensor for each device located downstream. Each detection unit 22a is electrically connected to the control device 50 and transmits a detection signal to the control device 50.

[0020] The first imaging device 23 has a plurality of imaging units 23a (two in the example of FIG. 2). The imaging units 23a are provided above the conveyor belt 21a, one for each conveying path P, so as to be arranged downstream in the conveying direction A1 from the position where the detection device 22 is provided and in a direction perpendicular to the conveying direction A1 in the horizontal plane. Based on the position information of the tablet T described above, this imaging unit 23a captures an image when the tablet T arrives directly below the imaging unit 23a, obtains an image including the top surface of the tablet T (image for printing), and transmits the obtained image to the control device 50. Each imaging unit 23a is controlled by the control device 50.

[0021] The print head device 24 has a plurality of inkjet print heads 24a (two in the example of FIG. 2). The print heads 24a are provided downstream in the conveyance direction A1 from the position where the first imaging device 23 is provided, above the conveyor belt 21a, one for each conveyance path P, so as to be aligned in a direction perpendicular to the conveyance direction A1 in a horizontal plane. Each print head 24a has a plurality of nozzles 24b aligned, and is provided so that the direction in which the nozzles 24b are aligned intersects (for example, perpendicular to) the conveyance direction A1 in a horizontal plane. Each print head 24a is controlled by a control device 50.

[0022] The second imaging device 25 has a plurality of imaging units 25a (two in the example of FIG. 2). The imaging units 25a are provided downstream in the conveying direction A1 from the position where the print head device 24 is provided, and above the conveying belt 21a, one for each conveying path P, so as to be aligned in a direction perpendicular to the conveying direction A1 in the horizontal plane. Based on the position information of the tablet T described above, the imaging unit 25a captures an image when the tablet T arrives directly below the imaging unit 25a, obtains an image including the top surface of the tablet T (image for inspection), and transmits the obtained image to the control device 50. Each imaging unit 25a is controlled by the control device 50.

[0023] Returning to FIG. 1, the drying device 26 dries the ink applied to the tablets T and is provided downstream in the conveying direction A1 from the position where the print head device 24 is provided, for example, below the conveying device 21. This drying device 26 is used in common for the two rows of conveying paths P and is large enough to cover both rows of conveying paths P. As the drying device 26, various drying units can be used, such as a blower that dries using gas such as air, a heater that dries using radiant heat, or a blower that dries using warm or hot air using both gas and a heater. The drying device 26 is controlled by the control device 50.

[0024] The tablets T are transferred from the first printing device 20 to the upstream end of the second printing device 30 at a position downstream of the drying device 26, more specifically, at a position just before the conveying belt 21a reaches each driven pulley 21c.

[0025] The second printing device 30, like the first printing device 20, prints on tablets T while transporting them, and includes a transport device 31, a detection device 32, a first imaging device (imaging device for printing) 33, a print head device 34, a second imaging device (imaging device for inspection) 35, and a drying device 36. The transport device 31 includes a transport belt 31a, a drive pulley 31b, three driven pulleys 31c, a motor 31d, a position detector 31e, and a suction chamber 31f. Each component of the second printing device 30 has the same configuration as the corresponding component in the first printing device 20 described above, and therefore a description thereof will be omitted. However, the transport direction of the second printing device 30 is the direction of arrow A2 in FIG. 1 (transport direction A2), which is opposite to that of the second printing device 20.

[0026] The recovery device 40 recovers the tablets T by separating them into defective products, re-inspected products, and non-defective products, and includes a defective product recovery device 41, a re-inspected product recovery device 42, and a non-defective product recovery device 43. The recovery device 40 is provided downstream of the drying device 36 of the second printing device 30 in the conveying direction A2.

[0027] The defective product collecting device 41 has a plurality of spray nozzles 41a and collection boxes 41d. The spray nozzles 41a are provided for each transport path P, and one storage box 41d is provided in common for the two rows of transport paths P.

[0028] The injection nozzle 41a injects gas (e.g., air) toward a portion of the conveyor belt 31a where suction holes (similar to the suction holes 21g shown in FIG. 2) are provided, and the gas passes through the suction holes of the conveyor belt 31a and hits the tablets T adsorbed to the suction holes, causing the tablets T to drop from the conveyor belt 31a. The injection nozzle 41a is controlled by the control device 50.

[0029] The storage boxes 41d are provided directly below the injection nozzles 41a and below the conveying device 31. The storage boxes 41d store the tablets T dropped from the conveying belt 31a by the injection nozzles 41a.

[0030] The reinspection product recovery device 42 is provided at a position downstream of the drying device 36, and recovers the tablet T as an unknown product when a sensor (not shown) that detects the presence or absence of tablet T on the conveyor belt 31a detects that the tablet T is in a position not identified from the detection results of the detection devices 22 and 32. The reinspection product recovery device 42 has a shutter 42a, a motor 42b, a shutter detection unit 42c, and a recovery box 42d. The reinspection product recovery device 42 is provided downstream in the conveying direction A2 from the position where the defective product recovery device 41 is provided, and one shutter 42a and one recovery box 42d are provided in common to the two rows of conveying paths P.

[0031] The shutter 42a is provided at a position on the conveyor belt 31a just before it reaches the driven pulley 31c, more specifically, directly below the position where the tablet T is dropped from the conveyor belt 31a by the gas blowing section 43a described later. The shutter 42a is, for example, a rectangular plate member, and is formed so that the length in the width direction perpendicular to the conveying direction A1 is longer than the length in the direction along the conveying direction A1. Therefore, the width direction of the shutter 42a is the longitudinal direction. The width direction length of the shutter 42a is approximately the same as the width direction length of the conveyor belt 31a. The shutter 42a is provided so as to be swingable by a motor 42b, and the rotation shaft of the motor 42b is attached to the center of the shutter 42a in the short direction. In other words, the shutter 42a can swing around an axis in the horizontal direction perpendicular to the conveying direction A1. The motor 42b is a motor that can rotate forward and backward. The motor 42b is controlled by the control device 50. The shutter 42a also functions as a dispersing member, which will be described later. That is, the shutter 42a is also used as a part of the configuration of the non-defective product collecting device 43 for dispersing and transferring the tablets T on the discharge conveyor 43b of the non-defective product collecting device 43.

[0032] The shutter 42a can switch its position by a motor 42b between a state in which the tablets T are handed over to the non-defective product collecting device 43 (a state shown by a solid line in the figure) and a state in which the tablets T are handed over to a collection box 42d of the reinspection product collecting device 42 (a state rotated 90° counterclockwise from the state shown by the solid line in Fig. 1). Note that the state in which the shutter 42a hands over the tablets T to the non-defective product collecting device 43 is referred to as an open state, and the state in which the tablets T are handed over to the collection box 42d is referred to as a closed state.

[0033] The shutter detector 42c detects the stop position of the shutter 42a and detects whether the shutter 42a is in an open state or a closed state. The shutter 42a is normally maintained in an open state. For example, a rotary encoder is used as the shutter detector 42c. The shutter detector 42c transmits a detection signal to the control device 50.

[0034] The collection box 42d stores the tablets T passed from the shutter 42a.

[0035] The non-defective product recovery device 43 has a gas blowing section 43a, a carry-out conveyor 43b, a drying device 43c, and a recovery box 43d. The non-defective product recovery device 43 is provided downstream of the reinspection product recovery device 42 in the conveying direction A2, and one gas blowing section 43a, one drying device 43c, and one storage box 43d are provided in common for the two rows of conveying paths P.

[0036] The gas blowing section 43a is provided in the suction chamber 31f of the second printing device 30, at a position just before the conveyor belt 31a reaches the driven pulley 31c. During the printing process, the gas blowing section 43a constantly blows gas (e.g., air) toward the portion of the conveyor belt 31a where suction holes (similar to suction holes 21g) are formed. The gas blown out from the gas blowing section 43a passes through the suction holes of the conveyor belt 31a and hits the tablets T, causing the tablets T adsorbed to the suction holes to fall from the conveyor belt 31a. As the gas blowing section 43a, for example, an air blower having a slit-shaped opening extending in a direction perpendicular to the conveying direction A2 in a horizontal plane can be used. The gas blowing section 43a is controlled by the control device 50.

[0037] The output conveyor 43b receives the tablets T flowing in through the open shutter 42a and transports the received tablets T to the storage box 43d. Note that, for example, a belt conveyor can be used as the output conveyor 43b. The belt of this output conveyor 43b is an endless belt that is gas permeable. As the gas permeable belt, belts made of various materials with multiple through holes, such as mesh belts and belts with multiple round holes, can be used. The output conveyor 43b is controlled by the control device 50.

[0038] The drying device 43c has an upper drying section 43c1 and a lower drying section 43c2. This drying device 43c dries the tablets T on the discharge conveyor 43b using dry gas (e.g., dry air). The upper drying section 43c1 is provided above the discharge conveyor 43b and blows dry gas downward from above the discharge conveyor 43b. The lower drying section 43c2 is provided inside the discharge conveyor 43b and blows dry gas from inside the discharge conveyor 43b through the discharge conveyor 43b. These upper drying section 43c1 and lower drying section 43c2 are controlled by the control device 50. As the upper drying section 43c1 and the lower drying section 43c2, various drying sections can be used, such as a device that dries using dry gas, a blower that dries using gas such as air, a heater that dries using radiant heat, or a blower that dries using warm or hot air using both gas and a heater.

[0039] The collection box 43d is disposed at the downstream end of the discharge conveyor 43b. The storage box 43d receives and stores the tablets T from the discharge conveyor 43b.

[0040] The control device 50 includes an image processing unit 51, a print processing unit 52, an inspection processing unit (inspection unit) 53, and a memory unit 54. The image processing unit 51 processes images. The print processing unit 52 performs processing related to printing. The inspection processing unit 53 performs processing related to inspection. The memory unit 54 stores various information such as processing information and various programs. Such a control device 50 controls the supply device 10, the first printing device 20, the second printing device 30, and the collection device 40, and also receives position information of the tablets T transmitted from the individual detection devices 22 and 32 of the first printing device 20 and the second printing device 30, images transmitted from the individual imaging devices 23, 25, 33, and 35 of the first printing device 20 and the second printing device 30, and detection signals transmitted from the sensors 41b and 41c of the defective product collection device 41 of the collection device 40. The operating conditions are set in advance and stored in the memory unit 54. The control device 50 controls the defective product collection device 41 and the re-inspection product collection device 42 of the collection device 40 based on the operating conditions stored in the storage unit 54.

[0041] (Printing operation) Next, we will explain the printing operation performed by the tablet printing device 1. In the following printing operation, coated tablets are used as the tablets T, and double-sided printing will be explained in which identification information is printed on both sides of the tablets T. It is assumed that various information such as print data required for printing is stored in advance in the memory unit 54 of the control device 50.

[0042] First, when a large number of tablets T to be printed are placed into the hopper 11 of the supply device 10, the tablets T are sequentially supplied from the hopper 11 to the alignment feeder 12, where they are arranged in two rows and sent to the delivery feeder 13, after which they are supplied from the delivery feeder 13 to the conveyor belt 21a of the first printing device 20.

[0043] In the first printing device 20, the tablet T sucked and held on the conveyor belt 21a is detected by the detection device 22. As a result, the control device 50 acquires position information of the tablet T (position in the conveying direction A1). Based on this position information of the tablet T, the first imaging device 23 captures an image in synchronization with the timing at which the tablet T passes through the first imaging device 23, and based on the acquired image of the tablet T, positional deviation information of the tablet T is generated by the image processing unit 51 and stored in the memory unit 54.

[0044] Next, in synchronization with the timing at which the tablet T passes under the print head device 24, the print head device 24 prints the identification information on the tablet T based on the above-mentioned print data and printing conditions.

[0045] The tablet T on which the identification information is printed is imaged by the second imaging device 25 in time with the tablet T passing below the second imaging device 25. Based on the image captured by the second imaging device 25, the image processing unit 51 generates print pattern information and print position information of the identification information printed on the tablet T, and the inspection processing unit 53 determines whether the print quality, etc. is good or bad. In other words, it is determined whether the tablet T is good or bad.

[0046] After inspection, the tablets T are transported by the transport belt 21a, pass above the drying device 26 that is in a drying operation, and are then handed over to the second printing device 30. The ink printed on the tablets T is dried while passing above the drying device 26.

[0047] In the second printing device 30, the printing process is performed in the same manner as in the first printing device 20 described above. The tablets T that have passed through the second imaging device 35 are transported by the conveyor belt 31a, pass above the drying device 36 that is in a drying operation, and are dried. If the dried tablets T are judged to be defective, they are dropped from the underside of the conveyor belt 31a by the spray nozzle 41a and stored in a collection box 41d. If the tablets T are judged to be non-defective, they are dropped from the conveyor belt 31a by the gas blowing section 43a and handed over to the discharge conveyor 43b by the open shutter 42a. If the tablets T are judged to be non-defective by a sensor (not shown), the shutter 42a is temporarily switched to a closed state, and the tablets are stored in a collection box 42d.

[0048] The tablets T handed over to the discharge conveyor 43b are transported on the discharge conveyor 43b and pass through a space (drying space) between the upper drying section 43c1 and the lower drying section 43c2 of the drying device 43c that is in a drying operation. The tablets T that have passed through the drying space drop from the downstream end of the discharge conveyor 43b and are stored in a collection box 43d.

[0049] (Recovery of non-defective products) Next, the recovery operation of the non-defective product recovery device 43 will be described. In this embodiment, coated tablets, which are exemplified as tablets T to be printed on, generally have a lower ink penetration rate and are less likely to dry than plain tablets. Therefore, in this embodiment, the recovery operation of tablets T determined to be non-defective is performed by the control device 50 controlling the density of tablets T on the discharge conveyor 43b based on the type of tablet T so that it becomes a predetermined value corresponding to the type of tablet T. For example, the control device 50 controls the discharge conveyor 43b based on information related to the density of tablets T corresponding to the type of tablet T, which is stored in advance in the memory unit 54.

[0050] That is, the tablets T transferred from the conveyor belt 31a onto the discharge conveyor 43b via the shutter 42a are scattered randomly on the discharge conveyor 43b. The degree of scattering at this time mainly depends on the shape and size of the tablets. Specifically, when the shape and inclination angle of the shutter 42a and the conveying speed of the discharge conveyor 43b are the same, even if the shapes of the tablets T are the same (similar shapes), if the sizes are different, the degree of scattering will differ depending on the size. Furthermore, even if the sizes are roughly the same, if the shapes are different (for example, between tablets that are close to a cylinder and tablets that are close to an ellipse), the degree of scattering will also differ. The difference in the outer shape and size of the tablets T depends on the type. In other words, it can be said that the tablets T are scattered on the discharge conveyor 43b in a manner that depends on the type.

[0051] The degree of scattering of the tablets T on the discharge conveyor 43b can be said to be synonymous with the degree of congestion of the tablets T, and can therefore be seen as the density of the tablets T. When the density of the tablets T is high, the tablets T are more likely to come into contact with each other, and when the density is low, the tablets T are less likely to come into contact with each other. From this, it can be said that the density of the tablets T represents the ease with which the tablets T come into contact with each other. Furthermore, the ease with which the tablets T come into contact with each other leads to the ease with which ink transfer occurs. Therefore, by controlling the density of the tablets T on the discharge conveyor 43b, it is possible to prevent ink transfer on the discharge conveyor 43b. For this reason, by setting the density of the tablets T on the discharge conveyor 43b according to the type of tablets T so that ink transfer can be prevented, it is possible to ensure the maximum drying time while preventing ink transfer on the discharge conveyor 43b.

[0052] As described above, the degree of scattering of the tablets T on the discharge conveyor 43b depends on the type of tablets T, provided that the shape and inclination angle of the shutter 42a and the conveying speed of the discharge conveyor 43b are the same. Therefore, by changing the conveying speed of the discharge conveyor 43b, it is possible to change the degree of scattering of each type of tablets T, i.e., the density. That is, by increasing the conveying speed of the discharge conveyor 43b, the density of the tablets T can be reduced, and by decreasing the conveying speed, the density of the tablets T can be increased.

[0053] Therefore, in this embodiment, the conveying speed of the transport conveyor 43b that is within the range of density that can prevent transfer and that can ensure the longest drying time for the tablets T is set as information related to the density of the tablets T, depending on the type of tablet T. That is, information (for example, Table 1 below) that associates the type information of the tablets T with the conveying speed of the transport conveyor 43b corresponding to the type of tablet T is stored in advance in the memory unit 54. Then, when performing the printing operation of the tablets T, the control device 50 sets the speed corresponding to the type from the memory unit 54 as the conveying speed of the transport conveyor 43b based on the type information of the tablets T input to the control device 50.

[0054] Such a conveying speed can be determined, for example, by experiment. More specifically, the setting of the conveying speed of the transport conveyor 43b is switched for several hundred to several tens of thousands of tablets T as one unit, the state of ink transfer at each conveying speed is determined as a transfer rate, and the conveying speed at which the transfer rate is within an allowable range is set as the conveying speed suitable for that type of tablet T.

[0055] Table 1 shows the experimental results of determining the relationship between the density of tablets T on the conveyor 43b and the ink transfer rate by changing the conveying speed of the conveyor 43b using a certain type of coated tablet as a sample. Table 1 shows the transfer rate measured at 2% intervals for densities below 60% and above 100%, and at 10% intervals for densities between 60% and 100%. The conveying speeds at each density are also shown. Because the density is used as the reference, the amount of change in conveying speed is not necessarily constant. The number of tablets T processed (one unit) at each density was set to 10,000. The conveying speeds of tablets T by the conveying devices 21 and 31 of the first printing device 20 and the second printing device 30 were set to a speed that would result in a production (printing) number (processing rate) of 100,000 tablets per hour (since the conveying path P is two rows, this translates to 50,000 tablets per row per hour).

[0056] [Table 1]

[0057] From these results, it can be seen that, for example, if the allowable transfer rate for the tablet T is 16% or less, the conveying speed of the discharge conveyor 43b should be set to a speed that results in a density between approximately 70% and 90%.

[0058] Therefore, according to this embodiment, by performing the above-described control, it is possible to disperse the tablets T handed over from the conveying device 31 of the second printing device 30 onto the discharge conveyor 43b at a density that prevents ink transfer due to contact between the tablets T on the conveyor 43b. Furthermore, since the conveying speed of the conveyor 43b at this time is set to a speed that ensures as long a drying time as possible for the tablets T (ink), the ink printed on the tablets T can be dried to the maximum extent possible before the tablets T are stored in the collection box 43d. Therefore, it is possible to prevent ink transfer to the tablets T stored in the collection box 43d as much as possible, and stable printing quality of the tablets T can be obtained.

[0059] Depending on the type of tablet T (shape, size, etc.), it may be difficult for the tablets T to spread in a direction perpendicular to the conveying direction A1, i.e., in the width direction of the discharge conveyor 43b. For such types of tablets T, if the upper limit of the density at which transfer can be effectively prevented is relatively low, it may be difficult to ensure the drying time. That is, the drying time is determined by the conveying speed and length (conveying distance) of the discharge conveyor 43b, but the length of the discharge conveyor 43b is limited by the external dimensions of the tablet printing apparatus 1. Therefore, even if it becomes difficult to ensure the necessary drying time as a result of setting the conveying speed higher to lower the density, it is not possible to address this by extending the length of the discharge conveyor 43b. In such cases, it is advisable to use a shutter 42a as a dispersion member to widen the range in which the tablets T spread on the discharge conveyor 43b.

[0060] Tablets T that fall from the conveyor belt 31a of the second printing device 30 bounce off the shutter 42a and are transferred to the discharge conveyor 43b. Changing the tilt angle of the shutter 42a changes the contact position or angle of the tablet T with the shutter 42a, thereby changing the direction in which the tablet T bounces. Changing the direction of the bounce increases the chance that the tablet T will spread over a wider area. Therefore, during printing, the shutter 42a is controlled to swing within a predetermined angle range. For example, if the reference tilt angle of the shutter 42a in the open state (the tilt angle of the shutter 42a in the open state shown in FIG. 1) is 45°, it is recommended to swing the shutter 42a within a range of ±x° from 45°. Here, x is any angle that allows the tablet T to be delivered to the discharge conveyor 43b. Note that 45° (the reference angle) does not necessarily have to be the median value; different angles may be set for each.

[0061] Such swinging of the shutter 42a can be achieved using the motor 42b and the shutter detection unit 42c. That is, the above-mentioned reference tilt angle, swing range, and swing period (such as the time required for one swing and the rest time until the next swing) are stored in the memory unit 54, and the control device 50 controls the driving of the motor 42b so that the shutter swings within the stored swing range based on the detection value of the shutter detection unit 42c. That is, the density can be changed not only by the swing angle range but also by the swing period. The swing angle range and swing period that can obtain a desired density according to the tablet type can be determined, for example, by experiment.

[0062] By doing so, even tablets T that are difficult to spread on the discharge conveyor 43b when the inclination angle of the shutter 42a is fixed can be delivered so that they spread on the discharge conveyor 43b. As a result, even for such tablets T, ink transfer to the tablets T stored in the collection box 43d can be prevented as much as possible, and stable printing quality of the tablets T can be obtained.

[0063] Furthermore, instead of swinging the shutter 42a within a predetermined angle range, the surface of the shutter 42a (the surface from which the tablets T bounce) may be provided with irregularities, etc., to expand the range in which the tablets T are dispersed. That is, although the shutter 42a has been described as a plate member with a flat surface, it may also be provided with irregularities, such as sinusoidal waves, that continue in the width direction. For example, in the case of sinusoidal waves that continue in the width direction, when the position where the tablets T hit shifts in the width direction, the angle of the surface on which the tablets T hit changes. Therefore, it is considered that this easily produces an effect of spreading the tablets T in the width direction. A similar effect can be obtained not only with smooth sinusoidal waves, but also with sinusoidal waves that connect surfaces with different angles. It is preferable to determine the size and position of the irregularities according to the size of the tablets T. For example, if the tablet T is cylindrical and the distance between the peaks of the sine wave is greater than the diameter of the tablet T, and the slope of the sine wave is located directly below the suction holes of the conveyor belt 31a of the second printing device 30, the tablet T that falls from the conveyor belt 31a is more likely to bounce off only the slope on one side of one peak of the sinusoidal unevenness. In such a case, the tablet T will mainly bounce in the direction of the slope, making it difficult to achieve the effect of widening the range in which the tablet T is dispersed in the width direction. Therefore, in such a case, it is advisable to position the peak or the bottom of the valley directly below the suction holes of the conveyor belt 31a.

[0064] On the other hand, if the distance between the peaks is smaller than the diameter of the tablet T, even if the tablet T falling from the conveyor belt 31a mainly collides with the slope on one side of the peak, other parts of the tablet T, for example, the part located on the opposite side from the part that collided with the slope, may also collide with the top of the adjacent peak. Therefore, it is considered that the direction of rebound will be more irregular than when the tablet T collides only with the slope of the peak. Therefore, in such a case, it is considered that the effect of expanding the diffusion range of the tablet T can be obtained regardless of the positional relationship with the suction holes of the conveyor belt 31a. Therefore, it can be said that there is little need to consider the position.

[0065] Furthermore, if the unevenness has a continuous section with the same or similar inclination angle, it is thought that the rebound direction of the tablet T will also be similar within that range. Therefore, it is preferable that the inclination angle changes continuously, and it is preferable that the section with the same or similar inclination angle be as short as possible. For example, a surface that constitutes a sinusoidal unevenness may be further provided with fine sinusoidal unevenness.

[0066] Although an example of sinusoidal unevenness has been described, the unevenness does not need to have the same height between the convex and concave portions as in a sine wave. For example, the unevenness may be such that the height of the convex portions changes irregularly or regularly, or such that the height of the concave portions changes irregularly or regularly, or a combination thereof. Of course, the unevenness is not limited to a sinusoidal wave, and any unevenness other than the above may be used as long as it can expand the diffusion of the tablets T on the discharge conveyor 43b compared to when the surface of the shutter 42a is flat.

[0067] The configuration of the discharge conveyor 43b is not particularly limited. For example, one wide discharge conveyor 43b may be provided for two (multiple) rows of transport paths P, or one discharge conveyor 43b may be provided for each transport path P.

[0068] The density of tablets T on the discharge conveyor 43b can be calculated by the amount of tablets T per unit area (number of tablets T x projected area of ​​tablets T in a plan view), but it is preferable to set the unit area within the range in which tablets T are distributed on the discharge conveyor 43b. For example, if the width of the discharge conveyor 43b is 100 mm and the range in which tablets T are distributed in the width direction on the discharge conveyor 43b is 50 mm, if the density is calculated using the entire width (100 mm) of the discharge conveyor 43b as the width direction length of the unit area, the value will be smaller than the actual density. If the conveying speed of the discharge conveyor 43b is set based on the density calculated in this way, it may result in a density at which ink transfer is likely to occur. Therefore, it is preferable to calculate the density of tablets T based on the distribution of tablets T.

[0069] The tablet printing apparatus 1 may be used to produce tablets T. In such cases, a throughput may be set (e.g., 100,000 tablets per hour, 150,000 tablets per hour, etc.). This throughput may restrict the conveying speed of the discharge conveyor 43b and the density of the tablets T. For example, suppose the processing rate for the tablet T varieties corresponding to Table 1 is changed from 100,000 tablets per hour to 120,000 tablets per hour. In this case, the number of tablets T delivered per unit time to the discharge conveyor 43b increases by 1.2 times. Therefore, if the conveying speed of the discharge conveyor 43b remains the same, the desired density cannot be obtained. Increasing the conveying speed of the discharge conveyor 43b, for example, by 1.2 times, may achieve the desired density. However, the increased conveying speed shortens the time required for the tablets T to pass over the discharge conveyor 43b, i.e., the drying time. This may increase the transfer rate. Therefore, when changing the processing amount, it is preferable to reacquire information that associates the type information of the tablets T with the transport speed of the transport conveyor 43b (density of the tablets T) according to the type of the tablets T.

[0070] Furthermore, even if the processing volume is the same, if the size of the tablets T changes, the conveying speed of the tablets T by the conveying devices 21 and 31 of the first printing device 20 and the second printing device 30 may change. In such cases, not only the number of tablets T delivered per unit time onto the discharge conveyor 43b but also the area occupied by one tablet T on the discharge conveyor 43b changes. Therefore, in such cases, it is preferable to re-acquire information that associates the type information of the tablets T with the conveying speed of the conveyor 43b (density of the tablets T) according to the type of the tablets T.

[0071] <Other embodiments> In the above explanation, an example was given in which one print head 24a, 34a is provided for each of two rows of transport paths P, but it is also possible to provide one print head for multiple transport paths P, or to provide three or more print heads for each transport path P.

[0072] Also, an example has been described in which the shutter 42a as a dispersion member is swung around an axis along the horizontal direction perpendicular to the conveying direction. However, if the dispersion member is not also used as the shutter 42a that distributes the tablets T between the non-defective product recovery device 43 and the reinspection product recovery device 42 but is provided as a dedicated member, it is not necessarily required to swung around an axis along the horizontal direction perpendicular to the conveying direction.

[0073] Furthermore, the dispersion member is not limited to a plate-shaped member, and may be of any configuration as long as it can widen the range in which the tablets T are dispersed on the discharge conveyor 43b.

[0074] Here, the aforementioned tablets T can include tablets used for pharmaceutical, edible, cleaning, industrial, or aromatic purposes. Tablets T include plain tablets (plain tablets), sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-coated tablets, multilayer tablets, and dry-coated tablets. Tablets T can also include tablets equivalent to coated tablets, and various capsule tablets such as hard capsules and soft capsules. Tablets T can have various shapes, such as discs, lenses, triangles, and ellipses, and any of these shapes can be included. When the tablet T to be printed is for pharmaceutical or edible use, edible ink is preferably used. As the edible ink, any of synthetic pigment ink, natural pigment ink, dye ink, and pigment ink may be used.

[0075] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0076] 1. Tablet printing equipment 10 Feeding device 20 First printing device 21 Conveyor equipment 21a Conveyor belt 30 Second printing device 31 Transport device 31a Conveyor belt 40 Recovery Device 42a Shutter (member) 42b Motor 42c Shutter detection unit 43 Good product recovery device 43b Discharge Conveyor 43c drying equipment 43c1 Upper drying section 43c2 Lower drying section 43d Collection Box 50 Control device T tablets

Claims

1. a supply device that stores a plurality of tablets and sequentially supplies the stored tablets; a conveying device that conveys the tablets supplied from the supplying device; an inkjet print head that ejects ink droplets onto the tablets being transported by the transport device to perform printing; an output conveyor that receives and outputs from the conveying device the tablets that have been conveyed by the conveying device and printed by the print head; a control device for controlling the discharge conveyor; Equipped with The control device controls the density of the tablets on the discharge conveyor based on the type of tablet so that it becomes a predetermined value corresponding to the type of tablet.

2. The tablet printing apparatus according to claim 1 , wherein the control device controls the density to be the predetermined value by controlling a conveying speed of the discharge conveyor.

3. The tablet printing device according to claim 2 , wherein the control device stores information on the conveying speed for each type of tablet.

4. The tablet printing apparatus according to any one of claims 1 to 3, further comprising a dispersing member for dispersing tablets from the conveying device onto the discharge conveyor.

5. The dispersion member includes a plate member provided corresponding to a transfer position of the tablets from the conveying device to the discharge conveyor, and a drive unit that swings the plate member about an axis in a direction intersecting the conveying direction of the discharge conveyor, The control device swings the plate member at a predetermined cycle based on the conveying speed. The tablet printing device according to claim 4.

6. a supply step of sequentially supplying tablets; a conveying step of sequentially conveying the supplied tablets; a printing step of printing on the tablets being conveyed by ejecting ink droplets from an inkjet print head; and a conveying step of conveying the tablets printed by the print head out by a conveying conveyor, In the discharge process, the tablet printing method drives the discharge conveyor based on the type of tablet so that the density of the tablets on the discharge conveyor becomes a predetermined value corresponding to the type of tablet.

Images