Liquid ejecting apparatus, liquid ejecting method, and method for manufacturing article

Abstract

The invention provides a liquid ejecting apparatus, a liquid ejecting method, and a method of manufacturing an article. The present invention reduces the occurrence of uneven concentrations of liquid components inside a liquid cartridge. The liquid ejecting apparatus includes: a liquid cartridge; a discharge head that discharges a liquid; and a liquid circulation device that circulates a liquid. The liquid circulation device includes: a first circulation flow path that returns from the liquid cartridge to the liquid cartridge via the ejection head; and a second circulation flow path that returns from the liquid cartridge to the liquid cartridge without passing through the ejection head. The second circulation flow path includes a first port serving as an outlet for the liquid from the liquid cartridge and a second port serving as a return port for returning the liquid to the liquid cartridge. The second port is provided on the upper side of the first port.

Description

Technical Field

[0001] The present invention relates to a liquid ejection device, a liquid ejection method and a method for manufacturing an article. Background Art

[0002] As an example of a liquid ejection device, there is known an inkjet printer that ejects ink onto a medium such as paper to print an image on the medium. In recent years, inkjet printers have been used in the commercial field to print images onto a medium other than paper such as paper whose base is not white, or a film.

[0003] In addition, in the field of industry, liquid ejection devices are used to eject ink onto a variety of media such as glass substrates, semiconductor substrates, and building materials. Ink also uses solvent-based inks with a relatively high drying speed, and inks with additives that impart properties to the coating film. In recent years, fine particles with a relatively large specific gravity such as titanium oxide have been added as additives to inks that are particularly in high demand. Such insoluble solid components such as fine particles tend to settle inside the liquid box and inside the piping.

[0004] In such a liquid ejection device, a liquid such as ink is circulated between a liquid box and an ejection head. However, it is difficult to reduce the sedimentation of components contained in the liquid, such as insoluble solid components, inside the liquid box and inside the piping only by the circulation flow path of the liquid between the liquid box and the ejection head. If the insoluble solid components settle inside the liquid box, the concentration of the components contained in the liquid will be uneven inside the liquid box. Patent document 1 discloses that a separate circulation flow path is provided that does not pass through the ejection head relative to the circulation flow path that circulates the ink between the ejection head and the ink box.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-98737 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, even if another circulation flow path is connected to the liquid cartridge, there is a possibility that the concentration of the components contained in the liquid may become uneven inside the liquid cartridge, and further improvement is desired.

[0010] Solutions for solving problems

[0011] A technical solution disclosed herein is a liquid ejecting device, characterized in that the liquid ejecting device includes: a liquid box; a ejection head that ejects liquid; and a liquid circulation device that circulates the liquid, the liquid circulation device having: a first circulation flow path that returns from the liquid box via the ejection head to the liquid box; and a second circulation flow path that returns from the liquid box to the liquid box without passing through the ejection head, the second circulation flow path including a first port that serves as an outlet for the liquid from the liquid box and a second port that serves as a return port for the liquid to return to the liquid box, the second port being arranged at an upper side than the first port. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the liquid ejection device according to the first embodiment.

[0013] Figure 2 (a) is a schematic diagram of the ink cartridge according to the first embodiment. Figure 2 (b) is a schematic diagram of the ink cartridge according to the first embodiment. Figure 2 (c) is a schematic diagram of the ink cartridge according to the first embodiment.

[0014] Figure 3 This is a flowchart of the operation of the liquid ejecting device according to the first embodiment.

[0015] Figure 4 It is an explanatory diagram of the operation of the liquid ejecting device according to the first embodiment.

[0016] Figure 5 It is an explanatory diagram of the operation of the liquid ejecting device according to the first embodiment.

[0017] Figure 6 It is an explanatory diagram of the operation of the liquid ejecting device according to the first embodiment.

[0018] Figure 7 (a) is a schematic diagram of a part of the liquid ejection device according to the second embodiment. Figure 7 (b) is a schematic diagram of a part of the liquid ejection device according to the third embodiment. Figure 7 (c) is a schematic diagram of a part of the liquid ejection device according to the fourth embodiment.

[0019] Figure 8 (a) is a schematic diagram of a liquid ejection device according to a fifth embodiment. Figure 8 (b) is a schematic diagram of the ink cartridge according to the fifth embodiment.

[0020] Fig. 9 (a) is a schematic diagram of a part of the liquid ejection device according to the sixth embodiment. Fig. 9 (b) is a schematic diagram of a part of the liquid ejection device according to the sixth embodiment.

[0021] Fig.10 (a) is an explanatory diagram of a modified example of the first embodiment. Fig.10 (b) is an explanatory diagram of a modified example of the third embodiment.

[0022] Fig.11 It is a schematic diagram of a part of the liquid ejection device of the comparative example.

[0023] Description of Reference Numerals

[0024] 1. Inkjet head (ejection head); 2. Ink cartridge (liquid cartridge); 30. Liquid circulation device; 31. Circulation path (first circulation path); 32. Circulation path (second circulation path); 203. Outlet (first port); 204. Return port (second port); 205. Return port (third port). DETAILED DESCRIPTION

[0025] Hereinafter, the illustrative embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following embodiments illustrate the preferred structures of the present disclosure by way of example, and for example, those skilled in the art can appropriately change the detailed structures to implement the present disclosure without departing from the main purpose of the present disclosure. In addition, for the drawings referred to in the description of the following embodiments, unless there are special remarks, the elements shown with the same figure numerals have the same functions. In addition, these drawings are schematically represented for the convenience of illustration and description, and are therefore not limited to being strictly consistent with the shape, size, configuration, etc. of the actual objects.

[0026] In this specification, the liquid processed in the liquid ejection device is sometimes described as "ink", but the ink of the embodiment is not limited to the liquid containing the recording material for forming text and images. For example, the ink can also be a liquid containing functional materials for forming functional films such as electrodes and filters, functional elements such as organic EL elements, and can also be a liquid containing insoluble solid components. In addition, sometimes the practice of ejecting liquid to impart it to an object is described as "recording", but the recording mentioned here is not necessarily limited to recording information such as text and images. For example, it also includes the practice of imparting to an object a liquid containing raw materials for manufacturing functional films, functional elements, three-dimensional molded objects, etc. In addition, sometimes the object to which the liquid is imparted is described as a "recording medium", but it is not limited to a medium for recording information such as text and images, and includes a component (such as a substrate) that serves as a base material for manufacturing functional films, functional elements, three-dimensional molded objects, etc.

[0027] [First embodiment]

[0028] Figure 11 is a schematic diagram of a liquid ejection device 100 according to a first embodiment. The liquid ejection device 100 includes an ink cartridge 2 as an example of a liquid cartridge. The ink cartridge 2 is a container capable of storing ink as an example of a liquid. In addition, the liquid ejection device 100 includes an inkjet head (hereinafter referred to as a "head") 1 as an example of an ejection head for ejecting liquid and a liquid circulation device 30.

[0029] The ink contains a solvent and an insoluble solid component. The sedimentation rate of the insoluble solid component is determined according to the particle size of the insoluble solid component, the density of the insoluble solid component, the density of the solvent, and the viscosity of the ink. In order to reduce the sedimentation of the insoluble solid component, a predetermined flow rate must be given to the circulating ink.

[0030] As the insoluble solid component of the ink, for example, TiO2 can be cited. When the insoluble solid component is TiO2, the central particle diameter of the insoluble solid component is 200nm, and the particle size distribution of the insoluble solid component is more than 100nm and less than 700nm. The main component of the ink is acrylic acid monomer. The concentration of the insoluble solid component is 7% by weight. At room temperature, the viscosity of the ink is 10mPa·s (shear rate is 1 1 / s).

[0031] In addition, the composition of the insoluble solid component, the particle size of the insoluble solid component, the viscosity of the ink, the main component of the ink, etc. are not limited to the above examples. For example, the particle size can be greater than 50nm and less than 2μm. In addition, the viscosity of the ink can be greater than 1mPa·s and less than 40mPa·s. In addition, the main component of the ink is determined according to the physical properties of the coating film and is not limited to acrylic monomers. For example, it can be methacrylic resin, epoxy resin, phenolic resin or polyurethane resin.

[0032] The head 1 has a plurality of nozzles (not shown) that eject ink droplets as liquid droplets, a common channel (not shown) that distributes ink from the ink cartridge 2 to each nozzle, and individual channels (not shown) that connect the common channel and the nozzles.

[0033] The liquid circulation device 30 includes a circulation flow path 31 as an example of a first circulation flow path and a circulation flow path 32 as an example of a second circulation flow path. The circulation flow paths 31 and 32 are each configured to include piping and the like. The circulation flow path 31 is a main circulation flow path of ink that returns from the ink cartridge 2 via the head 1 to the ink cartridge 2. The circulation flow path 32 is a secondary circulation flow path of ink that returns from the ink cartridge 2 to the ink cartridge 2 without passing through the head 1. The circulation flow path 32 is provided independently of the circulation flow path 31. That is, the circulation flow path 32 is not a flow path branched from the circulation flow path 31.

[0034] The circulation flow path 31 is a flow path that circulates the ink between the ink cartridge 2 and the head 1 to reduce the drying of the solvent contained in the ink from the nozzles and to reduce the sedimentation of the insoluble solid components in the pipe due to the stagnation of the ink.

[0035] The circulation flow path 31 has an outlet 201 for ink from the ink cartridge 2 and a return port 202 for returning the ink to the ink cartridge 2. The ink stored in the ink cartridge 2 is output from the outlet 201 to the circulation flow path 31, and is supplied to the head 1 through the circulation flow path 31. The remaining ink that is not ejected from the head 1 is returned to the ink cartridge 2 from the return port 202 through the circulation flow path 31. Thus, the ink circulates between the ink cartridge 2 and the circulation flow path 31. The outlet 201 is an example of a fourth port.

[0036] The liquid circulation device 30 has a pump 4 as an example of a first pump, a damper 5, and a filter 6 arranged in a circulation flow path 31. The pump 4 is a pump for delivering ink as a liquid. The pump 4 is, for example, a diaphragm pump, a pipeline pump, or a piston pump. The damper 5 is used to reduce the pulsation of the ink delivered by the pump 4. The filter 6 is used to remove foreign matter contained in the ink. In addition, a degassing component (not shown) for removing dissolved gas in the ink may also be provided in the circulation flow path 31.

[0037] The circulation flow path 32 has one or more outlets for the ink from the ink cartridge 2 and one or more return ports for the ink to return to the ink cartridge 2. The circulation flow path 32 preferably has two or more return ports. In the first embodiment, the circulation flow path 32 has an outlet 203 for the ink from the ink cartridge 2 and return ports 204 and 205 for the ink to return to the ink cartridge 2. The outlet 203 is an example of a first port, the return port 204 is an example of a second port, and the return port 205 is an example of a third port. The return port 205 is a port arranged at a position different from the return port 204.

[0038] The circulation flow path 32 includes a main flow path 33 and branch flow paths 34 and 35 which are arranged on the downstream side of the main flow path 33 and branched from the main flow path 33. The outlet 203 is included in the main flow path 33. The return port 204 is included in the branch flow path 34. The return port 205 is included in the branch flow path 35. The ink stored in the ink cartridge 2 is output from the outlet 203 to the main flow path 33 of the circulation flow path 32, and is returned from the return port 204 and the return port 205 to the ink cartridge 2 through the branch flow path 34 and the branch flow path 35. Thus, the ink circulates between the ink cartridge 2 and the circulation flow path 32.

[0039] The liquid circulation device 30 has a pump 14 as an example of a second pump, a damper 15, and a filter 16 arranged in a main flow path 33 of a circulation flow path 32. The pump 14 is a pump for delivering ink as a liquid. The pump 14 is, for example, a diaphragm pump, a pipeline pump, or a piston pump. The damper 15 is used to reduce the pulsation of the ink delivered by the pump 14. The filter 16 is used to remove foreign matter contained in the ink. In addition, a degassing component (not shown) for removing dissolved gas in the ink may also be provided in the circulation flow path 32.

[0040] In addition, the liquid circulation device 30 has a flow control valve 17, which is arranged at a branch portion where the main flow path 33 branches to the branch flow paths 34 and 35. The flow control valve 17 is, for example, a three-way valve having one input port and two output ports. The flow control valve 17 adjusts the flow rate of ink output to the branch flow paths 34 and 35 respectively relative to the flow rate of the input ink.

[0041] Furthermore, the liquid ejecting device 100 includes a liquid level sensor 40 and a control device 50 for controlling the entire liquid ejecting device 100 .

[0042] The liquid level sensor 40 is a sensor for detecting the height (liquid level) of the liquid surface in the ink cartridge 2. The control device 50 includes a CPU (not shown), a storage device (not shown), an input / output interface (not shown), etc., and can obtain a signal indicating a detection result from the liquid level sensor 40, and control the head 1, the pump 4, the pump 14, and the flow control valve 17.

[0043] Here, a liquid ejection device according to a comparative example will be described. Fig.11 FIG. 1 is a schematic diagram of a portion of a liquid ejection device of a comparative example. Fig.11 In the embodiment, the outlet 203X and the return port 204X of the secondary circulation flow path are both arranged at the bottom of the ink cartridge 2X. In the case of this comparative example, since the return port 204X is located at the lower side of the interior of the ink cartridge 2X, Fig.11 As shown in the left figure, the ink circulates only near the inner bottom surface of the ink cartridge 2X. Therefore, the concentration of the insoluble solid components of the ink on the lower side is higher than the concentration of the insoluble solid components of the ink on the upper side inside the ink cartridge 2X. In this way, the concentration of the insoluble solid components is uneven inside the ink cartridge 2X.

[0044] In the first embodiment, the ink output from the outlet 203 to the outside of the ink cartridge 2 flows in the circulation flow path 32 and returns to the inside of the ink cartridge 2 from the return port 204 provided above the outlet 203. By circulating the ink in this way, the ink inside the ink cartridge 2 is stirred, and the sedimentation of the insoluble solid components of the ink inside the ink cartridge 2 is reduced. As a result, the concentration non-uniformity of the insoluble solid components contained in the ink inside the ink cartridge 2 is reduced, and the ink having a uniform concentration of the insoluble solid components is supplied to the head 1 via the circulation flow path 31.

[0045] In addition, in the circulation flow path 32, the ink does not pass through the head 1 midway. Therefore, the ink can be circulated at a high speed in the circulation flow path 32 compared with the circulation flow path 31. The flow rate of the ink in the circulation flow path 32 is preferably 3 times or more of the flow rate of the ink in the circulation flow path 31. Thus, the sedimentation of the insoluble solid components of the ink inside the ink cartridge 2 can be effectively reduced. Thus, the concentration unevenness of the insoluble solid components contained in the ink inside the ink cartridge 2 can be effectively reduced.

[0046] Figure 2 (a)~ Figure 2 (c) is a schematic diagram of the ink cartridge 2 according to the first embodiment when viewed in the horizontal direction. Figure 2 (a) and Figure 2 The arrow indicating the rotation direction of the inside of the ink cartridge 2 in (b) indicates the direction of the convection of the ink. Here, a three-dimensional rectangular coordinate system of the X-axis, Y-axis and Z-axis based on the ink cartridge 2 is defined. The X-axis, Y-axis and Z-axis are orthogonal to each other. The directions of the arrows indicating the X-axis, Y-axis and Z-axis are set to the positive direction. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is the direction opposite to the gravity direction.

[0047] The positive direction of the X axis is set to +X direction, and the negative direction of the X axis is set to -X direction. The positive direction of the Y axis is set to +Y direction, and the negative direction of the Y axis is set to -Y direction. The positive direction of the Z axis is set to +Z direction, and the negative direction of the Z axis is set to -Z direction. That is, the -Z direction is the direction of gravity, and the +Z direction is the direction opposite to the gravity direction. The -Z direction is also the downward direction, and the +Z direction is also the upward direction or the height direction. Figure 2 (a)~ Figure 2 (c) is a schematic diagram of the ink cartridge 2 when the ink cartridge 2 is viewed along the Y-axis direction (+Y direction).

[0048] The return port 204 is provided above the outlet 203, that is, on the +Z direction side of the outlet 203. In other words, the outlet 203 is provided below the return port 204, that is, on the -Z direction side of the return port 204.

[0049] like Figure 2 As shown in (a), the region R1 and R2 formed by dividing the internal region of the ink cartridge 2 into two regions by the imaginary plane PZ are defined. The region R1 is the region on the +Z direction side relative to the imaginary plane PZ, that is, the upper half of the region in the Z-axis direction (+Z direction). The region R2 is the region on the -Z direction side relative to the imaginary plane PZ, that is, the lower half of the region in the Z-axis direction (+Z direction).

[0050] The virtual plane PZ is a virtual plane parallel to the XY plane and passes through the middle point between the apex in the Z-axis direction and the bottom point in the Z-axis direction of the ink cartridge 2. The apex in the ink cartridge 2 is the point (uppermost point) at which the value is the maximum in the Z-axis direction, and the bottom point in the ink cartridge 2 is the point (lowermost point) at which the value is the minimum in the Z-axis direction. In the spatial region inside the ink cartridge 2, the region above the virtual plane PZ is region R1, and the region below the virtual plane PZ is region R2.

[0051] The return port 204 of the circulation flow path 32 is arranged in the region R1, and the outlet 203 of the circulation flow path 32 is arranged in the region R2. Thus, the ink stored in the ink cartridge 2 is easily convected, and the ink in the ink cartridge 2 is effectively stirred, effectively reducing the sedimentation of the insoluble solid components contained in the ink.

[0052] In addition, if Figure 2 As shown in (b), the region R3 and R4 are defined by dividing the region inside the ink cartridge 2 by the imaginary plane PX. The region R3 is on the +X direction side with respect to the imaginary plane PX. The region R4 is on the -X direction side with respect to the imaginary plane PX.

[0053] The virtual plane PX is a virtual plane parallel to the YZ plane and passes through a midpoint between a point at which the value in the X-axis direction is the maximum and a point at which the value in the X-axis direction is the minimum inside the ink cartridge 2 .

[0054] The return port 204 of the circulation flow path 32 is arranged in the region R3, and the outlet 203 of the circulation flow path 32 is arranged in the region R4. Thus, the ink stored in the ink cartridge 2 is easily convected, and the ink in the ink cartridge 2 is effectively stirred, effectively reducing the sedimentation of the insoluble solid components contained in the ink.

[0055] Furthermore, the outlet 203 is more preferably arranged in a common region where the region R2 and the region R4 overlap, and the return port 204 is more preferably arranged in a common region where the region R1 and the region R3 overlap.

[0056] The return port 205 is preferably arranged below the return port 204, that is, at the -Z direction side of the return port 204. In other words, the return port 204 is preferably arranged above the return port 205, that is, at the +Z direction side of the return port 205. Thus, the ink stored in the ink cartridge 2 is easily convected, the ink in the ink cartridge 2 is effectively stirred, and the sedimentation of the insoluble solid components contained in the ink is effectively reduced.

[0057] In addition, the return port 205 is preferably disposed in the region R2. This facilitates convection of the ink stored in the ink cartridge 2, and the ink in the ink cartridge 2 is effectively stirred, thereby effectively reducing the sedimentation of insoluble solid components contained in the ink.

[0058] In addition, the return port 205 is preferably disposed in the region R3 . This facilitates convection of the ink stored in the ink cartridge 2 , effectively stirring the ink in the ink cartridge 2 , and effectively reducing the sedimentation of insoluble solid components contained in the ink.

[0059] Furthermore, the return port 205 is more preferably arranged in a common region where the region R2 and the region R3 overlap.

[0060] The interior of the ink cartridge 2 can be in various shapes such as a rectangular parallelepiped, a cylindrical shape, or a polygonal prism. The ink cartridge 2 has an inner top surface 21, an inner bottom surface 22, and an inner side surface 23 that define the inner area of ​​the ink cartridge 2. The inner side surface 23 is a surface extending along the Z-axis direction (+Z direction). When the interior of the ink cartridge 2 is in a rectangular parallelepiped or polygonal prism shape, the inner side surface 23 is, for example, a surface extending along the YZ plane. When the interior of the ink cartridge 2 is in a cylindrical shape, the inner side surface 23 is, for example, a side surface of a cylinder. The inner bottom surface 22 is, for example, a surface extending along the XY plane.

[0061] The outlet 203 is defined on the inner bottom surface 22 of the ink cartridge 2. The return port 204 is defined on the inner side surface 23 of the ink cartridge 2. As a result, the insoluble solid components accumulated in the lower part of the interior of the ink cartridge 2 are returned to the upper part of the interior of the ink cartridge 2, and the ink inside the ink cartridge 2 is effectively stirred, effectively reducing the sedimentation of the insoluble solid components contained in the ink. In addition, the ink inside the ink cartridge 2 is output from the outlet 203 in the -Z direction and returned from the return port 204 in the -X direction. As a result, the ink inside the ink cartridge 2 is stirred. Figure 2 The convection shown by the arrow in (a) rotates across regions R1 and R2, and produces Figure 2 The convection currents shown by arrows in (b) rotate across the regions R3 and R4. The convection currents of the ink effectively stir the ink inside the ink cartridge 2, and effectively reduce the sedimentation of the insoluble solid components contained in the ink.

[0062] The return port 205 is defined on the inner bottom surface 22 of the ink cartridge 2. Thus, the ink inside the ink cartridge 2 can be effectively generated by the ink returning from the return port 204 to the inside of the ink cartridge 2 and the ink returning from the return port 205 to the inside of the ink cartridge 2. Figure 2 (a) and Figure 2 The rotating convection shown by the arrow in (b) of FIG. 1 can effectively generate convection in the vertical and horizontal directions in the ink inside the ink cartridge 2. Therefore, the ink inside the ink cartridge 2 is effectively stirred, and the sedimentation of the insoluble solid components contained in the ink is effectively reduced.

[0063] The flow rate of the ink returned from the return ports 204 and 205 of the circulation flow path 32 to the inside of the ink cartridge 2 is greater than the flow rate of the ink returned from the return port 202 of the circulation flow path 31 to the inside of the ink cartridge 2. In other words, the flow rate of the ink returned from the return port 202 of the circulation flow path 31 to the inside of the ink cartridge 2 is less than the flow rate of the ink returned from the return ports 204 and 205 of the circulation flow path 32 to the inside of the ink cartridge 2. The outlet 201 and the return port 202 of the circulation flow path 31 are preferably arranged at positions that generate the convection of the ink in a direction that does not cancel the convection of the ink formed by the circulation flow path 32, that is, in a direction that assists.

[0064] The return port 202 is preferably arranged at a position above the outlet 201. The return port 202 is preferably arranged in the region R1, and the outlet 201 is preferably arranged in the region R2. The return port 202 is preferably defined on the inner side surface 23, and the outlet 201 is preferably defined on the inner bottom surface 22. In addition, the outlet 201 is preferably arranged between the outlet 203 and the return port 205, for example, at the center of the interior of the ink cartridge 2 in the X-axis direction and the Y-axis direction.

[0065] In addition, if Figure 2 (a) and Figure 2 As shown in (b), the return port 202 is preferably arranged below the return port 204, but is not limited thereto. The return port 202 may be arranged at the same height as the return port 204 or above the return port 204.

[0066] In addition, the outlet 203, the return port 204, and the return port 205 of the circulation flow path 32 are preferably arranged at the same position in the Y-axis direction, that is, at a position intersecting with an imaginary plane parallel to the XZ plane. Thus, convection of ink can be effectively generated inside the ink cartridge 2, and sedimentation of insoluble solid components can be effectively reduced.

[0067] The outlet 201 and the return port 202 of the circulation flow path 31 are also preferably arranged at the same positions in the Y-axis direction as the outlet 203, the return port 204, and the return port 205. This can effectively assist the convection of ink in the circulation flow path 31.

[0068] The flow rate of the ink in the circulation paths 31 and 32 is described. The flow rate of the ink in the circulation paths 31 and 32 is determined by the capacity of the pumps 4 and 14 and the inner diameter of the piping. When the flow rate of the ink generated by the operation of the pumps 4 and 14 is set to be constant, the smaller the inner diameter of the piping is, the greater the flow rate of the ink. The flow rate of the ink in the return ports 204 and 205 of the circulation path 32 is preferably greater than the flow rate of the ink in the return port 202 of the circulation path 31. Therefore, it is effective to set the return ports 204 and 205 to have an inner diameter smaller than that of the return port 202. On the other hand, when the flow rate of the ink is set to be constant, the smaller the inner diameter of the piping is, the less the flow rate of the ink that can flow in the piping is. Therefore, in order to obtain a predetermined flow rate at the return ports 202, 204, and 205, the appropriate inner diameter of the piping is determined based on the balance with the capacity of the pumps 4 and 14. In the pumps 4 and 14, as long as the flow rate of ink can be adjusted, the sizes of the pumps 4 and 14 can be made the same, and the liquid ejection device 100 can be miniaturized. Therefore, the inner diameter of the return ports 204 and 205 of the circulation flow path 32 is preferably smaller than the inner diameter of the return port 202 of the circulation flow path 31. In addition, in the circulation flow path 32, the inner diameter of the main flow path 33 is larger than the inner diameter of the branch flow paths 34 and 35.

[0069] The piping lengths of the circulation paths 31 and 32 are described. In the circulation path 31, since the flow velocity of the ink is relatively low, it is advantageous to reduce the sedimentation of the insoluble solid components by making the piping length as short as possible. On the other hand, since the flow velocity of the ink in the circulation path 32 is greater than the flow velocity of the ink in the circulation path 31, the piping length of the circulation path 32 may be longer than that of the circulation path 31. That is, the piping length of the circulation path 31 may be shorter than that of the circulation path 32.

[0070] The pressure of the nozzle (not shown) of the head 1 is controlled to be negative pressure. The control device 50 adjusts the pressure of the nozzle by controlling the pressure in the ink cartridge 2 to be negative pressure. The control device 50 can control the pressure in the ink cartridge 2 to be negative pressure using a gas pressure reducing pump (not shown). In addition, the method of controlling the pressure of the nozzle is not limited to this.

[0071] The liquid level sensor 40 is an example of a sensor that detects the remaining amount of ink (liquid) inside the ink cartridge 2. The control device 50 can control the flow control valve 17 disposed at the branch portion of the circulation flow path 32 according to the height of the ink in the ink cartridge 2 detected by the liquid level sensor 40 disposed inside the ink cartridge 2, that is, the remaining amount of ink in the ink cartridge 2, to adjust the amount of ink output from the return ports 204 and 205, respectively, so as to generate convection of ink in the ink cartridge 2.

[0072] In the first embodiment, if Figure 2 As shown in (c), the control device 50 is set with thresholds TH1, TH2, and TH3 corresponding to the height of the liquid level inside the ink cartridge 2. Threshold TH1 is greater than thresholds TH2 and TH3. Threshold TH2 is less than threshold TH1 and greater than threshold TH3. Threshold TH3 is less than thresholds TH1 and TH2.

[0073] Threshold TH1 is a value of a height corresponding to the amount of ink remaining inside the ink cartridge 2 being amount B1, for example, 400 ml. Amount B1 is an example of the first amount. Threshold TH2 is a value of a height corresponding to the amount of ink remaining inside the ink cartridge 2 being amount B2, for example, 200 ml. Amount B2 is an example of the second amount. Threshold TH3 is a value of a height corresponding to the amount of ink remaining inside the ink cartridge 2 being amount B3, for example, 50 ml. Amount B3 is an example of the third amount. Amount B1 is greater than amounts B2 and B3. Amount B2 is less than amount B1 and greater than amount B3. Amount B3 is less than amounts B1 and B2. Amounts B1, B2, and B3 are volumes. In addition, amounts B1, B2, and B3 may also be weights, in which case the sensor for detecting the remaining amount of ink is, for example, a weight sensor.

[0074] A method for manufacturing an article using a liquid ejecting method performed by the liquid ejecting device 100 will be described. Figure 3 1 is a flowchart of the operation of the liquid ejection device 100 according to the first embodiment. Figures 4 to 61 is an explanatory diagram of the operation of the liquid ejection device 100 according to the first embodiment. First, the ink inside the ink cartridge 2 is in an empty state.

[0075] In step S1, the control device 50 of the liquid ejecting device 100 starts the operation of the pump 14 of the circulation flow path 32. Figure 4 As shown, the control device 50 operates the pump 14 so that the flow rate of the ink becomes the flow rate A5 (for example, 150 ml / min, the inner diameter of the pipe of the main flow path 33 is 4 mm, and the flow rate is 199 mm / sec). The flow rate A5 is an example of the fifth flow rate.

[0076] In step S2, the control device 50 controls a valve (not shown) provided on the piping connecting the ink cartridge 2 and the main cartridge (not shown) to fill the ink cartridge 2 with a predetermined amount of ink (e.g., 500 ml) from the main cartridge. Figure 2 The amounts B1 to B3 shown in (c) are greater than the amounts B1 to B3 shown in (c). In addition, the amount of ink supplied to the ink cartridge 2 is the amount that does not overflow from the ink cartridge 2. When the ink cartridge 2 is filled with ink, the ink circulates between the ink cartridge 2 and the circulation path 32 by the operation of the pump 14.

[0077] In addition, the control device 50 controls the flow regulating valve 17 to adjust the flow rate of the ink returned from the return port 204 to the ink cartridge 2 to the flow rate A1 and adjust the flow rate of the liquid returned from the return port 205 to the ink cartridge 2 to the flow rate A2. The flow rate A1 is an example of the first flow rate, and the flow rate A2 is an example of the second flow rate. The flow rate A1 is greater than the flow rate A2. In addition, the flow rates A1, A2, and A5 are all greater than the flow rate A10 described later. In addition, the flow rate A5 is the total flow rate of the flow rates A1 and A2.

[0078] Step S3 is performed for a certain time T1, for example, 30 minutes. The processing of step S3 is called filtration. In addition, in step S3, the operation of the pump 4 provided in the circulation flow path 31 is in a stopped state, that is, the flow rate of the pump 4 is zero. In other words, the filtration of step S3 is performed in a state where the operation of the pump 4 is stopped. By operating the pump 14 arranged in the circulation flow path 32 for a time T1, the ink filled in the ink cartridge 2 flows in the circulation flow path 32 and passes through the filter 16, and the foreign matter contained in the ink is removed by the filter 16. The time T1 can be determined according to the particle size of the insoluble solid component of the ink, the filter particle size of the filter 16, the amount of ink input and the flow rate of the pump 14.

[0079] The purpose of filtering in step S3 is to prevent foreign matter from being supplied to the circulation path 31, that is, the head 1. Since the filter 6 is also provided in the circulation path 31 at a position upstream of the head 1, the filtering in step S3 serves as a pre-filter. In addition, by allowing the ink to circulate between the ink cartridge 2 and the circulation path 32 for a certain time T1, the concentration of the ink inside the ink cartridge 2 is uniformed.

[0080] In step S4 , the control device 50 starts the operation of the pump 4 of the circulation flow path 31 .

[0081] In step S5, the control device 50 operates the pump 4 so that the flow rate of the ink becomes flow rate A10 (for example, 50 ml / min, the inner diameter of the piping of the circulation flow path 31 is 4 mm, and the flow rate is 66 mm / sec). Flow rate A10 is a flow rate smaller than flow rate A5. This step S5 is performed for a certain time T2, for example, 30 minutes. The process of step S5 is also called filtration. In addition, the state of the pump 14 and the flow regulating valve 17 is maintained from step S3. That is, the flow rate of the pump 14 is flow rate A5, the flow rate of the ink returned from the return port 204 to the inside of the ink cartridge 2 is flow rate A1, and the flow rate of the ink returned from the return port 205 to the inside of the ink cartridge 2 is flow rate A2. At this time, for example, the flow rate A5 of the ink is 150 ml / min, and the flow rates A1 and A2 are 75 ml / min. When the inner diameter of the pipe of the main flow path 33 is 4 mm and the inner diameter of the pipes of the branch flow paths 34 and 35 is 3 mm, the flow velocities of the main flow path 33 and the branch flow paths 34 and 35 are 199 mm / sec, 177 mm / sec, and 177 mm / sec, respectively.

[0082] In step S6, the control device 50 starts ejecting ink from the head 1. The operation of the pumps 4 and 14 continues, and the head 1 ejects ink in a state where the flow rate of ink from the pump 4 is set to the flow rate A10 (steady state).

[0083] The control device 50 controls the flow rate regulating valve 17 to regulate the flow rate of ink returned from the return port 204 to the ink cartridge and the flow rate of ink returned from the return port 205 to the ink cartridge 2 according to the remaining liquid amount inside the ink cartridge 2. This will be described in detail below.

[0084] In step S7, the control device 50 determines whether the liquid level is below the threshold TH1 based on the detection result obtained from the liquid level sensor 40. The threshold TH1 is set to a value lower than the return port 204, for example, a value corresponding to the amount of ink remaining in the ink cartridge 2, which is B1 (400 ml).

[0085] If the answer of step S7 is "No", that is, if the remaining amount of ink in the ink cartridge 2 is greater than the amount B1, the flow rate of the pump 14 is maintained at the flow rate A5, the flow rate of the ink from the return port 204 is maintained at the flow rate A1, and the flow rate of the ink from the return port 205 is maintained at the flow rate A2. That is, the control device 50 controls the flow regulating valve 17 to maintain the flow rate of the pump 14 at the flow rate A5, maintain the flow rate of the ink from the return port 204 at the flow rate A1, and maintain the flow rate of the ink from the return port 205 at the flow rate A2.

[0086] If the answer of step S7 is "yes", that is, the amount of ink remaining in the ink cartridge 2 is less than the amount B1, the process proceeds to the following step S8. Figure 5 As shown, the control device 50 controls the flow regulating valve 17 to adjust the flow rate of the ink returned from the return port 204 to the ink cartridge 2 to a flow rate A3 which is smaller than the flow rate A1, and adjust the flow rate of the ink returned from the return port 205 to the ink cartridge 2 to a flow rate A4 which is larger than the flow rate A2. The flow rate A3 is an example of the third flow rate, and the flow rate A4 is an example of the fourth flow rate. The flow rate A4 is greater than the flow rate A3. In addition, the flows A3, A4, and A5 are all greater than the flow rate A10. In addition, the flow rate A5 is the total flow rate of the flow rate A3 and the flow rate A4. At this time, for example, the flow rate A5 of the ink is 150 ml / min, the flow rate A3 is 60 ml / min, and the flow rate A4 is 90 ml / min. When the inner diameter of the piping of the main flow path 33 is 4 mm, and the inner diameter of the piping of the branch flow paths 34 and 35 is 3 mm, the flow rates of the main flow path 33 and the branch flow paths 34 and 35 are 199 mm / sec, 141 mm / sec, and 212 mm / sec, respectively.

[0087] When the liquid level of the ink inside the ink cartridge 2 is higher than the return port 204, the ink returned from the return port 204 to the inside of the ink cartridge 2 has a greater effect of stirring the ink inside the ink cartridge 2. On the other hand, if the liquid level of the ink inside the ink cartridge 2 is lower than the return port 204, the stirring effect becomes smaller, so the amount of ink returned from the return port 205 on the lower side is increased to induce stirring inside the ink cartridge 2.

[0088] In step S9, the control device 50 determines whether the height of the liquid surface is less than or equal to the threshold value TH2 based on the detection result obtained from the liquid level sensor 40. The threshold value TH2 is set to a value corresponding to the height when the remaining amount of ink in the ink cartridge 2 is the amount B2 (200 ml), for example.

[0089] If the answer of step S9 is "No", that is, if the remaining amount of ink in the ink cartridge 2 is less than the amount B1 and greater than the amount B2, the flow rate of the pump 14 is maintained at the flow rate A5, the flow rate of the ink from the return port 204 is maintained at the flow rate A3, and the flow rate of the ink from the return port 205 is maintained at the flow rate A4. That is, the control device 50 controls the flow regulating valve 17 so that the flow rate of the pump 14 is maintained at the flow rate A5, the flow rate of the ink from the return port 204 is maintained at the flow rate A3, and the flow rate of the ink from the return port 205 is maintained at the flow rate A4.

[0090] If the answer of step S9 is "yes", that is, the amount of ink remaining in the ink cartridge 2 is less than the amount B2, the process proceeds to the following step S10. Figure 6As shown, the control device 50 controls the pump 14 to adjust the flow rate of the pump 14 to a flow rate A6 which is smaller than the flow rate A5. The flow rate A5 is, for example, 150 ml / min, and the flow rate A6 is, for example, 110 ml / min. The flow rate A6 is an example of the sixth flow rate. In addition, the flow rate A6 is greater than the flow rate A10.

[0091] Since the flow rate of the pump 14 is adjusted to a flow rate A6 that is smaller than the flow rate A5, the flow rate of the ink returned from the return port 204 to the ink cartridge 2 is reduced from the flow rate A3 to the flow rate A7, and the flow rate of the ink returned from the return port 205 to the ink cartridge 2 is reduced from the flow rate A4 to the flow rate A8. The flow rate A7 is smaller than the flow rate A3, and the flow rate A8 is smaller than the flow rate A4. In addition, the flow rate A6 is the total flow rate of the flow rates A7 and A8. At this time, for example, the flow rate A6 of the ink is 110 ml / min, and the flow rates A7 and A8 are 55 ml / min. When the inner diameter of the piping of the main flow path 33 is 4 mm and the inner diameter of the piping of the branch flow paths 34 and 35 is 3 mm, the flow rates of the main flow path 33 and the branch flow paths 34 and 35 are 199 mm / sec, 130 mm / sec, and 130 mm / sec, respectively.

[0092] When the remaining amount of ink in the ink cartridge 2 decreases to the amount B2, for example, 200 ml, the flow rate of the pump 14 decreases from the flow rate A5 to the flow rate A6, so that the pulsation of the ink liquid surface in the ink cartridge 2 decreases.

[0093] In step S11, the control device 50 determines whether the height of the liquid surface is less than or equal to the threshold value TH3 based on the detection result obtained from the liquid level sensor 40. The threshold value TH3 is set to a value corresponding to the height at which the remaining amount of ink in the ink cartridge 2 is the amount B3 (50 ml), for example.

[0094] If the answer of step S11 is "No", that is, if the remaining amount of ink in the ink cartridge 2 is less than the amount B2 and greater than the amount B3, the flow rate of the pump 14 is maintained at the flow rate A6, the flow rate of the ink from the return port 204 is maintained at the flow rate A7, and the flow rate of the ink from the return port 205 is maintained at the flow rate A8. That is, the control device 50 controls the flow regulating valve 17 so that the flow rate of the pump 14 is maintained at the flow rate A6, the flow rate of the ink from the return port 204 is maintained at the flow rate A7, and the flow rate of the ink from the return port 205 is maintained at the flow rate A8.

[0095] If the answer of step S11 is "yes", that is, if the amount of ink remaining in the ink cartridge 2 is less than the amount B3, the process proceeds to the following step S12. In step S12, the control device 50 stops the ejection of ink from the head 1 and stops the operation of the pump 4. In addition, the control device 50 operates the pump 14 so that the flow rate of the ink becomes the flow rate A5 (for example, 150 ml / min, the inner diameter of the pipe of the circulation flow path 31 is 4 mm, and the flow rate is 199 mm / sec), and the process returns to step S2.

[0096] In step S2, the control device 50 controls a valve (not shown) provided on the pipe connecting the ink cartridge 2 and the main cartridge (not shown) to replenish the ink from the main cartridge to the ink cartridge 2 by an amount (for example, 450 ml) less than a predetermined amount (for example, 500 ml) by an amount B3. In other words, the ink is replenished into the ink cartridge 2 so that the remaining amount of ink in the ink cartridge 2 becomes the predetermined amount.

[0097] According to the first embodiment, by making the flow rate of the ink in the circulation path 32 greater than the predetermined flow rate, the ink inside the ink cartridge 2 can be effectively stirred. On the other hand, by making the flow rate of the ink in the circulation path 31 less than the predetermined flow rate, the deviation can be reduced and the ink can be stably ejected from the head 1.

[0098] In addition, the ink can be convected in a wide range between the top and bottom of the ink cartridge 2, and the concentration unevenness of the insoluble solid components contained in the ink can be reduced in the ink cartridge 2. Therefore, the ink with reduced concentration unevenness can be stably ejected from the head 1. As a result, the physical properties of the ink ejected from the head 1 are stable, and the deviation of the ejection state (e.g., ejection speed and ejection amount) of the ink ejected from the head 1 can be reduced, for example, an article including a functional film or a functional element can be manufactured with a good yield.

[0099] (Example 1)

[0100] Embodiment 1 is an experimental example of an experiment using a liquid ejection device 100 corresponding to the first embodiment. In Embodiment 1, an ink is used in which 7% by weight of TiO2 is added as an insoluble solid component to an acrylic monomer as a main component. As for the particle size of TiO2 added to the ink, the center particle diameter is 200nm, and the particle size distribution is greater than 100nm and less than 700nm. The shape of the interior of the ink cartridge 2 is a rectangular parallelepiped. The inner diameter of the piping of the circulation flow path 31 is set to 4mm, and the inner diameter of the piping of the circulation flow path 32 is set to 4mm in the main flow path 33 and 3mm in the branch flow paths 34 and 35.

[0101] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0102] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 150 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0103] Under the conditions exemplified in the first embodiment, Figure 3 The flow chart shown in the figure shows that the liquid ejection device 100 was used for 10 consecutive days. The droplet velocity and ink landing accuracy from the head 1 were evaluated, and the initial evaluation and the evaluation after 10 days were compared. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0104] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0105] After the liquid ejection device 100 was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0106] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0107] As described above, based on the experimental results of the first embodiment, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0108] [Second embodiment]

[0109] Hereinafter, unless otherwise specified, elements denoted with reference numerals common to the first embodiment have substantially the same structure and function as those described in the first embodiment, and the differences from the first embodiment will be mainly described.

[0110] Figure 7 (a) is a partial schematic diagram of the liquid ejection device of the second embodiment. In the second embodiment, a return port 206 provided in the ink cartridge 2 is added to the circulation flow path 32 of the first embodiment. The other structures are the same as those of the liquid ejection device 100 of the first embodiment, and the description thereof is omitted.

[0111] In the second embodiment, the circulation flow path 32 has one outlet 203 and three return ports 204, 205, and 206 branched from the main flow path 33. Specifically, the return port 204 is formed in one branch flow path 34 branched from the main flow path 33. The other branch flow path 35 is further branched into two branch flow paths 36 and 37 on the downstream side. The return port 205 is formed in the branch flow path 36, and the return port 206 is formed in the branch flow path 37. That is, the circulation flow path 32 has the return ports 205 and 206 as two or more third ports.

[0112] The return ports 205 and 206 are defined in the inner bottom surface 22 of the ink cartridge 2. In the inner bottom surface 22, the outlet 201 and the outlet 203 are defined between the return port 205 and the return port 206. That is, in the inner bottom surface 22, the return ports 205 and 206 are defined outside the outlets 201 and 203. Specifically, in the inner bottom surface 22, the outlet 201 is defined between the outlet 203 and the return port 206, and the outlet 203 is defined between the outlet 201 and the return port 205.

[0113] Since the two return ports 205 and 206 as two or more third ports are defined on the inner bottom surface 22 , convection of ink can be effectively generated inside the ink cartridge 2 , and sedimentation of insoluble solid components can be effectively reduced.

[0114] In addition, since insoluble solid components tend to settle to the end of the inner bottom surface 22 , the return ports 205 , 206 are arranged outside the outlets 201 , 203 in the inner bottom surface 22 , thereby effectively reducing the insoluble solid components from settling to the inner bottom surface 22 .

[0115] (Example 2)

[0116] Example 2 is an experimental example of an experiment using a liquid ejection device corresponding to the second embodiment. In Example 2, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm or more and 700 nm or less. The shape of the interior of the ink cartridge 2 was a rectangular parallelepiped.

[0117] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0118] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 150 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0119] In Example 2, under the conditions illustrated in the first embodiment, that is, under the conditions of Example 1, Figure 3 The flow chart shown in the figure shows that the liquid ejection device was used for 10 consecutive days. The droplet velocity and ink landing accuracy from the head 1 were evaluated, and the initial evaluation and the evaluation after 10 days were compared. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0120] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0121] After the liquid ejection device was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0122] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0123] As described above, based on the experimental results of Example 2, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0124] [Third Embodiment]

[0125] The third embodiment of the present disclosure is described. Hereinafter, unless otherwise specified, elements marked with reference numerals common to the first embodiment or the second embodiment have substantially the same structure and function as the elements described in the first embodiment or the second embodiment, and the parts different from the first embodiment or the second embodiment are mainly described.

[0126] Figure 7 (b) is a partial schematic diagram of the liquid ejection device of the third embodiment. In the third embodiment, an ink cartridge 2B is provided instead of the ink cartridge 2. In addition, in the third embodiment, as in the second embodiment, the circulation flow path 32 has an outlet 203 and return ports 204 to 206. The other structures are the same as those of the liquid ejection device 100 of the first embodiment, and the description thereof is omitted.

[0127] The ink cartridge 2B has an inner top surface 21, an inner bottom surface 22, an inner side surface 23 and an inclined surface 24 that define the inner region of the ink cartridge 2B. The inner side surface 23 is a surface extending along the Z-axis direction (+Z direction). The inner bottom surface 22 is a surface extending along the XY plane, for example.

[0128] The inclined surface 24 is disposed between the inner side surface 23 and the inner bottom surface 22. The inclined surface 24 is connected to the inner bottom surface 22 and is inclined upward from the inner bottom surface 22.

[0129] The return port 204 and the return port 202 are defined on the inner side surface 23. The return port 205 and the return port 206 are defined on the inclined surface 24 of the ink cartridge 2. The outlet 201 and the outlet 203 are defined on the inner bottom surface 22.

[0130] The outlet 201 and the outlet 203 are defined between the return port 205 and the return port 206. That is, the return ports 205 and 206 are defined outside the outlets 201 and 203 in the inner bottom surface 22.

[0131] Since the two return ports 205 and 206 as two or more third ports are defined on the inclined surface 24 , convection of the ink can be effectively generated inside the ink cartridge 2 , and sedimentation of the insoluble solid content can be effectively reduced.

[0132] In addition, compared with the horizontal surface, the insoluble solid components are less likely to settle on the inclined surface 24. Since the inclined surface 24 is inclined toward the inner bottom surface 22, the insoluble solid components that settle on the inclined surface 24 are guided to the inner bottom surface 22. Moreover, the insoluble solid components guided to the inner bottom surface 22 are sucked into the outlet 203 arranged on the inner bottom surface 22, and are returned to the inside of the ink cartridge 2 from the return port 204. As a result, the concentration unevenness of the insoluble solid components of the ink inside the ink cartridge 2 can be reduced.

[0133] Compared with the horizontal surface, the insoluble solid components are less likely to settle on the inclined surface 24, but by configuring the return ports 205 and 206 on the inclined surface 24, the insoluble solid components can be effectively reduced from settling on the inclined surface 24. In addition, since the outlet 203 is configured on the inner bottom surface 22, the insoluble solid components can be effectively reduced from settling on the inner bottom surface 22.

[0134] (Example 3)

[0135] Example 3 is an experimental example of an experiment conducted using a liquid ejection device corresponding to the third embodiment. In Example 3, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm or more and 700 nm or less.

[0136] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0137] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 170 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0138] In Example 3, under conditions different from those illustrated in the first embodiment, that is, different from those in Example 1, the Figure 3 The flow chart shown uses the liquid ejection device for 10 consecutive days. In step S1, the flow rate of pump 14 is set to 170 ml / min as flow rate A5. In step S3, time T1 is set to 10 minutes. In step S4, the flow rate of pump 4 is set to 55 ml / min as flow rate A10. In step S5, time T2 is set to 60 minutes. Threshold TH1 is set to a value at a height equivalent to 400 ml as amount B1. Threshold TH2 is set to a value at a height equivalent to 200 ml as amount B2. Threshold TH3 is set to a value at a height equivalent to 50 ml as amount B3. In step S10, the flow rate of pump 14 is set to 100 ml / min as flow rate A6.

[0139] The droplet velocity and ink landing accuracy from the head 1 were evaluated and compared between the initial evaluation and the evaluation after 10 days. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0140] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0141] After the liquid ejection device 100 was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0142] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0143] As described above, based on the experimental results of Example 3, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0144] [Fourth embodiment]

[0145] Hereinafter, unless otherwise specified, elements marked with reference numerals common to the first to third embodiments have substantially the same structure and function as the elements described in the first to third embodiments, and the parts different from the first to third embodiments will be mainly described.

[0146] Figure 7 (c) is a partial schematic diagram of the liquid ejection device of the fourth embodiment. In the fourth embodiment, as in the second embodiment, the circulation flow path 32 has an outlet 203 and return ports 204 to 206. However, unlike the second embodiment, in the fourth embodiment, the return ports 204 to 206 are not defined in the ink cartridge 2, but are defined in the piping extending into the interior of the ink cartridge 2.

[0147] In the following, the branch flow path 34 has a pipe 301 extending into the interior of the ink cartridge 2 and having a return port 204 formed therein. The pipe 301 is an example of a first pipe. The branch flow path 36 has a pipe 302 extending into the interior of the ink cartridge 2 and having a return port 205 formed therein. The branch flow path 37 has a pipe 303 extending into the interior of the ink cartridge 2 and having a return port 206 formed therein. The pipes 302 and 303 are each an example of a second pipe. That is, in the fourth embodiment, the circulation flow path 32 has two or more second pipes.

[0148] The relative positional relationship of the return ports 204 to 206 in the height direction is as described in the second embodiment. That is, the return port 204 is arranged at a position higher than the return ports 205 and 206. In addition, the outlet 201, the outlet 203, and the return port 202 are arranged at the same positions as in the second embodiment. The pipes 301 to 303 are arranged so as to penetrate the upper member of the ink cartridge 2, for example.

[0149] The ink returned from the return ports 205 and 206 to the ink cartridge 2 hits the inner bottom surface 22 of the ink cartridge 2 and flows horizontally, and then becomes a convection current rising along the inner surface 23. The ink returned from the return port 204 to the ink cartridge 2 causes the upper ink to convect downward.

[0150] As described above, according to the fourth embodiment, it is possible to generate ink convection inside the ink cartridge 2 as in the second embodiment, to effectively stir the ink inside the ink cartridge 2, and to effectively reduce the sedimentation of the insoluble solid components contained in the ink inside the ink cartridge 2. Thus, the concentration unevenness of the insoluble solid components contained in the ink inside the ink cartridge 2 can be reduced.

[0151] Furthermore, since the ink returns toward the inner bottom surface 22 , it is possible to effectively reduce the accumulation of insoluble solid components included in the ink on the inner bottom surface 22 .

[0152] (Example 4)

[0153] Example 4 is an experimental example of an experiment using a liquid ejection device corresponding to the fourth embodiment. In Example 4, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm or more and 700 nm or less. The shape of the interior of the ink cartridge 2 was a rectangular parallelepiped.

[0154] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0155] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 150 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0156] In Example 4, under the conditions illustrated in the first embodiment, that is, under the conditions of Example 1, Figure 3 The flow chart shown in the figure shows that the liquid ejection device was used for 10 consecutive days. The droplet velocity and ink landing accuracy from the head 1 were evaluated, and the initial evaluation and the evaluation after 10 days were compared. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0157] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0158] After the liquid ejection device was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0159] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0160] As described above, based on the experimental results of Example 4, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0161] [Fifth embodiment]

[0162] Hereinafter, unless otherwise specified, elements marked with reference numerals common to the first to fourth embodiments have substantially the same structure and function as the elements described in the first to fourth embodiments, and the parts different from the first to fourth embodiments will be mainly described.

[0163] Figure 8 (a) is a schematic diagram of a liquid ejecting device 100D according to the fifth embodiment. The liquid ejecting device 100D includes a head 1 , an ink cartridge 2 , a liquid circulation device 30D, and a control device 50 . Figure 8 (b) is a schematic diagram of the ink cartridge 2 according to the fifth embodiment when viewed in the horizontal direction.

[0164] The liquid circulation device 30D has a circulation flow path 31 as an example of a first circulation flow path and a circulation flow path 32D as an example of a second circulation flow path. The circulation flow path 31 has the same structure as described in the first embodiment. The pump 4, the damper 5, the filter 6, and the head 1 are arranged in the circulation flow path 31.

[0165] The circulation flow path 32D has two or more first ports provided at the outlets 203 and 207 of the ink cartridge 2 as outlets of the ink from the ink cartridge 2. The circulation flow path 32D also has a return port 204 provided at the ink cartridge 2 as a second port as a return port for returning the liquid to the liquid cartridge.

[0166] The circulation flow path 32D includes a main flow path 33 and two sub-flow paths 38 and 39 provided on the upstream side of the main flow path 33. The outlet 203 is formed at the upstream end of the sub-flow path 38, and the outlet 207 is formed at the upstream end of the sub-flow path 39. The return port 204 is formed at the downstream end of the main flow path 33. The filter 16, the pump 14, and the damper 15 are arranged in the main flow path 33.

[0167] The outlets 203 and 207 are defined on the inner bottom surface 22 of the ink cartridge 2 and are arranged at positions which are about 1 / 4 of the length of the inner bottom surface 22 in the X-axis direction away from the inner side surface 23 of the ink cartridge 2 .

[0168] In the above structure, as in the first embodiment, the ink output from the outlets 203 and 207 to the outside of the ink cartridge 2 flows in the circulation flow path 32D and returns to the inside of the ink cartridge 2 from the return port 204 provided above the outlets 203 and 207. By circulating the ink in this way to stir the ink inside the ink cartridge 2, it is possible to reduce the sedimentation of the insoluble solid components of the ink inside the piping of the circulation flow path 31 and inside the ink cartridge 2. As a result, the concentration unevenness of the insoluble solid components contained in the ink inside the ink cartridge 2 is reduced.

[0169] In addition, the outlet 201 is arranged at the center of the inner bottom surface 22 of the ink cartridge 2. The outlet 201 of the circulation flow path 31 is arranged between the outlet 203 and the outlet 207 of the circulation flow path 32D. According to such an arrangement, the ink with reduced concentration unevenness of the insoluble solid content convecting inside the ink cartridge 2 can be stably supplied to the head 1.

[0170] (Example 5)

[0171] Example 5 is an experimental example of an experiment using a liquid ejection device 100D corresponding to the fifth embodiment. In Example 5, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm or more and 700 nm or less. The shape of the interior of the ink cartridge 2 was a rectangular parallelepiped.

[0172] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0173] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 130 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0174] In Example 5, under the conditions illustrated in the first embodiment, that is, under the conditions of Example 1, Figure 3 The flow chart shown in the figure shows that the liquid ejection device was used for 10 consecutive days. The droplet velocity and ink landing accuracy from the head 1 were evaluated, and the initial evaluation and the evaluation after 10 days were compared. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0175] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0176] After the liquid ejection device was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0177] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0178] As described above, based on the experimental results of Example 5, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0179] [Sixth embodiment]

[0180] Hereinafter, unless otherwise specified, elements marked with reference numerals common to the first to fifth embodiments have substantially the same structure and function as the elements described in the first to fifth embodiments, and the parts different from the first to fifth embodiments will be mainly described.

[0181] Fig. 9 (a) and Fig. 9 (b) is a partial schematic diagram of the liquid ejection device of the sixth embodiment. Fig. 9 (a) is a schematic diagram of the ink cartridge 2 obtained by observing the ink cartridge 2 in the -Z direction. Fig. 9 (b) is a schematic diagram of the ink cartridge 2 when the ink cartridge 2 is viewed in the +Y direction.

[0182] In the sixth embodiment, as in the first embodiment, the circulation flow path 32 has an outlet 203 and return ports 204 and 205. However, in the sixth embodiment, the positions of the return ports 204 and 205 are different from those in the first embodiment. The return port 204 is an example of a second port, and the return port 205 is an example of a third port. The outlets 201 and 203 are arranged on the inner bottom surface 22 of the ink cartridge 2.

[0183] The return port 204 and the return port 205 are arranged at positions and orientations that are point-symmetrical with respect to a center point C0 of the ink cartridge 2. The center point C0 is an example of a predetermined point.

[0184] For example, Fig. 9 (a) and Fig. 9As shown in (b), the return port 204 is inclined in the direction of an acute angle relative to the -X direction, in the direction of an acute angle relative to the +Y direction, and in the direction of an acute angle relative to the +Z direction. In contrast, the return port 205 is inclined in the direction of an obtuse angle relative to the -X direction (in the direction of an acute angle relative to the +X direction), in the direction of an obtuse angle relative to the +Y direction (in the direction of an acute angle relative to the -Y direction), and in the direction of an obtuse angle relative to the +Z direction (in the direction of an acute angle relative to the -Z direction). In this way, the return port 205 is inclined in the opposite direction to the return port 204.

[0185] Therefore, inside the ink cartridge 2, the ink returns from each return port 204, 205 in a direction inclined relative to the imaginary vertical plane and the imaginary horizontal plane, so the ink convects in a vortex shape when viewed from a direction horizontal to the liquid surface and a direction vertical to the liquid surface. Therefore, the ink inside the ink cartridge 2 is stirred, and the sedimentation of the insoluble solid components of the ink can be reduced inside the piping of the circulation flow path 31 and inside the ink cartridge 2. As a result, the concentration unevenness of the insoluble solid components contained in the ink inside the ink cartridge 2 can be reduced.

[0186] (Example 6)

[0187] Example 6 is an experimental example of an experiment conducted using a liquid ejection device corresponding to the sixth embodiment. In Example 6, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm or more and 700 nm or less. The shape of the interior of the ink cartridge 2 was a rectangular parallelepiped.

[0188] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 50 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0189] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 150 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0190] In Example 6, under the conditions illustrated in the first embodiment, that is, under the conditions of Example 1, Figure 3 The flow chart shown in the figure shows that the liquid ejection device was used for 10 consecutive days. The droplet velocity and ink landing accuracy from the head 1 were evaluated, and the initial evaluation and the evaluation after 10 days were compared. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0191] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0192] After the liquid ejection device was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0193] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0194] As described above, based on the experimental results of Example 6, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0195] (Example 7)

[0196] Example 7 is an experimental example in which an experiment is conducted using a liquid ejection device corresponding to Embodiment 1. However, the head 1 of Example 7 has a lower resolution than the head 1 of Example 1, that is, the number of nozzles is smaller than that of the head 1 of Example 1.

[0197] The flow rate of ink in the piping of the circulation flow path 31 for stably ejecting ink to the head 1 is calculated as the sum of the flow rates required for one nozzle. That is, the smaller the number of nozzles in the head 1, the smaller the flow rate of the circulation flow path 31 for stably ejecting ink to the head 1. Therefore, the inner diameter of the piping of the circulation flow path 31 is set to 4 mm in Example 1, but is set to 2.5 mm in this Example 7. Since the flow rate of the circulation flow path 31 passing through the head is reduced, the flow rate of the circulation flow path 32 is also reduced, and the inner diameter of the piping of the circulation flow path 32 is set to 3 mm in the main flow path 33 and 2 mm in the branch flow paths 34 and 35.

[0198] In Example 7, an ink was used in which 7% by weight of TiO2 was added as an insoluble solid component to an acrylic monomer as a main component. The particle size of the TiO2 added to the ink had a central particle diameter of 200 nm and a particle size distribution of 100 nm to 700 nm. The shape of the interior of the ink cartridge 2 was a rectangular parallelepiped.

[0199] A diaphragm pump manufactured by KNF was used as the pump 4, and the flow rate was 12 ml / min. A pulsation reduction damper FPD manufactured by KNF was used as the damper 5. A filter with a filtration size of 5 μm was selected as the filter 6.

[0200] A diaphragm pump manufactured by KNF was used as the pump 14, and the flow rate was 85 ml / min. The same damper as the damper 5 was used as the damper 15. The same filter as the filter 6 was used as the filter 16.

[0201] In Example 7, under conditions different from those illustrated in the first embodiment, that is, different from those in Example 1, the Figure 3 The flow chart shown in the figure shows that the liquid ejection device is used for 10 consecutive days. That is, in step S1, the flow rate of the pump 14 is set to 85 ml / min as the flow rate A5. The branch flow paths 34 and 35 are respectively set to the same flow rate (42.5 ml / min). When the inner diameter of the pipe of the main flow path 33 is 3 mm and the inner diameter of the pipe of the branch flow paths 34 and 35 is 2 mm, the flow rates of the main flow path 33 and the branch flow paths 34 and 35 are 200 mm / sec, 225 mm / sec, and 225 mm / sec, respectively.

[0202] In step S4, the flow rate of the pump 4 is set to 12 ml / min as the flow rate A10. When the inner diameter of the pipe of the circulation flow path 31 is 2.5 mm, the flow velocity of the circulation flow path 31 is 41 mm / sec.

[0203] In step S8, flow rate A5 is maintained at 85 ml / min, and flow rate A3 and flow rate A4 are increased by the ratio of flow rate A4 from the same flow rate. The ratio is the same as in Example 1, flow rate A4 is set to 1.5 times flow rate A3, flow rate A3 is set to 34 ml / min, and flow rate A4 is set to 51 ml / min. At this time, the flow velocity corresponding to flow rate A3 is 180 mm / sec, and the flow velocity corresponding to flow rate A4 is 270 mm / sec.

[0204] In the head 1 with low resolution, if the remaining amount of ink in the ink cartridge 2 decreases, it is easy to be affected by the pulsation of the ink in the ink cartridge 2. Therefore, in step S10, the flow rate of the pump 14 is set to 60 ml / min as the flow rate A6, and the flow rates A7 and A8 are set to 30 ml / min respectively. At this time, the flow rates of the main flow path 33 and the branch flow paths 34 and 35 are 141 mm / sec, 159 mm / sec, and 159 mm / sec respectively. In Example 7, the setting conditions other than the above-mentioned flow rates are the same as those in Example 1.

[0205] The droplet velocity and ink landing accuracy from the head 1 were evaluated and compared between the initial evaluation and the evaluation after 10 days. As a result, it was confirmed that there was no change in the evaluation between the initial evaluation and the evaluation after 10 days.

[0206] The droplet velocity is obtained by observing the ink ejected from the head 1 with a high-speed camera. The ink landing accuracy is obtained by measuring the position of the ink landed on the substrate to measure the deviation from the target position and calculating the deviation from continuous images of the high-speed camera.

[0207] After the liquid ejection device was operated for 10 consecutive days, the concentration of the insoluble solid content of the ink remaining in the ink cartridge 2 was measured using a thermogravimetric analyzer. As a result, it was confirmed that the concentration of the insoluble solid content was within the measurement accuracy range of the measuring device and had not changed since the beginning.

[0208] Furthermore, the ink applied to the substrate was dried and the performance of the coating film was evaluated (transmittance measurement and reflectance measurement). As a result, it was confirmed that there was no difference between the performance of the film formed on the 10th day and the performance of the film formed initially.

[0209] As described above, based on the experimental results of Example 7, it was confirmed that the sedimentation of the insoluble solid components contained in the ink can be reduced inside the ink cartridge 2 , and the ink droplets can be stably ejected from the head 1 .

[0210] [Modifications]

[0211] The present disclosure is not limited to the above-described embodiments, and the above-described embodiments can be modified in many ways within the technical concept of the present disclosure. Fig.10 (a) is an explanatory diagram of a modified example of the first embodiment, Fig.10 (b) is an explanatory diagram of a modified example of the third embodiment.

[0212] In addition, Fig.10 (a) and Fig.10 (b) shows the outlet 203 and the return port 204 of the circulation flow path 32. Fig.10 (a) and Fig.10 In (b), the illustration of the outlet and return port of the circulation flow path 31 is omitted.

[0213] like Fig.10 As shown in (a), the outlet 203 is arranged at the lower part of the ink cartridge 2, and the return port 204 is arranged at the upper part of the ink cartridge 2. In a modified example of the first embodiment, the circulation flow path 32 does not have the return port 205. In this case, it is also possible to reduce the sedimentation of the insoluble solid components contained in the ink inside the ink cartridge 2, thereby reducing the uneven concentration of the insoluble solid components. However, the flow of the ink becomes to move approximately straight from the return port 204 to the outlet 203. Therefore, it is more preferable to configure the return port 205 as in the first embodiment.

[0214] In addition, if Fig.10As shown in (b), the outlet 203 is arranged at the lower part of the ink cartridge 2B, and the return port 204 is arranged at the upper part of the ink cartridge 2B. In a modified example of the third embodiment, the circulation flow path 32 does not have the return port 205. In this case, it is also possible to reduce the sedimentation of the insoluble solid components contained in the ink inside the ink cartridge 2B, thereby reducing the uneven concentration of the insoluble solid components. However, inside the ink cartridge 2B, sometimes the concentration of the insoluble solid components on the inclined surface 24 is slightly higher than the concentration in other parts. Therefore, it is preferable to configure the return port 205 on the inclined surface 24 as in the third embodiment.

[0215] As described above, according to the present disclosure, convection of the liquid is easily induced inside the liquid box, and the occurrence of uneven concentration of components of the liquid inside the liquid box can be reduced.

[0216] The effects described in this embodiment are merely the best effects produced by the embodiments of the present disclosure, and the effects of the embodiments of the present disclosure are not limited to the effects described in this embodiment. In addition, at least two of the above-mentioned multiple embodiments and multiple modifications may be combined.

Claims

1. A liquid ejection device, characterized in that: The liquid ejection device comprises: Liquid boxes; a spray head that sprays liquid; and A liquid circulation device that circulates the liquid, The liquid circulation device comprises: a first circulation flow path that returns from the liquid cartridge via the ejection head to the liquid cartridge; and a second circulation channel that returns from the liquid box to the liquid box without passing through the ejection head, The second circulation flow path includes a first port serving as an outlet of the liquid from the liquid box and a second port serving as a return port for returning the liquid to the liquid box. The second port is provided above the first port.

2. The liquid ejection device according to claim 1, characterized in that: The first port is provided in a lower half region in the height direction of the interior of the liquid box. The second port is provided in a region of an upper half in the height direction of the interior of the liquid cartridge.

3. The liquid ejection device according to claim 1, characterized in that: The second circulation channel includes a third port different from the second port, which serves as a return port for returning the liquid to the liquid cartridge.

4. The liquid ejection device according to claim 3, characterized in that: The third port is provided at a lower side than the second port.

5. The liquid ejection device according to claim 3, characterized in that: The third port is provided in a region of the lower half in the height direction of the interior of the liquid box.

6. The liquid ejection device according to claim 1, characterized in that: The liquid box has an inner bottom surface, The first port is defined on the inner bottom surface of the liquid box.

7. The liquid ejection device according to claim 3, characterized in that: The liquid box has an inner bottom surface, The first port and the third port are defined on the inner bottom surface of the liquid box.

8. The liquid ejection device according to claim 7, characterized in that: The first circulation flow path includes a fourth port serving as an outlet for the liquid from the liquid box. The fourth port is arranged between the first port and the third port.

9. The liquid ejection device according to claim 3, characterized in that: The liquid box has an inner bottom surface and an inclined surface, the inclined surface is connected to the inner bottom surface and is inclined upward from the inner bottom surface. The first port is defined on the inner bottom surface of the liquid box, The third port is defined on the inclined surface of the liquid box.

10. The liquid ejection device according to claim 9, characterized in that: The first circulation flow path includes a fourth port serving as an outlet for the liquid from the liquid box. The fourth port is defined on the inner bottom surface.

11. The liquid ejection device according to claim 7, characterized in that: The second circulation flow path has two or more third ports.

12. The liquid ejection device according to claim 1, characterized in that: The liquid box has an inner side extending in a height direction, The second port is defined on the inner side surface of the liquid box.

13. The liquid ejection device according to claim 1, characterized in that: The second circulation flow path includes a first pipe in which the second port is formed, and the first pipe extends into the interior of the liquid box.

14. The liquid ejection device according to claim 3, characterized in that: The second circulation flow path includes a second pipe in which the third port is formed, and the second pipe extends into the interior of the liquid box.

15. The liquid ejection device according to claim 14, characterized in that: The second circulation flow path includes two or more second pipes.

16. The liquid ejection device according to claim 1, characterized in that: The second circulation flow path includes two or more first ports.

17. The liquid ejection device according to claim 1, characterized in that: The second circulation channel includes a third port different from the second port, which serves as a return port for returning the liquid to the liquid box. The second port and the third port are arranged at positions and orientations that are point-symmetrical about a predetermined point.

18. The liquid ejection device according to claim 1, characterized in that: The liquid circulation device comprises: a first pump disposed in the first circulation flow path; and a second pump disposed in the second circulation flow path, In a state where the first pump and the second pump are operating, a flow rate of the liquid returning from the second circulation flow path to the liquid cartridge is faster than a flow rate of the liquid returning from the first circulation flow path to the liquid cartridge.

19. The liquid ejection device according to claim 3, characterized in that: The liquid ejection device also includes a control device, The liquid circulation device includes a flow control valve, which is arranged in the second circulation flow path at a branching portion where the main flow path branches to the second port and the third port, and the control device can control the flow control valve. The control device controls the flow rate regulating valve to regulate a flow rate of the liquid returned from the second port to the liquid cartridge and a flow rate of the liquid returned from the third port to the liquid cartridge according to a residual amount of liquid in the liquid cartridge.

20. The liquid ejection device according to claim 19, characterized in that: The control device controls: When the remaining amount of liquid in the liquid box is greater than the first amount, the flow rate of the liquid returned from the second port to the liquid box is set to the first flow rate, and the flow rate of the liquid returned from the third port to the liquid box is set to the second flow rate, When the remaining amount of liquid inside the liquid box is less than the first amount, the flow rate of the liquid returned from the second port to the liquid box is set to a third flow rate smaller than the first flow rate, and the flow rate of the liquid returned from the third port to the liquid box is set to a fourth flow rate larger than the second flow rate.

21. The liquid ejection device according to claim 20, characterized in that: The liquid circulation device has a second pump, and the second pump is arranged in the second circulation flow path. The control device can control the second pump. The control device controls: When the remaining amount of liquid in the liquid box is larger than a second amount that is smaller than the first amount, the flow rate of the second pump is set to a fifth flow rate, When the remaining amount of liquid in the liquid cartridge is equal to or less than the second amount, the flow rate of the second pump is set to a sixth flow rate that is smaller than the fifth flow rate.

22. The liquid ejection device according to claim 21, characterized in that: The control device replenishes the liquid into the liquid cartridge when the remaining amount of the liquid in the liquid cartridge is equal to or less than a third amount that is smaller than the second amount.

23. The liquid ejection device according to claim 1, characterized in that: The liquid is ink containing an insoluble solid component.

24. A liquid ejection method, characterized in that: The liquid is ejected from the liquid cartridge using the liquid ejection device according to any one of claims 1 to 23.

25. The liquid ejection method according to claim 24, characterized in that: The liquid is a liquid containing a functional material for forming a functional film or a functional element.

26. A method for manufacturing an article, characterized in that: By the liquid ejecting method according to claim 25, a liquid containing a raw material of a functional thin film or a functional element is ejected toward a substrate.

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