Ink supply system

Abstract

The ink supply system includes: a tank for storing ink; an ink supply path for supplying ink from the tank to the inkjet head; an ink return path that returns the ink from the inkjet head to the tank; a pump provided in the ink return path; and a damper provided in the ink return path between the inkjet head and the pump, the damper including: a reservoir chamber for storing the ink; and a telescopic member that is in contact with at least the ink stored in the storage chamber.

Description

Technical Field

[0001] The present disclosure relates to an ink supply system for supplying ink to an inkjet device. Background Art

[0002] An inkjet device is a device that prints or draws on a printed surface by ejecting ink from an inkjet head. The inkjet head is provided with a plurality of fine nozzles. The nozzles that eject ink are selected according to the pattern drawn on the printed surface.

[0003] The inkjet device includes an inkjet head and an ink supply system for supplying ink to the inkjet head. The ink supply system is described in Patent Document 1 and the like. The ink supply system described in Patent Document 1 has an ink circulation path and is an ink circulation type ink supply system for circulating ink between an ink tank and an inkjet head. The ink circulation type ink supply system has the advantage of being able to suppress clogging of the nozzle of the inkjet head caused by drying of the ink because the ink does not remain in the inkjet head.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-157362 Summary of the invention

[0007] In one embodiment of the ink supply system of the present invention, the ink supply system includes: a tank for storing ink; an ink supply path for supplying ink from the tank to an inkjet head; an ink return path for returning ink from the inkjet head to the tank; a pump disposed in the ink return path; and a damper disposed in the ink return path between the inkjet head and the pump, the damper including: a storage chamber for storing the ink; and a telescopic member in contact with at least the ink stored in the storage chamber.

[0008] In one embodiment of the ink supply system disclosed herein, the ink supply system comprises: a tank for storing ink; an ink circulation path for connecting the tank and an inkjet head so that the ink circulates between the tank and the inkjet head; and a pump provided in the ink circulation path, and at least two or more components provided in the ink circulation path are integrated.

[0009] In one embodiment of the ink supply system of the present invention, the ink supply system includes: a tank for storing ink; and a degassing tube, which is arranged in the tank and degases the gas in the ink, and the degassing tube includes a tube at least part of which is arranged in the ink and the pressure in the tube is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1It is a flow path system diagram of the ink supply system according to the embodiment.

[0011] Figure 2 It is a perspective view showing assembly blocks of the ink supply system.

[0012] Figure 3 This is a flow path system diagram of a conventional ink supply system.

[0013] Figure 4 This is a perspective view showing assembly blocks of a conventional ink supply system.

[0014] Figure 5 It is a plan view showing the arrangement position of a conventional ink supply system.

[0015] Figure 6 It is a perspective view showing the arrangement position of a conventional ink supply system.

[0016] Figure 7 It is a plan view showing the arrangement position of the ink supply system according to the embodiment.

[0017] Figure 8 It is a perspective view showing the arrangement position of the ink supply system according to the embodiment.

[0018] Fig. 9 This is a diagram showing the relationship among a conventional head, a pump, and a tank.

[0019] Fig.10 It is a diagram showing the relationship among the head, the pump, and the tank according to the embodiment.

[0020] Fig.11 This is a diagram showing an example in which two low-output pumps are connected in series.

[0021] Fig.12 It is a cross-sectional view showing the structure of the damper according to the embodiment.

[0022] Fig.13 This is a diagram showing a conventional configuration example using a can-type air damper.

[0023] Fig.14 It is a figure which shows the connection state of the tank in embodiment.

[0024] Fig.15 It is a figure which shows the state of connection of a conventional tank.

[0025] Fig.16 It is a cross-sectional view showing the condition inside the tank.

[0026] Fig.17 This is a diagram for explaining a conventional degassing module.

[0027] Fig.18It is a cross-sectional view showing the structure of the tank according to the embodiment.

[0028] Fig.19 It is a cross-sectional view showing a structural example of a conventional tank.

[0029] Fig. 20 It is a cross-sectional view showing a structural example of a conventional tank.

[0030] Fig.21 It is a diagram showing a mounted state of a pressure sensor according to an embodiment.

[0031] Fig. 22 It is a diagram showing a mounting state of a conventional pressure sensor. DETAILED DESCRIPTION

[0032] Since the ink used in the inkjet device is mostly very expensive, it is required to suppress the amount of ink required for the ink supply system. In addition, in the initial stage of the development of the inkjet device, since the ink used therein is also under development, it is necessary to further suppress the amount of ink required for the ink supply system.

[0033] However, in the conventional ink circulation type ink supply system, the ink circulation path tends to be longer, so the required amount of ink tends to be larger. In order to reduce the amount of ink required for the ink circulation type ink supply system, it is considered effective to miniaturize the ink supply system itself.

[0034] The miniaturization of the ink supply system has various advantages, such as reducing the amount of ink and increasing the degree of freedom in the arrangement position of the ink supply system.

[0035] The present disclosure has been made in consideration of the above aspects, and provides a compact ink supply system.

[0036] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0037] <1> Overall structure of ink supply system

[0038] Figure 1 is a flow path system diagram of the ink supply system 100 according to the embodiment, Figure 2 1 is a perspective view showing assembly blocks of the ink supply system 100 .

[0039] Depend on Figure 1 As can be seen, the ink supply system 100 is connected to an inkjet head (hereinafter simply referred to as a “head”) 10 , and supplies ink to the head 10 .

[0040] The ink supply system 100 includes a tank 110 storing ink 1 and an ink circulation path 120 . The ink supply system 100 is an ink circulation type ink supply system that circulates the ink 1 between the tank 110 and the head 10 through the ink circulation path 120 .

[0041] The ink circulation path 120 includes an ink supply path for supplying the ink 1 in the tank 110 to the head 10, and an ink return path for returning the remaining ink 1 not ejected by the head 10 to the tank 110. That is, when the ink 1 is supplied to the head 10 via the ink supply path of the ink circulation path 120, the ink is ejected from the nozzle (not shown) of the head 10 according to the ejection signal, and the remaining ink 1 not ejected is returned to the tank 110 again via the ink return path of the ink circulation path 120.

[0042] The ink circulation path 120 is provided with a pump (P) 130 . The pump 130 pressurizes the ink 1 in the ink circulation path 120 , thereby causing the ink 1 to flow in the ink circulation path 120 in the direction of arrow A1 in the figure.

[0043] In addition, valves 141, 142, 143, and 144, a filter 150, and the like are provided in the ink circulation path 120. The filter 150 removes unnecessary particles and the like contained in the ink 1.

[0044] Furthermore, the ink circulation path 120 is connected to pressure sensors (PS) 161 , 162 , and 163 .

[0045] The pressure sensor 161 detects the pressure of the ink supply path, and the pressure sensor 162 detects the pressure of the ink return path. The pressure detection signals S1 and S2 detected by the pressure sensors 161 and 162 are output to the control unit 170. The control unit 170 outputs a control signal S3 to the pump 130 based on the pressure detection signals S1 and S2. As a result, the flow rate of the ink 1 flowing through the head 10 is controlled to a desired value. In addition, the pressure of the pressure control unit 180 is adjusted based on the pressure detection signals S1 and S2 of the pressure sensors 161 and 162, thereby adjusting the absolute value of the pressure (in other words, the pressure inside the head) so that the ink 1 does not droop from the nozzle surface of the head 10.

[0046] The pressure sensor 163 detects the pressure in the tank 110. The pressure detection result detected by the pressure sensor 163 is sent to the pressure control unit 180. The pressure control unit 180 calculates the appropriate pressure in the tank based on the pressure detection signals S1 and S2 of the pressure sensors 161 and 162, and controls the pressure in the tank 110 to a desired value by sending air into the tank 110 or exhausting the air. Thus, as described above, the absolute value of the pressure (in other words, the head internal pressure) is adjusted so that the ink 1 does not droop from the nozzle surface of the head 10.

[0047] When ink 1 is replenished to the ink supply system 100 , ink 1 is sent from the external tank 190 to the ink circulation path 120 via the valve 143 . On the other hand, when ink 1 is discharged from the ink supply system 100 , ink 1 is sent to the external tank 190 via the valve 143 .

[0048] In addition to such a structure, the ink supply system 100 of this embodiment further includes a damper 200 in the ink circulation path 120 between the head 10 and the pump 130. The damper 200 suppresses the pulsation of the ink 1 generated by the pump 130. Thus, since the pulsation of the ink 1 can be suppressed by a simple structure, the ink supply system 100 can be miniaturized. The detailed structure of the damper 200 and the detailed effects based on the damper 200 will be described in detail later.

[0049] In addition, the ink supply system 100 of the present embodiment includes a degassing tube 300 in the tank 110. The degassing tube 300 is connected to a decompression pump 310. In the present embodiment, a vacuum pump is used as the decompression pump 310.

[0050] The degassing tube 300 is provided at a position immersed in the ink 1 in the tank 110. The degassing tube 300 is depressurized by the decompression pump 310, so that the dissolved gas in the ink 1 is introduced into the degassing tube 300. Thus, the ink 1 can be degassed. In addition, a trap 320 is provided between the degassing tube 300 and the decompression pump 310, and the ink 1 introduced into the degassing tube 300 is captured by the trap 320. By providing the trap 320, a failure of the degassing function can be detected. The following will be described in detail. Basically, the ink 1 will not be introduced into the degassing tube 300. When the degassing tube 300 is damaged, the ink 1 is introduced into the degassing tube 300. In the present embodiment, when the ink 1 is detected by the trap 320, it is determined that the degassing function has failed. In addition, by providing the trap 320, when the degassing tube 300 is damaged, the ink 1 will not flow to the decompression pump 310, so that the decompression pump 310 can also be protected.

[0051] <2> Manifold

[0052] The ink supply system 100 of the present embodiment reduces the number of joints between components by manifolding the components (or in other words, integrating the components).

[0053] exist Figure 1 In the example of , the filter 150, the tank 110, and the valve 141 are manifolded to form a first unit 100-1. In addition, the valve 142, the damper 200, the pump 130, and the valves 143 and 144 are manifolded to form a second unit 100-2.

[0054] Here, not all components are manifolded, but divided into the first unit 100-1 and the second unit 100-2 to ensure maintainability of the filter 150. However, when a filter 150 that does not require maintenance or maintenance that does not require removal is used, the manifold may be formed without being divided into the first unit 100-1 and the second unit 100-2.

[0055] Figure 1 The solid circles in the figure represent joints. Figure 1 The corresponding parts are marked with the same symbols. Figure 2 In the drawings, reference symbol "J" represents a joint.

[0056] Figure 3 It is a flow path system diagram of a conventional ink supply system 100 a as a comparative example. Figure 4 1 is a perspective view showing an assembly block of a conventional ink supply system 100a as a comparative example. Figure 3 In, with Figure 1 The same numbers are used for parts with the same names and followed by an "a". Figure 3 In addition to Figure 1 In addition to the components, a needle valve 101a, an air damper (AD) 102a, a flow meter (F) 103a, a degassing module 104a, a pump 105a, etc. are provided, but these are known structures and thus description thereof is omitted here.

[0057] Figure 3 The solid circles in the figure represent joints. Figure 4 In the drawings, reference symbol "J" represents a joint.

[0058] right Figure 1 and Figure 3 , Figure 2 and Figure 4 As can be seen from the comparison, the ink supply system 100 of the present embodiment significantly reduces the number of joints by manifolding compared to the conventional ink supply system 100 a .

[0059] In the present embodiment, the ink supply system 100 can be unitized and miniaturized by manifolding, and thus the ink supply system 100 can be arranged near the head 10 .

[0060] Figure 5 as well as Figure 6 1 and 2 are a plan view and a perspective view respectively showing the arrangement position of the conventional ink supply system 100a. Figure 7 as well as Figure 8 They are respectively a plan view and a perspective view showing the arrangement position of the ink supply system 100 according to the present embodiment.

[0061] Depend on Figure 5 as well as Figure 6 It can be seen that the conventional ink supply system 100a is arranged at a position separated upward (in the +Z direction) from the head 10. Figure 7 as well as Figure 8 It can be seen that the ink supply system 100 of the present embodiment is arranged near the head 10 .

[0062] Thus, the length of the piping from the ink supply system 100 of the present embodiment to the head 10 is shorter, and accordingly, the amount of ink required is reduced. For example, when the inner diameter of the piping is 2 mm, the conventional piping length is 4 m, and the piping length of the embodiment is 1 m, the amount of ink 1 used can be reduced by about 10 mL.

[0063] In addition, in the configuration of this embodiment ( Figure 7 as well as Figure 8 ), compared with the previous configuration ( Figure 5 as well as Figure 6 ), the height difference between the head 10 and the pump 130 is reduced, so the recovery rate of the ink 1 in the units 100-1 and 100-2 of the ink supply system 100 is improved. For example, the ink recovery rate in the past was 80%, while the ink recovery rate in this embodiment is 95%.

[0064] Here, the reason why it is difficult to bring the conventional ink supply system 100 a close to the head 10 will be described.

[0065] The first reason is that since a plurality of heads 10 are arranged closely around the head unit 10X, there is no space for mounting an ink supply system 100a of a conventional size. In addition, since the ejection of ink from the head 10 requires ultra-high precision, it is not preferable to arrange a heavy ink supply system 100a near the head 10 as in the past.

[0066] The second reason is that the conventional ink supply system 100 a has many pipes, and therefore it is difficult to access the head unit 10X which is a movable part.

[0067] In this embodiment, the ink supply system 100 can be miniaturized and lightweight by manifolding, so the first reason can be overcome. For example, by miniaturization and lightweighting of this embodiment, the weight of the ink supply system 100 is reduced from 10 kg to 3 kg. In addition, by manifolding, the amount of piping is reduced, so the second reason can be overcome.

[0068] In addition, Figure 1In the example, the filter 150, the tank 110 and the valve 141 are manifolded to form the first unit 100-1, and the valve 142, the damper 200, the pump 130 and the valves 143 and 144 are manifolded to form the second unit 100-2, but the manifolded units are not limited to this. In short, as long as at least two or more components are manifolded, the number of joints can be reduced. Of course, the more the number of manifolded components is increased, the more the number of joints can be reduced.

[0069] Here, at least two or more components that are the object of manifolding refer to components that are arranged with the ink circulation path 120 sandwiched therebetween. The manifolding of the present disclosure refers to manifolding of components that are arranged with the ink circulation path 120 sandwiched therebetween including the ink circulation path 120. More specifically, at least two or more components that are the object of manifolding refer to, for example, two or more of the filter 150, the tank 110, and the valve 141. In addition, at least two or more components that are the object of manifolding refer to, for example, two or more of the valve 142, the damper 200, the pump 130, and the valves 143 and 144.

[0070] It is worth mentioning that the effect of shortening the ink circulation path 120 by reducing one joint is small, and therefore the effect of reducing the ink 1 is also small. However, since the ink 1 is very expensive, even if one joint is reduced, the effect caused by it is large.

[0071] Furthermore, by reducing the number of joints, the inside of the units 100 - 1 and 100 - 2 can be easily set to an empty state without the ink 1 , thereby improving the maintainability.

[0072] Furthermore, by forming a manifold, the resistance of the ink circulation path 120 can be reduced, and as a result, a low-output pump 130 can be used, thereby reducing pulsation. It is worth mentioning that it is difficult to use a low-output pump in the past for the following reasons.

[0073] The first reason is that the pressure loss in the ink circulation path 120 is large, and it is difficult for a low-output pump to circulate the ink 1 .

[0074] Reason 2: Since the intake pressure of a low-output pump is weak, it is difficult to fill the low-output pump with ink.

[0075] In the ink supply system 100 of the present embodiment, the number of joints is reduced by manifolding, and the flow path length is shortened, so the above-mentioned reason 1 can be overcome.

[0076] Depend on Figure 5 Previous configuration and Figure 7It can also be known from the configuration of the present embodiment that, in the present embodiment, since a small ink supply system 100 can be realized by manifolding, the ink supply system 100 can be arranged near the head 10. Therefore, since the height difference between the head 10 and the tank 110 can be reduced, a low-output pump with a weaker inlet pressure can be applied. In the conventional ink supply system, for example, a pump with a suction pressure of 30 kPa and a discharge pressure of 600 kPa is required, but in the ink supply system 100 of the present embodiment, for example, a low-output pump with a suction pressure of 1 kPa and a discharge pressure of 25 kPa can be applied. As a result, the above-mentioned reason 2 can be overcome.

[0077] Specifically, use Fig. 9 as well as Fig.10 to explain. Fig. 9 1 is a diagram showing the relationship among the conventional head 10 , the pump 130 a , and the tank 110 a . Fig.10 1 is a diagram showing the relationship among the head 10, the pump 130, and the tank 110 of the present embodiment. Fig. 9 In the conventional relationship shown, the height difference between the head 10 and the tank 110a is large, so it is difficult to adopt a low-output pump as the pump 130a.

[0078] In contrast, Fig.10 In the embodiment shown in FIG. 1 , the height difference between the head 10 and the tank 110 is small, so a low-output pump can be used as the pump 130. Furthermore, in the embodiment, as shown in FIG. Fig.11 As shown, two or more low-output pumps 130-1 and 130-2 may be connected in series. Thus, according to the manifolded ink supply system 100 in this embodiment, a low-output pump can be used, so the pulsation of the ink 1 can be suppressed, and as a result, the deviation of the ink ejection amount at the nozzle of the head 10 caused by the pulsation of the ink 1 can be suppressed.

[0079] <3> Damper

[0080] Fig.12 It is a cross-sectional view showing the structure of the damper 200 according to the present embodiment.

[0081] The damper 200 has a main body 210 made of metal such as stainless steel. The main body 210 has a storage space 211 for the ink 1 and ink flow paths 212 and 213 connected to the storage space 211 formed by cutting, for example. The ink flow paths 212 and 213 communicate with the ink circulation path 120 .

[0082] In addition, the damper 200 is provided with a stretchable sheet 220 so as to cover the opening of the storage space 211. In the case of this embodiment, the sheet 220 is a PTFE (polytetrafluoroethylene) film. In addition, the sheet 220 is not limited to this, and any sheet material can be used as long as it is stretchable and inert to the ink 1.

[0083] In the damper 200, when the pulsation of the ink 1 occurs in the ink circulation path 120, the ink 1 enters and exits the storage space 211 via the ink flow paths 212 and 213, and the sheet 220 repeatedly becomes an extended state or an original contracted state indicated by a single dotted line in the figure according to the pulsation. As a result, the pulsation of the ink 1 is attenuated. Therefore, even if the pulsation is generated in the ink 1 by the pump 130, the pulsation is attenuated by the damper 200, so that the deviation of the ink ejection amount at the nozzle of the head 10 can be suppressed.

[0084] In addition, for example, Figure 3 In the conventional ink supply system 100a shown in FIG. 1 , a structure using, for example, a tank-type air damper 102a between the pump 130a and the head 10 or a structure in which the length of the piping to the head 10 is extended is used to suppress the pulsation of the ink generated by the pump 130a from being transmitted to the head 10. However, no matter which structure is used, a large amount of ink is required. In particular, when the structure using the air damper 102a is used, the filling amount of the ink is difficult to control, and substantially the same amount of ink as the tank is required.

[0085] Fig.13 FIG. 2 is a diagram showing a conventional structural example using a can-type air damper. Fig.13 In the structural example, the ink inlet side of the head 10 is connected to the input tank (IN tank) a1, and the ink outlet side of the head 10 is connected to the output tank (OUT tank) a2, and a buffer tank a3 is connected between the input tank a1 and the output tank a2. The remaining ink in the input tank a1 and the output tank a3 is sent to the buffer tank a3 by pumps a4 and a5. The ink in the buffer tank a3 is sent to the input tank a1 by pump a6. The pressures in the input tank a1, the output tank a2, and the buffer tank a3 are independently controlled by the pressure control unit a7. As a result, the ink in the input tank a1 is supplied to the head 10 according to the pressure difference between the input tank a1 and the output tank a2. Fig.13 In such a structure, there is no pump between the head 10 and the tank, so the pulsation caused by the pump is not transmitted to the head 10 .

[0086] However, in Fig.13 In such a conventional structure, it is necessary to use a plurality of tanks, so the structure becomes larger and the amount of ink required increases.

[0087] In contrast, according to the structure using the damper 200 of this embodiment, the damper size is smaller than that of the conventional structure, so the required amount of ink can be reduced. In addition, pulsation can be attenuated without using multiple tanks, so a single tank can be achieved.

[0088] Fig.14 as well as Fig.15 2 is a diagram showing the difference between the tank of the present embodiment and the tank of the prior art in an easy-to-understand manner. Fig.14 As shown, since the damper 200 is provided, only a single tank 110 is required. In contrast, in the conventional structure, in order to prevent the pulsation of the pump from being transmitted to the head 10, tanks 110 and 110a need to be provided on both sides of the pump 130. In addition, 110a indicates a buffer tank.

[0089] In addition, a single tank 110 is described in the embodiment, but the single tank 110 does not mean Fig.15 Alternatively, one ink supply system 100 may include a tank 110 of R color, another ink supply system 100 may include a tank 110 of G color, and another ink supply system 100 may include a tank 110 of B color, and the inkjet device may include three ink supply systems 100 of three colors. Alternatively, one ink supply system 100 may include tanks 110 of R, G, and B colors, and these tanks 110 may be switched to be connected to the head 10.

[0090] In any case, the damper 200 only needs to include a storage chamber for storing ink and a retractable member that at least contacts the ink stored in the storage chamber. In this way, the same effects as those described above can be obtained.

[0091] <4> Degassing module

[0092] Fig.16 1 is a cross-sectional view showing the state inside the tank 110. A degassing tube 300 is provided inside the tank 110. The degassing tube 300 is provided at a position immersed in the ink 1. The degassing tube 300 is preferably arranged so as to be immersed in the ink 1 as much as possible. Fig.16 It can also be seen that the degassing pipe 300 is configured to extend almost entirely in the vertical direction of the tank 110. Fig.16 In the example of FIG. 1 , the degassing tube 300 is folded back and forth once in the vertical direction. However, the area in contact with the ink 1 may be further increased by folding back and forth twice or more.

[0093] The degassing tube 300 is formed using a material that allows gas to pass therethrough but does not allow liquid to pass therethrough, such as a hollow fiber.

[0094] With such a configuration, the ink 1 can be degassed without increasing the amount of ink, and thus the amount of ink required for the ink supply system 100 can be reduced compared to the related art.

[0095] Here, a conventional degassing module is described as a comparative example. Figure 3 Corresponding parts are marked with the same symbols. Fig.17 The degassing module used in the conventional ink supply system 100a allows ink to pass through a degassing tube 104a1 and degases the ink by evacuating a box 106a in which the degassing tube 104a1 is placed.

[0096] In the structure of this embodiment, Fig.17 Compared with the conventional structure shown in FIG. 1 , degassing is performed in the tank 110, so there is no need Fig.17 As a result of the special path for degassing shown, the amount of ink can be reduced.

[0097] Furthermore, in the configuration of the present embodiment, the pressure-reducing pump 310 can be disposed outside the ink supply system 100 , and therefore deaeration can be performed without complicating the configuration of the ink supply system 100 .

[0098] It is worth mentioning that when the structure of this embodiment is applied, the air in the tank 110 is also degassed through the degassing pipe 300, and the pressure in the tank 110 is gradually reduced, but the pressure in the tank 110 is prevented from changing by the pressure control unit 180. The pressure in the tank 110 is controlled to be constant so as to become the desired pressure required by the control unit 170.

[0099] <5> Flow calculation

[0100] In order to eject the ink 1 from the head 10 well, it is required to optimize the flow rate of the ink flowing through the ink circulation path 120. Figure 3 As shown, conventionally, a flow meter 103a is required.

[0101] A method of calculating the flow rate from the differential pressure in the ink circulation path 120 is also conceivable, but it is difficult to calculate the flow rate from the differential pressure because the flow path resistance of the head 10 is unknown. In fact, since the flow path in the head 10 is complex, the difference between the design value and the actual object is large, and it is difficult to calculate the correct flow path resistance from the design value.

[0102] In addition, the conventional ink supply system 100a has many joints and many parts connected by pipes, so the pipe length varies depending on the construction method, and the flow resistance changes. In contrast, the ink supply system 100 of this embodiment is manifolded, so the change of flow resistance is small.

[0103] Considering this aspect, in the present embodiment, during the device startup phase of the ink supply system 100, for example, a flow meter clamped outside the pipe is used to measure the flow rate, and the differential pressure between the pressure sensors 161 and 162 is recorded to calculate the flow path resistance. Then, the flow rate is calculated based on the calculated flow path resistance and the differential pressure. In this way, the flow meter 103a ( Figure 3 ). In addition, the calculation and recording of the differential pressure, the calculation of the flow path resistance, and the calculation of the flow rate can be performed in the control unit 170, for example.

[0104] In addition, in the inkjet device, the user sometimes changes the ink used when the device is started. When the ink is changed, the viscosity changes, and the ease of flow changes, so it is impossible to measure the correct flow rate under the conditions when the device is started. In this embodiment, when the ink is changed, the viscosity of the changed ink is input to the control unit 170 of the ink supply system 100. The control unit 170 corrects the relationship between the differential pressure and the flow rate based on the viscosity of the changed ink, thereby being able to measure the flow rate without re-adjusting the flow rate.

[0105] <6> Can

[0106] Next, the detailed structure of the tank according to the present embodiment will be described.

[0107] Fig.18 is a cross-sectional view showing the structure of the tank 110 .

[0108] The lower portion of the tank 110 is connected to one end of the ink supply path connecting the tank 110 and the ink inlet of the head 10 in the ink circulation path 120. In addition, the upper portion of the tank 110 is connected to one end of the ink return path connecting the ink outlet of the head 10 and the tank 110 in the ink circulation path 120.

[0109] A throttle portion 110-1 is formed at the lower portion of the tank 110, which narrows as it goes downward. One end of the ink supply path is connected to the throttle portion 110-1. The throttle portion 110-1 has an inclined surface 110-2, which functions to concentrate the ink 1 in the tank 110 to the ink supply path. In the example of this embodiment, the throttle portion 110-1 is funnel-shaped.

[0110] One end of the ink return path is connected to a position above the throttle portion 110 - 1 and along the wall surface of the tank 110 . Thus, the ink 1 returned from the head 10 is stored in the tank 110 from the top along the wall surface of the tank 110 .

[0111] With such a structure, according to the tank 110 of this embodiment, the flow of the ink 1 in the tank 110 is unidirectional, so stagnation is reduced and the required amount of ink is reduced. As a result, particle sedimentation is suppressed, and the degassing effect by the degassing tube 300 is improved, which has the effect of further reducing the amount of ink in the tank 110.

[0112] Here, as a comparative example, Fig.19 as well as Fig. 20 FIG. 1 shows a structural example of a conventional tank 110a. Fig.19 As can be seen from the example, conventionally, the bottom of the tank 110a is flat, and the bottom of the tank 110a is provided with an inlet and outlet 110a-1 for the ink 1. In contrast, the tank 110 of this embodiment forms a throttle portion 110-1 at the lower portion of the tank 110, and the ink 1 flows into the tank 110 from the upper portion, and the ink 1 flows out of the tank 110 from the throttle portion 110-1 at the lower portion.

[0113] Conventionally, it has been difficult to adopt a structure that unidirectionalizes the flow in the tank for the following reasons.

[0114] Reason 1: Fig. 20 As shown, when the ink 1 drops from the upper portion of the tank 110a, the liquid surface shakes, and there is a concern that the stability of the liquid surface may deteriorate and bubbles may be generated.

[0115] Reason 2: When the ink 1 drips from above, there is a concern that the liquid level sensors 110a-2 and 110a-3 may erroneously respond.

[0116] The third reason: Since there are many paths connected to the tank 110a, a plurality of joints are required at the bottom of the tank 110a, and therefore it is difficult to form an inclined surface at the bottom of the tank 110a.

[0117] Reason 4: It is difficult to perform sharp-angle processing on the bottom of the tank 110a.

[0118] In this embodiment, the first reason is overcome by making the ink 1 entering the tank 110 fall along the wall. In addition, electrostatic capacitance sensors are selected as the liquid level sensors 110-3 and 110-4, and the liquid level sensors 110-3 and 110-4 are arranged on the side opposite to the wall along which the ink 1 falls, and further, the sensitivity is adjusted to avoid erroneous response, thereby overcoming the second reason.

[0119] In addition, the degassing tube 300 is built into the tank 110 and the tank is made into a single tank, thereby minimizing the path and setting the tank bottom as a single path. In this way, the third reason mentioned above can be overcome. In addition, it is also possible to set the path out of the tank 110 as one, and divide it into the path of the degassing device after the ink 1 comes out of the tank 110, but a pump is arranged in the path of the degassing device. Therefore, if the path is branched after coming out of the tank 110, the pulsation will be transmitted to the head 10, which is not preferred.

[0120] In addition, the fourth reason can be overcome by processing the sharp angle of the can bottom by processing the conventional drill tip of 120 degrees to 90 degrees.

[0121] As described above, according to the tank 110 of this embodiment, the following effects can be obtained.

[0122] The stagnation elimination due to the unidirectionalization of the flow in the tank 110 allows the ink in contact with the degassing tube 300 to circulate at all times, thereby improving the degassing effect by the degassing tube 300. In addition, the sedimentation of particles is suppressed.

[0123] By making the bottom of the tank sharp, it is possible to physically prevent the particles in the tank, where the flow velocity is substantially the slowest, from settling.

[0124] Since the diameter at the tank outlet is reduced, the amount of ink at the time of the response of the liquid level sensor 110 - 3 for empty detection is reduced, and the minimum amount of ink required for ink circulation can be reduced.

[0125] <7> Pressure Sensors

[0126] Fig.21 is a diagram showing a mounted state of the pressure sensor 161 ( 162 ) according to the present embodiment. Fig. 22 This is a diagram showing a mounting state of a conventional pressure sensor 161 ( 162 ).

[0127] like Fig.21 In this way, the pressure sensor 161 (162) of this embodiment is installed vertically upward on the ink circulation path 120. In other words, the pressure sensor 161 (162) is connected to the upper part of the pipeline of the ink circulation path 120. As a result, the stagnation in the ink circulation path 120 is reduced, and the sedimentation of particles in the ink circulation path 120 is suppressed.

[0128] In the past, Fig. 22 As shown, in order to fill the pressure sensor 161 (162) with ink 1, the pressure sensor 161 (162) is mounted downward or sideways. However, the ink does not circulate inside the pressure sensor 161 (162), so it becomes a stagnant part.

[0129] In this embodiment, if Fig.21 Thus, by installing the pressure sensor 161 (162) vertically upward, stagnation can be reduced. The following describes the reasons why it is difficult to realize this structure in the past.

[0130] Reason 1: When the pressure sensor 161 (162) is installed vertically upward, if the ink 1 contains bubbles, foam clogging occurs, making it difficult to fill the pressure sensor 161 (162) with the ink 1. Foam clogging refers to the occurrence of unexpected bubbles in a portion that should be filled with liquid, and the bubbles remain.

[0131] Second reason: When the pressure sensor 161 ( 162 ) is mounted vertically upward, if air exists in the pressure sensor 161 ( 162 ), an error occurs in the measurement value of the pressure sensor 161 ( 162 ).

[0132] In this embodiment, the degassing module 300 is provided in the tank 110, and the ink 1 is degassed, so the first reason mentioned above can be overcome. In addition, in this embodiment, the joints are reduced by manifolding, so the pressure receiving surface of the pressure sensor 161 (162) can be brought close to the height of the flow path. Thus, the second reason mentioned above can be overcome.

[0133] <8> Summarize

[0134] As described above, the ink supply system 100 of the present embodiment comprises: a tank 110 storing ink 1; an ink circulation path 120 connecting the tank 110 and the head 10 so that the ink 1 circulates between the tank 110 and the head 10; a pump 130 disposed in the ink circulation path 120 on the downstream side of the head 10; and a damper 200 disposed in the ink circulation path 120 between the head 10 and the pump 130, absorbing the pulsation of the ink 1 by expanding and contracting the sheet 220.

[0135] Thus, compared with the conventional structure, the damper size can be reduced, and the amount of ink can be reduced. In addition, the pulsation can be attenuated even without using multiple tanks, so a single tank can be realized. Therefore, a small ink supply system 100 can be realized.

[0136] In addition, the ink supply system 100 of the present embodiment includes: a tank 110 for storing ink 1; an ink circulation path 120 for connecting the tank 110 and the head 10 so that the ink 1 circulates between the tank 110 and the head 10; and a pump 130, which is arranged in the ink circulation path 120 on the downstream side of the head 10, and at least two or more components arranged in the ink circulation path 120 are integrated (which can also be called manifolding).

[0137] This can reduce the length of the joint and the path, thereby realizing a compact ink supply system 100 .

[0138] The ink supply system 100 of this embodiment includes a tank 110 storing the ink 1 and a degassing tube 300 provided at a position immersed in the ink 1 in the tank 110 . The inside of the tube is depressurized by a decompression pump 310 , thereby degassing the gas in the ink 1 .

[0139] Thus, since deaeration is performed in the tank 110 , a special path for deaeration is not required, and as a result, a compact ink supply system 100 can be realized, and the amount of ink can be reduced.

[0140] The above-mentioned embodiment is only an example of a specific implementation of the present invention, and the technical scope of the present invention should not be interpreted in a limiting manner. That is, the present invention can be implemented in various forms within the scope of its gist or its main features.

[0141] Industrial Applicability

[0142] The technology disclosed herein is suitable for an ink circulation type ink supply system that supplies ink to an inkjet device.

[0143] Explanation of symbols

[0144] 1 Ink

[0145] 10 heads (inkjet heads)

[0146] 10X Head Unit

[0147] 100, 100a Ink supply system

[0148] 100-1 Unit 1

[0149] 100-2 Unit 2

[0150] 110, 110a, 190 cans

[0151] 110-1 Throttling Unit

[0152] 110-2 Inclined surface

[0153] 110-3, 110-4, 110a-2, 110a-3 Liquid level sensor

[0154] 120, 120a ink circulation path

[0155] 130, 130a Pump

[0156] 141, 141a, 142, 142a, 143, 143a, 144, 144a valve

[0157] 150, 150a filter

[0158] 161, 161a, 162, 162a, 163 Pressure sensor

[0159] 170 Control Department

[0160] 180 Pressure Control Department

[0161] 200 Damper

[0162] 210 Main Body

[0163] 211 Storage Space

[0164] 212, 213 Ink flow path

[0165] 220 Sheet

[0166] 300 Degassing tube

[0167] 310 Pressure Reducing Pump

[0168] J connector.

Claims

1. An ink supply system comprising: Tanks, storing ink; an ink supply path for supplying ink from the tank to the inkjet head; an ink return path for returning ink from the inkjet head to the tank; a pump disposed in the ink return path; and a damper disposed in the ink return path between the inkjet head and the pump, The damper comprises: a storage chamber storing the ink; and The telescopic member is in contact with at least the ink stored in the storage chamber.

2. An ink supply system comprising: Tanks, storing ink; an ink circulation path connecting the tank and the inkjet head so as to circulate the ink between the tank and the inkjet head; and A pump is provided in the ink circulation path. At least two or more components provided in the ink circulation path are integrated.

3. An ink supply system comprising: a tank storing ink; and A degassing tube is provided in the tank to degas the gas in the ink. At least a portion of the degassing tube is disposed in the ink, and the degassing tube is depressurized.

4. The ink supply system according to claim 2, wherein: The ink circulation path comprises: an ink supply path connecting the tank and an ink inlet of the inkjet head; and The ink return path connects the ink outlet of the inkjet head and the tank. The ink supply system further comprises: a first pressure sensor disposed in the ink supply path; a second pressure sensor disposed in the ink return path; and The flow rate calculation unit calculates a flow rate of the ink flowing through the ink circulation path based on a differential pressure between detection pressures obtained by the first pressure sensor and the second pressure sensor.

5. The ink supply system according to claim 3, wherein: The ink supply system further includes a pressure control unit that controls the pressure in the tank.

6. The ink supply system according to claim 1, wherein: The lower portion of the tank is connected to one end of the ink supply path, and the upper portion of the tank is connected to one end of the ink return path, A throttle portion is formed at the lower part of the tank, which narrows as it goes downward. One end of the ink supply path is connected to the throttle portion.

7. The ink supply system according to claim 2, wherein: The ink circulation path comprises: an ink supply path connecting the tank and an ink inlet of the inkjet head; and The ink return path connects the ink outlet of the inkjet head and the tank. The lower portion of the tank is connected to one end of the ink supply path, and the upper portion of the tank is connected to one end of the ink return path, A throttle portion is formed at the lower part of the tank, which narrows as it goes downward. One end of the ink supply path is connected to the throttle portion.

8. The ink supply system according to claim 6 or 7, wherein: One end of the ink return path is connected to a position along the wall surface of the tank above the throttle portion.

9. The ink supply system according to claim 8, wherein: A liquid level sensor for detecting a liquid level in the tank is provided on a wall surface of the tank that is opposed to a wall surface of the tank connected to one end of the ink return path.

10. The ink supply system according to claim 1, wherein: The ink supply system further comprises: a pressure sensor provided in the ink supply path or the ink return path; The pressure sensor is connected to an upper pipe portion of the ink supply path or the ink return path.

11. The ink supply system according to claim 2, wherein: The ink supply system further comprises: a pressure sensor disposed in the ink circulation path; The pressure sensor is connected to an upper pipe portion of the ink circulation path.

12. The ink supply system according to claim 2, wherein: The ink supply system further comprises: a damper provided in the ink circulation path between the inkjet head and the pump, absorbing the pulsation of the ink by the expansion and contraction of the expansion and contraction member; The damper is integrated with the pump.

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