Patent Grant
10814644
This application is based upon and claims the benefit of priority from International Application No. PCT/JP2017/033638, filed on Sep. 19, 2017, Japanese Patent Applications No. 2016-195009, filed on Sep. 30, 2016 and No. 2016-196101, filed on Oct. 4, 2016; the entire contents of all of which are incorporated herein by reference.
Embodiments described herein relate generally to a tablet printing apparatus and a tablet printing method.
A technique that uses an inkjet print head to preform printing is known for printing identification information such as characters, letters, marks or the like on a tablet. In the tablet printing apparatus that uses this technique, a plurality of tablets are conveyed in a row by a conveyor. The inkjet print head is located above the conveyor, and ejects ink (for example, edible ink) from its nozzle toward each of the tablets passing under it to print identification information on the tablets on the conveyor.
The print head of the tablet printing apparatus is subject to regular maintenance to maintain its normal operation. Generally, each time the maintenance of the print head is required, the conveyance of tablets has to be stopped. During this period, printing on tablets is suspended. Therefore, the productivity decreases as the frequency of maintenance increases or the time taken for a single maintenance activity increases.
According to one embodiment, a tablet printing apparatus includes: a conveyor configured to convey a tablet having an outer shape that does not determine the printing direction of a print pattern to be printed thereon; an inkjet print head including a plurality of nozzles each configured to eject a liquid to print the print pattern on the tablet being conveyed; and a controller configured to control the print head to perform printing on the tablet being conveyed such that the printing direction of the print pattern is changed at predetermined intervals at least between a first direction which is parallel to or crosses the conveying direction of the tablet, and a second direction which crosses the conveying direction, and in which more nozzles are used for printing than in the first direction.
According to another embodiment, a tablet printing apparatus includes: a conveyor configured to convey a tablet having an outer shape that does not determine the printing direction of a print pattern to be printed thereon; an inkjet print head including a plurality of nozzles each configured to eject a liquid to print the print pattern on the tablet being conveyed; and a controller configured to control the print head to perform printing on the tablet being conveyed such that the print pattern is printed in a direction which crosses the conveying direction of the tablet, and in which more nozzles are used for printing than when the print pattern is printed in a direction parallel to the conveying direction.
According to still another embodiment, a tablet printing method includes: conveying, by a conveyor, a tablet having an outer shape that does not determine the printing direction of a print pattern to be printed thereon; printing, by an inkjet print head, the print pattern on the tablet being conveyed, the print head including a plurality of nozzles each configured to eject a liquid; and controlling, by a controller, the print head to perform printing on the tablet being conveyed such that the printing direction of the print pattern is changed at predetermined intervals at least between a first direction which is parallel to or crosses the conveying direction of the tablet, and a second direction which crosses the conveying direction, and in which more nozzles are used for printing than in the first direction.
According to still another embodiment, a tablet printing method includes: conveying, by a conveyor, a tablet having an outer shape that does not determine the printing direction of a print pattern to be printed thereon; printing, by an inkjet print head, the print pattern on the tablet being conveyed, the print head including a plurality of nozzles each configured to eject a liquid; and controlling, by a controller, the print head to perform printing on the tablet being conveyed such that the print pattern is printed in a direction which crosses the conveying direction of the tablet, and in which more nozzles are used for printing than when the print pattern is printed in a direction parallel to the conveying direction.
A first embodiment will be described with reference to
(Basic Configuration)
As illustrated in
The supply device 10 includes a hopper 11 and a chute 12. The hopper 11 stores a number of tablets T and sequentially supplies the tablets T to the chute 12. The chute 12 aligns the tablets T in a plurality of rows, and supplies them to the conveying device 20. The supply device 10 is electrically connected to the control device 90, and is driven under the control of the control device 90.
For example, the tablets T may be completely circular in plan view and have no split line.
The conveying device 20 includes a conveyor belt (see
In the conveying device 20, the conveyor belt 21 rotates together with the driven pulley 23 as the drive pulley 22 is rotated by the drive unit 24 to convey the tablets T thereon in the direction of arrow A1 in
The detecting device 30 includes a plurality of detection units (detectors) 31 (see
The imaging device 40 includes a plurality of imaging units (imagers) 41 (see
The printing device 50 includes inkjet print heads 51. The two print heads 51 are arranged above the conveyor belt 21. The print heads 51 are located on the downstream side of the imaging device 40 in the conveying direction A1. The print heads 51 each include a plurality of nozzles 51a (see
The two post-printing imaging units 52 are arranged above the conveyor belt 21, and are located on the downstream side of the print heads 51 in the conveying direction A1. The post-printing imaging units 52 are arranged in a direction crossing the conveying direction A1 (for example, a direction perpendicular to the conveying direction A1) in the horizontal plane. Each of the post-printing imaging units 52 performs imaging at the time when each of the tablets T reaches just under it to capture an image including the upper surface of the tablet T, and sends the image to the image processing device 80. Similarly to the imaging units 41, various cameras having an imaging device such as CCD or CMOS can be used as the post-printing imaging units 52. The post-printing imaging units 52 are each electrically connected to the control device 90 via the image processing device 80, and are driven under the control of the control device 90. There may also be provided an illumination for imaging as necessary.
The collecting device 60 is located on the downstream side of the post-printing imaging units 52 in the conveying direction A1. The collecting device 60 is arranged at the end of the conveying device 20, i.e., the end of the conveyor belt 21 on the downstream side in the conveying direction A1. The collecting device 60 is configured to be able to sequentially receive and collect the tablets T released from the hold of the conveying device 20 and dropped therefrom. Incidentally, the conveying device releases the hold of each of the tablets T on the conveyor belt 21 when the tablet T reaches a desired position such as, for example, the end of the conveyor belt 21 on the downstream side in the conveying direction A1.
The image processing device 80 receives each image captured by the imaging device 40, and processes the image using a known image processing technique. Having received an image from the imaging device 40, the image processing device 80 detects the position shift of the tablet T in the X and Y directions. The position shift in the X and Y directions refers herein to a shift in the position of the tablet T with respect to the center of the imaging field of view, and indicates how much the tablet T has shifted from the center. In this embodiment, for example, the X direction corresponds to the conveying direction A1, while the Y direction corresponds to a direction perpendicular thereto.
The image processing device 80 sends information on the detected position shift of the tablet T in the X and Y directions to the control device 90. The image processing device 80 adds identification information of one of the imaging units 41 to the position shift information to be sent to the control device 90. Thereby, the control device 90 can identify that the sent position shift information corresponding to the tablet T of which row, where the tablet T is conveyed in two rows on the conveyor belt 21.
The image processing device 80 also receives each image captured by the post-printing imaging unit 52, and processes the image using a known image processing technique. Having received an image from the post-printing imaging unit 52, the image processing device 80 checks whether print state (printed condition) in the image received from the post-printing imaging unit 52 matches printing condition for the tablet T (described later), and sends information on the check to the control device 90. According to the information received from the image processing device 80, when the match rate is, for example, 90% or more, the control device 90 determines the tablet T to be “acceptable” and collects it by the collecting device 60. When the match rate is less than 90%, the control device 90 determines the tablet T to be “defective” and collects it in a defective product box (not illustrated).
The control device 90 includes an input/output device (circuitry) 91, a microcomputer 92 that intensively controls each unit, a storage 93 that stores various information, various programs, and the like, and a print data switching unit (switcher) 94. The control device 90 controls the supply device 10, the conveying device 20, the imaging device 40, the post-printing imaging unit 52, and the printing device 50 based on various information (for example, process information) and various programs. In addition, the control device 90 receives detection signals and the like sent from the detecting device 30 and the position detector 24a.
The input/output device 91 receives input of various types of information such as a print pattern, and outputs various types of information. The storage 93 stores the input print pattern. The storage 93 also stores print data composed of a dot pattern. The print data is generated as to which of the nozzles 51a of the inkjet print heads 51 is to be used for ejecting ink and the timing thereof from the print pattern. Further, rotated print data is generated by rotating the print data with respect to a direction parallel to the conveying direction A1 of the tablets T, which is set as 0 degrees, and stored in the storage 93. The rotated print data is generated at each predetermined angle. The angle by which the print data is rotated is hereinafter referred to as “print data rotation angle”. The print data switching unit 94 switches pieces of print data, each obtained at a different print data rotation angle, from one to another at predetermined intervals.
For example, the storage 93 stores 0° print data, 15° print data, 30° print data, and 45° print data obtained by rotating a print pattern such as characters, letters, or marks to be printed on the tablets T by increments of 15 degrees from 0 degrees. The control device 90 selects one from these pieces of print data to set printing condition. The nozzles 51a to be used vary depending on the angle of the print data selected (details will be described later). Note that the term “0° print data” as used herein refers to data of a print pattern to be printed in parallel with the conveying direction A1 of the tablets T (a pattern printed based on this data is hereinafter referred to as “reference pattern”). The angles 0°, 15°, 30°, and 45° each indicate the print data rotation angle. The direction defined by the print data rotation angle with respect to the conveying direction A1 of the tablets T is the printing direction with respect to the conveying direction A1 of the tablets T.
In the field of tablet printing, there has been known a technology for printing on a tablet having a split line (hereinafter referred to as “split-line tablet”) or a tablet in a shape that is not completely circular (hereinafter referred to as “irregular-shaped tablet”). When printing is performed on tablets having directional properties such as split-line tablets or irregular-shaped tablets, their shifts in the e direction are detected based on images captured by the imaging device 40, and the print data stored in the storage 93 is rotated to be used. On the other hand, when printing is performed on tablets that are completely circular in plan view and have no split line as with the tablets T of this embodiment, there is no need to rotate the print data since the tablets T has no directional property. That is, the tablet T is a tablet on which printing can be performed without considering the directionality, i.e., a tablet having an outer shape that does not determine the printing direction or orientation of a print pattern to be printed thereon. Incidentally, “completely circular” is a term that covers circular shapes that are perfectly or almost perfectly round. Accordingly, printing is always performed using data having an angle in a reference direction (for example, 0 degrees). If printing is always performed using data of the same angle, only the nozzles 51a in a specific range are kept being used intensively.
As described above, various types of inkjet print heads having a drive element such as a piezoelectric element, a heating element, or a magnetostrictive element can be used as the print heads 51. The drive element has a usage limit, and, when the drive element reaches its usage limit (lifetime), maintenance is required to replace the drive element together with the print head 51. The nozzles 51a in a specific range, which are kept being used intensively as described above, use the drive element more frequently than those in other ranges. As a result, the drive element reaches the end of its lifetime earlier, and the print heads 51 need to be replaced more frequently. A considerable amount of time is required for maintenance to replace the print heads 51. Printing on the tablets T is suspended during this stop period. Therefore, the productivity decreases greatly as the frequency of maintenance increases.
Besides, ink adheres to the periphery of the nozzles 51a used at high frequency, which causes liquid pooling and thus prevents proper ejection of the ink. Meanwhile, in the nozzles 51a used at low frequency, ink is thickened, or solid matter is precipitated, resulting in that the ink may not be properly ejected from the nozzles 51a. In order to prevent this, it is conventionally necessary to perform maintenance work such as cleaning of the periphery of the nozzles 51a, for example, about once every 10 minutes, by using a maintenance device (not illustrated). Generally, as described above, each time the print heads 51 require maintenance, printing on tablets has to be suspended. Since printing is not performed on the tablets T during this suspension period, the productivity decreases as the frequency of maintenance increases or the time taken for a single maintenance activity increases.
The present inventors have found that this can be solved by using ingenuity at the time of setting printing conditions. In the following, the setting of printing conditions will be explained in detail along with the description of a printing step performed by the tablet printing apparatus 1.
(Printing Step)
A printing step (printing process) performed by the tablet printing apparatus 1 will be described.
Various types of information such as print data required for printing is stored in the storage 93 of the control device 90. Besides, a number of tablets T to be printed are fed in the hopper 11 of the supply device 10. When the tablet printing apparatus 1 is driven, the conveyor belt 21 of the conveying device 20 rotates in the conveying direction A1 as the drive pulley 22 and the driven pulley 23 are rotated by the drive unit 24. While the conveyor belt 21 is rotating, the supply device 10 sequentially supplies the tablets T onto the conveyor belt 21 not at regular intervals but at random. The tablets T are conveyed on the conveyor belt 21 at a predetermined speed.
Each of the detection units 31 detects each of the tablets T on the conveyor belt 21, and feeds the control device 90 with a detection signal as a trigger signal. Thereafter, each of the imaging units 41 captures an image of each of the tablets T on the conveyor belt 21. The imaging unit 41 captures an image of the upper surface of the tablet T at the timing based on the trigger signal, i.e., at the time when the tablet T reaches under the imaging unit 41, and sends the image to the image processing device 80. The image processing device 80 generates information on the position shift of the tablet T (for example, the position shift of the tablet T in the X and Y directions) based on the image received from the imaging unit 41, and sends the position shift information to the control device 90.
At this time, the print data rotation angle is set. As described above, the storage 93 of the control device 90 stores 0° print data, 15° print data, 30° print data, and 45° print data obtained by rotating a print pattern such as characters, letters, or marks by increments of 15 degrees from 0 degrees. First, the control device 90 selects the 0° print data having a print data rotation angle of 0 degrees, and sets printing condition based on the 0° print data. The control device 90 of this embodiment adds the position shift information of the tablets T received from the image processing device 80 to the selected print data and corrects the printing conditions for each of the tablets T when, for example, the position of the tablet T has shifted in the Y direction or the like.
Thereafter, the printing device 50 performs printing on each of the tablets T on the conveyor belt 21 by using the 0° print data (first direction) at the timing based on the trigger signal, i.e., at the time when the tablet T reaches under one of the print heads 51 based on the printing condition. The print head 51 of the printing device 50 ejects ink as appropriate from each of the nozzles 51a to print identification information such as characters, letters, or marks on the upper surface of the tablet T. The ink applied to the tablet T is dried before the collecting device 60 collects the tablet T. After the printing, the post-printing imaging unit 52 captures an image of the tablet T. When the control device 90 determines print state on the tablet T to be “acceptable”, the tablet T is released from the hold at the downstream end of the conveyor belt 21 and dropped therefrom to be collected by the collecting device 60.
When a predetermined time (for example, 3 minutes) set in advance has elapsed since the start of the printing process, the control device 90 switches the 0° print data to the 15° print data (second direction) having a print data rotation angle of 15 degrees, and changes the printing condition based on the 15° print data. Then, the above printing process is performed under the new printing condition. While a predetermined time that is set in advance is cited as the interval at which the print data is switched, the print data may be switched based on, for example, the number of times the drive element has been used (ejection count), the number of tablets on which printing has been performed, or the like.
When the predetermined time has elapsed since the change of the printing condition, the control device 90 switches the 15° print data to the 30° print data (third direction) having a print data rotation angle of 30 degrees, and changes the printing condition based on the 30° print data. Then, the above printing process is performed under the new printing condition.
When the predetermined time has elapsed again, the control device 90 switches the 30° print data to the 45° print data (fourth direction) having a print data rotation angle of 45 degrees, and changes the printing condition based on the 45° print data. Then, the above printing process is performed under the new printing condition.
When the predetermined time has elapsed again, the control device 90 switches the 45° print data back to the 0° print data. After that, the printing process is continued while the printing condition are changed in this manner according to the switching of the 15°, 30°, or 45° print data each time the predetermined time has elapsed.
As described above, each time the predetermined time has elapsed, print data are switched from one to another, which are different in print data rotation angle by 15 degrees. When, for example, one hour has elapsed since the start of the printing process, the printing process is suspended, and maintenance work is performed by a maintenance device (not illustrated).
As illustrated in
In this manner, pieces of print data each having a different print data rotation angle are switched from one to another at predetermined time intervals, and accordingly printing conditions are changed. With this, the process of ink ejection can be distributed among the nozzles 51a. Each time printing conditions are changed, the tablets T are printed with patterns of different angles with respect to the conveying direction A1. When checking the print state based on an image captured by the post-printing imaging unit 52, the image processing device 80 checks the match rate based on the image of the tablet captured after printing while taking into account the print data rotation angle used in printing on the tablet, i.e., printing condition.
When the position of the tablet T has shifted in the Y direction, as described above, the control device 90 of this embodiment adds the position shift information of the tablets T received from the image processing device 80 to the selected print data and corrects the printing conditions for each of the tablets T. As the position shift information is taken into account, the nozzles 51a to be used are also shifted in the Y direction by an amount corresponding to the position shift of the tablet T in the Y direction. Since the print data is shifted in the Y direction by an amount corresponding to Y directional variation in the supply position of the tablets T, the number of nozzles 51a to be used increases at least by the amount. This also contributes to, although in a small manner, equalization. Incidentally, the print data may be rotated not only depending on the variation in the supply position, but also on the Y direction shift of the nozzles 51a to be used to make it more appropriate. The Y direction sift may be performed within a range that does not affect the appearance of the print.
For example, there may be provided a head moving mechanism (actuator) 53 configured to move the print heads 51 in the Y direction (an example of a direction crossing the conveying direction A1 in the horizontal plane) as illustrated in
In the case of shifting the print pattern as described above, a reference pattern is shifted in the Y direction. In addition, print data may be generated at each predetermined angle based on the reference pattern shifted in the Y direction. Alternatively, the print pattern may be shifted in the Y direction with respect to each print data. With this, nozzles in an area where their use frequency is constantly low can be shifted to an area where they are constantly used. Thereby, it is possible to further equalize the lifetimes of the print heads 51 as a whole.
Further, after reducing the number of the nozzles 51a to be used (thinning out the nozzles 51a to be used), the reduced nozzles 51a and the selected nozzles 51a may be used alternately, which may be performed in combination with the above methods. If there are a plurality of nozzle arrays, they may be used while being switched from one array to another, which may be performed in combination with the above method of shifting the print pattern. For example, in the case of the print heads 51 each having two arrays of nozzles with a resolution of 300 dpi, the two arrays of nozzles 51a may be used alternately such that either one of the nozzle arrays is used (150 dpi printing). In the case of the print heads 51 each having an array of nozzles with a resolution of 300 dpi, every other nozzle may be used (150 dpi printing) such that the nozzles 51a to be used may be switched. By spreading the use time of the nozzles 51a in this manner, the lifetime can be further extended.
As described above, according to the first embodiment, printing conditions are changed at predetermined time intervals. With this, it is possible to balance (distribute) the ejection count of each of the nozzles 51a. Thereby, the time for which printing is suspended due to the maintenance of the print head 51 is reduced. As a result, it is possible to suppress a decrease in productivity due to the suspension of printing. Further, since the drive elements of the nozzles 51a are used in a decentralized manner, the drive elements of the print heads 51 can be more uniformly used, which prevents a drive element of specific one of the nozzles 51a from reaching the end of its lifetime earlier than others. Accordingly, the print heads 51 can be used for a longer time. This reduces the frequency of maintenance that requires the replacement of the print head 51 at least due to failure of a drive element or the like, thereby reducing the maintenance time. Thus, it is possible to suppress a decrease in productivity due to the suspension of printing caused by the maintenance of the print head.
Besides, in the nozzles 51a used at low frequency, ink is thickened, or solid matter is precipitated, which tends to result in that the ink is not properly ejected from the nozzles 51a. However, since the nozzles 51a are used in a decentralized manner, the number of the nozzles 51a used at low frequency decreases, which reduces the frequency of maintenance for solving the problem that ink is not properly ejected from the nozzles 51a. Meanwhile, ink adheres to the periphery of the nozzles 51a used at high frequency, which causes liquid pooling and thus prevents proper ejection of the ink. However, since the nozzles 51a are used in a decentralized manner, the number of the nozzles 51a used at high frequency decreases, which reduces the frequency of maintenance for solving the problem of liquid pooling around the nozzles 51a. Thereby the maintenance time can be reduced. Thus, it is possible to suppress a decrease in productivity due to the suspension of printing caused by the maintenance of the print head.
Next, a second embodiment will be described with reference to
In the first embodiment described above, an example is described in which printing conditions are changed at predetermined time intervals during the printing process on the tablets T. Meanwhile, according to this embodiment, optimal printing conditions are set instead of that.
As illustrated in
As illustrated in
The control device 90 sets printing condition based on the optimal print data rotation angle and starts the printing process. Since the optimal printing condition is the condition under which the nozzles 51a can be used most uniformly, it is possible to balance the ejection count of each of the nozzles 51a. Thereby, the time for which printing is suspended due to the maintenance of the print head 51 is reduced. As a result, it is possible to suppress a decrease in productivity due to the suspension of printing. Although described as being selected or set by the control device 90 based on the optimal print data rotation angle, the printing condition may be set in consideration of the results obtained by an external host computer, a local arithmetic device, or the like, or may be set by the operator.
Further, when printing process is performed under optimal printing condition, the optimal printing condition may be switched to relatively suitable printing condition after a predetermined time has elapsed (at predetermined intervals). For example, in the case of the print data rotation angle of 30 degrees (see
Besides, it does not necessarily require a combination of suitable printing condition and optimal printing condition. In order to use the nozzles 51a even just a little more uniformly, the print data rotation angle can be changed periodically (at predetermined intervals). As an example, the print data rotation angle of a print pattern “XYZ 789” is changed by 180 degrees. For example, when the print data rotation angle is 0 degrees, there is a difference between the pattern of ejection counts for “XYZ” and that for “789” as illustrated in
Further, since the nozzles 51a are used in a decentralized manner, the number of the nozzles 51a used at high frequency decreases, which reduces the frequency of maintenance for solving the problem that the nozzles 51a cannot properly eject ink (clogged) as in the first embodiment.
In the above embodiments, the conveyor belt 21 is described as having a plurality of suction ports 21a; however, this is by way of example and not limitation. The conveyor belt 21 may be provided with a slit formed along the conveying direction A1 instead of the suction ports 21a.
In the above embodiments, the tablets T are described as being sequentially supplied from the supply device 10 onto the conveyor belt 21 not at regular intervals but at random; however, this is by way of example and not limitation. For example, the tablets T may be supplied to recesses (pockets) formed regularly in the conveyor belt 21.
In the above embodiments, the tablets T are described as being conveyed by the conveyor belt 21 in two rows; however, this is by way of example only. There may be one row, three rows, or four or more rows, and the number of rows is not particularly limited. Besides, although an example is described in which each of the print heads 51 performs printing on one row of tablets T, it is not so limited. For example, there may be provided one print head 51 on two or more rows of tablets T. Further, there may be provided a plurality of conveyor belts 21.
In the above embodiments, a conveying device that conveys the tablets T while holding them by suction is described as an example of the conveying device 20; however, it is not so limited, and a variety of conveying mechanisms can be used.
In the above embodiments, an example is described in which the timing of printing is determined based on the detection signal from the detecting device 30; however, it is not so limited. For example, the timing of printing may be determined based on the imaging of the imaging device 40.
In the above embodiments, the storage 93 of the control device 90 is described as storing five pieces of print data, i.e., 0° print data, 15° print data, 30° print data, and 45° print data, obtained by rotating a print pattern such as characters, letters, or marks; however, this is by way of example only, and there may be any number of pieces of print data. Note that, as the variation of the print data rotation angle increases, more optimal printing conditions can be found, which is favorable. As described above, the conditions are found by experiments or the like. The control device 90 may obtain the number of nozzles to be used with respect to each of different print data rotation angles based on the print data, the locations of the nozzles, and the like to set printing condition based on a print data rotation angle at which the largest number of nozzles are used.
As an example of a tablet on which printing can be performed without considering the directionality, the tablet T is described as being completely circular in plan view. However, the tablet need not necessarily be completely circular to satisfy this condition. Any tablet can be used as long as printing can be performed thereon without considering its orientation.
For example, the control device 90 may store only print data of a single reference angle, for example, a print pattern (reference data) having a print data rotation angle of 0 degrees in the storage 93, and obtain rotated print data each time to change printing condition. However, as described in the above embodiments, if a plurality of pieces of print data are stored in advance, printing condition can be easily changed, and also the time required for printing can be reduced.
In the above embodiments, a print head in which the nozzles 51a are arranged in an array is described as an example of the inkjet print heads 51; however, it is not so limited. For example, a print head in which the nozzles 51a are arranged in a plurality of arrays may be used.
In the above embodiments, the angle of the print pattern is changed at predetermined time intervals; however, it is not so limited, and it may be changed based on the number of tablets on which printing has been performed. The angle of the print pattern may also be changed with respect to each tablet. It suffices if the angle is changed at intervals that suppress an increase in the time for which each of the nozzles 51a are used and the number of times it is used so that the nozzles 51a can be used more uniformly. How the angle is changed is appropriately determined depending on the print pattern.
Besides, ink may accumulate around the nozzles 51a where ejection takes place frequently, while the viscosity of the ink may increase in the nozzles 51a where ejection takes place at low frequency. In either case, the print quality decreases due to ejection failure such as that the nozzles cannot eject ink in an appropriate amount or a proper direction. Therefore, it is necessary to perform maintenance such as the cleaning of the nozzles 51a before such situations arise. Since the nozzles 51a are used uniformly, it takes more time until the above situations occur. Thus, the frequency of maintenance can be reduced. Therefore, the switching may be performed at intervals taking into account such ejection failure.
The above-described tablets may include tablets for pharmaceutical use, edible use, cleaning, industrial use, and aromatic use. Examples of the tablets include plain tablets (uncoated tablets), sugar-coated tablets, film-coated tablets, enteric coated tablets, gelatin coated tablets, multilayered tablets, dry-coated tablets, and the like. Examples of the tablet further include various capsule tablets such as hard capsules and soft capsules. Although the tablets are described as being completely circular in plan view, the shape is not so limited. Any tablet can be used as long as printing can be performed thereon without considering the directionality. Further, although the tablets are described as having no split line, the embodiments can be applied to printing on those having a split line on one side if printing is performed on the other side without considering the directionality.
In the case where tablets to be printed are for pharmaceutical use or edible use, edible ink is suitably used. Specifically, edible pigments such as Amaranth, Erythrosine, New Coccine (red), Tartrazine, Sunset Yellow FCF, β-Carotene, Crocin (yellow), Brilliant Blue FCF, Indigo Carmine (blue), or the like are dispersed or dissolved in a vehicle, and, if necessary, a pigment dispersant (surfactant) is blended therein, the resultant of which can be used. As the edible ink, any of synthetic dye ink, natural color ink, dye ink, and pigment ink may be used.
In the above embodiments, an example is described in which printing is performed on one side of the tablets T. However, if there is no need to consider the directionality for printing on both the front and back sides of the tablets T, the embodiments can be applied to printing on both the front and back sides by using two apparatuses illustrated in
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-195009 | Sep 2016 | JP | national |
| 2016-196101 | Oct 2016 | JP | national |
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| 20040263545 | Esaki et al. | Dec 2004 | A1 |
| 20110128557 | Kinoshita et al. | Jun 2011 | A1 |
| 20120132722 | Ackley, Jr. et al. | May 2012 | A1 |
| 20170259595 | Aoyagi et al. | Sep 2017 | A1 |
| Number | Date | Country |
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| 7-81050 | Mar 1995 | JP |
| 2005-22114 | Jan 2005 | JP |
| WO2009025371 | Feb 2009 | JP |
| 5281009 | Sep 2013 | JP |
| 2015-166053 | Sep 2015 | JP |
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| Entry |
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| International Search Report dated Nov. 14, 2017 in PCT/JP2017/033638 filed Sep. 19, 2017. |
| Number | Date | Country | |
|---|---|---|---|
| 20190217631 A1 | Jul 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2017/033638 | Sep 2017 | US |
| Child | 16368532 | US |
