TWI742845B - Ink supply unit, printing apparatus, and tablet printing apparatus - Google Patents

Abstract

The ink supply unit, printing device, and tablet printing device of the present invention can suppress the occurrence of printing defects such as printing omissions caused by air bubbles. The ink supply unit (ink supply unit) includes a recording head, an ink pack holding unit, and ink piping. The recording head has an ejection surface, and a plurality of ink nozzles that eject ink droplets are arranged on the ejection surface. The ink pack holding portion can hold an ink pack in which the ink supplied to the recording head is enclosed in a soft packaging material. The ink pack holding portion includes a cylindrical discharge port, and the discharge port discharges the ink in the ink pack to the recording head. The ink pipe is cylindrical, one end is connected to the recording head, and the other end is connected to the discharge port. The discharge port is arranged obliquely with respect to the horizontal direction. The front end of the discharge port faces vertically downward as it moves away from the ink pack.

Description

Ink supply unit, printing device and tablet printing device

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

In the past, an ink supply unit included in a printing device that performs printing on the surface of a recording medium by an ink-jet method has been known. Such an ink supply unit is disclosed in Patent Document 1, for example.

The ink-jet printer described in Patent Document 1 includes: an ink supply needle (3), which supplies ink to the recording head (2) side; and an ink container (1), which contains ink, which supplies ink through The needle (3) pierces the ink container (1) to supply ink from the ink container (1) to the recording head (2) side. The ink container (1) is formed of a soft packaging material, and the ink supply needle (3) can be directly pierced into the ink container (1) to supply ink from the ink container (1) to the recording head (2) side. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-347259

[The problem to be solved by the invention]

However, in the inkjet printer described in Patent Document 1, when the remaining amount of ink in the ink container decreases and the ink container is attached or detached, it is conceivable that air bubbles may be mixed into the ink supply needle. If air bubbles are mixed into the ink supply needle, it is difficult to perform deaeration with a deaeration filter or the like, and the air bubbles may cause printing defects such as missing printing.

The present invention is made in view of the above circumstances, and its object is to suppress the occurrence of printing defects such as printing omissions caused by air bubbles. [Technical means to solve the problem]

The problem to be solved by the present invention is as above. Next, the technical means to solve the problem will be explained.

The first aspect of the present application provides an ink supply unit that is provided in a printing device that performs printing on the surface of a recording medium by an inkjet method. The ink supply unit includes a recording head, an ink pouch holding unit, and ink piping. The recording head has an ejection surface, and a plurality of ink nozzles that eject ink droplets are arranged on the ejection surface. The ink pack holding portion can hold an ink pack in which the ink supplied to the recording head is enclosed in a soft packing material. The ink pack holding portion includes a cylindrical discharge port that discharges the ink in the ink pack to the recording head. The ink pipe has a cylindrical shape, one end is connected to the recording head, and the other end is connected to the discharge port. The discharge port is arranged obliquely with respect to the horizontal direction. The front end of the discharge port faces vertically downward as it moves away from the ink pack.

The second aspect of the present application is based on the ink supply part of the first aspect, wherein the other end of the ink pipe is connected to the front end of the discharge port in a straight line.

The third aspect of the present application is based on the ink supply part of the first or second aspect, wherein the bent portion of the internal flow path switching direction as the midway portion of the ink piping is located closer to the lead than the discharge port. Hang down the side.

The fourth aspect of the present application is based on the ink supply part of the third aspect, wherein the bent part is located on the most vertically downward side of the ink pipe.

A fifth aspect of the present application is based on the ink supply unit according to the third or fourth aspect, wherein the discharge port is located on a vertically lower side than the ejection surface of the recording head.

The sixth aspect of the present application is based on the ink supply part according to any one of the third to fifth aspects, wherein the ink pack holding part has a placement bottom surface that receives the ink pack from below.

The seventh aspect of the present application is based on the ink supply part of the sixth aspect, wherein the ink pack holding part has a pair of side surfaces extending vertically upward from the placement bottom surface. The ink pack is clamped from both sides by the pair of side surfaces.

The eighth aspect of the present application is based on the ink supply part of the sixth aspect or the seventh aspect, wherein the placement bottom surface is in the shape of an inclined plane that gradually descends vertically downward as it approaches the discharge port.

The ninth aspect of the present application is based on the ink supply part of the fifth aspect, wherein the ink pack holding part has a shape longer in the horizontal direction than in the vertical direction.

The tenth aspect of the present application is based on the ink supply part of any one of the first to ninth aspects, and further includes a support member that supports the recording head at one end and supports the ink pack holding part at the other end.

The eleventh aspect of the present application is based on the ink supply section of the tenth aspect, wherein the unit including the recording head, the ink pack holding section, the ink piping, and the support member is compatible with other parts of the printing device The structure is integrally loaded and unloaded.

The twelfth aspect of the present application provides a printing device including the ink supply unit according to any one of the first to the eleventh aspects.

The thirteenth aspect of the present application provides a tablet printing device including the ink supply unit of any one of the first to eleventh aspects, and performs printing on the surface of the tablet as the recording medium by an inkjet method. [Effects of the invention]

According to the first to thirteenth viewpoints of this case, it is possible to suppress the occurrence of printing defects such as printing omissions caused by air bubbles.

In particular, according to the first viewpoint of the present application, air bubbles mixed in the vicinity of the discharge port during loading and unloading of the ink pack easily escape into the ink pack through the discharge port.

In particular, according to the second point of view of the present application, air bubbles mixed in the vicinity of the discharge port during loading and unloading of the ink pack are more likely to escape into the ink pack through the discharge port than the inside of the ink pipe.

In particular, according to the third viewpoint of the present application, air bubbles mixed in the vicinity of the discharge port during loading and unloading of the ink pack are more likely to escape into the ink pack.

In particular, according to the fourth aspect of the present application, air bubbles mixed in the vicinity of the discharge port during loading and unloading of the ink pack are more likely to escape into the ink pack.

In particular, according to the fifth viewpoint of the present application, for example, the difference between the position of the ejection surface in the vertical direction and the position of the liquid surface of the ink enclosed in the ink pack in the vertical direction is within a predetermined allowable range (ideal head difference). , To set the positional relationship between the discharge port and the ejection surface in the vertical direction, so that the meniscus in the ink nozzle can be properly maintained.

In particular, according to the seventh viewpoint of the present case, by using the bottom surface of the mounting surface to receive the ink pack from below, and using a pair of side surfaces to hold the ink pack from both sides, it is easy to make the thickness of the ink pack in the horizontal direction gradually change as the ink is consumed. Thin. Thus, even if the ink is consumed, the position of the ink level in the ink pack does not change much.

In particular, according to the eighth point of view of the present case, the ink in the ink pack can be promoted to move to the side of the discharge port. Therefore, the following situation is not easy to occur. That is, when the ink residue in the ink pack decreases, the remaining ink is vertically Breaking and so on.

In particular, according to the ninth aspect of the present application, the difference between the position of the ejection surface in the vertical direction and the position of the liquid surface of the ink enclosed in the ink pack in the vertical direction can be within a predetermined allowable range (ideal head difference). Equipped with large-capacity ink. As a result, the interruption frequency of the printing process for replenishing ink etc. can be suppressed to be less, and printing can be performed continuously. Furthermore, it is possible to reduce the possibility of air bubbles being mixed with the loading and unloading of the ink pack.

In particular, according to the tenth aspect of the present application, it is easy to arrange the ink in the ink pack in a pre-positioned state so that the difference between the position of the ink in the vertical direction and the position of the ejection surface in the vertical direction is kept within the allowable range. .

In particular, according to the eleventh aspect of the present application, the relative relationship between the position of the ejection surface, the position of the ink pack holding portion, and the position of the ink pipe in the vertical direction can be unitized by an ink supply portion in a state where it is appropriately set. Therefore, by pre-preparing such units for each type of ink, it is possible to print with multiple inks by attaching and detaching the replacement unit.

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

＜1. Overall structure of tablet printing device＞

FIG. 1 is a diagram showing the configuration of a tablet printing device (printing device) 1 according to an embodiment of the present invention. The tablet printing device 1 is a device that prints images such as product name, product code, company name, trademark, etc. on the surface of each tablet 9 while conveying a plurality of tablets 9 as pharmaceuticals. As shown in FIG. 1, the tablet printing apparatus 1 of this embodiment includes a tablet conveying mechanism 10, a printing unit 20, a drying mechanism 30, and a control unit 40.

The lozenge conveying mechanism 10 is a mechanism for conveying a plurality of lozenges 9 while holding them. The lozenge conveying mechanism 10 has a pair of pulleys 11 and an endless conveying belt 12 spanned between the pair of pulleys 11. The plurality of tablets 9 put into the tablet printing device 1 are arranged at equal intervals by a carry-in mechanism 91 including a vibrating feeder, a transport roller, and the like, and are supplied to the outer peripheral surface of the transport belt 12. One of the pair of pulleys 11 is rotated by the power obtained from the conveying motor 13. As a result, the conveyor belt 12 rotates in the direction of the arrow in FIG. 1. At this time, the other of the pair of pulleys 11 rotates in accordance with the rotation of the conveyor belt 12.

FIG. 2 is a partial perspective view of the lozenge conveying mechanism 10. As shown in FIG. 2, a plurality of suction holes 14 are provided in the conveyor belt 12. The plurality of suction holes 14 are arranged at equal intervals in the conveying direction and the width direction. Furthermore, as shown in FIG. 1, the lozenge conveying mechanism 10 has a suction mechanism 15 that sucks gas from the space inside the conveying belt 12. When the suction mechanism 15 is operated, the space inside the conveyor belt 12 becomes a larger air pressure and a lower negative pressure. The plurality of tablets 9 are adsorbed and held by the adsorption holes 14 due to the negative pressure.

In this way, the tablet conveying mechanism 10 conveys the plurality of tablets 9 by the rotation of the conveying belt 12 while holding the plurality of tablets 9 in the plurality of suction holes 14 at regular intervals. Below the four recording heads 21 described later, a plurality of tablets 9 are conveyed in the horizontal direction.

Furthermore, as shown in FIG. 1, the lozenge conveying mechanism 10 has a blowing mechanism 16 inside the conveying belt 12. When the air blowing mechanism 16 is operated, only the suction hole 14 facing the carrying-out mechanism 92 among the plurality of suction holes 14 of the conveying belt 12 becomes a higher positive pressure with a higher air pressure. As a result, the adsorption of the lozenge 9 in the suction hole 14 is released, and the lozenge 9 is delivered from the conveying belt 12 to the unloading mechanism 92. The carrying-out mechanism 92 carries out the lozenge 9 delivered from the transport belt 12 to the outside of the lozenge printing apparatus 1 via another transport belt, for example.

The printing section 20 is a portion where an image is recorded on the surface of the tablet 9 conveyed by the conveying belt 12 by an inkjet method. As shown in FIG. 1, the printing unit 20 of this 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 conveying belt 12 and are arranged in a row along the conveying direction of the tablet 9. The four recording heads 21 eject ink droplets of different colors (for example, each of cyan, magenta, yellow, and black) onto the surface of the tablet 9. Then, a multi-color image is recorded on the surface of the tablet 9 by superimposing the monochromatic images formed by the respective colors. In addition, with regard to the ink ejected from each recording head 21, edible ink manufactured from a raw material approved by the Japanese Pharmacopoeia, the Food Sanitation Law, and the like is used.

FIG. 3 is a bottom view of a recording head 21. As shown in FIG. In FIG. 3, the conveying belt 12 and the plurality of tablets 9 held by the conveying belt 12 are shown by two-dot chain lines. As shown in an enlarged view in FIG. 3, a plurality of ink nozzles 211 capable of ejecting ink droplets are provided on the ejection surface 210 as the lower surface of the recording head 21. In this embodiment, on the lower surface of the recording head 21, a plurality of ink nozzles 211 are arranged two-dimensionally in the conveying direction and the width direction. The ink nozzles 211 are arranged in a shifted position in the width direction. In this way, if the plurality of ink nozzles 211 are arranged two-dimensionally, the positions of the ink nozzles in the width direction can be close to each other. However, the plurality of ink nozzles 211 may be arranged in a row along the width direction.

Regarding the method of ejecting ink droplets from the ink nozzle 211, for example, a so-called piezoelectric method can be used, that is, a piezoelectric element is deformed by applying a voltage to the ink nozzle 211 to pressurize the ink in the ink nozzle 211 to eject it. However, the ink droplet ejection method may also be a so-called thermal type, that is, the ink in the ink nozzle 211 is heated and expanded by energizing a heater, thereby performing ejection.

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 at a position on the downstream side of the printing section 20 in the conveying direction around the conveying belt 12. For the drying mechanism 30, for example, a hot air supply mechanism that blows heated gas (hot air) to the tablets 9 conveyed by the conveying belt 12 can be used. The ink adhering to the surface of the tablet 9 is dried by hot air and fixed to the surface of the tablet 9.

The control unit 40 is a component for controlling the operation of each unit in the tablet printing apparatus 1. The control unit 40 includes a computer having a processor such as a central processing unit (CPU), a memory such as a random access memory (Random Access Memory, RAM), and a storage unit such as a hard disk drive. A computer program for executing printing processing is installed in the storage unit of the control unit. The control unit 40 is communicably connected to the conveying motor 13, the suction mechanism 15, the air blowing mechanism 16, the four recording heads 21, the drying mechanism 30, the carry-in mechanism 91, and the carry-out mechanism 92, respectively. In addition, the control unit 40 may be communicably connected to the vertical movement mechanism 62 and the horizontal movement mechanism 64 described later. The control unit 40 temporarily reads the computer program or data stored in the storage unit to the memory, and the processor performs arithmetic processing based on the computer program, thereby controlling the operation of each unit through the cooperation of hardware and software. In this way, the printing process on the plurality of tablets 9 is performed.

＜2. Details about the printing department＞

FIG. 4 is a side view of the printing unit 20 viewed from the position of the hollow arrow V in FIG. 1. As shown in FIG. 4, the internal space of the tablet printing device 1 is divided into a printing area A1 and a maintenance area A2. The printing area A1 is an area where the tablet 9 is printed while the tablet 9 is transported by the tablet transport mechanism 10. 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, or the ink supply unit 50 described later is replaced. Between the printing area A1 and the maintenance area A2, a partition wall 95 that separates the two areas is provided. The partition wall 95 is parallel to the conveyance direction of the tablet 9 and expands perpendicularly to the horizontal plane.

As described above, the printing section 20 has four recording heads 21. Furthermore, as shown in FIG. 4, the printing section 20 has an ink supply unit (ink supply section) 50 for each recording head 21. In addition, the recording head 21 itself is also included in the ink supply unit 50. In addition, the printing unit 20 has 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 the ink supply unit>

The ink supply unit 50 supplies ink to the printing section 20. As also described above, the ink supply unit 50 is provided for each recording head 21. In addition to the recording head 21, the ink supply unit 50 has an ink pack holding portion 51, a supporting member 53, and an ink pipe 54.

The ink pack holding portion 51 is a holder that can hold the ink pack 110, which is formed by sealing the ink supplied to the recording head 21 in a soft packaging material. The ink pack holding portion 51 can be connected to the recording head 21 via an ink pipe 54 described later. In detail, the ink pack holding portion 51 is configured by overlapping the first side surface portion 512 and the second side surface portion 513 in the conveying direction and coupling them with fastening members such as screws.

The first side surface portion 512 has a rectangular plate shape that extends perpendicularly to the conveying direction. The first side surface portion 512 is arranged in a posture in which the long side of the rectangle is inclined with respect to the horizontal direction. The inclination angle of the long side of the rectangle of the first side surface portion 512 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 still more preferably 10°.

The second side surface portion 513 is a member that can overlap the first side surface portion 512 in the conveying direction. The outer shape of the second side surface portion 513 is substantially the same as the outer shape of the first side surface portion 512. That is, the outer shape of the second side surface portion 513 is rectangular. However, the second side surface portion 513 has a recessed portion 513a that is recessed in a direction away from the first side surface portion 512 in a region other than the edge portion. In addition, strictly speaking, the second side surface portion 513 has a discharge port 514 described later in the outer edge portion. The recessed portion 513a follows the shape of the ink pack 110 described later. On the other hand, the first side surface portion 512 has a lid shape that can cover the recess portion 513a.

The surface of the first side surface portion 512 facing the second side surface portion 513 is one of the “pair of side surfaces” in this embodiment. In addition, the surface of the second side surface portion 513 facing the first side surface portion 512 is the other of the "pair of side surfaces" in this embodiment.

The second side surface portion 513 has a placement bottom surface 513d. Specifically, the surface (bottom surface) on the lower side of the concave portion 513a of the second side surface portion 513 is the placement bottom surface 513d. The placement bottom surface 513d is a plate-shaped portion that receives the ink pack 110 housed in the ink pack holding portion 51 from below. The placement bottom surface 513d is in the shape of an inclined plane that gradually descends vertically downward as it approaches a discharge port 514 described later. The inclination angle of the placement bottom surface 513d 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 still more preferably 10°. The placement bottom surface 513d has a thin shape in the conveying direction.

In the state where the ink pack 110 is housed in the recess 513a, the second side face 513 is overlapped with the first side face 512 in the conveying direction and coupled with each other by a fastening member such as a screw, so that the ink pack 110 can be held in the ink pack In the holding portion 51.

The discharge port 514 is a cylindrical passage that connects the side surface of one side (the side close to the recording head 21) of the recess 513 a in the width direction to the outside of the ink pack holding portion 51. The discharge port 514 of this embodiment extends in a direction inclined with respect to the horizontal direction. One end (base end) of the discharge port 514 is connected to the side surface of one side in the width direction of the recess 513a. The other end portion (front end portion) of the discharge port 514 faces vertically downward as it moves away from the concave portion 513a. That is, the discharge port 514 extends downward obliquely with respect to the horizontal plane.

The discharge port 514 has a shape that follows the bag opening 110a of the ink pack 110 described later. In the discharge port 514, the bag port 110a of the ink pack 110 can be accommodated. The inclination angle of the direction in which the discharge port 514 extends 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 still more preferably 10°. The discharge port 514 is arranged in the vicinity of the placement bottom surface 513d.

The ink pipe 54 has a shape in which a cylindrical pipe is bent in multiple places. One end of the ink pipe 54 is connected to the recording head 21. The other end of the ink pipe 54 is connected to the front end of the discharge port 514. More specifically, the ink pipe 54 has a first pipe 541, a joint portion 542, and a second pipe 543.

The first pipe 541 is a continuous cylindrical pipe that is vertically bent at two places and extends in the width direction as a whole. One end of the first pipe 541 is connected to the recording head 21. The other end of the first pipe 541 is connected to one end of the joint portion 542. The joint portion 542 changes the extending direction of the ink pipe 54. One end of the joint portion 542 is connected to the other end of the first pipe 541. The other end of the joint portion 542 is connected to one end of the second pipe 543.

The second pipe 543 is a continuous cylindrical pipe which is bent vertically at one place and extends in an L shape as a whole. The long-side end (one end) of the second pipe 543 is connected to the other end of the joint portion 542. The short-side front end (the other end) of the second pipe 543 is connected to the front end of the discharge port 514. When viewed in the conveying direction, the discharge port 514 extends in line with the short side of the second pipe 543. Here, the discharge port 514 is located on the upper side in the vertical direction than the short side of the second pipe 543.

The junction of the long side and the short side of the second pipe 543 forms the "bending portion 543a" of the present embodiment. The bent portion 543a is a portion where the internal flow path of the second pipe 543 changes direction. When viewed in the conveying direction, the bent portion 543a is located on the vertically lower side of the discharge port 514.

The ink pipe 54 including the first pipe 541, the joint portion 542, and the second pipe 543 can supply the ink held in the ink pack 110 of the ink pack holding portion 51 to the recording head 21.

The support member 53 has a plate shape perpendicular to the conveying direction, and has a shape long in the width direction. At one end in the width direction of the supporting member 53, the recording head 21 is supported. At the other end in the width direction of the support member 53, the ink pack holding portion 51 is supported. In detail, the difference between the vertical position of the ejection surface 210 of the recording head 21 and the vertical position of the ink enclosed in the ink pack 110 becomes a predetermined allowable range. The ink pack holding portion 51 is positioned and fixed to the supporting member 53. In other words, when the ink pack 110 is attached to the ink pack holding portion 51, the difference between the position of the liquid surface in the ink pack 110 and the liquid surface position of the ink in the ejection surface 210 can be held in each ink nozzle 211. With an appropriate level of meniscus, the relative position of the recording head 21 and the ink pack holding portion 51 in the vertical direction is determined by the supporting member 53.

The recording head 21, the ink pack holding portion 51, the supporting member 53, and the ink pipe 54 are unitized as the ink supply unit 50. That is, the ink supply unit 50 can be integrally attached and detached with respect to other structures of the tablet printing apparatus 1. Specifically, the ink supply unit 50 including the recording head 21, the ink pack holding portion 51, the support member 53, and the ink pipe 54 is detached by sliding movement in the width direction. In the present embodiment, such an ink supply unit 50 is prepared in advance for each type of ink. Thus, by attaching and detaching and replacing the ink supply unit 50, it is possible to print using a plurality of inks, respectively.

＜2-2. About the ink pack＞

The ink pack 110 is an ink supply source held in the ink pack holding portion 51. FIG. 5 is a side view showing the structure of the ink pack 110. As shown in FIG.

The ink pack 110 is formed by encapsulating degassed ink in a soft packaging material. The outer shape of the ink pack 110 when viewed in the conveying direction is substantially rectangular. The ink pack 110 has a flat shape that is thin in the conveying direction. The surface and the back of the ink pack 110 can be easily deformed in the approaching and away directions. When viewed in the posture when the ink pack 110 is attached to the ink pack holding portion 51, a bag opening 110a for pouring (discharging) the ink inside is provided at the end of the ink pack 110 on the vertically lower side. When viewed from the posture when the ink pack 110 is attached to the ink pack holding portion 51, the vertically lower side 110b of the ink pack 110 has an inclined shape that gradually drops vertically downward as it approaches the pack opening 110a. The inclination rate of the side 110b of the ink pack 110 with respect to the horizontal direction coincides with the inclination rate of the placement bottom surface 513d with respect to the horizontal direction.

<2-3. About the moving mechanism of the ink supply unit>

Return to Figure 4. The ink supply unit moving mechanism 60 is a mechanism that moves the ink supply unit 50 between the printing 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 from the printing area A1 to the maintenance area A2 in an on-carriage manner. The ink supply unit moving mechanism 60 of this embodiment has an arm 61, an up-and-down moving mechanism 62, a moving platform 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 front end of the arm 61.

The up-and-down movement mechanism 62 moves the arm 61 up and down in accordance with an instruction from the control unit 40. When the vertical movement mechanism 62 is operated, the ink supply unit 50 including the arm 61 and the recording head 21 moves vertically as an arrow D1 in FIG. 4. Thus, 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 addition, in the maintenance area A2, by using the vertical movement mechanism 62 to lower the recording head 21, the cleaning unit 71 can also act on the ejection surface 210 of the recording head 21. Thereby, the ejection surface 210 can be cleaned and maintained.

The up-and-down moving mechanism 62 is supported by the moving platform 63. The horizontal moving mechanism 64 moves the moving platform 63 in the width direction. As a result, the moving platform 63, the vertical moving mechanism 62, the arm 61, and the ink supply unit 50 are integrated and move in the width direction as indicated by the arrow D2 in FIG. 4. Regarding the horizontal movement mechanism 64 and the vertical movement mechanism 62, for example, a mechanism that converts the rotational movement of a motor into a linear movement via a ball screw can be used. However, the horizontal movement mechanism 64 and the vertical movement mechanism 62 may also be realized by other mechanisms such as a linear motor or an air cylinder.

In the pastille printing apparatus 1 having the above-mentioned configuration, the ink supply unit 50 is mounted on the printing section 20 by mounting the recording head 21 and the supporting member 53 on the arm 61. As a result, the ink pack 110 can be attached to the ink pack holding portion 51 in a state where the recording head 21 is moved in the width direction from a position above the conveying belt 12 to the farthest position by the horizontal movement mechanism 64. As a result, it is possible to sufficiently ensure a space for the operator to perform installation work at a position away from the conveyor belt 12 in the width direction.

The installation of the ink pack 110 to the ink pack holding portion 51 is performed as follows. That is, first, the operator removes the first side surface portion 512 from the ink pack holding portion 51 by removing the fastening member. Next, the operator inserts the bag opening 110a of the ink pack 110 into the discharge port 514 to be in a connected state, and fits the ink pack 110 into the recess 513a of the second side part 513. At this time, the vertically lower side 110b of the ink pack 110 is received from below by the placement bottom surface 513d. In this state, the operator tightens the fastening member again, thereby mounting the second side surface portion 513 with respect to the first side surface portion 512. As a result, the ink pack 110 is in a state of being sandwiched from both sides by a pair of side surfaces.

Then, the water pressure from the ink pack 110 supplies ink to each ink nozzle 211 via the ink pipe 54. At this time, in the ink supply unit 50, the relative relationship between the position of the ejection surface 210 and the position of the ink pack holding portion 51 in the vertical direction is appropriately set. Specifically, the position of the ejection surface 210 in the vertical direction is set to be higher than the position of the center of gravity of the ink in the ink pack 110 held by the ink pack holding portion 51 by a predetermined amount. Therefore, it is impossible for ink droplets to drop from the ejection surface 210. That is, in each ink nozzle 211, an appropriate meniscus is maintained. In addition, the position of the ejection surface 210 and the position of the ink pack holding portion 51 in the vertical direction are appropriately set in relation to each other, so there is little possibility that the ink will flow back from the recording head 21 to the ink pack 110.

According to the above-mentioned configuration, in the tablet printing apparatus 1 of the present embodiment, the difference between the vertical position of the ink in the ink pack 110 and the vertical position of the ejection surface 210 is maintained within the allowable range. Therefore, even if a pump or the like is not installed in the middle of the ink pipe 54, ink can be supplied to the ink nozzle 211 by using the difference in water head.

During printing, the recording head 21 is placed at a position above the conveyor belt 12 by the horizontal movement mechanism 64, and a voltage is applied to the piezoelectric element in accordance with an instruction from the control unit 40, thereby causing the ink droplets to move from The ink nozzle 211 ejects.

Here, if ink droplets in the ink nozzle 211 are consumed due to printing, the thickness of the ink pack 110 in the horizontal direction gradually becomes thinner. In detail, the upper part of the ink pack 110 is in a state where the surface and the back of the soft packaging material are gradually approaching. Therefore, as the consumption of ink increases, the thickness of the ink pack 110 in the horizontal direction becomes thinner. Therefore, even if the ink is consumed, the liquid level position of the ink in the ink pack 110 does not change significantly. That is, assuming that a normal ink tank is used as the ink supply source, the level of the ink in the ink tank decreases linearly as the ink is consumed. However, the ink pack 110 is used as the ink supply source as in this embodiment. In this case, the descending speed of the ink level position becomes slow. Therefore, even if the printing process is performed, the head difference between the liquid level of the ink in the ink pack 110 and the ejection surface 210 can be kept within the allowable range for a long period of time. As a result, printing can be performed efficiently without interrupting the printing process frequently to replenish ink.

In particular, in this embodiment, the side 110b on the vertically downward side of the ink pack 110 attached to the ink pack holding portion 51 has a shape that descends to the vertically downward side as it approaches the bag opening 110a. In detail, the ink pack 110 has a tapered shape toward the lower end, and the amount of the accumulated ink decreases as it goes toward the lower end. Therefore, compared with the case of using an ink pack whose lower end is not a tapered shape, the liquid surface position of the ink becomes higher when the remaining amount of ink is the same. Therefore, it is possible to further extend the time for maintaining the liquid level position of the ink at a height within the allowable range of the head difference. Therefore, even if the printing process is performed, the liquid level of the ink in the ink pack 110 and the water head difference of the ejection surface 210 can be appropriately maintained for a long period of time. Furthermore, the shape of the side 110b and the placement bottom surface 513d can promote the movement of the ink in the ink pack 110 to the discharge port 514 side. In Fig. 5, the direction of ink movement is indicated by a hollow arrow. Therefore, it is difficult to produce a situation in which the remaining ink in the ink pack 110 is reduced, and the remaining ink is broken in the vertical direction.

If the remaining amount of ink in the ink pack 110 is reduced, the first side surface portion 512 of the ink pack holding portion 51 can be detached and replaced with a new ink pack 110 by the same method as described above.

In addition, conventionally, when the remaining amount of ink in the ink pack is reduced, air bubbles may be mixed into the ink piping when the ink pack is attached or detached. If large air bubbles are mixed into the ink piping, it is difficult to degas with a deaeration filter or the like, and the air bubbles may cause printing defects such as missing printing. In this regard, in the present embodiment, the inclination rate of the discharge port 514 or the positional relationship between the discharge port 514 and the second pipe 543 are adjusted to prevent air bubbles from being mixed into the ink pipe 54.

Specifically, the short side of the discharge port 514 and the second pipe 543 are connected in an inclined linear shape inclined with respect to the horizontal direction, and the discharge port 514 is arranged at a higher position. Therefore, air bubbles mixed in during the loading and unloading of the ink pack 110 flow to the proximal end side of the discharge port 514 instead of the second pipe 543 side. That is, the position of the discharge port 514 in the vertical direction is higher than the position of the bent portion 543a in the vertical direction, which is the lowest point of the ink pipe 54 in the vertical direction. Therefore, air bubbles having a lighter specific gravity than the ink naturally flow to the discharge port 514.

＜3. Summary＞

As described above, the ink supply unit (ink supply unit) 50 included in the pastille printing device (printing device) 1 of the present embodiment includes the recording head 21, the ink pack holding unit 51, and the ink pipe 54. The ink pack holding portion 51 includes a cylindrical discharge port 514 that discharges the ink in the ink pack 110 to the recording head 21. The discharge port 514 is arranged obliquely with respect to the horizontal direction. The front end of the discharge port 514 faces vertically downward as it moves away from the ink pack 110. As a result, air bubbles mixed in the vicinity of the discharge port 514 when the ink pack 110 is attached or detached easily escape into the ink pack 110 through the discharge port 514. Therefore, it is possible to suppress the occurrence of printing defects such as print omissions caused by air bubbles.

Furthermore, in the ink supply unit 50 of the present embodiment, the other end of the ink pipe 54 (the second pipe 543) and the front end of the discharge port 514 are connected in a straight line. As a result, air bubbles mixed in the vicinity of the discharge port 514 during attachment and detachment of the ink pack 110 are more likely to escape into the ink pack 110 through the discharge port 514 than the inside of the ink pipe 54.

In addition, in the ink supply unit 50 of the present embodiment, the bent portion 543 a that changes the direction of the internal flow path, which is a midway portion of the ink pipe 54, is located vertically below the discharge port 514. As a result, air bubbles mixed in the vicinity of the discharge port 514 when the ink pack 110 is attached and detached more easily escape into the ink pack 110.

In addition, in the ink supply unit 50 of the present embodiment, the bent portion 543 a is located on the most vertically downward side of the ink pipe 54. As a result, air bubbles mixed in the vicinity of the discharge port 514 during attachment and detachment of the ink pack 110 are more likely to escape to the inside of the ink pack 110.

Furthermore, in the ink supply unit 50 of the present embodiment, the discharge port 514 is located on the vertical lower side of the ejection surface 210 of the recording head 21. Therefore, for example, the vertical position of the discharge surface 210 is set higher than the vertical position of the ink enclosed in the ink pack 110 by a predetermined amount, so that the discharge port 514 and the discharge surface 210 are set in the vertical direction. The positional relationship of the ink nozzles can appropriately maintain the meniscus in the ink nozzle.

In addition, the ink pack holding portion 51 of the present embodiment has a pair of side surfaces extending vertically upward from the placement bottom surface 513d. The ink pack 110 is clamped from both sides by the pair of side surfaces. Thereby, the ink pack 110 is received from below by the mounting bottom surface 513d, and the ink pack 110 is clamped from both sides by a pair of side surfaces. In this way, it is easy to gradually reduce the thickness of the ink pack 110 in the horizontal direction as the ink is consumed. Thus, even if the ink is consumed, the position of the ink level in the ink pack 110 does not change much.

In addition, in the ink supply unit 50 of the present embodiment, the placement bottom surface 513 d is in the shape of an inclined plane that gradually descends vertically downward as it approaches the discharge port 514. As a result, the ink in the ink pack 110 can be promoted to move to the discharge port 514 side, and it is not easy to cause the following situation: when the remaining amount of ink in the ink pack 110 becomes small, the remaining ink is divided in the vertical direction. Wait.

Furthermore, as shown in FIG. 5, the ink pack holding part 51 of this embodiment has a shape longer in a horizontal direction than a vertical direction. As a result, it is possible to mount a large capacity in an area where the difference between the vertical position of the ejection surface 210 and the vertical position of the ink enclosed in the ink pack 110 is within a predetermined allowable range (ideal head difference) Of ink. As a result, the interruption frequency of the printing process for replenishing ink etc. can be suppressed to be less, and printing can be performed continuously.

Furthermore, the ink supply unit 50 of this embodiment further includes a support member 53 that supports the recording head 21 at one end and supports the ink pack holding portion 51 at the other end. As a result, it is easy to arrange the ink in the ink pack 110 in a pre-positioned state so that the difference between the vertical position of the ink in the ink pack 110 and the vertical position of the ejection surface 210 is maintained within the allowable range.

Furthermore, in the ink supply unit 50 of the present embodiment, the unit including the recording head 21, the ink pack holding portion 51, the ink pipe 54 and the supporting member 53 can be integrally attached to and detached from the other structure of the tablet printing apparatus 1. Thereby, the relative relationship of the position of the ejection surface 210, the position of the ink pack holding portion 51, and the position of the ink pipe 54 in the vertical direction can be unitized and operated by the ink supply unit 50 in a state where it is appropriately set. Therefore, for example, by pre-preparing such units for each of different types of inks, it is possible to print with multiple types of inks by attaching and detaching the replacement unit.

＜4. Regarding modified examples＞

As mentioned above, although the suitable embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it does not deviate from the summary, the said embodiment can be variously changed.

In the above embodiment, the ink pack 110 has a rectangular shape when viewed in the conveying direction, but it is not limited to this. For example, the shape of the ink pack may be trapezoidal or triangular when viewed in the conveying direction.

In the above-described embodiment, it is assumed that the ink pack 110 of a predetermined shape (capacity) can be attached to the ink pack holding portion 51, but it is not limited to this. Alternatively, ink packs of different capacities may be selectively installed in the ink pack holding portion 51.

In the above-described embodiment, it is assumed that only the second side surface portion 513 of the ink pack holding portion 51 is provided with the concave portion 513a accommodating the ink pack 110, but it is not limited to this. Alternatively, the ink pack holding portion 51 may be provided with recesses for accommodating the ink pack 110 at both the first side surface portion 512 and the second side surface portion 513.

In addition, the respective elements appearing in the above-mentioned embodiments or modified examples may be appropriately combined within a range that does not cause any contradiction.

1: Tablet printing device (printing device) 9: lozenge 10: Lozenge conveying mechanism 11: pulley 12: Conveyor belt 13: Conveying motor 14: adsorption hole 15: Suction mechanism 16: blowing mechanism 20: Printing Department 21: record head 30: Drying mechanism 40: Control Department 50: Ink supply unit (ink supply part) 51: Ink pack holding part 53: Supporting member 54: Ink piping 60: Ink supply unit moving mechanism 61: Arm 62: Up and down moving mechanism 63: mobile platform 64: Horizontal movement mechanism 71: Cleaning unit 91: Move into the organization 92: Move out of the organization 95: Separation Wall 110: ink bag 110a: bag mouth 110b: side 210: Gushing Surface 211: Ink nozzle 512: First side 513: second side 513a: recess 513d: Place the bottom surface 514: Exhaust outlet 541: first piping 542: Joint 543: second piping 543a: Bending part A1: Printing area A2: Maintenance area D1, D2: Arrow V: hollow arrow

Fig. 1 is a diagram showing a schematic configuration of a tablet printing device. Fig. 2 is a partial perspective view of the lozenge conveying mechanism. Figure 3 is a bottom view of the recording head. Fig. 4 is a side view of the ink supply unit. Figure 5 is a side view of the ink pack.

9: lozenge

10: Lozenge conveying mechanism

12: Conveyor belt

20: Printing Department

21: record head

50: Ink supply unit (ink supply part)

51: Ink pack holding part

53: Supporting member

54: Ink piping

60: Ink supply unit moving mechanism

61: Arm

62: Up and down moving mechanism

63: mobile platform

64: Horizontal movement mechanism

71: Cleaning unit

95: Separation Wall

210: Gushing Surface

512: First side

513: second side

513a: recess

513d: Place the bottom surface

514: Exhaust outlet

541: first piping

542: Joint

543: second piping

543a: Bending part

A1: Printing area

A2: Maintenance area

D1, D2: Arrow

Claims (13)

An ink supply unit is provided by a printing device that performs printing on the surface of a recording medium by an inkjet method, and includes: a recording head having an ejection surface arranged with a plurality of ink nozzles that eject ink droplets; and an ink pack A holding portion capable of holding an ink pack formed by enclosing the ink supplied to the recording head in a soft packaging material, and including a cylindrical discharge port, which discharges the ink in the ink pack to the recording head; And the ink piping is cylindrical, one end is connected to the recording head, and the other end is connected to the discharge port, wherein, in a posture where the ink pack is mounted on the ink pack holding portion, the discharge port Connected to the package opening provided at the end of the ink pack on the vertically lower side, the discharge port is arranged obliquely with respect to the horizontal direction, and the front end of the discharge port faces the lead as it moves away from the ink pack Hang down. The ink supply unit according to claim 1, wherein the other end of the ink pipe is connected to the front end of the discharge port in a straight line. The ink supply unit according to claim 1 or 2, wherein the bent portion that changes the direction of the internal flow path is located at a vertical lower side than the discharge port as a halfway portion of the ink pipe. The ink supply unit according to claim 3, wherein: The bent portion is located on the most vertically lower side of the ink pipe. The ink supply unit according to claim 3, wherein the discharge port is located on a vertically lower side than the ejection surface of the recording head. The ink supply unit according to claim 3, wherein the ink pack holding part has a placement bottom surface that receives the ink pack from below. The ink supply unit according to claim 6, wherein the ink pack holding portion has a pair of side surfaces extending vertically upward from the placement bottom surface, and the ink pack is sandwiched from both sides by the pair of side surfaces hold. The ink supply unit according to claim 6, wherein the placement bottom surface has an inclined plane shape that gradually drops vertically downward as it approaches the discharge port. The ink supply part according to claim 5, wherein the ink pack holding part has a shape longer in the horizontal direction than in the vertical direction. The ink supply part according to claim 1 or 2, further comprising: a support member that supports the recording head at one end and supports the ink pack holding part at the other end. The ink supply unit according to claim 10, wherein a unit including the recording head, the ink pack holding unit, the ink piping, and the support member can be integrated with another structure of the printing device Pack Unload. A printing device includes the ink supply unit described in claim 1 or 2. A lozenge printing device, comprising the ink supply unit described in claim 1 or 2, and printing on the surface of the lozenge as the recording medium in an inkjet manner.

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