Liquid ejection device

Abstract

To provide a device for discharging liquid that allows liquid in a liquid supply passage to be returned to a head with a simple configuration.SOLUTION: A liquid discharging device includes: a head 2 that discharges liquid; a liquid tank 330 that stores the liquid; a liquid supply passage 321 from the liquid tank 330 to the head 2; a pressure source 331 that pressurizes inside of the liquid tank 330; an opening / closing valve 350 that opens / closes a compressed air passage 320 connecting the pressure source 331 and the liquid tank 330; and an ejector 340 having an inflow port 341, a suction port 342, and a drain port 343. The suction port 342 of the ejector 340 communicates with the liquid tank 330, and the inflow port 341 communicates with the pressure source 331. The device has: an opening / closing valve 352 that opens / closes a suction passage 323 connecting the suction port 342 of the ejector 340 and the liquid tank 330; and an opening / closing valve 351 that opens / closes a branch passage 322 connecting the inflow port 341 of the ejector 340 and the pressure source 331.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for discharging liquid. [Background technology]

[0002] 2. Description of the Related Art Some liquid ejection devices use a liquid storage means that recovers liquid remaining in a liquid supply path (pipe) that runs from a liquid tank to a head.

[0003] Conventionally, for example, a printer is known that includes a main tank, a sub-tank mounted on an ejection unit, and a recording head, and pressurizes the inside of the sub-tank to cause the ink contained in the sub-tank to flow back into the main tank, which is open to the atmosphere (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-221602 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration disclosed in Patent Document 1 has a problem in that the path for pressurizing the sub-tank mounted in the ejection unit together with the head becomes long, increasing the head scanning load.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to make it possible to return liquid in a liquid supply path to a head to a liquid tank with a simple configuration. [Means for solving the problem]

[0007] In order to solve the above problems, a liquid ejection device according to the present invention comprises: a head that ejects liquid; a liquid tank for containing the liquid; a liquid supply path from the liquid tank to the head; a pressure source that applies pressure to the inside of the liquid tank; a first valve that opens and closes a path connecting the pressure source and the liquid tank; an ejector having an inlet port, a suction port, and an outlet port; the suction port of the ejector communicates with the liquid tank; the inlet port of the ejector is in communication with the pressure source; Opening and closing a path between the inlet port of the ejector and the pressure source No. 2 The argument and Opening and closing a path between the suction port of the ejector and the liquid tank Third The argument and a fourth valve that switches the communication destination of the liquid supply path between the head and the atmosphere; Equipped with The composition was as follows. [Effects of the Invention]

[0008] According to the present invention, the liquid in the liquid supply path to the head can be returned to the liquid tank with a simple configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram of a device for discharging liquid according to a first embodiment of the present invention. [Figure 2] 10 is an explanatory diagram illustrating a liquid recovery operation mode of the embodiment. FIG. [Figure 3] 3A to 3C are explanatory diagrams illustrating the open / closed states of each valve in each operation mode of the embodiment. [Figure 4] FIG. 10 is an explanatory diagram of a liquid ejecting device according to a second embodiment of the present invention. [Figure 5] 3A to 3C are explanatory diagrams illustrating the open / closed states of each valve in each operation mode of the embodiment. [Figure 6] FIG. 10 is an illustrative side view of a liquid ejecting device according to a third embodiment of the present invention. [Figure 7] FIG. [Figure 8]10A and 10B are explanatory diagrams illustrating an example of a drawing operation according to the embodiment. [Figure 9] FIG. 2 is a perspective view illustrating an example of a discharge unit. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] FIG. 2 is a cross-sectional view illustrating one nozzle portion for explaining an example of a head. [Figure 13] FIG. 4 is an explanatory diagram of an example of a driving voltage for explaining the operation of a head. [Figure 14] FIG. 10 is an explanatory diagram illustrating printing an aircraft as a drawing object using a liquid ejecting device according to a fourth embodiment of the present invention. [Figure 15] FIG. 2 is a perspective view of the liquid ejection device. [Figure 16] FIG. 10 is a perspective view illustrating a device for discharging liquid according to a fifth embodiment of the present invention. [Figure 17] FIG. 2 is a perspective view illustrating a drive unit of the device. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram for explaining the embodiment.

[0011] The liquid ejecting device 1000 includes an ejection unit 1 having a head 2 that ejects liquid, and a liquid tank 330 that contains liquid 311 to be supplied to the head 2.

[0012] Liquid 311 is supplied under pressure from a liquid tank 330 to the head 2 via a liquid supply path 321. The head 2 has an internal valve mechanism, and ejects the pressurized liquid (ink) by opening the valve appropriately in response to an image signal.

[0013] The liquid tank 330 is provided with a pressure source 331 that pressurizes the liquid tank 330. The pressure source 331 is configured with a regulator that adjusts the pressure generated by the compressor 230 to a required pressure. The pressure source 331 and the air space in the liquid tank 330 are connected via a compressed air path 320 that serves as an air path. The compressed air path 320 is provided with an on-off valve 350 that is a first valve that opens and closes the compressed air path 320.

[0014] The ejector 340 has an inlet port 341, a suction port 342, and an outlet port 343. The ejector 340 generates negative pressure in the suction port 342 by causing air to flow from the inlet port 341 to the outlet port 343 at high speed.

[0015] Therefore, the compressed air path 320 is branched between the pressure source 331 and the on-off valve 350, and the branch path 322 is connected to the inlet port 341 of the ejector 340. In addition, the suction port 342 of the ejector 340 is connected to the air layer of the liquid tank 330 via the suction path 323.

[0016] A branch path 322 connecting the inlet port 341 of the ejector 340 and the pressure source 331 is provided with an on-off valve 351, which is a second valve that opens and closes the branch path 322. A suction path 323 connecting the suction port 342 of the ejector 340 and the liquid tank 330 is provided with an on-off valve 352, which is a third valve that opens and closes the suction path 323.

[0017] A three-way valve 353, which is a fourth valve, is provided near the head 2 of the liquid supply path 321 to switch the communication destination of the liquid supply path 321 between the head 2 and the atmosphere. It is also possible to combine a plurality of on-off valves instead of the three-way valve 353. The three-way valve 353 is mounted on the discharge unit 1.

[0018] Next, the operation of this embodiment will be described with reference to Figures 2 and 3. Figure 2 is an explanatory diagram illustrating the liquid recovery operation mode of this embodiment, and Figure 3 is an explanatory diagram illustrating the open / closed state of each valve in each operation mode of this embodiment. Note that dashed arrows in Figures 1 and 3 indicate the direction of air flow, and solid arrows indicate the direction of liquid (ink) flow.

[0019] In this embodiment, there are two operation modes: Mode A and Mode B. Mode A is a printing operation mode in which liquid is ejected from the head 2. Mode B is a recovery operation mode in which liquid is recovered from the liquid supply path 321 from the liquid tank 330 to the head 2.

[0020] 3, in mode A, three-way valve 353 is set to a state in which liquid tank 330 and head 2 are in communication with each other, on-off valves 351 and 352 are closed, and on-off valve 350 is opened. As a result, as shown in FIG. 1, air from pressure source 331 is supplied to liquid tank 330 through compressed air path 320 as indicated by arrow B, and liquid 311 in liquid tank 330 is pressurized.

[0021] Therefore, the liquid 311 is supplied to the head 2 from the liquid tank 330 via the liquid supply path 321, and is ejected from the head 2 in response to an image signal or the like.

[0022] After printing by head 2 is completed, the mode shifts to mode B.

[0023] In mode B, first, the on-off valve 350 is closed. Next, the on-off valve 352 is opened. As a result, the air layer in the liquid tank 330 is discharged to the outside from the suction port 342 of the ejector 340 via the discharge port 343.

[0024] Thereafter, when the on-off valve 351 is opened, air flows at high speed from the inlet port 341 of the ejector 340 to the outlet port 343 (arrows D and E), and a negative pressure is generated in the suction port 342 .

[0025] Therefore, when the three-way valve 353 is switched to open the liquid tank 330 to the atmosphere through the liquid supply path 321, air flows in in the direction of the arrow C, as shown in Figure 2, causing the liquid 311 in the liquid supply path 321 to flow back and be collected in the liquid tank 330.

[0026] In this way, the air path (compressed air path 320) that pressurizes the liquid tank 330 is used to create a negative pressure inside the liquid tank 330, causing the liquid 311 in the liquid supply path 321 to flow backward, and the liquid 311 is collected.

[0027] Therefore, the liquid in the liquid supply path to the head can be returned to the liquid tank and recovered with a simple configuration, without increasing the amount of piping between the liquid tank 330 fixed to the apparatus body and the discharge unit 1.

[0028] In particular, when the object onto which the liquid is to be ejected (the object to be drawn, the object onto which an image is to be formed) is a truck body or an aircraft fuselage, the liquid supply path 321 becomes long, and therefore the effect of reducing piping costs and tube load by being able to supply and recover the liquid using the same piping becomes even greater.

[0029] In this embodiment, three-way valve 353 is provided and liquid supply path 321 is open to the atmosphere when recovering liquid, but liquid can also be allowed to flow back even if the nozzle of head 2 is opened after depressurizing liquid tank 330. However, because the nozzle of head 2 has a small diameter and presents a large resistance to air intake, liquid can be recovered more quickly if liquid supply path 321 is open to the atmosphere.

[0030] Next, a second embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram of a device for discharging liquid according to the second embodiment.

[0031] In this embodiment, in the configuration of the first embodiment, a discharge path 371, which serves as a liquid outlet for taking out the liquid 311 to the outside, is connected to the bottom of the liquid tank 330. The discharge path 371 has a discharge port facing a discharge container 370, and is provided with an on-off valve 354 for opening and closing the discharge path 371.

[0032] Next, the operation of this embodiment will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram illustrating the open / closed state of each valve in each operation mode of this embodiment.

[0033] The states of the on-off valves 350 to 352 and the three-way valve 353 in Mode A and Mode B are the same as those in the first embodiment. In Mode A and Mode B, the on-off valve 354 in the discharge path 371 is closed.

[0034] In this embodiment, after printing in mode A and recovering the liquid 311 into the liquid tank 330 in mode B, the process moves to mode C.

[0035] In mode C, on-off valve 350 is opened, on-off valves 351 and 352 are closed, and three-way 353 is set in a state where liquid tank 330 communicates with head 2. When on-off valves 350 to 352 and 354 are set in the state of mode C, air pressurized by compressor 230 of pressure source 331 is supplied to liquid tank 330, and liquid 311 in liquid tank 330 flows as shown by arrow H, and the liquid can be taken out from discharge path 371 to discharge container 370.

[0036] At this time, if the liquid tank 330 is emptied, cleaning liquid can be poured into the liquid tank 330 to clean the liquid tank 330 and the liquid supply path 321 up to the head 2. In other words, it is possible to clean the piping of the device without wasting liquid.

[0037] Next, a third embodiment of the present invention will be described with reference to Figures 6 and 7. Figure 6 is a side view of the device for discharging liquid according to this embodiment, and Figure 7 is a plan view of the same.

[0038] The liquid ejecting device 1000 is provided facing a drawing target 100, which is an example of an object, and includes an ejection unit 1 that ejects ink, which is an example of a liquid, toward the drawing target 100.

[0039] The liquid discharging device 1000 includes a Z-axis rail 103 that holds the discharging unit 1 movably in the Z-axis direction, an X-axis rail 101 that holds the Z-axis rail 103 movably in the X-axis direction, and a Y-axis rail 102 that holds the X-axis rail 101 movably in the Y-axis direction. The X-axis rail 101, the Y-axis rail 102, and the Z-axis rail 103 are examples of a guide portion and a holder that movably hold the discharging unit 1.

[0040] The liquid ejection device 1000 also includes a Z-direction drive unit 111 that moves the ejection unit 1 in the Z-axis direction along the Z-axis rail 103, an X-direction drive unit 112 that moves the Z-axis rail 103 in the X-axis direction along the X-axis rail 101, and a Y-direction drive unit 113 that moves the X-axis rail 101 in the Y-axis direction along the Y-axis rail 102.

[0041] Next, an example of the drawing operation of this embodiment will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram for explaining the drawing operation, in which (a) is an explanatory diagram showing the drawing surface showing the movement path of the discharge unit during drawing, as viewed from the front, and (b) is an explanatory plan view.

[0042] When a drawing command is received, the discharge unit 1 moves to the print start standby position 120 shown in Figure 8(a), and then performs printing based on the image information while moving in the +X direction. When the discharge unit 1 leaves the drawing area, it stops at the reversal position 121. Here, it is determined whether drawing has ended, and if there is drawing data, the discharge unit 1 moves in the -Y direction, and then performs printing while moving in the -X direction. This operation continues until there is no more drawing data.

[0043] Although the object 100 is illustrated as being in the form of a flat plate, it may be a curved surface such as the body of a vehicle, such as a car, truck, or airplane, as long as it is nearly vertical or has a large radius of curvature.

[0044] Next, an example of a discharge unit will be described with reference to Figures 9 to 11. Figure 9 is a perspective view of the discharge unit, Figure 10 is a side view of the same, and Figure 11 is a front view of the head portion of the same.

[0045] The discharge unit 1 has a head section (liquid discharge section) 20 that discharges liquid, and the head section 20 is integrally provided with a cleaning mechanism section 500 that includes a wiping member 501 that wipes the nozzle surface 202a, which is the discharge surface. The discharge unit 1 also includes the three-way valve 353 described in the above embodiment.

[0046] In the head unit 20, a plurality of (here, five) heads 2 (color heads 2C1 to 2C4, white head 2W) that eject liquids (inks) of different colors are held by a holder member 21. The color heads 2C1 to 2C4 eject inks of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K), respectively.

[0047] The head 2 has an array of nozzles 202 that eject liquid, and is held by a holder member 21 that serves as a housing, with the array direction of the nozzles 202 inclined with respect to the Y direction.

[0048] The cleaning mechanism 500 includes a wiping member 501 that wipes the nozzle surface 202a of the head 2, and a cleaning liquid ejection unit 502 that is a cleaning liquid application unit that ejects or drops cleaning liquid onto the nozzle surface 202a of the head 2.

[0049] The wiping member 501 and the cleaning liquid discharge part 502 are attached to and held by a moving member 505 .

[0050] Meanwhile, guide members 506, 506 having guide grooves 506a are attached to both sides of holder member 21 of head unit 20. A support shaft 505a of moving member 505 is movably fitted into guide groove 506a of guide member 506. In other words, holder member 21 serves as a housing that holds head 2 and movably supports moving member 505.

[0051] As a result, the moving member 505 is able to move along the guide groove 506a between a position where the wiping member 501 faces the nozzle surface 202a of the head 2 and a position where the wiping member 501 is retracted from the nozzle surface 202a.

[0052] A rotary air cylinder 510 is provided as a driving means for moving the moving member 505. One end of an arm 511 is attached to the rotary air cylinder 510, and the other end of the arm 511 has an elongated hole 511a which is movably fitted into a pin member 505b provided on the side of the moving member 505.

[0053] As a result, by driving the rotary air cylinder 510 to rotate the arm 511 in the direction of arrow A, the moving member 505 is guided by the guide groove 506a of the guide member 506 and moves as shown by arrow B from the retracted position shown by the imaginary line in Fig. 20 to the wiping end position, which is also the opposing position shown by the solid line. This movement of the moving member 505 allows the wiping member 501 to wipe the nozzle surface 202a of the head 2.

[0054] In this way, the discharge unit 1 integrally includes the head section 20, which is a liquid discharge section that discharges liquid, and the cleaning mechanism section 500 that wipes and cleans the nozzle surface 202a of the head 2 of the head section 20.

[0055] This allows the nozzle surface 202a of the head 2 to be wiped and cleaned when the discharge unit 1 is not discharging liquid, regardless of the position of the discharge unit 1, and the discharge surface (nozzle surface) can be cleaned at any time when necessary.

[0056] Next, an example of a head will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view of one nozzle portion of the head. Fig. 22(a) shows the state in which the nozzle is closed, and Fig. 22(b) shows the state in which the nozzle is open.

[0057] The head 2 is provided with a nozzle 202 at the tip for discharging liquid, and is provided with a hollow housing 204 provided near the nozzle 202 with an inlet 203 through which pressurized liquid (ink) is injected.

[0058] Within the housing 204 are a piezoelectric element 205 that expands and contracts in response to the application of an external voltage, a valve body 207 that opens and closes the nozzle 202, and a valve body moving means 208 that is positioned between the valve body 207 and the piezoelectric element 205 and moves the valve body 207 forward and backward relative to the nozzle 202.

[0059] The piezoelectric element 205 is housed in a case 215, and is connected to a pair of wiring members 210a and 210b for applying voltage, which are drawn out to the outside.

[0060] A sealing member 206 is disposed between the valve body 207 and the housing 204 to prevent the pressurized liquid injected from the injection port 203 from entering the piezoelectric element 205. This forms a liquid chamber 209 into which the pressurized liquid is injected from the injection port 203.

[0061] The housing 204 is a cylindrical body having a cylindrical or rectangular shape, and is closed except for the nozzle 202 and the injection port 203. The nozzle 202 is an opening formed at the tip of the housing 204, and ejects the liquid 311. The injection port 203 is provided on the side of the housing 204 near the nozzle 202, and pressurized liquid is continuously supplied through the injection port 203.

[0062] The piezoelectric element 205 is made of zirconia ceramics, etc. A driving waveform (driving voltage) is applied to the piezoelectric element 205 via wiring members 210a and 210b.

[0063] The sealing member 206 is, for example, a packing, an O-ring, or the like, and by fitting the sealing member 206 onto the outside of the valve body 207, the liquid is prevented from flowing from the injection port 203 side to the piezoelectric element 205 side.

[0064] The valve element moving means 208 has a deformation portion 208a with a generally trapezoidal cross section, which is formed from a restorable elastic member made of rubber, soft resin, thin metal plate, or the like. A connecting portion 208e, which corresponds to the upper side of the generally trapezoidal cross section of the deformation portion 208a, is fixed to the surface of the base end side of the valve element 207. The long side of the deformation portion 208a, which corresponds to the bottom side of the generally trapezoidal cross section, is connected to a bent side portion 208d. The radial center portion of the bent side portion 208d is connected to the guide portion 208c, and the portion between the radial center portion and the end portion is connected to a fixed portion 212, one end of which is connected to the case 215.

[0065] When a predetermined voltage is applied to the piezoelectric element 205 of this valve body moving means 208, the piezoelectric element 205 expands, and as shown in Figure 12(b), the guide portion 208c moves toward the nozzle 202 by, for example, a distance e, and the area near the center of the bent side portion 208d is pushed in.

[0066] At this time, because the outer circumferential side of guide portion 208c is connected to fixed portion 212, bent side portion 208d is displaced in the direction of the arrow starting from the connection portion with fixed portion 212. When bent side portion 208d is displaced in the direction of the arrow, deforming portion 208a expands, and connection portion 208e with valve body 207 is pulled in the direction of the arrow.

[0067] By this deformation of the deformation portion 208a of the valve element moving means 208, the valve element 207 fixed to the connecting portion 208e of the deformation portion 208a is pulled in by a distance d, and the nozzle 202 is opened.

[0068] That is, as the piezoelectric element 205 expands, the guide portion 208c moves by a distance e toward the nozzle 202, and the valve body 207 moves by the distance in the direction opposite to the movement direction of the guide portion 208 (the expansion direction of the piezoelectric element 205).

[0069] Here, by adjusting the distance between the connecting portion 208e with the valve body 207 at the deformation portion 208a of the valve body moving means 208 and the bending side portion 208d, and the length of the bending side portion 208d, the movement amount of the valve body 207 can be made longer than the displacement amount of the piezoelectric element 205.

[0070] In other words, the valve element moving means 208 can amplify the displacement of the piezoelectric element 205 and can reduce the displacement of the piezoelectric element 205, thereby allowing the piezoelectric element 205 to be made smaller.

[0071] Next, the operation of the head 2 will be described with reference to Fig. 13. Fig. 13 is an explanatory diagram of an example of a driving voltage used to explain the operation.

[0072] In the head 2, when no voltage is applied to the piezoelectric element 205, the piezoelectric element 205 is in a contracted state, and therefore no force is applied to the valve element moving means 208 by the piezoelectric element 205. At this time, the deformation portion 208a of the valve element moving means 208 is in a swollen state (normal state) as shown in Figure 12(a), and the valve element 207 is urged toward the nozzle 202 by the elastic force of the deformation portion 208a. Therefore, the nozzle 202 is closed by the end face of the valve element 207, and liquid 311 is not discharged from the nozzle 202.

[0073] 13(a), when a voltage (+EV) of waveform P1 is applied to piezoelectric element 205, piezoelectric element 205 expands, and as described above, deformation portion 208a of valve element moving means 208 deforms, pulling valve element 207 in the direction of the arrow shown in Fig. 12(b). As a result, valve element 207 opens nozzle 202, and pressurized liquid 311 injected from injection port 203 is discharged from nozzle 202.

[0074] On the other hand, as shown in Figure 13(b), a waveform P2 may be applied to the piezoelectric element 205 in which the voltage (+EV) of the waveform P2 disappears midway, or as shown in Figure 13(c), the voltage of the waveform that should be applied may not be applied to the piezoelectric element 205 due to a power outage or the like.

[0075] At this time, the piezoelectric element 205 maintains its contracted state, and the deforming portion 208a of the valve element moving means 208 returns to the normal state shown in Fig. 12(a). Therefore, the valve element 207 maintains the state in which the nozzle 202 is closed, and the liquid 311 is not discharged from the nozzle 202.

[0076] This reduces the risk of the liquid 311 accidentally leaking out of the nozzle 202 or clogging the nozzle, even in the event of a power outage or the like.

[0077] Next, a fourth embodiment of the present invention will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is an explanatory diagram illustrating printing an aircraft as a drawing object using a device for discharging liquid according to this embodiment, and Fig. 15 is a perspective explanatory diagram of the device for discharging liquid.

[0078] The liquid ejection device 1000 is equipped with a linear rail 404 that moves the ejection unit 1, which is a moving body, back and forth in a straight line, and an articulated robot 405 that moves the linear rail 404 to a predetermined position as appropriate and holds it in that position.

[0079] The articulated robot 405 is equipped with a robot arm 405a that has multiple joints that allow it to move freely like a human arm, and the tip of the robot arm 405a can be moved freely and positioned accurately.

[0080] The articulated robot 405 may be, for example, a six-axis controlled industrial robot equipped with six axes, i.e., six joints. With a six-axis articulated robot, by teaching information regarding its operation in advance, it is possible to very accurately and quickly position the linear rail 404 at a predetermined position on the drawing target 100 (aircraft). The robot 405 is not limited to a six-axis robot, and an articulated robot equipped with an appropriate number of axes, such as five axes or seven axes, may be used.

[0081] A fork-shaped support member 424 that branches into two branches is provided on the robot arm 405a of this robot 405, and a vertical linear rail 423a is attached to the tip of the left branch 424a of this support member 424, and a vertical linear rail 423b is attached to the tip of the right branch 424b so that they are parallel to each other.

[0082] The discharge unit 1 is movably supported by a linear rail 404, and both ends of the linear rail 404 are supported by two vertical linear rails 423a and 423b so as to be bridged over the two rails.

[0083] The discharge unit 1 includes a plurality of heads 2 that discharge liquid of each color, for example, black, cyan, magenta, yellow, and white, or a head 2 that has a plurality of nozzle rows. Liquid of each color is supplied under pressure from a tank 330 to each head 2 or each nozzle row of the head 2 of the discharge unit 1.

[0084] In this liquid ejection device 1, a robot 405 moves a linear rail 404 to a position opposite the required drawing area of ​​the object 100, and the ejection unit 1 is moved along the linear rail 404 according to the print data while driving the head 2 to perform printing.

[0085] Then, when printing of one line is completed, the vertical linear rails 423a and 423b are driven to move the head 2 of the discharge unit 1 from one line to the next line.

[0086] By repeating this operation, printing can be performed on the desired printing area of ​​the object 100 to be drawn.

[0087] At this time, the moving distance of the discharge unit 1 (head 2) becomes longer, but the discharge unit 1 is provided with a wiping member 501, and can clean the nozzle surface 202a of the head 2 at any time.

[0088] This allows for continuous high-quality printing with minimal downtime.

[0089] Next, a fifth embodiment of the present invention will be described with reference to Figures 16 and 17. Figure 16 is a perspective view of a device for discharging liquid according to this embodiment, and Figure 17 is a perspective view of a drive unit of the device.

[0090] Liquid ejection device 1000 includes a movable frame unit 802 that is installed facing drawing target 100 having a curved surface, such as a vehicle hood. A movable unit 813 is attached to left and right frame members 810 and 811 that make up frame unit 802 so as to span between frame members 810 and 811 and be capable of moving up and down in the vertical direction (Y direction).

[0091] The movable unit 813 is equipped with a drive unit 803 incorporating a motor that is arranged so as to be able to move back and forth horizontally (in the X direction) on the movable unit 813, and an ejection unit 1 that is attached to the drive unit 803 and ejects liquid toward the object 100 to be drawn.

[0092] The device also includes a controller 805 that controls the ejection of liquid from the ejection unit 1, the reciprocating movement of the drive unit 803, and the elevation of the movable unit 813, and an information processing device 806 such as a PC (personal computer) that issues instructions to the controller 805. A database section (DB section) 807 that records and saves information about the object 100 to be drawn, such as its shape and size, is connected to the information processing device 806.

[0093] The frame unit 802 comprises upper, lower, left and right frame members 808, 809, 810, 811 formed from metal pillars or the like, and left and right leg members 812a, 812b attached horizontally and at right angles to both sides of the lower frame member 809 to enable the frame unit 802 to stand on its own.

[0094] A movable unit 813 spanning the left and right frame members 810 and 811 is configured to be able to move up and down while supporting the drive unit 803 .

[0095] The drawing target 100 is placed perpendicular to the liquid discharge direction (Z direction), that is, facing the plane formed by the upper, lower, left and right frame members 808, 809, 810, and 811 of the frame unit 802.

[0096] In this case, the object 100 can be positioned at a predetermined position where printing is to be performed by, for example, using a chuck attached to the tip of the arm of an articulated arm robot to suction and hold the back side of the drawing area of ​​the object 100. Using an articulated arm robot makes it possible to accurately position the object 100 at the printing position, and also makes it possible to change the posture of the object 100 as needed.

[0097] 17, the drive unit 803 is arranged so as to be able to move back and forth in the horizontal direction (X direction) on the movable unit 813. The movable unit 813 is composed of a rail 830 arranged horizontally so as to span between the left and right frame members 810, 811 of the frame unit 802, a rack gear 831 arranged parallel to the rail 830, a linear guide 832 fitted onto a part of the rail 830 and moving while sliding, a pinion gear unit 833 connected to the linear guide 832 and meshing with the rack gear 831, a motor 834 with a reducer 836 that rotates and drives the pinion gear unit 833, and a rotary encoder 835 for detecting the printing point position.

[0098] By driving the motor 834 (forward or reverse), the discharge unit 1 is moved rightward or leftward along the movable unit 813. The drive section 803 functions as a drive mechanism for the X direction of the discharge unit 1. Limit switches 837a and 837b are attached to both sides of the housing of the reducer 836.

[0099] The discharge unit 1 includes a plurality of heads 2 that discharge liquid of each color, for example, black, cyan, magenta, yellow, and white, or a head 2 that has a plurality of nozzle rows. The liquid of each color is supplied under pressure from a tank 330 to each head 2 or each nozzle row of the head 2 of the discharge unit 1, in the same manner as the liquid supply system described above.

[0100] In this liquid discharging device 1, the movable unit 813 is moved in the Y direction, and the discharging unit 1 is moved in the X direction, thereby drawing (printing) a desired image on the drawing target 100.

[0101] At this time, the moving distance of the discharge unit 1 (head 2) becomes longer, but the discharge unit 1 is provided with a wiping member 501, and can clean the nozzle surface 202a of the head 2 at any time.

[0102] This allows for continuous high-quality printing with minimal downtime.

[0103] Furthermore, the "liquid ejecting device" in the present invention includes a device that is equipped with a head, a head module, or a liquid ejection unit and ejects liquid by driving a liquid ejection head. The liquid ejecting device includes not only a device that can eject liquid onto an object onto which the liquid can adhere, but also a device that ejects liquid into air or liquid.

[0104] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0105] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0106] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0107] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0108] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0109] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0110] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0111] The liquid to be ejected may have any viscosity and surface tension that allows it to be ejected from the head, but is not particularly limited thereto. Preferably, the viscosity of the ejected liquid is 30 mPa·s or less at room temperature and pressure, or upon heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a surfactant, or the like, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These liquids can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic devices or light-emitting elements, or resist patterns for electronic circuits, and liquid materials for 3D modeling.

[0112] Energy sources for ejecting liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode. [Explanation of symbols]

[0113] 1 Discharge unit 2 heads 321 Liquid supply path 330 Liquid Tank 331 Pressure Source 340 Ejector 350 On-off valve (first valve) 351 On-off valve (second valve) 352 On-off valve (third valve) 353 Three-way valve (fourth valve) 1000 Liquid discharging device

Claims

1. a head that ejects liquid; a liquid tank for containing the liquid; a liquid supply path from the liquid tank to the head; a pressure source that applies pressure to the inside of the liquid tank; a first valve that opens and closes a path connecting the pressure source and the liquid tank; an ejector having an inlet port, a suction port, and an outlet port; the suction port of the ejector communicates with the liquid tank; the inlet port of the ejector is in communication with the pressure source; a second valve that opens and closes a path between the inlet port of the ejector and the pressure source; a third valve that opens and closes a path connecting the suction port of the ejector and the liquid tank; a fourth valve that switches the communication destination of the liquid supply path between the head and the atmosphere. A liquid ejection device comprising:

2. When discharging the liquid from the head, the first valve is opened, the third valve is closed, the second valve is closed, and the fourth valve is switched to a state in which the liquid supply path is connected to the head; When recovering the liquid in the liquid supply path to the liquid tank, the first valve is closed, the third valve is closed, the second valve is opened, and the fourth valve is switched to a state in which the liquid supply path is in communication with the atmosphere.

2. The liquid ejection device according to claim 1.

3. A liquid outlet is provided at the bottom of the liquid tank to take out the liquid to the outside.

3. The liquid ejection device according to claim 1 or 2.

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