Cleaning solution, cleaning solution and ink set, and inkjet system

Abstract

To provide a cleaning fluid having corrosion prevention ability for an ink discharge head and peripheral members and ink-removing ability.SOLUTION: A cleaning fluid comprises water, and an organic solvent containing a compound having two or more carbon atoms and two or three OH groups. The cleaning fluid has a pH of 7 or more and 10 or less, a phosphate ion concentration of 100 ppm or more and 5,000 ppm or less, a percentage of the organic solvent of 5 mass% or more and 20 mass% or less to the total amount of the cleaning fluid, and a percentage of the compound having two or three OH groups of 60 mass% or more and 100 mass% or less to the total amount of the organic solvent.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a cleaning liquid, a set of a cleaning liquid and ink, and an inkjet system.

Background Art

[0002] Conventionally, as ink for inkjet, dye ink has been the mainstream in terms of good color development and high reliability, etc. In recent years, pigment ink has also been increasingly used. As a method of firmly and finely drawing a pattern with a dye on a fabric, screen printing, roller printing, rotary screen printing, gravure printing or a transfer printing method using these printing techniques is known. In recent years, a method of directly printing (dyeing) on a fiber material such as a fabric (electrophotographic method or inkjet method) using a signal of an image read by a scanner and processed by a computer for an image such as a pattern to be dyed, or a method of once printing an image etc. on a transfer paper and transferring the image etc. to a fiber material such as a fabric has been put into practical use.

[0003] When using ink for printing on a fiber material such as a fabric as described above, various color materials and solvents are used. In particular, the chemical structure of the dye compound contains a reactive group, and there is a concern that members in contact with the head and the ink and their peripheral members may be corroded due to deterioration of the ink itself etc.

[0004] Patent Document 1 proposes that it is possible to prevent corrosion by setting the phosphate ion concentration in the aqueous inkjet recording ink containing a colorant, water and a water-soluble organic solvent to 35 ppm or less. Patent Document 2 proposes a method for protecting the surface of a metal in contact with ink, and it is possible to reduce the corrosion of the metal surface by using an ink containing a phosphate in a concentration range of 0.01 mass% to 1.0 mass% and a citrate in a concentration range of 0.001 mass% to 1.0 mass%.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, if inkjet ink remains in the inkjet head for a long period of time, the dyes and pigments may deteriorate, and this can easily lead to corrosion of the wetted parts, including the head, especially if the ink has a low pH or high electrical conductivity. When the ink has a low pH and high conductivity, the deterioration reaction is accelerated, making corrosion more likely. When corrosion occurs, it can lead to changes in the shape of the nozzle holes, resulting in reduced ejection stability, ink clogging, and abnormalities in the direction of ink ejection. Furthermore, if the corrosion progresses further, ink leaks may occur, where ink leaks out from parts that come into contact with the ink, such as the head and the liquid delivery system.

[0006] The present invention aims to provide a cleaning solution that offers excellent ink removal capabilities, prevents corrosion of ink ejection heads and surrounding components, and maintains stable ejection characteristics over a long period of time. [Means for solving the problem]

[0007] The present invention, which solves the above problems, relates to a cleaning solution having the configuration described below. A cleaning solution comprising water and an organic solvent containing a compound having two or more carbon atoms and two or three OH groups, The pH is between 7 and 10. The phosphate ion concentration is between 100 ppm and 5000 ppm. The proportion of the organic solvent in the total amount of the cleaning solution is 5% by mass or more and 20% by mass or less. The proportion of the compound having two or three OH groups in the total amount of the organic solvent is 60% by mass or more and 100% by mass or less. A cleaning solution characterized by the following features. [Effects of the Invention]

[0008] The cleaning solution of the present invention offers excellent ink removal properties, prevents corrosion of the ink ejection head and surrounding components, and maintains stable ejection characteristics over a long period of time. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall schematic diagram relating to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing an example of a main tank in one embodiment of the present invention. [Modes for carrying out the invention]

[0010] (Cleaning solution) The cleaning solution of the present invention is a cleaning solution used for cleaning ink, and contains at least water and an organic solvent. The aforementioned organic solvent contains a compound having two or more carbon atoms and two or three OH groups. Furthermore, the cleaning solution of the present invention has a pH of 7 or more and 10 or less, and a phosphate ion concentration of 100 ppm or more and 5000 ppm or less. Furthermore, the proportion of the organic solvent in the total amount of the cleaning solution is 5% by mass or more and 20% by mass or less, and the proportion of the compound having 2 or 3 OH groups in the total amount of the organic solvent is 60% by mass or more and 100% by mass or less.

[0011] The cleaning solution of the present invention preferably contains a surfactant, and may further contain other components as needed.

[0012] —Organic Solvents— The compounds used as components of the organic solvent in the cleaning solution, which have two or more carbon atoms and two or three OH groups, are at least one selected from the group consisting of propylene glycol, glycerin, 1,2-ethanediol, and dipropylene glycol. Furthermore, other organic solvents are preferably compounds with an amide group-containing ring structure, and such compounds are preferably 2-pyrrolidone and / or ε-caprolactam. The proportion of the organic solvent in the total amount of the cleaning solution is 5% by mass or more and 20% by mass or less. In addition, the proportion of the compound having two or three OH groups in the total amount of the organic solvent is 60% by mass or more and 100% by mass or less. As the organic solvent, the same solvents as those described as components of the ink described later can be used.

[0013] —Water— There are no particular restrictions on the water used in the cleaning liquid, and it can be appropriately selected according to the purpose. Examples include pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. The content in the cleaning liquid is preferably 10% by mass or more and 98% by mass or less, and more preferably 80% by mass or more and 95% by mass or less.

[0014] —Resin— The cleaning liquid may or may not contain resin, but it is desirable not to contain resin. When the cleaning liquid contains resin, it is preferably the same type and content as the resin contained in the ink described later.

[0015] —Additive— The cleaning liquid of the present invention may contain a surfactant, an antiseptic and antifungal agent, a rust inhibitor, a pH adjuster, etc. as necessary.

[0016] (Surfactant) There are no particular restrictions on the surfactant, and it can be appropriately selected according to the purpose. Examples include silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, anionic surfactants, etc. These may be used alone or in combination of two or more.

[0017] There are no particular restrictions on the silicone-based surfactant, and it can be appropriately selected according to the purpose, but those that do not decompose even at high pH are preferred. Examples include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, side-chain and both-end modified polydimethylsiloxane, etc. The side-chain modified polydimethylsiloxane, for example, is formed by introducing a modifying group into the Si side chain of a polydimethylsiloxane represented by the general formula (S-1). The aforementioned end-modified polydimethylsiloxane indicates, for example, the introduction of modifying groups at both ends of a polydimethylsiloxane represented by the general formula (S-1). The aforementioned one-ended modified polydimethylsiloxane indicates, for example, the introduction of a modifying group to one end of a polydimethylsiloxane represented by the general formula (S-1). The aforementioned side-chain end-modified polydimethylsiloxane indicates, for example, the introduction of modifying groups to the Si portion of the polydimethylsiloxane represented by the general formula (S-1) and to both ends. [ka] (However, in general formula (S-1), m and n each represent an integer independently, and X represents a side chain.) For example, the side-chain modified polydimethylsiloxane can be made into a polyether-modified silicone surfactant by introducing a polyalkylene oxide structure represented by general formula (S-2) to the Si side chain X of dimethylpolysiloxane represented by general formula (S-1). [ka] (However, in general formula (S-2), a and b each represent independent integers, R represents an alkylene group, and R' represents an alkyl group.)

[0018] The aforementioned modifying group is not particularly limited and can be appropriately selected depending on the purpose. Examples include a polyoxyethylene group, a polyoxyethylene polyoxypropylene group, and a polyalkylene oxide structure.

[0019] As the aforementioned silicone-based surfactant, a suitably synthesized one may be used, or a commercially available product may be used. Commercially available silicone-based surfactants include, for example, those from BIC Chemie Inc., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd. As the polyether-modified silicone surfactant, commercially available products can be used, such as KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), DOWSIL FZ-2105, DOWSIL FZ-2154, DOWSIL FZ-2161, DOWSIL FZ-2162, and DOWSIL FZ-2164 (Toray Dow Corning Silicone Co., Ltd.).

[0020] The fluorine-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains. Among these, polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains are preferred because they have low foaming properties. The fluorine-based surfactant is more preferably a compound represented by general formula (F-1) and general formula (F-2). [ka] (However, in general formula (F-1), m and n each represent an integer independently.) In the compound represented by the above general formula (F-1), m is preferably an integer between 0 and 10, and n is preferably an integer between 0 and 40, in order to impart water solubility. General formula (F-2) C n F 2n+1- CH2CH(OH)CH2-O-(CH2CH2O) a -Y (However, in the above general formula (F-2), Y is H or C m F 2m+1m is an integer from 1 to 6, or CH2CH(OH)CH2-CmF 2m+1 m is an integer between 4 and 6, or CpH 2p+1 (where p is an integer between 1 and 19, n is an integer between 1 and 6, and a is an integer between 4 and 14.)

[0021] Specific examples of the perfluoroalkyl sulfonic acid compounds include, for example, perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate salts.

[0022] Specific examples of the perfluoroalkylcarboxylic acid compounds include, for example, perfluoroalkylcarboxylic acids and perfluoroalkylcarboxylic acid salts.

[0023] Specific examples of polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains include, for example, sulfate ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains, and salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains.

[0024] Examples of counterions for the salts in the aforementioned fluorine-based surfactants include Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, and NH(CH2CH2OH)3.

[0025] There are no particular restrictions on the fluorinated surfactant, and it can be appropriately selected depending on the purpose, but compounds with 2 to 16 carbon atoms substituted with fluorine are preferred, and compounds with 4 to 16 carbon atoms substituted with fluorine are more preferred.

[0026] A commercially available product may be used as the aforementioned fluorine-based surfactant. Examples of commercially available fluorine-based surfactants include Surflon S-111, Surflon S-112, Surflon S-113, Surflon S-121, Surflon S-131, Surflon S-132, Surflon S-141, Surflon S-145 (all manufactured by AGC Seimi Chemical Co., Ltd.), Flurad FC-93, Flurad FC-95, Flurad FC-98, Flurad FC-129, Flurad FC-135, Flurad FC-170C, Flurad FC-430, Flurad FC-431 (all manufactured by 3M Japan Limited), Megafac F-470, Megafac F-1405, Megafac F-474 (all manufactured by DIC Corporation), Zonyl TBS, Zonyl FSP, Zonyl FSA, Zonyl (Zo Examples include nyl)FSN-100, Zonyl FSN, Zonyl FSO-100, Zonyl FSO, Zonyl FS-300, Zonyl UR, Capstone FS-30, Capstone FS-31, Capstone FS-3100, Capstone FS-34, Capstone FS-35 (all manufactured by Chemors), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Corporation), Polyfox PF-136A, Polyfox PF-156A, Polyfox PF-151N, Polyfox PF-154, Polyfox PF-159 (manufactured by Omnova), and Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.). Among these, Zonil FS-300, Zonil FS-3100, Capstone FS-34 (all manufactured by Chemors), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Corporation), Polyfox PF-151N (manufactured by Omnova), and Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) are preferred because they offer excellent print quality, particularly significantly improved color development, penetration into paper, wettability, and uniform dyeing.

[0027] The aforementioned amphoteric surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine.

[0028] The nonionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohols.

[0029] The anionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, and polyoxyethylene alkyl ether sulfate salts.

[0030] There are no particular restrictions on the content of the surfactant in the ink, but it is preferably 0.001% by mass or more and 5% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, from the standpoint of excellent wettability, ejection stability, and improved image quality.

[0031] The surfactant can be used as an antifoaming agent. There are no particular restrictions on the defoaming agent, and it can be appropriately selected depending on the purpose. Examples include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents. Among these, silicone-based defoaming agents are preferred because they have excellent foam-breaking effects. These may be used individually or in combination of two or more types.

[0032] (preservative and fungicide) There are no particular restrictions on the preservatives and fungicides used; for example, 1,2-benzisothiazolin-3-one can be used.

[0033] (Rust inhibitor) As a rust inhibitor, there are no particular restrictions as long as it exhibits rust-preventive properties; for example, heterocyclic aromatic compounds can be used. The heterocyclic aromatic compound exhibits rust prevention properties on the metal parts inside the nozzle by bonding with metal ions to form an insoluble film.

[0034] The aforementioned heterocyclic aromatic compound is not particularly limited and can be appropriately selected depending on the purpose, but examples include benzotriazole compounds.

[0035] The benzotriazole compound is not particularly limited and can be appropriately selected depending on the purpose. Examples include benzotriazole, carboxybenzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)benzotriazole, and 2-(2-hydroxy-5-t-octylphenyl)benzotriazole.

[0036] There are no particular restrictions on the content of the benzotriazole compound in the ink, but it is preferably 0.001% by mass or more and 1.0% by mass or less, and more preferably 0.005% by mass or more and 0.5% by mass or less.

[0037] (Phosphate compounds) There are no particular restrictions on the phosphate compounds contained in the cleaning solution, and they can be appropriately selected depending on the purpose. Examples include sodium hydrogen phosphate, lithium phosphate, sodium phosphate, potassium phosphate, and ammonium phosphate. The concentration of phosphate ions in the washing solution is preferably between 100 ppm and 5000 ppm.

[0038] (pH adjuster) As a pH adjusting agent, there are no particular restrictions as long as it can adjust the pH to between 7 and 10, and examples include amines such as diethanolamine and triethanolamine. Furthermore, a pH buffering agent may be included to stabilize the pH. There are no particular restrictions on the pH buffering agent, and examples include phosphate compounds and N-cyclohexyl-2-aminoethanesulfonic acids.

[0039] The physical properties of the cleaning solution of the present invention are not particularly limited and can be appropriately selected depending on the purpose, but for example, viscosity, surface tension, pH, etc. are preferably within the following ranges.

[0040] While there are no particular limitations on the surface tension of the cleaning solution of the present invention at 25°C, it is preferably 35 mN / m or less, and more preferably 32 mN / m or less, from the viewpoint that the ink is adequately leveled on the recording medium and the ink drying time is shortened.

[0041] (ink) The ink in the present invention comprises water, an organic solvent, and a colorant. Dyes or pigments can be used as colorants.

[0042] -dye- The dyes included in the ink are not particularly limited and can include reactive dyes, acid dyes, direct dyes, and basic dyes. They may be used individually or in combination of two or more. The present invention is often highly effective when the colorant is a dye, and is particularly effective when it is a reactive dye. There are no particular restrictions on suitable dyes as long as they are reactive dyes, and they can be appropriately selected according to the purpose. When the dye ink has a vinyl sulfone group, keeping the pH of the ink low improves the stability of the ink, and since this is particularly prone to corrosion, the cleaning solution, ink set, and inkjet system of the present invention are highly effective.Specific examples of reactive dyes include, for example, CI Reactive Black 1, CI Reactive Black 3, CI Reactive Black 5, CI Reactive Black 8, CI Reactive Black 10, CI Reactive Black 12, CI Reactive Black 13, CI Reactive Black 39, CI Reactive Blue 2, CI Reactive Blue 3, CI Reactive Blue 5, CI Reactive Blue 7, CI Reactive Blue 13, CI Reactive Blue 14, CI Reactive Blue 15, CI Reactive Blue 25, CI Reactive Blue 26, CI Reactive Blue 39, CI Reactive Blue 40, CI Reactive Blue 49, CI Reactive Red 3, CI Reactive Red 4, CI Reactive Red 7, CI Reactive Red 15, CI Reactive Red 16, CI Reactive Red 24, CI Reactive Red Examples include CI Reactive Red 29, CI Reactive Red 31, CI Reactive Red 32, CI Reactive Red 33, CI Reactive Red 43, CI Reactive Red 45, CI Reactive Red 46, CI Reactive Red 58, CI Reactive Red 59, CI Reactive Red 256, CI Reactive Red 245, CI Reactive Yellow 3, CI Reactive Yellow 6, CI Reactive Yellow 12, CI Reactive Yellow 18, CI Reactive Yellow 95, CI Reactive Yellow 99, CI Reactive Orange 2, CI Reactive Orange 5, CI Reactive Orange 9, CI Reactive Orange 12, CI Reactive Orange 13, CI Reactive Orange 39, CI Reactive Green 5, CI Reactive Green 8, CI Reactive Violet 1, and CI Reactive Violet 2. These may be used individually or in combination of two or more types.

[0043] Examples of the aforementioned acid dyes include CI Acid Yellow 17, CI Acid Yellow 23, CI Acid Yellow 42, CI Acid Yellow 44, CI Acid Yellow 79, CI Acid Yellow 142, CI Acid Red 1, CI Acid Red 8, CI Acid Red 13, CI Acid Red 14, CI Acid Red 18, CI Acid Red 26, CI Acid Red 27, CI Acid Red 35, CI Acid Red 37, CI Acid Red 42, CI Acid Red 52, CI Acid Red 82, CI Acid Red 87, CI Acid Red 89, CI Acid Red 92, Examples include CI Acid Red 97, CI Acid Red 106, CI Acid Red 111, CI Acid Red 114, CI Acid Red 115, CI Acid Red 134, CI Acid Red 186, CI Acid Red 249, CI Acid Red 254, CI Acid Red 289, CI Acid Blue 9, CI Acid Blue 29, CI Acid Blue 45, CI Acid Blue 92, CI Acid Blue 249, CI Acid Black 1, CI Acid Black 2, CI Acid Black 7, CI Acid Black 24, CI Acid Black 26, and CI Acid Black 94. Examples of the aforementioned food dyes include CI Food Yellow 3, CI Food Red 14, CI Food Black 1, and CI Food Black 2.

[0044] Examples of the direct dyes mentioned above include CI Direct Yellow 1, CI Direct Yellow 12, CI Direct Yellow 24, CI Direct Yellow 26, CI Direct Yellow 33, CI Direct Yellow 44, CI Direct Yellow 50, CI Direct Yellow 86, CI Direct Yellow 120, CI Direct Yellow 132, CI Direct Yellow 142, CI Direct Yellow 144, CI Direct Red 1, CI Direct Red 4, CI Direct Red 9, CI Direct Red 13, CI Direct Red 17, CI Direct Red 20, CI Direct Red 28, CI Direct Red 31, CI Direct Red 39, CI Direct Red 80, CI Direct Red 81, CI Direct Red 83, CI Direct Red 89, CI Direct Red 225, CI Direct Red 227, CI Direct Orange 26, CI Direct Orange 29, CI Direct Orange 62, CI Direct Orange 102, CI Direct Blue 1, CI Direct Blue 2, CI Direct Blue 6, CI Direct Blue 15, CI Direct Blue 22, CI Direct Blue 25, CI Direct Blue 71, CI Direct Blue 76, CI Direct Blue 79, CI Direct Blue 86, CI Direct Blue 87, CI Direct Blue 90, CI Direct Blue 98, CI Direct Blue 163, CI Direct Blue 165, CI Direct Blue 199, CI Direct Blue 202, CI Direct Black 19, CI Direct Black 22, CI Direct Black 32, CI Direct Black 38, CI Direct Black 51, CI Direct Black 56, CI Direct Black 71, CI Direct Black 74, CI Direct Black 75, CI Direct Black 77, CI Direct Black 154, CIExamples include Direct Black 168 and CI Direct Black 171.

[0045] Examples of the basic dyes include CI Basic Yellow 1, CI Basic Yellow 2, CI Basic Yellow 11, CI Basic Yellow 13, CI Basic Yellow 14, CI Basic Yellow 15, CI Basic Yellow 19, CI Basic Yellow 21, CI Basic Yellow 23, CI Basic Yellow 24, CI Basic Yellow 25, CI Basic Yellow 28, CI Basic Yellow 29, CI Basic Yellow 32, CI Basic Yellow 36, CI Basic Yellow 40, CI Basic Yellow 41, CI Basic Yellow 45, CI Basic Yellow 49, CI Basic Yellow 51, CI Basic Yellow 53, CI Basic Yellow 63, CI Basic Yellow 64, CI Basic Yellow 65, CI Basic Yellow 67, CI Basic Yellow 70, CI Basic Yellow 73, CI Basic Yellow 77, CI Basic Yellow 87, CI Basic Yellow 91, CI Basic Red 2, CI Basic Red 12, CI Basic Red 13, CI Basic Red 14, CI Basic Red 15, CI Basic Red 18, CI Basic Red 22, CI Basic Red 23, CI Basic Red 24, CI Basic Red 27, CI Basic Red 29, CI Basic Red 35, CI Basic Red 36, CI Basic Red 38, CI Basic Red 39, CI Basic Red 46, CI Basic Red 49, CI Basic Red 51, CI Basic Red 52, CI Basic Red 54, CI Basic Red 59, CI Basic Red 68, CI Basic Red 69, CI Basic Red 70, CI Basic Red 73, CI Basic Red 78, CI Basic Red 82, CI Basic Red 102, CI Basic Red 104, CIBasic Red 109, CI Basic Red 112, CI Basic Blue 1, CI Basic Blue 3, CI Basic Blue 5, CI Basic Blue 7, CI Basic Blue 9, CI Basic Blue 21, CI Basic Blue 22, CI Basic Blue 26, CI Basic Blue 35, CI Basic Blue 41, CI Basic Blue 45, CI Basic Blue 47, CI Basic Blue 54, CI Basic Blue 62, CI Basic Blue 65, CI Basic Blue 66, CI Basic Blue 67, CI Basic Blue Examples include 69, CI Basic Blue 75, CI Basic Blue 77, CI Basic Blue 78, CI Basic Blue 89, CI Basic Blue 92, CI Basic Blue 93, CI Basic Blue 105, CI Basic Blue 117, CI Basic Blue 120, CI Basic Blue 122, CI Basic Blue 124, CI Basic Blue 129, CI Basic Blue 137, CI Basic Blue 141, CI Basic Blue 147, CI Basic Blue 155, CI Basic Black 2, and CI Basic Black 8.

[0046] Other reactive dyes include, for example, CI Reactive Black 4, CI Reactive Black 7, CI Reactive Black 11, CI Reactive Black 17, CI Reactive Yellow 1, CI Reactive Yellow 5, CI Reactive Yellow 11, CI Reactive Yellow 13, CI Reactive Yellow 14, CI Reactive Yellow 20, CI Reactive Yellow 21, CI Reactive Yellow 22, CI Reactive Yellow 25, CI Reactive Yellow 40, CI Reactive Yellow 47, CI Reactive Yellow 51, CI Reactive Yellow 55, CI Reactive Yellow 65, CI Reactive Yellow 67, and CI Reactive Yellow Examples include CI Reactive Red 1, CI Reactive Red 14, CI Reactive Red 17, CI Reactive Red 25, CI Reactive Red 26, CI Reactive Red 37, CI Reactive Red 44, CI Reactive Red 55, CI Reactive Red 60, CI Reactive Red 66, CI Reactive Red 74, CI Reactive Red 79, CI Reactive Red 96, CI Reactive Red 97, CI Reactive Blue 23, CI Reactive Blue 32, CI Reactive Blue 35, CI Reactive Blue 38, CI Reactive Blue 41, CI Reactive Blue 63, CI Reactive Blue 80, and CI Reactive Blue 95.

[0047] There are no particular restrictions on the content of the dye in the ink, but from the viewpoint of improving image density, good fixability and ejection stability, it is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less.

[0048] —Pigments— Pigments can also be used as colorants in ink. Inorganic or organic pigments can be used. These may be used individually or in combination of two or more. Mixed crystals may also be used as pigments. Examples of pigments that can be used include black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, and glossy or metallic pigments such as gold and silver. As inorganic pigments, titanium dioxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chromium yellow can be used, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method. In addition, organic pigments such as azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, and aniline black can be used. Of these pigments, those with good affinity to the solvent are preferably used. Other uses such as resin hollow particles and inorganic hollow particles are also possible. Specific examples of pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or metals such as copper, iron (CI Pigment Black 11), and titanium dioxide, as well as organic pigments such as aniline black (CI Pigment Black 1). Furthermore, for color applications, we have CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, and CI Pigment Ole. Orange 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 ( (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Examples include Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; and CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36.

[0049] There are no particular restrictions on the content of the pigment in the ink, but from the viewpoint of improving image density, good fixation and ejection stability, it is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less.

[0050] -water- There are no particular restrictions on the type of water used; it can be selected appropriately depending on the purpose. Examples include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water. The amount of water contained in the ink is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of ink drying properties and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.

[0051] —Organic Solvents— The organic solvents used as components of the ink are not particularly limited as long as they are water-soluble organic solvents and can be appropriately selected according to the purpose. Examples include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds. These can be used individually or in combination of two or more types.

[0052] Specific examples of the aforementioned water-soluble organic solvents include, for example, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, and 2,4-pentanediol. Polyhydric alcohols such as ol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, etc., ethylene glycol monoethyl ether, ethylene glycol monobutyl Examples include polyhydric alcohol alkyl ethers such as ethers, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; propylene carbonate; and ethylene carbonate.

[0053] As the aforementioned water-soluble organic solvents, polyol compounds having 8 or more carbon atoms and glycol ether compounds are suitably used when paper is used as the recording medium, and can improve the penetration of ink into the paper. Specific examples of the polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. Specific examples of the glycol ether compounds include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether, as well as polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0054] There are no particular restrictions on the boiling point of the organic solvent, but it is preferable that it be 250°C or lower in terms of wetting effect and good drying properties.

[0055] The content of the organic solvent in the ink is not particularly limited, but from the viewpoint of ink drying properties and ejection reliability, it is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.

[0056] -resin- There are no particular restrictions on the type of resin contained in the ink, and it can be appropriately selected according to the purpose. Examples include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Resin particles made from these resins may also be used. These can be used individually or in combination of two or more types. The aforementioned resin particles, in the form of a resin emulsion dispersed with water as a dispersion medium, can be mixed with materials such as colorants and organic solvents to obtain ink.

[0057] There are no particular restrictions on the volume-average particle size of the resin particles, but from the standpoint of obtaining good fixation and high image hardness, it is preferably 10 nm to 1,000 nm, more preferably 10 nm to 200 nm, and particularly preferably 10 nm to 100 nm. The volume-average particle size can be measured, for example, using a particle size analyzer (NanoTrac Wave-UT151, manufactured by MicroTrac-Bell Co., Ltd.).

[0058] There are no particular restrictions on the content of the resin in the ink, but from the viewpoint of fixability and storage stability of the ink, it is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

[0059] —Additives— The ink in the ink set of the present invention may optionally contain surfactants, antiseptics, rust inhibitors, pH adjusters, and the like.

[0060] (Surfactants) As the surfactant, the same surfactant as that described as a component of the cleaning solution can be used.

[0061] (preservative and fungicide) As a preservative and antifungal agent, the same preservative and antifungal agent as described above as an ingredient in the cleaning solution can be used.

[0062] (pH adjuster) As the pH adjusting agent, the same pH adjusting agent as described above as a component of the washing solution can be used.

[0063] (Alkaline earth metal ions) The ink in the ink set of the present invention may optionally contain alkaline earth metal ions. The aforementioned alkaline earth metal ions are not particularly limited and can be appropriately selected depending on the purpose, for example, calcium ions and magnesium ions.

[0064] The content of the alkaline earth metal ions in the ink is preferably 50 ppm or less, and more preferably 30 ppm or less, because they may dissolve the silicone resin in the ink-repellent layer.

[0065] The physical properties of the ink of the present invention are not particularly limited and can be appropriately selected depending on the purpose, but for example, viscosity, surface tension, pH, etc. are preferably within the following ranges.

[0066] While there are no particular limitations on the viscosity of the ink in the ink set of the present invention at 25°C, it is preferably 0.5 mPa·s to 30 mPa·s, more preferably 2 mPa·s to 25 mPa·s, and even more preferably 5 mPa·s to 25 mPa·s, from the standpoint of improving print density and character quality, and obtaining good ejection performance. The viscosity can be measured, for example, using a rotational viscometer (RE-80L, manufactured by Toki Sangyo Co., Ltd.). The measurement conditions are 25°C, standard cone rotor (1°34'×R24), sample volume of 1.2 mL, rotation speed of 50 rpm, and measurement can be performed for 3 minutes.

[0067] While there are no particular limitations on the surface tension of the ink in the ink set of the present invention at 25°C, it is preferably 35 mN / m or less, and more preferably 32 mN / m or less, from the viewpoint that the ink levels well on the recording medium and the drying time of the ink is shortened.

[0068] While there are no particular limitations on the pH of the ink in the ink set of the present invention at 25°C, a pH of 6 to 12 is preferred, and 7 to 11 is more preferred, from the viewpoint of preventing corrosion of metal components that come into contact with the liquid.

[0069] [Inkjet System] The present invention provides an inkjet system comprising: an ink container for containing ink; an ink ejection head for ejecting the ink; an ink supply path connecting the ink ejection head and the ink container; a cleaning solution container for containing a cleaning solution for replacing the ink in the ink ejection head and the ink supply path; and a cleaning solution supply means for supplying the cleaning solution in the cleaning solution container to the ink supply path and the ink ejection head, wherein the ink and cleaning solution are the ink and cleaning solution in the cleaning solution and ink set of the present invention. The system also includes other means as needed.

[0070] Preferably, the inkjet system of the present invention includes means for supplying the cleaning solution of the present invention to the ink supply path and the ink ejection head, thereby replacing the ink in the ink supply path and the ink ejection head with the cleaning solution, if ink is not continuously supplied to the ejection head within a preset time.

[0071] <Recording medium> In this invention, the recording medium refers to an object that is recorded using the inkjet system of the present invention. The aforementioned recording medium refers to a material to which ink or various processing solutions can be temporarily attached. The recording medium is not particularly limited, but examples include plain paper, glossy paper, specialty paper, cloth, film, OHP sheets, general-purpose printing paper, etc. The recording medium is not limited to those commonly used as recording media; building materials such as wallpaper, flooring, and tiles, fabrics for clothing such as T-shirts, textiles, leather, etc., can be used as appropriate. Furthermore, by adjusting the configuration of the transport path for the recording medium, ceramics, glass, metal, etc., can also be used.

[0072] <Records> In this invention, a recorded material can be obtained by recording data using a recording device and recording method equipped with the inkjet system of the present invention. The recorded material has an image or the like formed on the recording medium using the inkjet system of the present invention.

[0073] <Recording device, recording method> The recording apparatus and recording method in the present invention refer to an apparatus equipped with the inkjet system of the present invention capable of ejecting ink, various processing liquids, etc., onto a recording medium, and a method of recording using the apparatus. The ink set of the present invention can be suitably used in various recording devices using an inkjet recording method, such as printers, facsimile machines, copying machines, printer / fax / copier combination machines, and 3D modeling devices.

[0074] The recording device may include not only a head for ejecting ink, but also means for feeding, transporting, and ejecting the recording medium, as well as other devices referred to as pre-processing devices and post-processing devices.

[0075] The recording device and the recording method may include heating means for the heating step and drying means for the drying step. The heating means and drying means include, for example, means for heating and drying the printed surface and the back surface of the recording medium. There are no particular limitations on the heating means and the drying means; for example, a hot air heater and an infrared heater can be used. The heating means and the drying means can be used before, during, or after printing.

[0076] The aforementioned recording device and recording method are not limited to those that visualize meaningful images such as characters or figures using ink. For example, they also include those that form patterns such as geometric designs, and those that create three-dimensional images.

[0077] Unless otherwise specified, the recording device includes both serial type devices that move the discharge head and line type devices that do not move the discharge head. Furthermore, the recording devices include not only desktop types, but also wide-format recording devices capable of printing on A0-sized recording media, and continuous-feed printers that can use, for example, continuous paper wound in a roll as a recording medium.

[0078] The recording device may include not only an ink ejection unit, but also devices referred to as pre-treatment devices, post-treatment devices, and the like. One embodiment of the aforementioned pre-treatment device and post-treatment device is to add a liquid storage unit and a liquid ejection head containing a cleaning solution, a pre-treatment solution, and a post-treatment solution, similar to the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), and to eject the pre-treatment solution and post-treatment solution using an inkjet recording method. Another embodiment of the aforementioned pre-processing apparatus and post-processing apparatus is one in which a pre-processing apparatus and post-processing apparatus are provided that use a method other than the inkjet recording method, such as a blade coating method, a roll coating method, or a spray coating method.

[0079] If a printer equipped with the inkjet system of the present invention is not in continuous operation for a preset period of time, replacing the ink with the cleaning solution of the present invention can prevent the ink from coming into contact with the print head and other units and components for an extended period, thereby reducing the risk of corrosion. Examples of materials that can corrode include metals, and areas where metals are used include the print head housing and the connectors of the ink supply system, with stainless steel (SUS) being a common metal material. Furthermore, the cleaning solution of the present invention has a low risk of corrosion even when in contact with the print head and other components for extended periods. It is preferable to replace the ink with the cleaning solution when the printer is not in continuous operation for 1 to 3 weeks, and it is even more preferable to replace the ink with the cleaning solution when the printer is not in continuous operation for 2 to 1 week.

[0080] Performing a wiping action simultaneously with replacing the ink with a cleaning solution is preferable because it reduces clogging of the nozzle holes in the print head.

[0081] After replacing the ink with cleaning solution, repeating the wiping and emptying of the cleaning solution multiple times further reduces the likelihood of clogging of the nozzle holes in the print head, which is even preferable.

[0082] The three-dimensional molding apparatus for creating the three-dimensional object can be any known apparatus and is not particularly limited, but for example, one equipped with means for containing ink, supplying ink, dispensing ink, drying ink, etc., can be used. The three-dimensional object includes three-dimensional objects obtained by applying ink in multiple layers. It also includes molded products made by processing a structure on which ink has been applied to a substrate such as a recording medium. The molded products are, for example, made by subjecting a recording material or structure formed in the form of a sheet or film to a molding process such as heat stretching or punching, and are suitably used in applications where the surface is decorated before molding, such as meters and control panels for automobiles, office automation equipment, electrical and electronic equipment, cameras, etc.

[0083] Below, an example of a recording device will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the recording device. Figure 2 is a perspective view of the main tank. Image forming apparatus 400, as an example of a recording device, is a serial-type image forming apparatus. A mechanism unit 420 is provided inside the outer casing 401 of the image forming apparatus 400. The ink storage sections 411 of the main tanks 410 (410k, 410c, 410m, 410y) for each color, black (K), cyan (C), magenta (M), and yellow (Y), are formed from packaging materials such as aluminum laminate film. The ink storage sections 411 are housed in, for example, plastic storage container cases 414. Thus, the main tanks 410 are used as ink cartridges for each color. Meanwhile, a cartridge holder 404 is provided at the back of the opening when the cover 401c of the main body of the device is opened. The main tank 410 is detachably mounted on the cartridge holder 404. As a result, the ink outlets 413 of the main tank 410 and the ejection heads 434 for each color are connected via supply tubes 436 for each color, enabling ink to be ejected from the ejection heads 434 to the recording medium.

[0084] The ink of the present invention has no particular limitations on its use and can be appropriately selected according to the purpose. For example, it can be applied to printed materials, paints, coatings, and undercoats. Furthermore, it can be used not only as an ink to form two-dimensional characters and images, but also as a material for forming three-dimensional objects (three-dimensional sculptures).

[0085] In the terminology of this invention, image formation, recording, printing, and the like are all synonymous. [Examples]

[0086] Examples and comparative examples of the present invention are shown below, but the present invention is not limited to these.

[0087] <Preparation of cleaning solution> The composition of the cleaning solution is shown in Table 1. The values ​​in the table represent mass percent. Each component was placed in a container to obtain the composition shown in Table 1, stirred for 2 hours, and then filtered through a membrane filter with a pore size of 0.45 μm to obtain washing solutions 1 to 12. • Water (ion-exchanged water) • Propylene glycol (manufactured by Fujifilm Wako Pure Chemical Corporation) • Glycerin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • 1,2-Ethanediol (manufactured by Sankyo Co., Ltd.) • Dipropylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) • 1,3-Propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) • 2-Pyrrolidone (manufactured by Mitsubishi Chemical Corporation) • ε-Caprolactam (manufactured by Ube Industries, Ltd.) • 3-Ethyl-3-hydroxymethyloxetane (manufactured by Tokyo Chemical Industry Co., Ltd.) • 1,2,3-Benzotriazole (manufactured by Johoku Chemical Industry Co., Ltd.) • Proxel LV (manufactured by Abyssia) • LS-106 (manufactured by Kao Corporation) • Sodium hydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Corporation) • 2-amino-2-ethyl-1,3-propanediol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • N-cyclohexyl-2-aminoethanesulfonic acid (manufactured by Dojin Chemical Laboratories Co., Ltd.) • Dilute nitric acid (manufactured by Kanto Chemical Co., Ltd.)

[0088] The pH and electrical conductivity of the obtained washing solution were measured. The pH was measured using a multi-purpose water quality meter (manufactured by Toa TDK Corporation) at a constant temperature of 25°C. The aforementioned electrical conductivity was measured using a multi-purpose water quality meter (manufactured by Toa TDK Corporation). The measured values ​​are listed in Table 1.

[0089] [Table 1]

[0090] <Ink preparation> The ink formulation is shown in Table 2. The following materials were placed in a container to obtain the compositions shown in Table 2, stirred for 2 hours, and then filtered through a membrane filter with a pore size of 0.45 μm to obtain inks 1 to 12. • Water (ion-exchanged water) • Propylene glycol (manufactured by Fujifilm Wako Pure Chemical Corporation) • Glycerin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Dipropylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) • 2-Pyrrolidone (manufactured by Mitsubishi Chemical Corporation) • ε-Caprolactam (manufactured by Ube Industries, Ltd.) • 1,2,3-Benzotriazole (manufactured by Johoku Chemical Industry Co., Ltd.) • Proxel LV (manufactured by Abyssia) · Bk39 (CI Reactive Black 39) • Red24 (CI Reactive Red 24) • Red245 (CI Reactive Red 245) • Or13 (CI Reactive Orange 13) · Bl49 (CI Reactive Blue 49) • Y95 (CI Reactive Yellow 95) • Bk5 (CI Reactive Black 5) • Direct Bl199 (CI Direct Blue 199) • Acid Bk 172 (CI Acid Black 172) Acid Red 249 (CI Acid Red 249)

[0091] [Table 2]

[0092] The following inks 13, 14, and 15 were used as pigment inks. Inks 13 and 14 are inks containing resin. Ink 13: LX100 / LX101 latex ink cartridge, white ink (manufactured by Mimaki Engineering Co., Ltd., part number: LX100-W-22), which contains resin. Ink 14: HP 831B 775-ml Magenta Latex Ink Cartridge (HP, Part Number: CZ690A), which contains resin. Ink 15: Garment ink, CGX-4W50 white ink (manufactured by Brother Industries, Ltd.)

[0093] Using the above-mentioned cleaning solutions 1-12 and inks 1-15, cleaning tests of the inks with the cleaning solutions were conducted according to the following test methods in the combinations shown in Table 3 below. Fill a syringe with 20 ml of ink and fill a tube with an inner diameter of 1 mm and a length of 50 cm. Next, fill a syringe with 50 ml of cleaning solution. Extrude the ink from the tube filled with ink using 50 ml of cleaning solution and observe whether the color of the ink can be confirmed. The evaluation results were assessed according to the following evaluation criteria. The evaluation results are shown in Table 3. (Evaluation Criteria) ○: It was transparent. △: The ink color was confirmed.

[0094] [Table 3]

[0095] (Examples 1-6, Comparative Examples 1-6) For cleaning solutions 1 to 12, 30 ml of the cleaning solution and a cylindrical piece of SUS303 with a diameter of 10 mm and a length of 40 mm were placed in a polypropylene container. The container was stored at 50°C for 7 days, after which the cylindrical SUS303 was removed at room temperature, the degree of corrosion was observed, and the amount of Fe leached from each cleaning solution was measured. The amount of Fe eluted was measured using ICPE-9000 (manufactured by Shimadzu Corporation). The evaluation results are shown in Table 4.

[0096] In addition, the following ejection tests were performed using a Ricoh inkjet head MH5241F. The inkjet head was filled with cleaning solution and stored at 50°C for 7 days. The cleaning solution was removed from the inkjet head, and the inkjet head was cleaned using a cleaning solution similar to the one that was filled, but stored at room temperature. Ink 1 was ejected from the inkjet head, and the ink ejection status was evaluated using the following evaluation criteria, with the evaluation index being whether the ejected droplets landed in the correct position (landing accuracy). The evaluation results are shown in Table 4. Furthermore, ejection tests using inks and ink heads stored at room temperature confirmed that there were no problems with the ejection of each ink.

[0097] (Evaluation Criteria) ○: When the largest deviation of the droplet from its normal position in any direction (front, back, left, or right) lands within a range of 5 droplets or less: △: When the largest deviation of the droplet from its normal position in the front, back, left, or right is between 5 and 15 droplets. ×: If the number of droplets exceeds 15 in any direction (front, back, left, or right) compared to the normal position.

[0098] [Table 4]

[0099] (Examples 7-12, Comparative Examples 7-12) After filling Ricoh inkjet heads MH5241F with the inks shown in Table 5, the ink was replaced with the cleaning solutions shown in Table 5 in Examples 7-12, while in Comparative Examples 7-12, the ink was not replaced with the cleaning solutions and the heads were stored at 30°C with the inks still inside. The amount of iron leached from the filled ink was measured after 1, 3, and 5 days. The results of observing the appearance of the heads after 5 days at 30°C are shown in Table 5. (Evaluation Criteria) ○: No change △: The metal part has turned brown. ×: Corrosion present

[0100] Furthermore, an ink ejection test similar to the one performed in Example 1 was conducted, and the ink ejection status was evaluated using the same evaluation criteria as in Example 1. The evaluation results are shown in Table 5.

[0101] [Table 5]

[0102] Examples of the present invention are as follows: (1) A cleaning solution comprising water and an organic solvent containing a compound having two or more carbon atoms and two or three OH groups, The pH is between 7 and 10. The phosphate ion concentration is between 100 ppm and 5000 ppm. The proportion of the organic solvent in the total amount of the cleaning solution is 5% by mass or more and 20% by mass or less. The proportion of the compound having two or three OH groups in the total amount of the organic solvent is 60% by mass or more and 100% by mass or less. A cleaning solution characterized by the following features. (2) The cleaning solution according to (1) above, comprising at least one compound selected from the group consisting of propylene glycol, glycerin, 1,2-ethanediol, and dipropylene glycol, which has two or more carbon atoms and two or three OH groups. (3) The cleaning solution according to (1) or (2) above, wherein the organic solvent contains a compound having an amide group-containing ring structure. (4) The washing solution according to (3) above, wherein the compound having the amide group-containing ring structure is 2-pyrrolidone and / or ε-caprolactam. (5) A set of cleaning solution and ink characterized by combining the cleaning solution described in any one of the above items (1) to (4) with ink. (6) A set of the cleaning solution and ink described in (5) above, wherein the ink is a dye ink. (7) A set of cleaning solution and ink as described in (6) above, wherein the dye in the dye ink is a dye compound having a vinyl sulfone group. (8) comprising an ink container for containing ink, an ink ejection head for ejecting the ink, an ink supply path connecting the ink ejection head and the ink container, a cleaning liquid container for containing a cleaning liquid for replacing the ink in the ink ejection head and the ink supply path, and a cleaning liquid supply means for supplying the cleaning liquid in the cleaning liquid container to the ink supply path and the ink ejection head, An inkjet system characterized in that the ink and the cleaning solution are the ink and the cleaning solution in a set of the cleaning solution and dye ink described in any one of items (5) to (7) above. (9) The inkjet system according to (8) above, further comprising means for supplying the cleaning solution to the ink supply path and the ink ejection head to replace the ink in the ink supply path and the ink ejection head with the cleaning solution if the supply of ink to the ejection head is not performed continuously within a predetermined time. [Explanation of Symbols]

[0103] 400 Image forming apparatus 401 Exterior of the image forming apparatus 401c Cover of the main unit of the device 404 Cartridge Holder 410 Main Tank Main tanks for each color: 410k, 410c, 410m, 410y (Black (K), Cyan (C), Magenta (M), Yellow (Y)) 411 Ink reservoir 413 Ink outlet 414 Storage container case 420 Mechanism Department 434 Discharge head 436 Supply Tube [Prior art documents] [Patent Documents]

[0104] [Patent Document 1] Japanese Patent Publication No. 2011-213846 [Patent Document 2] Japanese Patent Application Publication No. 07-268665

Claims

1. A cleaning liquid contained in a cleaning liquid container, for cleaning the ink ejection head and the ink supply path by supplying the cleaning liquid contained in the cleaning liquid container to the ink ejection head and the ink supply path connecting the ink ejection head and the ink container, thereby replacing the ink in the ink ejection head and the ink supply path, It comprises water and an organic solvent containing a compound having two or more carbon atoms and two or three OH groups, The compound having two or more carbon atoms and two or three OH groups includes at least one selected from the group consisting of propylene glycol, glycerin, 1,2-ethanediol, and dipropylene glycol. The pH is between 7 and 10. The concentration of phosphate ions is between 100 ppm and 5000 ppm. The proportion of the organic solvent in the total amount of the cleaning solution is 5% by mass or more and 20% by mass or less. The proportion of the compound having two or three OH groups in the total amount of the organic solvent is 60% by mass or more and 100% by mass or less. A cleaning solution characterized by the following features.

2. The cleaning solution according to claim 1, wherein the organic solvent comprises a compound having an amide group-containing ring structure.

3. The washing solution according to claim 2, wherein the compound having the amide group-containing ring structure is 2-pyrrolidone and / or ε-caprolactam.

4. A set of cleaning solution and ink, characterized by combining the cleaning solution described in any one of claims 1 to 3 with ink.

5. The set of cleaning solution and ink according to claim 4, wherein the ink is a dye ink.

6. The set of cleaning solution and ink according to claim 5, wherein the dye in the dye ink is a dye compound having a vinyl sulfone group.

7. The device comprises an ink container for containing ink, an ink ejection head for ejecting the ink, an ink supply path connecting the ink ejection head and the ink container, a cleaning liquid container for containing a cleaning liquid for replacing the ink in the ink ejection head and the ink supply path, and a cleaning liquid supply means for supplying the cleaning liquid from the cleaning liquid container to the ink supply path and the ink ejection head. An inkjet system characterized in that the ink and the cleaning solution are the ink and the cleaning solution in the set of cleaning solution and dye ink described in claim 5 or 6.

8. The inkjet system according to claim 7, further comprising means for supplying the cleaning solution to the ink supply path and the ink ejection head to replace the ink in the ink supply path and the ink ejection head with the cleaning solution if ink is not continuously supplied to the ejection head within a predetermined time.

Images