Liquid ejection device, liquid ejection method, manufacturing method for article, control program, and recording medium

Abstract

To provide a technique for supplying ink from a main tank to a sub-tank without decreasing production efficiency of printing.SOLUTION: A liquid ejection device includes: a first flow passage which is a first circulation passage to which a main tank is connected; a second flow passage to which a sub-tank and a liquid ejection unit are connected; a third flow passage which connects the first flow passage and the sub-tank and includes flow passage opening / closing means; and a control unit; wherein the control unit opens the flow passage opening / closing means while circulating ink in the first flow passage, replenishing the sub-tank with ink from the main tank via the third flow passage while ejecting the ink from the liquid ejection unit; and closes the flow passage opening / closing means when the replenishment of the sub-tank with the ink from the main tank is completed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a liquid ejection device, a liquid ejection method using the liquid ejection device, and the like.

Background Art

[0002] In the field of liquid ejection devices such as so-called inkjet printers, there is known a device that includes a main tank for storing a liquid and a sub-tank for supplying the liquid to a discharge head, and supplies the liquid from the main tank to the sub-tank as necessary.

[0003] Patent Document 1 discloses a method for improving the controllability of the pressure at the nozzle position by arranging pressure sensors before and after a discharge head in a circulation flow path including the discharge head and a sub-tank and making the flow path resistances between the pressure sensors before and after and the discharge head equal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The device disclosed in Patent Document 1 includes a main tank for supplying ink to a sub-tank. However, when supplying ink, the flow path valve of the circulation flow path is closed, and the ink is supplied from the main tank to the sub-tank with the discharge head stopped. Since the discharge head is stopped while the ink is being supplied from the main tank to the sub-tank, there is a problem that the production efficiency of printing decreases. Therefore, there has been a demand for a technique for supplying ink from a main tank to a sub-tank without reducing the production efficiency of printing.

Means for Solving the Problems

[0006] A first aspect of the present invention is a liquid dispensing device comprising: a first flow path which is a first recirculating flow path to which a main tank is connected; a second flow path to which a sub-tank and a liquid dispensing unit are connected; a third flow path which connects the first flow path and the sub-tank and is equipped with a flow path opening / closing means; and a control unit, wherein the control unit opens the flow path opening / closing means while circulating ink in the first flow path, supplies ink from the main tank to the sub-tank via the third flow path while dispensing ink from the liquid dispensing unit, and closes the flow path opening / closing means when the supply of ink from the main tank to the sub-tank is completed.

[0007] Furthermore, a second aspect of the present invention is a liquid dispensing method using a liquid dispensing device comprising: a first flow path which is a first recirculating flow path to which a main tank is connected; a second flow path to which a sub-tank and a liquid dispensing unit are connected; and a third flow path which connects the first flow path and the sub-tank and is equipped with a flow path opening / closing means, characterized in that the flow path opening / closing means is opened while ink is circulated in the first flow path, ink is supplied from the main tank to the sub-tank via the third flow path while ink is discharged from the liquid dispensing unit, and the flow path opening / closing means is closed when the supply of ink from the main tank to the sub-tank is completed. [Effects of the Invention]

[0008] According to the present invention, it is possible to supply ink from the main tank to the sub-tank without reducing the printing production efficiency. [Brief explanation of the drawing]

[0009] [Figure 1] (a) A schematic top view of the liquid dispensing device 1 according to Embodiment 1. (b) A schematic side view of the liquid dispensing device 1 according to Embodiment 1. [Figure 2] A diagram illustrating the configuration of the ink supply system of the liquid ejection device 1 according to Embodiment 1. [Figure 3] A block diagram illustrating the control system of the liquid dispensing device 1 according to Embodiment 1. [Figure 4] A flowchart illustrating the procedure for ink supply operation according to Embodiment 1. [Figure 5] A diagram illustrating the configuration of the ink supply system of the liquid ejection device 1 according to Embodiment 2. [Figure 6] A diagram illustrating the configuration of the ink supply system of the liquid ejection device 1 according to Embodiment 3. [Modes for carrying out the invention]

[0010] First, an outline of an embodiment of the present invention that can supply liquid from a main tank to a sub-tank without reducing the production efficiency of printing will be described. In this specification, the liquid handled by the liquid dispensing device may be referred to as "ink," but the ink in the embodiment is not limited to liquids for forming characters or images. For example, it may be a liquid containing functional materials for forming functional thin films such as electrodes or optical filters, or functional elements such as organic EL elements. Also, the act of dispensing liquid and applying it to an object may be referred to as "recording," but recording here is not necessarily limited to recording information such as characters or images, but also includes, for example, applying liquid to an object to form a functional thin film or functional element. Furthermore, the object to which the liquid is applied may be referred to as a "recording medium," but the recording medium is not limited to a medium for recording information such as characters or images, but includes components and articles that serve as substrates for forming functional thin films or functional elements.

[0011] The liquid dispensing device of this embodiment includes a first flow path including a main tank and a second flow path connecting the dispensing head and a sub-tank. The first and second flow paths are configured to independently continue to flow the liquid (ink). This is to ensure stable dispensing of not only inks containing soluble recording materials, but also inks containing insoluble particles such as pigment inks, quantum dot inks, silver inks, and white inks. By continuously flowing the ink, it is possible to prevent insoluble components from settling or adhering to the main tank, sub-tank, flow paths, etc., which would result in uneven ink concentration.

[0012] In the liquid ejection device of this embodiment, when the ink level in the sub-tank becomes low, the ink in the second channel is allowed to flow, continuing to eject ink from the ejection unit, while the first channel and the sub-tank are connected via the third channel to replenish ink from the main tank to the sub-tank. When connecting, the liquid pressure in the first channel and the pressure in the sub-tank are measured, and the liquid pressure in the first channel is adjusted based on the measurement results before connection. That is, the pressure difference between the first channel and the sub-tank is controlled to be within a predetermined range before connecting the first channel and the sub-tank. This control maintains a pressure difference that allows ink to be replenished from the main tank to the sub-tank, while preventing large changes in the ink pressure at the ejection unit during replenishment from the main tank to the sub-tank, thus preventing fluctuations in ejection performance. Once the supply of ink from the main tank to the sub-tank is complete, the connection between the first channel and the sub-tank is disconnected. Thereafter, the first channel and the second channel can continue to flow ink independently. According to the liquid ejection device of this embodiment, stable, high-quality printing can be continuously performed without reducing the production efficiency of printing.

[0013] Several embodiments are described below with reference to the drawings. The embodiments shown below are illustrative, and for example, those skilled in the art can modify the detailed configuration as appropriate without departing from the spirit of the present invention. In the drawings referenced below, elements indicated with the same reference numeral have the same function unless otherwise specified. These drawings are schematic representations for the convenience of illustration and explanation, and may not strictly correspond to the actual shape, size, arrangement, etc.

[0014] [Embodiment 1] (Overall structure) First, the overall configuration of the liquid dispensing device according to Embodiment 1 will be described. Figure 1(a) is a schematic top view of the liquid dispensing device 1, and Figure 1(b) is a schematic side view. For the sake of illustration, general components that are not directly related to the problem-solving principle of the present invention have been omitted from the description.

[0015] The liquid dispensing device 1 includes a base 9, on which a stage 10 is provided for setting a recording medium 6 (for example, a substrate for forming an organic EL element). A sub-scanning guide rail 7, extending in the X direction in a plan view, is fixed to the base 9 via a support member 8. A main scanning guide rail 5, acting as a carriage that can move along the X direction on the sub-scanning guide rail 7, is mounted on the sub-scanning guide rail 7, and a main scanner 4, which can move along the Y direction on the main scanning guide rail 5, is mounted on the main scanning guide rail 5. A liquid dispensing unit 2 capable of dispensing liquid toward the recording medium 6 is attached to the main scanner 4. By moving the main scanning guide rail 5 in the X direction and the main scanner 4 in the Y direction, the liquid dispensing unit 2 can be freely scanned in the XY direction on the recording medium 6 set on the stage 10.

[0016] The liquid ejection unit 2 is equipped with a liquid ejection head 3 capable of ejecting a liquid (for example, ink for forming an organic EL element) toward the recording medium 6. The liquid ejection head 3 is equipped with a device that applies pressure to the ink using, for example, the deformation of a piezo element or the film boiling of a heating element to eject the ink from the nozzles. The liquid ejection unit 2 is equipped with a second flow path 16 including a sub-tank for supplying ink to the liquid ejection head 3. The second flow path 16 will be described in detail later with reference to FIG. 2.

[0017] The main tank 11 is installed on the stage 10. Ink is stored in the main tank 11 for replenishment when the ink remaining amount in the sub-tank of the liquid ejection unit 2 decreases. The main tank 11 is connected to a first flow path 15 for circulating the stored ink. The first flow path 15, which is a circulation path, includes a hydraulic pressure gauge 122 and the like. The configuration of the first flow path 15 will be described in detail later with reference to FIG. 2.

[0018] The liquid ejection device 1 includes a third flow path 21 that connects the sub-tank of the liquid ejection unit 2 and the first flow path 15 in an openable and closable manner. Since the sub-tank moves as the liquid ejection unit 2 is XY-scanned, the third flow path 21 is configured to include a flexible pipe portion. An opening and closing valve is installed in the middle of the third flow path 21. The configuration of the third flow path 21 will be described in detail later with reference to FIG. 2.

[0019] (Configuration of Ink Supply System) Referring to FIG. 2, the configuration of the ink supply system of the liquid ejection device 1 according to Embodiment 1 will be described. On the left side of FIG. 2, a first flow path 15 (which may also be referred to as a first circulation path) for circulating the ink stored in the main tank 11 is shown. In the first flow path 15, the main tank 11, the first pump 17, the filter 18, the hydraulic pressure gauge 122, and the branch portion BR to the third flow path 21 are connected in series. A first pressure control unit 12 is connected to the main tank 11, and as will be described later, the control unit can control the drive of the first pressure control unit 12 to control the hydraulic pressure of the first flow path in the vicinity of the branch portion BR. Specifically, the first pressure control unit 12 can be composed of a tube pump, a diaphragm pump, a piston pump, or the like. The first pump 17 is constantly driven except when the liquid ejection device 1 is subjected to main maintenance, and the ink stored in the main tank ired in the main tank 11 constantly circulates along the first flow path 15 in the direction of D1. Incidentally, in order to improve the accuracy of hydraulic pressure control when replenishing ink from the main tank 11 to the sub-tank 13, which will be described later, the hydraulic pressure gauge 122 is preferably disposed in the vicinity of the branch portion BR on the upstream side of the branch portion BR in the direction of D1 in which the circulation occurs.

[0020] The portion surrounded by the dotted line on the right side of FIG. 2 is the portion mounted on the liquid ejection unit 2, and a second flow path 16 for supplying ink to the liquid ejection head 3 (liquid ejection portion) is shown. In the second flow path 16, the sub-tank 13, the second pump 20, and the liquid ejection head 3 are connected in series to form a circulation path (which may also be referred to as a second circulation path). A second pressure control unit 14 is connected to the sub-tank 13, and the control unit can control the drive of the second pressure control unit 14 to control the hydraulic pressure of the ink supplied to the liquid ejection head 3. Specifically, the second pressure control unit 14 can be composed of a tube pump, a diaphragm pump, a piston pump, or the like, but it is particularly preferable to use a piston pump in order to enhance the controllability of the hydraulic pressure at the connection position of the liquid ejection head 3. The second pump 20 is constantly driven except when the liquid ejection unit 2 is subjected to main maintenance, and the ink stored in the sub-tank 13 constantly circulates along the second flow path 16 in the direction of D2.

[0021] The first flow path 15 and the second flow path 16 are connected by a third flow path 21 equipped with an openable and closable valve 19 (flow path opening and closing means). Specifically, the branch BR of the first flow path 15 and the sub-tank 13 are connected by the third flow path 21. The valve 19 located in the middle of the third flow path 21 is opened when replenishing ink from the main tank 11 to the sub-tank 13, as will be described later, but is closed at all other times.

[0022] (Control system) The control system of the liquid dispensing device 1 according to this embodiment will be described with reference to the block diagram in Figure 3. Note that in Figure 3, the functional elements necessary to explain the features of this embodiment are represented as functional blocks, but general functional elements not directly related to the problem-solving principle of the present invention are omitted. Furthermore, each functional element shown in Figure 3 is a functional concept and does not necessarily need to be physically configured as shown. For example, the specific forms of distribution and integration of each functional block are not limited to the illustrated examples, and all or part of them can be functionally or physically distributed and integrated in any unit depending on the usage situation, etc. Each functional block can be configured using hardware or software. That is, some of these functional blocks can be configured, for example, by the CPU reading and executing a control program stored in a memory device or non-temporary recording medium. Alternatively, some or all of the functional blocks may be configured using hardware such as an ASIC.

[0023] The control unit 100 of the liquid dispensing device 1 includes a CPU 101, ROM 102 (Read Only Memory), RAM 103 (Random Access Memory), and an input / output interface 104. The control unit 100 is connected to the host device 110 of the recording system (or goods production system) via interface 111. The host device 110 is composed of a computer equipped with a printer driver and the like, and is responsible for creating printing data and overall management of the recording system. Liquid dispensing patterns, commands, status signals, etc., are transmitted and received between the host device 110 and the control unit 100 of the liquid dispensing device 1 via interface 111.

[0024] The CPU 101 is a computer that controls the operation sequence and execution of various tasks of the liquid dispensing device 1. The CPU 101 can read and execute control programs and control information from the ROM 102 or a computer-readable recording medium (not shown). The computer-readable recording medium can be connected to the CPU 101 via the input / output interface 104, and can be a flexible disk, optical disk, magneto-optical disk, magnetic tape, non-volatile memory such as a USB memory, or an SSD. The RAM 103 is a storage device that temporarily stores the results of the calculation processing of the CPU 101 and various data, and includes an area for deploying the liquid dispensing pattern and a work area for replenishing ink from the main tank 11 to the sub-tank 13.

[0025] The control unit 100 can acquire various measurement data from various sensors 120 provided by the liquid dispensing device 1 via the input / output interface 104. The various sensors 120 may include, but are not limited to, a substrate sensor 121 for detecting the setting of the recording medium 6, a hydraulic pressure gauge 122 provided in the first flow path 15, a pressure sensor 123 provided in the first pressure control unit 12 of the main tank 11, a pressure sensor 124 provided in the second pressure control unit 14 of the sub-tank 13, a liquid level sensor 125 for detecting the remaining ink level in the sub-tank 13, and a temperature sensor 126 for detecting the temperature of the liquid dispensing head 3. The control unit 100 can acquire various measurement data from the various sensors 120 and control the operation of each part of the device based on them.

[0026] The control unit 100 can control various control elements of the liquid ejection device 1 via the input / output interface 104. For example, the control unit 100 can control the ejection of ink from the liquid ejection unit 2 by sending a control signal to the head driver 130. The control unit 100 can also control the X-direction position of the main scanning guide rail 5 and the Y-direction position of the main scanner 4 by sending control signals to the X-position control unit 131X and the Y-position control unit 131Y, thereby scanning the liquid ejection unit 2 to any desired position. Furthermore, the control unit 100 can independently control the first pressure control unit 12 of the main tank 11 and the second pressure control unit 14 of the sub-tank 13 by sending control signals to the drivers 132 and 133. In addition, the control unit 100 can independently control the first pump 17 of the first flow path 15 and the second pump 20 of the second flow path 16 by sending control signals to the pump drivers 134 and 135. Furthermore, the control unit 100 can control the opening and closing of the valve 19 provided in the third flow path 21 by sending a control signal to the driver 136.

[0027] (Operation of the liquid dispensing device) Referring to the flowchart in Figure 4, the procedures for ink ejection and supply operations performed in the liquid ejection device 1 will be explained.

[0028] When the liquid dispensing device 1 is powered on and starts operating, in step S1, the control unit 100 performs a process to put the liquid dispensing device 1 into standby mode. The control unit 100 closes the valve 19 of the third flow path 21, disconnecting the connection between the first flow path 15 and the second flow path 16. The control unit 100 also drives the first pump 17 to control the flow of ink stored in the main tank 11 back into the first flow path 15. Thereafter, the first pump 17 continues to operate unless it receives a stop command from the control unit 100, and the ink stored in the main tank 11 continues to flow back into the first flow path 15. The control unit 100 also drives the second pump 20 to control the flow of ink stored in the sub-tank 13 back into the second flow path 16. Thereafter, the second pump 20 continues to operate unless it receives a stop command from the control unit 100, and the ink stored in the sub-tank 13 continues to be supplied to the liquid dispensing head 3 while flowing back into the second flow path 16.

[0029] When the standby liquid ejection device 1 receives a print command from the host device 110, it starts ejecting ink while scanning the liquid ejection unit 2 on the recording medium 6 in the XY direction. That is, in step S2, the liquid ejection head 3 starts ejecting ink and ejects ink onto the recording medium 6 according to the recording pattern. Thereafter, unless a stop command is received from the control unit 100, such as when replacing the recording medium 6, the liquid ejection head 3 continues its ejection operation and continues to eject ink onto the recording medium 6 according to the recording pattern. Once ejection onto one recording medium 6 is complete, a new recording medium 6 is set on the stage 10, and the liquid ejection head 3 continues to eject ink.

[0030] Next, in step S3, the control unit 100 obtains a measurement result from the liquid level sensor 125 of the sub-tank 13 and measures the remaining amount of ink in the sub-tank 13. In the following step S4, the control unit 100 determines whether the measured amount of ink remaining in the sub-tank 13 is below a predetermined amount. In this embodiment, 20 ml is used as the determination threshold, but the determination threshold can be appropriately set according to the specifications of the device so that the timing of replenishing ink to the sub-tank 13 can be accurately determined. If the measured amount of ink remaining in the sub-tank 13 is greater than the predetermined amount (step S4: NO), there is no need to replenish ink in the sub-tank 13, so the liquid ejection head 3 continues to eject ink according to the recording pattern and the process returns to step S3. Thereafter, steps S3 and S4 are repeated while the liquid ejection head 3 continues to eject ink until the measured amount of ink remaining falls below the predetermined amount.

[0031] If the measured ink level in the sub-tank 13 falls below a predetermined amount (step S4: YES), the control unit 100 executes the processes from step S5 onward to replenish ink from the main tank 11 to the sub-tank 13. Even while the processes from step S5 onward are being executed, the liquid ejection unit 2 continues its ejection operation and can continue to eject ink according to the recording pattern.

[0032] In step S5, the control unit 100 obtains a measured value of the pressure P2 of the sub-tank 13 from the pressure sensor 124 provided by the second pressure control unit 14.

[0033] In step S6, the control unit 100 controls the first pressure control unit 12 of the main tank 11 so that the liquid pressure near the branch BR of the first flow path 15 satisfies the relationship shown in equation (1) below. 100[Pa]+P3≦P1-P2≦300[Pa]+P3...Formula (1)

[0034] However, P1 is the hydraulic pressure in the first flow path near the branching point BR, specifically the measurement value from the hydraulic gauge 122. P2 is the pressure in the sub-tank 13, specifically the measurement value from the pressure sensor 124 of the second pressure control unit 14 acquired in step S5. P3 is the pressure loss value that occurs in the third flow path 21 from the branching point BR to the sub-tank 13. Specifically, P3 is data stored in the memory unit of the control unit 100 after experimentally supplying ink from the main tank 11 to the sub-tank 13 and measuring the pressure loss that occurs in the third flow path 21. If the magnitude of the pressure loss that occurs in the third flow path 21 changes depending on the magnitude of (P1-P2), the pressure loss may be measured while changing (P1-P2), and the relationship between (P1-P2) and P3 may be represented in a table or formula and stored in the memory unit of the control unit 100.

[0035] In step S7, the control unit 100 checks whether the relationship in equation (1) above is satisfied. If it is not yet satisfied (step S7: NO), it repeats steps S5 to S7 until it is satisfied. If the relationship in equation (1) is satisfied (step S7: YES), it proceeds to step S8, where the control unit 100 opens the valve 19 of the third flow path 21 to supply ink from the main tank 11 to the sub-tank 13.

[0036] In this embodiment, when ink is replenished, (P1-P2) is controlled to (100[Pa]+P3) or higher, ensuring a sufficient pressure difference to flow ink from the main tank 11 to the sub-tank 13. Furthermore, since (P1-P2) is controlled to (300[Pa]+P3) or lower, excessive pressure fluctuations in the sub-tank 13 during ink replenishment can be prevented, and pressure fluctuations in the liquid ejection head 3, which communicates with the sub-tank 13, can be suppressed. Therefore, even when ink is replenished to the sub-tank 13 while continuing to eject ink from the liquid ejection head 3, fluctuations in ejection characteristics are suppressed, and the printing quality does not deteriorate. In other words, the liquid ejection device 1 of this embodiment can supply ink from the main tank 11 to the sub-tank 13 while maintaining printing quality without reducing the printing production efficiency. Furthermore, the values ​​of 100 [Pa] and 300 [Pa] included as constants in equation (1) can be appropriately changed depending on the specific configuration of the second flow path, the allowable time for ink replenishment, the background pressure sensitivity of the ejection head's ejection characteristics, the viscosity of the ink, and other factors.

[0037] When the control unit 100 detects that a predetermined amount of ink has been supplied to the sub-tank 13 using the liquid level sensor 125, it proceeds to step S9 and closes the valve 19 of the third flow path 21, thereby disconnecting the connection between the first flow path 15 and the sub-tank 13.

[0038] In the following step S10, it is determined whether to continue ejecting ink. Unless there are circumstances such as receiving a print stop command from the host device 110, the system usually continues ejecting ink (step S10: YES), so it returns to step S3 and continues ejecting ink while monitoring the remaining ink level in the sub-tank 13 again. If, in step S10, a print stop command is received from the host device 110 or for other reasons (step S10: NO), the system proceeds to step S11 and stops ejecting ink.

[0039] As described above, the liquid dispensing device of this embodiment makes it possible to supply liquid from the main tank to the sub-tank without reducing the printing production efficiency.

[0040] [Embodiment 2] The liquid dispensing device according to Embodiment 2 will now be described. The liquid dispensing device of Embodiment 2 differs from the liquid dispensing device of Embodiment 1 in the configuration of the second flow path that supplies ink to the liquid dispensing head. For this embodiment, explanations of matters common to Embodiment 1 will be simplified or omitted.

[0041] (Overall structure) The overall configuration of the liquid dispensing device according to Embodiment 2 is the same as that of Embodiment 1, which was described with reference to Figures 1(a) and 1(b), so its description will be omitted.

[0042] (Ink supply system configuration) Referring to Figure 5, the configuration of the ink supply system of the liquid dispensing device according to Embodiment 2 will be described. On the left side of Figure 5, the first flow path 15 (first recirculation flow path) for circulating the ink stored in the main tank 11 is shown, and its configuration is the same as in Embodiment 1. That is, the main tank 11, the first pump 17, the filter 18, the hydraulic pressure gauge 122, and the branch BR to the third flow path 21 are connected in series to the first flow path 15. The main tank 11 is connected to the first pressure control unit 12, and as will be described later, the control unit can control the drive of the first pressure control unit 12 to control the hydraulic pressure in the first flow path near the branch BR. Specifically, the first pressure control unit 12 can be composed of a tube pump, a diaphragm pump, a piston pump, etc. The first pump 17 is driven at all times except when the liquid dispensing device 1 is being maintained, and the ink stored in the main tank 11 is constantly circulating in the first flow path 15 along the direction of D1. Furthermore, in order to improve the accuracy of hydraulic pressure control when supplying ink from the main tank 11 to the sub-tank 13A, as described later, it is preferable to position the hydraulic pressure gauge 122 upstream of the branching section BR in the direction of the circulating flow D1, and near the branching section BR.

[0043] The area enclosed by the dotted line on the right side of Figure 5 is the part mounted on the liquid ejection unit 2, and shows the second flow path 16 for supplying ink to the liquid ejection head 3. In contrast to the second flow path 16 in Embodiment 1, which was a circular flow path connected to the sub-tank 13, the second flow path 16 in this embodiment is a reciprocating flow path in which the liquid ejection head 3 is positioned between sub-tank 13A (sub-tank A) and sub-tank 13B (sub-tank B).

[0044] A second pressure control unit 14A is connected to sub-tank 13A, and a second pressure control unit 14B is connected to sub-tank 13B. The control units control the driving of the second pressure control units 14A and 14B to generate a pressure difference between sub-tanks 13A and 13B and supply ink to the liquid discharge head 3. If the pressure in sub-tank 13A is made higher than that in sub-tank 13B, the ink can be made to flow in the direction of D3, and conversely, if the pressure in sub-tank 13B is made higher than that in sub-tank 13A, the ink can be made to flow in the direction of D4. In this embodiment, by constantly flowing ink between the two sub-tanks using the second flow path 16, which is a reciprocating flow path, it is possible to prevent insoluble components from settling or adhering and causing the concentration of the ink supplied to the liquid discharge head 3 to become uneven.

[0045] In this embodiment as well, the first flow path 15 and the sub-tank 13A are connected by a third flow path 21 equipped with an openable / closable valve 19. Specifically, the branch BR of the first flow path 15 and the sub-tank 13A are connected by the third flow path 21. The valve 19, located in the middle of the third flow path 21, is opened when replenishing ink from the main tank 11 to the sub-tank 13A, as will be described later, but is closed at other times.

[0046] (Control system) The configuration of the control system is the same as that of Embodiment 1 described with reference to Figure 3, except that there are two second pressure control units and two liquid level sensors because there are two sub-tanks.

[0047] (Operation of the liquid dispensing device) The procedure for the ink supply operation performed in the liquid dispensing device of this embodiment is basically the same as that of Embodiment 1, which was described with reference to the flowchart in Figure 4. However, in this embodiment, the flow of ink in the second flow path, which is started in step S1, is a reciprocating flow rather than a circulating flow.

[0048] Furthermore, in this embodiment, the measurement of the remaining ink level in step S3 is performed by calculating the sum of the remaining amounts in both sub-tanks based on the measurement values ​​from the liquid level sensor of sub-tank 13A and the liquid level sensor of sub-tank 13B.

[0049] Furthermore, in this embodiment, the hydraulic pressure measurement of the second flow path in step S5 is performed by measuring the pressure P2 of the sub-tank 13A with a pressure sensor provided in the second pressure control unit 14A. Then, in step S7, when determining whether the aforementioned equation (1) is true, the measured value of the pressure P2 of the sub-tank 13A is used as P2.

[0050] In this embodiment as well, when ink is replenished, (P1-P2) is controlled to (100[Pa]+P3) or higher, ensuring a sufficient pressure difference to allow ink to flow from the main tank 11 to the sub-tank 13A. Furthermore, since (P1-P2) is controlled to (300[Pa]+P3) or lower, pressure fluctuations in the sub-tank 13A during ink replenishment can be suppressed, preventing excessive pressure fluctuations in the liquid ejection head 3 that communicates with the sub-tank 13A. Therefore, even when ink is replenished to the sub-tank 13A while continuing to eject ink from the liquid ejection head 3, fluctuations in ejection characteristics are suppressed, and the printing quality does not deteriorate. In other words, the liquid ejection device of this embodiment can supply ink from the main tank 11 to the sub-tank 13A while maintaining printing quality without reducing the printing production efficiency.

[0051] [Embodiment 3] A liquid dispensing device according to Embodiment 3 will now be described. The liquid dispensing device 1 according to Embodiment 1 was configured to supply ink from one main tank to one liquid dispensing unit. In contrast, this embodiment is configured to supply ink from one main tank to three liquid dispensing units. Of course, it is also possible to configure it to supply ink from one main tank to two or four or more liquid dispensing units.

[0052] (Ink supply system configuration) Referring to Figure 6, the configuration of the ink supply system of the liquid dispensing device according to Embodiment 3 will be described. On the left side of Figure 6, a first flow path 15 (first recirculation flow path) for circulating the ink stored in the main tank 11 is shown. The first flow path 15 is connected in series to the main tank 11, a first pump 17, a filter 18, a pressure gauge 122A, a branch to the third flow path 21A, a pressure gauge 122B, a branch to the third flow path 21B, a pressure gauge 122C, and a branch to the third flow path 21C. A first pressure control unit 12 is connected to the main tank 11, and the control unit can control the drive of the first pressure control unit 12 to control the liquid pressure in the first flow path near each branch. Specifically, the first pressure control unit 12 can be composed of a tube pump, a diaphragm pump, a piston pump, etc. The first pump 17 is always driven except when the liquid dispensing device is being maintained, and the ink stored in the main tank 11 is constantly circulating along the first flow path 15 in the direction of D1. In order to improve the accuracy of hydraulic pressure control when supplying ink from the main tank 11 to the sub-tanks of each liquid dispensing unit, it is preferable that the hydraulic system at the branching point to each liquid dispensing unit be located upstream of the branching point in the direction of circulation D1, and near the branching point.

[0053] The right side of Figure 6 shows the components mounted on the three liquid ejection units. To distinguish the three liquid ejection units, the reference numerals of each component are appended with either A, B, or C. The ink supply system of each liquid ejection unit is the same as that of the liquid ejection unit according to Embodiment 1, which was described with reference to the right side of Figure 2.

[0054] In this embodiment, each liquid dispensing unit is driven independently, and ink replenishment in the sub-tank when the ink level decreases is performed independently for each liquid dispensing unit.

[0055] For example, consider a liquid discharge unit comprising a sub-tank 13A (which may also be called a second sub-tank), a second pump 20A, a second flow path 16A (which may also be called a fourth flow path), a liquid discharge head 3A (which may also be called a second liquid discharge unit), and a second pressure control unit 14A. In this liquid discharge unit, if the ink level in sub-tank 13A falls below a predetermined amount, ink is supplied from the main tank 11 to sub-tank 13A via the third flow path 21A (which may also be called a fifth flow path). At that time, before opening the valve 19A (which may also be called a second flow path opening / closing means), the first pressure control unit 12 of the main tank 11 is controlled in the same manner as in Embodiment 1, based on the measurement value of the pressure sensor in the second pressure control unit 14A of sub-tank 13A and the measurement value of the hydraulic pressure gauge 122A of the first flow path 15. The same control is performed when supplying ink to liquid discharge units whose reference numerals end in B or C.

[0056] In this embodiment, in a liquid ejection device equipped with multiple liquid ejection units, when ink is replenished to the sub-tank of any liquid ejection unit, (P1-P2) is controlled to (100[Pa]+P3) or higher, so that a sufficient pressure difference is ensured to allow ink to flow from the main tank 11 to the sub-tank. Furthermore, since (P1-P2) is controlled to (300[Pa]+P3) or lower, excessive pressure fluctuations in the sub-tank during ink replenishment can be prevented, and pressure fluctuations in the liquid ejection head communicating with the sub-tank can be suppressed. Therefore, even if ink is replenished to the sub-tank while ink continues to be ejected from the liquid ejection head, fluctuations in ejection characteristics are suppressed, and the printing quality does not deteriorate. In addition, in this embodiment, while ink is being replenished to the sub-tank of any liquid ejection unit, the ink supply system (second flow path) of the other liquid ejection units is disconnected from the first flow path by the valve of the third flow path. Therefore, the other liquid ejection units can continue to eject ink without being affected by the replenishment operation to any liquid ejection unit.

[0057] Thus, in this embodiment of the liquid ejection device, it is possible to supply ink from the main tank 11 to any liquid ejection unit while maintaining print quality without reducing the production efficiency of printing. In other words, since ink can be replenished while ensuring the pressure controllability of the liquid ejection head, productivity improvements can be achieved with a multi-head system.

[0058] [Other embodiments] It should be noted that the present invention is not limited to the embodiments and examples described above, and many modifications are possible within the technical concept of the present invention. For example, the different embodiments and examples described above may be combined and implemented.

[0059] For example, in the embodiment described above, the third channel 21 is configured to connect the first channel 15 and the sub-tank 13, but it may also be configured to connect the first channel 15 and the second channel 16 near the sub-tank 13. The point is that any configuration that allows ink to be supplied from the main tank to the sub-tank is acceptable.

[0060] Furthermore, in Embodiment 3, multiple liquid discharge units with the same configuration as in Embodiment 1 are provided for one main tank, but multiple liquid discharge units with the same configuration as in Embodiment 2 may also be provided. Alternatively, both liquid discharge units with the same configuration as in Embodiment 1 and liquid discharge units with the same configuration as in Embodiment 2 may be provided for one main tank.

[0061] The embodiments of the present invention also include a "method for manufacturing an article" in which an article is manufactured by dispensing, for example, an ink containing raw materials for a functional thin film or a functional element, using a liquid dispensing apparatus or liquid dispensing method of the embodiment.

[0062] The present invention can also be realized by supplying a program that implements one or more of the functions of the embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions. [Explanation of Symbols]

[0063] 1···Liquid discharge device / 2···Liquid discharge unit / 3, 3A, 3B, 3C··Liquid discharge head / 4···Main scanner / 5···Main scan guide rail / 6···Recording medium / 7···Sub-scan guide rail / 8···Support member / 9···Base / 10···Stage / 11···Main tank / 12···First pressure control unit / 13, 13A, 13B, 13C··Sub-tank / 14, 14A, 14B···Second pressure control unit / 15···First flow path / 16, 16A, 16B, 16C...Second channel / 17...First pump / 18...Filter / 19, 19A, 19B, 19C...Valve / 20, 20A, 20B, 20C...Second pump / 21, 21A, 21B, 21C...Third channel / 100...Control unit / 101...CPU / 102...ROM / 103...RAM / 104...Input / Output interface / 110...Host device / 122, 122A, 122B, 122C...Hydraulic gauge

Claims

1. a first flow path serving as a first circulation flow path to which a main tank is connected; a second flow path connected to the sub-tank and the liquid ejection unit; a third flow path that connects the first flow path and the sub-tank and is provided with a flow path opening and closing means; A control unit, The control unit is while circulating ink in the first flow path, when a difference between a liquid pressure in the first flow path and a pressure in the sub-tank is within a predetermined range, the flow path opening and closing means is opened, and ink is replenished from the main tank to the sub-tank via the third flow path; when the supply of ink from the main tank to the sub-tank is completed, the flow passage opening and closing means is closed. A liquid ejection device comprising:

2. A first flow path which is a first circulation flow path to which a main tank is connected; a second flow path connected to the sub-tank and the liquid ejection unit; a third flow path that connects the first flow path and the sub-tank and is provided with a flow path opening and closing means; A control unit, The control unit is opening the flow passage opening and closing means while circulating ink in the first flow passage, and replenishing ink from the main tank to the sub tank via the third flow passage while discharging ink from the liquid discharge portion; when the supply of ink from the main tank to the sub-tank is completed, the flow passage opening and closing means is closed. A liquid ejection device comprising:

3. the control unit opens the flow passage opening / closing means when a difference between the hydraulic pressure in the first flow passage and the pressure in the sub-tank is within a predetermined range. The liquid ejection device according to claim 2 .

4. The control unit opens the flow path gating means when the following formula (1) is satisfied:

4. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device. 100[Pa]+P3≦P1-P2≦300[Pa]+P3...Formula (1) P1 is the hydraulic pressure in the first flow path. P2 is the pressure in the subtank. P3 is the pressure loss occurring in the third flow path.

5. the control unit controls the pressure of the main tank so that a difference between the hydraulic pressure of the first flow path and the pressure of the sub tank falls within a predetermined range before opening the flow path opening / closing means.

5. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

6. The control unit controls the pressure of the main tank so that the following formula (2) is satisfied before opening the flow path opening and closing means.

6. The liquid ejection device according to claim 1, 100[Pa]+P3≦P1-P2≦300[Pa]+P3...Formula (2) P1 is the hydraulic pressure in the first flow path. P2 is the pressure in the subtank. P3 is the pressure loss occurring in the third flow path.

7. the second flow path is a second circulation flow path to which the sub-tank and the liquid ejection unit are connected; 7. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

8. The sub-tank is configured to include a sub-tank A and a sub-tank B, the second flow path is a reciprocating flow path capable of reciprocating ink between the sub-tank A and the sub-tank B, The third flow path connects the first flow path and the sub-tank A.

7. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

9. a fourth flow path to which the second sub-tank and the second liquid ejection unit are connected; a fifth flow path including a second flow path opening / closing means and connecting the first flow path and the second sub-tank; 9. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

10. The ink contains a functional material for forming a functional thin film or a functional element.

10. The liquid ejection device according to claim 1,

11. a first flow path serving as a first circulation flow path to which a main tank is connected; a second flow path connected to the sub-tank and the liquid ejection unit; a third flow path that connects the first flow path and the sub-tank and is provided with a flow path opening and closing means; A liquid ejection method using a liquid ejection device comprising: while circulating ink in the first flow path, when a difference between a liquid pressure in the first flow path and a pressure in the sub-tank is within a predetermined range, the flow path opening and closing means is opened, and ink is replenished from the main tank to the sub-tank via the third flow path; when the supply of ink from the main tank to the sub-tank is completed, the flow passage opening and closing means is closed. A liquid ejection method comprising:

12. A first flow path which is a first circulation flow path to which a main tank is connected; a second flow path connected to the sub-tank and the liquid ejection unit; a third flow path that connects the first flow path and the sub-tank and is provided with a flow path opening and closing means; A liquid ejection method using a liquid ejection device comprising: opening the flow passage opening and closing means while circulating ink in the first flow passage, and replenishing ink from the main tank to the sub tank via the third flow passage while discharging ink from the liquid discharge portion; when the supply of ink from the main tank to the sub-tank is completed, the flow passage opening and closing means is closed. A liquid ejection method comprising:

13. when a difference between the hydraulic pressure in the first flow path and the pressure in the sub-tank is within a predetermined range, the flow path opening and closing means is opened. The liquid ejection method according to claim 12 .

14. The flow path gating means is opened when the following formula (1) is satisfied:

14. The liquid ejection method according to claim 11, 100[Pa]+P3≦P1-P2≦300[Pa]+P3...Formula (1) P1 is the hydraulic pressure in the first flow path. P2 is the pressure in the subtank. P3 is the pressure loss occurring in the third flow path.

15. before opening the flow passage opening / closing means, the pressure of the main tank is controlled so that the difference between the hydraulic pressure of the first flow passage and the pressure of the sub-tank is within a predetermined range.

15. The liquid ejection method according to claim 11,

16. before opening the flow path opening and closing means, the pressure of the main tank is controlled so that the following formula (2) is satisfied:

16. The liquid ejection method according to claim 11, 100[Pa]+P3≦P1-P2≦300[Pa]+P3...Formula (2) P1 is the hydraulic pressure in the first flow path. P2 is the pressure in the subtank. P3 is the pressure loss occurring in the third flow path.

17. the second flow path is a second circulation flow path to which the sub-tank and the liquid ejection unit are connected; 17. The liquid ejection method according to claim 11,

18. The sub-tank is configured to include a sub-tank A and a sub-tank B, the second flow path is a reciprocating flow path capable of reciprocating ink between the sub-tank A and the sub-tank B, The third flow path connects the first flow path and the sub-tank A.

17. The liquid ejection method according to claim 11,

19. a fourth flow path to which the second sub-tank and the second liquid ejection unit are connected; a fifth flow path including a second flow path opening / closing means and connecting the first flow path and the second sub-tank; 18. The liquid ejection method according to claim 11,

20. The ink contains a functional material for forming a functional thin film or a functional element.

20. The liquid ejection method according to claim 11,

21. A method for manufacturing an article, comprising discharging ink containing a raw material for a functional thin film or a functional element onto a substrate by the liquid discharge method according to claim 20.

22. A control program for causing a computer that controls the liquid ejection apparatus to execute the liquid ejection method according to any one of claims 11 to 20.

23. A computer-readable recording medium having the control program according to claim 22 recorded thereon.

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