Liquid ejection device, liquid ejection method, article manufacturing method and recording medium

Abstract

This invention provides a liquid ejection device, a liquid ejection method, an article manufacturing method, and a recording medium capable of suppressing the sedimentation of high-density solid components in a flow path and suppressing fluctuations in the concentration of solid components in ink. The liquid ejection device comprises: a cartridge for storing liquid; an ejector head for ejecting the liquid; a circulation path for the liquid to return from the cartridge via the ejector head to the cartridge; and a control unit, wherein the circulation path comprises: a filter flow path through a filter; and a filter bypass flow path arranged parallel to the filter flow path, and the control unit controls the ratio of the flow rate of the liquid flowing in the filter flow path to the flow rate of the liquid flowing in the filter bypass flow path.

Description

Technical Field

[0001] This invention relates to a liquid ejection device and a liquid ejection method using the liquid ejection device. Background Technology

[0002] In the field of liquid ejection devices such as inkjet printers, liquid supply systems are known that include a cartridge for storing ink, a filter disposed between the cartridge and the print head, and a liquid delivery component that supplies ink from the cartridge to the print head.

[0003] When using ink containing insoluble solid components with a specific gravity greater than that of the solvent, the ink is circulated between the cartridge and the print head to suppress the sedimentation of the solid components.

[0004] Patent document 1 discloses a printing apparatus in which a carriage filter and a circulation filter are arranged in the flow path for circulating white ink containing white pigment components.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-147270 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In the printing apparatus disclosed in Patent Document 1, in order to suppress the clogging of the carriage filter which is time-consuming to replace, a circulation filter with a finer mesh than the carriage filter is used to capture more of the condensed ink.

[0010] In this device, by continuously circulating the ink, the sedimentation of solid components in the pipes of the supply system can be suppressed. Furthermore, it is expected that premature clogging of the carriage filter due to condensed ink can be prevented, which is a time-consuming process for replacement.

[0011] However, while this device can remove impurities or clumps through filters, during prolonged ink circulation, solid components that should be present in the ink can be captured by the carriage filter and circulation filter. If the concentration of solid components in the ink is lower than its intended value, even if a specified amount of ink is ejected from the printhead, the ink delivered to the recording medium may not perform as intended.

[0012] Therefore, there is a need for a liquid ejection device that can suppress the sedimentation of high-density solid components in the flow path and suppress the variation in the concentration of solid components in the ink.

[0013] Solution for solving the problem

[0014] A first aspect of the present invention is a liquid ejection device comprising: a container for storing liquid; a nozzle for ejecting the liquid; a circulation path for the liquid to flow from the container through the nozzle back to the container; and a control unit, characterized in that the circulation path comprises: a filter flow path via a filter; and a filter bypass flow path arranged parallel to the filter flow path, wherein the control unit controls the ratio of the flow rate of the liquid flowing in the filter flow path to the flow rate of the liquid flowing in the filter bypass flow path.

[0015] Furthermore, a second aspect of the present invention is a liquid ejection method using a liquid ejection device comprising: a container capable of storing liquid; a nozzle capable of ejecting the liquid; a circulation path serving as a flow path for the liquid, returning from the container to the container via the nozzle; and a control unit, characterized in that the circulation path comprises: a filter flow path via a filter; and a filter bypass flow path arranged parallel to the filter flow path, wherein the control unit controls the ratio of the flow rate of the liquid flowing in the filter flow path to the flow rate of the liquid flowing in the filter bypass flow path according to an operating mode. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the overall structure of the liquid ejection device 100 according to Embodiment 1.

[0017] Figure 2 This is a schematic block diagram used to illustrate the control unit 20.

[0018] Figure 3 This is a flowchart illustrating the change in the operating mode of the liquid ejection method in embodiments 1 to 4.

[0019] Figure 4 This is a flowchart illustrating the control method for the liquid flow path in Embodiment 1.

[0020] Figure 5 This is a schematic diagram showing the overall structure of the liquid ejection device 500 in Embodiment 2.

[0021] Figure 6 This is a flowchart illustrating the control method for the liquid flow path in Embodiment 2.

[0022] Figure 7 This is a schematic diagram showing the overall structure of the liquid ejection device 700 in Embodiment 3.

[0023] Figure 8 This is a flowchart illustrating the control method for the liquid flow path in Embodiment 3.

[0024] Figure 9This is a schematic diagram showing the overall structure of the liquid ejection device 900 in Embodiment 4.

[0025] Figure 10 This is a flowchart illustrating the control method for the liquid flow path in Embodiment 4.

[0026] Figure 11 This is a flowchart used to illustrate the sequence of actions in step S100.

[0027] Figure 12 This is a valve control table used to explain the control state of the valve in embodiment 4.

[0028] Figure 13 This is a schematic diagram illustrating the sequence of introducing gas into the flow path to recover the ink from filter 3 into ink cartridge 2.

[0029] Figure 14 This is a schematic diagram illustrating the sequence in which the introduced gas is discharged from the flow path. Detailed Implementation

[0030] Referring to the accompanying drawings, liquid ejection devices and liquid ejection methods, which are embodiments of the present invention, will be described. The embodiments shown below are examples; for example, for small structures, those skilled in the art can make appropriate modifications and implement them without departing from the spirit of the present invention.

[0031] In the accompanying drawings referred to in the following description of the embodiments, unless otherwise specified, elements indicated by the same reference numerals have the same function.

[0032] In addition, for the purpose of illustration and explanation, sometimes the accompanying drawings are used to represent the objects schematically. Therefore, the shape, size, and arrangement of the elements shown in the accompanying drawings are sometimes not strictly consistent with the actual objects.

[0033] The liquid ejection device described in the following embodiments can also be a device for ejecting liquid (ink) for recording text and images, but is not limited thereto. For example, it can also be a device for coating liquid (ink) containing functional materials to form functional films or functional elements such as electrodes, anti-conduction films, filters, resist patterns for forming electronic circuits, films for three-dimensional modeling, and organic EL elements. In the following description, the operation of the liquid ejection device ejecting liquid (ink) to apply liquid (ink) to an object is sometimes referred to as "recording," but recording here is not limited to recording information such as text and images. For example, it also includes cases where liquid containing functional materials is ejected and applied to an object (the substrate of the article) in order to manufacture articles such as functional films or functional elements.

[0034] The liquid ejection device of the embodiment illustrated below has a circulation path (liquid flow path) for ejecting liquid from and returning it to the box. The circulation path includes a filter flow path through a filter and a filter bypass flow path arranged in parallel with the filter flow path.

[0035] The liquid ejection device of this embodiment can perform a cleaning mode that removes impurities from the ink using a filter. In cleaning mode, the liquid flow path can be controlled such that all or more of the circulating ink passes through the filter flow path, and zero or less than 30% passes through the filter bypass flow path. By continuously circulating the ink without stopping along the circulation path, impurities in the ink can be removed using the filter, while suppressing the sedimentation of solid components in the liquid flow path.

[0036] The liquid ejection device is capable of executing an ejection mode that ejects ink from the printhead. In ejection mode, the fluid flow path is controlled such that ink is supplied from the cartridge to the printhead via a filter bypass path, and ink not consumed by the printhead circulates back to the cartridge. In ejection mode, by continuously circulating the ink along the circulation path, not only is ink supplied to the printhead, but the sedimentation of solid components in the liquid flow path is also suppressed. Furthermore, in ejection mode, the liquid flow path can be controlled such that all or more of the ink supplied to the printhead passes through the filter bypass path, while zero or less than 30% passes through the filter path. This prevents or suppresses the capture of solid components that should be present in the ink by the filter, and suppresses the reduction of the concentration of solid components in the ink.

[0037] Furthermore, even in modes other than those described above (e.g., a standby mode where neither cleaning nor dispensing is performed), the liquid dispensing device of this embodiment can continuously circulate the ink in the liquid flow path to suppress the settling of solid components. In this case, the liquid flow path can be controlled such that all or more of the circulating ink passes through the filter bypass path, and zero or less than 30% passes through the filter path. This prevents or reduces the capture of solid components that should be present in the ink by the filter, and suppresses the reduction of the concentration of solid components in the ink.

[0038] In the liquid dispensing device of this embodiment, a cleaning mode is implemented to remove impurities from the ink when ink is replenished to the cartridge or when a replacement cartridge filled with ink is installed. After the cleaning mode ends, the system switches to other operating modes, but the ink continues to circulate to suppress the settling of solid components. In other operating modes, flow path control is performed to prevent or reduce the capture of solid components that should be present in the ink by the filter. That is, the liquid flow path is controlled such that all or more of the circulating ink flows through the filter bypass path, and zero or less than 30% flows through the filter path. As a result, fluctuations in the concentration of solid components in the ink after impurities have been removed can be suppressed, and the settling of solid components in the liquid flow path can be suppressed.

[0039] Therefore, according to the liquid ejection apparatus and liquid ejection method of the embodiments, since ink containing a specified concentration of solid components can be stably applied to an object, the applied ink can perform its original performance. For example, when recording text or images, text or images can be recorded with desired color or density; when using liquid containing functional materials to form functional films or functional elements, functional films or functional elements with desired performance can be manufactured.

[0040] [Implementation Method 1]

[0041] (Structure of the liquid ejection device)

[0042] First, the overall structure of the liquid ejection device 100 of Embodiment 1 will be described. Figure 1 This is a schematic diagram showing the structure of the liquid ejection device 100. Furthermore, for ease of explanation, general components (such as the frame, power supply, etc.) that are not directly related to the principle of solving the problem of this invention are omitted from the diagram.

[0043] The liquid ejection device 100 includes an ejector head 1 capable of ejecting ink, an ink cartridge 2 capable of storing ink, a filter 3, a pump 4, a flow path control valve 6, and a flow path control valve 9, which are connected via a liquid flow path. That is, the ink cartridge 2 is connected to the pump 4 via a flow path 11, and the pump 4 is connected to the flow path control valve 6 via a flow path 5. As the pump 4, a diaphragm pump, tubular pump, or piston pump, which are known as liquid pumps, can be used. Preferably, the pump 4 operates continuously to circulate ink, except when performing maintenance on the liquid ejection device 100, to prevent the sedimentation of solid components.

[0044] Between flow path control valve 6 and flow path control valve 9, a filter flow path 7 passing through filter 3 and a filter bypass flow path 8 bypassing filter 3 are arranged in parallel. Flow path control valve 6 and flow path control valve 9 are three-way valves capable of switching the flow path connection. Flow path control valve 9 is connected to printhead 1 via flow path 10, and printhead 1 is connected to ink cartridge 2 via flow path 12.

[0045] Furthermore, the ink cartridge 2 can be either a fixed type or a replaceable type. Ink can be replenished by injecting ink into a fixed cartridge or by installing a replaceable cartridge already filled with ink. Additionally, a pressure control mechanism (not shown) can be provided in the ink cartridge 2. This pressure control mechanism can control the air pressure inside the cartridge to an appropriate pressure (e.g., negative pressure), thereby supplying ink from the ink cartridge 2 to the print head 1 under conditions suitable for ink ejection.

[0046] The liquid ejection device 100 includes a control unit 20 for controlling the operation of each part. Figure 2This is a schematic block diagram illustrating the control unit 20. The control unit 20 is a computer used to control the operation of the liquid dispensing device 100, and internally includes a CPU, ROM, RAM, I / O ports, etc. The ROM stores the operating program of the liquid dispensing device 100.

[0047] The actions involved in the liquid ejection method of this embodiment are executed under the management of the control unit 20. The control unit 20 stores control programs for the actions of various components such as the pump 4, flow path control valve 6, flow path control valve 9, and ejection head 1. The control program for the liquid ejection method can be stored in ROM like other action programs, but it can also be loaded into RAM from an external source via a network. Alternatively, the control program can be loaded into RAM via a computer-readable recording medium such as a floppy disk, optical disk, optical disc, magnetic tape, USB memory, or SSD.

[0048] The I / O ports can connect to external devices or networks, enabling input and output of data required for ink ejection control between the device and an external computer 21. Furthermore, the I / O ports can connect to a display or input device (not shown) to display operational status information of the liquid ejection device 100 to the operator or to receive commands from the operator.

[0049] The control unit 20 is connected to controlled elements such as the pump 4, flow path control valve 6, flow path control valve 9, and nozzle 1, enabling signal transmission and control over them. Furthermore, the control unit 20 is connected to various sensors installed in the ink cartridge 2, such as the liquid level sensor 22, pressure sensor 23, and temperature sensor 24, enabling signal transmission and acquisition of the measurement information required for control. Figure 2 The control elements of the present invention are shown, but other control elements of the liquid ejection device, such as control elements related to the position control of the ejection head, sensors, etc., are omitted from the illustration.

[0050] (Ink and filter)

[0051] The ink ejected by the liquid ejection device 100 of this embodiment may contain insoluble solid components. For example, in this embodiment, it is preferable to use ink containing acrylic monomer as the main component and TiO2 particles as the insoluble solid component. The TiO2 particles have a central particle size of 200 nm and a particle size distribution of 100 to 700 nm. The concentration of the insoluble solid component in the ink is 7 wt%. However, the ink used in the liquid ejection device of the present invention is not limited to this example, and the type, particle size, concentration, and main component of the insoluble solid component are not limited to this example. The particle size of the insoluble solid component is preferably 50 nm or more and 2 μm or less. The viscosity of the ink used in this embodiment is 10 mPa·s at room temperature (e.g., 23°C ± 2°C), but it is not limited to this example. As long as it is in the range of 1.0 mPa·s or more and 40 mPa·s or less at room temperature, it can be used without problems.

[0052] By strictly managing the manufacturing process of ink, the impurities contained in the freshly manufactured ink can be kept below a specified level. However, when the ink is filled into containers, transported to containers, or replenished to liquid dispensing devices after manufacturing, relatively large impurities may be introduced into the ink.

[0053] Therefore, the liquid ejection device 100 of this embodiment includes a filter 3 for removing solid impurities from the replenished ink. As the filter 3, a so-called capsule filter is preferably used. A capsule filter is a filter in which a filter medium (filter material) is housed in a capsule-shaped shell; it has relatively low pressure loss and can stably filter ink. However, the capsule filter is just one example, and the liquid ejection device of the present invention can also include other types of filters.

[0054] As the filter medium (filter material) built into the housing, for example, membrane sheets, fibers, or particulate matter can be used as porous membranes. An appropriate filter medium (filter material) can be selected by considering factors such as impurities that may be mixed into the ink and the particle size of the solid components originally contained in the ink. In the description of this embodiment, the term "filtration size" is sometimes used as an indicator of the filter's filtration capacity. Filtration size refers to the smallest particle size that the filter can remove substantially all (e.g., 99.9% or more) of when a liquid containing particles passes through the filter once.

[0055] If the filter size is too small, not only impurities but also insoluble solids that should be contained in the ink may be captured by the filter. Therefore, it is necessary to set the filter size appropriately. In this embodiment, the filter size of the filter 3 is preferably 5 to 100 times the central particle size of the insoluble solids that should be contained in the ink, and preferably smaller than the nozzle diameter of the inkjet head. Here, the central particle size refers to the diameter of the most abundant particles, that is, the particle size corresponding to the center of the particle size distribution. In this embodiment, since the central particle size of the TiO2 particles contained in the ink is 200 nm, a filter material with a filter size of 5 μm (or 10 μm) is selected. Filter materials with a filter size in the range of 1 μm to 20 μm are preferred, but the filter size can be appropriately set according to the particle size of the insoluble solids in the ink and the particle size of the impurities that should be removed from the ink.

[0056] In filters with large filter media surface areas, such as capsule filters, even if the filter size is set as described above, insoluble solids smaller than the filter size may adhere to the surface of the filter media and be captured by it. That is, if ink continues to pass through the filter for an extended period after impurities are removed, there is a possibility that the insoluble solids that should be present in the ink will be captured and reduced. Therefore, in this embodiment, a filter bypass flow path 8 that bypasses the filter 3 is provided parallel to the filter flow path 7 that passes through the filter 3, allowing for appropriate control of the flow path during ink circulation.

[0057] (Liquid ejection method)

[0058] Figure 3 This is a flowchart illustrating the sequence of liquid ejection methods using the liquid ejection device 100.

[0059] When the liquid dispensing device 100 begins operation, the control unit 20 executes a cleaning mode in step S1 to remove impurities from the ink stored in the ink cartridge 2. Specifically, the control unit 20 drives the pump 4 and controls the flow path control valves 6 and 9, connects the flow path 5 and flow path 10 through the filter flow path 7, and closes the filter bypass flow path 8. As a result, the ink continuously circulates (circulates) along the C1~C3~C4~C5 indicated by arrows in the diagram, removing impurities using the filter 3. During the execution of the cleaning mode, the continuous circulation of ink suppresses the settling of solid components in the liquid flow path. In the example ink cartridge 2, which contains 500 ml of ink, the pump 4 is driven at a flow rate of 50 ml / min; however, this is just an example, and other conditions are possible.

[0060] In step S2, the control unit 20 determines whether the ink cleaning has been sufficiently performed. If it determines that the cleaning has not been sufficiently performed (step S2: No), it returns to step S1 and continues to execute the cleaning mode. To determine whether the ink cleaning has been sufficiently performed, judgment conditions can be preset based on factors such as the particle size of impurities that may be contained in the ink, the filter size of the filter 3, the amount of ink stored in the ink cartridge 2, and the delivery capacity of the pump 4. For example, the cleaning mode can be implemented in advance through experiments, and the concentration of impurities remaining in the ink can be measured over time to determine the time required until the cleaning is sufficiently performed, and this time can be stored in the control unit 20. In this way, the control unit 20 can determine whether the cleaning has been sufficiently performed by measuring the execution time of the cleaning mode using a timer program or the like.

[0061] If the cleaning mode is run for an extended period, there is a possibility that insoluble solids that should be present in the ink may adhere to the filter. Therefore, the concentration of insoluble solids in the ink can be measured over time to determine the optimal running time. For example, in this embodiment, although the cleaning mode operating time is set to 1 hour, it has been confirmed that most impurities are removed without a change in the concentration of insoluble solids within the measurement accuracy of the TGA (thermogravimetric analyzer). The cleaning mode operating time can be set such that when the concentration of insoluble solids in the ink stored in cartridge 2 is measured by the TGA, the reduction is contained to be 0.2 wt% or less, preferably 0.1 wt% or less. Of course, the cleaning mode operating time is not limited to this example, and appropriate judgment conditions can be set according to the particle size of the impurities, the filter size of the filter 3, the amount of ink stored in cartridge 2, the delivery capacity of the pump 4, etc.

[0062] If it is determined that ink cleaning has been sufficiently performed (step S2: Yes), the control unit 20 ends the cleaning mode in step S3 and then proceeds to step S4 to determine whether the liquid ejection operation should be started immediately. Specifically, it determines whether a liquid ejection command has been received.

[0063] If no liquid ejection command is received (step S4: No), proceed to step S9, and control unit 20 executes standby mode. Specifically, control unit 20 continues to drive pump 4 and controls flow path control valves 6 and 9 to connect flow path 5 and flow path 10 via filter bypass flow path 8, while closing filter flow path 7. Thus, ink continuously circulates (circulates) along the paths C1~C2~C4~C5 as indicated by the arrows in the diagram.

[0064] During standby mode, the ink continues to circulate, thus suppressing the sedimentation of solid components in the ink within the liquid flow path. Furthermore, since filter flow path 7 is closed, solid components that should be present in the ink are not captured by filter 3, suppressing changes in solid component concentration. Then, the processing cycle (step S4: No) to (step S9) is repeated to continue standby mode until a liquid ejection command is received, suppressing fluctuations in the concentration of solid components in the ink and preventing solid component sedimentation.

[0065] Upon receiving a liquid ejection command (step S4: Yes), the process proceeds to step S5, where the control unit 20 executes the liquid ejection mode. Specifically, the control unit 20 continues to drive the pump 4 and controls the flow path control valves 6 and 9, connecting flow path 5 and flow path 10 via the filter bypass flow path 8, while closing the filter flow path 7. As a result, ink is supplied to the print head 1 via arrows C1 to C2 to C4 in the diagram and ejected from the print head. Additionally, any remaining ink not ejected from the print head circulates along arrow C5 via flow path 12 back to the ink cartridge 2.

[0066] Because the ink circulates continuously during liquid ejection mode, the settling of solid components in the ink within the liquid flow path is suppressed. Furthermore, since filter flow path 7 is closed, solid components that should be present in the ink are not captured by filter 3, thus suppressing fluctuations in solid component concentration.

[0067] Next, in step S6, the control unit 20 determines whether the liquid ejection mode should be terminated (whether the required ejection action has been completed). If the liquid ejection mode is terminated (step S6: Yes), the process proceeds to step S9, and the standby mode is executed. Then, the processing loop of steps S4 to S9 is repeated to continue the standby mode until a liquid ejection command is received. However, as described above, during the execution of the standby mode, changes in the concentration of solid components in the ink are suppressed.

[0068] If the liquid ejection mode has not ended (step S6: No), the liquid ejection mode continues, but the process proceeds to step S7, where the control unit 20 determines whether the elapsed time since the end of the cleaning mode in step S3 has exceeded a predetermined time. In this embodiment, after the cleaning mode ends, a standby mode or a liquid ejection mode is executed to continuously circulate the ink, thus suppressing the sedimentation of solid components in the ink in the liquid flow path. However, if a long time has passed since cleaning, new impurities may be introduced into the ink from the outside, or solids in the ink may agglomerate to form large-diameter lumps unsuitable for ejection from the ejector head 1. Therefore, in this embodiment, in step S7, it is determined whether the elapsed time since the end of the cleaning mode has exceeded a predetermined time. If the predetermined time has exceeded (step S7: Yes), the process returns to step S1 to execute the cleaning mode again. The predetermined time can be appropriately set in advance through experiments and stored in the control unit 20 as a judgment criterion.

[0069] In this embodiment, the criterion is whether the elapsed time since the end of the cleaning mode exceeds 12 hours. However, the determination condition in step S7 is not limited to this, and other conditions can also be set. For example, during the execution of the ejection mode, the velocity of the ejected droplets, the landing position and shape of the droplets landing on the recording medium can be measured to determine whether the prescribed ejection performance has been maintained. If not, the process returns to step S1 and the cleaning mode is executed again. At this time, in step S7, the control unit 20 can also use the ejector head 1 to record a test pattern, measure the position and shape of the landing ink droplets, and perform the above-mentioned determination.

[0070] If the elapsed time since the end of the cleaning mode has not exceeded the predetermined time (step S7: No), the liquid dispensing mode continues to be executed, but the control unit 20 uses the liquid level sensor 22 to check the remaining ink level of the ink cartridge 2 in step S8. If the remaining ink level is less than the predetermined amount, it is determined that ink needs to be replenished (step S8: Yes), and ink is replenished to the ink cartridge 2 in step S10. In this embodiment, the predetermined amount (determination threshold) is set to 50 ml, but it is not limited to this example, and an appropriate determination threshold can be set. When the ink replenishment is completed, the process moves to step S1, and the control unit 20 executes the cleaning mode that has already been explained. If it is determined that ink replenishment is not needed (step S8: No), the process returns to step S5, and the control unit 20 continues to execute the liquid dispensing mode.

[0071] Above, refer to Figure 3 The sequence of operations of the liquid ejection device 100 has been explained. Next, refer to... Figure 4 This will be explained from the perspective of liquid flow path control methods.

[0072] When the liquid dispensing device 100 starts operating, in step S21, ink cartridge 2 is replenished with, for example, 500 ml of ink. Then, in step S22, the process is completed along... Figure 1 The loop path (circulation path) is shown by the middle arrow, C1~C3~C4~C5. Step S22 is equivalent to... Figure 3 The cleaning mode described in step S1 constitutes a circulation path (loop path) using filter flow path 7. At this time, pump 4 is driven at a flow rate of, for example, 50 ml / min.

[0073] The circulation path (circulation path) of filter flow path 7 is continuously constructed, and the ink continues to circulate until a flow path change is determined in step S23. Furthermore, step S23 and... Figure 3 This corresponds to step S2 in the text.

[0074] When it is determined in step S23 that it is a flow path change moment (step S23: Yes), in step S24, a portion of the path is formed that is a different loop flow path from the previous one. That is, in step S24, a loop flow path is formed along... Figure 1 The loop path (circulation path) is shown by the middle arrow, C1~C2~C4~C5. Step S24 is equivalent to... Figure 3 The liquid ejection mode described in step S5 or the standby mode described in step S9 constitutes a circulation path (circulation path) using the filter bypass flow path 8.

[0075] Next, in step S25, it is determined whether the ink circulation performed using the circulation path (circulation path) of the filter bypass flow path 8 has exceeded a predetermined time. Additionally, in Figure 3 The document states that step S7 is performed during execution in liquid ejection mode, but the same determination can also be performed during execution in standby mode. That is, Figure 4 Step S25 can be performed in any operating mode other than the cleaning mode. The specified time, which serves as the criterion for judging step S25, can be appropriately set by investigating the relationship between the duration of ink circulation and the amount of newly mixed impurities through experiments in advance.

[0076] If it is determined in step S25 that the specified time has been exceeded (step S25: Yes), return to step S22 and re-form the loop path (circulation path) using filter flow path 7.

[0077] If it is determined that the specified time has not been exceeded (step S25: No), proceed to step 26 to determine whether ink needs to be added to ink cartridge 2. Additionally, step S26 and... Figure 3 Step S8 corresponds to this.

[0078] If it is determined that ink needs to be replenished (step S26: Yes), return to step S21 and replenish ink to ink cartridge 2.

[0079] If it is determined that no ink replenishment is needed (step S26: No), return to step S24 and continue to construct the loop path (circulation path) using the filter bypass flow path 8.

[0080] As explained above, when ink is replenished to the cartridge, the liquid ejection device of this embodiment implements a cleaning mode in order to remove impurities from the ink by circulating the ink through the filter flow path. In this embodiment, 100% of the ink circulating in the cleaning mode passes through the filter flow path. If the removal of impurities is completed, in order to prevent solid components that should be present in the ink from being captured by the filter, the system is controlled to switch from the filter flow path to the filter bypass flow path and circulate the ink so that the ink does not flow through the filter. In this embodiment, 100% of the ink circulating in the liquid ejection mode or standby mode passes through the filter bypass flow path. As a result, fluctuations in the concentration of solid components in the ink after impurity removal can be suppressed, and the sedimentation of solid components in the liquid flow path can be suppressed. Therefore, according to the liquid ejection device and liquid ejection method of this embodiment, ink containing a predetermined concentration of solid components can be stably applied to the recording medium, thereby allowing the applied ink to perform its intended function. For example, when recording text or images, it is possible to record with the desired color or intensity; when imparting functional materials to liquids, it is possible to manufacture functional films or functional elements with the desired properties.

[0081] [Implementation Method 2]

[0082] Reference Figure 5 The overall structure of the liquid ejection device 500 in Embodiment 2 will be described. Figure 5 This is a schematic diagram showing the structure of the liquid ejection device 500. Furthermore, for ease of explanation, general components (e.g., the frame, power supply, etc.) that are not directly related to the principle of solving the problem of this invention are omitted from the drawings. Elements identical to those in Embodiment 1 are labeled with the same reference numerals, and descriptions are simplified or omitted.

[0083] The liquid ejection device 500 is the same as that in Embodiment 1 in that it includes an ejector head 1, an ink cartridge 2, a filter 3, a pump 4, and a control unit 20. The liquid ejection device 100 of Embodiment 1 includes a flow path control valve 6 and a flow path control valve 9 that can switch the flow path, and is configured to selectively select either the filter flow path 7 or the filter bypass flow path 8. Furthermore, the control unit 20 controls the switching of the flow path, ensuring that ink flows only through the filter flow path 7 in cleaning mode, and only through the filter bypass flow path 8 in liquid ejection mode and standby mode.

[0084] In contrast, the liquid ejection device 500 of Embodiment 2 does not have flow control valves at the branch point P1 and the confluence point P2, but instead has a flow control valve 51 in the filter bypass flow path 8 and a flow control valve 52 in the filter flow path 7. The flow control valves 51 and 52 are valves capable of controlling the flow rate of the flowing liquid, and their operation is controlled by the control unit 20. The control unit 20 can independently control the flow rate of C2 flowing in the filter bypass flow path 8 and the flow rate of C3 flowing in the filter flow path 7.

[0085] Similar to Embodiment 1, the liquid ejection device 500 in this embodiment also follows... Figure 3 The flowchart shown executes various modes including cleaning mode, liquid ejection mode, and standby mode. However, in this embodiment, the flow path control method in each mode differs from that in Embodiment 1.

[0086] Reference Figure 6 This will be explained from the perspective of liquid flow path control methods. Figure 6 In the process, steps S21, S23, S25, and S26 are referenced. Figure 4 The implementation method described is the same as Implementation 1, so the description is omitted.

[0087] In this embodiment, when the ink is circulated in step S61, the control unit 20 controls the flow control valves 51 and 52 to circulate the ink such that the flow rate of the filter flow path 7 is greater than the flow rate of the filter bypass flow path 8 (C3 > C2). In cleaning mode, while removing impurities by allowing more than half of the circulated ink to pass through the filter flow path 7, the ink is also allowed to flow in the filter bypass flow path 8 to suppress the settling of solid components in the filter bypass flow path. The ratio of the flow rates of the filter bypass flow path 8 to the filter flow path 7 in step S61 is set according to the impurity removal capacity of the filter 3 and the ease with which the solid components of the ink settle.

[0088] Generally speaking, in cleaning mode, when the total flow rate of the filter bypass flow path 8 and the filter flow path 7 is 100%, it is preferable to set the flow rate of the filter flow path 7 to 70% or more, and more preferably to 90% or more.

[0089] In this embodiment, when the ink is circulated in step S62, the control unit 20 controls the flow control valves 51 and 52 to circulate the ink such that the flow rate of the filter bypass path 8 is greater than the flow rate of the filter path 7 (C2 > C3). In liquid ejection mode and standby mode, more than half of the circulated ink is passed through the filter bypass path 8 to suppress the sedimentation of solid components in the circulation path. At this time, although the ink is also flowing in the filter path 7 to suppress the sedimentation of solid components in the filter path 7, by reducing the flow rate in the filter path 7, the solid components that should be contained in the ink are not excessively replenished by the filter 3. The ratio of the flow rates of the filter bypass path 8 to the filter path 7 in step S62 can be set according to the ease of sedimentation of solid components in the ink and the ratio of solid components that should be contained in the ink replenished by the filter 3.

[0090] Generally speaking, in liquid ejection mode and standby mode, when the total flow rate of filter bypass flow path 8 and filter flow path 7 is 100%, the flow rate of filter bypass flow path 8 is preferably 70% or more, and more preferably 90% or more.

[0091] In this embodiment, flow control valves 51 and 52 are provided to precisely control the flow ratio between the filter bypass flow path 8 and the filter flow path 7. However, as long as the specified flow ratio can be achieved, the flow control valve can also be provided only in one of the flow paths.

[0092] In this embodiment, the liquid ejection device, when replenishing ink to the cartridge, implements a cleaning mode in order to remove impurities from the ink by circulating the ink primarily through the filter flow path. At this time, a small amount of ink also flows through the filter bypass flow path, thereby suppressing the settling of solid components in the filter bypass flow path. Once impurity removal is complete, control is maintained such that the ink mainly circulates through the filter bypass flow path, thereby suppressing the flow of ink to the filter and reducing the capture of solid components that should be present in the ink by the filter. This suppresses fluctuations in the concentration of solid components in the ink after impurity removal and also suppresses the settling of solid components in the liquid flow path and filter housing. Therefore, according to the liquid ejection device and liquid ejection method of this embodiment, ink containing a predetermined concentration of solid components can be stably applied to the recording medium, thus allowing the applied ink to perform its intended function. For example, when recording text or images, desired colors or shades can be recorded; when applying liquids containing functional materials, functional films or functional elements with desired properties can be manufactured.

[0093] [Implementation Method 3]

[0094] Reference Figure 7The overall structure of the liquid ejection device 700 in Embodiment 3 will be described. Figure 7 This is a schematic diagram showing the structure of the liquid ejection device 700. Furthermore, for ease of explanation, general components (e.g., the frame, power supply, etc.) that are not directly related to the principle of solving the problem of this invention are omitted from the drawings. Elements identical to those in Embodiment 1 are labeled with the same reference numerals, and descriptions are simplified or omitted.

[0095] The liquid ejection device 700 is the same as that in Embodiment 1 in that it includes an ejector head 1, an ink cartridge 2, a filter 3, a pump 4, a flow path control valve 6, a flow path control valve 9, and a control unit 20. In the liquid ejection device 100 of Embodiment 1, ink is circulated in the flow path through the ejector head 1 in any of the cleaning mode, liquid ejection mode, and standby mode.

[0096] In contrast, the liquid ejection device 700 of Embodiment 3 includes an ejection head flow path 71 via the ejection head 1 and an ejection head bypass flow path 72 bypassing the ejection head 1. The ejection head flow path 71 and the ejection head bypass flow path 72 are used separately according to the mode, which is different. That is, in the cleaning mode, the ink circulates via the ejection head bypass flow path 72, while in the liquid ejection mode and the standby mode, the ink circulates via the ejection head flow path 71.

[0097] To achieve this structure, in the liquid ejection device 700, a flow path control valve 61 is provided upstream of the ejection head 1, and a flow path control valve 62 is provided downstream of the ejection head 1. The flow path control valves 61 and 62 are three-way valves that can switch the flow path connection by control of the control unit 20. An ejection head flow path 71 and an ejection head bypass flow path 72 are arranged side by side between the two valves.

[0098] Similar to Embodiment 1, the liquid ejection device 700 in this embodiment also follows... Figure 3 The flowchart shown executes various modes including cleaning mode, ejection mode, and standby mode. However, in this embodiment, the control method of the flow path in each mode differs from that in embodiment 1.

[0099] Reference Figure 8 This will be explained from the perspective of liquid flow path control methods. Figure 8 In the process, steps S21, S23, S25, and S26 are referenced. Figure 4 The implementation method described is the same as Implementation 1, so the description is omitted.

[0100] In this embodiment, when the ink is circulated in step S81, the control unit 20 controls the flow path control valves 6 and 9, connecting flow path 5 and flow path 10 via the filter flow path 7. Simultaneously, the control unit 20 controls the flow path control valves 61 and 62, connecting flow path 10 and flow path 12 via the nozzle bypass flow path 72. According to this embodiment, in the cleaning mode, the ink continuously circulates (circulates) along the arrows C1~C3~C4~C7~C5 in the figure, removing impurities through the filter 3. During the execution of the cleaning mode, since the ink continuously circulates, the sedimentation of solid components in the liquid flow path is suppressed. At this time, since the ink is circulated using the nozzle bypass flow path 72 without passing through the nozzle 1, ink from the cleaning process where impurities are not completely removed will not come into contact with the nozzle 1. Therefore, for example, it is possible to prevent impurities that are not completely removed from adhering to the nozzle 1 during the cleaning process.

[0101] In this embodiment, when the ink is circulated in step S82, the control unit 20 controls the flow path control valves 6 and 9, connecting flow path 5 and flow path 10 via the filter bypass flow path 8. Simultaneously, the control unit 20 controls the flow path control valves 61 and 62, connecting flow path 10 and flow path 12 via the nozzle flow path 71. Therefore, in step S82, when executing the liquid ejection mode or standby mode, the ink continuously circulates (circulates) along the paths C1~C2~C4~C6~C5 as indicated by the arrows in the figure. During the execution of the liquid ejection mode and standby mode, the continuous circulation of ink suppresses the sedimentation of solid components in the liquid flow path. Furthermore, since the filter flow path 7 is closed, solid components that should be present in the ink are not captured by the filter 3, suppressing changes in the concentration of the solid components that should be present.

[0102] As explained above, when ink is replenished to the cartridge, the liquid dispensing device of this embodiment implements a cleaning mode in order to remove impurities from the ink by circulating the ink through the filter flow path. At this time, by circulating the ink through the nozzle bypass flow path 72 instead of through the nozzle 1, it is possible to prevent ink that has not been completely removed during the cleaning process from coming into contact with the nozzle 1.

[0103] Once impurity removal is complete, to prevent solid components that should be present in the ink from being captured by the filter, the ink is circulated by switching from the filter flow path to the filter bypass flow path, thus preventing the ink from flowing within the filter. This suppresses fluctuations in the concentration of solid components in the ink after impurity removal and inhibits the sedimentation of solid components in the liquid flow path. Therefore, the liquid ejection apparatus and method according to this embodiment can stably apply ink containing a predetermined concentration of solid components to the recording medium, allowing the applied ink to perform its intended function. For example, when recording text or images, desired colors or shades can be recorded; when applying liquids containing functional materials, functional films or functional elements with desired properties can be manufactured.

[0104] [Implementation Method 4]

[0105] Reference Figure 9 The overall structure of the liquid ejection device 900 in Embodiment 4 will be described. Figure 9 This is a schematic diagram showing the structure of the liquid ejection device 900. Furthermore, for ease of explanation, general components (e.g., the frame, power supply, etc.) that are not directly related to the principle of solving the problem of this invention are omitted from the drawings. Elements identical to those in Embodiment 3 are labeled with the same reference numerals, and descriptions are simplified or omitted.

[0106] The liquid ejection device 900 is the same as that in embodiment 3 in that it includes an ejector head 1, an ink cartridge 2, a filter 3, a pump 4, a flow path control valve 6, a flow path control valve 9, a flow path control valve 61, a flow path control valve 62, an ejector head flow path 71, an ejector head bypass flow path 72, and a control unit 20.

[0107] In the liquid dispensing device 700 of Embodiment 3, after the cleaning mode is executed, and ink remains in the filter 3, the flow path is switched from the filter flow path 7 to the filter bypass flow path 8 to execute the liquid dispensing mode or the standby mode.

[0108] In contrast, the liquid ejection device 900 of Embodiment 4 removes ink residue from the filter 3 and filter flow path 7 after performing the cleaning mode. This prevents solid components contained in the ink from settling in the housing of the filter 3 containing the filter media (filter material) and the filter flow path 7, and prevents the settling solid components from causing adverse effects when the cleaning mode is performed again.

[0109] Furthermore, the liquid ejection device 900 according to this embodiment is configured to recover ink removed from the filter 3 and the filter flow path 7 back to the ink cartridge 2 and use it for ejection. This allows for the efficient use of ink without waste, which is beneficial in terms of cost and environmental protection.

[0110] Furthermore, according to the liquid ejection device 900 of this embodiment, ink removal from the filter 3 and filter flow path 7 and ink recovery to the ink cartridge 2 are performed by injecting gas into the liquid flow path, followed by venting (degassing) the liquid flow path into which gas was injected. This prevents the gas remaining in the flow path from dissolving into the ink and altering its properties when ink is re-injected into the portion into which gas was injected for ink removal.

[0111] To achieve this purpose, the liquid dispensing device 900 includes: a gas inlet section for introducing gas into the filter flow path and removing ink from the filter flow path; and an exhaust section for exhausting the gas introduced into the filter flow path. Specifically, the liquid dispensing device 900 also includes a flow path opening and closing valve 89, a flow path control valve 90, a flow path 91, a pipeline 92, a pipeline control valve 93, a gas inlet path 94, an exhaust path 95, a gas outlet path 96, an exhaust pump 97, an exhaust path 98, and a degassing assembly 99.

[0112] The flow path on / off valve 89 is disposed on the flow path 12 connecting the flow path control valve 62 and the ink cartridge 2, and is a valve that opens and closes the flow path 12 under the control of the control unit 20. The flow path control valve 90 is a three-way valve that can be switched by the control unit 20 to connect either the flow path 5 and the flow path 91 or the pipeline 92 and the flow path 91. The flow path 91 connects the flow path control valve 90 and the flow path control valve 6, forming part of the circulation flow path for ink circulation.

[0113] Pipeline 92 is a gas flow path that supplies gas to flow path 91 or discharges gas from filter 3, etc., via flow path 91. Pipeline control valve 93 is a three-way valve that can be switched by control unit 20 to connect pipeline 92 to gas inlet path 94 or pipeline 92 to exhaust path 95.

[0114] Gas inlet 94 is a conduit for introducing gas used to remove ink from filter 3 from the outside. The gas used here is preferably one that reacts or dissolves minimally upon contact with the ink, causing minimal changes to the ink's properties. Depending on the type of ink, dry air or dry nitrogen may be used. The gas is supplied from gas inlet 94 at a pressure of, for example, 0.2 atmospheres.

[0115] Exhaust path 95 is a conduit that serves as a flow path for gas when it is discharged from filter 3, etc., and is connected to exhaust pump 97. Exhaust pump 97 can use various vacuum pumps to draw in gas and discharge it to gas discharge path 96. Exhaust pump 97 is also connected to degassing assembly 99 via exhaust path 98. Degassing assembly 99 is, for example, a device that has a tube with a hollow fiber membrane, through which ink is passed to remove air bubbles or dissolved gases in the ink.

[0116] Similar to Embodiment 1 or Embodiment 3, the liquid ejection device 900 in this embodiment also follows... Figure 3 The flowchart shown illustrates the execution of cleaning mode, ejection mode, and standby mode. However, in this embodiment, when the cleaning mode ends, the ink remaining in the filter 3 and filter flow path 7 is removed and recycled back to the ink cartridge 2, and the filter 3 and filter flow path 7 are degassed.

[0117] Reference Figure 10 This will be explained from the perspective of liquid flow path control methods. Figure 10 In addition to step S100, the other steps are the same as those in the reference. Figure 8 The description is the same as that of Implementation 3, so the description is omitted. In this implementation, if the cleaning mode is completed, that is, if step S23 (S2) is "yes", then the process moves to step S100. After the processing in step S100 is completed, the process moves to step S82.

[0118] Reference Figure 11 The flowchart shown illustrates the sequence of processes performed in step S100. When step S100 begins, in step S101, the control unit 20 stops the pump 4, temporarily halting ink circulation.

[0119] Next, in step S102, the control unit 20 uses gas to discharge ink from the filter 3 and recovers the discharged ink into the ink cartridge 2. Figure 12 The upper section of the valve control table shown represents the control commands given by the control unit 20 when controlling each valve in step S102. Additionally, in Figure 13 In the diagram, the flow of gas in step S102 is schematically shown using thick arrows.

[0120] like Figure 13 As shown, the gas introduced from the gas inlet 94 passes through the pipeline control valve 93, pipeline 92, and flow path control valve 90, and is then introduced into the flow path 91. The gas introduced into the flow path 91 pushes the residual ink along the direction of the arrow while traveling within the circulation path. In other words, including the ink remaining in the filter 3, the ink remaining downstream of the flow path control valve 90 is pushed by the introduced gas and flows as shown by the arrow, and is recovered into the ink cartridge 2 through the open flow path on / off valve 89.

[0121] When the remaining ink is recycled back into ink cartridge 2, Figure 11In step S103 of the flowchart shown, the control unit 20 activates the exhaust pump 97, proceeding to step S104. Furthermore, the exhaust pump 97 needs to start operating before step S104, but it does not necessarily have to start operating after step S102. For example, the exhaust pump 97 can be activated in the cleaning mode before starting step S100 and continue operating as before; in this case, step S103 is omitted, and the process proceeds to step S104. If the exhaust pump 97 is activated while the ink is circulating in the cleaning mode, causing the degassing assembly 99 to operate, dissolved gases in the circulating ink can be removed. By maintaining the dissolved oxygen content in the ink at, for example, below 3 ppm, the ejection from the printhead 1 can be stabilized.

[0122] In step S104, the control unit 20 discharges the gas introduced during ink recovery to the ink cartridge 2 in step S103 from the flow path. Figure 12 The middle section of the valve control table shown represents the control commands given by the control unit 20 when controlling each valve in step S104. Additionally, in Figure 14 In the diagram, the flow of the gas discharged in step S104 is schematically shown with thick arrows.

[0123] The circulation path downstream of the flow path control valve 90 is connected to the exhaust pump 97 via the pipeline 92, the pipeline control valve 93, and the exhaust path 95. However, since the flow path opening and closing valve 89 is closed, the gas filled in the flow path is discharged and discharged from the gas exhaust path 96.

[0124] When the gas filling the flow path is discharged, the process proceeds to step S105, where the control unit 20 controls each valve to form the liquid flow path used in step S82, causing the pump 4 to operate. Figure 12 The lower section of the valve control table shown represents the control commands given by the control unit 20 when controlling each valve in step S105. When step S105 is completed, Figure 10 Step S100 is completed, proceed to step S82. Subsequent actions are the same as in embodiment 3.

[0125] As explained above, when the liquid ejection device of this embodiment replenishes ink to the cartridge, it implements a cleaning mode in order to remove impurities from the ink by circulating the ink through the filter flow path. At this time, the ink is circulated using the ejection head bypass flow path 72 instead of through the ejection head 1, thereby preventing ink in the cleaning process from contacting the ejection head 1 if impurities are not completely removed.

[0126] Furthermore, in this embodiment, after the cleaning mode is executed, the ink remaining in the filter 3 and the filter flow path 7 is removed. This prevents solid components contained in the ink from precipitating in the housing of the filter 3 containing the filter media (filter material) and in the filter flow path 7, ensuring that the precipitated solid components do not cause adverse effects when the cleaning mode is executed again.

[0127] Furthermore, in this embodiment, the ink removed from the filter 3 and the filter flow path 7 can be recovered into the ink cartridge 2 for use in inkjet printing. This allows for the efficient use of ink without waste, which is beneficial in terms of cost and environmental protection.

[0128] Furthermore, in this embodiment, ink removal from the filter 3 and filter flow path 7 and ink recovery to the ink cartridge 2 are achieved by injecting gas into the liquid flow path, followed by venting (degassing) the injected liquid flow path. This prevents the gas from dissolving into the ink and altering its properties when ink is re-injected into the portion where gas was injected for ink removal.

[0129] Once these processes are complete, to prevent solid components that should be present in the ink from being captured by the filter, the ink is circulated by switching from the filter flow path to the filter bypass flow path instead of flowing through the filter. This suppresses fluctuations in the concentration of solid components in the ink after impurity removal and prevents solid components from settling in the liquid flow path. Therefore, according to the liquid ejection apparatus and method of this embodiment, since ink containing a predetermined concentration of solid components can be stably applied to the recording medium, the applied ink can perform its intended function. For example, when recording text or images, it is possible to record with the desired color or density; when imparting a liquid containing functional materials, it is possible to manufacture functional films or functional elements with desired properties.

[0130] [Comparison with reference method]

[0131] As explained above, in each embodiment, a filter bypass flow path is provided parallel to the filter flow path. Furthermore, in modes other than the cleaning mode, by allowing at least half (preferably more than 70%) of the circulating ink to pass through the filter bypass flow path, it is possible to prevent the replenishment of solid components that the ink should contain by the filter.

[0132] Here, as a reference, a liquid ejection device is described that has the same ejector head 1, ink cartridge 2, filter 3, and pump 4 as the liquid ejection device 100 of Embodiment 1, but does not have the flow path control valve 6, filter bypass flow path 8, and flow path control valve 9. The reference device is the same as the embodiments in that it circulates ink in any of the cleaning mode, liquid ejection mode, and standby mode, but differs from the embodiments in that it passes all circulated ink through the filter in any mode.

[0133] For the liquid ejection device of the reference method, after replenishing ink cartridge 2, according to... Figure 3The management process shown was implemented continuously for 7 days, and the concentration of insoluble solids in the residual ink in cartridge 2 was investigated to see if it changed. The concentration of insoluble solids in the ink was measured using a TGA (Thermogravimetric Analysis) device, and the results confirmed a decrease of 1.0 wt% compared to the time of ink replenishment. As a result of replenishing the filter, the concentration of insoluble solids in the ink decreased, and after the 7th day, the ink was in a state where it could not perform its original function. Therefore, when recording text or images, the quality of color or density decreased, and when applying liquids containing functional materials, there was a tendency for the performance of functional films or functional elements to deteriorate. Furthermore, the filter became nearly clogged, and there was a tendency for the flow rate of the circulating liquid to decrease.

[0134] In contrast, regarding the liquid dispensing device in each embodiment, after replenishing ink to the ink cartridge 2, it follows... Figure 3 The management process shown was continuously implemented for 10 days to investigate whether the concentration of insoluble solids in the residual ink in cartridge 2 changed. The concentration of insoluble solids in the ink was measured using a TGA (thermogravimetric analyzer), and the results confirmed that there was no change within the measurement accuracy range relative to the time when ink was replenished. According to each embodiment, since ink containing a specified concentration of solids can be stably applied to the recording medium, the applied ink can perform its original performance. Furthermore, it does not cause filter clogging, and compared to the reference method, it can operate continuously for a longer period.

[0135] [Other implementation methods]

[0136] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the technical concept of the present invention. Different embodiments described above can also be combined.

[0137] For example, in Embodiments 3 and 4, similar to Embodiment 1, the flow path control valve 6 and the flow path control valve 9 are configured to switch the filter flow path 7 and the filter bypass flow path 8, but they can also be configured as in Embodiment 2 to change the flow rate of each flow path.

[0138] Furthermore, in embodiments 3 and 4, flow control valves 61 and 62 can be used to switch between the nozzle flow path 71 and the nozzle bypass flow path 72, but other structures can also be used to change the flow ratio for these flow paths. For example, flow control valves can be installed in the nozzle flow path 71 and the nozzle bypass flow path 72 respectively, so that in cleaning mode, more than 70% of the flow rate flows through the nozzle bypass flow path 72, and in liquid spraying mode and standby mode, more than 70% of the flow rate flows through the nozzle flow path 71.

[0139] Alternatively, in addition to the circulation path described in each embodiment, a device structure may be provided on the printhead 1 with a sub-cartridge or sub-circulation path, and the printhead 1 may also have a sub-circulation path for ink circulation.

[0140] In addition, it can also be a liquid spraying device or liquid spraying method that can perform other action modes besides cleaning mode, liquid spraying mode, and standby mode.

[0141] The present invention can also be implemented by supplying a program for implementing the inkjet printing method of the embodiment to a system or device via a network or storage medium, and having the processor in the computer of the system or device read and execute the program. A control program for a control method that causes the control unit to execute the above-described inkjet printing method, and a computer-readable recording medium storing the control program are also included in embodiments of the present invention.

[0142] According to the present invention, a liquid ejection device is provided that can suppress the sedimentation of high-density solid components in the flow path and suppress the variation in the concentration of solid components in the ink.

[0143] [Explanation of reference numerals in the attached figures]

[0144] 1. Printhead; 2. Ink cartridge; 3. Filter; 4. Pump; 5. Flow path; 6. Flow path control valve; 7. Filter flow path; 8. Filter bypass flow path; 9. Flow path control valve; 10, 11, 12. Flow paths; 20. Control unit; 21. External computer; 22. Flow sensor; 23. Pressure sensor; 24. Temperature sensor; 51, 52. Flow control valves; 61, 62. Flow path control valves; 71. Printhead flow path; 72. Printhead bypass flow path; 89. On / off valve; 90. Flow path control valve; 91. Flow path; 92. Piping; 93. Piping control valve; 94. Gas inlet path; 95. Exhaust path; 96. Gas outlet path; 97. Exhaust pump; 98. Exhaust path; 99. Degassing assembly; 100, 500, 700, 900. Liquid ejection device.

Claims

1. A liquid ejection device, The liquid ejection device includes: A box that can store liquids; The nozzle is capable of spraying the liquid. A circulation path, serving as the flow path for the liquid, returns from the container to the container via the nozzle; and Control Department Its features are, The circulation path includes: a filter flow path, passing through a filter; And a filter bypass flow path, arranged in parallel with the filter flow path. The control unit controls the ratio of the flow rate of the liquid flowing in the filter flow path to the flow rate of the liquid flowing in the filter bypass flow path. The control unit is capable of executing a cleaning mode in which more than 70% of the liquid circulating in the circulation path passes through the filter flow path, and a spraying mode in which more than 70% of the liquid circulating in the circulation path is sprayed out of the nozzle while passing through the filter bypass flow path.

2. The liquid ejection device according to claim 1, characterized in that, The circulation path includes a flow control valve, which can switch the flow of the liquid to either the filter flow path or the filter bypass flow path. The control unit controls the flow path control valve to change the ratio of the flow rate of the liquid flowing in the filter flow path and the filter bypass flow path.

3. The liquid ejection device according to claim 1, characterized in that, The circulating flow path includes a flow control valve capable of controlling the flow rate of the liquid flowing in the filter flow path and / or a flow control valve capable of controlling the flow rate of the liquid flowing in the filter bypass flow path. The control unit controls the flow control valve to change the ratio of the flow rate of the liquid flowing in the filter flow path and the filter bypass flow path.

4. The liquid ejection device according to any one of claims 1 to 3, characterized in that, The circulation path also includes a nozzle bypass path arranged parallel to the nozzle. The control unit controls the ratio of the flow rate of the liquid supplied to the nozzle to the flow rate of the liquid flowing in the bypass path of the nozzle.

5. The liquid ejection device according to claim 4, characterized in that, The circulation path includes a flow control valve, which can switch the flow of the liquid to either the nozzle or the nozzle bypass flow path. The control unit controls the flow path control valve to change the ratio of the flow rate of the liquid flowing in the nozzle and the nozzle bypass flow path.

6. The liquid ejection device according to any one of claims 1 to 3, characterized in that, The liquid ejection device includes a gas inlet section for introducing gas into the filter flow path and removing liquid from the filter flow path.

7. The liquid ejection device according to claim 6, characterized in that, The liquid removed from the filter path is recovered into the cartridge.

8. The liquid ejection device according to claim 6, characterized in that, The liquid ejection device includes an exhaust section for discharging the gas that is introduced into the filter flow path.

9. The liquid ejection device according to claim 1, characterized in that, The cleaning mode is performed such that the concentration of insoluble solids in the liquid is reduced to less than 0.2 wt%.

10. The liquid ejection device according to claim 1, characterized in that, The control unit is also capable of executing a standby mode, which is a mode in which more than 70% of the liquid circulating in the circulation path is not ejected from the nozzle while passing through the filter bypass path.

11. The liquid ejection device according to claim 1, characterized in that, If, after executing the cleaning mode, the control unit causes more than 70% of the liquid to circulate in the loop via the filter bypass for a specified time, the cleaning mode is executed again.

12. A liquid ejection method using a liquid ejection device, the liquid ejection device comprising: A box that can store liquids; The nozzle is capable of spraying the liquid. A circulation path, serving as the flow path for the liquid, returns from the container to the container via the nozzle; and Control Department Its features are, The circulation path includes: a filter flow path via the filter; and a filter bypass flow path arranged parallel to the filter flow path. The control unit controls the ratio of the flow rate of the liquid flowing in the filter flow path to the flow rate of the liquid flowing in the filter bypass flow path according to the operating mode. The control unit is capable of executing a cleaning mode in which more than 70% of the liquid circulating in the circulation path passes through the filter flow path, and a spraying mode in which more than 70% of the liquid circulating in the circulation path is sprayed out of the nozzle while passing through the filter bypass flow path.

13. A method for manufacturing an article, characterized in that, Using the liquid ejection method of claim 12, the liquid is ejected from the ejector head and applied to the substrate.

14. A computer-readable recording medium, characterized in that, The computer-readable recording medium is a recording medium that contains a program for executing the liquid ejection method of claim 12 by the control unit and is readable by a computer.

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