3D printing device

Abstract

This 3D printer 10 comprises an inkjet head 200 for ejecting ink, a head tank 210 for storing the ink supplied to the inkjet head 200, an ink tank 220 for storing the ink supplied to the inside of the head tank 210, piping 230 for connecting the head tank 210 and the ink tank 220, a vacuum pump 242 for generating high negative pressure, a first pressure line 271 for connecting the head tank 210 and the vacuum pump 242, and a controller 110 for performing control such that the high negative pressure generated by the vacuum pump 242 is applied to the head tank 210 via the first pressure line 271 when ink is supplied from the ink tank 220 to the inside of the head tank 210 via the piping 230.

Description

[Technical Field]

[0001] The present disclosure relates to a technology for three-dimensional printing by ejecting ink from an ejection head that ejects ink. [Background technology]

[0002] Patent document 1 describes a method for replacing ink cartridges that includes an ejection head that ejects ink, and that has two ink flow paths to which ink cartridges that store ink to be supplied into the ejection head are detachably connected, and that when the ink in at least one of the ink cartridges becomes empty and it is replaced with a new ink cartridge, it is possible to replace the ink cartridge without introducing air bubbles into the ejection head.

[0003] 8 shows the peripheral configuration of a conventional ejection head, which differs from the ejection head described in Patent Document 1 in that ink is supplied to an inkjet head 200, which is an ejection head, by a head tank 510 that is not detachable from the inkjet head 200. In the configuration shown in the figure, ink is supplied to the head tank 510 from an external ink tank 220 by a pump 520. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-170637 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration shown in FIG. 8, ink is supplied from the ink tank 220 to the head tank 510 using a dedicated pump 520. If the ink supply is performed using a necessary component provided for another function, the dedicated pump 520 becomes unnecessary, thereby reducing the manufacturing costs of the entire device.

[0006] An object of the present disclosure is to provide a technology that makes it possible to reduce the manufacturing costs of the entire device by eliminating the need for a dedicated pump for supplying ink from an ink tank to a head tank. [Means for solving the problem]

[0007] In order to achieve the above object, the three-dimensional printing device of the present disclosure includes an ejection head that ejects ink, a head tank that stores ink to be supplied to the ejection head, an ink tank that stores ink to be supplied into the head tank, piping that connects the head tank and the ink tank, a negative pressure generating device that generates negative pressure, a first pressure line that connects the head tank and the negative pressure generating device, and a control unit that controls the negative pressure generated by the negative pressure generating device to be applied to the head tank via the first pressure line when ink is supplied from the ink tank into the head tank via the piping. The head tank is divided into a first chamber and a second chamber, the first chamber is connected to an ink tank via a pipe, is connected to a negative pressure generating device via a first pressure line, and is further connected to a first end of an ink flow path in the ejection head via a first opening and closing device, and when ink is supplied from the ink tank to the first chamber in the head tank, the control unit controls the first opening and closing device to a closed state, and then controls so as to apply negative pressure to the first chamber of the head tank via the first pressure line. It is characterized by: [Effects of the Invention]

[0008] According to the present disclosure, it is possible to eliminate the need for a dedicated pump for supplying ink from an ink tank to a head tank, thereby reducing the manufacturing costs of the entire device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a schematic configuration of a three-dimensional printing device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a block diagram showing a control device of the three-dimensional printing device of FIG. 1. [Figure 3] FIG. 2 is a diagram showing the configuration of the inkjet head and its surroundings included in the three-dimensional printing device of FIG. 1. [Figure 4] FIG. 4 is a diagram showing how ink is supplied to a head tank. [Figure 5] FIG. 3 is a diagram illustrating a state in which ink is supplied to an ejection head. [Figure 6]FIG. 2 is a diagram showing how ink is supplied to nozzles of an ejection head. [Figure 7] FIG. 10 is a diagram showing the state when the ejection head is in a printable state. [Figure 8] FIG. 10 is a diagram showing the configuration of the periphery of a conventional ejection head. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0011] FIG. 1 shows a schematic configuration of a three-dimensional printing apparatus 10 according to an embodiment of the present disclosure. The three-dimensional printing apparatus 10 includes a transfer device 20, a first modeling unit 22, a second modeling unit 24, and a control device 28 (see FIG. 2). The transfer device 20, the first modeling unit 22, and the second modeling unit 24 are disposed on a base 29 of the three-dimensional printing apparatus 10. The base 29 has a generally rectangular shape, and in the following description, the longitudinal direction of the base 29 will be referred to as the X-axis direction, the lateral direction of the base 29 as the Y-axis direction, and the direction perpendicular to both the X-axis direction and the Y-axis direction as the Z-axis direction. The Z-axis direction is the same as the vertical direction.

[0012] The transport device 20 includes an X-axis slide mechanism 30 and a Y-axis slide mechanism 32. The X-axis slide mechanism 30 includes an X-axis slide rail 34 and an X-axis slider 36. The X-axis slide rail 34 is disposed on a base 29 so as to extend in the X-axis direction. The X-axis slider 36 is held by the X-axis slide rail 34 so as to be slidable in the X-axis direction. The X-axis slide mechanism 30 also includes an electromagnetic motor 38 (see FIG. 2), and the X-axis slider 36 is moved to any position in the X-axis direction by the drive of the electromagnetic motor 38. The Y-axis slide mechanism 32 also includes a Y-axis slide rail 50 and a table 52. The Y-axis slide rail 50 is disposed on the base 29 so as to extend in the Y-axis direction and is movable in the X-axis direction. One end of the Y-axis slide rail 50 is connected to the X-axis slider 36. The table 52 is held by the Y-axis slide rail 50 so as to be slidable in the Y-axis direction. Furthermore, the Y-axis slide mechanism 32 has an electromagnetic motor 56 (see FIG. 2), and the table 52 moves to any position in the Y-axis direction by driving the electromagnetic motor 56. As a result, the table 52 moves to any position on the base 29 by driving the X-axis slide mechanism 30 and the Y-axis slide mechanism 32.

[0013] Table 52 has a base 60, a holding device 62, and an elevating device 64 (see FIG. 2). Base 60 is formed in a flat plate shape, and a pallet (not shown) is placed on the upper surface. Holding devices 62 are provided on both sides of base 60 in the X-axis direction. Both edges of the pallet in the X-axis direction placed on base 60 are clamped by holding devices 62, thereby fixedly holding the pallet. Furthermore, elevating device 64 is disposed below base 60, and raises and lowers base 60.

[0014] The first modeling unit 22 is a unit that models the wiring of a circuit board and has a first printing unit 72 and a baking unit 74. The first printing unit 72 has an inkjet head 200 (see FIG. 2), which ejects metal ink in a linear pattern. The metal ink is made by dispersing nanometer-sized metal particles, such as silver particles, in a solvent. The surfaces of the metal particles are coated with a dispersant to prevent aggregation in the solvent. The inkjet head 200 ejects the metal ink from multiple nozzles using, for example, a piezoelectric method using piezoelectric elements.

[0015] The baking unit 74 has an infrared irradiation device 78 (see FIG. 2). The infrared irradiation device 78 is a device that irradiates the ejected metal ink with infrared rays, and the metal ink irradiated with infrared rays is baked to form wiring. Note that baking of metal ink is a phenomenon in which, by applying energy, the solvent is evaporated and the protective film on the metal particles, i.e., the dispersant, is decomposed, and the metal particles come into contact or fuse together, thereby increasing the conductivity. Then, by baking the metal ink, metal wiring is formed. Note that hereinafter, metal ink may also be referred to as ink for short.

[0016] The second modeling unit 24 is a unit that models the resin layer of the circuit board, and includes a second printing unit 84 and a curing unit 86. The second printing unit 84 includes an inkjet head 300 (see FIG. 2), which ejects ultraviolet curable resin. The ultraviolet curable resin is a resin that hardens when irradiated with ultraviolet light. The inkjet head 300 may be, for example, a piezo-type inkjet head that uses a piezoelectric element, or a thermal-type inkjet head that heats the resin to generate bubbles and ejects the resin from multiple nozzles.

[0017] The curing unit 86 has a flattening device 90 (see FIG. 2) and an irradiation device 92 (see FIG. 2). The flattening device 90 flattens the upper surface of the ultraviolet curing resin discharged by the inkjet head 300, for example, by leveling the surface of the ultraviolet curing resin and scraping off excess resin with a roller or blade, thereby making the thickness of the ultraviolet curing resin uniform. The irradiation device 92 is equipped with a mercury lamp or LED as a light source, and irradiates the discharged ultraviolet curing resin with ultraviolet light. This hardens the discharged ultraviolet curing resin, forming a resin layer.

[0018] 2, the control device 28 includes a controller 110 and a plurality of drive circuits 112. The plurality of drive circuits 112 are connected to the electromagnetic motors 38, 56, the holding device 62, the lifting device 64, the inkjet head 200, the infrared irradiation device 78, the inkjet head 300, the flattening device 90, and the irradiation device 92. The controller 110 includes a CPU, ROM, RAM, etc., and is mainly a computer, and is connected to the plurality of drive circuits 112. As a result, the operations of the transport device 20, the first modeling unit 22, and the second modeling unit 24 are controlled by the controller 110.

[0019] In the three-dimensional printing device 10, with the above-described configuration, a resin laminate is formed on a pallet placed on the base 60 of the table 52, and wiring is formed on the upper surface of the resin laminate to form a circuit board.

[0020] 3 shows the configuration around the inkjet head 200 of the first printing unit 72. In the configuration of FIG. 3, the same components as those in FIG. 8 are denoted by the same reference numerals.

[0021] 3, an ink flow path 201 is provided in an inkjet head 200. A plurality of nozzles 202 that eject ink in the ink flow path 201 are formed on the bottom surface of the ink flow path 201. Two ends, first and second, 201a and 201b of the ink flow path 201 are connected to a head tank 210 via first and second open / close valves 281 and 282.

[0022] Unlike the head tank 510 of FIG. 8, the head tank 210 is divided into two chambers, a first chamber 211 and a second chamber 212. The first chamber 211 is connected to a first end 201a of the ink flow path 201 via a first opening / closing valve 281, and the second chamber 212 is connected to a second end 201b of the ink flow path 201 via a second opening / closing valve 282. The first chamber 211 is connected to the ink tank 220 via a pipe 230, and a third opening / closing valve 283 is provided at the end of the pipe 230 on the first chamber 211 side. A first pressure line 271 for applying pressure is connected to the first chamber 211. A second pressure line 272 for applying pressure is connected to the second chamber 212.

[0023] A first switching valve 260 that switches the pressure applied to the first chamber 211 via the first pressure line 271 is connected to the end of the first pressure line 271 opposite to the first chamber 211. A third switching valve 264 is connected to the input side of the first switching valve 260 via a third pressure line 273, and a fourth switching valve 266 is connected to the input side of the first switching valve 260 via a fourth pressure line 274. A high negative pressure generated by the vacuum pump 242 and the first pressure regulator 254 and a low negative pressure generated by the vacuum pump 242 and the second pressure regulator 252 are input to the input side of the third switching valve 264. Furthermore, a positive pressure generated by the positive pressure pump 240 and the third pressure regulator 250 and atmospheric pressure are input to the input side of the fourth switching valve 266. Therefore, by appropriately controlling the switching of the first, third and fourth switching valves 260, 264, 266, any one of high negative pressure, low negative pressure, positive pressure and atmospheric pressure can be applied to the first chamber 211.

[0024] A second switching valve 262 that switches the pressure applied to the second chamber 212 via the second pressure line 272 is connected to the end of the second pressure line 272 opposite to the second chamber 212. Similarly to the input side of the first switching valve 260, a third switching valve 264 is connected via a third pressure line 273 to the input side of the second switching valve 262, and a fourth switching valve 266 is connected via a fourth pressure line 274. Therefore, by appropriately controlling the switching of the second to fourth switching valves 262, 264, 266, it is possible to apply any one of high negative pressure, low negative pressure, positive pressure, and atmospheric pressure to the second chamber 212.

[0025] The control process executed by the three-dimensional printing device 10 configured as above will be described in detail with reference to FIGS.

[0026] 4 shows the ink supply process to the head tank 210 executed by the control device 28, particularly the controller 110. When supplying ink C stored in the ink tank 220 to the head tank 210, the controller 110 first controls the first on-off valve 281 to a closed state. Next, the controller 110 controls the third on-off valve 283 to an open state, and controls the first and third switching valves 260, 264 so that a high negative pressure generated by the vacuum pump 242 and the first pressure regulator 254 is supplied to the first pressure line 271 and applied to the first chamber 211 of the head tank 210. As a result, a high negative pressure is applied to the first chamber 211, and the ink C stored in the ink tank 220 flows into the first chamber 211 via the pipe 230.

[0027] 4, arrow A1, which points from the end of the pipe 230 on the first chamber 211 side toward the first chamber 211, indicates the flow of ink C into the first chamber 211. Arrow A2, which points from the first chamber 211 toward the vacuum pump 242, indicates the application of high negative pressure to the first chamber 211. Arrow A3, which points in both directions between the second chamber 212 and the external atmospheric pressure, indicates the application of atmospheric pressure to the second chamber 212. However, at this time, the second on-off valve 282 is controlled to a closed state, and the second chamber 212 does not function when supplying ink C to the first chamber 211. Therefore, positive pressure instead of atmospheric pressure may be applied to the second chamber 212. However, to apply positive pressure, the positive pressure pump 240 must be operated, which would result in unnecessary power consumption, so atmospheric pressure is applied.

[0028] In this way, in the three-dimensional printing apparatus 10, when ink C is supplied from the ink tank 220 to the first chamber 211 of the head tank 210, the pump 520 (see FIG. 8) that was necessary in conventional configurations is no longer necessary, thereby reducing the manufacturing costs of the entire three-dimensional printing apparatus 10. Furthermore, as will be described later with reference to FIGS. 5 to 7, the vacuum pump 242 that generates a high negative pressure is an essential component of the three-dimensional printing apparatus 10 in order to perform other functions, and therefore the vacuum pump 242 is not provided in the three-dimensional printing apparatus 10 solely for the purpose of supplying ink C to the head tank 210. However, in this embodiment, the first pressure regulator 254 is added to generate a high negative pressure, but the cost of adding the first pressure regulator 254 is lower than the cost of adding the pump 520, and therefore the effect of reducing manufacturing costs by eliminating the pump 520 is extremely significant.

[0029] 5 shows how ink C stored in a first chamber 211 of a head tank 210 is filled into the ink flow path 201 of an inkjet head 200 when the ink flow path 201 is empty of ink. Before describing the process of filling the ink flow path 201 with this ink C, we will explain the process of filling the ink flow path 201 with ink C stored in a head tank 510 in the conventional configuration shown in FIG.

[0030] 8, when ink C is stored in the head tank 510, first the third on-off valve 283 is controlled to a closed state. Next, the first and second on-off valves 281, 282 are both controlled to an open state, and the first switching valve 260 is controlled so that positive pressure generated by the positive pressure pump 240 and the third pressure regulator 250 is supplied to the first pressure line 271 and positive pressure is applied to the inside of the head tank 510. As a result, positive pressure is applied to the surface of the ink C in the head tank 510, and the ink C flows into the ink flow path 201 from the first and second ends 201a, 201b of the ink flow path 201.

[0031] Since ink C flows into the ink flow path 201 from a state where there is no ink C, the air in the ink flow path 201 is pushed out from the nozzle 202 by the ink C, but in the process of being pushed out, some of the air becomes bubbles, rises in the ink C, and remains in the ink C. Because bubbles can cause a decrease in print quality, even if the ink flow path 201 is filled with ink C, it is necessary to discharge the ink C from the nozzle 202 to remove the bubbles from the ink flow path 201. This discharged ink C is wasted because it is not used for printing. As such, in the conventional configuration described above, when filling the ink flow path 201 with ink C, ink C is wasted. In this embodiment, it is possible to prevent ink C from being wasted even in this case.

[0032] 5, when ink C is stored in the first chamber 211 of the head tank 210, the controller 110 first controls the third opening / closing valve 283 to a closed state. Next, the controller 110 controls both the first and second opening / closing valves 281, 282 to an open state, and controls the second and third switching valves 262, 264 so that a low negative pressure generated by the vacuum pump 242 and the second pressure regulator 252 is supplied to the second pressure line 272, and a low negative pressure is applied to the second chamber 212 of the head tank 210. Furthermore, the controller 110 controls the first and fourth switching valves 260, 266 so that atmospheric pressure is supplied to the first pressure line 271, and atmospheric pressure is applied to the first chamber 211 of the head tank 210. In this way, the second chamber 212 is placed under a low negative pressure, causing the ink C stored in the first chamber 211 to flow into the ink flow path 201 from the first end 201a of the ink flow path 201. The controller 110 then maintains the low negative pressure state of the second chamber 212 even when the ink flow path 201 is filled with ink C, causing the ink C to flow into the second chamber 212 from the second end 201b of the ink flow path 201. The air in the ink flow path 201 is pushed into the second chamber 212 by the ink C, but air bubbles B remain in the ink C. However, since the air bubbles B rise within the ink C as described above, they burst at the liquid surface of the ink C stored in the second chamber 212 and disappear from the ink C. In this way, the three-dimensional printing device 10 can fill the ink flow path 201 with ink C without any air bubbles.

[0033] 5, the bidirectional arrow A4 between the first chamber 211 and the external atmospheric pressure indicates that atmospheric pressure is being applied to the first chamber 211. The arrow A5 pointing in the direction from the second chamber 212 toward the vacuum pump 242 indicates that a low negative pressure is being applied to the second chamber 211. The arrow A6 pointing in the direction from the first chamber 211 toward the second chamber 212 indicates that ink C flows from the first chamber 211 through the ink flow path 201 into the second chamber 212. When ink C flows from the first chamber 211 through the ink flow path 201 into the second chamber 212, ink C is not supplied into the nozzle 202. This is because the second chamber 212 is under negative pressure.

[0034] 5, when filling the ink flow path 201 with ink C stored in the head tank 510, a low negative pressure is applied to the second chamber 212 of the head tank 210, but this is not limiting and a high negative pressure may be applied instead. The difference between applying a low negative pressure and applying a high negative pressure is whether the speed at which the ink C is filled into the ink flow path 201 is slow or fast, and whichever negative pressure is used will result in the ink C being filled into the ink flow path 201.

[0035] 6 shows how the ink C is filled into the ink flow path 201 without any bubbles, and then the ink C is supplied to the nozzle 202. In FIG. 6, the controller 110 first controls the second and fourth switching valves 262 and 266 so that, from the control state of FIG. 5, the positive pressure generated by the positive pressure pump 240 and the third pressure regulator 250 is supplied to the first pressure line 271, and positive pressure is applied to the first chamber 211 of the head tank 210. Next, the controller 110 controls the first and fourth switching valves 260 and 266 so that the positive pressure generated by the positive pressure pump 240 and the third pressure regulator 250 is supplied to the second pressure line 272, and positive pressure is applied to the second chamber 212 of the head tank 210. As a result, positive pressure is applied to the surfaces of the ink C in the first and second chambers 211 and 212, and the ink C is pushed downward, so that the ink C in the ink flow path 201 is supplied to the nozzle 202.

[0036] 6, arrow A7, which points from the positive pressure pump 240 toward the first chamber 211, indicates a state in which positive pressure is being applied to the first chamber 211. Arrow A8, which points from the positive pressure pump 240 toward the second chamber 212, indicates a state in which positive pressure is being applied to the second chamber 212. Arrows A9, which point from the first and second chambers 211 and 212 toward the ink flow path 201, respectively, indicate a state in which a downward force is being applied to the ink C. Circle C1 extending downward from the nozzle 202 indicates a state in which the nozzle 202 is filled with ink C and some of the ink C1 is dripping from the nozzle 202.

[0037] Fig. 7 shows a state when the control state of Fig. 6 is transitioned to a printable state. In Fig. 7, first, the controller 110 controls the first and third switching valves 260, 264 so that the low negative pressure generated by the vacuum pump 242 and the second pressure regulator 252 is supplied to the first pressure line 271 from the control state of Fig. 6, and the low negative pressure is applied to the first chamber 211 of the head tank 210. Next, the controller 110 controls the second and third switching valves 262, 264 so that the low negative pressure generated by the vacuum pump 242 and the second pressure regulator 252 is supplied to the second pressure line 272, and the low negative pressure is applied to the second chamber 212 of the head tank 210. As a result, a low negative pressure is applied to the surface of the ink C in the first and second chambers 211, 212, and the ink C is pulled upward, so that due to the balance between the upward force acting on the ink C and gravity, the outer surface of the ink C supplied into the nozzle 202 becomes a meniscus, making it ready for printing.

[0038] 7, an arrow A10 pointing in the direction from the first chamber 211 to the vacuum pump 242 indicates a state in which a low negative pressure is applied to the first chamber 211. An arrow A11 pointing in the direction from the second chamber 212 to the vacuum pump 242 indicates a state in which a low negative pressure is applied to the second chamber 212.

[0039] As described above, the three-dimensional printing device 10 of this embodiment includes an inkjet head 200 that ejects ink, a head tank 210 that stores ink to be supplied to the inkjet head 200, an ink tank 220 that stores ink to be supplied into the head tank 210, piping 230 that connects the head tank 210 and the ink tank 220, a vacuum pump 242 that generates a high negative pressure, a first pressure line 271 that connects the head tank 210 and the vacuum pump 242, and a controller 110 that controls the high negative pressure generated by the vacuum pump 242 to be applied to the head tank 210 via the first pressure line 271 when ink is supplied from the ink tank 220 into the head tank 210 via the piping 230.

[0040] In this way, in the three-dimensional printing device 10 of this embodiment, the pump 520 that was necessary in the conventional configuration when supplying ink from the ink tank 220 into the head tank 210 is not required, thereby reducing the overall manufacturing cost of the three-dimensional printing device 10.

[0041] In this embodiment, the inkjet head 200 is an example of an "ejection head." The high negative pressure is an example of a "negative pressure." The vacuum pump 242 is an example of a "negative pressure generator." The controller 110 is an example of a "control unit."

[0042] The head tank 210 is divided into a first chamber 211 and a second chamber 212. The first chamber 211 is connected to the ink tank 220 via a pipe 230, and to a vacuum pump 242 via a first pressure line 271. The first chamber 211 is also connected to a first end 201a of the ink flow path 201 in the inkjet head 200 via a first opening / closing valve 281. When supplying ink from the ink tank 220 to the first chamber 211 in the head tank 210, the controller 110 controls the first opening / closing valve 281 to a closed state, and then controls the first opening / closing valve 281 to apply a high negative pressure to the first chamber 211 of the head tank 210 via the first pressure line 271.

[0043] As a result, even when the head tank 210 is divided into the first chamber 211 and the second chamber 212, the pump 520 that was necessary in the conventional configuration when supplying ink from the ink tank 220 to the first chamber 211 in the head tank 210 is no longer necessary, thereby reducing the overall manufacturing cost of the three-dimensional printing device 10. Incidentally, the first opening / closing valve 281 is an example of a "first opening / closing device."

[0044] The three-dimensional printing apparatus 10 further includes a first switching valve 260 that receives input of high negative pressure and atmospheric pressure, switches between the input high negative pressure and atmospheric pressure, and supplies the input pressure to the first pressure line 271. The second chamber 212 is connected to a vacuum pump 242 via a second pressure line 272 and to a second end of the ink flow path 201 in the inkjet head 200 via a second opening / closing valve 282. A third opening / closing valve 283 is provided in the piping 230 to start or stop the supply of ink from the ink tank 220 to the first chamber 211 of the head tank 210. When ink is supplied from the first chamber 211 in the head tank 210 to the ink flow path 201 of the inkjet head 200, the controller 110 controls the first switching valve 260 so that atmospheric pressure is applied to the first chamber 211 in the head tank 210, and also controls the first switching valve 260 so that a high negative pressure is applied to the second chamber 212 of the head tank 210 via the second pressure line 272.

[0045] This allows ink to be filled into the ink flow path 201 without bubbles, without wasting ink from the inkjet head 200. The first switching valve 260 is an example of a "first switching device." The second opening / closing valve 282 is an example of a "second opening / closing device."

[0046] The three-dimensional printing device 10 further includes a positive pressure pump 240 that generates positive pressure, and a second switching valve 262 that receives input of high negative pressure and positive pressure, switches between the input high negative pressure and positive pressure, and supplies the input to a second pressure line 272. The inkjet head 200 has a plurality of nozzles 202 that eject ink from an ink flow path 201 to the outside, and the first switching valve 260 receives input of the high negative pressure, atmospheric pressure, and also the positive pressure generated by the positive pressure pump 240. When supplying ink from the ink flow path 201 to the plurality of nozzles of the inkjet head 200, the controller 110 controls the first switching valve 260 so that positive pressure is applied to a first chamber 211 of the head tank 210, and also controls the second switching valve 262 so that positive pressure is applied to a second chamber 212 of the head tank 210.

[0047] This allows ink filled in the ink flow path 201 to be supplied to the plurality of nozzles without any bubbles. The positive pressure pump 240 is an example of a "positive pressure generating device."

[0048] The three-dimensional printing apparatus 10 also includes a second pressure regulator 252 that changes the high negative pressure generated by the vacuum pump 242 to a low negative pressure. The low negative pressure changed by the second pressure regulator 252 is input to the first switching valve 260, and the low negative pressure changed by the second pressure regulator 252 is input to the second switching valve 262. When the inkjet head 200 is set to a printable state, the controller 110 controls the first switching valve 260 so that a low negative pressure is applied to the first chamber 211 of the head tank 210, and controls the second switching valve 262 so that a low negative pressure is applied to the second chamber 212 of the head tank 210.

[0049] This makes it possible to print using ink supplied to multiple nozzles without bubbles. The low negative pressure is an example of a "predetermined negative pressure value." The second pressure regulator 252 is an example of a "variation device."

[0050] In addition, when ink is supplied from the first chamber 211 in the head tank 210 to the ink flow path 201 of the inkjet head 200, the controller 110 controls the second switching valve 262 so that a low negative pressure is applied to the second chamber 212 of the head tank 210 instead of a high negative pressure.

[0051] This allows either a high or low negative pressure to be applied to the second chamber 212 of the head tank 210 when ink is supplied from the first chamber 211 in the head tank 210 into the ink flow path 201 of the inkjet head 200, thereby enabling the three-dimensional printing device 10 to be designed more flexibly.

[0052] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0053] (1) In the above embodiment, a metal ink for forming wiring is used as the metal-containing liquid, but various metal-containing liquids containing metal particles can be used. Specifically, for example, a conductive paste in which micrometer-sized metal particles are dispersed in a solvent can be used as the metal-containing liquid.

[0054] (2) In the above embodiment, when ink C stored in the ink tank 220 is supplied to the head tank 210, a high negative pressure is applied to the first chamber 211. However, this is not limiting, and a low negative pressure may be applied. The value of the negative pressure applied to the first chamber 211 varies depending on the relative positions of the ink tank 220 and the head tank 210, etc. When ink C does not easily flow from the ink tank 220 to the head tank 210, a high negative pressure must be applied to the first chamber 211, whereas when ink C easily flows from the ink tank 220 to the head tank 210, a low negative pressure may be applied.

[0055] (3) In the above embodiment, the present invention has been described as being applied to the periphery of the inkjet head 200 of the first printing unit 72. However, this is not limited to this. The periphery of the inkjet head 300 of the second printing unit 84 may also be configured in the same manner as the periphery of the inkjet head 200 of the first printing unit 72, and therefore the present invention may also be applied to the periphery of the inkjet head 300 of the second printing unit 84. [Explanation of symbols]

[0056] 10...3D printing device, 72...first printing unit, 84...second printing unit, 110...controller, 201...ink flow path, 201a...first end, 201b...second end, 202...nozzle, 211...first chamber, 212...second chamber, 200...inkjet head, 210...head tank, 220...ink tank, 230...piping, 240...positive pressure pump, 242...vacuum pump, 250 ...third pressure regulator, 252...second pressure regulator, 254...first pressure regulator, 260...first switching valve, 262...second switching valve, 264...third switching valve, 266...fourth switching valve, 271...first pressure line, 272...second pressure line, 281...first opening / closing valve, 282...second opening / closing valve, 283...third opening / closing valve, C...ink.

Claims

1. an ejection head that ejects ink; a head tank that stores ink to be supplied to the ejection head; an ink tank for storing ink to be supplied to the head tank; a pipe connecting the head tank and the ink tank; a negative pressure generating device that generates a negative pressure; a first pressure line connecting the head tank and the negative pressure generating device; a control unit that controls the negative pressure generated by the negative pressure generating device to be applied to the head tank via the first pressure line when ink is supplied from the ink tank into the head tank via the piping; Equipped with The head tank is divided into a first chamber and a second chamber, the first chamber is connected to the ink tank via the piping, is connected to the negative pressure generating device via the first pressure line, and is further connected to a first end of an ink flow path in the ejection head via a first opening and closing device; When supplying ink from the ink tank to the first chamber in the head tank, the control unit controls the first opening and closing device to a closed state, and then controls the negative pressure to be applied to the first chamber of the head tank via the first pressure line.

2. a first switching device to which the negative pressure and atmospheric pressure are input, and which switches between the input negative pressure and atmospheric pressure and supplies the input negative pressure and atmospheric pressure to the first pressure line; Furthermore, the second chamber is connected to the negative pressure generating device via a second pressure line, and is connected to a second end of the ink flow path in the ejection head via a second opening and closing device; a third opening / closing device that starts or stops the supply of ink from the ink tank to the first chamber of the head tank is provided in the piping; the control unit controls the first switching device so that the atmospheric pressure is applied to the first chamber in the head tank when ink is supplied from the first chamber in the head tank to the ink flow path of the ejection head, and controls the first switching device so that the negative pressure is applied to the second chamber of the head tank via the second pressure line. The three-dimensional printing device of claim 1 .

3. a positive pressure generating device that generates positive pressure; a second switching device to which the negative pressure and the positive pressure are input, and which switches between the input negative pressure and the input positive pressure and supplies the pressure to the second pressure line; Furthermore, the ejection head has a plurality of nozzles that eject ink from the ink flow path to the outside, the positive pressure generated by the positive pressure generating device is input to the first switching device in addition to the negative pressure and the atmospheric pressure, when ink in the ink flow path is supplied to the plurality of nozzles of the ejection head, the control unit controls the first switching device so that the positive pressure is applied to the first chamber of the head tank, and controls the second switching device so that the positive pressure is also applied to the second chamber of the head tank. The three-dimensional printing device of claim 2 .

4. A fluctuating device that fluctuates the negative pressure generated by the negative pressure generating device to a predetermined negative pressure value. Furthermore, The first switching device receives the predetermined negative pressure value varied by the variation device, The second switching device receives the predetermined negative pressure value varied by the variation device, When the control unit puts the ejection head into a printable state, the control unit controls the first switching device so that the predetermined negative pressure value is applied to the first chamber of the head tank, and controls the second switching device so that the predetermined negative pressure value is applied to the second chamber of the head tank. The three-dimensional printing device of claim 3 .

Images