Liquid discharge device and liquid set to be used in the same

Abstract

To provide a technique that can suppress liquid in a nozzle from being diluted.SOLUTION: A liquid discharge device is provided with: a head for discharging first liquid containing solid contents from a nozzle toward a medium; a cap that can move between a contacting position where the cap contacts the head in order to cover the nozzle and a separating position where the cap separates from the head; a first tank which stores second liquid different from the first liquid and is connected to the cap through a first flow path; a second tank that is connected to the cap through a second flow path different from the first flow path; and a control part. A density of the second liquid is higher than a density of the first liquid. The control part can execute a first supply process for supplying the second liquid from the first tank through the first flow path into the cap and a first discharging process for discharging the second liquid from the cap through the second flow path into the second tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This specification discloses a technique relating to a liquid ejection device that ejects liquid toward a medium. [Background technology]

[0002] Patent Document 1 discloses a liquid ejection device. In this liquid ejection device, the humidity near the nozzles of the head is maintained within a predetermined range by covering the head with a cap filled with moisturizing liquid. This prevents the nozzles from drying out during storage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2014-008639 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection device described above, when the moisturizing liquid stored in the cap comes into contact with the nozzle surface, there is a risk that the ink in the nozzle may be diluted by the moisturizing liquid. This specification provides a technology that can prevent the liquid in the nozzle from being diluted. [Means for solving the problem]

[0005] This specification discloses a liquid ejection device. The liquid ejection device includes a head for ejecting a first liquid containing solids from nozzles toward a medium; a cap movable between a contact position where the cap contacts the head to cover the nozzles and a spaced position where the cap is spaced from the head; a first tank for storing a second liquid different from the first liquid and connected to the cap via a first flow path; a second tank connected to the cap via a second flow path different from the first flow path; and a control unit. The density of the second liquid is greater than that of the first liquid. The control unit is capable of performing a first supply process for supplying the second liquid from the first tank to the cap via the first flow path and a first discharge process for discharging the second liquid from the cap to the second tank via the second flow path.

[0006] According to the above configuration, since the second liquid has a higher density than the first liquid, a greater gravitational force acts on the second liquid than on the first liquid. Therefore, even if the second liquid supplied into the cap comes into contact with the nozzle surface, the first liquid and the second liquid in the nozzle can be prevented from mixing. This prevents the first liquid in the nozzle from being diluted.

[0007] A computer program for realizing the liquid ejection device and a computer-readable recording medium storing the computer program are also novel and useful. A method executed by the liquid ejection device is also novel and useful. Also novel and useful is a liquid set used in the liquid ejection device, the liquid set including a first liquid and a second liquid. [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows the external configuration of an image recording device 10. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. [Figure 4]3 is a diagram showing the connection relationship between an ink tank 48 and a discharge module 36. FIG. [Figure 5] 3 is a cross-sectional view of the dispensing module 36 and the cap 60 with the cap 60 in the contact position. [Figure 6] 3 is a cross-sectional view of the dispensing module 36 and the cap 60 with the cap 60 in the spaced apart position. [Figure 7] 10 is a flowchart of a storage mode process. [Figure 8] 10 is a flowchart of a maintenance process. DETAILED DESCRIPTION OF THE INVENTION

[0009] (External configuration of image recording device 10) An image recording device 10 according to an embodiment will be described with reference to the drawings. The image recording device 10 is a device that ejects ink toward a sheet 2 according to an inkjet recording method to record an image on the sheet 2. The image recording device 10 is used by being placed on a table. However, in other embodiments, the image recording device 10 may be used by being placed on the floor or on a rack.

[0010] In this specification, each direction is defined based on the state in which the image recording device 10 is installed. As shown in Fig. 1, the up-down direction is defined with the installation surface side of the image recording device 10 as the bottom, the front-rear direction is defined with the side where the discharge port 20 of the image recording device 10 is provided as the front, and the left-right direction is defined when looking at the image recording device 10 from the front.

[0011] As shown in Figures 1 and 2, the image recording device 10 includes a housing 12. The housing 12 includes an upper housing 14 and a lower housing 16. The upper housing 14 is rotatably supported by the lower housing 16 around a rotation axis 18 extending in the left-right direction. This allows the upper housing 14 to move between a closed position (see Figures 1 and 2) and an open position (not shown). A first internal space S1 is formed by the upper housing 14, and a second internal space S2 is formed by the lower housing 16.

[0012] The image recording device 10 further includes a discharge opening 20. The discharge opening 20 is provided on the front surface 16a of the lower housing 16. The discharge opening 20 is a through-hole that penetrates the lower housing 16 in the front-to-rear direction. A sheet 2 (see FIG. 2) on which an image has been recorded is discharged from the discharge opening 20.

[0013] 1, the image recording device 10 further includes an operation unit 22. The operation unit 22 is an interface that allows the user to input various information to the image recording device 10, and includes, for example, a touch screen and buttons. The operation unit 22 is provided on the front surface 14a of the upper housing 14. The user can use the operation unit 22 to input instructions to turn the power of the image recording device 10 on and off, instructions to switch the operating mode, and the like.

[0014] (Internal configuration of image recording device 10) 2, the image recording device 10 further includes a holder 24, a tensioner 26, two pairs of conveying rollers 28, and a control unit 30. The control unit 30 is communicatively connected to each unit of the image recording device 10 and controls the operation of each unit. For ease of explanation, each component housed inside the housing 12 is illustrated in FIG. 2, but the components do not necessarily have to be located at positions corresponding to those illustrated in FIG. 2.

[0015] The holder 24 supports the roll 4 on which the long sheet 2 is wound in a circular shape. The holder 24 is disposed at the rear of the second internal space S2. The holder 24 is rotated by a conveyance motor (not shown). As the holder 24 rotates, the roll 4 supported by the holder 24 rotates.

[0016] The tensioner 26 is disposed above the holder 24. The tensioner 26 has an outer peripheral surface 26a against which the sheet 2 abuts. The sheet 2 pulled out from the roll 4 is curved along the outer peripheral surface 26a and fed forward.

[0017] Each of the two conveying roller pairs 28 includes a conveying roller 28a and a pinch roller 28b. The conveying roller 28a comes into contact with the pinch roller 28b to form a nip 6. The nip 6 is disposed at a position generally equal to the upper end of the outer circumferential surface 26a of the tensioner 26 in the vertical direction. Each of the two conveying roller pairs 28 is rotated by a conveying motor (not shown). Each of the two conveying roller pairs 28 rotates while nipping the sheet 2, thereby conveying the sheet 2 sent out from the tensioner 26 to the discharge port 20. The number and arrangement of the conveying roller pairs 28 are not particularly limited.

[0018] A conveying path 100 along which the sheet 2 is conveyed is formed between the holder 24 and the discharge port 20. When the sheet 2 passes through this conveying path 100, an image is recorded on the sheet 2.

[0019] 2 and 3, the image recording device 10 further includes a head 32. The head 32 is disposed above the transport path 100. The head 32 includes a frame 34 and a plurality of ejection modules 36a, 36b, and 36c. The frame 34 supports the plurality of ejection modules 36a, 36b, and 36c.

[0020] The discharge module 36a is disposed at a distance from the discharge module 36b in the left-right direction. The discharge module 36c is disposed at a distance from the discharge modules 36a and 36b in the front-rear direction. Hereinafter, the multiple discharge modules 36a, 36b, and 36c may be collectively referred to simply as "discharge modules 36."

[0021] As shown in FIG. 4, the image recording device 10 further includes an ink tank 48, a first pump 54, and flow paths 52 and 56. The ejection module 36 includes a plurality of nozzles 38, a manifold 40, an inlet port 42, and an outlet port 44. Each nozzle 38 opens in a nozzle surface 46 of the ejection module 36. The nozzle surface 46 is a surface extending in the front-rear and left-right directions. Each nozzle 38 is connected to the manifold 40. One end of the manifold 40 is connected to an ink tank 48 that stores ink via the inlet port 42 and a flow path 52. The other end of the manifold 40 is connected to the flow path 56 via the outlet port 44. When the control unit 30 drives the first pump 54 provided in the flow path 52, ink is supplied from the ink tank 48 to the manifold 40 via the inlet port 42. Then, when a piezoelectric element (not shown) corresponding to each nozzle 38 is driven, the ink in the manifold 40 is ejected to the outside through each nozzle 38. In this way, each nozzle 38 ejects ink toward the sheet 2 passing through the transport path 100, thereby recording an image on the sheet 2. A valve (not shown) is provided in the flow path 56, and when the valve is opened, the ink in the manifold 40 is discharged to the outside.

[0022] (ink) The ink contains resin particles, a coloring material, an organic solvent, a surfactant, and a solvent (or dispersion medium). The ink is an aqueous ink in which the resin particles, the coloring material, and the organic solvent are dissolved in a solvent or dispersed in a dispersion medium.

[0023] The ink has wettability to hydrophobic recording media such as coated paper, plastic, film, and OHP sheets. However, the ink is not limited thereto, and may be suitable for image recording on recording media other than hydrophobic recording media such as plain paper, glossy paper, and matte paper. Coated paper is, for example, plain paper made primarily of pulp, such as high-grade printing paper or medium-grade printing paper, to which a coating agent has been applied in order to improve smoothness, whiteness, gloss, etc. Specific examples include high-grade coated paper and medium-grade coated paper. Coated paper generally has lower absorbency than plain paper.

[0024] The resin particles may contain, for example, at least one of methacrylic acid and acrylic acid as a monomer, and commercially available products may be used. The resin particles may further contain, for example, styrene, vinyl chloride, etc. as a monomer. The resin particles may be contained in, for example, an emulsion. The emulsion is composed of, for example, resin particles and a dispersion medium (e.g., water, etc.). The resin particles are not dissolved in the dispersion medium, but are dispersed in the dispersion medium within a specific particle size range. Examples of resin particles include acrylic acid-based resins, maleic acid-based ester resins, vinyl acetate-based resins, carbonate-based resins, polycarbonate-based resins, styrene-based resins, ethylene-based resins, polyethylene-based resins, propylene-based resins, polypropylene-based resins, urethane-based resins, polyurethane-based resins, polyester-based resins, and copolymer resins thereof.

[0025] The resin particles may be made of a resin having a glass transition temperature (Tg) in the range of 0° C. to 200° C. The glass transition temperature (Tg) may be, for example, 20° C. to 180° C., or, for example, 30° C. to 150° C.

[0026] The emulsion may be, for example, a commercially available product, such as "Superflex (registered trademark) 870" (Tg: 78°C) and "Superflex (registered trademark) 150" (Tg: 40°C) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., "Mowinyl (registered trademark) DM774" (Tg: 33°C) manufactured by Japan Coating Resins Co., Ltd., and "Hiros-X (registered trademark) KE-1062" (Tg: 112°C) and "Hiros-X (registered trademark) QE-1042" (Tg: 69°C) manufactured by Seiko PMC Corporation.

[0027] The resin particles have an average particle size of, for example, 30 nm to 200 nm. The average particle size can be measured as an arithmetic mean diameter using, for example, a dynamic light scattering particle size distribution analyzer "LB-550" manufactured by Horiba, Ltd.

[0028] The content (R) of resin particles in the total amount of ink is, for example, in the range of 0.1% by weight to 30% by weight, for example, in the range of 0.5% by weight to 20% by weight, or for example, in the range of 1.0% by weight to 15.0% by weight. One type of resin particles may be used alone, or two or more types may be used in combination.

[0029] The colorant is a pigment that can be dispersed in water using, for example, a pigment dispersing resin (resin dispersant). Examples of colorants include carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium oxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments, polycyclic pigments, dye lake pigments, nitro pigments, nitroso pigments, and aniline black daylight fluorescent pigments. Examples of azo pigments include azo lake pigments, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of polycyclic pigments include phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Examples of dye lake pigments include basic dye lake pigments and acid dye lake pigments.

[0030] The solid content of the colorant in the total amount of ink is not particularly limited and can be appropriately determined depending on, for example, the desired optical density or saturation. The solid content of the colorant is, for example, in the range of 0.1% by weight to 20.0% by weight, and for example, in the range of 1.0% by weight to 15.0% by weight. The solid content of the colorant is the weight of the pigment only and does not include the weight of the resin particles. One type of colorant may be used alone, or two or more types may be used in combination.

[0031] The solid content of the resin particles and colorant in the total amount of ink is, for example, in the range of 0.2% by weight to 20% by weight, or in the range of 1% by weight to 15% by weight, or in the range of 3% by weight to 14% by weight, or in the range of 6% by weight to 13% by weight.

[0032] The organic solvent is not particularly limited, and any organic solvent can be used. Examples of organic solvents include propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, ethylene glycol, 1,2-butanediol, propylene glycol monobutyl ether, dipropylene glycol monopropyl ether, triethylene glycol monobutyl ether, 1,2-hexanediol, and 1,6-hexanediol, as well as glycol ethers having a propylene oxide group. Other examples of organic solvents include alkyl alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Other examples include alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol. Other examples include lower alkyl ethers of alkylene glycols such as glycerin, ethylene glycol monomethyl (or ethyl, propyl, butyl) ether, diethylene glycol monomethyl (or ethyl, propyl, butyl) ether, triethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, tetraethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, propylene glycol monomethyl (or ethyl, propyl, butyl) ether, dipropylene glycol monomethyl (or ethyl, propyl, butyl) ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl (or ethyl, propyl, butyl) ether, and tetrapropylene glycol monomethyl (or ethyl) ether. Other examples include N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.

[0033] The content of organic solvent in the total amount of ink is, for example, 50% by weight or less, such as 40% by weight or less, such as 30% by weight or less, or such as 20% by weight or less, of organic solvent that exists as a liquid at 25°C.

[0034] The water is preferably ion-exchanged water or pure water. The water content of the total ink is, for example, in the range of 15% to 95% by weight, or, for example, in the range of 25% to 85% by weight. The water content may be, for example, the remainder of the other components.

[0035] The ink may further contain known additives as needed. Examples of additives include surfactants, pH adjusters, viscosity adjusters, surface tension adjusters, preservatives, antifungals, leveling agents, antifoaming agents, light stabilizers, antioxidants, nozzle drying inhibitors, polymer components such as emulsions, and dyes. The surfactant may further include cationic surfactants, anionic surfactants, or nonionic surfactants. These surfactants may be commercially available products. Examples of commercially available products include "Olfine (registered trademark) E1010," "Olfine (registered trademark) E1006," "Olfine (registered trademark) E1004," "Silface SAG503A," and "Silface SAG002" manufactured by Nissin Chemical Industry Co., Ltd. The surfactant content of the total ink is, for example, 5% by weight or less, 3% by weight or less, or 0.1% by weight to 2% by weight. Examples of viscosity adjusters include polyvinyl alcohol, cellulose, and water-soluble resins.

[0036] The ink can be prepared, for example, by uniformly mixing resin particles, a coloring material, an organic solvent, water, and, if necessary, other additives, using a known method, and then removing any insoluble matter using a filter or the like.

[0037] (Configuration of caps 60a, 60b, and 60c) As shown in FIG. 2, the image recording device 10 further includes a support base 58 and a plurality of caps 60a, 60b, and 60c. The support base 58 supports the plurality of caps 60a, 60b, and 60c. Each of the caps 60a, 60b, and 60c can face a corresponding one of the ejection modules 36a, 36b, and 36c in the vertical direction. Note that the cap 60a is not depicted in the cross section shown in FIG. 2. Hereinafter, the plurality of caps 60a, 60b, and 60c may be collectively referred to simply as "caps 60." Note that the number and arrangement of the ejection modules 36 are not particularly limited. Furthermore, the number and arrangement of the caps 60 can be changed as appropriate to match the number and arrangement of the ejection modules 36.

[0038] As shown in FIGS. 5 and 6 , the cap 60 has a bottom surface 62 and four side surfaces 64 extending upward from the outer periphery of the bottom surface 62. A lip 66 is provided at the upper end of each side surface 64. The cap 60 is made of an elastic material such as rubber or silicone. As shown in FIG. 5 , the cap 60 is configured to be movable between a contact position where it contacts the head 32 (more specifically, the nozzle surface 46 of the ejection module 36 provided in the head 32) and a separation position where it is separated from the head 32 (nozzle surface 46), as shown in FIG. 6 . The support base 58 is configured to be movable by, for example, a drive mechanism such as a motor being controlled by the control unit 30. The cap 60 moves between the contact position and the separation position by moving together with the support base 58. When the cap 60 is positioned at the contact position, the lip 66 of the cap 60 contacts the nozzle surface 46 (see FIG. 5 ). As a result, the nozzle 38 is covered by the cap 60, and an internal space 80 is formed. When the cap 60 is in the separated position, the lip 66 of the cap 60 is separated from the nozzle face 46 (see FIG. 6). This opens the nozzle 38 from the internal space 80 within the cap 60.

[0039] (Configuration for supplying and discharging storage liquid) As shown in FIGS. 2, 4 to 6, the image recording device 10 further includes a storage liquid tank 68, a flow path 70, and a second pump 72. The storage liquid tank 68 stores storage liquid. The storage liquid is used to moisturize the nozzle 38 and to clean the inside of the cap 60. The storage liquid tank 68 is connected to the cap 60 via the flow path 70. The flow path 70 is provided with a second pump 72. When the second pump 72 is driven by the control unit 30, the storage liquid is supplied from the storage liquid tank 68 into the cap 60 via the flow path 70.

[0040] The image recording device 10 further includes a waste liquid tank 74, a flow path 76, and a third pump 78. The waste liquid tank 74 is connected to the cap 60 via the flow path 76. The flow path 76 is provided with the third pump 78. When the third pump 78 is driven by the control unit 30, the liquid inside the cap 60 is discharged from the cap 60 via the flow path 76 to the waste liquid tank 74.

[0041] (Storage solution) The storage liquid contains a water-soluble polymer, a water-soluble organic solvent, a surfactant, and water. The density of the storage liquid is greater than the density of the ink. Note that the density of the storage liquid may be greater than the density of the ink, and the specific value of the density of the storage liquid is not particularly limited.

[0042] The water-soluble polymer is dissolved in water, which is a solvent. Any water-soluble polymer can be used without any particular limitations. Examples of water-soluble polymers include polyvinylpyrrolidone and polyethylene glycol. Other water-soluble polymers include polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acids, styrene-acrylic acid copolymers, and acrylic acid-acrylic acid ester copolymers. Commercially available water-soluble polymers may be used. Examples of commercially available products include JONCRYL (registered trademark) manufactured by BASF, AQUALIC (registered trademark) manufactured by Nippon Shokubai Co., Ltd., and ARON (registered trademark) manufactured by Toagosei Co., Ltd. The water-soluble polymer preferably contains an aromatic alkyl group or a lactam group in its structure. The weight-average molecular weight of the water-soluble polymer is, for example, in the range of 8,000 to 20,000, or, for example, in the range of 8,500 to 15,000.

[0043] The water-soluble organic solvent is not particularly limited, and any suitable solvent can be used. Examples of water-soluble organic solvents include ethylene oxide, propylene glycol, ethylene glycol, 1,2-butanediol, propylene glycol propyl ether, dipropylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and 1,6-hexanediol, with glycol ethers having an ethylene oxide group being preferred. Other examples of organic solvents include alkyl alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Other examples include alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol. Other examples include lower alkyl ethers of alkylene glycols such as glycerin, ethylene glycol monomethyl (or ethyl, propyl, butyl) ether, diethylene glycol monomethyl (or ethyl, propyl, butyl) ether, triethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, tetraethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, propylene glycol monomethyl (or ethyl, propyl, butyl) ether, dipropylene glycol monomethyl (or ethyl, propyl, butyl) ether, tripropylene glycol monomethyl (or ethyl, propyl, butyl) ether, and tetrapropylene glycol monomethyl (or ethyl) ether. Other examples include N-methyl-2-pyrrolidone, 2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.

[0044] The water-soluble organic solvent may be used alone or in combination of two or more. The content of the water-soluble organic solvent in the total amount of the storage solution is, for example, in the range of 1% by weight to 50% by weight, and for example, in the range of 3% by weight to 35% by weight.

[0045] The surfactant is not particularly limited, and anionic surfactants, cationic surfactants, or nonionic surfactants can be used. Commercially available surfactants may be used. Examples of commercially available anionic surfactants include Sanol (registered trademark) manufactured by Lion Corporation, Emal (registered trademark) manufactured by Kao Corporation, and Sandet (registered trademark) and Viewlite (registered trademark) manufactured by Sanyo Chemical Industries, Ltd. One type of anionic surfactant may be used alone, or two or more types may be used in combination. The content of the anionic surfactant in the total amount of the storage solution is, for example, in the range of 0.01% by weight to 10% by weight, and, for example, in the range of 0.1% by weight to 10% by weight.

[0046] The surfactant contained in the storage liquid may contain one or more of anionic surfactants, cationic surfactants, and nonionic surfactants. From the viewpoint of the cleaning effect of the storage liquid on the cap 60, it is preferable that the polarity of the surfactant contained in the storage liquid is the same as the polarity of the ink. For example, if the charge of the solids or additives contained in the ink is anionic or nonionic, it is preferable that the storage liquid contain an anionic surfactant or a nonionic surfactant, and it is particularly preferable that the storage liquid contain an anionic surfactant.

[0047] The water is preferably ion-exchanged water or pure water. The water content of the total amount of the storage solution is, for example, 10% by mass or more and 90% by mass or less, or, for example, 20% by mass or more and 80% by mass or less. The water content may be, for example, the balance of other components.

[0048] The storage solution may further contain known additives as needed. Examples of additives include wetting agents, pH adjusters, viscosity adjusters, surface tension adjusters, and antifungal agents. Examples of viscosity adjusters include polyvinyl alcohol, cellulose, and water-soluble resins.

[0049] The storage solution can be prepared, for example, by uniformly mixing a water-soluble polymer, a water-soluble organic solvent, a surfactant, and water by a known method.

[0050] (Operation mode) The image recording device 10 is configured to be able to selectively operate in one of an image recording mode, a storage mode, and a maintenance mode. However, the image recording device 10 may also be able to operate in modes other than these modes. The image recording mode is a mode for ejecting ink from the ink tank 48 toward the sheet 2 to record an image on the sheet 2. The storage mode is a mode for covering the nozzles 38 with the caps 60 to prevent the nozzles 38 from drying out. That is, in the storage mode, ink is not ejected toward the sheet 2. The maintenance mode is a mode for preventing ink from adhering in the nozzles 38 and for resolving ink ejection abnormalities. The following describes the storage process executed by the control unit 30 when the image recording device 10 operates in the storage mode, and the maintenance process executed by the control unit 30 when the image recording device 10 operates in the maintenance mode.

[0051] (Storage processing; Figure 7) The storage process will be described with reference to FIG. 7. When a first transition condition is satisfied while the image recording device 10 is operating in the image recording mode, the control unit 30 switches the image recording device 10 to the storage mode and executes the storage process of FIG. 7. The first transition condition is satisfied when a period during which ink is not ejected from the nozzles 38 exceeds a predetermined period (e.g., one day). The first transition condition is also satisfied when an operation to turn off the power of the image recording device 10 is performed on the operation unit 22. In other words, the first transition condition is satisfied when the image recording device 10 is not used for a relatively long period of time. With this configuration, when the first transition condition is satisfied, the storage mode process of FIG. 7 is automatically started. Note that, in another embodiment, the first transition condition may be satisfied in only one of the above two cases.

[0052] In S10, the control unit 30 moves the cap 60 from the separated position (see FIG. 6) to the contact position (see FIG. 5). As a result, the lip 66 of the cap 60 contacts the nozzle face 46, and the nozzles 38 are covered by the cap 60.

[0053] In S12, the control unit 30 executes a first supply process. In the first supply process, the control unit 30 drives the second pump 72 to supply storage liquid from the storage liquid tank 68 into the cap 60 via the flow path 70. In the first supply process, for example, as shown in FIG. 5, the storage liquid is supplied in an amount that is approximately 90% of the volume of the cap 60 (i.e., the internal space 80). Therefore, after the storage liquid is supplied, the liquid surface of the storage liquid does not contact the nozzle surface 46, and a space is formed between the two. As described above, because the lip 66 of the cap 60 contacts the nozzle surface 46, an internal space 80 is formed within the cap 60, defined by the cap 60 and the nozzle surface 46. By supplying the storage liquid to the internal space 80, it is possible to prevent the nozzle 38 from drying out, even without bringing the nozzle surface 46 into contact with the storage liquid.

[0054] In S14, the control unit 30 determines whether a predetermined time has elapsed since the first supply process was executed. The predetermined time is, for example, one week. If the control unit 30 determines that the predetermined time has elapsed (YES in S14), the process proceeds to S16, and if the control unit 30 determines that the predetermined time has not elapsed (NO in S14), the process proceeds to S18.

[0055] In S16, the control unit 30 executes a refilling process. In the refilling process, the control unit 30 drives the second pump 72 to refill the storage liquid from the storage liquid tank 68 into the cap 60 via the flow path 70. After a predetermined time has passed since the first supplying process was executed, the storage liquid decreases due to evaporation. Therefore, by executing the refilling process, the amount of storage liquid in the cap 60 can be maintained within a predetermined range. This prevents the nozzles 38 from drying out after a predetermined time has passed since the first supplying process was executed. For example, if the ink contains a relatively large amount of solids (resin particles and coloring material), the ink is likely to solidify when the ink solvent evaporates. The technology of this embodiment is particularly useful when such ink is used. Furthermore, since the refilling process is executed at a specific timing after the first supplying process is executed, the amount of storage liquid in the cap 60 can be maintained within a predetermined range without requiring any additional components, such as a liquid level sensor.

[0056] In S18, the control unit 30 determines whether a second transition condition for transitioning the image recording device 10 from the storage mode to the image recording mode has been satisfied. The second transition condition is satisfied when an operation for transitioning the image recording device 10 from the storage mode to the image recording mode is performed on the operation unit 22. The second transition condition is also satisfied when an operation for turning on the power of the image recording device 10 is performed on the operation unit 22. Note that, in another embodiment, the second transition condition may be satisfied in only one of the above two cases. If the control unit 30 determines that the second transition condition has been satisfied (YES in S18), the control unit 30 proceeds to S20, and if the control unit 30 determines that the second transition condition has not been satisfied (NO in S18), the control unit 30 returns to S14.

[0057] In S20, the control unit 30 executes a first discharge process. In the first discharge process, the control unit 30 drives the third pump 78 to discharge the storage liquid from inside the cap 60 through the flow path 76 to the waste liquid tank 74.

[0058] In S22, the control unit 30 moves the cap 60 from the contact position to the separated position, and ends the storage process, whereby the image recording device 10 transitions from the storage mode to the image recording mode.

[0059] Because the storage process is performed as described above, the cap 60 is filled with storage liquid, preventing the nozzles 38 from drying out. However, for example, there is a possibility that the image recording device 10 may be moved or that a person may accidentally touch the image recording device 10. In this case, the liquid level of the storage liquid in the cap 60 may move, causing the storage liquid to come into contact with the nozzle surface 46. If the storage liquid has the same density as the ink or a density lower than that of the ink, the ink in the nozzles 38 may mix with the storage liquid, diluting the ink in the nozzles 38. As a result, the image may be recorded with diluted ink during the next printing operation. To prevent this from happening, in this embodiment, the storage liquid has a density higher than that of the ink. Therefore, a greater gravitational force acts on the storage liquid than on the ink. Therefore, even if the storage liquid supplied into the cap 60 comes into contact with the nozzle surface 46, mixing of the ink in the nozzles 38 with the storage liquid can be prevented. This prevents the ink in the nozzles 38 from being diluted.

[0060] (Maintenance process; Figure 8) Next, the maintenance process will be described with reference to FIG. 8. When the flushing condition or the purging condition is satisfied, the control unit 30 transitions the image recording device 10 from the image recording mode or the storage mode to the maintenance mode, and executes the maintenance process of FIG. 8. The flushing condition is satisfied when an operation to execute a flushing process on the image recording device 10 is performed on the operation unit 22. The flushing condition is also satisfied when a predetermined time has passed since the previous flushing process was performed while the image recording device 10 is operating in the image recording mode. The flushing process is a process for preventing ink from solidifying in the nozzles 38. The purging condition is satisfied when an operation to execute a purging process on the image recording device 10 is performed on the operation unit 22. The purging condition is also satisfied when an ink ejection abnormality is detected by a sensor (not shown). The purging process is a process for eliminating the ink ejection abnormality.

[0061] In S30, the control unit 30 drives the third pump 78 and / or a piezoelectric element (not shown) to perform a discharge process for discharging ink from the nozzles 38. The amount of ink discharged in the discharge process for the flushing process is less than the amount of ink discharged in the discharge process for the purge process. In particular, in this embodiment, when the image recording device 10 is shifted from the image recording mode to the maintenance mode to perform the flushing process, the control unit 30 performs the discharge process with the cap 60 maintained in the separated position. On the other hand, when the image recording device 10 is shifted from the image recording mode to the maintenance mode to perform the purge process, the control unit 30 moves the cap 60 from the separated position to the contact position and performs the discharge process with the cap 60 in contact with the nozzle surface 46.

[0062] In S32, the control unit 30 determines the amount of ink ejected in the ejection process of S30. As described above, the flushing process ejects a smaller amount of ink than the purging process. Therefore, when the ejection process for the flushing process is performed in S30, the control unit 30 determines that the amount of ink ejected is small, and when the ejection process for the purging process is performed in S30, the control unit 30 determines that the amount of ink ejected is large. Note that the control unit 30 may determine the amount of ink ejected by using a sensor to detect the amount of ink actually ejected in the ejection process.

[0063] In S34, the control unit 30 executes a third discharge process. In the third discharge process, the control unit 30 drives the third pump 78 to discharge the ink in the cap 60 to the waste liquid tank 74 via the flow path 76. This allows the ink ejected into the cap 60 to be discharged to the waste liquid tank 74 prior to cleaning the inside of the cap 60, which will be described later. Therefore, the amount of storage liquid required to clean the inside of the cap 60 can be reduced.

[0064] In S36, the control unit 30 executes a second supply process. In the second supply process, the control unit 30 moves the cap 60 to the contact position and drives the second pump 72 to supply storage liquid from the storage liquid tank 68 into the cap 60 via the flow path 70. This allows ink adhering to the inside of the cap 60 to be cleaned with the storage liquid. In S36, the control unit 30 determines the amount of storage liquid to be supplied in the second supply process based on the ink ejection amount determined in S32. Specifically, if it is determined in S32 that the ink ejection amount is small, i.e., if an ejection process for a flushing process has been performed, the control unit 30 supplies a relatively small amount of storage liquid in the second supply process (for example, an amount of storage liquid that is approximately 30% of the volume of the cap 60). This configuration allows the inside of the cap 60 to be efficiently cleaned with a small amount of storage liquid. On the other hand, if it is determined in S32 that the amount of ink ejected is large, that is, if an ejection process for a purge process is executed, the control unit 30 supplies a relatively large amount of storage liquid (for example, an amount of storage liquid that is approximately 90% of the volume of the cap 60) in the second supply process. With this configuration, the inside of the cap 60 can be properly cleaned.

[0065] In S38, the control unit 30 executes a second discharge process. In the second discharge process, the control unit 30 drives the third pump 78 to discharge the liquid in the cap 60 (i.e., the mixture of ink and storage liquid remaining in the cap 60) into the waste liquid tank 74 via the flow path 76. In S38, the cap 60 is located at the contact position, as in S36.

[0066] If ink remains in the cap 60 or in the flow path 76 between the cap 60 and the waste liquid tank 74, the solvent in the ink may evaporate, causing the solids contained in the ink to solidify. In this embodiment, as described above, the storage liquid supplied to the cap 60 contains a surfactant. The surfactant softens any solids that have formed through the action of its hydrophobic groups, and the surfactant can re-disperse the softened solids through the action of its hydrophilic groups. Therefore, by performing the second discharge process (S38), the solids in the re-dispersed ink can be discharged to the waste liquid tank 74 along with the storage liquid. This allows any solids that may have formed to be removed in an appropriate manner.

[0067] When a first transition condition is satisfied while the image recording device 10 is operating in the maintenance mode, the control unit 30 can transition the image recording device 10 to the storage mode and execute the storage process of FIG. 7. Here, the first transition condition is satisfied, for example, when an operation to turn off the power of the image recording device 10 is performed on the operation unit 22. For example, after executing the maintenance process of FIG. 8, the control unit 30 transitions the image recording device 10 from the maintenance mode to the storage mode and executes the storage process of FIG. 7. However, because the cap 60 is positioned in the contact position in S38 of FIG. 8, the process of S10 of FIG. 7 is omitted. Even in this case, the first supply process (S12) is executed with the cap 60 positioned in the contact position. By executing the storage process in this manner, it is possible to prevent the nozzles 38 from drying out and to prevent the ink in the nozzles 38 from being diluted.

[0068] In another embodiment, the cap 60 may be located at the separated position in S38 of Fig. 8. In this case, the control unit 30 may execute the storage process of Fig. 7 after executing the maintenance process of Fig. 8 without omitting the process of S10.

[0069] (Correspondence) The image recording device 10 is an example of a "liquid ejection device." The ink is an example of a "first liquid." The resin particles and colorant are an example of a "solid content." The sheet 2 is an example of a "medium." The storage liquid is an example of a "second liquid." The flow path 70 is an example of a "first flow path." The storage liquid tank 68 is an example of a "first tank." The flow path 76 is an example of a "second flow path." The waste liquid tank 74 is an example of a "second tank." The image recording mode is an example of a "first mode." The storage mode is an example of a "second mode."

[0070] Examples and Comparative Examples Next, the ink and storage solution will be specifically described with reference to examples and comparative examples, although the present invention is not limited to these examples in any way.

[0071] (Preparation of ink and storage solution) Three types of inks 1 to 3 with different densities were prepared by mixing the components shown in Table 1. Six types of storage solutions 1 to 6 with different densities were prepared by mixing the components shown in Table 2. The numerical values ​​in the columns showing each component in each table indicate the content of that component in that column relative to the total amount of ink and storage solution, respectively, and are expressed in weight percent.

[0072] [Table 1]

[0073] [Table 2]

[0074] Using each of the prepared inks and storage solutions, the degree of color mixing between the ink and storage solution and the re-dispersibility of solid matter in the storage solution were evaluated according to the methods described below.

[0075] (Color mixing test) Ink was introduced into the nozzle 38 of the image recording device 10, and the cap 60 was moved to the contact position. Storage liquid was then supplied into the cap 60. An amount of storage liquid sufficient to contact the nozzle surface 46 was supplied into the cap 60. After leaving the cap 60 for five minutes, the cap 60 was moved to the separated position, and the nozzle surface 46 was wiped with a sponge wiper (not shown). Then, ink was ejected from the nozzle 38 onto coated paper to create an evaluation sample. Furthermore, before the cap 60 was moved to the contact position (i.e., when the ink in the nozzle 38 was not in contact with the storage liquid), ink was ejected from the nozzle 38 onto coated paper to create a reference sample. The optical density (OD) values ​​of these samples were measured using a spectrophotometer (eXact, manufactured by X-Rite, light source: D50, viewing angle: 2°, ANSI-T) and the degree of color mixing between the ink and storage liquid was evaluated according to the following criteria. The evaluation results are shown in Table 3. A: The OD value of the evaluation sample is equal to the OD value of the reference sample. D: The OD value of the evaluation sample is lower than the OD value of the reference sample.

[0076] (Redispersion test) Ink and storage solution were mixed in a 1:9 ratio, and 12 μL of the mixture was dropped onto a polypropylene plate. The plate was then stored for 7 days at a temperature of 60°C and a humidity of 30%. 20 mL of pure water was then dropped onto the aggregated mixture, and the plate was manually shaken. The redispersibility of the solid matter in the storage solution was evaluated according to the following criteria. The evaluation results are shown in Table 3. A: No solid matter is present in the liquid when observed using an optical microscope (Nikon LV100ND) at 200x magnification. B: Visual observation revealed that 50% or more of the solid matter was dispersed in the liquid. C: Less than 50% of the solid matter was dispersed in the liquid by visual observation.

[0077] [Table 3]

[0078] (Color mixing evaluation results) When the OD value of the evaluation sample is equal to the OD value of the reference sample (evaluation result A), it can be said that the ink is not diluted by the storage liquid, i.e., the ink and the storage liquid are not mixed. On the other hand, when the OD value of the evaluation sample is lower than the OD value of the reference sample (evaluation result D), it can be said that the ink is diluted by the storage liquid, i.e., the ink and the storage liquid are mixed. As shown in Table 3, in Examples 1 to 6, where the density of the storage liquid was higher than that of the ink, it was confirmed that color mixing between the ink and the storage liquid could be suitably suppressed. In contrast, in Comparative Examples 1 to 3, where the density of the storage liquid was lower than that of the ink, the ink and the storage liquid mixed, resulting in color mixing. As such, it was found that when the density of the storage liquid is higher than that of the ink, mixing between the ink and the storage liquid can be suppressed even if the storage liquid supplied into the cap 60 comes into contact with the nozzle surface 46. Note that, as shown in Examples 1 to 6, when the density of the storage liquid is 0.002 (g / cm) higher than the density of the ink, 3 ) or more, it was found that color mixing could be suitably suppressed.

[0079] (Redispersibility evaluation results) As the solvent in the ink and storage liquid mixture evaporates, the solids (Hi-Loss-X QE-1042 and carbon black) solidify, generating solids. As shown in Table 3, Examples 1 to 3, which contain surfactants, particularly anionic surfactants, in the storage liquid, exhibited superior redispersibility of solids compared to Examples and Comparative Examples that do not contain surfactants. This is believed to be because the generated solids are softened by the action of the surfactant's hydrophobic groups, and the softened solids can be redispersed by the action of the surfactant's hydrophilic groups. Therefore, by performing the second discharge process (S38) in FIG. 9 in the image recording device 10, the solids in the redispersed ink can be discharged together with the storage liquid into the waste tank 74, allowing the solids to be removed appropriately. Generally, from the perspective of solid removal, the higher the compatibility between the ink and storage liquid, the better. For example, compatibility is improved when the ink and storage liquid contain common components, or when the content of the common components is similar. Therefore, by adjusting the compositions of the ink and the storage liquid so that the density of the storage liquid is greater than the density of the ink, it is possible to achieve both suppression of color mixing and removal of solid matter. Note that the term "common components" does not only refer to components with completely identical structures, but also includes, for example, components with the same basic skeleton.

[0080] In addition, Example 4, which contained a nonionic surfactant (Olfine E1010) in the storage solution, showed lower redispersibility than Example 3, which contained an anionic surfactant (Sunol NL-1430) in the storage solution. This is thought to be because the negative charge of the anionic surfactant acts favorably on solid matter, promoting the softening of the solid matter. Also, when the surfactant contained in the storage solution is an anionic surfactant, the effect of the surfactant's hydrophilic group is thought to be improved.

[0081] Furthermore, Examples 1 and 2 and Comparative Example 2, in which the storage solution contained a water-soluble polymer, showed superior redispersibility compared to Examples and Comparative Examples in which the storage solution did not contain a water-soluble polymer. This is thought to be because the inclusion of a water-soluble polymer in the storage solution effectively utilizes the action of the hydrophilic group of the surfactant. As a result, even if the ink and storage solution are difficult to mix due to the difference in density between the two, the storage solution can effectively remove solid matter.

[0082] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above embodiments are listed below.

[0083] (Variation 1) In the above-described embodiment, instead of ink, clear ink that does not contain coloring material may be ejected from the nozzles 38 of the head 32 toward the sheet 2. The clear ink is used to impart gloss, protect the printed image, and improve the print quality. The clear ink is a water-based ink that contains resin particles as solid content. In this modification, the clear ink and the resin particles are examples of the "first liquid" and the "solid content," respectively.

[0084] (Variation 2) In the above-described embodiment, instead of ink, a pretreatment liquid that does not contain a coloring material may be ejected from the nozzles 38 of the head 32 toward the sheet 2. The pretreatment liquid is a liquid that is ejected onto the sheet 2 prior to the ink before printing, and is used to improve print image quality, such as the color development of the ink. The pretreatment liquid contains resin particles as solid content. In this modification, the pretreatment liquid and the resin particles are examples of the "first liquid" and the "solid content," respectively. Note that, from the viewpoint of the cleaning effect of the cap 60 with the storage liquid, for example, when the solid content or additives contained in the pretreatment liquid are cationic, the storage liquid preferably contains a cationic surfactant or a nonionic surfactant.

[0085] (Variation 3) 7, the order of S10 and S12 may be reversed. That is, the control unit 30 may move the cap 60 from the separated position to the contact position after executing the first supply process. In other words, the first supply process may be executed with the cap 60 positioned at the contact position, or may be executed with the cap 60 positioned at the separated position. Generally speaking, as in the above embodiment, the first supply process may be executed after the process of moving the cap 60 from the separated position to the contact position, or as in this modified example, the first supply process may be executed before the process of moving the cap 60 from the separated position to the contact position.

[0086] (Variation 4) 7, the order of S20 and S22 may be reversed. That is, the control unit 30 may execute the first ejection process after moving the cap 60 from the contact position to the separation position. Generally speaking, as in the above embodiment, the process of moving the cap 60 from the contact position to the separation position may be executed after the first ejection process, or as in this modified example, the process of moving the cap 60 from the contact position to the separation position may be executed before the first ejection process.

[0087] (Variation 5) The "first transition condition" is not limited to the above embodiment, and may be, for example, the arrival of a predetermined time, or the user inputting an instruction to execute a storage process via the operation unit 22. Furthermore, the "second transition condition" is not limited to the above embodiment, and may be, for example, the arrival of a predetermined time.

[0088] (Variation 6) S14 and S16 in Fig. 7 can be omitted. In this modification, the "replenishment process" can be omitted.

[0089] (Variation 7) The process of FIG. 8 can be omitted. In this modified example, the "ejection process," "second supply process," "second discharge process," and "third discharge process" can be omitted. Alternatively, only S34 of the processes of FIG. 8 may be omitted. In this modified example, the "third discharge process" can be omitted. In this case, in the second discharge process (S36), a mixture of the ink discharged into the cap 60 and the storage liquid supplied into the cap 60 is discharged to the waste liquid tank 74 via the flow path 76.

[0090] (Variation 8) 8 may be executed repeatedly. For example, if it is determined in S32 that the amount of ink ejected is small, S36 and S38 may be executed M times (M is an integer greater than or equal to 1), and if it is determined in S32 that the amount of ink ejected is large, S36 and S38 may be executed N times (N is an integer greater than M). In this case, the same amount of storage liquid (e.g., approximately 30% of the volume of the cap 60) may be supplied in the supply process of S36 regardless of the determination result in S32. With this configuration, the inside of the cap 60 can be appropriately cleaned according to the amount of ink ejected in S30 without changing the amount of storage liquid supplied per time.

[0091] (Variation 9) 8 can be omitted. That is, in the supply process of S36, the same amount of storage liquid may be supplied regardless of the amount of ink ejected in the ejection process of S30. Generally speaking, the "control unit" does not need to determine the amount of second liquid to be supplied in the second supply process based on the amount of first liquid ejected in the ejection process.

[0092] (Variation 10) The ink is not limited to the above embodiment and may not contain resin particles, and the storage liquid is not limited to the above embodiment and may not contain a surfactant or a water-soluble polymer, for example.

[0093] Furthermore, the technical elements described in this specification or drawings may exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings may achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

[0094] In the scope of the claims at the time of filing, even if each claim depends on only some of the claims, it is not limited to the fact that each claim can depend on only those some of the claims. To the extent that there is no technical contradiction, each claim can also depend on other claims that were not dependent at the time of filing. In other words, the technology of each claim can be combined in various ways as follows: (Item 1) A liquid ejection device, a head for ejecting a first liquid containing solid content from a nozzle toward a medium; a cap that is movable between a contact position in which the cap contacts the head to cover the nozzle and a spaced position in which the cap is spaced from the head; a first tank that stores a second liquid different from the first liquid and is connected to the cap via a first flow path; a second tank connected to the cap via a second flow path different from the first flow path; A control unit; Equipped with the density of the second liquid is greater than the density of the first liquid; The control unit a first supply process of supplying the second liquid from the first tank into the cap via the first flow path; a first discharge process of discharging the second liquid from inside the cap to the second tank via the second flow path. (Item 2) the liquid ejection device is operable in any one of a plurality of modes including a first mode for ejecting the first liquid toward the medium and a second mode for not ejecting the first liquid toward the medium; The control unit When a first transition condition for the liquid ejection device to transition to the second mode is satisfied, the supply process is performed with the cap located at the contact position; Item 1. A liquid ejection device according to item 1, wherein when a second transition condition for the liquid ejection device to transition from the second mode to the first mode is satisfied, the first ejection process is executed and the cap is moved from the contact position to the separated position. (Item 3) Item 3. A liquid ejection device according to item 2, wherein the first transition condition is satisfied when the time during which the first liquid is not ejected from the head exceeds a predetermined time, or when an operation is performed to turn off the power of the liquid ejection device. (Item 4) 4. A liquid ejection device according to item 2 or 3, wherein the second transition condition is satisfied when an operation is performed to transition the liquid ejection device to the first mode, or when an operation is performed to turn on the power of the liquid ejection device. (Item 5) The liquid ejection device described in any one of items 1 to 4, wherein the control unit further executes a refilling process to refill the second liquid from the first tank into the cap via the first flow path at a predetermined timing after the first supply process is executed. (Item 6) Item 6. The liquid ejection device according to item 5, wherein the predetermined timing is a timing when a predetermined time has elapsed since the first supply process was executed. (Item 7) The control unit further a discharge process of discharging the first liquid from the nozzle into the cap; a second supply process of supplying the second liquid from the first tank into the cap through the first flow path while the cap is in the contact position after the ejection process has been performed; A liquid ejection device described in any one of items 1 to 6, which is capable of performing a second discharge process to discharge liquid in the cap to the second tank via the second flow path after the second supply process has been performed. (Item 8) The liquid ejection device described in item 7, wherein the control unit is further capable of performing a third ejection process to eject the first liquid from the cap after the ejection process has been performed and before the second supply process. (Item 9) Item 9. The liquid ejection device according to item 7 or 8, wherein the control unit determines the supply amount of the second liquid in the second supply process based on the ejection amount of the first liquid in the ejection process. (Item 10) 10. The liquid ejection device according to any one of items 1 to 9, wherein the second liquid contains a surfactant and water. (Item 11) Item 11. The liquid ejection device according to item 10, wherein the surfactant includes an anionic surfactant. (Item 12) Item 12. The liquid ejection device according to any one of items 1 to 11, wherein the second liquid further comprises a water-soluble polymer. (Item 13) Item 13. The liquid ejection device according to any one of items 1 to 12, wherein the solid content includes resin particles. (Item 14) A liquid set used in the liquid ejection device according to item 1, the first liquid containing the solid content; the second liquid having a density greater than the density of the first liquid; A liquid set comprising: [Explanation of symbols]

[0095] 10: Image recording device, 12: Housing, 22: Operation unit, 30: Control unit, 32: Head, 34: Frame, 36: Discharge module, 38: Nozzle, 46: Nozzle surface, 48: Ink tank, 58: Support base, 60: Cap, 62: Bottom surface, 64: Side surface, 66: Lip, 68: Storage liquid tank, 74: Waste liquid tank, 80: Internal space

Claims

1. A liquid ejection device, a head for ejecting a first liquid containing solid content from a nozzle toward a medium; a cap that is movable between a contact position in which the cap contacts the head to cover the nozzle and a spaced position in which the cap is spaced from the head; a first tank that stores a second liquid different from the first liquid and is connected to the cap via a first flow path; a second tank connected to the cap via a second flow path different from the first flow path; A control unit; Equipped with the density of the second liquid is greater than the density of the first liquid; The control unit a first supply process of supplying the second liquid from the first tank into the cap through the first flow path; a first discharge process of discharging the second liquid from inside the cap to the second tank via the second flow path.

2. the liquid ejection device is operable in any one of a plurality of modes including a first mode for ejecting the first liquid toward the medium and a second mode for not ejecting the first liquid toward the medium; The control unit When a first transition condition for the liquid ejection device to transition to the second mode is satisfied, the first supply process is executed with the cap located at the contact position; 2. The liquid ejection device according to claim 1, wherein when a second transition condition for the liquid ejection device to transition from the second mode to the first mode is satisfied, the first ejection process is executed and the cap is moved from the contact position to the separated position.

3. 3. The liquid ejection device according to claim 2, wherein the first transition condition is satisfied when the time during which the first liquid is not ejected from the head exceeds a predetermined time, or when an operation is performed to turn off the power supply of the liquid ejection device.

4. 3. The liquid ejection device according to claim 2, wherein the second transition condition is satisfied when an operation is performed to transition the liquid ejection device to the first mode and when an operation is performed to turn on the power of the liquid ejection device.

5. The liquid ejection device according to claim 1, wherein the control unit further executes a refilling process to refill the second liquid from the first tank into the cap via the first flow path at a predetermined timing after the first supply process is executed.

6. The liquid ejection apparatus according to claim 5 , wherein the predetermined timing is a timing when a predetermined time has elapsed since the first supply process was executed.

7. The control unit further a discharge process of discharging the first liquid from the nozzle into the cap; a second supply process of supplying the second liquid from the first tank into the cap through the first flow path while the cap is positioned at the contact position after the ejection process has been performed; The liquid ejection device according to claim 1 , further comprising: a second discharge process for discharging the liquid in the cap to the second tank via the second flow path after the second supply process has been performed.

8. The liquid ejection device according to claim 7, wherein the control unit is further capable of performing a third ejection process to eject the first liquid from inside the cap to the second tank via the second flow path after the ejection process has been performed and before the second supply process.

9. The liquid ejection apparatus according to claim 7 , wherein the control unit determines the supply amount of the second liquid in the second supply process based on the ejection amount of the first liquid in the ejection process.

10. The liquid ejection device according to claim 1 , wherein the second liquid contains a surfactant and water.

11. The liquid ejection device according to claim 10 , wherein the surfactant includes an anionic surfactant.

12. The liquid ejection device of claim 11 , wherein the second liquid further includes a water-soluble polymer.

13. The liquid ejection device according to claim 1 , wherein the solid content includes resin particles.

14. A liquid set for use in the liquid ejection device according to claim 1, the first liquid containing the solid content; the second liquid having a density greater than the density of the first liquid; A liquid set comprising:

Images