JP2021041678A - Ink supply part, printer, and tablet printer - Google Patents

Abstract

To inhibit occurrence of printing failure, such as missing a part in printing, caused by air bubbles.SOLUTION: An ink supply unit (an ink supply part) 50 includes: a recording head 21; an ink pouch holding part 51; and an ink pipe 54. The recording head 21 has a discharge surface 210 on which ink nozzles for discharging ink droplets are aligned. The ink pouch holding part 51 can hold an ink pouch in which an ink to be supplied to the recording head 21 is enclosed in a soft packaging material. The ink pouch holding part 51 includes a cylindrical discharge port 514 which discharges the ink in the ink pouch to the recording head 21. The ink pipe 54 has a cylindrical shape, is connected to the recording head 21 at one end, and is connected to the discharge port 514 at the other end. The discharge port 514 is disposed at an angle to a horizontal direction. A tip of the discharge port 514 is lowered vertically in a direction away from the ink pouch.SELECTED DRAWING: Figure 4

Description

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

Conventionally, an ink supply unit provided in a printing apparatus that prints on the surface of a recording medium by an inkjet method is known. This type of ink supply unit is disclosed in, for example, Patent Document 1.

The inkjet printer described in Patent Document 1 includes an ink supply needle (3) for supplying ink to the recording head (2) side and an ink container (1) for storing ink, and includes an ink supply needle (3). Is pierced into the ink container (1) to supply ink from the ink container (1) to the recording head (2) side. The ink container (1) is made of a flexible 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. There is.

JP-A-2002-347259

However, in the inkjet printer described in Patent Document 1, it is considered that air bubbles may be mixed in the ink supply needle when the ink container is attached or detached due to a decrease in the remaining amount of ink in the ink container. Be done. If air bubbles are mixed in the ink supply needle, it is difficult to degas by a degassing filter or the like, and there is a possibility that printing defects such as printing omission may occur due to these air bubbles.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the occurrence of printing defects such as print omissions caused by air bubbles.

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

From the first aspect of the present application, there is provided an ink supply unit provided in a printing apparatus that prints 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 an ink pipe. The recording head has an ejection surface in which a plurality of ink nozzles for ejecting ink droplets are arranged. The ink pouch holding portion can hold an ink pouch in which ink supplied to the recording head is sealed in a soft packaging material. The ink pouch holding portion includes a tubular discharge port for discharging the ink in the ink pouch toward the recording head. The ink pipe has a cylindrical shape, one end of which is connected to the recording head and the other end of which is connected to the discharge port. The discharge port is arranged so as to be inclined with respect to the horizontal direction. The tip of the discharge port moves vertically downward as the distance from the ink pouch increases.

In the second aspect of the present application, in the ink supply unit according to the first aspect, the other end of the ink pipe is connected in a straight line with the tip portion of the discharge port.

From the third aspect of the present application, in the ink supply unit according to the first aspect or the second aspect, the bent portion, which is the middle portion of the ink pipe and the direction of the internal flow path changes, is larger than that of the discharge port. It is located vertically below.

From the fourth aspect of the present application, in the ink supply unit according to the third aspect, the bent portion is located on the most vertically downward side of the ink pipe.

From the fifth aspect of the present application, in the ink supply unit according to the third or fourth aspect, the discharge port is located vertically below the discharge surface of the recording head.

From the sixth aspect of the present application, in the ink supply unit according to any one of the third to fifth aspects, the ink pouch holding unit has a mounting bottom surface that receives the ink pouch from below.

From the seventh aspect of the present application, in the ink supply unit according to the sixth aspect, the ink pouch holding portion has a pair of side surfaces extending vertically upward from the above-described bottom surface. The ink pouch is sandwiched from both sides by the pair of side surfaces.

From the eighth aspect of the present application, in the ink supply unit according to the sixth aspect or the seventh aspect, the above-described bottom surface is an inclined flat surface that gradually lowers vertically downward as it approaches the discharge port.

From the ninth aspect of the present application, in the ink supply unit according to the fifth aspect, the ink pouch holding portion has a shape longer in the horizontal direction than in the vertical direction.

From the tenth aspect of the present application, in the ink supply unit according to any one of the first to ninth aspects, the recording head is supported at one end and the ink pouch is held at the other end. A support member is further provided to support the portion.

From the eleventh aspect of the present application, in the ink supply unit according to the tenth aspect, the unit including the recording head, the ink pouch holding unit, the ink pipe, and the support member is the other of the printing apparatus. It is integrally removable with respect to the configuration of.

A twelfth aspect of the present application provides a printing apparatus including an ink supply unit according to any one of the first aspect to the eleventh aspect.

From the thirteenth aspect of the present application, a tablet printing apparatus including an ink supply unit according to any one of the first to eleventh viewpoints and printing on the surface of a tablet as a recording medium by an inkjet method. Provided.

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

In particular, according to the first aspect of the present application, air bubbles mixed in the vicinity of the discharge port when the ink pouch is attached / detached easily escape to the inside of the ink pouch through the discharge port.

In particular, according to the second aspect of the present application, air bubbles mixed in the vicinity of the discharge port when the ink pouch is attached / detached are more likely to escape to the inside of the ink pouch through the discharge port than inside the ink pipe.

In particular, according to the third aspect of the present application, air bubbles mixed in the vicinity of the discharge port when the ink pouch is attached / detached are more likely to escape to the inside of the ink pouch.

In particular, according to the fourth aspect of the present application, air bubbles mixed in the vicinity of the discharge port when the ink pouch is attached / detached are more likely to escape to the inside of the ink pouch.

In particular, according to the fifth aspect 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 level of the ink encapsulated in the ink pouch in the vertical direction is within a predetermined allowable range (ideal). By setting the positional relationship between the discharge port and the discharge surface in the vertical direction so as to have a water head difference), it is possible to properly hold the meniscus in the ink nozzle.

In particular, according to the seventh aspect of the present application, by receiving the ink pouch from below on the mounting bottom surface and sandwiching it from both sides on a pair of side surfaces, the horizontal thickness of the ink pouch is gradually increased as the ink is consumed. It becomes easy to make it thin. As a result, even if the ink is consumed, the liquid level position of the ink in the ink pouch does not fluctuate so much.

In particular, according to the eighth aspect of the present application, the movement of the ink in the ink pouch toward the ejection port side can be promoted, so that when the ink in the ink pouch is low, the remaining ink is divided in the vertical direction. It is less likely that the situation will occur.

In particular, according to the ninth aspect of the present application, the difference between the vertical position of the ejection surface and the vertical liquid level position of the ink encapsulated in the ink pouch is within a predetermined allowable range (ideal head). A large amount of ink can be mounted in the area where the difference is (difference). As a result, the frequency of interruption of the printing process for replenishing ink or the like can be suppressed, and continuous printing can be performed. It also reduces the possibility of air bubbles entering when the ink pouch is attached and detached.

In particular, according to the tenth aspect of the present application, the difference between the vertical position of the ink in the ink pouch and the vertical position of the ejection surface is kept within an allowable range in advance. It becomes easy to arrange in the positioned state.

In particular, according to the eleventh viewpoint of the present application, the ink supply unit in a state in which the relative relationship between the position of the ejection surface, the position of the ink pouch holding portion, and the position of the ink pipe in the vertical direction is appropriately set is provided. , It becomes possible to handle as a unit. Therefore, for example, by preparing such a unit for each of different types of ink in advance, it is possible to print by using a plurality of types of ink properly by attaching and detaching the unit and replacing the unit.

It is a figure which showed the schematic structure of the tablet printing apparatus. It is a partial perspective view of a tablet transport mechanism. It is a bottom view of the head. It is a side view of the 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, the direction in which a plurality of tablets are transported is referred to as a "transport direction", and the direction perpendicular to 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 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 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 which are pharmaceutical products. As shown in FIG. 1, the tablet printing device 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 for transporting 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 spanned between the pair of pulleys 11. The plurality of tablets 9 charged into the tablet printing device 1 are aligned at equal intervals by a carry-in mechanism 91 composed of a vibration feeder, a transport drum, 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 transport motor 13. As a result, 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 as the transport belt 12 rotates.

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 the space inside the transport belt 12. When the suction mechanism 15 is operated, the space inside the transport belt 12 becomes a negative pressure lower than the atmospheric pressure. The plurality of tablets 9 are adsorbed and held in the adsorption holes 14 by the negative pressure.

In this way, 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 regular intervals. Below the four recording heads 21, which will be described later, 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, of the plurality of suction holes 14 of the transport belt 12, only the suction holes 14 facing the carry-out mechanism 92 have a positive pressure higher than the atmospheric pressure. As a result, the adsorption of the tablet 9 in the suction hole 14 is released, and the tablet 9 is delivered from the transport belt 12 to the carry-out mechanism 92. The carry-out mechanism 92 carries out the tablet 9 delivered from the transport belt 12 to the outside of the tablet printing device 1 by, for example, another transport belt.

The printing unit 20 is a portion for recording 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 this embodiment has four recording heads 21. Each recording head 21 is included in the ink supply unit 50, which will be described later. The four recording heads 21 are located above the transport belt 12 and are arranged in a row 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 monochromatic images formed by each of these colors. As the ink discharged from each recording head 21, edible ink produced from raw materials approved by the Japanese Pharmacopoeia, the Food Sanitation Law, etc. is used.

FIG. 3 is a bottom view of one recording head 21. In FIG. 3, the transport belt 12 and the plurality of tablets 9 held by the transport belt 12 are shown by an alternate long and short dash line. As shown enlarged in FIG. 3, a plurality of ink nozzles 211 capable of ejecting ink droplets are provided on the ejection surface 210 which is the 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 so as to be displaced in the width direction. By arranging the plurality of ink nozzles 211 two-dimensionally in this way, the positions of the ink nozzles in the width direction can be brought close to each other. However, the plurality of ink nozzles 211 may be arranged in a row along the width direction.

As a method for ejecting ink droplets from the ink nozzle 211, for example, a so-called piezo method is used in which the ink in the ink nozzle 211 is pressurized and ejected by applying a voltage to the piezo element to deform it. However, the ink droplet ejection method may be a so-called thermal system in which the heater is energized to heat and expand the ink in the ink nozzle 211 to eject the ink droplets.

The drying mechanism 30 is a mechanism for drying the ink adhering 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 portion 20 in the transport direction. As the drying mechanism 30, for example, a hot air supply mechanism that blows a heated gas (hot air) toward the tablets 9 transported by the transport belt 12 is used. The ink adhering 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 means for controlling the operation of each unit in the tablet printing apparatus 1. The control unit 40 is composed of 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 includes the above-mentioned transfer motor 13, suction mechanism 15, blow mechanism 16, and four recording heads 21. It is communicably connected to the drying mechanism 30, the carry-in mechanism 91, and the carry-out mechanism 92, respectively. Further, the control unit 40 is also communicably connected to the vertical movement mechanism 62 and the horizontal movement mechanism 64, which will be described later. The control unit 40 temporarily reads the computer program and data stored in the storage unit into the memory, and the processor performs arithmetic processing based on the computer program, thereby collaborating with hardware and software. The operation of each part of is controlled. As a result, the printing process for the plurality of tablets 9 proceeds.

<2. About the details of the printing department ＞
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 for printing on the tablets 9 while transporting the tablets 9 by the tablet transport mechanism 10 described above. The maintenance area A2 is an area for making the recording head 21 stand by before or after printing, cleaning the ejection surface 210 of the recording head 21, and replacing the ink supply unit 50 described later. A partition wall 95 that separates both areas is provided between the print area A1 and the maintenance area A2. 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 (ink supply unit) 50 for each recording head 21. The ink supply unit 50 also includes the recording head 21 itself. Further, 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 unit 20. As 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 includes an ink pouch holding portion 51, a support member 53, and an ink pipe 54.

The ink pouch holding portion 51 is a holder capable of holding the ink pouch 110 in which the ink supplied to the recording head 21 is sealed in a soft packaging material. The ink pouch holding portion 51 can be connected to the recording head 21 via an ink pipe 54 described later. Specifically, the ink pouch holding portion 51 is configured by overlapping the first side surface portion 512 and the second side surface portion 513 in the transport direction and connecting them to each other with a fastening member such as a screw.

The first side surface portion 512 has a rectangular plate shape that extends perpendicularly to the transport 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 even more preferably 10 °.

The second side surface portion 513 is a member capable of being superposed on the first side surface portion 512 in the transport 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 recess 513a recessed in a direction away from the first side surface portion 512 in a region other than the outer edge portion. Strictly speaking, the second side surface portion 513 has a discharge port 514 described later at the outer edge portion. The recess 513a follows the shape of the ink pouch 110, which will be described later. On the other hand, the first side surface portion 512 has a lid shape capable of covering the recess 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" according to the present embodiment. 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" according to the present embodiment.

The second side surface portion 513 has a mounting bottom surface 513d. Specifically, the lower surface (bottom surface) of the recess 513a of the second side surface portion 513 is the mounting bottom surface 513d. The mounting bottom surface 513d is a plate-shaped portion that receives the ink pouch 110 housed in the ink pouch holding portion 51 from the lower side. The mounting bottom surface 513d has an inclined flat surface that gradually lowers vertically downward as it approaches the discharge port 514, which will be described later. The inclination angle of the mounting 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 even more preferably 10 °. The mounting bottom surface 513d has a thin shape in the transport direction.

With the ink pouch 110 housed in the recess 513a, the ink pouch 110 is ink-inked by superimposing the first side surface portion 512 on the second side surface portion 513 in the transport direction and connecting the ink pouch 110 to each other with a fastening member such as a screw. It can be held in the pouch holding portion 51.

The discharge port 514 is a tubular passage that connects the side surface of the recess 513a on one side in the width direction (the side closer to the recording head 21) to the outside of the ink pouch holding portion 51. The discharge port 514 of the present embodiment extends in a direction inclined with respect to the horizontal direction. One end (base end portion) of the discharge port 514 is connected to one side surface of the recess 513a in the width direction. The other end (tip) of the discharge port 514 moves vertically downward as the distance from the recess 513a increases. That is, the discharge port 514 extends diagonally downward with respect to the horizontal plane.

The discharge port 514 has a shape along the pouch port 110a of the ink pouch 110 described later. The pouch port 110a of the ink pouch 110 can be accommodated in the discharge port 514. The inclination angle of the discharge port 514 in the extending direction 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 discharge port 514 is arranged in the vicinity of the mounting bottom surface 513d.

The ink pipe 54 has a shape in which a cylindrical pipe is bent at a plurality of points. 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 tip 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.

In the first pipe 541, a continuous cylindrical pipe is bent vertically at two points 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.

In the second pipe 543, a continuous cylindrical pipe is bent vertically at one point and extends in an L shape as a whole. The tip (one end) on the long side of the second pipe 543 is connected to the other end of the joint portion 542. The tip (the other end) on the short side of the second pipe 543 is connected to the tip of the discharge port 514. The discharge port 514 and the short side of the second pipe 543 extend in a straight line when viewed in the transport direction. Here, the discharge port 514 is located on the upper side in the vertical direction with respect to the short side of the second pipe 543.

The connection portion between the long side and the short side of the second pipe 543 forms the "bent portion 543a" according to 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 transport direction, the bent portion 543a is located vertically below the discharge port 514.

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

The support member 53 has a plate shape perpendicular to the transport direction and a long shape 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 holding portion 51 is supported at the other end of the support member 53 in the width direction. Specifically, the recording head so that the difference between the vertical position of the ejection surface 210 of the recording head 21 and the liquid level position of the ink encapsulated in the ink pouch 110 in the vertical direction is within a predetermined allowable range. The 21 and the ink pouch holding portion 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 portion 51, the head difference between the liquid level position in the ink pouch 110 and the liquid level position of the ink on the ejection surface 210 is. The relative position of the recording head 21 and the ink pouch holding portion 51 in the vertical direction is determined by the support member 53 so that the head difference is such that an appropriate meniscus can be held in each ink nozzle 211. There is.

The recording head 21, the ink pouch holding portion 51, the support member 53, and the ink pipe 54 are unitized as an ink supply unit 50. That is, the ink supply unit 50 is integrally removable from the other configurations of the tablet printing device 1. Specifically, the ink supply unit 50 including the recording head 21, the ink pouch holding portion 51, the support member 53, and the ink pipe 54 is attached / detached by being slid in the width direction. In the present embodiment, such an ink supply unit 50 is prepared in advance for each of different types of ink. As a result, by attaching and detaching the ink supply unit 50 and replacing it, it is possible to print by using a plurality of types of ink properly.

<2-2. About ink pouches>
The ink pouch 110 is an ink supply source held by the ink pouch holding portion 51 described above. FIG. 5 is a side view showing the configuration of the ink pouch 110.

The ink pouch 110 is a soft packaging material in which degassed ink is sealed. The ink pouch 110 has a substantially rectangular outer shape when viewed in the transport direction. The ink pouch 110 has a flat shape that is thin in the transport direction. The ink pouch 110 can be easily deformed in the direction in which the front surface and the back surface are close to each other and separated from each other. When viewed in the posture when the ink pouch 110 is attached to the ink pouch holding portion 51, a pouch port 110a for pouring (discharging) the ink inside is provided at the vertically lower end of the ink pouch 110. There is. When the ink pouch 110 is attached to the ink pouch holding portion 51, the vertically downward side 110b of the ink pouch 110 has an inclined shape that gradually decreases vertically downward as it approaches the pouch opening 110a. The inclination of the side 110b of the ink pouch 110 with respect to the horizontal direction coincides with the inclination of the mounting bottom surface 513d with respect to the horizontal direction.

<2-3. About the movement mechanism of the ink supply unit>
Return to FIG. The ink supply unit moving mechanism 60 is a mechanism for moving 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 an on-carriage type mechanism for moving the recording head 21 from the printing area A1 to the maintenance area A2. The ink supply unit moving mechanism 60 of the present embodiment includes 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. When the vertical movement mechanism 62 is operated, the arm 61 and the ink supply unit 50 including the recording head 21 move up and down as a unit, as shown by the arrow D1 in FIG. Thereby, the position of the discharge surface 210 in the vertical direction can be adjusted according to the thickness of the tablet 9 to be printed. Further, in the maintenance area A2, the cleaning unit 71 can act on the discharge surface 210 of the recording head 21 by lowering the recording head 21 by the vertical movement mechanism 62. As a result, the discharge surface 210 can be cleaned and maintained.

The vertical movement mechanism 62 is supported by the movement stage 63. The horizontal movement mechanism 64 moves the movement 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 are integrally moved in the width direction as shown by the arrow D2 in FIG. As the horizontal movement mechanism 64 and the vertical movement mechanism 62, for example, a mechanism that converts the rotational movement of the motor into a linear movement via a ball screw is used. However, the horizontal movement mechanism 64 and the vertical movement mechanism 62 may be realized by other mechanisms such as a linear motor and an air cylinder.

In the tablet printing apparatus 1 having the above configuration, 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 horizontal movement mechanism 64 makes it possible to attach the ink pouch 110 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. Is. As a result, a space for the operator to perform the mounting work can be sufficiently secured at a position separated from the transport belt 12 in the width direction.

The ink pouch 110 is attached to the ink pouch holding portion 51 as follows. That is, first, the operator removes the first side surface portion 512 from the ink pouch holding portion 51 by removing the fastening member. Then, the operator inserts the ink pouch 110 into the recess 513a of the second side surface portion 513 while inserting the pouch port 110a of the ink pouch 110 into the discharge port 514 to connect the ink pouch 110. At this time, the vertically lower side 110b of the ink pouch 110 is received from below by the mounting bottom surface 513d. In this state, the operator attaches the first side surface portion 512 to the second side surface portion 513 by tightening the fastening member again. As a result, the ink pouch 110 is sandwiched from both sides by a pair of side surfaces.

Then, the water pressure from the ink pouch 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 pouch 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 pouch 110 held by the ink pouch holding portion 51 by a predetermined amount. Therefore, there is no possibility that ink droplets will drip from the ejection surface 210. That is, each ink nozzle 211 holds an appropriate meniscus. Moreover, since the relative relationship between the position of the ejection surface 210 and the position of the ink pouch holding portion 51 in the vertical direction is properly set, there is a risk that ink will flow back from the recording head 21 to the ink pouch 110. There are few.

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, ink can be supplied to the ink nozzle 211 by utilizing the plumb bob difference without providing a pump or the like in the middle of the ink pipe 54.

When printing is performed, 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 above-mentioned piezo element in response to a command from the control unit 40. , Ink droplets are ejected from the ink nozzle 211.

Here, as ink droplets are consumed by the ink nozzle 211 due to printing, the thickness of the ink pouch 110 in the horizontal direction gradually decreases. More specifically, in the upper part of the ink pouch 110, the front surface and the back surface of the flexible packaging material are gradually brought close to each other, so that the horizontal thickness of the ink pouch 110 becomes thinner as the amount of ink consumed increases. Therefore, even if the ink is consumed, the liquid level position of the ink in the ink pouch 110 does not change significantly. That is, if a general ink tank is used as the ink supply source, the liquid level position of the ink in the ink tank decreases linearly as the ink is consumed, but the ink is used as the ink supply source as in the present embodiment. When the pouch 110 is used, the speed of lowering the liquid level position of the ink becomes slow. Therefore, even if the printing process progresses, the head difference between the liquid level of the ink in the ink pouch 110 and the ejection surface 210 can be kept within an allowable range for a long period of time. As a result, it is not necessary to frequently interrupt the printing process for replenishing ink or the like, and printing can be performed efficiently.

In particular, in the present embodiment, the vertically downward side 110b of the ink pouch 110 attached to the ink pouch holding portion 51 has a shape that descends vertically downward as it approaches the pouch opening 110a. More specifically, the ink pouch 110 has a shape that tapers downward, and the amount of ink stored decreases toward the lower end. Therefore, the liquid level position of the ink is higher when the remaining amount of the ink is the same, as compared with the case where the ink pouch whose lower end portion is not tapered is used. Therefore, the time for which the liquid level position of the ink is maintained at a height at which the above-mentioned head difference is within an allowable range can be lengthened. Therefore, even if the printing process progresses, the head difference between the liquid level of the ink in the ink pouch 110 and the ejection surface 210 can be properly maintained for a long period of time. Further, the shape of the side 110b and the mounting bottom surface 513d can promote the movement of the ink in the ink pouch 110 toward the ink discharge port 514. In FIG. 5, the direction in which the ink moves is indicated by a white arrow. Therefore, when the amount of ink remaining in the ink pouch 110 is low, it is unlikely that the remaining ink will be divided in the vertical direction.

When the remaining amount of ink in the ink pouch 110 is low, the first side surface portion 512 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, conventionally, when the ink pouch is attached / detached due to a decrease in the remaining amount of ink in the ink pouch, air bubbles may be mixed in the ink pipe. When large bubbles are mixed in the ink pipe, it is difficult to degas by a degassing filter or the like, and there is a risk that printing defects such as print omission may occur due to these bubbles. In this respect, in the present embodiment, by optimizing the inclination of the discharge port 514 and the positional relationship between the discharge port 514 and the second pipe 543, it is possible to prevent air bubbles from being mixed into the ink pipe 54. There is.

Specifically, the discharge port 514 and the short side of the second pipe 543 are connected in an inclined straight line inclined with respect to the horizontal direction, and the discharge port 514 is arranged at a higher position. Therefore, the air bubbles mixed during the attachment / detachment of the ink pouch 110 flow not to the side of the second pipe 543 but to the base end side of the discharge port 514. That is, the position of the discharge port 514 in the vertical direction is higher than the position of the bent portion 543a, which is the lowest point in the vertical direction of the ink pipe 54, in the vertical direction. Therefore, the bubbles having a specific gravity lighter than that of the ink naturally flow toward the discharge port 514.

<3. Summary>
As shown above, the ink supply unit (ink supply unit) 50 provided in the tablet printing apparatus (printing apparatus) 1 according to the present embodiment includes a recording head 21, an ink pouch holding portion 51, and an ink pipe 54. To be equipped. The ink pouch holding portion 51 includes a tubular discharge port 514 that discharges the ink in the ink pouch 110 toward the recording head 21. The discharge port 514 is arranged so as to be inclined with respect to the horizontal direction. The tip of the discharge port 514 moves vertically downward as the distance from the ink pouch 110 increases. As a result, air bubbles mixed in the vicinity of the discharge port 514 when the ink pouch 110 is attached / detached can easily escape to the inside of the ink pouch 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.

Further, in the ink supply unit 50 according to the present embodiment, the other end of the ink pipe 54 (second pipe 543) is connected in a straight line with the tip end portion of the discharge port 514. As a result, air bubbles mixed in the vicinity of the discharge port 514 when the ink pouch 110 is attached / detached can easily escape to the inside of the ink pouch 110 through the discharge port 514 rather than the inside of the ink pipe 54.

Further, in the ink supply unit 50 according to the present embodiment, the bent portion 543a, which is the middle portion of the ink pipe 54 and whose direction is changed by the internal flow path, 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 pouch 110 is attached / detached can easily escape to the inside of the ink pouch 110.

Further, in the ink supply unit 50 according to the present embodiment, the bent portion 543a 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 when the ink pouch 110 is attached / detached can more easily escape to the inside of the ink pouch 110.

Further, in the ink supply unit 50 according to the present embodiment, the discharge port 514 is located vertically below the discharge surface 210 of the recording head 21. As a result, for example, the discharge port 514 and the discharge surface 210 are arranged so that the position of the discharge surface 210 in the vertical direction is higher than the liquid level position of the ink enclosed in the ink pouch 110 in the vertical direction by a predetermined amount. By setting the positional relationship of the above in the vertical direction, it is possible to properly hold the meniscus in the ink nozzle.

Further, the ink pouch holding portion 51 according to the present embodiment has a pair of side surfaces extending vertically upward from the mounting bottom surface 513d. The ink pouch 110 is sandwiched from both sides by the pair of side surfaces. As a result, the ink pouch 110 is received from below by the mounting bottom surface 513d, and is sandwiched between the pair of side surfaces from both sides. Then, it becomes easy to gradually reduce the thickness of the ink pouch 110 in the horizontal direction as the ink is consumed. As a result, even if the ink is consumed, the liquid level position of the ink in the ink pouch 110 does not fluctuate so much.

Further, in the ink supply unit 50 according to the present embodiment, the mounting bottom surface 513d has an inclined plane shape that gradually lowers vertically downward as it approaches the discharge port 514. As a result, the movement of the ink in the ink pouch 110 to the discharge port 514 side can be promoted, so that when the remaining amount of ink in the ink pouch 110 is low, the remaining ink is divided in the vertical direction. Such a situation is less likely to occur.

Further, as shown in FIG. 5, the ink pouch holding portion 51 according to the present embodiment has a shape longer in the horizontal direction than in the vertical direction. As a result, the difference between the vertical position of the discharge surface 210 and the vertical position of the ink encapsulated in the ink pouch 110 in the vertical direction is within a predetermined allowable range (ideal head difference). A large amount of ink can be loaded. As a result, the frequency of interruption of the printing process for replenishing ink or the like can be suppressed, and continuous printing can be performed.

Further, the ink supply unit 50 according to the present embodiment further includes a support member 53 in which the recording head 21 is supported at one end and the ink pouch holding portion 51 is supported at the other end. As a result, the ink pouch 110 is arranged in a pre-positioned state so that the difference between the liquid level position of the ink in the vertical direction and the position of the ejection surface 210 in the vertical direction is kept within an allowable range. It becomes easy.

Further, in the ink supply unit 50 according to the present embodiment, the unit including the recording head 21, the ink pouch holding portion 51, the ink pipe 54, and the support member 53 is used for other configurations of the tablet printing device 1. It is integrally removable. As a result, the ink supply unit 50 in a state where the relative relationship between the position of the ejection surface 210, the position of the ink pouch holding portion 51, and the position of the ink pipe 54 in the vertical direction is properly set is handled as a unit. It becomes possible. Therefore, for example, by preparing such a unit for each of different types of ink in advance, it is possible to print by using a plurality of types of ink properly by attaching and detaching the unit and replacing the unit.

<4. About modification>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made to the above-described ones as long as the gist of the present invention is not deviated. It is possible.

In the above embodiment, the ink pouch 110 has a rectangular shape when viewed in the transport direction, but is not limited to this. For example, the shape of the ink pouch is trapezoidal or triangular when viewed in the transport direction. And so on.

In the above embodiment, the ink pouch 110 having a predetermined shape (capacity) can be attached to the ink pouch holding portion 51, but the present invention is not limited to this. Instead of the above, ink pouches having different capacities may be selectively attached to the ink pouch holding portion 51.

In the above embodiment, it is assumed that the recess 513a for accommodating the ink pouch 110 is provided only on the second side surface portion 513 of the ink pouch holding portion 51, but the present invention is not limited to this. Instead of the above, both the first side surface portion 512 and the second side surface portion 513 of the ink pouch holding portion 51 may be provided with recesses for accommodating the ink pouch 110.

Further, the elements appearing in the above-described embodiments and modifications may be appropriately combined as long as there is no contradiction.

1 Tablet printing device 9 Tablets 10 Tablet transport mechanism 14 Suction hole 15 Suction mechanism 16 Blow mechanism 20 Printing unit 21 Recording head 40 Control unit 50 Ink supply unit (ink supply unit)
51 Ink pouch holder 53 Support member 54 Ink piping 60 Ink supply unit movement mechanism 62 Vertical movement mechanism 63 Movement stage 64 Horizontal movement mechanism 91 Carry-in mechanism 92 Carry-out mechanism 95 Partition 110 Ink pouch 110a Pouch port 110b Side 210 Discharge surface 211 Ink nozzle 512 1st side surface part 513 2nd side surface part 513a Recessed 513d Mounting bottom surface 514 Outlet 541 1st pipe 542 Joint part 543 2nd pipe 543a Bent part

Claims (13)

An ink supply unit provided in a printing device that prints on the surface of a recording medium by an inkjet method.
A recording head having an ejection surface in which a plurality of ink nozzles for ejecting ink droplets are arranged,
An ink pouch holding portion capable of holding an ink pouch in which ink supplied to the recording head is sealed in a flexible packaging material, and includes a tubular discharge port for discharging the ink in the ink pouch toward the recording head. Ink pouch holder and
An ink pipe that is cylindrical, one end connected to the recording head and the other end connected to the outlet.
With
The outlet is arranged so as to be inclined with respect to the horizontal direction.
The tip of the discharge port moves vertically downward as the distance from the ink pouch increases.
Ink supply unit. The ink supply unit according to claim 1.
The other end of the ink pipe is an ink supply unit connected in a straight line with the tip of the discharge port. The ink supply unit according to claim 1 or 2.
The bent portion in the middle of the ink pipe where the internal flow path changes direction is an ink supply portion located vertically below the discharge port. The ink supply unit according to claim 3.
The bent portion is an ink supply portion located on the most vertically downward side of the ink pipe. The ink supply unit according to claim 3 or 4.
The discharge port is an ink supply unit located vertically below the discharge surface of the recording head. The ink supply unit according to any one of claims 3 to 5.
The ink pouch holding unit is an ink supply unit having a mounting bottom surface that receives the ink pouch from below. The ink supply unit according to claim 6.
The ink pouch holding portion has a pair of side surfaces extending vertically upward from the previously described bottom surface.
An ink supply unit in which the ink pouch is sandwiched from both sides by the pair of side surfaces. The ink supply unit according to claim 6 or 7.
The above-mentioned mounting bottom surface is an ink supply unit having an inclined flat surface that gradually lowers vertically downward as it approaches the discharge port. The ink supply unit according to claim 5.
The ink pouch holding portion is an ink supply portion having a shape longer in the horizontal direction than in the vertical direction. The ink supply unit according to any one of claims 1 to 9.
An ink supply unit further provided with a support member, wherein the recording head is supported at one end and the ink pouch holding portion is supported at the other end.
The ink supply unit according to claim 10.
An ink supply unit in which a unit including the recording head, the ink pouch holding unit, the ink pipe, and the support member is integrally removable from other configurations of the printing apparatus. A printing apparatus comprising the ink supply unit according to any one of claims 1 to 11. A tablet printing apparatus comprising the ink supply unit according to any one of claims 1 to 11, and printing on the surface of a tablet as a recording medium by an inkjet method.

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