Printing system and printing method

Abstract

The invention provides a printing system and a printing method capable of performing high-quality printing. A printing system includes: a robot including a robot arm that supports and moves a print head that ejects ink; and an ink storage unit that stores the ink supplied to the print head, in which the ink storage unit is positioned on the upper side in the vertical direction relative to the movement range of the print head. In addition, the ink storage part and the robot are separately arranged. In addition, the printing system is provided with a pipeline connecting the ink storage part and the printing head.

Description

Technical Field

[0001] The present invention relates to a printing system and a printing method. Background Art

[0002] In the printing system described in Patent Document 1, printing on an object is performed by ejecting ink toward the object while moving a robot along a printing track. The robot includes a print head mounted at the front end. Further, the printing system has: a rotation angle sensor that detects the actual position of the print head; and a piezoelectric actuator that is disposed between the print head and corrects the position of the print head based on the actual position of the print head. Thus, printing without stripes (gaps) is achieved by correcting the position of the print head based on the actual position of the print head.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-202781.

[0006] In a printing system such as that of Patent Document 1, generally, ink stored in an ink storage tank is supplied to the print head via a flow path such as a tube. Therefore, depending on the position of the print head, particularly the height of the print head, the amount of ink supplied from the ink storage tank to the print head decreases, and a decrease in printing quality due to ink shortage may occur. Summary of the Invention

[0007] The printing system of the present invention includes: a robot having a robotic arm that supports and moves a print head that ejects ink; and an ink storage unit that stores the ink supplied to the print head, wherein the ink storage unit is located above the print head's movement range in the vertical direction.

[0008] The printing method of the present invention is a printing method for performing a printing operation on an object using a robot having a robotic arm that supports and moves a print head that ejects ink, wherein the printing operation is performed by moving the print head to a position below the ink storage unit that stores the ink supplied to the print head in the vertical direction. Brief Description of the Drawings

[0009] Figure 1 is an overall view of the printing system according to the first embodiment.

[0010] Figure 2 Shows Figure 1 a top view of a moving table and a print head included in the shown robot.

[0011] Figure 3 It is an exploded perspective view of the print head.

[0012] Figure 4 It is a perspective sectional view of the print head.

[0013] Figure 5 It is a sectional view showing the structure of the ink supply section.

[0014] Figure 6 It is a flow chart of the printing operation.

[0015] Figure 7 It is a side view showing a part of the printing system according to the second embodiment.

[0016] Figure 8 It is an overall view of the printing system according to the third embodiment.

[0017] Figure 9 It is an overall view of the printing system according to the fourth embodiment.

[0018] Figure 10 It is a view showing a state where the print head is located on the lower side in the vertical direction compared to the ink storage tank.

[0019] Figure 11 It is a view showing a state where the print head is located on the lower side in the vertical direction compared to the ink storage tank.

[0020] Figure 12 It is a view showing a state where the print head is located on the upper side in the vertical direction compared to the ink storage tank.

[0021] Figure 13 It is a view showing a state where the print head is located on the upper side in the vertical direction compared to the ink storage tank.

[0022] Figure 14 It is a flow chart of the printing operation.

[0023] Figure 15 It is an overall view of the printing system according to the fifth embodiment.

[0024] Figure 16 It is a view showing a state where the print head is located on the lower side in the vertical direction compared to the ink storage tank.

[0025] Figure 17 It is a view showing a state where the print head is located on the upper side in the vertical direction compared to the ink storage tank.

[0026] Figure 18 It is a view showing the front end portion of the robot included in the printing system according to the sixth embodiment.

[0027] Figure 19It is an overall view of the printing system according to the seventh embodiment.

[0028] Figure 20 It is a flowchart of the ink supply method.

[0029] Symbol Explanation

[0030] 1. Printing system; 2. Robot; 3. Robot main body; 30. Fixed part; 31. Base; 32. Robot arm; 321. Arm; 322. Arm; 323. Arm; 324. Arm; 325. Arm; 326. Arm; 4. Moving worktable; 40. Base; 400. Piezoelectric actuator; 41. First worktable; 42. Second worktable; 45. First worktable drive unit; 46. Second worktable drive unit; 5. Print head; 51. Nozzle plate; 52. Pressure chamber forming substrate; 53. Vibration plate; 54. Sealing part; 561. Liquid storage tank; 562. Ink chamber; 563. Nozzle; 564. Piezoelectric element; 6. Inertial sensor; 7. Stand; 70. Ink ejection amount detector; 71. Camera; 72. Image processing unit; 8. Control device; 9. Ink supply unit; 91. Ink storage tank; 92. Pipe; 93. On-off valve; 94. Pump; 941. Vacuum pump; 942. Pressure pump; 95. Pump control device; 96. Regulator; 97. Valve; A. First direction; B. Second direction; D1. Lower end; D2. Upper end; E. Moving range; F1. Liquid level; F2. Liquid level; I. Ink; J1. Joint; J2. Joint; J3. Joint; J4. Joint; J5. Joint; J6. Joint; Q. Printing track; S1. Printing condition determination process; S2. Printing process; W. Object. Detailed Embodiments

[0031] Hereinafter, the printing system and the printing method of the present invention will be described in detail based on the embodiments shown in the drawings.

[0032] Figure 1 It is an overall view of the printing system according to the first embodiment. Figure 2 It shows Figure 1 A top view of the moving worktable and the print head provided in the shown robot. Figure 3 It is an exploded perspective view of the print head. Figure 4 It is a three-dimensional cross-sectional view of the print head. Figure 5 It is a cross-sectional view showing the structure of the ink supply unit. Figure 6 It is a flowchart of the printing operation. In addition, Figure 1 , Figure 3 , Figure 4 and Figure 5 The vertical direction in is along the vertical direction. Hereinafter, for the sake of convenience of explanation, the upper side in this figure is also referred to as "upper" or "upper side in the vertical direction", and the lower side is also referred to as "lower" or "lower side in the vertical direction".

[0033] Figure 1 The printing system 1 shown has: a robot 2 that performs printing on an object W; a control device 8 that controls the driving of the robot 2; and an ink supply unit 9 that supplies ink I to the robot 2. Further, the robot 2 has: a robot body 3 having a robotic arm 32; a moving table 4 disposed at the front end of the robotic arm 32; a print head 5 disposed on the moving table 4; and an inertial sensor 6 as a vibration meter disposed on the print head 5. Further, the ink supply unit 9 has: an ink storage tank 91 which is an ink storage unit for storing the ink I; a pipe 92 which is a pipe connecting the ink storage tank 91 and the print head 5; and an on-off valve 93 located between the pipe 92 and the print head 5. In such a printing system 1, while moving the print head 5 along a printing track Q using the robotic arm 32, the ink I is ejected from the print head 5 at a predetermined timing, thereby performing a printing operation on the object W.

[0034] In addition, in the printing system 1 of the present embodiment, the object W is fixed and only the print head 5 is moved, thereby relatively moving the object W and the print head 5. However, it is not limited thereto, and the object W and the print head 5 may be relatively moved by moving the print head 5 and the object W together.

[0035] Robot body 3

[0036] As Figure 1 shown, the robot body 3 is a six-axis vertical articulated robot having six drive axes, and has a base 31 fixed to a mounting table, a floor, etc. and a robotic arm 32 rotatably connected to the base 31. Further, the robotic arm 32 is structured such that six arms 321, 322, 323, 324, 325, 326 are sequentially rotatably connected from the base 31 side, and includes six joints J1, J2, J3, J4, J5, J6. Specifically, the arm 321 is connected to the base 31 via the joint J1 so as to be rotatable, the arm 322 is connected to the arm 321 via the joint J2 so as to be rotatable, the arm 323 is connected to the arm 322 via the joint J3 so as to be rotatable, the arm 324 is connected to the arm 323 via the joint J4 so as to be rotatable, the arm 325 is connected to the arm 324 via the joint J5 so as to be rotatable, and the arm 326 is connected to the arm 325 via the joint J6 so as to be rotatable.

[0037] In addition, among the joints J1 to J6, the joints J2, J3, and J5 are bending joints, and the joints J1, J4, and J6 are torsion joints. In addition, a driving mechanism is provided on each of the joints J1, J2, J3, J4, J5, and J6, and the driving mechanism includes a motor, a reducer that reduces the rotation of the motor to increase the torque and output it, and an encoder that detects the rotation amount of the joint. Furthermore, by moving each of the joints J1, J2, J3, J4, J5, and J6 independently, the print head 5 disposed at the front end of the robot arm 32 can be moved in a desired direction at a desired posture and speed.

[0038] However, the structure of the robot body 3 is not particularly limited. For example, the number of arms provided by the robot arm 32 is not limited to six. In addition, the robot body 3 may also be a dual-arm robot, a horizontal multi-joint robot (scara robot), etc. In addition, the robot body 3 may not be fixed to a mounting table, a floor, etc., but may be able to walk on its own.

[0039] Mobile workbench 4

[0040] like Figure 1 As shown, the movable workbench 4 is arranged at the front end of the robot arm 32, that is, the arm 326. The movable workbench 4 is used for position correction of the printing head 5. Figure 2 As shown, the movable stage 4 includes: a base 40 supported by an arm 326; a first stage 41 linearly moving in a first direction A relative to the base 40; and a second stage 42 linearly moving in a second direction B orthogonal to the first direction A relative to the first stage 41. In addition, a printing head 5 is arranged on the second stage 42.

[0041] In addition, the movable table 4 has: a first table driving unit 45, which moves the first table 41 along the first direction A relative to the base 40; and a second table driving unit 46, which moves the second table 42 along the second direction B relative to the first table 41. The first and second table driving units 45 and 46 are respectively equipped with piezoelectric actuators 400 driven by the expansion and contraction of the piezoelectric element caused by energization, and the first and second tables 41 and 42 are moved by transmitting the vibration of the piezoelectric actuator 400 to them. In this way, by using the piezoelectric actuator 400, the movement amount and movement speed of the first and second tables 41 and 42 can be finely and accurately controlled, and the switching of the movement direction also becomes sensitive. In addition, the miniaturization and lightness of the movable table 4 can also be achieved. Therefore, the position correction of the printing head 5 can be performed with higher precision.

[0042] However, the structure of the moving stage 4 is not particularly limited. For example, the first and second stage driving units 45 and 46 may also be configured to use a driving source other than the piezoelectric actuator 400, such as a motor that rotates by being energized. Additionally, the moving stage 4 may also have a third stage that linearly moves in a direction orthogonal to the first direction A and the second direction B, and a fourth stage that rotationally moves around an axis orthogonal to the first direction A and the second direction B. Alternatively, the moving stage 4 may be omitted. In this case, the position correction of the print head 5 may be performed only by the robotic arm 32.

[0043] print head 5

[0044] As Figure 2 shown, the print head 5 is disposed on the second stage 42. The print head 5 is not particularly limited. In the present embodiment, it is an inkjet head of a piezoelectric driving type. As Figure 3 and Figure 4 shown, such a print head 5 has a structure in which a nozzle plate 51, a pressure chamber forming substrate 52, a vibrating plate 53, and a sealing portion 54 are laminated, and has a liquid storage tank 561 as a common ink chamber, a plurality of ink chambers 562 branched from the liquid storage tank 561, and a plurality of nozzles 563 formed in each ink chamber 562. The plurality of ink chambers 562 are arranged in a line in a direction orthogonal to the printing track Q. Additionally, piezoelectric elements 564 are respectively disposed on the vibrating plate 53 that forms the top of each ink chamber 562. In such a structure of the print head 5, ink I is supplied from the ink storage tank 91 to the liquid storage tank 561, and then from the liquid storage tank 561 to each ink chamber 562. And for each ink chamber 562, the piezoelectric element 564 is vibrated by being energized, whereby a predetermined amount of ink I is ejected from the nozzle 563. Therefore, while moving the print head 5 along the printing track Q, ink I is ejected from each nozzle 563 at a predetermined timing and made to land on the object W, thereby printing a predetermined printed image on the object W.

[0045] However, the structure of the print head 5 is not particularly limited. For example, it may be configured such that multiple print heads 5 are arranged along the printing track Q to enable multicolor printing. Specifically, for example, the print head 5 may be as follows: By arranging multiple print heads that eject black ink I, print heads that eject cyan ink I, print heads that eject magenta ink I, and print heads that eject yellow ink I along the printing track Q, full-color printing can be enabled. Additionally, the structure of the print head 5 is not limited to the above-described piezoelectric driving type inkjet head. For example, it may also be an inkjet head of a thermal type that utilizes the film boiling phenomenon of ink I, a bubble ejection type that generates bubbles in ink I by applying heat and ejects the ink I, an electrostatic actuator type that displaces and vibrates the vibrating plate by electrostatic force and ejects the ink I, etc.

[0046] Inertial Sensor 6

[0047] like Figure 1 and Figure 2 As shown, the inertial sensor 6 is disposed on the printing head 5 to detect vibration of the printing head 5. In addition, the "vibration" means an unnecessary displacement of the printing head 5 other than the displacement along the printing track Q. The inertial sensor 6 is not particularly limited as long as it can detect vibration. For example, a three-axis acceleration sensor that detects acceleration in three mutually orthogonal axial directions can be used.

[0048] Control device 8

[0049] like Figure 1 As shown, the control device 8 is electrically connected to the robot 2 to control the driving of the robot 2. Specifically, the control device 8 controls the driving of the robot body 3, the movable table 4, the printing head 5, and the inertial sensor 6 independently or in conjunction with each other. Such a control device 8 is composed of, for example, a computer, and has a processor (CPU) for processing information, a memory connected to the processor in a communicable manner, and an external interface for connecting to an external device. Various programs that can be executed by the processor are stored in the memory, and the processor can read and execute the programs stored in the memory.

[0050] Ink supply unit 9

[0051] like Figure 1 As shown, as described above, the ink supply unit 9 includes: an ink storage tank 91, which is an ink storage unit for storing ink I; a tube 92, which is a pipeline connecting the ink storage tank 91 and the print head 5; and an opening and closing valve 93, which is located between the tube 92 and the print head 5.

[0052] The ink tank 91 is arranged separately from the robot 2. In other words, the ink tank 91 is arranged separately from the robot 2. By setting such a structure, the arrangement freedom of the ink tank 91 increases, and it is easy to construct the printing system 1. The ink tank 91 stores the ink I used in the printing operation.

[0053] In addition, the ink storage tank 91 is connected to the liquid storage tank 561 of the print head 5 via the tube 92. Therefore, the ink I in the ink storage tank 91 flows in the tube 92 and is supplied to the liquid storage tank 561 of the print head 5. With such a structure, the freedom of arrangement of the ink storage tank 91 increases, and the printing system 1 is easily constructed.

[0054] Here, the tube 92 is flexible and is arranged above the robot 2 in the vertical direction. In the illustrated example, the tube 92 is led out from the ink storage tank 91 upward in the vertical direction, extends along the top to the head of the robot 2, and hangs downward from here in the vertical direction, thereby connecting to the liquid storage tank 561 of the print head 5. By adopting such a structure, it is difficult for the robot 2 to hook on the tube 92 during the printing operation. Therefore, the robot 2 can move smoothly, and in addition, the detachment and breakage of the tube 92 caused by contact with the robot 2 can be suppressed. Therefore, the printing operation can be performed with higher precision.

[0055] In addition, in the printing system 1, as Figure 5 shown, the ink I in the ink storage tank 91 is supplied to the liquid storage tank 561 of the print head 5 by using the principle of siphon, that is, the water head difference. By using the siphon principle, the ink I in the ink storage tank 91 can be supplied to the print head 5 without using power such as a pump. Therefore, the power consumption of the printing system 1 can be reduced, and the simplification of the printing system 1 can also be achieved.

[0056] Here, in order to stably and continuously supply the ink I in the ink storage tank 91 to the print head 5 by using the siphon principle, in the printing system 1, during the printing operation, the print head 5 is moved in such a way that the liquid level F1 of the ink I in the ink storage tank 91 is always located above the liquid level F2 of the ink I in the liquid storage tank 561 in the vertical direction. That is, in the printing system 1, when the area where the print head 5 moves during the printing operation is set as the "moving range E", the ink storage tank 91 is located above the moving range E of the print head 5 in the vertical direction. Thereby, during the printing operation, the supply of the ink I to the liquid storage tank 561 is stably and continuously carried out. Therefore, the ink shortage of the print head 5 can be suppressed. In addition, during the printing operation, the supply pressure of the ink I supplied to the liquid storage tank 561 is stable, so a predetermined amount of the ink I can be stably ejected from each nozzle 563. Therefore, a high printing quality can be achieved.

[0057] Here, as described above, the so-called arrangement of the ink storage tank 91 above the moving range E of the print head 5 in the vertical direction means that the liquid level F1 of the ink I in the ink storage tank 91 is located above the liquid level F2 of the ink I in the liquid storage tank 561 in the vertical direction. However, it is difficult to detect the liquid levels F1 and F2, and additional measuring instruments are required for the detection of the liquid levels F1 and F2. Therefore, it may lead to technical difficulties and the complication of the device. Therefore, in the printing system 1, based on the lower end D1 of the ink storage tank 91 and the upper end D2 of the print head 5, during the printing operation, the print head 5 is moved in such a way that the lower end D1 of the ink storage tank 91 is always located above the upper end D2 of the print head 5. According to such a method, it is possible to simply arrange the ink storage tank 91 above the moving range E of the print head 5 in the vertical direction.

[0058] In addition, as the meaning of the movement range E, it may be set as the area where the print head 5 moves during the printing operation as in this embodiment, but it may also be set as an area wider than that with a margin. In this case, for example, the movement range E may be set as the movable area of the robot arm 32. If the movement range E is set as the movable area of the robot arm 32, regardless of the movement of the print head 5 during the printing operation, the lower end D1 of the ink storage tank 91 is always located on the upper side in the vertical direction compared to the upper end D2 of the print head 5. Therefore, it is difficult to impose restrictions on the movement of the print head 5 during the printing operation, and the printing operation can be smoothly performed.

[0059] In addition, an on-off valve 93 is disposed between the pipe 92 and the print head 5. The on-off valve 93 can be switched to an open state that allows the supply of the ink I from the ink storage tank 91 to the print head 5 and a closed state that restricts the supply of the ink I from the ink storage tank 91 to the print head 5. By setting the on-off valve 93 to the closed state, for example, maintenance such as cleaning and replacement of the print head 5 can be easily performed. In addition, by setting it to the closed state when the printing operation is not performed, leakage of the ink I from the nozzle 563 can also be suppressed. In particular, by disposing the on-off valve 93 between the pipe 92 and the print head 5, the on-off valve 93 can be disposed near the print head 5. Therefore, the amount of the ink I remaining on the downstream side (print head 5 side) from the on-off valve 93 can be further reduced. For example, the amount of the ink I discarded during the maintenance of the print head 5 can be reduced.

[0060] In addition, the on-off valve 93 can be manually operated by the user or electrically operated by the control device 8. In addition, the arrangement of the on-off valve 93 is not particularly limited. For example, it may be in the middle of the pipe 92 or between the ink storage tank 91 and the pipe 92. In addition, the on-off valve 93 may be omitted.

[0061] Above, the structure of the printing system 1 has been described. Next, a printing method using the printing system 1 will be described. As Figure 6 shown, the printing method includes a printing condition determination step S1 and a printing step S2.

[0062] Printing condition determination step S1

[0063] In the printing condition determination process S1, first, printing conditions such as the printing trajectory Q and the ejection timing of the ink I ejected from each nozzle 563 are determined based on the shape of the object W and the sample image printed on the object W. That is, in order to print the sample image on the object W, it is determined how to move the print head 5 relative to the object W and further at what timing it is better to eject the ink I. Further, it is confirmed whether the upper end D2 of the print head 5 is located on the lower side in the vertical direction compared to the lower end D1 of the ink storage tank 91 when the print head 5 is moved along the printing trajectory Q. If necessary, the position of the printing trajectory Q or the ink storage tank 91 is changed. In addition, regarding the shape of the object W, it is preferable to use, for example, the CAD data of the object W. Thereby, the shape of the object W can be obtained with high precision, and the printing trajectory Q can be further optimized.

[0064] Printing process S2

[0065] In the printing process S2, the official printing on the object W is performed based on the printing conditions determined in the printing condition determination process S1. That is, the control device 8 moves the print head 5 relative to the object W along the printing trajectory Q while ejecting the ink I from each nozzle 563 at a predetermined timing. Thereby, the printed image is printed on the object W. In addition, the control device 8 detects the vibration of the print head 5 based on the output of the inertial sensor 6 during the printing operation, and controls the drive of the moving table 4 to eliminate the detected vibration. Specifically, the drive of the moving table 4 is controlled so that a vibration having a phase opposite to the detected vibration is applied to the print head 5. Thereby, the vibration of the print head 5 during the printing operation is suppressed, and higher-quality printing can be performed.

[0066] As described above, the printing system 1 has been described. As described above, such a printing system 1 includes: a robot 2 having a robotic arm 32 that supports and moves the print head 5 that ejects the ink I; and an ink storage tank 91 that is an ink storage unit that stores the ink I supplied to the print head 5. Further, the ink storage tank 91 is located on the upper side in the vertical direction compared to the movement range E of the print head 5. According to such a structure, during the printing operation, due to the principle of siphon, the supply of the ink I to the print head 5 continuously and stably, and ink shortage is suppressed. In addition, the supply pressure of the ink I supplied to the print head 5 is stable. Therefore, a predetermined amount of the ink I can be stably ejected from the print head 5, and higher printing quality can be achieved.

[0067] In addition, as described above, the ink storage tank 91 is separately arranged from the robot 2. By adopting such a structure, the degree of freedom in arranging the ink storage tank 91 increases, and it is easy to construct the printing system 1.

[0068] In addition, as described above, the printing system 1 has a tube 92 which is a pipeline connecting the ink storage tank 91 and the print head 5. With such a structure, the degree of freedom in arranging the ink storage tank 91 increases, and it is easy to construct the printing system 1.

[0069] In addition, as described above, the tube 92 connects the ink storage tank 91 and the print head 5 via the upper side in the vertical direction of the robot 2. With such a structure, it is difficult for the robot 2 to catch on the tube 92 during the printing operation. Therefore, the robot 2 can move smoothly, and in addition, it is possible to suppress the detachment and breakage of the tube 92 due to contact with the robot 2. Therefore, the printing operation can be performed with higher precision.

[0070] In addition, as described above, the printing system 1 has an on-off valve 93 which switches between a state allowing the supply of the ink I from the ink storage tank 91 to the print head 5 and a state restricting the supply of the ink I from the ink storage tank 91 to the print head 5. Therefore, by setting the on-off valve 93 to the closed state, for example, it is possible to easily perform maintenance such as cleaning and replacement of the print head 5. In addition, it is also possible to suppress the leakage of the ink I from the nozzle 563 when the printing operation is not performed.

[0071] In addition, as described above, the on-off valve 93 is arranged between the print head 5 and the tube 92. According to such a structure, the on-off valve 93 can be arranged near the print head 5. Therefore, it is possible to further reduce the amount of the ink I remaining on the downstream side (the print head 5 side) of the on-off valve 93. For example, it is possible to reduce the amount of the ink I discarded during the maintenance of the print head 5.

[0072] In addition, as described above, the printing method using the printing system 1 is a printing method that uses the robot 2 to perform a printing operation on the object W, and the robot 2 has a robotic arm 32 that supports and moves the print head 5 that ejects the ink I. This printing method moves the print head 5 to a position below the ink storage tank 91, which is an ink storage section for storing the ink I supplied to the print head 5, in the vertical direction to perform the printing operation. According to such a method, during the printing operation, due to the siphon principle, the supply of the ink I to the print head 5 continues stably, and the supply pressure of the ink I supplied to the print head 5 is stable. Therefore, it is possible to stably eject a predetermined amount of the ink I from the print head 5, and a high printing quality can be achieved.

[0073] Second Embodiment

[0074] Figure 7 It is a side view showing a part of the printing system according to the second embodiment.

[0075] This embodiment is the same as the above-described first embodiment except for the structure of the ink supply unit 9. In addition, in the following description, regarding this embodiment, the differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted. In the drawings of this embodiment, the same reference numerals are given to the same structures as those in the above-described embodiment.

[0076] As Figure 7 shown, in the printing system 1 of this embodiment, the ink supply unit 9 is disposed on the robot 2. Specifically, the print head 5 and the ink storage tank 91 are respectively fixed to the moving worktable 4 via the fixing member 30. Such a structure can also be said that the printing system 1 has a fixing member 30 that fixes the print head 5 to the robotic arm 32, and the ink storage tank 91 is disposed on the fixing member 30. Thus, by fixing the ink storage tank 91 to the robot 2, the distance between the ink storage tank 91 and the print head 5, that is, the length of the tube 92, can be shortened. Therefore, the loss of the supply pressure of the ink I supplied to the liquid storage tank 561 is reduced, and a predetermined amount of the ink I can be ejected more stably from each nozzle 563.

[0077] In addition, in this embodiment, the ink storage tank 91 and the print head 5 are connected via the tube 92, but it is not limited thereto, and the tube 92 may be omitted and directly connected. Thereby, the structure of the ink supply unit 9 can be further simplified. In addition, since the detachment, breakage, etc. of the tube 92 do not occur, the ink I can be supplied from the ink storage tank 91 to the print head 5 more reliably.

[0078] In addition, the ink storage tank 91 is disposed on the side opposite to the ejection direction of the ink I with respect to the print head 5. In this embodiment, as Figure 7 shown, it is set that the ink I is ejected downward during the printing operation. Therefore, during the printing operation, the ink storage tank 91 is always located above the print head 5 in the vertical direction. Therefore, during the printing operation, due to the siphon principle, the supply of the ink I to the liquid storage tank 561 continues stably, and the supply pressure of the ink I supplied to the liquid storage tank 561 is stable. Therefore, a predetermined amount of the ink I can be ejected stably from each nozzle 563. As a result, a high printing quality can be exhibited.

[0079] As described above, the printing system 1 of this embodiment has a fixing member 30 that fixes the print head 5 to the robotic arm 32, and the ink storage tank 91 is disposed on the fixing member 30. According to such a structure, the distance between the ink storage tank 91 and the print head 5, that is, the length of the tube 92, can be shortened. Therefore, the loss of the supply pressure of the ink I supplied to the liquid storage tank 561 is reduced, and a predetermined amount of the ink I can be ejected more stably from each nozzle 563.

[0080] In addition, as described above, the ink storage tank 91 is arranged on the side opposite to the ejection direction of the ink I with respect to the print head 5. Therefore, by performing the printing operation in such a manner that the ink I is ejected downward in the vertical direction, the ink storage tank 91 is always located above the print head 5 in the vertical direction. Thus, during the printing operation, due to the siphon principle, the supply of the ink I to the liquid storage tank 561 continues stably, and the supply pressure of the ink I supplied to the liquid storage tank 561 is stable. Therefore, a predetermined amount of the ink I can be stably ejected from each nozzle 563. As a result, a high printing quality can be achieved.

[0081] With such a second embodiment, the same effects as those of the above-described first embodiment can also be achieved. In addition, in the present embodiment, the ink storage tank 91 is fixed to the arm 326 via the moving table 4, but the arrangement of the ink storage tank 91 is not particularly limited, and it may be fixed to any one of, for example, the arms 321, 322, 323, 324, and 325.

[0082] Third Embodiment

[0083] Figure 8 is an overall view of the printing system according to the third embodiment.

[0084] This embodiment is the same as the above-described first embodiment except that the robot 2 is suspended upside down. In addition, in the following description, regarding this embodiment, the differences from the above-described embodiments will be mainly described, and the description of the same matters will be omitted. In the drawings of the present embodiment, the same reference numerals are given to the same structures as those of the above-described embodiments.

[0085] As Figure 8 shown, the printing system 1 of the present embodiment has a gantry 7 that suspends and supports the robot 2 upside down. That is, the robot 2 is fixed to the gantry 7 in a posture opposite to that of the above-described first embodiment. In addition, the ink storage tank 91 is arranged on the gantry 7. According to such a structure, compared with the above-described first embodiment, a larger space can be ensured on the ground side, and thus there are advantages such as being able to print on a larger object W, for example.

[0086] As described above, the printing system 1 of the present embodiment has a gantry 7 that suspends and supports the robot 2. According to such a structure, compared with the above-described first embodiment, a larger space can be ensured on the ground side, and thus there are advantages such as being able to print on a larger object W, for example.

[0087] With such a third embodiment, the same effects as those of the above-described first embodiment can also be achieved.

[0088] Fourth Embodiment

[0089] Figure 9 It is an overall view of the printing system according to the fourth embodiment. Figure 10 and Figure 11 are diagrams respectively showing the state where the print head is located on the lower side in the vertical direction compared to the ink storage tank. Figure 12 and Figure 13 are diagrams respectively showing the state where the print head is located on the upper side in the vertical direction compared to the ink storage tank. Figure 14 It is a flowchart of the printing operation.

[0090] This embodiment is the same as the above-described first embodiment except for the structure of the ink supply unit 9. In addition, in the following description, regarding this embodiment, the description will focus on the differences from the above-described embodiments, and the description of the same matters will be omitted. In addition, in the diagrams of this embodiment, the same reference numerals are assigned to the same structures as those in the above-described embodiments.

[0091] The ink supply unit 9 includes a pump 94 as a supply pressure control unit disposed in the middle of the pipe 92 and a pump control device 95 that controls the driving of the pump 94.

[0092] The pump 94 is disposed in the middle of the pipe 92. The pump 94 is a vacuum pump 941. By decompressing the inside of the pipe 92, the ink I in the ink storage tank 91 can be introduced into the pipe 92, and the introduced ink I can be forcibly sent to the print head 5.

[0093] The pump control device 95 is electrically connected to the vacuum pump 941 and the control device 8. And, based on the position of the print head 5 sent from the control device 8, the driving of the vacuum pump 941 is controlled. Such a pump control device 95 is constituted by, for example, a computer, and has a processor (CPU) that processes information, a memory connected to the processor in a communicable manner, and an external interface connected to an external device. Various programs that can be executed by the processor are stored in the memory, and the processor can read and execute the programs stored in the memory, etc.

[0094] Above, the structure of the printing system has been described. Next, a method for supplying the ink I from the ink storage tank 91 to the print head 5 will be described. In the printing system 1, by controlling the driving of the vacuum pump 941, the supply pressure of the ink I supplied from the ink storage tank 91 to the print head 5 is changed according to the position of the print head 5 relative to the ink storage tank 91. More specifically, the supply pressure of the ink I when the print head 5 is located on the upper side in the vertical direction of the ink storage tank 91 is greater than the supply pressure of the ink I when the print head 5 is located on the lower side in the vertical direction of the ink storage tank 91. Thereby, regardless of the position of the print head 5, the ink I can be stably supplied from the ink storage tank 91 to the print head 5. Therefore, the shortage of ink in the print head 5 during the printing operation is suppressed, and high-quality printing can be performed.

[0095] In the present embodiment, as Figure 10 shown, when the print head 5 is located below the ink storage tank 91 in the vertical direction, the pump control device 95 turns off the decompression pump 941. That is, the decompression pump 941 is not driven. In this case, as Figure 11 shown, since the liquid level F2 of the ink in the liquid storage tank 561 of the print head 5 is located below the liquid level F1 of the ink I in the ink storage tank 91 in the vertical direction, the ink I in the ink storage tank 91 can be supplied to the liquid storage tank 561 of the print head 5 by using the head difference between the two, that is, the principle of siphon. Therefore, even if the decompression pump 941 is turned off, the ink I can be stably supplied to the print head 5.

[0096] Here, the so-called "the print head 5 is located below the ink storage tank 91 in the vertical direction" means in detail that the liquid level F2 of the ink in the liquid storage tank 561 of the print head 5 is located below the liquid level F1 of the ink I in the ink storage tank 91 in the vertical direction, but it is difficult to detect the liquid levels F1 and F2, and in addition, separate measuring instruments are required for the detection of the liquid levels F1 and F2. Therefore, it may lead to technical difficulties and complication of the device.

[0097] Therefore, in the printing system 1, based on the upper end D2 of the print head 5 and the lower end D1 of the ink storage tank 91, the situation where the upper end D2 of the print head 5 is located below the lower end D1 of the ink storage tank 91 in the vertical direction is defined as the state of "the print head 5 is located below the ink storage tank 91 in the vertical direction", and conversely, the situation where the upper end D2 of the print head 5 and the lower end D1 of the ink storage tank 91 are at the same height, or the upper end D2 of the print head 5 is located above the lower end D1 of the ink storage tank 91 in the vertical direction is defined as the state of "the print head 5 is located above the ink storage tank 91 in the vertical direction". Thus, it is possible to easily determine whether the print head 5 is located below or above the ink storage tank 91 in the vertical direction.

[0098] On the other hand, as Figure 12 shown, when the print head 5 is located above the ink storage tank 91 in the vertical direction, the pump control device 95 turns on the decompression pump 941. That is, the decompression pump 941 is driven. In this case, as Figure 13As shown, the liquid level F2 of the ink is located on the upper side in the vertical direction compared to the liquid level F1 of the ink I in the ink storage tank 91. Therefore, the siphon principle cannot be used to supply the ink I. Thus, the pump control device 95 turns on the decompression pump 941 and forcibly supplies the ink I in the ink storage tank 91 to the print head 5. According to this method, compared with the case where the print head 5 is located on the lower side in the vertical direction compared to the ink storage tank 91, the supply pressure of the ink I supplied to the print head 5 increases. Even when the print head 5 is in a state where it is located on the upper side in the vertical direction compared to the ink storage tank 91, the ink I can be stably supplied to the print head 5.

[0099] As described above, according to the printing system, when the print head 5 is located on the lower side in the vertical direction compared to the ink storage tank 91 (hereinafter, also referred to as the "lower side state"), the decompression pump 941 is turned off, and the ink I in the ink storage tank 91 is supplied to the liquid storage tank 561 of the print head 5 using the siphon principle. On the other hand, when the print head 5 is located on the upper side in the vertical direction compared to the ink storage tank 91 (hereinafter, also referred to as the "upper side state"), the decompression pump 941 is turned on to make the supply pressure of the ink I higher than that in the lower side state, and the ink I in the ink storage tank 91 is forcibly supplied to the print head 5. In this way, according to the method of changing the supply pressure of the ink I based on the position of the print head 5 relative to the ink storage tank 91, regardless of the position of the print head 5 relative to the ink storage tank 91, the ink I in the ink storage tank 91 can be stably supplied to the print head 5, and the shortage of ink in the print head 5 during the printing operation can be suppressed. Therefore, a predetermined amount of ink I can be stably ejected from the print head 5, and high printing quality can be achieved.

[0100] In addition, in the present embodiment, since the supply pressure of the ink I is changed by controlling the drive of the pump 94, the supply pressure of the ink I can be changed by simple control. In particular, in the present embodiment, since it is the on / off control of the decompression pump 941, the control for changing the supply pressure of the ink I becomes simpler. Also, when the print head 5 is located on the lower side in the vertical direction compared to the ink storage tank 91, by turning off the decompression pump 941, the power consumption of the printing system 1 can also be reduced.

[0101] The method of supplying Ink I to the print head 5 has been described above, but the method of supplying Ink I is not particularly limited. For example, the vacuum pump 941 may be turned on even in the lower state. In this case, it is only necessary to make the output of the vacuum pump 941 in the lower state smaller than the output of the vacuum pump 941 in the upper state, and make the supply pressure of Ink I in the lower state lower than the supply pressure of Ink I in the upper state. In the upper state, the output of the vacuum pump 941 may also be changed according to the height difference between the print head 5 and the ink storage tank 91. Specifically, it may be that the greater the height difference between the print head 5 and the ink storage tank 91, that is, the higher the position of the print head 5, the greater the output of the vacuum pump 941, and the supply pressure of Ink I is increased. Thus, Ink I in the ink storage tank 91 can be supplied to the print head 5 more stably.

[0102] In addition, during the printing operation (when the print head 5 is moving along the printing track), the pump control device 95 detects the relative positional relationship between the print head 5 and the ink storage tank 91 based on the position of the print head 5 periodically received from the control device 8, and controls the driving of the vacuum pump 941 based on the detection result. That is, if the print head 5 is in the lower state, the vacuum pump 941 is turned off, and if the print head 5 is in the upper state, the vacuum pump 941 is turned on. Thus, during the printing operation, Ink I is stably supplied from the ink storage tank 91 to the print head 5, and a high-quality printed pattern can be printed.

[0103] In addition, the printed pattern is not particularly limited, including a pattern of full coating, but preferably a pattern. In the pattern, for example, in addition to the pattern, it also includes pictures, photos, characters, marks, etc., which means a pattern including patterns other than the pattern of full coating. In this way, by printing a pattern as the printed pattern, the reduction in printing quality caused by insufficient ink is significantly shown, so the effect of the printing system 1 can be enjoyed more significantly.

[0104] The printing system 1 has been described above. As described above, the printing method using such a printing system 1 is as follows: A robot 2 equipped with a print head 5 that ejects Ink I supplied from an ink storage tank 91 as an ink storage unit moves the print head 5 relative to an object W and ejects Ink I from the print head 5, thereby printing a printed pattern on the object W, and changing the supply pressure of Ink I supplied from the ink storage tank 91 to the print head 5 according to the position of the print head 5 relative to the ink storage tank 91. According to such a method, regardless of the position of the print head 5 relative to the ink storage tank 91, Ink I in the ink storage tank 91 can be stably supplied to the print head 5, so the shortage of ink in the print head 5 during the printing operation is suppressed. Therefore, a predetermined amount of Ink I can be stably ejected from the print head 5, and a high printing quality can be achieved.

[0105] In addition, as described above, in the printing method using the printing system 1, the supply pressure of the ink I when the print head 5 is located below the ink storage tank 91 in the vertical direction is higher than the supply pressure of the ink I when the print head 5 is located above the ink storage tank 91 in the vertical direction. According to such a method, even when the print head 5 is in a state of being located above the ink storage tank 91 in the vertical direction, the ink I can be stably supplied to the print head 5.

[0106] In addition, as described above, in the printing method using the printing system 1, the printed pattern is a pattern. Thus, by printing a pattern as the printed pattern, the reduction in printing quality caused by insufficient ink is significantly exhibited, and therefore the effect of the printing system 1 can be more significantly enjoyed.

[0107] In addition, as described above, in the printing method using the printing system 1, the ink I in the ink storage tank 91 is supplied to the print head 5 by using a pump 94, and the driving of the pump 94 is controlled to change the supply pressure of the ink I. According to such a method, the supply pressure of the ink I can be changed by simple control.

[0108] In addition, as described above, in the printing method using the printing system 1, the ink storage tank 91 and the print head 5 are connected by a tube 92 as a pipeline, and the pump 94 is a decompression pump 941 that decompresses the inside of the tube 92. Thus, by driving the decompression pump 941, the ink I in the ink storage tank 91 can be forcibly supplied to the print head 5. In addition, by controlling the on / off of the decompression pump 941 or the output at the time of turning on, the supply pressure of the ink I can be simply changed.

[0109] In addition, as described above, the printing system 1 includes: an ink storage tank 91, which is an ink storage unit for storing the ink I; a robot 2, which has a print head 5 that ejects the ink I supplied from the ink storage tank 91; and a pump 94, which is a supply pressure control unit that changes the supply pressure of the ink I supplied from the ink storage tank 91 to the print head 5 according to the position of the print head 5 relative to the ink storage tank 91. According to such a structure, regardless of the position of the print head 5 relative to the ink storage tank 91, the ink I in the ink storage tank 91 can be stably supplied to the print head 5, so that the shortage of ink in the print head 5 during the printing operation is suppressed. Therefore, a predetermined amount of the ink I can be stably ejected from the print head 5, and a high printing quality can be achieved.

[0110] Fifth Embodiment

[0111] Figure 15 is an overall view of the printing system according to the fifth embodiment. Figure 16 is a view showing a state where the print head is located below the ink storage tank in the vertical direction. Figure 17This is a diagram showing the state where the print head is located above the ink storage tank in the vertical direction.

[0112] The printing system of this embodiment is the same as the printing system of the fourth embodiment described above, except for the structure of the ink supply unit 9. In addition, in the following description, regarding this embodiment, the differences from the above embodiments will be mainly described, and the description of the same matters will be omitted. Also, in the figures of this embodiment, the same reference numerals are used for the same structures as those in the above embodiments.

[0113] As Figure 15 shown, the pump 94 of the ink supply unit 9 of this embodiment is connected to the ink storage tank 91. In addition, the pump 94 is a pressure pump 942. By sending pressurized air into the ink storage tank 91, the ink I in the ink storage tank 91 is pressurized and the ink I is sent out to the tube 92. According to such a structure, by controlling the on / off of the pressure pump 942 or the output when it is on, the supply pressure of the ink I supplied to the print head 5 can be simply changed.

[0114] Next, a method for supplying the ink I from the ink storage tank 91 to the print head 5 will be described. Similar to the first embodiment, as Figure 16 shown, when the print head 5 is in the lower state where it is located below the ink storage tank 91 in the vertical direction, the pump control device 95 turns off the pressure pump 942. In this case, the ink I in the ink storage tank 91 can be supplied to the liquid storage tank 561 of the print head 5 by using the siphon principle. On the other hand, as Figure 17 shown, when the print head 5 is in the upper state where it is located above the ink storage tank 91 in the vertical direction, the pump control device 95 turns on the pressure pump 942, and the ink I in the ink storage tank 91 is forcibly supplied to the print head 5. According to such a method, compared with the case of the lower state, the supply pressure of the ink I supplied to the print head 5 increases, and even in the upper state, the ink I can be stably supplied to the print head 5.

[0115] Above, the supply method of the ink I to the print head 5 has been described, but the supply method of the ink I is not particularly limited. For example, the pressure pump 942 can also be turned on in the case of the lower state. In this case, as long as the output of the pressure pump 942 in the lower state is smaller than the output of the pressure pump 942 in the upper state, and the supply pressure of the ink I in the lower state is lower than the supply pressure of the ink I in the upper state. Also, in the upper state, the output of the pressure pump 942 can also be changed according to the height difference between the print head 5 and the ink storage tank 91. Specifically, it can also be that the greater the height difference between the print head 5 and the ink storage tank 91, that is, the higher the position of the print head 5, the greater the output of the pressure pump 942 is increased, and the supply pressure of the ink I is increased.

[0116] As described above, in the printing method of the printing system 1 of the present embodiment, the pump 94 is a pressure pump 942 that pressurizes the ink I in the ink storage tank 91. According to such a method, by driving the pressure pump 942, the ink I in the ink storage tank 91 can be forcibly supplied to the print head 5. In addition, by controlling the on / off of the pressure pump 942 or the output at the time of turning on, the supply pressure of the ink I can be easily changed.

[0117] Through such a second embodiment, the same effects as those of the above-described first embodiment can also be achieved.

[0118] Sixth Embodiment

[0119] Figure 18 It is a diagram showing the front end portion of the robot included in the printing system according to the sixth embodiment.

[0120] The printing system of the present embodiment is the same as the printing system of the above-described fourth embodiment except that it includes an ink ejection amount detection unit 70 that detects the ejection amount of the ink I. In addition, in the following description, regarding the present embodiment, the description will focus on the differences from the above-described embodiments, and the description of the same matters will be omitted. In addition, in the drawings of the present embodiment, the same reference numerals are assigned to the same structures as those of the above-described embodiments.

[0121] As Figure 18 shown, the printing system 1 of the present embodiment has an ink ejection amount detection unit 70 that detects the ejection amount of the ink I ejected from the print head 5. In addition, the ink ejection amount detection unit 70 includes a camera 71 that is fixed to the moving worktable 4 together with the print head 5 and an image processing unit 72 that processes the image captured by the camera 71. When the print head 5 moves along the printing track Q, the camera 71 is located immediately behind the print head 5 and captures the ink I that has landed on the object W. The image processing unit 72 detects the ejection amount of the ink I ejected from the print head 5 based on the image captured by the camera 71. For example, the image processing unit 72 detects the diameter of the point formed on the object W due to the landing of one drop of the ink I from the image obtained from the camera 71, and further detects the ejection amount of each drop of the ink I based on the detected diameter of the point.

[0122] However, as the structure of the ink ejection amount detection unit 70, as long as it can detect the ejection amount of each drop of the ink I, it is not particularly limited.

[0123] Further, the pump control device 95 corrects the output of the decompression pump 941 based on the ejection amount of the ink I detected by the image processing unit 72, thereby correcting the supply pressure of the ink I. Specifically, if the ejection amount of the ink I detected by the image processing unit 72 is more than a predetermined upper limit value, the pump control device 95 reduces the output of the decompression pump 941 to lower the supply pressure of the ink I to perform correction below the upper limit value. On the contrary, if the ejection amount of the ink I detected by the image processing unit 72 is less than a predetermined lower limit value, the pump control device 95 increases the output of the decompression pump 941 to increase the supply pressure of the ink I to perform correction above the lower limit value. According to such a method, the ejection amount of the ink I from the print head 5 is stable, and more excellent printing quality can be exhibited.

[0124] As described above, in the printing method of the printing system 1 of the present embodiment, the supply pressure of the ink I is corrected based on the ejection amount of the ink I from the print head 5. According to such a method, the ejection amount of the ink I from the print head 5 is stable, and more excellent printing quality can be exhibited.

[0125] Through such a sixth embodiment, the same effects as those of the above-described first embodiment can also be exhibited.

[0126] Seventh Embodiment

[0127] Figure 19 is an overall view of the printing system according to the seventh embodiment. Figure 20 is a flowchart of the ink supply method.

[0128] The printing system of the present embodiment is the same as the printing system of the above-described fourth embodiment except for the difference in the structure of the ink supply unit 9. In addition, in the following description, regarding the present embodiment, the description will be centered on the differences from the above-described embodiments, and the description of the same matters will be omitted. In addition, in the drawings of the present embodiment, the same reference numerals are assigned to the same structures as those of the above-described embodiments.

[0129] As Figure 19As shown, the ink supply unit 9 of the present embodiment has a pressure pump 942 connected to the ink storage tank 91, similarly to the above-described fifth embodiment. Further, pressurized air is supplied into the ink storage tank 91 by the pressure pump 942, whereby the ink I in the ink storage tank 91 is pressurized and the ink I is sent out to the pipe 92. Moreover, the ink supply unit 9 has a regulator 96 and a valve 97 disposed between the pressure pump 942 and the ink storage tank 91. The regulator 96 measures the pressure of the ink I in the ink storage tank 91, that is, the supply pressure for supplying the ink I to the print head 5. The valve 97 can be switched between a closed state in which the pressure pump 942 and the ink storage tank 91 are communicated with each other and an open state in which the pressure pump 942 and the ink storage tank 91 are cut off and the ink storage tank 91 is opened to the atmosphere. The opening and closing of the valve 97 is controlled by the pump control device 95. Further, in the present embodiment, the regulator 96 and the valve 97 are integrated, but it is not limited thereto, and they may be separate.

[0130] Next, a method for supplying the ink I from the ink storage tank 91 to the print head 5 will be described. As Figure 20 shown, in the present embodiment, first, the pump control device 95 sets the valve 97 to the closed state and turns on the pressure pump 942. Thereby, the pressure pump 942 is driven, the ink I in the ink storage tank 91 is pressurized, and the ink I in the ink storage tank 91 is supplied to the print head 5 via the pipe 92.

[0131] Next, the pump control device 95 detects the pressure of the ink I in the ink storage tank 91 via the regulator 96 and determines whether the detected pressure exceeds a predetermined upper limit value. When the pressure of the ink I in the ink storage tank 91 does not exceed the upper limit value, the pump control device 95 maintains this state. On the other hand, when the pressure of the ink I in the ink storage tank 91 exceeds the upper limit value, the pump control device 95 sets the valve 97 to the open state, stops the pressurization of the pressure pump 942, and opens the ink storage tank 91 to the atmosphere to reduce the pressure of the ink I in the ink storage tank 91. That is, the pump control device 95 uses the valve 97 to switch between a state in which the pressure of the ink I in the ink storage tank 91 is increased and a state in which the ink storage tank 91 is opened to the atmosphere to reduce the pressure of the ink I in the ink storage tank 91. Further, at this time, the pressure pump 942 may be kept on or may be turned off.

[0132] Next, the pump control device 95 detects the pressure of the ink I in the ink storage tank 91 via the regulator 96, and determines whether the detected pressure is less than a predetermined lower limit value. When the pressure of the ink I in the ink storage tank 91 is equal to or higher than the lower limit value, the pump control device 95 maintains its original state. On the other hand, when the pressure of the ink I in the ink storage tank 91 is less than the lower limit value, the pump control device 95 sets the valve 97 to the closed state, and raises the pressure of the ink I in the ink storage tank 91 again by the pressure pump 942.

[0133] By continuously performing the above control, the pump control device 95 maintains the pressure of the ink I in the ink storage tank 91 within a predetermined range. Thereby, the supply of the ink I to the print head 5 is stabilized, and the shortage of ink in the print head 5 during the printing operation is suppressed. Therefore, a predetermined amount of the ink I can be stably ejected from the print head 5, and a high printing quality can be achieved. In particular, in the present embodiment, the pressure of the ink I in the ink storage tank 91 can be maintained within a predetermined range only by opening and closing the valve 97, so the control becomes simple.

[0134] As described above, in the printing method of the printing system 1 of the present embodiment, a robot 2 having a print head 5 that ejects the ink I supplied from the ink storage tank 91 is used, and the ink I is ejected from the print head 5 while moving the print head 5 relative to the object W, thereby printing a printing pattern on the object W, and maintaining the pressure of the ink I in the ink storage tank 91 within a predetermined range. Thereby, the supply of the ink I to the print head 5 is stabilized, and the shortage of ink in the print head 5 during the printing operation is suppressed. Therefore, a predetermined amount of the ink I can be stably ejected from the print head 5, and a high printing quality can be achieved.

[0135] In addition, as described above, in the printing method using the printing system 1, there are: a pressure pump 942 that pressurizes the ink I in the ink storage tank 91; and a valve 97 that is disposed between the pressure pump 942 and the ink storage tank 91, and the valve 97 is used to switch between a state in which the pressure of the ink I in the ink storage tank 91 is increased by the pressure pump 942 and a state in which the ink storage tank 91 is opened to the atmosphere to reduce the pressure of the ink I in the ink storage tank 91. According to such a method, the pressure of the ink I in the ink storage tank 91 can be maintained within a predetermined range by simple control.

[0136] Through such a seventh embodiment, the same effects as those of the above-described first embodiment can also be achieved.

[0137] As described above, the printing system and the printing method of the present invention have been described with reference to the illustrated embodiments. However, the present invention is not limited thereto, and the structures and processes of each part can be replaced with any structures and processes having the same functions. In addition, any other structures and processes can be added to the present invention. In addition, the embodiments can be appropriately combined.

Claims

1. A printing system, characterized in that: have: a robot including a robot arm that supports and moves a printing head that ejects ink; and an ink storage unit for storing the ink to be supplied to the print head, The ink storage section is located vertically above the movable range of the print head.

2. The printing system according to claim 1, characterized in that: The ink storage unit is disposed separately from the robot.

3. The printing system according to claim 2, characterized in that: A pipeline is also provided to connect the ink storage unit and the printing head.

4. The printing system according to claim 3, characterized in that: The pipeline connects the ink storage unit and the print head via the upper side in the vertical direction of the robot.

5. The printing system according to claim 3, characterized in that: The printing head further includes an on-off valve that switches between a state in which the ink is allowed to be supplied from the ink storage portion to the printing head and a state in which the ink is restricted to be supplied from the ink storage portion to the printing head.

6. The printing system according to claim 5, characterized in that: The opening and closing valve is arranged between the printing head and the pipeline.

7. The printing system according to claim 1, characterized in that: It also has a fixing component for fixing the printing head to the robot arm, The ink storage portion is disposed on the fixing member.

8. The printing system according to claim 7, characterized in that: The ink storage section is arranged on a side of the print head that is opposite to a discharge direction of the ink.

9. The printing system according to claim 1, characterized in that: A frame is also provided for suspending and supporting the robot.

10. A printing method, characterized in that: Printing work on an object is performed using a robot having a robot arm that supports and moves a print head that ejects ink. The printing operation is performed by moving the print head to a position vertically below an ink storage portion storing the ink supplied to the print head.

11. A printing method, characterized in that: Using a robot equipped with a print head for ejecting ink supplied from an ink storage unit, ejecting the ink from the print head while moving the print head and an object relative to each other, thereby printing a print pattern on the object, The supply pressure of the ink supplied from the ink storage portion to the print head is changed according to the position of the print head relative to the ink storage portion.

12. The printing method according to claim 11, characterized in that: The supply pressure when the print head is located on an upper side in a vertical direction of the ink storage portion is higher than the supply pressure when the print head is located on a lower side in a vertical direction of the ink storage portion.

13. The printing method according to claim 11, characterized in that: The printed pattern is a floral pattern.

14. The printing method according to claim 11, characterized in that: supplying the ink in the ink storage unit to the print head using a pump, The supply pressure is changed by controlling the driving of the pump.

15. The printing method according to claim 14, characterized in that: The ink storage unit is connected to the printing head by a pipeline, The pump is a pressure reducing pump for reducing the pressure in the pipeline.

16. The printing method according to claim 14, characterized in that: The pump is a pressure pump that pressurizes the ink in the ink storage section.

17. The printing method according to claim 11, characterized in that: The supply pressure is corrected based on the ejection amount of the ink from the print head.

18. A printing method, characterized in that: Using a robot equipped with a print head for ejecting ink supplied from an ink storage unit, ejecting the ink from the print head while moving the print head and an object relative to each other, thereby printing a print pattern on the object, The pressure of the ink in the ink storage portion is maintained within a predetermined range.

19. The printing method according to claim 18, characterized in that: have: a pressure pump for pressurizing the ink in the ink storage portion; and a valve disposed between the pressure pump and the ink storage portion, The valve is used to switch between a state in which the pressure of the ink in the ink storage section is increased by the pressure pump and a state in which the pressure of the ink in the ink storage section is reduced by opening the ink storage section to the atmosphere.

20. A printing system, characterized in that: have: an ink storage portion storing ink; a robot including a print head for ejecting the ink supplied from the ink storage portion; and The supply pressure control unit changes the supply pressure of the ink supplied from the ink storage unit to the print head according to the position of the print head relative to the ink storage unit.

Images