CN110936730A

CN110936730A - Ink supply unit, printing device, tablet printing device, and ink bag

Info

Publication number: CN110936730A
Application number: CN201910822553.8A
Authority: CN
Inventors: 中野信行; 西川贵之; 山本昌宏; 高畑侑弥; 伊藤尚充
Original assignee: Screen Holdings Co Ltd
Current assignee: Screen Holdings Co Ltd
Priority date: 2018-09-21
Filing date: 2019-08-30
Publication date: 2020-03-31
Anticipated expiration: 2039-08-30
Also published as: JP7319768B2; KR20200034566A; KR102256809B1; CN110936730B; JP2020044290A

Abstract

The invention provides an ink supply part, which can reduce the frequency of interrupting printing processing due to ink supplement and the like, thereby continuously printing. An ink supply unit (ink supply section) (50) is provided in a tablet printing apparatus (printing apparatus) that performs printing on the surface of a tablet (recording medium) (9) by an inkjet method, and the ink supply unit (50) has a recording head (21) and an ink bag holding section (51). The recording head (21) has an ejection surface (210) on which a plurality of ink nozzles (211) for ejecting ink droplets are arranged. The ink bag holding section (51) can be connected to the recording head (21) and can hold an ink bag in which ink supplied to the recording head (21) is sealed in a flexible packaging material. The recording head (21) and the ink bag holding portion (51) are positioned and arranged so that the difference between the position of the ejection surface (210) in the vertical direction and the position of the liquid surface of the ink sealed in the ink bag in the vertical direction is within a predetermined allowable range.

Description

Ink supply unit, printing device, tablet printing device, and ink bag

Technical Field

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

Background

Conventionally, a printing apparatus having a recording head and an ink cartridge is known. The recording head has an ejection face on which a plurality of ink nozzles for ejecting ink droplets are arrayed. The ink cartridge stores ink supplied to the recording head. In the field of printing apparatuses, the following printing apparatuses are widely known as a printing apparatus of a slide carriage type: the recording head and the ink cartridge are mounted on the same carriage, and printing is performed while the recording head and the ink cartridge are moved integrally. The printing device of the loading sliding frame type has the advantages of simple structure and low possibility of influencing the ink nozzle by external interference.

However, in order to accurately discharge ink droplets and perform printing delicately, it is necessary to appropriately maintain the meniscuses in the respective ink nozzles, and therefore, it is necessary to maintain the difference between the position in the vertical direction of the discharge surface and the position in the vertical direction of the liquid surface of the ink in the ink cartridge (hereinafter, sometimes referred to as "water head difference") within a predetermined range. For this reason, conventionally, measures such as the following have been taken: an allowable range of the height of the liquid surface of the ink in the ink cartridge is set in advance, and if the liquid surface of the ink is lower than the lower limit position, the ink is replenished to the upper limit position. Therefore, interruption of the printing process for ink replenishment often occurs, and it is difficult to continuously perform printing.

To cope with this problem, a printing apparatus as disclosed in patent document 2 has been devised. The printing apparatus described in patent document 2 includes an inkjet head (recording head), an ink cartridge, and a moving device. The moving device described in patent document 2 changes the height of the ink cartridge in accordance with the amount of ink used, which is grasped in advance, so that the difference in water level between the height of the liquid surface of the ink in the ink cartridge and the nozzle forming surface (ejection surface) on which the nozzles are formed is maintained at a predetermined value.

According to the printing apparatus described in patent document 2, the difference in water level can be maintained within the allowable range for a long time by changing the height of the ink cartridge, and the frequency of interruption of the printing process due to ink replenishment or the like can be reduced. However, the printing apparatus described in patent document 2 has a disadvantage in that the apparatus is large in size due to the presence of the moving device. The printing apparatus described in patent document 2 also has a disadvantage that the influence of disturbance of the ink nozzles is large.

Patent document 1: international publication No. 2016/159096

Disclosure of Invention

The present invention has been made in view of the above circumstances, and a potential object thereof is to reduce the frequency of interruption of printing processing due to ink replenishment or the like, and to enable continuous printing.

The problems to be solved by the present invention are as described above, and the technical means for solving the problems will be described below.

A first aspect of the present invention provides an ink supply unit provided in a printing apparatus that performs printing on a surface of a recording medium by an inkjet method, the ink supply unit including: a recording head having an ejection surface on which a plurality of ink nozzles for ejecting ink droplets are arrayed; and an ink bag holding portion that is connectable to the recording head and that can hold an ink bag in which ink supplied to the recording head is sealed in a flexible packaging material, wherein the recording head and the ink bag holding portion are positioned and arranged such that a difference between a position in a vertical direction of the ejection surface and a liquid surface position in the vertical direction of the ink sealed in the ink bag is within a predetermined allowable range.

In a second aspect of the present invention, in the ink supply unit according to the above aspect, the ink bag holding portion has a placement bottom surface for receiving the ink bag from below.

In a third aspect of the present invention, in the ink supply unit according to the above aspect, the ink bag holding portion has a pair of side surfaces extending vertically upward from the placement bottom surface, and the ink bag is sandwiched between the pair of side surfaces from both sides.

A fourth aspect of the present invention provides the ink supply unit of the above aspect, wherein the ink bag holding portion further includes a discharge port that discharges ink in the ink bag toward the recording head, and the placement bottom surface is an inclined plane that gradually descends vertically downward as it approaches the discharge port.

A fifth aspect of the present invention provides the ink supply unit of the above aspect, wherein an inclination angle of the mounting bottom surface is 5 ° or more and 15 ° or less with respect to a horizontal direction. .

A sixth aspect of the present invention provides the ink supply unit of the above aspect, wherein an inclination angle of the placement bottom surface is 8 ° or more and 12 ° or less with respect to a horizontal direction. .

A seventh aspect of the present invention provides the ink supply unit of the above aspect, wherein the ink bag holding portion can selectively attach the ink bags of different capacities.

An eighth aspect of the present invention provides the ink supply unit of the above aspect, wherein the ink supply unit further includes a support member that supports the recording head at one end portion and supports the ink bag holding portion at the other end portion.

A ninth aspect of the present invention provides the ink supply unit of the above aspect, wherein the ink supply unit further includes a pipe that supplies the ink in the ink bag to the recording head.

A tenth aspect of the present invention provides the ink supply unit of the above aspect, wherein a unit including the recording head, the ink bag holding unit, the support member, and the pipe is integrally detachable from another structure of the printing apparatus.

An eleventh aspect of the present invention provides a printing apparatus having the ink supply unit according to the above aspect.

A twelfth aspect of the present invention provides a tablet printing apparatus that performs printing by an inkjet method on a surface of a tablet as the recording medium, the tablet printing apparatus including the ink supply unit according to the above-described aspect.

A thirteenth aspect of the present invention provides an ink bag attached to the ink bag holding portion of the ink supply portion of the above-described aspect. The ink bag has a bag opening for discharging the ink therein at an end portion on a vertically lower side, and a side of the ink bag on the vertically lower side is inclined so as to gradually descend vertically downward as approaching the bag opening.

According to the first to thirteenth aspects of the present invention, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed.

In particular, according to the first aspect of the present invention, when ink is consumed in printing, the thickness of the ink bag in the horizontal direction gradually becomes thinner. Therefore, even if the ink is consumed, the liquid surface position of the ink in the ink bag does not greatly change. Thus, even when the printing process is performed, the difference between the liquid surface position in the vertical direction of the ink in the ink bag and the position in the vertical direction of the ejection surface can be appropriately maintained for a long time. As a result, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed. Further, since the ink supply unit of the present configuration is of a slide carriage type, the influence of external interference of the ink nozzle can be reduced.

In particular, according to the third aspect of the present invention, the ink bag is received from below by the placement bottom surface and is sandwiched from both sides by the pair of side surfaces, so that the thickness of the ink bag in the horizontal direction gradually becomes thinner as the ink is consumed. Thus, even if ink is consumed, the liquid surface position of the ink in the ink bag hardly changes.

In particular, according to the fourth aspect of the present invention, the manner of lowering the liquid surface position in the vertical direction of the ink in the ink bag becomes slower as the ink is consumed. This makes it possible to maintain the difference between the liquid surface position in the vertical direction of the ink in the ink bag and the position in the vertical direction of the ejection surface within the allowable range for a long period of time. As a result, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed. Further, since the ink in the ink bag can be promoted to move toward the discharge port side, when the remaining amount of the ink in the ink bag becomes small, the remaining ink is less likely to be interrupted in the vertical direction.

In particular, according to the seventh aspect of the present invention, it is possible to install an ink bag having an appropriate capacity in accordance with the amount of ink required to perform printing, and thus it is possible to realize low-cost operation of the printing apparatus.

In particular, according to the eighth aspect of the present invention, it is easy to arrange the ink bag in a predetermined position so that the difference between the position of the liquid surface in the vertical direction of the ink in the ink bag and the position in the vertical direction of the ejection surface is maintained within the allowable range.

In particular, according to the ninth aspect of the present invention, since the difference between the liquid surface position in the vertical direction of the ink in the ink bag and the position in the vertical direction of the ejection surface is maintained within the allowable range, the ink can be supplied to the ink nozzle by the difference in water level without providing a pump or the like in the middle of the piping.

In particular, according to the tenth aspect of the present invention, it is possible to unitize the ink supply portion in a state where a specific relative relationship in the vertical direction between the position of the ejection surface and the position of the ink bag holding portion has been appropriately set. Thus, for example, such a unit is prepared for each different type of ink, and the unit is attached and detached and replaced, thereby facilitating printing using a plurality of types of ink in a differentiated manner.

In particular, according to the thirteenth aspect of the present invention, as the ink is consumed, the manner in which the liquid surface position in the vertical direction of the ink in the ink bag is lowered becomes slow. This makes it possible to maintain the difference between the liquid surface position in the vertical direction of the ink in the ink bag and the position in the vertical direction of the ejection surface within the allowable range for a long period of time. As a result, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed. Further, since the ink in the ink bag can be promoted to move toward the discharge port, when the remaining amount of the ink in the ink bag becomes small, the remaining ink is less likely to be interrupted in the vertical direction.

Drawings

Fig. 1 is a schematic configuration diagram of a tablet printing apparatus.

Fig. 2 is a partial perspective view of the tablet conveying mechanism.

Fig. 3 is a bottom view of the recording head.

Fig. 4 is a side view of the ink supply portion.

FIG. 5 is a side view of an ink bag.

Description of the reference numerals:

1 tablet printing device (printing device)

9 tablet (recording medium)

21 recording head

50 ink supply unit (ink supply part)

51 ink bag holding part

110 ink bag

111 pocket mouth

112 edge of the side under the plumb

210 discharge surface

510 carrying bottom surface

512 side surface

513 side surface

514 discharge port

53 support member

54 piping

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the following description, a direction in which a plurality of tablets are conveyed is referred to as a "conveying direction", and a direction perpendicular to and horizontal to the conveying direction is referred to as a "width direction".

<1. overall Structure of tablet printing apparatus >

Fig. 1 is a diagram showing a configuration of a tablet printer (printer) 1 according to an embodiment of the present invention. The tablet printer 1 is a device that prints images such as a product name, a product number, a company name, and a brand mark on the surface of each tablet 9 while conveying a plurality of tablets 9 that are pharmaceutical products. As shown in fig. 1, the tablet printing apparatus 1 of the present embodiment includes a tablet conveying mechanism 10, a printing unit 20, a drying mechanism 30, and a control unit 40.

The tablet conveying mechanism 10 is a mechanism that conveys the plurality of tablets 9 while holding the plurality of tablets 9. The tablet conveying mechanism 10 includes a pair of pulleys 11 and an endless conveying belt 12 stretched between the pair of pulleys 11. The plurality of tablets 9 loaded into the tablet printing apparatus 1 are arranged at equal intervals by a loading mechanism 91 constituted by a vibrating feeder, a conveying roller, or the like, and are supplied to the outer peripheral surface of the conveying belt 12. One of the pair of pulleys 11 is rotated by power obtained from the conveyance motor 13. Thereby, the conveyor belt 12 rotates in the arrow direction in fig. 1. At this time, the other of the pair of pulleys 11 is driven to rotate in accordance with the rotation of the conveying belt 12.

Fig. 2 is a partial perspective view of the tablet conveying mechanism 10. As shown in fig. 2, the carrier belt 12 is provided with a plurality of suction holes 14. The plurality of suction holes 14 are arranged at equal intervals in the conveying direction and the width direction. As shown in fig. 1, the tablet conveying mechanism 10 includes a suction mechanism 15 for sucking gas from the space inside the conveying belt 12. When the suction mechanism 15 is operated, a negative pressure lower than the atmospheric pressure is formed in the space inside the conveyor belt 12. The plurality of tablets 9 are held in a state of being adsorbed to the adsorption holes 14 by 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 at the plurality of suction holes 14 at a constant interval. A plurality of tablets 9 are conveyed in the horizontal direction below the four recording heads 21 described later.

As shown in fig. 1, the tablet conveying mechanism 10 includes an air blowing mechanism 16 inside the conveying belt 12. When the air blowing mechanism 16 is operated, only the suction holes 14 facing the carrying-out mechanism 92 among the plurality of suction holes 14 of the conveyor belt 12 are pressurized to a positive pressure higher than the atmospheric pressure. Thereby, the adsorption of the tablets 9 on the adsorption holes 14 is released, and the tablets 9 are delivered from the conveyor belt 12 to the carrying-out mechanism 92. The carrying-out mechanism 92 carries out the tablets 9 joined from the conveyor belt 12 to the outside of the tablet printing apparatus 1 by, for example, another conveyor belt.

The printing unit 20 is a portion for recording an image on the surface of the tablet 9 conveyed by the conveyor belt 12 by an ink jet method. As shown in fig. 1, the printing unit 20 of the present embodiment includes four recording heads 21. Each recording head 21 is included in an ink supply unit 50 described later. The four recording heads 21 are positioned above the conveying belt 12 and arranged in a row along the conveying direction of the tablets 9. The four recording heads 21 eject ink droplets of mutually different colors (for example, cyan (cyan), magenta (magenta), yellow, and black colors) toward the surface of the tablet 9. In this way, a multicolor image is recorded on the surface of tablet 9 by superimposing monochromatic images formed by these colors. As the ink to be ejected from each recording head 21, edible ink made of a material approved by the japanese pharmacopoeia, the food hygiene law, or the like can be used.

Fig. 3 is a bottom view of one recording head 21. Fig. 3 shows the conveying belt 12 and a plurality of tablets held by the conveying belt 12 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 which is the lower surface of the recording head 21. In the present embodiment, a plurality of ink nozzles 211 are two-dimensionally arranged along the conveyance direction and the width direction on the lower surface of the recording head 21. The ink nozzles 211 are arranged offset in the width direction. In this way, if the plurality of ink nozzles 211 are two-dimensionally arranged, the positions of the ink nozzles 211 in the width direction can be made close to each other. However, the plurality of ink nozzles 211 may be arranged in a row along the width direction.

As a method of discharging ink droplets discharged from the ink nozzles 211, for example, a so-called piezoelectric method is used, in which ink in the ink nozzles 211 is pressurized and discharged by applying a voltage to a piezoelectric element (piezoelectric element) as a piezoelectric device to deform the piezoelectric element. However, the ink droplet discharge method may be a so-called thermal method in which the ink in the ink nozzle 211 is heated and expanded by energizing a heater to discharge the ink.

Returning to fig. 1. 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 conveyor belt 12 at a position downstream of the printing unit 20 in the conveying direction. As the drying mechanism 30, for example, a hot air supply mechanism that blows heated gas (hot air) to the tablet 9 conveyed by the conveying belt 12 is used. The ink adhering to the surface of tablet 9 is dried by hot air and fixed to the surface of tablet 9.

The control unit 40 is a mechanism for controlling the operation of each unit in the tablet printing apparatus 1. The control unit 40 is constituted by a computer having a processor such as a CPU, a memory such as a RAM, and a storage unit such as a hard disk drive. A computer program for executing the printing process is installed in the storage unit of the control unit. The control unit 40 is communicably connected to the conveyance motor 13, the suction mechanism 15, the blower mechanism 16, the four recording heads 21, the drying mechanism 30, the carrying-in mechanism 91, and the carrying-out mechanism 92, respectively. The control unit 40 is also communicably connected to a vertical movement mechanism 62 and a horizontal movement mechanism 64, which will be described later. The control unit 40 temporarily reads the computer program and data stored in the storage unit into the memory, and the processor performs arithmetic processing based on the computer program to control the operations of the respective units by cooperation of hardware and software. Thereby, the printing process for the plurality of tablets 9 is performed.

<2 > details of the printing section

Fig. 4 is a side view of the printing portion 20 viewed only from the position of the white hollow arrow V in fig. 1. 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 a 2. The printing area a1 is an area where the tablet 9 is printed while the tablet 9 is conveyed by the tablet conveying mechanism 10. The maintenance area a2 is an area where the recording head 21 is caused to stand by before or after printing, the discharge surface 210 of the recording head 21 is cleaned, or the ink supply unit 50 described later is replaced. A partition wall 95 separating the two areas is provided between the printing area a1 and the maintenance area a 2. The partition wall 95 extends parallel to the conveying direction of the tablets 9 and perpendicular to the horizontal plane.

As described above, the printing section 20 has the four recording heads 21. In addition, as shown in fig. 4, each recording head 21 of the printing portion 20 has an ink supply unit 50. Further, the ink supply unit 50 also includes the recording head 21 itself. The printing unit 20 includes an ink supply unit moving mechanism 60 corresponding to each recording head 21 (ink supply unit 50) and a total of four cleaning units 71 corresponding to each recording head 21.

<2-1 > regarding the ink supply unit

The ink supply unit 50 supplies ink to the printing portion 20. As described above, the ink supply unit 50 is provided to each recording head 21. The ink supply unit 50 includes an ink bag holding portion 51, a joint portion 52, a support member 53, and a pipe 54 in addition to the recording head 21.

The ink bag holding portion 51 is a holder capable of holding an ink bag 110, and the ink bag 110 seals ink supplied to the recording head 21 into a flexible packaging material. The ink bag holding portion 51 can be connected to the recording head 21. Specifically, the ink bag holding portion 51 mainly includes a mounting bottom surface 510, a pair of side surfaces 512 and 513, and a discharge port 514.

The pair of side surfaces 512 and 513 are plate-shaped portions extending vertically upward from the placement bottom surface 510. The pair of side surfaces 512 and 513 are arranged to form a plane perpendicular to the conveying direction. A recess 512a along the shape of the ink bag 110 is provided on the side surface 512 on the upstream side in the conveying direction of the pair of side surfaces 512 and 513. The concave portion 512a is recessed toward the upstream side in the conveying direction. On the other hand, the side surface 513 on the downstream side in the conveying direction is formed in a cover shape capable of covering the recess 512 a.

The placement bottom surface 510 forms a surface below the concave portion 512 a. The mounting bottom surface 510 is a plate-like portion that receives the ink bag 110 accommodated in the ink bag holding portion 51 from the lower side. The placement bottom surface 510 is an inclined plane surface that gradually descends vertically downward as it approaches a discharge port 514 described later. The inclination angle of the placement bottom surface 510 with respect to the horizontal direction is preferably 5 ° or more and 15 ° or less, more preferably 8 ° or more and 12 ° or less, and still more preferably 10 °. The mounting bottom surface 510 has a thin shape in the conveying direction.

Side surface 513 is detachable from side surface 512 by a fastening member such as a screw. When the side surface 513 is attached to the side surface 512 in a state where the recess 512a accommodates the ink bag 110, the ink bag 110 can be held in the ink bag holding portion 51.

The discharge port 514 is a cylindrical portion that discharges ink in the ink bag 110 toward the recording head 21. One end of the discharge port 514 is an end portion on the vertically lower side of the concave portion 512a, and is connected to the vicinity of the lowest position of the placement bottom surface 510. The other end of the discharge port 514 is disposed at a position closer to the recording head 21 than the one end of the discharge port 514.

One end of the joint portion 52 is connected to the other end of the discharge port 514. The other end of the joint 52 is connected to a pipe 54. The pipe 54 is a tube connecting the other end of the joint portion 52 and the ink nozzle 211 of the recording head 21. Thus, the piping 54 can supply the ink in the ink bag 110 to the recording head 21.

The support member 53 has a plate shape perpendicular to the conveying direction, and has a shape elongated in the width direction. One end portion in the width direction of the support member 53 supports the recording head 21. The other end portion in the width direction of the support member 53 supports the ink bag holding portion 51. Specifically, the recording head 21 and the ink bag holding portion 51 are positioned and fixed to the support member 53 such that the difference between the position of the discharge surface 210 of the recording head 21 in the vertical direction and the position of the liquid surface of the ink sealed in the ink bag 110 in the vertical direction is within a predetermined allowable range. In other words, when the ink bag 110 is attached to the ink bag holding portion 51, the relative position in the vertical direction between the recording head 21 and the ink bag holding portion 51 is determined by the support member 53 so that the water head difference between the liquid surface position in the ink bag 110 and the liquid surface position of the ink on the ejection surface 210 is a water head difference of such a degree that an appropriate meniscus can be held in each ink nozzle 211.

The recording head 21, the ink bag holding portion 51, the joint portion 52, the support member 53, and the pipe 54 are combined and unitized as an ink supply unit 50. That is, the ink supply unit 50 is integrally attachable to and detachable from the other structure of the tablet printer 1. In the present embodiment, such an ink supply unit 50 is prepared in advance for different types of ink. Thus, by attaching and detaching the replacement ink supply unit 50, it is possible to print by using a plurality of kinds of inks separately.

<2-2 > regarding the ink bag >

The ink bag 110 shown in fig. 5 is an ink supply source held by the ink bag holding portion 51 described above. That is, in the present invention, the ink bag 110 is used as an ink supply source instead of the conventional ink cartridge. Fig. 5 is a side view showing the structure of the ink bag 110.

The ink bag 110 is a member for enclosing ink in a flexible packaging material. The ink bag 110 can be easily deformed in a direction in which the surface approaches or separates from the back surface. When viewed in a posture in which the ink bag 110 is attached to the ink bag holding portion 51, a bag opening 111 for pouring out (discharging) ink inside is provided at an end portion on a vertically lower side of the ink bag 110. The ink bag 110 is thin in the conveyance direction, and has a trapezoidal shape when viewed in the conveyance direction. The side 112 of the ink bag 110 on the vertical lower side is inclined so as to gradually descend vertically downward as it approaches the bag opening 111.

<2-3 > moving mechanism for ink supply unit >

Returning to fig. 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 a 2. 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 by mounting a slide carriage. The ink supply unit moving mechanism 60 of the present embodiment includes an arm 61, a vertical moving mechanism 62, a moving table 63, and a horizontal moving mechanism 64. The arm portion 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 vertically in accordance with a command from the control unit 40. Thereby, as shown by an arrow D1 in fig. 4, the arm portion 61 moves up and down integrally with the ink supply unit 50 including the recording head 21. This allows the position of the ejection surface 210 in the vertical direction to be adjusted according to the thickness of the tablet 9 to be printed. In the maintenance area a2, the cleaning unit 71 can be caused to act on the discharge surface 210 of the recording head 21 by lowering the recording head 21 by the vertical movement mechanism 62. This enables cleaning and maintenance of the ejection surface 210.

The up-down moving mechanism 62 is supported by a moving table 63. The horizontal movement mechanism 64 moves the movement table 63 in the width direction. Thereby, the movable table 63, the vertical movement mechanism 62, the arm 61, and the ink supply unit 50 are integrally formed, and move in the width direction as indicated by an arrow D2 in fig. 4. The horizontal movement mechanism 64 and the vertical movement mechanism 62 can use a mechanism that converts rotational motion of a motor into linear motion by a ball screw, for example. 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-described configuration, the recording head 21 and the supporting member 53 are attached to the arm portion 61, and the ink supply unit 50 is mounted on the printing portion 20. The ink bag 110 can be attached to the ink bag holding portion 51 in a state where the recording head 21 is moved by the horizontal movement mechanism 64 from a position above the transport belt 12 to a position farthest away in the width direction. Thus, a sufficient space for the operator to perform the mounting operation can be secured at a position spaced apart from the conveyor belt 12 in the width direction.

The ink bag 110 may be attached to the ink bag holding portion 51 as follows. That is, first, the operator removes the side surface 513 from the ink bag holding portion 51 by removing the fastening member. Then, the operator fits the ink bag 110 into the recess 512a while keeping the bag opening 111 of the ink bag 110 connected to the discharge port 514. At this time, the side 112 of the ink bag 110 on the vertically lower side is received from below by the placement bottom surface 510. In this state, the operator installs side 513 against side 512 by retightening the fastening member. This forms a state in which the ink bag 110 is sandwiched by the pair of side surfaces 512 and 513 from both sides.

Thus, the ink is supplied to each ink nozzle 211 through the joint 52 and the pipe 54 by the water pressure from the ink bag 110. At this time, in the ink supply unit 50, since the relative relationship in the vertical direction between the position of the ejection surface 210 and the position of the ink bag holding portion 51 is appropriately set, there is no risk that ink droplets may drop from the ejection surface 210. That is, an appropriate meniscus is maintained in each ink nozzle 211. Further, since the relative relationship between the position of the discharge surface 210 and the position of the ink bag holding portion 51 in the vertical direction is appropriately set, the ink does not flow backward from the recording head 21 toward the ink bag 110, and air does not enter the recording head 21.

With the above configuration, in the tablet printer 1 according to the present embodiment, since the difference between the liquid surface position in the vertical direction of the ink in the ink bag 110 and the position in the vertical direction of the discharge surface 210 is maintained within the allowable range, the ink can be supplied to the ink nozzle 211 by the difference in water level without providing a pump or the like in the middle of the pipe 54.

When printing is performed, the recording head 21 is placed at a position above the transport belt 12 by the horizontal movement mechanism 64, and a voltage is applied to the piezoelectric element in accordance with a command from the control unit 40, thereby discharging ink droplets from the ink nozzles 211.

Here, when ink droplets are consumed at the ink nozzles 211 by performing printing, the horizontal thickness of the ink bag 110 gradually becomes thinner. Specifically, the top of the ink bag 110 is in a state where the front surface and the back surface of the flexible packaging material are gradually close to each other, and the horizontal thickness of the ink bag 110 becomes thinner as the amount of ink consumed increases. Therefore, even if the ink is consumed, the liquid surface position of the ink in the ink bag does not greatly change. That is, in the case where a conventional ink cartridge is assumed to be used as the ink supply source, the liquid surface position of the ink in the ink cartridge linearly decreases as the ink is consumed, but, as described in the present embodiment, in the case where the ink bag 110 is used as the ink supply source, the speed of decrease in the liquid surface position of the ink becomes slow. Thus, even when the printing process is performed, the difference in water level between the liquid surface of the ink in the ink bag 110 and the ejection surface 210 can be maintained within the allowable range for a long time. As a result, the printing process can be prevented from being frequently interrupted by ink replenishment or the like, and printing can be efficiently performed.

In particular, the side 112 of the ink bag 110 of the present embodiment on the vertical lower side is shaped so as to descend toward the bag opening 111 on the vertical lower side. Specifically, the ink bag 110 is tapered downward, and the amount of ink stored decreases toward the lower portion. Therefore, the liquid surface position of the ink becomes higher when the remaining amount of the ink is the same as compared with the case where the ink bag having a shape not becoming thinner downward is used. Therefore, the liquid surface position of the ink can be maintained at the specific height within the allowable range for a longer period of time. Thus, even when the printing process is performed, the water level difference between the liquid surface of the ink in the ink bag 110 and the ejection surface 210 can be appropriately maintained for a long time. Further, the movement of the ink in the ink bag 110 to the discharge port 514 side can be promoted by the shape of the side 112 and the placement bottom surface 510. The direction of ink movement is shown by the white open arrows in fig. 5. Therefore, when the remaining amount of ink in the ink bag 110 is reduced, the remaining ink is less likely to be interrupted in the vertical direction.

If the amount of ink remaining in the ink bag 110 is small, the side surface 513 of the ink bag holding portion 51 can be attached and detached to replace the new ink bag 110 in the same manner as described above.

The tablet printing apparatus 1 of the present embodiment can be used for printing a plurality of types of tablets 9 having different surface coating layer materials. When tablets 9 having different materials for the surface coating are printed, the type of ink used for printing is generally different. Therefore, in the tablet printing apparatus 1, it is necessary to use a plurality of kinds of inks in different ways depending on the kind of the tablet 9 to be printed. In this regard, in the tablet printing apparatus 1 according to the present embodiment, the ink supply unit 50 for a certain type of ink is detached from the arm 61, and the ink supply unit 50 for another type of ink is newly attached to the arm 61, whereby the use of ink can be easily distinguished. In this case, it is not necessary to introduce a cleaning liquid or the like into the joint portion 52 and the pipe 54 for cleaning in order to prevent mixing of ink, and thus the labor time and burden of the operator and the time and cost required for maintenance can be significantly reduced.

As described above, the ink supply unit (ink supply portion) 50 of the present embodiment includes the recording head 21 and the ink bag holding portion 51. The recording head 21 and the ink bag holding portion 51 are positioned and arranged so that the difference between the position of the discharge surface 210 in the vertical direction and the position of the liquid surface of the ink sealed in the ink bag 110 in the vertical direction falls within a predetermined allowable range. In the ink supply unit 50 having this configuration, when ink is consumed by printing, the thickness of the ink bag 110 in the horizontal direction gradually becomes thinner. Therefore, even if ink is consumed, the difference between the liquid surface position in the vertical direction of the ink in the ink bag 110 and the position in the vertical direction of the discharge surface 210 can be appropriately maintained for a long time. As a result, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed.

In the ink supply unit 50 of the present embodiment, the ink bag 110 is received from below by the loading bottom surface 510, and the ink bag 110 is sandwiched from both sides by the pair of side surfaces 512 and 513. This makes it easy to gradually reduce the thickness of the ink bag 110 in the horizontal direction as the ink is consumed. Thus, even if ink is consumed, the liquid surface position of the ink in the ink bag hardly changes.

In the ink supply unit 50 of the present embodiment, the mounting bottom surface 510 is an inclined plane surface that gradually descends in the vertical direction as it approaches the discharge port 514. The inclination angle of the placement bottom surface 510 is preferably 5 ° or more and 15 ° or less with respect to the horizontal direction, and more preferably 8 ° or more and 12 ° or less with respect to the horizontal direction. As a result, the manner of lowering the liquid surface position in the vertical direction of the ink in the ink bag 110 becomes slower as the ink is consumed. This allows the difference between the liquid surface position of the ink in the ink bag 110 in the vertical direction and the position of the discharge surface 210 in the vertical direction to be maintained within the allowable range for a longer period of time. As a result, the frequency of interruption of the printing process due to ink replenishment or the like can be reduced, and printing can be continuously performed. Further, since the ink in the ink bag 110 can be promoted to move toward the discharge port 514, when the remaining amount of the ink in the ink bag 110 is small, the remaining ink is not likely to be stopped in the vertical direction and remain on the upper portion of the ink bag 110.

In the ink supply unit 50 of the present embodiment, the ink packs 110 having different capacities can be selectively attached. Thus, the ink bag 110 having an appropriate capacity can be attached and printed according to the amount of ink used, and the printing apparatus can be applied at low cost.

In the ink supply unit 50 of the present embodiment, the recording head 21 is supported at one end of the support member 53, and the ink bag holding portion 51 is supported at the other end. This facilitates the arrangement in the pre-positioned state so that the difference between the liquid surface position in the vertical direction of the ink in the ink bag 110 and the position in the vertical direction of the discharge surface 210 is kept within the allowable range.

The ink supply unit 50 of the present embodiment is integrally detachable from the other components of the tablet printer 1. Thus, the ink supply unit 50 can be handled integrally in a state where a specific relative relationship in the vertical direction between the position of the discharge surface 210 and the position of the ink bag holding portion 51 is appropriately set. Thus, for example, such an ink supply unit 50 is prepared for each different type of ink, and the ink supply unit 50 is attached and detached and replaced, whereby printing can be performed using a plurality of types of ink with ease.

<3. modification >

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made to the above embodiments without departing from the spirit thereof.

In the above embodiment, the ink bag 110 has a trapezoidal shape when viewed from the conveying direction, but the present invention is not limited to this, and may have a rectangular shape when viewed from the conveying direction, for example. In this case, the long side of the rectangular ink bag may be placed on the inclined placement bottom surface 510.

In the above embodiment, it is set that the ink bag 110 having different capacities can be selectively attached to the ink bag holding portion 51, but the present invention is not limited thereto. Instead of this, only the ink bag 110 having a constant capacity may be attached to the ink bag holding portion 51.

In addition, the respective members appearing in the above-described embodiment or modification may be appropriately combined without contradiction.

Claims

1. An ink supply unit provided in a printing apparatus for printing on a surface of a recording medium by an ink jet method,

the ink supply unit includes:

a recording head having an ejection surface on which a plurality of ink nozzles for ejecting ink droplets are arrayed; and

an ink bag holding section connectable to the recording head and capable of holding an ink bag in which ink supplied to the recording head is sealed in a flexible packaging material,

the recording head and the ink bag holding portion are positioned and arranged so that a difference between a position in a vertical direction of the ejection surface and a position of a liquid surface of the ink sealed in the ink bag in the vertical direction is within a predetermined allowable range.

2. The ink supply according to claim 1,

the ink bag holding portion has a mounting bottom surface for receiving the ink bag from below.

3. The ink supply according to claim 2,

the ink bag holding portion has a pair of side surfaces extending vertically upward from the mounting bottom surface,

the ink bag is sandwiched from both sides by the pair of side surfaces.

4. The ink supply according to claim 3,

the ink bag holding portion further has a discharge port that discharges ink in the ink bag toward the recording head,

the placement bottom surface is an inclined plane shape that gradually descends vertically downward as it approaches the discharge port.

5. The ink supply according to claim 4,

the inclination angle of the carrying bottom surface is more than 5 degrees and less than 15 degrees relative to the horizontal direction.

6. The ink supply unit according to claim 5, wherein,

the inclination angle of the carrying bottom surface is more than 8 degrees and less than 12 degrees relative to the horizontal direction.

7. The ink supply section according to any one of claims 1 to 6,

the ink bag holding portion can selectively mount the ink bags of different capacities.

8. The ink supply section according to any one of claims 1 to 6,

the ink supply portion further has a support member that supports the recording head at one end portion and supports the ink bag holding portion at the other end portion.

9. The ink supply unit according to claim 8, wherein,

the ink supply unit further includes a pipe that supplies the ink in the ink bag to the recording head.

10. The ink supply according to claim 9,

the unit including the recording head, the ink bag holding portion, the support member, and the piping is integrally detachable with respect to other structures of the printing apparatus.

11. A printing apparatus having the ink supply unit according to any one of claims 1 to 10.

12. A tablet printing apparatus for printing on a surface of a tablet as the recording medium by an ink jet method, the tablet printing apparatus comprising the ink supply unit according to any one of claims 1 to 10.

13. An ink bag mounted on the ink bag holding portion of the ink supply portion according to any one of claims 1 to 10,

a bag opening for discharging the ink therein is provided at the end portion on the lower side of the vertical,

the edge of the ink bag on the vertically lower side is inclined so as to gradually descend vertically downward as the ink bag approaches the bag opening.