JP2020044290A - Ink feeding part, printer, tablet printer and ink pouch - Google Patents

Abstract

To perform printing consecutively by suppressing the frequency of suspension of printing processing for charging ink and the like to the low level.SOLUTION: An ink feeding unit (ink feeding part) 50 is provided in a tablet printer (printer) for performing printing in an ink jet method on a surface of a tablet (recording medium) 9, and includes a recording head 21 and an ink pouch holding part 51. The recording head 21 includes a discharge surface 210 where a plurality of ink nozzles 211 for discharging ink droplets are arranged. The ink pouch holding part 51 can be connected to the recording head 21 and hold an ink pouch sealing ink fed to the recording head 21 in a soft packaging material. The recording head 21 and the ink pouch holding part 51 are positioned and arranged so that the difference between the position in the vertical direction of the discharge surface 210 and the liquid level position in the vertical direction of the ink sealed in the ink pouch is within a prescribed allowable range.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ink supply unit, a printing device, a tablet printing device, and an ink pouch.

  2. Description of the Related Art Conventionally, a recording head having an ejection surface on which a plurality of ink nozzles for ejecting ink droplets are arranged, and an ink tank for storing ink to be supplied to the recording head are mounted on the same carriage. A printing apparatus that performs printing while integrally moving the printer and the printer is widely known as an on-carriage printing apparatus. Such an on-carriage type printing apparatus is advantageous in that the structure is simple and the ink nozzles are hardly affected by disturbance.

  However, in order to discharge ink droplets with high precision and to perform clean printing, it is necessary to appropriately maintain the meniscus in each ink nozzle. It is necessary to keep the difference between the vertical position of the liquid surface of the ink in the tank and the position in the vertical direction (hereinafter, sometimes referred to as “head difference”) within a predetermined range. For this purpose, conventionally, a range allowed as the height of the ink level in the ink tank is set in advance, and if the ink level falls below the lower limit, measures such as refilling the ink to the upper limit are taken. Had been taken. Therefore, the printing process is often interrupted due to ink replenishment, and it has been difficult to continuously print.

  To cope with such a problem, a printing device as disclosed in Patent Document 2 has been devised. The printing device described in Patent Literature 2 includes an inkjet head (recording head), an ink tank, and a moving device. The moving device described in Patent Literature 2 maintains the head difference between the height of the ink surface in the ink tank and the nozzle formation surface (ejection surface) where the nozzles are formed at a preset value. It is stated that the height of the ink tank is changed based on the amount of ink used which is grasped in advance.

  According to the printing apparatus described in Patent Literature 2, by changing the height of the ink tank, the head difference can be maintained within an allowable range for a long period of time, and the printing process is interrupted due to ink replenishment or the like. It is considered possible to reduce the frequency of occurrence. However, the printing apparatus described in Patent Literature 2 is disadvantageous in that it has a moving apparatus, so that the apparatus becomes large-sized, and that the influence of disturbance in the ink nozzles is large.

International Publication No. WO 2016/159096

  The present invention has been made in view of the above circumstances, and a potential purpose thereof is to enable continuous printing while suppressing the frequency of interruption of a printing process for replenishing ink or the like. It is in.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  According to a first aspect of the present application, there is provided an ink supply unit provided in a printing apparatus that performs printing on a surface of a recording medium by an inkjet method, the ink supply unit including a recording head and an ink pouch holding unit. . The recording head has an ejection surface on which a plurality of ink nozzles for ejecting ink droplets are arranged. The ink pouch holding section is connectable to the recording head, and is capable of holding an ink pouch in which ink to be supplied to the recording head is sealed in a soft packaging material. In the ink supply unit, the recording is performed such that the difference between the vertical position of the ejection surface and the liquid surface position of the ink sealed in the ink pouch in the vertical direction is within a predetermined allowable range. The head and the ink pouch holder are positioned and arranged.

  According to a second aspect of the present invention, in the ink supply unit according to the first aspect, the ink pouch holding unit has a mounting bottom surface that receives the ink pouch from below.

  According to a third aspect of the present invention, in the ink supply unit according to the second aspect, the ink pouch holding unit has a pair of side surfaces extending vertically upward from the placement bottom surface. The ink pouch is sandwiched between the pair of side surfaces from both sides.

  According to a fourth aspect of the present invention, in the ink supply unit according to the second aspect or the third aspect, the ink pouch holding unit further includes a discharge port for discharging ink in the ink pouch toward the recording head. Prepare. The mounting bottom surface has an inclined plane shape that gradually lowers vertically as approaching the outlet.

  According to a fifth aspect of the present invention, in the ink supply unit according to the fourth aspect, the inclination angle of the bottom surface is 5 ° or more and 15 ° or less with respect to a horizontal direction.

  According to a sixth aspect of the present invention, in the ink supply unit according to the fifth aspect, the inclination angle of the placing bottom surface is 8 ° or more and 12 ° or less with respect to the horizontal direction.

  According to a seventh aspect of the present invention, in the ink supply unit according to any one of the first to sixth aspects, the ink pouches having different capacities are selectively attached to the ink pouch holding unit. It is possible.

  According to an eighth aspect of the present invention, in the ink supply unit according to any one of the first aspect to the seventh aspect, the recording head is supported at one end and the ink pouch is held at the other end. The device further includes a support member on which the portion is supported.

  According to a ninth aspect of the present invention, in the ink supply unit according to the eighth aspect, a piping for supplying the ink in the ink pouch to the recording head is further provided.

  According to a tenth aspect of the present invention, in the ink supply unit according to the ninth aspect, a unit including the recording head, the ink pouch holding unit, the support member, and the pipe includes another unit of the printing apparatus. It can be integrally attached to and detached from the configuration.

  According to an eleventh aspect of the present invention, there is provided a printing apparatus including the ink supply unit according to any one of the first to tenth aspects.

  According to a twelfth aspect of the present application, there is provided a tablet printing apparatus that includes an ink supply unit according to any one of the first to tenth aspects and performs printing on a surface of a tablet as the recording medium by an inkjet method. Provided.

  According to a thirteenth aspect of the present application, there is provided an ink pouch attached to the ink pouch holding part of the ink supply part according to any one of the first to tenth aspects. This ink pouch is provided with a pouch opening at an end on the vertically lower side for discharging the ink inside. A vertically lower side of the ink pouch has an inclined shape that gradually lowers vertically as approaching the pouch opening.

  According to the first to thirteenth aspects of the present application, continuous printing can be performed while suppressing the frequency of interruption of the printing process for replenishing ink and the like.

  In particular, according to the first aspect of the present application, when ink is consumed by performing printing, the thickness of the ink pouch in the horizontal direction gradually decreases. Therefore, even if the ink is consumed, the liquid level position of the ink in the ink pouch does not change significantly. Therefore, even if the printing process proceeds, the difference between the liquid level position in the vertical direction of the ink in the ink pouch and the vertical position of the ejection surface can be appropriately maintained for a long time. As a result, it is possible to perform printing continuously without reducing the frequency of interruption of the printing process for replenishing ink and the like. In addition, since the ink supply unit of this configuration is of an on-carriage type, the influence of disturbance on the ink nozzles can be reduced.

  In particular, according to the third aspect of the present invention, the ink pouch is received from below on the mounting bottom surface and is sandwiched between both sides by a pair of side surfaces, so that the thickness of the ink pouch in the horizontal direction is reduced as ink is consumed. It becomes easy to gradually reduce the thickness. Thus, even if the ink is consumed, the liquid level position of the ink in the ink pouch does not change much.

  In particular, according to the fourth aspect of the present invention, the manner in which the ink level in the ink pouch in the vertical direction decreases as the ink is consumed becomes more gentle. Therefore, the difference between the liquid level position in the vertical direction of the ink in the ink pouch and the vertical position of the ejection surface can be kept within an allowable range for a longer period of time. As a result, the frequency of interruption of the printing process for ink replenishment or the like can be suppressed less, and continuous printing can be performed. Further, since the movement of the ink to the discharge port side in the ink pouch can be promoted, when the amount of the ink in the ink pouch becomes low, the remaining ink is less likely to be divided in the vertical direction.

  In particular, according to the seventh aspect of the present invention, printing can be performed by attaching an ink pouch having an appropriate capacity according to the required amount of ink, and the printing apparatus can be economically operated.

  In particular, according to the eighth aspect of the present invention, the difference between the liquid level position of the ink in the ink pouch in the vertical direction and the position of the ejection surface in the vertical direction is kept within an allowable range in advance. It is easy to dispose it in a positioned state.

  In particular, according to the ninth aspect of the present invention, the difference between the liquid surface position of the ink in the ink pouch in the vertical direction and the position of the ejection surface in the vertical direction is kept within an allowable range. The ink can be supplied to the ink nozzles using the head difference without providing a pump or the like.

  In particular, according to the tenth aspect of the present invention, it is possible to unitize and handle the ink supply unit in a state where the vertical relation between the position of the ejection surface and the position of the ink pouch holding unit is properly set. Becomes possible. Therefore, for example, by preparing such a unit in advance for each different type of ink in advance, and by detaching and attaching the unit, it is easy to use a plurality of types of inks for printing.

  In particular, in the thirteenth aspect of the present application, the manner in which the ink level in the ink pouch in the vertical direction is gradually decreased due to the consumption of the ink. Therefore, the difference between the liquid level position in the vertical direction of the ink in the ink pouch and the vertical position of the ejection surface can be kept within an allowable range for a longer period of time. As a result, the frequency of interruption of the printing process for ink replenishment or the like can be suppressed less, and continuous printing can be performed. Further, since the movement of the ink to the discharge port side in the ink pouch can be promoted, when the amount of the ink in the ink pouch becomes low, the remaining ink is less likely to be divided in the vertical direction.

It is a figure showing the schematic structure of the tablet printing device. It is a partial perspective view of a tablet conveyance mechanism. It is a bottom view of a head. It is a side view of an ink supply part. It is a side view of an ink pouch.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a direction in which a plurality of tablets are transported is referred to as a “transport direction”, and a direction perpendicular and horizontal to the transport direction is referred to as a “width direction”.

<1. Overall Configuration of Tablet Printing Device>
FIG. 1 is a diagram showing a configuration of a tablet printing apparatus (printing apparatus) 1 according to an embodiment of the present invention. The tablet printing apparatus 1 is an apparatus that prints an image such as a product name, a product code, a company name, and a logo mark on the surface of each tablet 9 while transporting a plurality of tablets 9 as medicines. As shown in FIG. 1, the tablet printing apparatus 1 of the present embodiment includes a tablet transport mechanism 10, a printing unit 20, a drying mechanism 30, and a control unit 40.

  The tablet transport mechanism 10 is a mechanism that transports a plurality of tablets 9 while holding them. The tablet transport mechanism 10 has a pair of pulleys 11 and an annular transport belt 12 stretched between the pair of pulleys 11. The plurality of tablets 9 supplied to the tablet printing apparatus 1 are arranged at equal intervals by a carry-in mechanism 91 including a vibration feeder and a transport drum, and are supplied to the outer peripheral surface of the transport belt 12. One of the pair of pulleys 11 is rotated by power obtained from the transport motor 13. Thereby, the transport belt 12 rotates in the direction of the arrow in FIG. At this time, the other of the pair of pulleys 11 is driven to rotate with the rotation of the transport belt 12.

  FIG. 2 is a partial perspective view of the tablet transport mechanism 10. As shown in FIG. 2, the transport belt 12 is provided with a plurality of suction holes 14. The plurality of suction holes 14 are arranged at equal intervals in the transport direction and the width direction. Further, as shown in FIG. 1, the tablet transport mechanism 10 has a suction mechanism 15 that sucks gas from a space inside the transport belt 12. When the suction mechanism 15 is operated, the space inside the conveyor belt 12 has a negative pressure lower than the atmospheric pressure. The plurality of tablets 9 are sucked and held in the suction holes 14 by the negative pressure.

  As described above, the tablet transport mechanism 10 transports the plurality of tablets 9 by rotating the transport belt 12 while holding the plurality of tablets 9 in the plurality of suction holes 14 at fixed intervals. Below the four recording heads 21 described below, the plurality of tablets 9 are transported in the horizontal direction.

  Further, as shown in FIG. 1, the tablet transport mechanism 10 has a blow mechanism 16 inside the transport belt 12. When the blow mechanism 16 is operated, only the suction holes 14 facing the unloading mechanism 92 among the plurality of suction holes 14 of the conveyor belt 12 have a positive pressure higher than the atmospheric pressure. Thereby, the suction of the tablets 9 in the suction holes 14 is released, and the tablets 9 are delivered from the conveyor belt 12 to the unloading mechanism 92. The unloading mechanism 92 unloads the tablets 9 delivered from the transport belt 12 to the outside of the tablet printing apparatus 1 by another transport belt, for example.

  The printing unit 20 is a part that records an image on the surface of the tablet 9 transported by the transport belt 12 by an inkjet method. As shown in FIG. 1, the printing unit 20 of the present embodiment has four recording heads 21. Each recording head 21 is included in an ink supply unit 50 described later. The four recording heads 21 are located above the transport belt 12 and are arranged in a line along the transport direction of the tablets 9. The four recording heads 21 eject ink droplets of different colors (for example, cyan, magenta, yellow, and black) toward the surface of the tablet 9. Then, a multicolor image is recorded on the surface of the tablet 9 by superimposing the single color images formed by these colors. The ink ejected from each recording head 21 is an edible ink manufactured from a material approved by the Japanese Pharmacopoeia, the Food Sanitation Law, or the like.

  FIG. 3 is a bottom view of one recording head 21. In FIG. 3, the transport belt 12 and the plurality of tablets held on the transport belt 12 are indicated by two-dot chain lines. As shown in an enlarged manner in FIG. 3, a plurality of ink nozzles 211 capable of ejecting ink droplets are provided on an ejection surface 210 which is a lower surface of the recording head 21. In the present embodiment, a plurality of ink nozzles 211 are two-dimensionally arranged on the lower surface of the recording head 21 in the transport direction and the width direction. The ink nozzles 211 are arranged with their positions shifted in the width direction. In this way, if the plurality of ink nozzles 211 are two-dimensionally arranged, the positions of the ink nozzles 211 in the width direction can be made closer to each other. However, the plurality of ink nozzles 211 may be arranged in a line along the width direction.

  As a method of ejecting ink droplets from the ink nozzle 211, for example, a so-called piezo method is used in which a piezoelectric element, which is a piezoelectric element, is deformed by applying a voltage to pressurize and eject ink in the ink nozzle 211. . However, the method of discharging ink droplets may be a so-called thermal method in which the heater is energized to discharge ink by heating and expanding the ink in the ink nozzle 211.

  The drying mechanism 30 is a mechanism for drying the ink attached to the surface of the tablet 9. The drying mechanism 30 is provided around the transport belt 12 at a position downstream of the printing unit 20 in the transport direction. As the drying mechanism 30, for example, a hot air supply mechanism that blows heated gas (hot air) toward the tablets 9 conveyed by the conveyor belt 12 is used. The ink attached to the surface of the tablet 9 is dried by hot air and fixed on the surface of the tablet 9.

  The control unit 40 is a unit for controlling the operation of each unit in the tablet printing apparatus 1. The control unit 40 is configured by a computer having a processor such as a CPU, a memory such as a RAM, and a storage unit such as a hard disk drive. A computer program for executing a printing process is installed in the storage unit of the control unit. The control unit 40 is communicably connected to the transport motor 13, the suction mechanism 15, the blow mechanism 16, the four recording heads 21, the drying mechanism 30, the carry-in mechanism 91, and the carry-out mechanism 92. The control unit 40 is also communicably connected to a vertical movement mechanism 62 and a horizontal movement mechanism 64, which will be described later. The control unit 40 temporarily reads out the computer programs and data stored in the storage unit into a memory, and executes a calculation process by a processor based on the computer program. The operation of each part is controlled. Thereby, the printing process for the plurality of tablets 9 proceeds.

<2. Details of the printing section>
FIG. 4 is a side view of the printing unit 20 as viewed from the position of the white arrow V in FIG. As shown in FIG. 4, the internal space of the tablet printing apparatus 1 is divided into a printing area A1 and a maintenance area A2. The printing area A1 is an area where printing is performed on the tablet 9 while the tablet 9 is transported by the tablet transport mechanism 10 described above. The maintenance area A2 is an area where the recording head 21 is put on standby before or after printing, the ejection surface 210 of the recording head 21 is cleaned, and an ink supply unit 50 described later is replaced. A partition 95 is provided between the print area A1 and the maintenance area A2 to partition both areas. The partition wall 95 extends parallel to the transport direction of the tablet 9 and perpendicular to the horizontal plane.

  As described above, the printing unit 20 has four recording heads 21. Further, as shown in FIG. 4, the printing unit 20 has an ink supply unit 50 for each recording head 21. Note that the ink supply unit 50 also includes the recording head 21 itself. The printing unit 20 includes an ink supply unit moving mechanism 60 corresponding to each recording head 21 (ink supply unit 50), and four cleaning units 71 corresponding to each recording head 21.

<2-1. About ink supply unit>
The ink supply unit 50 supplies ink to the printing unit 20. As described above, the ink supply unit 50 is provided for each recording head 21. The ink supply unit 50 includes an ink pouch holding section 51, a joint section 52, a support member 53, and a pipe 54 in addition to the recording head 21.

  The ink pouch holding unit 51 is a holder that can hold an ink pouch 110 in which ink to be supplied to the recording head 21 is sealed in a soft packaging material. The ink pouch holding section 51 is connectable to the recording head 21. More specifically, the ink pouch holding section 51 mainly has a mounting bottom surface 510, a pair of side surfaces 512 and 513, and a discharge port 514.

  The pair of side surfaces 512 and 513 are plate-like portions extending vertically upward from the mounting bottom surface 510. The pair of side surfaces 512 and 513 are arranged so as to form a plane perpendicular to the transport direction. Of the pair of side surfaces 512 and 513, a concave portion 512a along the shape of the ink pouch 110 is provided on the side surface 512 on the upstream side in the transport direction. On the other hand, the side surface 513 on the downstream side in the transport direction has a lid shape capable of covering the concave portion 512a.

  The mounting bottom surface 510 forms a surface below the concave portion 512a. The placement bottom surface 510 is a plate-shaped portion that receives the ink pouch 110 accommodated in the ink pouch holder 51 from below. The mounting bottom surface 510 has an inclined plane shape that gradually lowers vertically as approaching a discharge port 514 described later. The inclination angle of the mounting bottom surface 510 with respect to the horizontal direction is preferably 5 ° or more and 15 ° or less, more preferably 8 ° or more and 12 ° or less, and even more preferably 10 °. The mounting bottom surface 510 has a thin shape in the transport direction.

  The side surface 513 is detachable from the side surface 512 with a fastening member such as a screw. By attaching the side surface 513 to the side surface 512 while the ink pouch 110 is housed in the concave portion 512a, the ink pouch 110 can be held in the ink pouch holding portion 51.

  The discharge port 514 is a cylindrical portion that discharges the ink in the ink pouch 110 toward the recording head 21. One end of the discharge port 514 is connected to a vertically lower end of the concave portion 512a and near a position where the mounting bottom surface 510 is lowest. The other end of the outlet 514 is located closer to the recording head 21 than one end of the outlet 514.

  One end of the joint 52 is connected to the other end of the outlet 514. The other end of the joint part 52 is connected to a pipe 54. The pipe 54 is a pipe that connects the other end of the joint 52 to the ink nozzle 211 of the recording head 21. Thereby, the pipe 54 can supply the ink in the ink pouch 110 to the recording head 21.

  The support member 53 has a plate shape perpendicular to the transport direction, and has a shape that is long in the width direction. The recording head 21 is supported at one end of the support member 53 in the width direction. An ink pouch holder 51 is supported at the other end of the support member 53 in the width direction. More specifically, the recording is performed such that the difference between the vertical position of the ejection surface 210 of the recording head 21 and the liquid surface position of the ink sealed in the ink pouch 110 in the vertical direction is within a predetermined allowable range. The head 21 and the ink pouch holder 51 are positioned and fixed to the support member 53. In other words, when the ink pouch 110 is attached to the ink pouch holding unit 51, the head difference between the liquid surface position in the ink pouch 110 and the liquid surface position of the ink on the ejection surface 210 is The relative position in the vertical direction between the recording head 21 and the ink pouch holding unit 51 is determined by the support member 53 so that the head difference is such that a proper meniscus can be held in each ink nozzle 211. I have.

  The combination of the recording head 21, the ink pouch holding section 51, the joint section 52, the support member 53, and the pipe 54 is unitized as an ink supply unit 50. That is, the ink supply unit 50 can be integrally attached to and detached from other components of the tablet printing apparatus 1. In the present embodiment, such an ink supply unit 50 is prepared in advance for each type of ink. Thus, by replacing the ink supply unit 50 by attaching and detaching the ink supply unit 50, a plurality of types of ink can be selectively used for printing.

<2-2. About Ink Pouch>
An ink pouch 110 shown in FIG. 5 is an ink supply source held by the ink pouch holding unit 51 described above. That is, in the present invention, the ink pouch 110 is used as an ink supply source instead of the conventional ink tank. FIG. 5 is a side view showing the configuration of the ink pouch 110.

  The ink pouch 110 is obtained by enclosing ink in a soft packaging material. The ink pouch 110 can be easily deformed in a direction in which the front surface and the back surface approach and separate from each other. When viewed from the posture when the ink pouch 110 is attached to the ink pouch holding portion 51, a pouch opening 111 for discharging (discharging) the ink inside is provided at the vertically lower end of the ink pouch 110. I have. The ink pouch 110 has a thin shape in the transport direction, and has a trapezoidal shape when viewed in the transport direction. A vertically lower side 112 of the ink pouch 110 is inclined so as to gradually lower vertically as approaching the pouch opening 111.

<2-3. About the mechanism for moving the ink supply unit>
Referring back to FIG. The ink supply unit moving mechanism 60 is a mechanism that moves the ink supply unit 50 between the print area A1 and the maintenance area A2. In other words, the ink supply unit moving mechanism 60 is a mechanism that moves the recording head 21 in an on-carriage manner from the printing area A1 to the maintenance area A2. The ink supply unit moving mechanism 60 of the present embodiment has an arm 61, a vertical moving mechanism 62, a moving stage 63, and a horizontal moving mechanism 64. The arm 61 is a member extending in the width direction. The recording head 21 is fixed to the tip of the arm 61.

  The vertical movement mechanism 62 moves the arm 61 up and down according to a command from the control unit 40. Thereby, as indicated by an arrow D1 in FIG. 4, the arm 61 and the ink supply unit 50 including the recording head 21 move up and down integrally. Thereby, the position of the ejection surface 210 in the vertical direction can be adjusted according to the thickness of the tablet 9 to be printed. In the maintenance area A2, the cleaning unit 71 can also act on the ejection surface 210 of the recording head 21 by lowering the recording head 21 by the vertical movement mechanism 62. Thereby, the discharge surface 210 can be cleaned and maintenance can be performed.

  The vertical moving mechanism 62 is supported by a moving stage 63. The horizontal moving mechanism 64 moves the moving stage 63 in the width direction. As a result, the moving stage 63, the vertical moving mechanism 62, the arm 61, and the ink supply unit 50 move in the width direction integrally as shown by the arrow D2 in FIG. As the horizontal moving mechanism 64 and the vertical moving mechanism 62, for example, a mechanism that converts the rotational motion of the motor into a linear motion via a ball screw is used. However, the horizontal moving mechanism 64 and the vertical moving mechanism 62 may be realized by another mechanism such as a linear motor or an air cylinder.

  In the tablet printing apparatus 1 configured as described above, the ink supply unit 50 is mounted on the printing unit 20 by attaching the recording head 21 and the support member 53 to the arm 61. Then, the ink pouch 110 can be attached to the ink pouch holding portion 51 in a state where the recording head 21 is moved from the position above the transport belt 12 to the position farthest in the width direction by the horizontal moving mechanism 64. It is. Accordingly, a space where the operator performs the mounting operation can be sufficiently secured at a position away from the conveyor belt 12 in the width direction.

  The attachment of the ink pouch 110 to the ink pouch holding section 51 is performed as follows. That is, first, the operator removes the side surface 513 from the ink pouch holder 51 by removing the fastening member. Then, the operator fits the ink pouch 110 into the concave portion 512a while keeping the pouch opening 111 of the ink pouch 110 connected to the discharge port 514. At this time, the vertically lower side 112 of the ink pouch 110 is received by the mounting bottom surface 510 from below. In this state, the operator attaches the side surface 513 to the side surface 512 by retightening the fastening member. As a result, the ink pouch 110 is sandwiched between the pair of side surfaces 512 and 513 from both sides.

  Then, the ink is supplied to each ink nozzle 211 via the joint 52 and the pipe 54 by the water pressure from the ink pouch 110. At this time, in the ink supply unit 50, the relative position in the vertical direction between the position of the ejection surface 210 and the position of the ink pouch holding portion 51 is appropriately set, so that the ink droplets drip from the ejection surface 210. There is no danger. That is, in each of the ink nozzles 211, an appropriate meniscus is held. Moreover, since the vertical relationship between the position of the ejection surface 210 and the position of the ink pouch holding unit 51 is appropriately set, the ink flows backward from the recording head 21 toward the ink pouch 110, It is difficult for air to enter the recording head 21.

  With the above configuration, in the tablet printing apparatus 1 of the present embodiment, the difference between the liquid level position of the ink in the ink pouch 110 in the vertical direction and the position of the ejection surface 210 in the vertical direction is kept within an allowable range. Therefore, the ink can be supplied to the ink nozzle 211 by utilizing the head difference without providing a pump or the like in the middle of the pipe 54.

  When printing is performed, the recording head 21 is arranged at a position above the transport belt 12 by the horizontal moving mechanism 64, and a voltage is applied to the above-described piezo element according to a command from the control unit 40. Then, an ink droplet is ejected from the ink nozzle 211.

  Here, when ink droplets are consumed by the ink nozzles 211 by performing printing, the thickness of the ink pouch 110 in the horizontal direction gradually decreases. More specifically, since the upper surface of the ink pouch 110 gradually becomes closer to the front surface and the back surface of the soft pouch material, the thickness of the ink pouch 110 in the horizontal direction becomes thinner as the amount of ink consumption increases. Therefore, even if the ink is consumed, the liquid level position of the ink in the ink pouch does not change significantly. That is, if a general ink tank is used as the ink supply source, the ink level in the ink tank linearly decreases as the ink is consumed, but as in the present embodiment, the ink supply source is the ink supply source. When the pouch 110 is used, the speed at which the liquid level of the ink descends is slow. Therefore, even if the printing process proceeds, the head difference between the ink surface in the ink pouch 110 and the ejection surface 210 can be maintained within an allowable range for a long period of time. As a result, the printing process does not need to be frequently interrupted for ink replenishment and the like, and printing can be performed efficiently.

  In particular, the vertically lower side 112 of the ink pouch 110 according to the present embodiment has a shape that is lowered vertically lower as it approaches the pouch opening 111. More specifically, the ink pouch 110 is tapered downward, and the amount of stored ink decreases toward the bottom. Therefore, the liquid surface position of the ink when the remaining amount of ink is the same is higher than when an ink pouch having a tapered lower portion is not used. Therefore, the time during which the liquid level of the ink is maintained at a height at which the above-mentioned head difference is within the allowable range can be made longer. Therefore, even if the printing process proceeds, the head difference between the ink surface in the ink pouch 110 and the ejection surface 210 can be appropriately maintained for a long time. In addition, the shape of the side 112 and the placement bottom surface 510 can facilitate the movement of the ink toward the outlet 514 in the ink pouch 110. In FIG. 5, the direction in which the ink moves is indicated by a white arrow. For this reason, when the amount of ink remaining in the ink pouch 110 is low, it is less likely that the remaining ink will be divided in the vertical direction.

  When the remaining amount of ink in the ink pouch 110 becomes low, the side 513 of the ink pouch holding portion 51 can be attached and detached and replaced with a new ink pouch 110 by the same method as described above.

  By the way, the tablet printing apparatus 1 of the present embodiment can be used for printing on a plurality of types of tablets 9 having different surface coating materials. When printing on tablets 9 having different surface coating materials, the type of ink to be used for printing generally differs. Therefore, in the tablet printing apparatus 1, it is necessary to use a plurality of types of inks in accordance with the type of the tablet 9 to be printed. In this regard, in the tablet printing apparatus 1 of the present embodiment, the ink supply unit 50 for one type of ink is detached from the arm 61, and the ink supply unit 50 for another type of ink is newly attached to the arm 61. In addition, the ink can be easily used properly. At this time, in order to prevent the ink from being mixed, there is no need to put a cleaning liquid or the like in the joint portion 52 or the pipe 54 for cleaning, so that the labor and burden of the operator and the time and cost required for maintenance are greatly reduced. .

  As described above, the ink supply unit (ink supply unit) 50 of the present embodiment includes the recording head 21 and the ink pouch holding unit 51. Then, the recording head 21 and the ink pouch are adjusted so that the difference between the vertical position of the ejection surface 210 and the liquid surface position of the ink sealed in the ink pouch 110 in the vertical direction is within a predetermined allowable range. The holding unit 51 is positioned and arranged. In the ink supply unit 50 having this configuration, when ink is consumed by performing printing, the thickness of the ink pouch 110 in the horizontal direction gradually decreases. Therefore, even if the ink is consumed, the difference between the liquid level position of the ink in the ink pouch 110 in the vertical direction and the position of the ejection surface 210 in the vertical direction can be appropriately maintained for a long time. As a result, it is possible to perform printing continuously without reducing the frequency of interruption of the printing process for replenishing ink and the like.

  In the ink supply unit 50 of the present embodiment, the ink pouch 110 is received from below by the mounting bottom surface 510 and is sandwiched between the pair of side surfaces 512 and 513 from both sides. This makes it easier to gradually reduce the thickness of the ink pouch 110 in the horizontal direction as the ink is consumed. Thus, even if the ink is consumed, the liquid level position of the ink in the ink pouch does not change much.

  Further, in the ink supply unit 50 of the present embodiment, the placement bottom surface 510 has an inclined plane shape that gradually decreases in the vertical direction as approaching the discharge port 514. The inclination angle of the mounting bottom surface 510 is preferably 5 ° or more and 15 ° or less with respect to the horizontal direction, and more preferably 8 ° or more and 12 ° or less with respect to the horizontal direction. Accordingly, the manner in which the ink level in the ink pouch 110 in the vertical direction decreases as the ink is consumed becomes more gentle. Therefore, the difference between the liquid level position of the ink in the ink pouch 110 in the vertical direction and the position of the ejection surface 210 in the vertical direction can be kept within an allowable range for a longer period. As a result, the frequency of interruption of the printing process for ink replenishment or the like can be suppressed less, and continuous printing can be performed. Further, since the movement of the ink to the discharge port 514 side in the ink pouch 110 can be promoted, when the amount of the ink in the ink pouch 110 decreases, the remaining ink is divided in the vertical direction and the upper part of the ink pouch 110 It is less likely that the situation will be left behind.

  Further, in the ink supply unit 50 of the present embodiment, ink pouches 110 having different capacities can be selectively attached. Accordingly, printing can be performed by attaching the ink pouch 110 having an appropriate capacity according to the amount of ink used, and the printing apparatus can be economically operated.

  Further, in the ink supply unit 50 of the present embodiment, the recording head 21 is supported at one end of the support member 53, and the ink pouch holder 51 is supported at the other end. Thereby, the layout is performed in a pre-positioned state such that the difference between the liquid level position in the vertical direction of the ink in the ink pouch 110 and the vertical position of the ejection surface 210 is kept within an allowable range. It becomes easier.

  Further, the ink supply unit 50 of the present embodiment is integrally detachable from other components of the tablet printing apparatus 1. This makes it possible to integrally handle the ink supply unit 50 in which the vertical relationship between the position of the ejection surface 210 and the position of the ink pouch holding portion 51 is properly set. Therefore, for example, by preparing such an ink supply unit 50 for each different type of ink in advance, and attaching and detaching and replacing the ink supply unit 50, it is easy to use a plurality of types of ink for printing.

<3. About Modifications>
As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various changes may be made to the above-described ones without departing from the gist thereof. It is possible.

  In the above embodiment, the ink pouch 110 has a trapezoidal shape when viewed in the transport direction. However, the present invention is not limited to this. For example, the ink pouch 110 may have a rectangular shape when viewed in the transport direction. In that case, the long side of the rectangular shape of the ink pouch may be placed on the inclined placement bottom surface 510.

  In the above-described embodiment, the ink pouch 110 having different capacities can be selectively attached to the ink pouch holding unit 51, but the present invention is not limited to this. Instead of the above, only the ink pouch 110 having a fixed capacity may be attached to the ink pouch holding section 51.

  In addition, the elements appearing in the above-described embodiments and the modified examples may be appropriately combined as long as no contradiction occurs.

1 tablet printing device (printing device)
9 tablets (recording media)
21 recording head 50 ink supply unit (ink supply unit)
REFERENCE SIGNS LIST 51 ink pouch holder 110 ink pouch 111 pouch opening 112 vertically lower side 210 ejection surface 510 mounting bottom surface 512 side surface 513 side surface 514 discharge port 53 support member 54 piping

Claims (13)

An ink supply unit provided in a printing apparatus that performs printing on a surface of a recording medium by an inkjet method,
A recording head having an ejection surface on which a plurality of ink nozzles for ejecting ink droplets are arranged,
An ink pouch holding unit connectable to the recording head and capable of holding an ink pouch in which the ink to be supplied to the recording head is sealed in a soft packaging material;
With
The recording head and the ink pouch holding unit such that the difference between the vertical position of the ejection surface and the liquid surface position of the ink sealed in the ink pouch in the vertical direction is within a predetermined allowable range. And an ink supply unit where the unit is positioned and arranged. The ink supply unit according to claim 1, wherein:
The ink supply unit, wherein the ink pouch holding unit has a mounting bottom surface that receives the ink pouch from below. The ink supply unit according to claim 2, wherein
The ink pouch holding portion has a pair of side surfaces extending vertically upward from the mounting bottom surface,
An ink supply unit, wherein the ink pouch is sandwiched between the pair of side surfaces from both sides. The ink supply unit according to claim 2 or 3, wherein:
The ink pouch holding section,
A discharge port for discharging ink in the ink pouch toward the recording head,
The ink supply unit, wherein the placement bottom surface is an inclined flat surface that gradually lowers vertically as approaching the discharge port. The ink supply unit according to claim 4, wherein:
The ink supply unit, wherein the inclination angle of the bottom surface is 5 ° or more and 15 ° or less with respect to a horizontal direction. The ink supply unit according to claim 5, wherein
The ink supply unit, wherein the inclination angle of the bottom surface is 8 ° or more and 12 ° or less with respect to a horizontal direction. The ink supply unit according to any one of claims 1 to 6, wherein:
An ink supply unit to which the ink pouches having different capacities can be selectively attached to the ink pouch holding unit. The ink supply unit according to any one of claims 1 to 7, wherein:
An ink supply unit, further comprising a support member having one end supporting the recording head and the other end supporting the ink pouch holding unit. The ink supply unit according to claim 8, wherein:
An ink supply unit further comprising a pipe for supplying the ink in the ink pouch to the recording head. The ink supply unit according to claim 9, wherein:
An ink supply unit, wherein a unit including the recording head, the ink pouch holding unit, the support member, and the pipe is integrally detachable from other components of the printing apparatus.   A printing apparatus, comprising: the ink supply unit according to claim 1.   A tablet printing apparatus comprising the ink supply unit according to any one of claims 1 to 10, and performing printing on a surface of a tablet as the recording medium by an inkjet method. An ink pouch attached to the ink pouch holding section of the ink supply section according to any one of claims 1 to 10, wherein:
Equipped with a pouch opening at the lower end on the vertical side to pour out the ink inside,
An ink pouch in which a vertically lower side of the ink pouch is gradually inclined vertically downward as approaching the pouch opening.

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