JP2018130536A - Tablet printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tablet printing device capable of inhibiting a deterioration in printing quality.SOLUTION: A tablet printing device according to an embodiment includes: a conveyor belt 21a which has a suction hole connected to a suction chamber 21f and which conveys a tablet T by sucking the tablet into the suction hole; a print head 24a which has a nozzle surface M1 formed with a nozzle, which has the nozzle surface M1 provided above the conveyor belt 21a in the state of being directed toward the conveyor belt 21a, and which employs an inkjet method for performing printing on the tablet T conveyed by the conveyor belt 21a; and a control plate 27 which is positioned on an upstream side in a conveyance direction A1 of the tablet T with respect to the print head 24a, which is provided between the conveyor belt 21a and a height position of the nozzle surface M1 of the print head 24a, and which controls an air current generated between the conveyor belt 21a and the print head 24a.SELECTED DRAWING: Figure 3

Description

  Embodiments described herein relate generally to a tablet printing apparatus.

  In order to print identification information such as characters and marks on a tablet, a technique for performing printing using an ink jet type print head is known. A tablet printing apparatus using this technology conveys tablets by a tablet conveying device such as a conveyor, and ink is directed from a nozzle of an ink jet printing head disposed above the tablet conveying device toward a tablet passing under the printing head. (For example, edible ink) is discharged, and identification information is printed on the tablet. As a tablet conveying device, a tablet conveying device that sucks and holds a tablet on a conveying belt has been developed. In order to suck and hold tablets, a plurality of, for example, circular or rectangular suction holes are formed on the transport belt of the suction type tablet transport device so as to be aligned in the tablet transport direction.

  In the transport belt of the suction type tablet transport device described above, the tablet supplied onto the suction hole is held on the transport belt by suction from the suction hole. However, the suction hole may not be completely blocked by the tablet. Depending on the size, shape, posture, etc. of the tablet, a state where a part of the suction hole is not blocked or a state where the suction hole is not blocked at all by random supply of the tablet occurs. When the suction hole is not completely blocked by the tablet, air is sucked from the suction hole, so that an air flow is generated above the suction hole. Further, when the tablets are transported, the surface of the transport belt is moved along the transport direction of the tablets, so that an air flow flowing on the transport belt along the transport direction of the tablets is also generated by the movement of the transport belt. Such various air currents are mixed to generate turbulent air currents. Further, when the print head and its peripheral members are present above the conveyance belt, the airflow flowing on the conveyance belt collides with these members and further turbulence is generated.

  When air current such as turbulence is generated below or around the print head, the tablet powder adhering to the tablet or the conveyor belt may fly and adhere to the nozzle surface (surface on which the nozzle is formed) of the print head. . If tablet powder adheres to the nozzle surface, the nozzle will clog and cause ejection failure, or the ink ejected from the nozzle will not fly normally and land on places other than the desired position on the tablet, Print quality may be reduced.

  In addition, when an air current such as turbulence is generated below or around the print head, the tablet sucked and held by the conveyor belt is shaken by the turbulence when the tablet passes below the print head, and the orientation of the tablet printing surface May not be maintained. If the posture of the tablet printing surface cannot be maintained, the ink may land on a portion other than the desired position on the tablet, and the print quality may deteriorate.

JP-A-7-081050

  The problem to be solved by the present invention is to provide a tablet printing apparatus capable of suppressing a decrease in print quality.

  A tablet printing apparatus according to an embodiment of the present invention has a suction hole connected to a suction chamber, a transport belt that sucks and transports the tablet to the suction hole, and a nozzle surface on which a nozzle is formed, An ink jet print head that has a nozzle surface facing the transport belt and is provided above the transport belt, and performs printing on tablets transported by the transport belt, and is positioned upstream of the print head in the transport direction of the tablets. And a control plate for controlling an air flow generated between the conveyor belt and the print head.

  According to the embodiment of the present invention, it is possible to suppress a decrease in print quality.

It is a figure which shows schematic structure of the tablet printing apparatus which concerns on 1st Embodiment. FIG. 3 is a plan view showing a part of the first printing apparatus according to the first embodiment. It is a figure which shows a part of 1st printing apparatus which concerns on 1st Embodiment. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a figure which shows the comparison result of the tablet printer which concerns on 1st Embodiment, and another tablet printer. It is a figure which shows a part of 1st printing apparatus which concerns on 2nd Embodiment. It is a figure which shows a part of 1st printing apparatus which concerns on 3rd Embodiment. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. It is a figure which shows the control board which concerns on 4th Embodiment. It is a figure which shows the control board which concerns on 5th Embodiment. It is a figure which shows the modification of the control board which concerns on 5th Embodiment. It is a figure which shows the control board which concerns on 6th Embodiment. It is a figure which shows the control board which concerns on 7th Embodiment.

<First Embodiment>
A first embodiment will be described with reference to FIGS. 1 to 5.

(Basic configuration)
As shown in FIG. 1, the tablet printing apparatus 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 50. It has. The first printing device 20 and the second printing device 30 have basically the same structure.

  The supply device 10 includes a hopper 11, an alignment feeder 12, and a delivery feeder 13. The supply device 10 is configured to be able to supply the tablet T to be printed to the first printing device 20, and is positioned on one end side of the first printing device 20. The hopper 11 accommodates 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 conveys them toward the delivery feeder 13. The delivery feeder 13 sequentially sucks the tablets T on the alignment feeder 12 and conveys them to the first printing device 20 in two rows, and supplies the first printing device 20 with two rows. The supply device 10 is electrically connected to the control device 50, and its driving is controlled by the control device 50. As the alignment feeder 12 and the delivery feeder 13, for example, a belt conveyance mechanism can be used. The tablet T to be printed has a three-dimensional shape and a thickness.

  The first printing apparatus 20 includes a conveyance apparatus (tablet conveyance apparatus) 21, a detection apparatus 22, a first imaging apparatus (imaging apparatus for printing) 23, a print head apparatus 24, and a second imaging apparatus ( An imaging device for inspection) 25 and a drying device 26.

  The transport device 21 includes a transport belt 21a, a pulley body 21b that is a drive pulley, a plurality of (three in the example of FIG. 1) driven pulleys 21c, a motor (drive unit) 21d, a position detector 21e, and a suction chamber 21f. doing. The conveyor belt 21a is formed in an endless shape, and is stretched over the pulley body 21b and each driven pulley 21c. The pulley body 21b and each driven pulley 21c are rotatably provided in the apparatus main body, and the pulley body 21b is connected to a motor 21d. The motor 21 d is electrically connected to the control device 50, and its driving 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 21 e is electrically connected to the control device 50 and transmits a detection signal to the control device 50. Based on the detection signal, the control device 50 can obtain information such as the position, speed, and amount of movement of the conveyor belt 21a. The transport device 21 rotates the transport belt 21a together with each driven pulley 21c by the rotation of the pulley body 21b by the motor 21d, and the tablet T on the transport belt 21a is moved in the direction of the arrow A1 in FIG. 1 and FIG. Transport to A1).

  Here, as shown in FIG. 2, a plurality of circular suction holes 21g are formed on the surface of the conveyor belt 21a. These suction holes 21g are through-holes that adsorb the tablets T, and are arranged in two rows in parallel along the transport direction A1 so as to form two transport paths. Each suction hole 21g is connected to a suction chamber 21f (see FIG. 1), and a suction force can be obtained by the suction chamber 21f. The suction chamber 21f is a chamber for applying (acting) a suction force to the tablet T placed in each suction hole 21g of the transport belt 21a. An intake device such as a pump is connected to the suction chamber 21f via a suction pipe (both not shown), and the inside of the suction chamber 21f is decompressed by the operation of the intake device. The suction tube is connected to the approximate center of the side surface (surface parallel to the transport direction A1) of the suction chamber 21f. Further, the intake device is electrically connected to the control device 50, and the driving thereof is controlled by the control device 50.

  The detection device 22 has a plurality of detection units 22a (two in the example of FIG. 2). The detection part 22a is a tablet in the direction (for example, orthogonal direction) which is downstream of the conveyance direction A1 and intersects the conveyance direction A1 in the horizontal plane with respect to the position where the supply device 10 supplies the tablets T on the conveyance belt 21a. One for each of the T transport paths and arranged above the transport belt 21a. The detection unit 22a detects the position of the tablet T on the transport belt 21a (position in the transport direction A1) by projecting and receiving laser light, and functions as a trigger sensor for each device located downstream. As the detection unit 22a, various laser sensors such as a reflective laser sensor can be used. Each detection unit 22 a is electrically connected to the control device 50 and transmits a detection signal to the control device 50.

  The first imaging device 23 includes a plurality of imaging units 23a (two in the example of FIG. 2). One image pickup unit 23a is provided downstream of the position where the detection device 22 is provided in the transport direction A1 and intersects the transport direction A1 in a horizontal plane (for example, a direction orthogonal to each other) for each transport path of the tablets T. They are arranged one by one and are provided above the conveyor belt 21a. Based on the position information of the tablet T described above, the imaging unit 23a performs imaging at the timing when the tablet T arrives directly below the imaging unit 23a, and acquires an image including the upper surface of the tablet T (image for printing). The acquired image is transmitted to the control device 50. As the imaging unit 23a, various cameras having an imaging element such as a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor) can be used. Each imaging unit 23 a is electrically connected to the control device 50, and their driving is controlled by the control device 50. Note that illumination for imaging is also provided as necessary.

  The print head device 24 has a plurality of inkjet print heads 24a (two in the example of FIG. 2). The print head 24a is downstream of the transport direction A1 from the position where the first imaging device 23 is provided, and is in the direction intersecting the transport direction A1 in the horizontal plane (for example, the orthogonal direction) for each transport path of the tablets T. One by one and provided above the conveyor belt 21a. The print head 24a includes a plurality of nozzles 24b (see FIG. 2; however, only four are shown in the drawing), and individually ejects ink from these nozzles 24b. In the print head 24a, the surface on which the nozzles 24b are formed is the nozzle surface M1 (see FIG. 1). The print head 24a is provided such that the alignment direction in which the nozzles 24b are arranged intersects the transport direction A1 in a horizontal plane (for example, to be orthogonal). As the print head 24a, it is possible to use various ink jet type print heads having driving elements such as piezoelectric elements, heating elements or magnetostrictive elements. Each print head 24 a is electrically connected to the control device 50, and their drive is controlled by the control device 50.

  The second imaging device 25 has a plurality of imaging units 25a (two in the example of FIG. 2). The imaging unit 25a is provided downstream of the position where the print head device 24 is provided in the transport direction A1 and in a direction intersecting the transport direction A1 in the horizontal plane (for example, a direction orthogonal to each other) for each transport path of the tablets T. They are arranged one by one and are provided above the conveyor belt 21a. Based on the position information of the tablet T described above, the imaging unit 25a performs imaging at the timing when the tablet T arrives directly below the imaging unit 25a, and acquires an image including the upper surface of the tablet T (an image for inspection). The acquired image is transmitted to the control device 50. As the imaging unit 25a, various cameras having an imaging element such as a CCD or a CMOS can be used as in the above-described imaging unit 23a. Each imaging unit 25 a is electrically connected to the control device 50, and their driving is controlled by the control device 50. Note that illumination for imaging is also provided as necessary.

  Returning to FIG. 1, the drying device 26 is positioned on the downstream side in the transport direction A1 from the position where the second imaging device 25 is provided, and is provided, for example, below the transport device 21. The drying device 26 is a drying device common to the two rows of transport paths, and dries the ink applied to each tablet T on the transport belt 21a. As the drying device 26, it is possible to use various drying units such as a heater that dries the object to be dried by radiant heat, or a blower that dries the object to be dried by hot air or hot air. The drying device 26 is electrically connected to the control device 50, and its driving is controlled by the control device 50.

  Note that the tablet T that has passed above the drying device 26 is transported along with the movement of the transport belt 21a, and reaches a position in the transport belt 21a near the end of each driven pulley 21c. At this position, the suction action does not act on the tablet T, and the tablet T is released from the state held by the transport belt 21 a and is transferred from the first printing device 20 to the second printing device 30.

  The second printing device 30 includes a transport device 31, a detection device 32, a first imaging device (printing imaging device) 33, a print head device 34, and a second imaging device (inspection imaging device). ) 35 and a drying device 36. The transport device 31 includes a transport belt 31a, a pulley body 31b that is a drive pulley, a plurality of (three in the example of FIG. 1) driven pulleys 31c, a motor (drive unit) 31d, a position detector 31e, and a suction chamber 31f. doing. Note that each element constituting the second printing apparatus 30 has basically the same structure as the corresponding component of the first printing apparatus 20 described above, and therefore description thereof is omitted. The transport direction of the second printing apparatus 30 is the direction of the arrow A2 in FIG. 1 (transport direction A2).

  The collection device 40 includes a defective product collection device 41 and a non-defective product collection device 42. The collection device 40 is provided on the downstream side in the transport direction A2 with respect to the position where the drying device 36 of the second printing device 30 is provided, and the defective product collection device 41 removes defective tablets T. The non-defective tablet T is collected by the non-defective product collecting device 42.

  The defective product collection apparatus 41 includes an injection nozzle 41a and a housing portion 41b. The ejection nozzle 41a is provided in the suction chamber 31f of the second printing apparatus 30, and ejects gas (for example, air) toward the tablets T (defective tablets T) conveyed by the conveyance belt 31a. Then, the tablet T is dropped from the transport belt 31a. At this time, the gas injected from the injection nozzle 41a passes through the suction hole (similar to the suction hole 21g shown in FIG. 2) of the transport belt 31a and hits the tablet T. The injection nozzle 41 a is electrically connected to the control device 50, and its driving is controlled by the control device 50. The accommodating part 41b receives and accommodates the tablet T dropped from the transport belt 31a.

  The non-defective product recovery device 42 includes a gas blowing part 42a and a storage part 42b. The non-defective product collecting device 42 is provided so as to be positioned on the downstream side in the transport direction A2 from the position where the defective product collecting device 41 is provided. The gas blowing portion 42a is provided in the transport device 31 of the second printing apparatus 30 and at the end of the transport device 31, that is, the end of the transport belt 31a on the side of each driven pulley 31c. For example, during the printing process, the gas blowing part 42a always blows gas (for example, air) toward the transport belt 31a, and drops the tablets T from the transport belt 31a. At this time, the gas blown out from the gas blowing portion 42a passes through the suction hole (similar to the suction hole 21g shown in FIG. 2) of the transport belt 31a and hits the tablet T. As this gas blowing part 42a, it is possible to use, for example, an air blow having a slit-like opening extending in a direction (for example, a direction orthogonal) intersecting the transport direction A2 in a horizontal plane. The gas blowing part 42 a is electrically connected to the control device 50, and its driving is controlled by the control device 50. The accommodating part 42b receives and accommodates the tablet T dropped from the transport belt 31a.

  Here, the tablet T that has passed through the defective product recovery apparatus 41 is transported along with the movement of the transport belt 31a, and reaches a position in the transport belt 31a near the end of each driven pulley 31c. Although the suction action does not act on the tablet T at this position, by providing the gas blowing part 42a, the tablet T can be reliably dropped from the transport belt 31a and collected in the storage part 42b.

  The control device 50 includes an image processing unit 51, a print processing unit 52, an inspection processing unit 53, and a storage unit 54. The image processing unit 51 processes an image. The print processing unit 52 performs processing related to printing. The inspection processing unit 53 performs processing related to inspection. The storage 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, and the second printing device 30, and the individual detection devices 22 of the first printing device 20 and the second printing device 30. , 32, the position information of the tablets T, the images transmitted from the individual imaging devices 23, 25, 33, and 35 of the first printing device 20 and the second printing device 30 are received.

(Control board)
As shown in FIGS. 1 and 2, each print head 24 a of the above-described print head device 24 is provided with a common control plate 27. The control plate 27 will be described with reference to FIGS. Note that the control plate 37 (see FIG. 1) for the print head device 34 of the second printing device 30 has basically the same structure, and therefore the description thereof is omitted.

  As shown in FIGS. 3 and 4, the control plate 27 is formed in a rectangular plate shape, for example. The control plate 27 has a longitudinal direction perpendicular to the transport direction A1 of the tablet T in the horizontal plane, and is perpendicular to the lower surface (nozzle surface M1) of each print head 24a. Is provided on the upstream surface in the transport direction A1 (upstream in the transport direction) and is positioned between the transport belt 21a and the height position of the nozzle surface M1 of the print head 24a. The end portion of the control plate 27 on the conveying belt 21a side is formed in a comb-teeth shape in which a plurality of comb teeth 27a are arranged in a direction orthogonal to the conveying direction A1 in the horizontal plane. Each comb tooth 27a is formed in a quadrangular prism shape, for example. Such a control plate 27 is located on the upstream side in the transport direction A1 from each print head 24a, and controls the airflow generated between the transport belt 21a and each print head 24a.

  The length in the longitudinal direction of the control plate 27 (the length in the direction perpendicular to the transport direction A1 in the horizontal plane) is equal to or greater than the length of the row in which all the nozzles 24b of each print head 24a are arranged, the thickness of the control plate 27, That is, the short direction length (the length in the direction along the transport direction A1) is, for example, about 2 mm. Further, the vertical separation distance between the lower end of each comb tooth 27a and the upper surface of the transport belt 21a is, for example, about 1 mm, and the lower end of each comb tooth 27a is higher than the upper surface of the transport belt 21a and is on the upper surface of the transport belt 21a. It exists in the position lower than the vertex of the tablet T mounted. The length of the comb teeth 27a in the short direction (the length in the direction orthogonal to the transport direction A1 in the horizontal plane) is, for example, about 2 mm, and the horizontal separation distance between two adjacent comb teeth 27a is, for example, about 2 mm. However, of the two adjacent comb teeth 27a, the horizontal separation distance between the two comb teeth 27a that sandwich the tablet T conveyed by the conveyance belt 21a is the diameter of the tablet T to be printed (the horizontal direction of the tablet T). According to an example of the maximum size, the diameter is larger. That is, the control plate 27 is formed in a shape that avoids hitting the tablet T conveyed by the conveyance belt 21a. The diameter of the tablet T varies depending on the type of the tablet T, and is, for example, about 5 to 12 mm.

  As the material of the control plate 27, a metal such as SUS (stainless steel) can be used. As a material for the control plate 27, any material conforming to the Food Sanitation Law may be used, and materials other than SUS, for example, aluminum or resin may be used.

  Here, only one control plate 27 is provided as a common member for the print heads 24a arranged in two rows, but the present invention is not limited to this, and may be provided one by one. Further, all the comb teeth 27a are formed in a quadrangular prism shape, but the present invention is not limited to this, and may be formed in, for example, a triangular prism shape, a hexagonal prism shape, a cylindrical shape, or an elliptical prism shape. Moreover, it is not necessary to form all the comb teeth 27a in the same shape, and a part of each comb tooth 27a may have a different shape, or each comb tooth 27a may have a different shape.

  As shown in FIG. 4, each suction hole 21g of the conveyor belt 21a is connected to the suction chamber 21f via a groove 28a and a plurality of through holes 28b formed in the suction chamber 21f. The groove 28a is formed for each transport path of the tablets T so that the transport belt 21a is positioned directly below each suction hole 21g of the transport belt 21a when the transport belt 21a is stretched over the pulley body 21b and each driven pulley 21c. . The through holes 28b are formed in the bottom surface of the groove 28a so as to be aligned in the transport direction A1. When the inside of the suction chamber 21f is sucked, the tablet T on the suction hole 21g is sucked through the groove 28a and each through hole 28b.

  Further, as shown in FIG. 4, the length in the longitudinal direction of the control plate 27 (the length in the direction orthogonal to the transport direction A1 in the horizontal plane) is the same length (the transport direction A1 in the transport direction A1) as the tablet T to be printed. The length in the direction perpendicular to the horizontal plane). For this reason, when the tablet T is sucked and transported through the suction hole 21g, the transport path when the tablet T passes below the control plate 27 is covered by the control plate 27. For example, when the tablet T has a disk shape, the “length in the same direction” is the diameter of the tablet T.

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

  First, various information such as print data required for printing is stored in the storage unit 54 of the control device 50. When a large number of tablets T to be printed are loaded into the hopper 11 of the supply device 10, the tablets T start to be sequentially supplied from the hopper 11 to the alignment feeder 12, and are arranged in two rows by the alignment feeder 12 and moved. The tablets T moving in the two rows are sequentially supplied to the transport belt 21a by the delivery feeder 13. The transport belt 21a is rotated in the transport direction A1 by the rotation of the pulley body 21b and each driven pulley 21c by the motor 21d. For this reason, the tablets T supplied onto the transport belt 21a are transported at a predetermined moving speed in two rows on the transport belt 21a. The transport belt 31a is also rotated in the transport direction A2 by the rotation of the pulley body 31b and each driven pulley 31c by the motor 31d.

  Thereafter, the tablet T on the transport belt 21 a is detected by the detection device 22. Thereby, the position information (position in the transport direction A1) of the tablet T is acquired and input to the control device 50. The position information of the tablet T is stored in the storage unit 54 and used in post-processing. Next, the tablet T on the transport belt 21 a is imaged by the first imaging device 23 at a timing based on the position information of the tablet T described above, and the captured image is transmitted to the control device 50. Based on the individual images transmitted from the first imaging device 23, the position information of the tablet T (for example, the position shift of the tablet T in the X direction, the Y direction, and the θ direction) is generated by the image processing unit 51, It is stored in the storage unit 54. Based on the positional deviation information of the tablet T, printing conditions for the tablet T (ink ejection position, ejection speed, etc.) are set by the print processing unit 52 and stored in the storage unit 54.

  Next, the individual tablets T on the conveyor belt 21a are printed based on the above-described printing conditions at the timing based on the position information of the tablets T, that is, at the timing when the tablets T reach the lower side of the print head device 24. In step 24, printing is executed. In each print head 24a of the print head device 24, ink is appropriately discharged from each nozzle 24b, and identification information such as characters (for example, alphabets, katakana, numbers) and marks (for example, symbols, figures) is printed on the upper surface of the tablet T. Is done.

  The tablet T on which the identification information is printed is captured by the second imaging device 25 at a timing based on the position information of the tablet T described above, and the captured image is transmitted to the control device 50. Based on the individual images transmitted from the second imaging device 25, print position information indicating the print position of the print pattern for each tablet T is generated by the image processing unit 51 and stored in the storage unit 54. Based on the printing position information, the quality of printing on the tablet T is determined by the inspection processing unit 53, and printing quality result information indicating the result of printing quality for each tablet T is stored in the storage unit 54. For example, it is determined whether or not the print pattern is printed at a predetermined position on the tablet T.

  The tablet T after the inspection is transported along with the movement of the transport belt 21 a and passes above the drying device 26. At this time, the ink applied to the tablet T is dried by the drying device 26 while the tablet T passes over the drying device 26, and the tablet T having the dried ink is conveyed along with the movement of the conveying belt 21a. It is located near the end of each conveyor pulley 21c side of the conveyor belt 21a. At this position, the suction action does not act on the tablet T, and the tablet T is released from the state of being held by the transport belt 21 a and is transferred from the first printing device 30 to the second printing device 30.

  Thereafter, the printing process and the inspection process are performed in the second printing apparatus 30 as described above. The tablet T after the inspection is conveyed along with the movement of the conveying belt 31a and passes above the drying device 36. Then, the tablet T from which the ink has been dried reaches the defective product collecting apparatus 41. The defective tablet T is dropped from the conveyor belt 31a by the gas ejected from the ejection nozzle 41a, and is collected by the accommodating portion 41b. On the other hand, the non-defective tablet T passes through the defective product collecting apparatus 41 and reaches the non-defective product collecting apparatus 42. At this position, the non-defective tablet T no longer acts on the tablet T, and is dropped away from the transport belt 31a by the gas blown from the gas blowing part 42a and is collected by the storage part 42b.

  In such a printing process, the tablet T supplied onto the suction hole 21g is held on the transport belt 21a by suction from the suction hole 21g, but the suction hole 21g is not completely blocked by the tablet T. In this case, since air is sucked from the suction hole 21g, an air flow is generated above the suction hole 21g. Further, when the tablet T is transported, an airflow that flows on the transport belt 21a along the transport direction A1 is also generated by the movement of the transport belt 21a. Further, when the print head 24a and its peripheral members are present above the conveying belt 21a, the airflow flowing on the conveying belt 21a hits these members and further turbulence is generated.

  Although airflow is generated in this way, the airflow generated below and around each print head 24 a is controlled by the control plate 27. That is, the control plate 27 includes a shielding portion that blocks airflow generated between the transport belt 21a and the print head 24a along the transport direction A1 by the movement of the transport belt 21a and an opening through which the airflow passes. Control airflow. In the present embodiment, the shielding portion is each comb tooth 27a, and the opening is a space between each comb tooth 27a. For example, the airflow flowing on the transport belt 21 a along the transport direction A <b> 1 hits the control plate 27 and passes between the comb teeth 27 a of the control plate 27. As a result, the airflow generated between the transport belt 21a and each print head 24a is controlled, and the powder adhering to the tablet T and the transport belt 21a is prevented from flying due to the air current generated below and around each print head 24a. Therefore, it is possible to suppress the powder from adhering to the lower surface (nozzle surface) of the print head 24a. Further, on the upstream side of the control plate 27, even if the powder adhering to the tablet T or the transport belt 21a flies by the air current, a part of the powder is blocked by the control plate 27, and therefore adheres to the lower surface of the print head 24a. This can be suppressed.

  Here, as shown in FIG. 5, a conventional tablet printing apparatus that does not have the control plate 27, a tablet printing apparatus that includes a shielding plate that does not have the comb teeth 27 a of the control plate 27, and the tablet printing apparatus of the present embodiment. Printing is performed on the tablet T for 30 minutes using the one control plate 27 that is resinous and the control plate 27 of the tablet printing apparatus 1 of the present embodiment that is metallic. The amount of powder adhering to the head 24a was visually observed, and the occurrence rate of tablets T with poor printing was observed. FIG. 5 shows the result.

  First, in the conventional tablet printing apparatus that does not have the control plate 27, a large amount of powder adheres to the print head 24a, and tablets T with poor printing frequently occur.

  Next, also in the tablet printing apparatus provided with the shielding plate which does not have the comb teeth 27a of the control plate 27, a large amount of powder adheres to the print head 24a as well as the tablet T with poor printing as in the conventional tablet printing apparatus. It occurred frequently. This is because most of the airflow generated above the suction hole 21g hits the shielding plate not having the comb teeth 27a to generate further turbulent flow, and the gap between the shielding plate and the conveyor belt 21a. This is considered to be due to the fact that the increase in the flow velocity causes a further air flow to occur below the print head 24a, causing the powder to fly up.

  Next, in the tablet printing apparatus 1 according to the present embodiment, in which the resinous control plate 27 is provided, adhesion of powder to the print head 24a was hardly seen, and there were no tablets T with poor printing. In addition, adhesion of powder was observed on the control plate 27.

  Next, in the tablet printing apparatus 1 according to the present embodiment, in which the metallic control plate 27 is provided, adhesion of powder to the print head 24a was hardly seen, and there was no tablet T with poor printing. In addition, no powder was observed on the control plate 27.

  Here, when the tablet T sucked and transported on the surface of the transport belt 21a is shaken by the airflow generated between the transport belt 21a and each print head 24a, the posture of the print surface of the tablet T is maintained. There is a risk of disappearing. Furthermore, since the tablet T has a three-dimensional shape and has a thickness, when the tablet T passes below the print head 24a, the distance between the nozzle surface M1 of the print head 24a and the print surface of the tablet T is the same as the nozzle surface M1. It becomes shorter than the distance with the upper surface of the conveyance belt 21a in which the tablet T is not attracted | sucked. For example, the distance between the nozzle surface M1 of the print head 24a and the printing surface of the tablet T is 20 to 25% (20% or more) with respect to the distance between the nozzle surface M1 and the upper surface of the conveyance belt 21a where the tablet T is not sucked. Within a range of 25% or less.

  Therefore, the posture of the printing surface of the tablet T is such that the turbulent airflow generated by the rapid pressure fluctuation when the tablet T passes below the print head 24a or the airflow flowing on the transport belt 21a hits the print head 24a. Susceptible to turbulence generated near If the posture of the printing surface of the tablet T cannot be maintained under the influence of such an air flow, the printing position may be shifted or the printing may be shaken, resulting in a printing failure. Therefore, it is necessary to control the airflow also on the surface of the conveyance belt 21a around the print head 24a.

  As described above, the airflow flowing on the transport belt 21a along the transport direction A1 hits the control plate 27 and passes through the opening in the control plate 27. Thereby, the airflow which flows on the conveyance belt 21a can be rectified into the laminar flow along the conveyance direction A1.

  Further, the length of the control plate 27 in the longitudinal direction (the length in the direction orthogonal to the transport direction A1 in the horizontal plane) is the same as the length of the tablet T to be printed (the direction orthogonal to the transport direction A1 in the horizontal plane). Length) or more. For this reason, the control board 27 can be arrange | positioned so that the conveyance path of the tablet T on the conveyance belt 21a may be covered, and the airflow which flows on the conveyance belt 21a can be rectified into the laminar flow along conveyance direction A1.

  The control plate 27 has a shape that avoids hitting the tablets T conveyed by the conveyance belt 21a, and a part of the lower end of the control plate 27 is higher than the upper surface of the conveyance belt 21a, and the tablets on the conveyance belt 21a. It exists at a position lower than the vertex of T. Therefore, the airflow close to the surface of the transport belt 21a can be rectified into a laminar flow without disturbing the transport of the tablet T.

  As described above, according to the first embodiment, the control plate 27 that controls the airflow generated between the transport belt 21a and the print head 24a is positioned upstream of the print head 24a in the transport direction A1, It is provided above the conveyor belt 21a. As a result, the airflow generated below and around each print head 24a is controlled, so that the powder adhering to the tablet T and the transport belt 21a is prevented from flying due to the airflow generated below and around each print head 24a. be able to. Moreover, even if the powder adhering to the tablet T or the conveyance belt 21a flies by the air current, since a part of the powder is blocked by the control plate 27, it is possible to prevent the powder from adhering to the lower surface of the print head 24a. Therefore, it is possible to suppress the powder of the tablet T from adhering to the lower surface of the print head 24a, and it is possible to suppress the ink ejection failure and the flight direction failure of the print head 24a. Can be suppressed.

  Further, the airflow on the transport belt 21a below and around the print head 24a can be rectified into a laminar flow, thereby suppressing the generation of turbulence. Thereby, since it becomes possible to suppress the shaking of the tablet T sucked and held on the transport belt 21a, it is possible to suppress a decrease in printing quality due to the fact that the posture of the printing surface of the tablet T cannot be maintained.

  The control plate 27 is provided on the print head 24a itself, but is not limited thereto, and may be provided on other members (see the second and third embodiments below). . However, when the control plate 27 is provided in the print head 24a itself, when the type of the tablet T to be printed is changed and the thickness of the tablet T is changed, the height position of the print head 24a is adjusted. The height position of the control plate 27 is automatically adjusted simultaneously with the adjustment of the height position. When the control plate 27 is provided other than the print head 24a, it is necessary to individually adjust the height position of the print head 24a and the height position of the control plate 27, but the control plate 27 is provided on the print head 24a itself. Thus, the height position of the print head 24a and the height position of the control plate 27 can be adjusted at the same time in accordance with the thickness of the tablet T, and efficient adjustment can be realized.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIG. In the second embodiment, the cover 60 that is different from the first embodiment will be described, and the other description will be omitted.

  As shown in FIG. 6, in the second embodiment, a cover 60 is provided. The cover 60 includes a detection device 22 (two detection units 22a), a first imaging device 23 (two imaging units 23a), a print head device 24 (two print heads 24a), and a second imaging device 25 (two It is a housing that houses the imaging unit 25a). The cover 60 has a predetermined distance (for example, from the upper surface of the conveyance belt 21a) in accordance with the thickness (for example, 2 to 4 mm) of the tablet T so that the lower surface thereof does not contact the tablet T conveyed by the conveyance belt 21a. 5-12 mm) and provided above the conveyor belt 21a.

  In the lower surface of the cover 60, two through holes 60a are orthogonal to the transport direction A1 in the horizontal plane so that each detection unit 22a in the cover 60 can detect the tablet T on the transport belt 21a. The two through-holes 60b are arranged in a direction in which the above-described through-holes 60a are arranged so that each imaging unit 23a in the cover 60 can respectively image the tablets T on the transport belt 21a. Are arranged in the same direction. Further, the two through holes 60c are arranged on the lower surface of the cover 60 so that each print head 24a in the cover 60 can print on the tablet T on the transport belt 21a. The two through-holes 60d are formed so as to be arranged in the same direction as the direction, and each imaging unit 25a in the cover 60 can respectively image the tablets T on the transport belt 21a. They are arranged in the same direction as the direction in which 60a is arranged.

  Each through hole 60 a, 60 b, 60 d is closed by a light transmitting member 61, 62 such as glass provided on the bottom surface inside the cover 60. Each through hole 60c is closed by inserting the print head 24a into the through hole 60c via a sealing member 63 such as silicon. In this way, the cover 60 is formed in a sealed state, and the inside of the cover 60 is maintained at a positive pressure (positive pressure).

  On the lower surface of such a cover 60, the control plate 27 is provided between the imaging unit 23a and the print head 24a (at least upstream of the print head 24a in the transport direction A1 of the tablet T). As with the first embodiment, the control plate 27 can control the airflow generated between the transport belt 21a and each print head 24a, so that the print quality is reduced due to the powder of the tablet T. Can be suppressed.

  In addition, according to the present embodiment, when the operation of the tablet printing apparatus 1 is stopped and the entire apparatus is cleaned, the control plate 27 attached to the cover 60 can be removed together by removing the cover 60. The cover 60 and the control plate 27 can be cleaned at a time. Therefore, the cleaning work can be performed efficiently. In addition, since the detection apparatus 22, the 1st imaging device 23, and the 2nd imaging device 25 are covered with the cover 60, powder does not adhere and it is not necessary to clean. Therefore, the cleaning work can be simplified.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIGS. In the third embodiment, differences from the second embodiment (a gas blowing unit and a gas suction unit) will be described, and other descriptions will be omitted.

  As shown in FIGS. 7 and 8, in the third embodiment, in addition to the cover 60, two gas blowing parts 70 and two gas suction parts 80 are provided. Each gas spraying part 70 and each gas suction part 80 function as a deposit removal mechanism. This deposit removal mechanism sprays a gas (for example, air or inert gas) onto the tablet T on the conveyor belt 21a or the deposit (for example, powder or dust) attached to the lower surface of the cover 60, and the tablet T or The deposit is blown off from the lower surface of the cover 60, and the deposit is removed from the tablet T or the lower surface of the cover 60 by sucking the blown deposit with air. Further, when the tablet T is transported by the transport belt 21a, the powder of the tablet T may flutter in the apparatus, and the powder fluttering in the apparatus, particularly the powder fluttering in the vicinity of the cover 60 is also blown into the gas blowing unit 70 and gas suction. It is removed by the part 80.

  The cover 60 is a housing that accommodates the two gas blowing units 70 in addition to the detection device 22, the first imaging device 23, the print head device 24, and the second imaging device 25. As in the second embodiment, the cover 60 is separated from the upper surface of the transport belt 21a by a predetermined distance so that the lower surface of the cover 60 does not come into contact with the tablet T transported by the transport belt 21a. And provided above the conveyor belt 21a. Similar to the second embodiment, the control plate 27 is provided on the lower surface of the cover 60 so as to be positioned between the imaging unit 23a and the print head 24a. Since the control plate 27 can control the airflow generated between the transport belt 21a and each print head 24a, it is possible to suppress a decrease in print quality due to the powder of the tablet T.

  A plurality of through holes 60e are formed on the lower surface of the cover 60 so that each gas spraying portion 70 in the cover 60 can spray gas onto the upper surface of the transport belt 21a. These through holes 60e are formed, for example, in a line in the transport direction A1 for each gas blowing unit 70. The gas blown from the gas blowing unit 70 passes through each through hole 60e that penetrates the lower surface of the cover 60, and is blown onto the transport belt 21a. For example, the diameter of the through hole 60e is several mm (about 2 mm as an example). Each through hole 60e is covered with each gas blowing part 70 provided on the bottom surface inside the cover 60. Thereby, the cover 60 is formed in a sealed state, and the inside of the cover 60 is maintained at a positive pressure (positive pressure).

  Each gas blowing unit 70 is connected to each through hole 60e on the lower surface of the cover 60, and blows gas from the through hole 60e and blows the gas onto the transport belt 21a. Thereby, when the tablet T on the transport belt 21a passes below the gas spraying unit 70, the gas is sprayed toward the tablet T on the transport belt 21a, and the adhered matter adhered to the upper surface of the transport belt 21a or the tablet T. Is blown away from the tablet T. In addition, each gas spraying part 70 is connected to the gas supply part via the flow regulating valve (all are not shown), and gas is supplied to each gas spraying part 70 from the gas supply part.

  In addition, on the lower surface of the cover 60, the guide plate 90 is positioned on the downstream side in the transport direction A <b> 1 below the gas blowing unit 70, and is provided for each gas blowing unit 70. These guide plates 90 are formed in a rectangular shape, and the longitudinal direction thereof is parallel to a direction orthogonal to the transport direction A1 in the horizontal plane, and is tilted down and inclined toward the print head device 24 side. The guide plate 90 causes a part of the gas blown from the gas blowing part 70 through each through hole 60e to flow toward the downstream side in the transport direction A1, and the airflow flowing in the transport direction A1 along the lower surface of the cover 60. Cause it to occur. As a result, the gas is blown onto the deposit attached to the lower surface of the cover 60, and the deposit is blown off from the lower surface of the cover 60. Note that one guide plate 90 is provided for each of the gas blowing units 70 arranged in two rows, but the present invention is not limited to this, and only one guide plate 90 may be provided as a shared member.

  Each gas suction unit 80 is positioned adjacent to the side surface of the transport belt 21a so as to sandwich the transport belt 21a, and is attached to the suction chamber 21f. These gas suction portions 80 each have an intake port 81, an exhaust port 82, and an internal flow path 83 (see FIG. 8).

  The intake port 81 and the exhaust port 82 are formed in a rectangular shape (slit shape) extending in the transport direction A1. The air intake port 81 is an opening for sucking air from the space between the upper surface of the transport belt 21a and the lower surface of the cover 60, and is positioned on the transport belt 21a side in the gas suction unit 80, and is higher than the upper surface of the transport belt 21a. In the position. The opening of the intake port 81 is provided so that the end is located upstream of the control plate 27 in the transport direction A1. As a result, the gas from the gas blowing unit 70 does not flow to the respective print heads 24a, and the nozzles 24b of the respective print heads 24a are prevented from being dried to cause a discharge failure or discharged from the nozzles 24b. This prevents the ink from being distorted due to the influence of the airflow. The exhaust port 82 is positioned on the side of the conveyance belt 21a in the gas suction unit 80, is provided at a position lower than the conveyance belt 21a, and is connected to the inside of the suction chamber 21f. The internal flow path 83 is formed inside the gas suction unit 80 and is a flow path that connects the intake port 81 and the exhaust port 82.

  Here, when the inside of the suction chamber 21 f is sucked for transporting the tablet T, air is sucked from the exhaust port 82 in each gas suction portion 80. Then, air in the space between the upper surface of the conveyance belt 21 a and the lower surface of the cover 60 is sucked from the intake port 81 through the internal flow path 83 connected to the exhaust port 82. Thereby, the deposits blown off by the gas blown by the gas blowing unit 70 are sucked together with the air from the intake port 81.

  Note that the suction force of the gas suction unit 80 can be adjusted by changing the length of the suction port 81 in the height direction. However, the length of the intake port 81 in the height direction is preferably shorter than the height of the tablet T. Usually, the suction force for sucking air from the suction port 81 is not set to a suction force such that the tablet T is sucked from the suction port 81, but the case where the suction force is not sufficiently adjusted or the type of the tablet T ( There is a concern that the tablet T is sucked from the air inlet 81, for example, when the size of the tablet T is different. For this reason, by making the length in the height direction of the intake port 81 shorter than the height of the tablet T, it is possible to suppress the tablet T from being sucked from the intake port 81. Note that the length in the longitudinal direction of the air inlet 81 is appropriately set based on the suction range required to remove the deposits attached to the tablets T on the transport belt 21a.

  In addition, the position of the tablet T (the position of the tablet T in the X direction, the Y direction, and the θ direction, the posture of the tablet T, etc.) by the suction force by which the gas from the gas blowing unit 70 or the air from the air inlet 81 is sucked. The amount of gas from the gas blowing unit 70 and the suction force of air from the air intake port 81 so that the tablet T does not change on the conveyor belt 21a or the tablet T falls from the conveyor belt 21a. Is set.

  Further, the blowing of gas from the gas blowing unit 70 and the suction of air from the gas suction unit 80 are always performed during the operation of the tablet printing apparatus 1. Even if the tablet T does not arrive at the gas spraying unit 70, the detection device 22, the first imaging device 23, and the print head device 24 for a certain time, the gas spraying from the gas spraying unit 70 and the gas suction unit 80 By sucking air, it is possible to remove the powder adhering to the conveyor belt 21a and to prevent the powder from adhering to the conveyor belt 21a. If a large amount of powder of the tablet T adheres to the transport belt 21a or the transparent member 61, the portion where the powder is accumulated is imaged by the first imaging device 23, and the tablet T does not exist. Regardless, erroneous detection may occur and printing may be performed on the conveyance belt 21a. However, such erroneous detection is always performed by blowing gas from the gas blowing unit 70 and sucking air from the gas suction unit 80. Can be prevented.

  Further, when the tablet T is newly supplied with the powder adhering to the transport belt 21a, the tablet T slips on the transport belt 21a and falls from the transport belt 21a or takes an attitude on the transport belt 21a. It will change. By always blowing and sucking the gas by the deposit removing mechanism during the operation of the tablet printing apparatus 1, slipping of the tablet T on the transport belt 21a when the transport of the tablet T is resumed can be suppressed.

  In the configuration as described above, when the tablet T is printed, gas is blown out from the through holes 60e onto the transport belt 21a by the gas blowing portions 70. Further, the air in the suction chamber 21f is sucked, and accordingly, the air in the space between the upper surface of the conveyor belt 21a and the lower surface of the cover 60 is sucked from the individual intake ports 81 of the respective gas suction portions 80. ing. In this state, the tablet T being transported by the transport belt 21 a is sprayed with gas by the gas spraying unit 70 when passing under the gas spraying unit 70. At this time, when an adherent is attached to the tablet T, the attached matter is blown off from the tablet T, and the blown-off attached matter is sucked together with air by the gas suction unit 80. In this way, since the adhered matter adhering to the tablet T is removed, it is possible to suppress printing on the tablet T in a state where the adhered matter is adhered, and it is possible to suppress a decrease in print quality. .

  In addition, the gas is blown onto the transport belt 21a by the gas spraying unit 70, and a part of the gas is guided by the guide plate 90 so as to flow along the lower surface of the cover 60 in the transport direction A1. As a result, the gas is blown against the deposit attached to the lower surface of the cover 60, and the deposit is blown off from the lower surface of the cover 60. The deposits blown off are sucked by the gas suction unit 80 together with air. In this way, since the deposits attached to the lower surface of the cover 60, that is, the translucent members 61 and 62 are removed, it is possible to suppress abnormal detection and abnormal recognition, and it is possible to suppress deterioration in print quality. Furthermore, since the powder of the tablet T flying near the cover 60 can also be sucked and removed, it is possible to suppress the powder of the tablet T from adhering to the tablet T, the lower surface of the cover 60, the transport belt 21a, and the like. . In addition, the longitudinal direction length of the guide plate 90, the length along the conveyance direction A1, and the inclination angle are set to a length and an angle at which deposits attached to the translucent members 61 and 62 can be blown off. And it is provided so that the tablet T conveyed below may not be touched. In addition, the guide plate 90 is not limited to a flat plate, and may be a plate having a curved shape as long as the attached matter attached to the translucent members 61 and 62 can be blown away.

  Further, as described above, a part of the gas flows along the lower surface of the cover 60 by the guide plate 90, but the gas flowing in the transport direction A1 along the lower surface of the cover 60 collides with the control plate 27, A part of the gas is sucked from the suction port 81 of the gas suction unit 80. At this time, the deposits blown off from the lower surface of the cover 60 are also sucked from the intake port 81 together with the gas. Thereby, since the airflow flowing along the lower surface of the cover 60 and the deposits blown off from the lower surface of the cover 60 are suppressed from adversely affecting the printing of each print head 24a, it is possible to suppress a decrease in print quality.

  In addition, the above-mentioned conveyance belt 21a may vibrate when the tablet T is conveyed. At this time, even if the conveying belt 21a is shaken and the adhering matter (for example, powder or dust) adhering to the conveying belt 21a tries to fly up, the rising is suppressed by the gas blown from the gas blowing unit 70, and the adhering matter is further reduced. Even if it soars, the soaring deposit is sucked by the gas suction unit 80. Thereby, since the deposit | attachment adhering to the conveyance belt 21a is suppressed from adhering to the tablet T on the conveyance belt 21a, the fall of print quality can be suppressed.

  Further, in order to suppress the above-described powder behavior due to the airflow, the suction force of the suction hole 21g, that is, the suction force for sucking the tablet T is applied to all or a part of the transport belt 21a (for example, a predetermined region including the lower part of the print head 24a). ) Can also be weakened. However, if the suction force for sucking the tablet T is weakened, the conveyor belt 21a may vibrate in the reduced suction force portion. At this time, even if the conveying belt 21a sways and the adhering matter adhering to the conveying belt 21a tries to fly up, the rising is suppressed by the gas blown from the gas blowing unit 70, and even if the adhering matter rises up, it flew up. The deposit is sucked by the gas suction unit 80. Thereby, since the deposit | attachment adhering to the conveyance belt 21a is suppressed from adhering to the tablet T on the conveyance belt 21a, the fall of print quality can be suppressed.

(Cover modification)
In the above description, the through holes 60e of the cover 60 are exemplified to be arranged in a line along the transport direction A1, but the present invention is not limited to this, and the lines are arranged in two or more lines. Alternatively, they may be formed randomly rather than in rows. Further, the through hole 60e may be formed in a slit shape.

  In the above description, the detection device 22, the first imaging device 23, the print head device 24, and the second imaging device 25 are illustrated as being housed in the cover 60. However, the present invention is not limited to this. Since the cover 60 is provided, powder does not adhere to the detection device 22, the first imaging device 23, the print head device 24, and the imaging device 25 itself, and only the cover 60 can be removed and cleaned. It is efficient when switching the varieties of tablets T. However, the cover 60 may not be provided as long as the deposit removing mechanism functions sufficiently. At this time, the guide plate 90 is attached to the gas blowing unit 70 itself. Thus, by eliminating the cover 60, the height positions of the detection device 22, the first imaging device 23, the print head device 24, and the second imaging device 25 can be freely changed.

(Modification 1 and Modification 2 of the gas suction unit)
In the above description, the intake port 81 of the gas suction unit 80 is illustrated as being formed in a rectangular shape extending in the transport direction A1, but the present invention is not limited to this, and for example, gradually becomes narrower along the transport direction A1. It may be formed in a triangular shape (Modification 1), or a plurality of rectangular intake ports 81 having different extension lengths may be arranged in the height direction with their left ends aligned (Modification Example) 2). In these cases, the suction force in the gas suction unit 80 gradually decreases along the transport direction A1, that is, toward the print head device 24 side (the right side in FIG. 7). Since the generated air flow is suppressed from adversely affecting the printing of the print head device 24, it is possible to more reliably suppress a decrease in print quality. In addition, in the vicinity of the suction port 81 on the downstream side in the transport direction A1 of the gas suction unit 80, the gas from the gas blowing unit 70 is not supplied directly, but only supplied through the guide plate 90. There is no problem even if the amount of air sucked from the intake port 81 is reduced. Note that it is also possible to use circular or elliptical intake ports 81 in a single row or in a plurality of rows along the transport direction A1 with different sizes.

(Modification 3 of the gas suction unit)
In the above description, it has been exemplified that the suction force of the gas suction unit 80 can be adjusted by changing the length of the suction port 81 of the gas suction unit 80 in the height direction. For example, a suction force adjusting member (not shown) may be provided in the internal channel 83 of the gas suction unit 80. This suction force adjusting member has a rectangular (slit-shaped) through-hole extending in the transport direction A1, is provided in the interior so as to close the internal flow path 83, and passes through the internal flow path 83 Adjust the suction force by changing the flow rate. Several types of suction force adjusting members having different slit widths (widths in the direction perpendicular to the conveyance direction A1 in the through hole in the horizontal plane) are prepared, and from these suction force adjusting members, depending on the required suction force By selecting and using one suction force adjusting member, the suction force of the gas suction unit 80 can be easily adjusted.

  In addition, although the through-hole of the suction force adjusting member is formed in a rectangular shape extending in the transport direction A1, it is not limited thereto, and may be formed in various shapes such as a circular shape, an elliptical shape, and a triangular shape. Further, the number of through holes is not limited and may be plural. For example, a plurality of through holes such as a circular shape and an elliptical shape may be formed so as to be aligned in a row in the transport direction A1, or may be formed so as to be aligned in a plurality of rows (for example, two rows or three rows), Moreover, you may form irregularly (randomly).

  Further, the suction force adjusting member that forms the through hole is detachable, and may be exchanged when changing the type of the tablet T to be printed. By doing so, it is possible to easily adjust the suction force even if the printing object is changed. The suction force adjusting member may be attached anywhere within the gas suction unit 80, may be attached to the intake port 81, or may be attached to the exhaust port 82.

  Further, although the example in which the gas suction unit 80 is provided only on the upstream side of the print head 24a in the transport direction A1 has been described, the present invention is not limited to this and may be provided in other places. You may provide in the perimeter of the conveyance belt 21a, or one part. Providing a plurality of gas suction sections 80 increases the chances of sucking the powder adhering to the transport belt 21a, so that the print quality due to the powder adhering to the print head 24a or the position of the tablet T being shifted during transport. Can be suppressed.

  In particular, when the gas suction unit 80 is provided in a portion where the centrifugal force acts (pulley body 21b, driven pulley 21c portion), the powder adhering to the conveyor belt 21a is likely to float due to the centrifugal force. Part 80 can suck the powder. Further, since the suction hole 21g of the conveyor belt 21a in the driven pulley 21c portion is not connected to the suction chamber 21f, powder is not sucked by the suction hole 21g. Therefore, it is particularly effective to provide the gas suction part 80 in this part.

<Fourth Embodiment>
Next, a fourth embodiment will be described with reference to FIG. Note that in the fourth embodiment, differences from the first embodiment (configuration of the control plate) will be described, and other descriptions will be omitted.

  As shown in FIG. 9, the end of the control belt 27A according to the fourth embodiment on the side of the conveying belt 21a is a saw in which a plurality of comb teeth 27b are arranged in the longitudinal direction (a direction orthogonal to the conveying direction A1 in the horizontal plane). It is formed into a shape. Each comb tooth 27b is formed so as to become gradually narrower downward (that is, the upper surface of the conveyor belt 21a). Such a control plate 27A makes it possible to control the airflow generated between the conveyor belt 21a and the print head 24a, as in the above-described embodiments, so that the print quality is reduced due to the powder of the tablet T. Can be suppressed.

  In addition to the above-described comb teeth 27b being gradually thinned, only the tips of the comb teeth 27b may be thinned, or the comb teeth 27b may be gradually narrowed downward. Alternatively, the thickness may be gradually increased downward. Alternatively, the center portion of the comb teeth 27b may be thickened.

<Fifth Embodiment>
Next, a fifth embodiment will be described with reference to FIGS. In the fifth embodiment, differences from the first embodiment (configuration of the control plate) will be described, and other descriptions will be omitted.

  As shown in FIG. 10, the control plate 27B according to the fifth embodiment includes a support portion 27c and a plurality of comb teeth 27d. The support part 27c is formed in a rectangular plate shape. Each comb tooth 27d is provided at the lower end of the support portion 27c so as to be aligned in the longitudinal direction of the support portion 27c (the direction orthogonal to the transport direction A1 in the horizontal plane). Such a control plate 27B makes it possible to control the airflow generated between the transport belt 21a and each print head 24a as in the above-described embodiments. The decrease can be suppressed.

  Further, the airflow flowing on the transport belt 21a along the transport direction A1 hits the control plate 27B, and passes through openings (spaces between the comb teeth 27d) in the control plate 27B through which the airflow passes. With such a control plate 27B, the airflow flowing on the transport belt 21a can be rectified into a laminar flow along the transport direction A1 as in the above-described embodiments. Such a control plate 27B can rectify the airflow on the conveyance belt 21a below and around the print head 24a into a laminar flow, thereby suppressing the generation of turbulence. As a result, it is possible to suppress the shaking of the tablet T sucked and held by the transport belt 21a, so that the posture of the printing surface of the tablet T cannot be maintained when the tablet T passes below the print head 24a. It is possible to suppress a decrease in print quality due to the above.

  In addition to the above-described support portion 27c having a rectangular plate shape, the support portion 27c may be formed in another plate shape or a rod shape, and the comb teeth 27d are gradually narrowed downward. Alternatively, it may be made gradually thicker downward, or only the tips of the comb teeth 27d may be made thinner. Alternatively, the center portion of the comb teeth 27d may be thickened. Further, as shown in FIG. 11, comb teeth 27d may also be provided above the tablet T so as not to contact the tablet T (at a height not contacting the tablet T). In the case of FIG. 11, two comb teeth 27a that sandwich the tablet T conveyed by the conveyor belt 21a are defined as “two adjacent comb teeth 27a”, and the horizontal separation distance is the diameter of the tablet T to be printed. According to (an example of the maximum size in the horizontal direction of the tablet T), it is larger than its diameter.

<Sixth Embodiment>
Next, a sixth embodiment will be described with reference to FIG. In the sixth embodiment, differences from the first embodiment (configuration of the control plate) will be described, and other descriptions will be omitted.

  As shown in FIG. 12, the control plate 27C according to the sixth embodiment is formed so that a plurality of rectangular through holes 27e are arranged in a line in the longitudinal direction (a direction orthogonal to the transport direction A1 in the horizontal plane). Has been. Such a control plate 27C makes it possible to control the airflow generated between the conveyor belt 21a and each print head 24a, as in the above-described embodiments, so that the print quality caused by the powder of the tablet T can be controlled. The decrease can be suppressed.

  Further, the airflow flowing on the transport belt 21a along the transport direction A1 hits the control plate 27C, and passes through an opening (through hole 27e) in the control plate 27C through which the airflow passes. Such a control plate 27C can rectify the airflow flowing on the transport belt 21a into a laminar flow along the transport direction A1 as in the above-described embodiments. As a result, it is possible to suppress the shaking of the tablet T sucked and held by the transport belt 21a, so that the posture of the printing surface of the tablet T cannot be maintained when the tablet T passes below the print head 24a. It is possible to suppress a decrease in print quality due to the above.

  The shape of the through hole 27e is not limited to the rectangular shape, and may be an elliptical shape or a triangular shape, for example. Further, the interval between the through holes 27e is not limited to a fixed one, and may be irregular. For example, the through hole 27e may not be provided above the tablet T. Alternatively, the opening area of the upper through-hole 27e through which the tablet T passes may be made smaller or larger than the opening area of the through-hole 27e provided elsewhere.

<Seventh Embodiment>
Next, a seventh embodiment will be described with reference to FIG. Note that in the seventh embodiment, differences from the first embodiment (configuration of the control plate) will be described, and other descriptions will be omitted.

  As shown in FIG. 13, in the control plate 27D according to the seventh embodiment, a plurality of circular through holes 27f are arranged in the longitudinal direction of the rectangle (the direction orthogonal to the transport direction A1 in the horizontal plane) and the short direction. It is formed so as to be arranged in a line at a predetermined interval. For example, a punching board or a mesh plate can be used as the control plate 27D. Such a control plate 27D makes it possible to control the airflow generated between the transport belt 21a and the print head 24a as in the above-described embodiments, so that the printing quality is reduced due to the powder of the tablet T. Can be suppressed.

  Further, the airflow flowing on the transport belt 21a along the transport direction A1 hits the control plate 27D, and passes through an opening (through hole 27f) in the control plate 27D through which the airflow passes. With such a control plate 27D, the airflow flowing on the transport belt 21a can be rectified into a laminar flow along the transport direction A1 as in the above-described embodiments. As a result, it is possible to suppress the shaking of the tablet T sucked and held by the transport belt 21a, so that the posture of the printing surface of the tablet T cannot be maintained when the tablet T passes below the print head 24a. It is possible to suppress a decrease in print quality due to the above.

  Note that the shape of the through hole 27f is not limited to a circular shape, and may be, for example, a square shape, an elliptical shape, or a triangular shape. Further, the interval between the through holes 27f is not limited to a fixed value, and may be irregular.

  Here, it is also possible to combine each embodiment shown in FIG.4, FIG.9, FIG.10, FIG.11, FIG.12 and FIG. Moreover, in each embodiment, according to the size and shape of the tablet T, the size and shape of the comb teeth 27a, 27b, or 27d, or the size and shape of the through holes 27e or 27f are appropriately selected. Since the air flow generated varies depending on the type of the tablet T, the size of the comb teeth 27a, 27b or 27d or the size or shape of the through holes 27e or 27f is changed accordingly. In order to control the direction of air flow and the distribution of flow velocity, the size and shape of the comb teeth 27a, 27b or 27d, or the size and shape of the through holes 27e or 27f are selected as appropriate.

  It should be noted that the “shielding portions that block airflow” in the control plates 27, 27A, 27B are a plurality of comb teeth 27a, 27b, 27d. The “opening through which the airflow passes” is a space between the comb teeth of the plurality of comb teeth 27a, 27b, and 27d. In addition, the “shielding portion that blocks airflow” in the control plates 27C and 27D is a portion other than the plurality of through holes 27e and 27f. The “openings through which the airflow passes” are a plurality of through holes 27e and 27f.

  Further, since the control plate 27, 27A or 27B according to any one of the first to fifth embodiments is formed in a comb-tooth shape, the inside of the apparatus is cleaned in order to change the type of the tablet T to be printed. In this case, the control plate 27, 27A or 27B can be easily cleaned and kept clean as compared with 27C or 27D according to the sixth or seventh embodiment.

  Further, since the control plate 27, 27A or 27B is formed in a comb-teeth shape, each of the control plates 27, 27A or 27B is allowed to pass between the comb teeth of the plurality of comb teeth 27a, 27b, 27d by passing the airflow flowing on the conveyor belt 21a. The airflow along the comb teeth can be rectified, and the airflow can be more easily rectified into a laminar flow along the conveyance direction A1. Thereby, as described above, it is possible to perform printing while suppressing the generation of turbulence that may shake the tablet T sucked and held on the surface of the transport belt 21a.

  Further, the control plate 27, 27A or 27B is formed in a comb-like shape, and is arranged so as to open toward the upper surface of the transport belt 21a. That is, the lower end of the control plate 27, 27A or 27B is open, but when the lower end of the control plate 27, 27A or 27B is not open, the lower end of the control plate 27, 27A or 27B is conveyed. It is conceivable that turbulent airflow is further generated when the gap with the belt 21a is narrowed and the flow velocity of the airflow passing through the gap is increased. However, the control plate 27, 27A, or 27B can be formed in a comb-teeth shape to reduce the portion that blocks the airflow in the vicinity of the conveyor belt 21a. For this reason, printing is performed while suppressing the shaking of the tablet T held by suction without causing further turbulence on the surface of the conveyor belt 21a below the print head 24a due to an increase in the flow velocity in the vicinity of the conveyor belt 21a. Can do.

<Other embodiments>
In each of the above-described embodiments, it is exemplified that the tablets T are conveyed in two rows. However, the present invention is not limited to this, and the number of rows may be one row, three rows, four rows or more, and is particularly limited. It is not something.

  Further, in each of the above-described embodiments, only one conveying belt 21a is illustrated. However, the present invention is not limited to this, and two or more conveying belts 21a may be provided, and the number is not particularly limited. Absent. For example, a plurality of conveyor belts 21a can be arranged in parallel.

  In each of the above-described embodiments, the circular suction hole is used as the suction hole 21g of the transport belt 21a. However, the present invention is not limited to this, and a rectangular, elliptical, or slit-like suction hole is used. The shape of the suction hole 21g of the conveyor belt 21a is not particularly limited.

  Further, in each of the above-described embodiments, the print head 24a is provided for each conveyance path of the tablets T. However, the present invention is not limited to this. For example, two or more rows of tablets T can be formed by one print head 24a. Printing may be performed.

  Further, in each of the above-described embodiments, the print head in which the nozzles 24b are arranged in a row is illustrated as the inkjet print head 24a. However, the present invention is not limited to this, and for example, a print head in which the nozzles 24b are arranged in a plurality of rows is used. It may be used. Further, a plurality of print heads 24a may be used side by side along the conveyance direction A1 of the tablet T.

  Further, in each of the above-described embodiments, the first printing device 20 and the second printing device 30 are arranged so as to overlap each other, and both sides or one side of the tablet T is printed. However, the present invention is not limited thereto. For example, only the first printing device may be provided and only one side of the tablet T may be printed.

  Moreover, in each above-mentioned embodiment, although it illustrated that the gas blowing part 42a was provided in the good quality recovery apparatus 42, it is not restricted to this, For example, the 2nd conveying apparatus 31 in the conveying apparatus 21 is provided. You may make it prepare in the location which delivers the tablet T to the conveying apparatus 21 from the side edge part or the delivery feeder 13. FIG. That is, the gas blowing part 42a may be used at a location where the tablet T is desired to be detached from the transport belt 21a.

  Moreover, in each above-mentioned embodiment, although the gas blowing part 42a illustrated blowing out gas always during a process, it is not restricted to this, You may make it blow off intermittently.

  In the above-described embodiments, the control plates 27 and 37 are illustrated as flat plates. However, the present invention is not limited to this, and may be curved plates, for example.

  Further, in each of the above-described embodiments, the control plate 27 is exemplified as being arranged to be perpendicular to the lower surface (nozzle surface M1) of each print head 24a. However, the present invention is not limited to this. For example, it may be provided so as to be inclined with respect to the transport direction A1.

  In the second embodiment, the control plate 27 is provided on the lower surface of the cover 60 so as to be positioned between the imaging unit 23a and the print head 24a. However, the present invention is not limited to this. The control plate 27 may be provided at the tip of the cover 60 on the upstream side in the transport direction A1 (upstream side in the tablet transport direction).

  In the third embodiment, the guide plate 90 has a rectangular shape. However, the guide plate 90 may have a shape in which comb teeth and through holes are provided, that is, a shape having an opening and a shielding portion. In this case, the gas ejected from the gas blowing unit 70 can be rectified, and the reattachment of the deposit can be suppressed by the rectified airflow. Moreover, generation | occurrence | production of the new turbulence by ejecting gas from the gas spraying part 70 can also be suppressed. If the guide plate 90 in FIG. 7 has a shape having an opening and a shielding portion, the control plate 27 can be omitted.

  Here, as the above-mentioned tablet, a tablet used for medicine, food and drink, washing, industrial use or fragrance can be included. In addition, tablets include uncoated tablets, sugar-coated tablets, film-coated tablets, enteric-coated tablets, gelatin-encapsulated tablets, multilayer tablets, dry-coated tablets, and various capsule tablets such as hard capsules and soft capsules. Can be included. Furthermore, the shape of the tablet includes various shapes such as a disk shape, a lens shape, a triangle, and an ellipse. In addition, when the tablet to be printed is for medical use or food and drink, edible ink is suitable as the ink to be used. As the edible ink, any of synthetic dye ink, natural dye ink, dye ink, and pigment ink may be used.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Tablet printer 21a Conveyor belt 21g Suction hole 21f Suction chamber 24a Print head 24b Nozzle 27 Control board 27A Control board 27B Control board 27C Control board 27D Control board 27a Comb tooth 27b Comb tooth 27c Support part 27d Comb tooth 27e Through hole 27f Hole 31a Conveying belt 37 Control plate 37a Comb tooth 60 Cover 70 Gas spraying part 80 Gas suction part M1 Nozzle surface T Tablet

Claims (8)

A conveying belt having a suction hole connected to the suction chamber, and sucking and transporting the tablet to the suction hole;
An ink jet type print head having a nozzle surface on which nozzles are formed, the nozzle surface being directed to the transport belt and provided above the transport belt, and performing printing on the tablets transported by the transport belt; ,
An airflow that is positioned upstream of the print head in the transport direction of the tablet and is provided between the transport belt and the height position of the nozzle surface of the print head, and is generated between the transport belt and the print head A control board for controlling,
A tablet printing apparatus comprising:   The control plate is arranged such that its longitudinal direction is perpendicular to the tablet transport direction in a horizontal plane, and the air flows between the transport belt and the print head by flowing along the tablet transport direction. The tablet printing apparatus according to claim 1, further comprising: a shielding portion that blocks the airflow and an opening through which the airflow passes.   A plurality of comb teeth are formed at the end of the control plate on the side of the transport belt so as to be aligned along a direction intersecting the transport direction of the tablets within a horizontal plane. The tablet printing apparatus as described.   The tablet printing apparatus according to claim 1, wherein a plurality of through holes are formed in the control plate so as to pass through the control plate along a transport direction of the tablet.   The part of the lower end of the control plate is located at a position higher than the upper surface of the conveyor belt and lower than the top of the tablet on the conveyor belt. The tablet printing apparatus according to claim 1.   Among the plurality of comb teeth, a horizontal separation distance between two adjacent comb teeth that sandwich the tablet transported by the transport belt is larger than a maximum horizontal size of the tablet. The tablet printing apparatus according to claim 3.   The tablet printing apparatus according to claim 3, wherein the control plate is provided with comb teeth so as to be positioned above the tablet transported by the transport belt so as not to contact the tablet. . A housing for accommodating the print head;
A gas blowing section and a gas suction section provided on the upstream side in the transport direction of the tablet from the printing head;
Further comprising
The gas spray unit sprays gas on the upper surface of the conveyor belt,
The tablet printing apparatus according to any one of claims 1 to 7, wherein the gas suction unit sucks the gas blown by the gas blowing unit.

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