WO2019171791A1

WO2019171791A1 - Printing device and printing method

Info

Publication number: WO2019171791A1
Application number: PCT/JP2019/001702
Authority: WO
Inventors: 信行中野
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2018-03-05
Filing date: 2019-01-21
Publication date: 2019-09-12
Also published as: CN111801084A; JP6921769B2; JP2019150359A; CN111801084B; KR102505696B1; KR20200111786A

Abstract

A printing device (1) includes a delivery mechanism (10), an imaging mechanism (20), and a head (30). The delivery mechanism (10) shuttles a particulate tablet (9) between a first position (P1) and a second position (P2). The imaging mechanism (20) images the tablet (9) at an imaging position (Pa) between the first position (P1) and the second position (P2). The head (30) ejects ink drops on the surface of the tablet (9) at a printing position (Pb) between the imaging position (Pa) and the second position (P2). By shuttling the tablet (9), imaging of the tablet (9) prior to printing and imaging of the tablet (9) after printing can be performed by one imaging mechanism (20). Thus, the size of the printing device (1) can easily be reduced.

Description

Printing apparatus and printing method

The present invention relates to a printing apparatus and a printing method for printing an image on the surface of a granular material by an inkjet method.

文字 Characters and codes for identifying products are printed on the surface of tablets that are pharmaceuticals. Marks and illustrations may also be printed on tablet confectionery such as ramune. 2. Description of the Related Art Conventionally, a technique for printing an image by an inkjet method on the surface of such granular materials such as tablets and tablet confections is known. For example, Patent Document 1 describes a tablet printing apparatus that performs printing processing on randomly supplied tablets using an inkjet printer.

The apparatus of Patent Document 1 includes a detection line sensor camera (detection imaging unit) that images a tablet before printing, and an inspection line sensor camera (inspection imaging unit) that images a tablet after printing. . The device of Patent Document 1 prints on each tablet based on the position, posture, front and back of the tablet detected by the detection line sensor camera. The inspection line sensor camera is used to inspect the printing state on each tablet.

JP 2013-112432 A

However, the configuration described in Patent Document 1 requires at least two imaging units, that is, a detection line sensor camera and an inspection line sensor camera. For this reason, it is difficult to reduce the size of the printing apparatus. In addition, the manufacturing cost of the printing apparatus is increased by the plurality of imaging units.

This invention is made in view of such a situation, and it aims at providing the technique which can reduce the number of imaging | photography mechanisms in the printing apparatus which prints an image by the inkjet system on the surface of a granular material.

In order to solve the above-described problem, the first invention of the present application is a printing apparatus that prints an image on the surface of a granular material by an inkjet method, and transports the granular material from a first position to a second position; Photographing the particulate matter at a transportation mechanism that transports the particulate matter from the second position to the first position and a photographing position between the first position and the second position. A mechanism, a head that ejects ink droplets onto the surface of the granular material at a printing position between the photographing position and the second position, the transport mechanism, the photographing mechanism, and a control unit that controls the head. The control unit includes: a) a step of photographing the granular material during the forward conveyance by the photographing mechanism; and b) after the step a), during the forward conveyance or during the backward conveyance. On the surface of the granular material, A step of discharging the ink droplets from de, after c) said step b), using the particulate matter in the return transport, executes the steps of imaging by the imaging mechanism.

A second invention of the present application is the printing apparatus according to the first invention, wherein the control unit ejects ink droplets from the head onto the surface of the granular material being transported in the forward path in the step b).

A third invention of the present application is the printing apparatus of the first invention or the second invention, wherein the transport mechanism includes a holding plate having suction holes for sucking the particulate matter, the first position, and the second position. A plate moving mechanism for moving the holding plate.

4th invention of this application is a printing apparatus of any one invention from 1st invention to 3rd invention, Comprising: The said control part is based on the image acquired in the said process a), before printing of the said granular material. An inspection is performed, and the post-print inspection of the granular material is performed based on the image acquired in step c).

A fifth invention of the present application is the printing apparatus according to any one of the first to fourth inventions, wherein at least a part of a conveyance path between the first position and the second position, and the photographing. A cover that covers the mechanism and the head is further provided, and the cover has an opening for carrying in and out the granular material at the first position.

6th invention of this application is a printing apparatus of any one invention from 1st invention to 5th invention, Comprising: The reverse mechanism which reverses the front and back of the said granular material is further provided, The said control part is the said process a) After performing steps c) to c), the front and back of the granular material are reversed by the reversing mechanism, and the steps a) to c) are further performed.

The seventh invention of the present application is the printing apparatus according to any one of the first to sixth inventions, wherein the granular material is a tablet.

According to an eighth aspect of the present invention, there is provided a printing method for printing an image on the surface of a granular material by an inkjet method, wherein a) the granular material being transported forward from the first position to the second position is photographed by a photographing mechanism. Step b) After step a), ejecting ink droplets from the head onto the surface of the granular material during the forward transfer or during the return pass from the second position to the first position; c ) After the step b), the step of photographing the granular material being transported in the return path by the photographing mechanism.

A ninth invention of the present application is the printing method according to the eighth invention, wherein, in the step b), ink droplets are ejected from the head onto the surface of the granular material being transported forward.

10th invention of this application is the printing method of 8th invention or 9th invention, Comprising: The said granular material is a tablet.

According to the first to tenth inventions of the present application, the granular material can be reciprocally conveyed, so that the photographing of the granular material before printing and the photographing of the granular material after printing can be performed by one photographing mechanism. . This facilitates downsizing of the printing apparatus.

In particular, according to the second and ninth inventions of the present application, the position of the particulate matter is unlikely to occur between the photographing of the particulate matter in step a) and the ejection of the ink droplets in step b). Therefore, an image can be printed with high accuracy on the surface of the granular material based on the result of photographing the granular material in step a).

It is a top view of a printing apparatus. It is a side view of a printing apparatus. FIG. 3 is a block diagram illustrating a connection between a control unit and each unit in the printing apparatus. 6 is a flowchart illustrating a flow of processing in the printing apparatus. It is the flowchart which showed the flow of the process which concerns on a modification.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the direction in which a plurality of granular materials are conveyed is the “conveying direction”, the direction perpendicular to the conveying direction is the “width direction”, and the direction is perpendicular to the conveying direction and the width direction. Is referred to as a “height direction”.

<1. About the configuration of the printing device>
FIG. 1 is a top view of a printing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a side view of the printing apparatus 1. The printing apparatus 1 is an apparatus that prints an image on the surface of each tablet 9 by an inkjet method while conveying a plurality of tablets 9 that are granular materials. The tablet 9 may be an uncoated tablet (bare tablet) or a coated tablet such as a sugar-coated tablet or a film-coated tablet (FC tablet). The tablet 9 may be a capsule including a hard capsule and a soft capsule. Further, the “particulate matter” in the present invention is not limited to a tablet as a pharmaceutical product, and may be a tablet as a health food or a tablet confectionery such as ramune.

As shown in FIGS. 1 and 2, the printing apparatus 1 according to the present embodiment includes a transport mechanism 10, a photographing mechanism 20, a head 30, a cover 40, and a control unit 50.

The transport mechanism 10 is a mechanism that transports a plurality of tablets 9 while holding them. The transport mechanism 10 of this embodiment includes a holding plate 11, a suction mechanism 12, and a plate moving mechanism 13. The holding plate 11 is a flat holding unit that holds a plurality of tablets 9. The holding plate 11 is arranged so that the upper surface thereof is in a horizontal posture. A plurality of suction holes 110 are provided on the upper surface of the holding plate 11. For example, the plurality of suction holes 110 are arranged at equal intervals in the transport direction and the width direction. The plurality of tablets 9 are arranged one by one in these suction holes 110.

The suction mechanism 12 is a mechanism for generating a negative pressure in the plurality of suction holes 110. As shown in FIG. 2, the suction mechanism 12 includes an intake pipe 121 and an airflow generation device 122. One end of the intake pipe 121 is connected to the plurality of suction holes 110. The other end of the intake pipe 121 is connected to the airflow generator 122. For example, a fan is used for the airflow generation device 122. When the airflow generation device 122 is driven, an airflow is generated in the intake pipe 121 from the plurality of suction holes 110 toward the airflow generation device 122. Thereby, a negative pressure lower than the atmospheric pressure is generated in the plurality of suction holes 110. The tablet 9 is sucked and held in the suction hole 110 by this negative pressure.

The plate moving mechanism 13 is a mechanism for moving the holding plate 11. For the plate moving mechanism 13, for example, a linear motor is used. However, instead of the linear motor, a mechanism that converts the rotational motion of the motor into a straight motion via a ball screw may be used.

When the plate moving mechanism 13 is operated, the holding plate 11 is moved between a first position P1 indicated by a solid line in FIGS. 1 and 2 and a second position P2 indicated by a two-dot chain line in FIGS. , Reciprocate horizontally. The first position P1 is a position where the tablet 9 is carried into and out of the holding plate 11. The second position P2 is a return position of the reciprocating movement. By the movement of the holding plate 11, the plurality of tablets 9 are transported from the first position P1 to the second position P2 (forward path transport), and the plurality of tablets 9 are transported from the second position P2 to the first position P1 (return path transport). ) Is realized.

As described above, the holding plate 11 does not simply place the tablets 9, but holds the tablets 9 by negative pressure. Thereby, at the time of conveyance of the tablet 9, it can suppress that the position and attitude | position of the tablet 9 change, or the tablet 9 falls off. In particular, when switching from the forward conveyance to the backward conveyance, a large inertia force in the conveyance direction acts on the tablet 9. However, in this embodiment, since the tablet 9 is held by suction, the position and posture of the tablet 9 can be maintained.

The photographing mechanism 20 is a mechanism for photographing the upper surface of the tablet 9 at a photographing position Pa between the first position P1 and the second position P2. As shown in FIGS. 1 and 2, the photographing mechanism 20 of this embodiment includes a mirror 21 and a camera 22. The mirror 21 is disposed above the photographing position Pa in a posture inclined with respect to the height direction and the width direction. For the camera 22, for example, a digital camera having an image sensor such as a CCD or a CMOS is used. The camera 22 takes an image of the tablet 9 reflected by the mirror 21. Thereby, multi-gradation digital data including an image of the tablet 9 is obtained. If the mirror 21 is used as in the present embodiment, the camera 22 can be disposed on the side of the mirror 21 instead of above the shooting position Pa. Thereby, the height of the printing apparatus 1 can be suppressed.

The head 30 is a mechanism that ejects ink droplets onto the upper surface of the tablet 9 at a printing position Pb between the photographing position Pa and the second position P2. A plurality of nozzles are provided on the lower surface of the head 30. The head 30 ejects ink droplets from each nozzle based on the print data input from the control unit 50. Thereby, an image is printed on the upper surface of the tablet 9. The printing apparatus 1 according to the present embodiment prints a monochrome image on the upper surface of the tablet 9 by using one head 30. However, the printing apparatus 1 may include a plurality of heads 30 and record a multicolor image on the upper surface of the tablet 9 by ejecting different color inks from the heads 30. For the ink ejected from the head 30, edible ink manufactured from raw materials approved by the Japanese Pharmacopoeia, the Food Sanitation Act, or the like is used.

Note that the printing apparatus 1 may include a cap that covers the lower surface of the head 30 when printing is suspended, and a mechanism that cleans the lower surface of the head 30.

The cover 40 constitutes a part of the casing of the printing apparatus 1. The photographing mechanism 20, the head 30, and at least a part of the transport path between the first position P1 and the second position P2 are covered with the cover 40. The cover 40 has an opening 41 in the vicinity of the first position P1. When the tablet 9 is carried in, the holding plate 11 is arranged at the first position P1, and the tablet 9 is set on the upper surface of the holding plate 11 exposed to the outside through the opening 41. Further, when the tablet 9 is carried out, the holding plate 11 is arranged at the first position P1, and the tablet 9 is taken out from the upper surface of the holding plate 11 exposed to the outside through the opening 41.

The control unit 50 is means for controlling the operation of each unit of the printing apparatus 1. FIG. 3 is a block diagram showing connections between the control unit 50 and each unit in the printing apparatus 1. As conceptually shown in FIG. 1, the control unit 50 includes a computer having a processor 51 such as a CPU, a memory 52 such as a RAM, and a storage unit 53 such as a hard disk drive. The storage unit 53 stores a computer program CP and data D for executing print processing and inspection processing described later.

Further, as shown in FIG. 3, the control unit 50 is connected to the above-described suction mechanism 12, the plate moving mechanism 13, the camera 22, and the head 30 so as to be communicable in a wired or wireless manner. The control unit 50 temporarily reads the computer program CP and data D stored in the storage unit 53 into the memory 52, and the processor 51 performs arithmetic processing based on the computer program CP, thereby operating the above-described units. Control. Thereby, the printing process and the inspection process for the plurality of tablets 9 proceed.

Further, the printing apparatus 1 includes a display unit 60 in addition to the above configuration. The display unit 60 is connected to the control unit 50 so as to be communicable by wire or wirelessly. For example, a liquid crystal display is used for the display unit 60. The display unit 60 displays various information related to a printing process and an inspection process, which will be described later, on the screen based on a signal input from the control unit 50.

<2. About print processing and inspection processing>
The printing apparatus 1 sequentially performs pre-printing inspection, printing, and post-printing inspection on the tablet 9 while reciprocally transporting the plurality of tablets 9 between the first position P1 and the second position P2. . Hereinafter, the flow of these processes will be described with reference to the flowchart of FIG.

In the initial state, the holding plate 11 is disposed at the first position P1. A user of the printing apparatus 1 first places the tablet 9 in the plurality of suction holes 110 of the holding plate 11. The tablets 9 are sucked and held in the suction holes 110 by the negative pressure generated by the suction mechanism 12 (step S1).

When the plurality of tablets 9 are held on the holding plate 11, the control unit 50 starts the operation of the plate moving mechanism 13. Thereby, the outward conveyance toward the 2nd position P2 from the 1st position P1 of the some tablet 9 hold | maintained at the holding plate 11 and the holding plate 11 is started (step S2).

When the plurality of tablets 9 reach the photographing position Pa, the control unit 50 operates the camera 22 of the photographing mechanism 20. Thereby, the upper surfaces of the plurality of tablets 9 being transported forward are photographed by the camera 22 (step S3). The acquired image data is transmitted from the camera 22 to the control unit 50. Moreover, the control part 50 test | inspects the state of each tablet 9 before printing based on the image data received from the camera 22 (inspection before printing) (step S4). Specifically, the presence or absence of the tablet 9 in each suction hole 110, the front and back posture of each tablet 9, the rotational posture of each tablet 9 about the vertical axis, the positional deviation of each tablet 9 with respect to the suction hole 110, the shape defect of each tablet 9 Presence or absence, etc. are determined. The inspection result in step S4 is displayed on the display unit 60.

Subsequently, when the plurality of tablets 9 reach the printing position Pb, the control unit 50 operates the head 30. Thereby, ink droplets are ejected from the plurality of nozzles of the head 30 toward the tablet 9. As a result, an image is printed on the upper surface of each tablet 9 during forward conveyance (step S5). At this time, the control part 50 adjusts the image which should be printed on each tablet 9 based on the test | inspection result of step S3 mentioned above. For example, the control unit 50 selects an appropriate image in accordance with the front and back posture of each tablet 9 from the front image and the back image, and selects the selected image in accordance with the rotation posture of each tablet 9. Rotate. Then, the control unit 50 inputs a print signal to the head 30 based on the adjusted image. As a result, an appropriate image is printed on the upper surface of each tablet 9 in an appropriate posture.

Eventually, when the tablet 9 reaches the second position P2, the control unit 50 stops the operation of the plate moving mechanism 13. Thus, the forward conveyance of the holding plate 11 and the plurality of tablets 9 held by the holding plate 11 is completed (step S6). Thereafter, the control unit 50 operates the plate moving mechanism 13 in the opposite direction to steps S2 to S6. Thereby, the return path conveyance from the 2nd position P2 to the 1st position P1 of the several tablet 9 hold | maintained at the holding plate 11 and the holding plate 11 is started (step S7).

In the backward conveyance, the plurality of tablets 9 pass through the printing position Pb without discharging ink droplets from the head 30. When the plurality of tablets 9 reach the photographing position Pa, the control unit 50 operates the camera 22 of the photographing mechanism 20. Thereby, the upper surfaces of the plurality of tablets 9 being transported in the backward direction are photographed by the camera 22 (step S8). The acquired image data is transmitted from the camera 22 to the control unit 50.

Further, the control unit 50 inspects the printing state of each tablet 9 (inspection after printing) based on the image data received from the camera 22 (step S9). Specifically, for example, the control unit 50 compares the image data received from the camera 22 with the normal image data prepared in advance, so that the image printed on the upper surface of each tablet 9 is normal. It is determined whether or not there is. The inspection result in step S9 is displayed on the display unit 60.

Eventually, when the tablet 9 reaches the first position P1, the control unit 50 stops the operation of the plate moving mechanism 13. Thereby, the return path conveyance of the plurality of tablets 9 held on the holding plate 11 and the holding plate 11 is completed (step S10). Thereafter, the control unit 50 stops the operation of the suction mechanism 12. Thereby, adsorption | suction of the tablet 9 in each adsorption hole 110 is cancelled | released. The user of the printing apparatus 1 takes out a plurality of printed tablets 9 from the holding plate 11 (step S11).

As described above, in the printing apparatus 1, while the tablet 9 is reciprocatingly conveyed, the photographing of the tablet 9 before printing (step S3), the printing (step S5), and the photographing of the tablet 9 after printing (step S8). Are sequentially executed. The photographing of the tablet 9 before printing (step S3) and the photographing of the tablet 9 after printing (step S8) are executed by the same photographing mechanism 20 at the same photographing position Pa. For this reason, the number of photographing mechanisms can be reduced as compared with the case where photographing of the tablet 9 before printing (step S3) and photographing of the tablet 9 after printing (step S8) are performed by separate photographing mechanisms. . Therefore, if the configuration of the present embodiment is adopted, the printing apparatus 1 can be easily downsized.

In particular, in the present embodiment, the printing on the tablet 9 is executed during the forward conveyance. If it does in this way, printing (step S5) can be performed immediately after imaging | photography (step S3) and pre-printing inspection (step S4) of the tablet 9 before printing. Further, photographing of the tablet 9 before printing (step S3), inspection before printing (step S4), and printing (step S5) can be executed without switching the direction of conveyance of the tablet 9. For this reason, after taking the tablet 9 before printing (step S3) and pre-printing inspection (step S4), the position of the tablet 9 is unlikely to be shifted until printing. Therefore, an image can be printed with high accuracy on the upper surface of each tablet 9 based on the inspection result in step S4.

<3. Modification>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

In the above embodiment, the printing on the tablet 9 was performed during the forward conveyance. However, printing on the tablet 9 may be performed during the return path conveyance. FIG. 5 is a flowchart when printing is performed during the return path conveyance. In the example of FIG. 5, only the photographing of the tablet 9 (step S3) and the pre-printing inspection (step S4) are performed during the forward conveyance. Then, after the transport direction is switched at the second position P2 (steps S6 to S7), ink droplets are ejected from the head 30 onto the upper surface of the tablet 9 being transported in the backward path to perform printing (step S5). Thereafter, the photographing of the tablet 9 during the return path conveyance (step S8) and the post-printing inspection (step S9) are executed.

In the above embodiment, the plurality of tablets 9 are directly placed on the upper surface of the holding plate 11. However, a plurality of tablets 9 may be placed on the upper surface of the holding plate 11 via a separate tray. The tray may have, for example, a shape that can be attached to and detached from the holding plate 11 and has a through hole at a position corresponding to each suction hole 110. Further, a recess may be provided at a position corresponding to the suction hole 110 on the upper surface of the holding plate 11 or the upper surface of the tray. And you may make it the tablet 9 fit in the said recessed part. If it does in this way, position shift of tablet 9 accompanying conveyance can be controlled more.

In the above embodiment, the tablet 9 is transported horizontally between the first position P1 and the second position P2. However, the conveyance direction of the tablet 9 between the first position P1 and the second position P2 may be an oblique direction or a vertical direction. Moreover, in said embodiment, the tablet 9 was conveyed linearly between the 1st position P1 and the 2nd position P2. However, the conveyance path of the tablet 9 between the first position P1 and the second position P2 may be curved or broken.

In the above embodiment, the transport mechanism 10 transports the tablet 9 by the holding plate 11. However, the transport mechanism of the present invention may transport the tablet 9 by other methods. For example, the tablets 9 may be conveyed by rotating the belt while adsorbing and holding the tablets 9 on the surface of the belt of the belt conveyor. Alternatively, the tablet 9 may be conveyed by rotating the drum while adsorbing and holding the tablet 9 on the surface of the cylindrical drum.

Further, in addition to the configuration of the printing apparatus 1 of the above embodiment, a reversing mechanism for reversing the front and back of the tablet 9 on the holding plate 11 may be further provided. The reversing mechanism may be, for example, a mechanism that transfers the tablets 9 while reversing them from one holding plate or tray to another holding plate or tray. When printing on the tablet 9, for example, after executing steps S1 to S10 in FIG. 4, the front and back of the tablet 9 may be reversed, and steps S2 to S11 in FIG. 4 may be further executed. If such a reversing mechanism is added, images can be automatically printed on both the front and back sides of the tablet 9. Therefore, pre-print inspection, printing, and post-print inspection for one surface of the tablet 9 and pre-print inspection, printing, and post-print inspection for the other surface of the tablet 9 can be performed using the same mechanism. it can. Thereby, the printing apparatus 1 can be significantly downsized.

Further, in addition to the configuration of the printing apparatus 1 of the above-described embodiment, a drying mechanism that dries the ink attached to the surface of the tablet 9 may be further provided. For example, the drying mechanism may be configured to blow hot air on the upper surface of the tablet 9 to vaporize the solvent in the ink attached to the upper surface of the tablet 9. What is necessary is just to arrange | position the drying mechanism in the 2nd position P2, for example.

Further, the detailed configuration of the printing apparatus may be changed as appropriate without departing from the spirit of the present invention. Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Printing apparatus 9 Tablet 10 Conveyance mechanism 11 Holding plate 12 Suction mechanism 13 Plate moving mechanism 20 Imaging mechanism 21 Mirror 22 Camera 30 Head 40 Cover 41 Opening 50 Control part 60 Display part 110 Adsorption hole 121 Intake pipe 122 Airflow generator P1 1st Position P2 Second position Pa Shooting position Pb Printing position

Claims

A printing apparatus that prints an image on the surface of a granular material by an inkjet method,
A transport mechanism for performing forward path transport for transporting the granular material from the first position to the second position and return path transport for transporting the granular material from the second position to the first position;
A photographing mechanism for photographing the granular material at a photographing position between the first position and the second position;
A head that ejects ink droplets onto the surface of the granular material at a printing position between the photographing position and the second position;
A controller that controls the transport mechanism, the imaging mechanism, and the head;
With
The controller is
a) photographing the granular material during the forward conveyance by the photographing mechanism;
b) after the step a), ejecting ink droplets from the head onto the surface of the granular material during the forward transfer or the return pass; and
c) After the step b), the step of photographing the granular material being conveyed on the return path by the photographing mechanism;
Run the printing device.
The printing apparatus according to claim 1,
In the step b), the control unit ejects ink droplets from the head onto the surface of the granular material being transported in the forward path.
The printing apparatus according to claim 1 or 2, wherein
The transport mechanism is
A holding plate having an adsorption hole for adsorbing the particulate matter;
A plate moving mechanism for moving the holding plate between the first position and the second position;
A printing apparatus.
A printing apparatus according to any one of claims 1 to 3, wherein
The controller is
Based on the image acquired in the step a), the granular material is inspected before printing,
A printing apparatus that performs a post-printing inspection of the granular material based on the image acquired in step c).
The printing apparatus according to any one of claims 1 to 4, wherein:
A cover that covers at least a part of a conveyance path between the first position and the second position, the imaging mechanism, and the head;
The printing apparatus according to claim 1, wherein the cover has an opening for carrying in and carrying out the granular material at the first position.
The printing apparatus according to any one of claims 1 to 5, wherein:
A reversing mechanism for reversing the front and back of the granular material;
The control unit, after executing the steps a) to c), further reverses the front and back of the granular material by the reversing mechanism, and further executes the steps a) to c).
The printing apparatus according to any one of claims 1 to 6, wherein
The printing apparatus, wherein the granular material is a tablet.
A printing method for printing an image on the surface of a granular material by an inkjet method,
a) a step of photographing the granular material during the forward conveyance from the first position to the second position by a photographing mechanism;
b) after the step a), ejecting ink droplets from the head onto the surface of the granular material during the forward conveyance or during the backward conveyance from the second position to the first position;
c) After the step b), the step of photographing the granular material being conveyed on the return path by the photographing mechanism;
A printing method.
The printing method according to claim 8, comprising:
A printing method in which, in the step b), ink droplets are ejected from the head onto the surface of the granular material being transported forward.
The printing method according to claim 8 or 9, wherein
The printing method, wherein the granular material is a tablet.