JP2013056454A - Cleaning liquid set, ink set and cleaning method for inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning liquid set of inkjet recording apparatus having good cleaning performance for an ink containing resin fixed to an inkjet head.SOLUTION: The cleaning liquid set of inkjet recording apparatus for cleaning the ink ejection port of an inkjet recording apparatus that forms an image on a recording medium by ejecting an aqueous ink containing at least a binder resin, or a part near the ink ejection port affecting the ink ejection consists of a first cleaning liquid containing a component which lowers the viscosity of the aqueous ink, and a second cleaning liquid different from the first cleaning liquid and containing water or a water soluble organic solvent that dissolves the aqueous ink fixed to the ink ejection port or a part near the ink ejection port affecting the ink ejection.

Description

  The present invention relates to a cleaning liquid set for an ink jet recording apparatus, an ink set for an ink jet recording apparatus, and a method for cleaning an ink jet recording apparatus, which prevent ink sticking.

  The ink jet recording method is a method in which minute ink droplets are ejected by various operating principles and adhered to a recording medium such as paper to record images / characters. It has advantages such as being easy to make. In the ink jet recording method, various improvements have been made in each field of ink, ink jet recording medium, and ink jet recording apparatus, and now, they are rapidly spreading in various fields such as various printers, facsimiles, computer terminals, and the like. In particular, recently, the image quality of printers has been improved and the image quality has been reached.

  As an ink jet printer used in the ink jet recording method, a recording head in which a plurality of recording elements are integrated and arranged is used in order to improve a printing speed, and a plurality of ink discharge ports (nozzle portions) and a plurality of ink liquid paths are integrated. . Furthermore, a printer equipped with a plurality of recording heads having the above-described configuration is often used for color correspondence. In that case, the heads that eject ink of each color are generally arranged in parallel in the main scanning direction.

  In ink jet recording in which micro droplets are ejected, an ink liquid containing a color material is ejected from a thin nozzle onto a recording medium to form an image. Therefore, as one of the color materials, water-soluble water-soluble A dye is used. Such a water-based dye ink has a sharp absorption spectrum and shows a clear color with high purity. Further, since it has no particle property and does not generate scattered light or reflected light, it has characteristics such as high transparency and clear hue. However, an image formed with a dye has a problem that an image that requires high image storage stability cannot be obtained because the durability of the dye itself is low.

  On the other hand, from the viewpoint of obtaining high image storability, an ink jet recording method using a pigment ink using a pigment as a coloring material is known. Aqueous pigment inks are prepared by dispersing pigments in an aqueous medium in the form of fine particles, and the pigments themselves have high light resistance and ozone fading resistance. Can be significantly increased as compared to those using dyes. Water-based pigment inks having such characteristics are widely used mainly in large-format ink jet prints.

  However, in the case of using the ink with the pigment, since the pigment particles are not soaked into the recording medium and are deposited on the surface, there is a problem that the scratch resistance of the formed image surface is inferior. However, the usable period is limited, or it is unavoidable that the surface is further laminated and used.

  As means for improving the scratch resistance of an image formed with such an aqueous pigment ink, an aqueous pigment ink in which a water-soluble resin or a fixing resin (binder resin) is added to the ink is disclosed (Patent Document 1,). Patent Document 2).

  Such a water-based pigment ink is an environment-friendly ink that can be used as a substitute for oil-based inks because it can form an image regardless of whether it is a water-absorbing recording medium or a non-water-absorbing recording medium.

  However, such an ink has a problem that it easily adheres to the inside or the surface of the ink discharge port of an inkjet head having a hydrophobic surface because the water-soluble resin is freely dissolved and dispersed in the ink. .

  A cleaning liquid for ink containing a water-soluble resin is disclosed in Patent Document 3, but the cleaning ability is not sufficient.

JP 2011-098540 A JP 2011-116859 A JP 2009-233911 A

  Accordingly, the present invention has been made to solve the above-described problems, and the problem is that the cleaning liquid set for an ink jet recording apparatus and the ink jet recording apparatus have good cleaning performance with respect to the ink containing the resin fixed to the ink jet head. The present invention provides a cleaning method for an ink jet recording apparatus capable of maintaining an ink set for printing and good ejection performance.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

〔式中、Ｒ_１は炭素数１〜６の直鎖または分岐のアルキル基を表わし、Ｒ_２およびＲ_３は水素原子、または炭素数１〜４の直鎖若しくは分岐のアルキル基を表わし、Ｒ_２とＲ_３は同一であっても異なっていてもよい。〕
６．前記第１の洗浄液が、水及び塩基性化合物を含むことを特徴とする前記１．〜５．の何れかに記載のインクジェット記録装置用洗浄液セット。
７．前記塩基性化合物が、アミン類化合物であることを特徴とする前記６．記載のインクジェット記録装置用洗浄液セット。
８．前記第２の洗浄液に含む水溶性有機溶剤が、溶解度パラメータ（ＳＰ値）が８以上１０以下の範囲であることを特徴とする前記１．〜７．の何れかに記載のインクジェット記録装置用洗浄液セット。
９．前記水溶性有機溶剤が、アルキレングリコールアルキルエーテルであることを特徴とする前記８．記載のインクジェット記録装置用洗浄液セット。
１０．前記アルキレングリコールアルキルエーテルが、前記第２の洗浄液中に、５０質量％以上含有することを特徴とする前記９．記載のインクジェット記録装置用洗浄液セット。
１１．前記第２の洗浄液は、水を５質量％以上の範囲で含有することを特徴とする前記１．〜１０．の何れかに記載のインクジェット記録装置用洗浄液セット。
１２．少なくともバインダー樹脂を含有する水性インクと、該水性インクを吐出して記録媒体上に画像を形成するインクジェット記録装置のインク吐出口又はインク吐出口近傍でインク吐出に影響を与える部位を洗浄するためのインクジェット記録装置用洗浄液セットとからなるインクジェット記録装置用インクセットであって、前記インクジェット記録装置用洗浄液が、前記水性インクの粘度を低下させる成分を含有する第１の洗浄液と、前記インク吐出口又はインク吐出口近傍でインク吐出に影響を与える部位で固化した水性インクを溶解させる水溶性有機溶剤を含み、前記第１の洗浄液とは異なる第２の洗浄液と、からなることを特徴とするインクジェット記録装置用インクセット。
１３．前記水性インクのバインダー樹脂が、少なくとも酸性基を有する水溶性樹脂であることを特徴とする前記１２．記載のインクジェット記録装置用インクセット。
１４．前記水溶性樹脂が、酸価が５０ｍｇＫＯＨ／ｇ以上、２００ｍｇＫＯＨ／ｇ以下の範囲のアクリル系樹脂であることを特徴とする前記１３．記載のインクジェット記録装置用インクセット。
１５．前記水溶性樹脂が、アミン類化合物により、部分的に、または完全に、中和されていることを特徴とする前記１３．又は１４．記載のインクジェット記録装置用インクセット。
１６．前記水性インクが、下記一般式（１）で表わされるβ―アルコキシプロピオンアミド類を含むことを特徴とする前記１２．〜１５．の何れかに記載のインクジェット記録装置用インクセット。

〔式中、Ｒ_１は炭素数１〜６の直鎖または分岐のアルキル基を表わし、Ｒ_２およびＲ_３は水素原子、または炭素数１〜４の直鎖若しくは分岐のアルキル基を表わし、Ｒ_２とＲ_３は同一であっても異なっていてもよい。〕
１７．前記第１の洗浄液が、水及び塩基性化合物を含むことを特徴とする前記１２．〜１６．の何れかに記載のインクジェット記録装置用インクセット。
１８．前記塩基性化合物が、アミン類化合物であることを特徴とする前記１７．のインクジェット記録装置用インクセット。
１９．前記水性インクが、界面活性剤を含み、前記第１の洗浄液が、界面活性剤を含まないことを特徴とする前記１２．〜１８．の何れかに記載のインクジェット記録装置用インクセット。
２０．前記第２の洗浄液に含む水溶性有機溶剤が、溶解度パラメータ（ＳＰ値）が８以上１０以下の範囲であることを特徴とする前記１２．〜１９．の何れかに記載のインクジェット記録装置用インクセット。
２１．前記水溶性有機溶剤が、アルキレングリコールアルキルエーテルであることを特徴とする前記２０．記載のインクジェット記録装置用インクセット。
２２．前記アルキレングリコールアルキルエーテルが、前記第２の洗浄液中に、５０質量％以上含有することを特徴とする前記２１．記載のインクジェット記録装置用インクセット。
２３．前記第２の洗浄液は、水を５質量％以上の範囲で含有することを特徴とする前記１２．〜２２．の何れかに記載のインクジェット記録装置用インクセット。
２４．前記１２．〜２３．の何れかに記載のインクジェット記録装置用インクセットを用いたインクジェット記録装置の洗浄方法であって、前記第１の洗浄液を含浸させた吸収部材によって、インク吐出口又はインク吐出口近傍でインク吐出に影響を与える部位に付着した水性インクの粘度を低下させる洗浄を行う第１の洗浄工程と、前記第１の洗浄工程とは異なるタイミングで、前記第２の洗浄液を含浸させた吸収部材によって、インク吐出口又はインク吐出口近傍でインク吐出に影響を与える部位で固化した水性インクを溶解させる洗浄を行う第２の洗浄工程と、を有することを特徴とするインクジェット記録装置の洗浄方法。
２５．前記第１の洗浄工程は、比較的短期の間隔で行い、前記第２の洗浄工程は、比較的中長期的な間隔で行うことを特徴とする前記２４．記載のインクジェット記録装置の洗浄方法。 1. Inkjet recording apparatus cleaning liquid for cleaning an ink ejection port in an inkjet recording apparatus that ejects aqueous ink containing at least a binder resin to form an image on a recording medium or a portion that affects ink ejection in the vicinity of the ink ejection port A first cleaning liquid containing a component that lowers the viscosity of the water-based ink, water that dissolves the water-based ink solidified at a site that affects ink discharge near the ink discharge port or the ink discharge port, and A cleaning liquid set for an ink jet recording apparatus, comprising a second cleaning liquid containing a water-soluble organic solvent and different from the first cleaning liquid.
2. The water-soluble resin having a water-soluble resin having at least an acidic group as the binder resin of the water-based ink. The cleaning liquid set for an inkjet recording apparatus as described.
3. The water-soluble resin is an acrylic resin having an acid value in the range of 50 mgKOH / g or more and 200 mgKOH / g or less. The cleaning liquid set for an inkjet recording apparatus as described.
4). 2. The water-soluble resin is partially or completely neutralized with an amine compound. Or 3. The cleaning liquid set for an inkjet recording apparatus as described.
5. The water-based ink contains β-alkoxypropionamides represented by the following general formula (1): ~ 4. A cleaning liquid set for an ink jet recording apparatus according to any one of the above.

[Wherein, R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, R ₂ and R ₃ represent a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms; ₂ and R ₃ may be the same or different. ]
6). The first cleaning liquid includes water and a basic compound. ~ 5. A cleaning liquid set for an ink jet recording apparatus according to any one of the above.
7). 6. The basic compound is an amine compound. The cleaning liquid set for an inkjet recording apparatus as described.
8). The water-soluble organic solvent contained in the second cleaning liquid has a solubility parameter (SP value) in the range of 8 or more and 10 or less. ~ 7. A cleaning liquid set for an ink jet recording apparatus according to any one of the above.
9. 8. The water-soluble organic solvent is an alkylene glycol alkyl ether. The cleaning liquid set for an inkjet recording apparatus as described.
10. 8. The alkylene glycol alkyl ether is contained in the second cleaning liquid in an amount of 50% by mass or more. The cleaning liquid set for an inkjet recording apparatus as described.
11. The second cleaning liquid contains water in a range of 5% by mass or more. -10. A cleaning liquid set for an ink jet recording apparatus according to any one of the above.
12 An aqueous ink containing at least a binder resin, and an ink discharge port of an ink jet recording apparatus that discharges the aqueous ink to form an image on a recording medium or a portion that affects ink discharge in the vicinity of the ink discharge port An ink set for an ink jet recording apparatus comprising an ink jet recording apparatus cleaning liquid set, wherein the ink jet recording apparatus cleaning liquid contains a first cleaning liquid containing a component that reduces the viscosity of the aqueous ink, and the ink discharge port or An ink jet recording comprising: a second cleaning liquid different from the first cleaning liquid, including a water-soluble organic solvent that dissolves the water-based ink solidified at a site that affects ink discharge near the ink discharge port Ink set for equipment.
13. 12. The water-based resin described in the above 12. The ink set for inkjet recording apparatuses as described.
14 The water-soluble resin is an acrylic resin having an acid value in the range of 50 mgKOH / g or more and 200 mgKOH / g or less. The ink set for inkjet recording apparatuses as described.
15. 12. The water-soluble resin is partially or completely neutralized with an amine compound. Or 14. The ink set for inkjet recording apparatuses as described.
16. The water-based ink contains a β-alkoxypropionamide represented by the following general formula (1): -15. An ink set for an ink jet recording apparatus according to any one of the above.

[Wherein, R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, R ₂ and R ₃ represent a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms; ₂ and R ₃ may be the same or different. ]
17. 12. The above-described 12., wherein the first cleaning liquid contains water and a basic compound. -16. An ink set for an ink jet recording apparatus according to any one of the above.
18. 16. The above-mentioned 17., wherein the basic compound is an amine compound. Ink set for inkjet recording apparatus.
19. 12. The water-based ink described above, wherein the water-based ink contains a surfactant, and the first cleaning liquid does not contain a surfactant. -18. An ink set for an ink jet recording apparatus according to any one of the above.
20. 12. The water-soluble organic solvent contained in the second cleaning liquid has a solubility parameter (SP value) in the range of 8 or more and 10 or less. ~ 19. An ink set for an ink jet recording apparatus according to any one of the above.
21. 20. The water-soluble organic solvent is an alkylene glycol alkyl ether. The ink set for inkjet recording apparatuses as described.
22. The alkylene glycol alkyl ether is contained in the second cleaning liquid in an amount of 50% by mass or more. The ink set for inkjet recording apparatuses as described.
23. The second cleaning liquid contains water in the range of 5% by mass or more. -22. An ink set for an ink jet recording apparatus according to any one of the above.
24. 12. The above. -23. A method for cleaning an ink jet recording apparatus using the ink set for an ink jet recording apparatus according to any one of the above, wherein ink is ejected at or near an ink ejection port by an absorbing member impregnated with the first cleaning liquid. Ink is absorbed by the absorbing member impregnated with the second cleaning liquid at a timing different from the first cleaning step in which cleaning is performed to reduce the viscosity of the water-based ink adhering to the affected site, and the first cleaning step. And a second cleaning step of cleaning the aqueous ink solidified at a portion that affects ink discharge in the vicinity of the discharge port or the ink discharge port.
25. The first cleaning step is performed at a relatively short interval, and the second cleaning step is performed at a relatively medium to long term interval. A method for cleaning an ink jet recording apparatus according to claim 1.

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning liquid set for inkjet recording devices which has favorable washing | cleaning performance with respect to the ink containing resin fixed to the inkjet head, the ink set for inkjet recording devices, and washing | cleaning of the inkjet recording device which can maintain favorable discharge performance A method can be provided. More specifically, the ink set for the ink jet recording apparatus, the ink set for the ink jet recording apparatus, and the ink set for the ink jet recording apparatus capable of preventing the ink from adhering to the ink discharge port or the part affecting the ink discharge and further sufficiently dissolving and cleaning the solidified ink. A cleaning method for an ink jet recording apparatus can be provided.

The figure which shows an example of the washing | cleaning mechanism using a blade-shaped absorption member The figure which shows an example of the washing | cleaning mechanism using a roller-shaped absorption member The figure which shows an example of the washing | cleaning mechanism using a sheet-like absorption member The figure which shows an example of the cleaning mechanism which immerses the discharge port formation surface in cleaning liquid The figure which shows an example of the washing | cleaning mechanism using a cap The figure which shows an example of the washing | cleaning mechanism which supplies a washing | cleaning liquid via an ink flow path.

  Below, the form for implementing this invention is demonstrated.

  The cleaning liquid set for an ink jet recording apparatus of the present invention affects ink discharge at or near the ink discharge port of an ink jet recording apparatus that forms an image on a recording medium by discharging aqueous ink containing at least a binder resin. This is for cleaning the part.

  Therefore, the cleaning liquid set for an ink jet recording apparatus according to the present invention has a good effect in relation to the water-based ink.

  The water-based ink will be described later. First, the first cleaning liquid according to the present invention will be described.

  In the present invention, the first cleaning liquid contains a component that lowers the viscosity of the aqueous ink containing at least the binder resin. That is, when the water-based ink adheres to a portion that affects ink ejection in the vicinity of the ink ejection port or the ink ejection port, the viscosity of the ink is lowered to remove the ink and clean it. Such cleaning is suitable when performed at relatively short intervals (cycles), for example, when it is performed every scan or every time one sheet is output.

  The first cleaning liquid preferably contains water and a basic compound as such components. Thereby, re-dissolution or re-dispersion of the acidic group-containing resin used in the ink is promoted, and the effect of suitably reducing the viscosity of the water-based ink is exhibited.

  The basic compound in the present invention refers to a substance having a pH higher than 7 when dissolved in 0.1 mol / L water. As a pH measurement method, for example, a pH value at 25 ° C. is measured using a digital pH meter HM-30S manufactured by Toa Denpa Kogyo Co., Ltd.

  Examples of the basic compound applicable to the present invention include alkali metal and ammonium hydroxides (for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, etc.), alkali metal carbonates (for example, potassium carbonate, Any of an organic base compound selected from inorganic base compounds selected from alkali metal bicarbonates (for example, potassium hydrogen carbonate and sodium hydrogen carbonate), ammonia, etc., amine compounds, and the like. These can be used alone or in combination of two or more.

  In the present invention, an amine compound is preferably used as the basic compound. This is because when the cleaning liquid is mixed with the ink, the dispersion stability of the pigment dispersion in the ink is unlikely to be impaired, so that the ink can be removed as it is without causing precipitation or the like.

  Examples of amine compounds include triethylamine, N, N-dimethylaminoethanol, N, N-dibutylaminoethanol, N-methyl-diethanolamine, 2-amino-2-methylpropanol, diethanolamine, triethanolamine, and N-methylaminoethanol. N, N-diethylaminoethanol, N, N-dimethylaminoethanol, N, N-dibutylaminoethanol, N-methyl-diethanolamine, 2-amino-2-methylpropanol, N, N -Diethylaminoethanol can be preferably used.

  If necessary, other additives such as a moisturizing agent and an antifungal agent may be added to the first cleaning liquid.

  In the present invention, the first cleaning liquid may contain a water-soluble organic solvent that can be used in the second cleaning liquid described later. The first cleaning liquid preferably has an organic solvent different from the organic solvent contained in the second cleaning liquid, and more preferably does not substantially contain the organic solvent.

  Next, the second cleaning liquid according to the present invention will be described.

  In the present invention, the second cleaning liquid contains water and a water-soluble organic solvent that dissolves the water-based ink solidified in the ink discharge port or in the vicinity of the ink discharge port and affects ink discharge, and the first cleaning liquid Is different.

  The difference from the first cleaning liquid means that a part of the components of the second cleaning liquid may overlap with the components of the first cleaning liquid, but not as a whole.

  In the second cleaning liquid, the water-soluble organic solvent is preferably glycol ethers or 1,2-alkanediols.

  Examples of glycol ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol Monomethyl ether and the like are included.

  Examples of 1,2-alkanediols include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and the like.

  Examples of water-soluble organic solvents include cyclic solvents containing nitrogen or sulfur atoms, cyclic ester solvents, lactic acid esters, β-alkoxypropionamides, alkylene glycol diethers, alkylene glycol monoether monoesters and dimethyl sulfoxide. included.

  Examples of the cyclic solvent containing a nitrogen atom include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, methylcaprolactam, Cyclic amide compounds such as 2-azacyclooctanone are included.

  Examples of the cyclic solvent containing a sulfur atom include a 5- to 7-membered ring compound, preferably sulfolane.

  Examples of the cyclic ester solvent include γ-butyrolactone, ε-caprolactone, and the like. Examples of the lactic acid ester include butyl lactate, ethyl lactate and the like.

  Examples of β-alkoxypropionamide include compounds represented by the following formula (1).

R _{1 in} formula (1) represents a linear or branched alkyl group having 1 to 6 carbon atoms. The linear or branched alkyl group having 1 to 6 carbon atoms is preferably a methyl group, an ethyl group or an n-butyl group.

R ₂ and R _{3 in} the formula (1) each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ₂ and R ₃ may be the same as or different from each other.

  The linear or branched alkyl group having 1 to 4 carbon atoms is preferably a methyl group or an ethyl group.

  Β-alkoxypropionamide represented by the formula (1) has permeability to a recording medium, easily dissolves the binder resin, and has high compatibility with an aqueous solvent.

  Preferred examples of β-alkoxypropionamide include, but are not limited to, 3-butoxy-N, N-dimethylpropionamide (BDMPA), 3-methoxy-N, N-dimethylpropionamide (MDMPA), 3-ethoxy- N, N-diethylpropionamide (EDEPA) and the like are included.

  The β-alkoxypropionamide represented by the formula (1) can be produced, for example, by the method described in JP2009-184079A or WO2008-102615.

  Moreover, as a commercial item of (beta) -alkoxypropionamide represented by Formula (1), Idemitsu Kosan Co., Ltd. brand name: Ecamide etc. are.

  Examples of the alkylene glycol diether include diethylene glycol diethyl ether.

  Examples of the alkylene glycol monoether monoester include diethylene glycol monoethyl monoacetate.

  Among these, β-alkoxypropionamide is preferable, and β-alkoxypropionamide represented by the formula (1) is more preferable.

  Examples of other water-soluble organic solvents include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, Ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), amines (eg, ethanolamine, diethanolamine, triethanolamine, N -Methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine , Diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.) included.

  In the present invention, the water-soluble organic solvent used for the second cleaning liquid has a solvent solubility parameter (SP value) of 8 or more and 10 or less (8.0 to 10.0) from the viewpoint of dispersibility in the fixed ink. It is preferable to include at least one solvent. In addition, the water-soluble organic solvent used in the cleaning liquid preferably contains at least one solvent used in the water-based ink from the viewpoint of affinity with the fixed ink, has an SP value of 8 or more and 10 or less, and It is more preferable to use a solvent used in water-based ink.

The solubility parameter (SP value) of the solvent referred to in the present invention is a value represented by the square root of the molecular aggregation energy, and is described in Polymer HandBook (Second Edition) Chapter IV, Solubility Parameter Values. The unit is (cal / cm ³ ) ^1/2 and refers to the value at 25 ° C.

  In addition, R.D. F. It can be calculated by the method described in Fedors, Polymer Engineering Science, 14, p147 (1967).

  The second cleaning liquid in the present invention preferably contains at least one alkylene glycol alkyl ether as a water-soluble organic solvent.

  Although it does not specifically limit as alkylene glycol alkyl ether, For example, ethylene glycol monomethyl ether (11.6), ethylene glycol monoethyl ether (11.4), ethylene glycol monobutyl ether (9.8), ethylene glycol monoisopropyl ether (9.2), diethylene glycol monomethyl ether (11.6), diethylene glycol monoethyl ether (11.2), diethylene glycol monobutyl ether (9.5), diethylene glycol dimethyl ether (9.4), triethylene glycol monomethyl ether (10. 5), triethylene glycol monoethyl ether (10.4), triethylene glycol monobutyl ether (9.6), propylene glycol monomethyl Ether (10.4), propylene glycol monophenyl ether (9.4), dipropylene glycol monomethyl ether (9.6), tripropylene glycol monomethyl ether (9.6) or the like can be preferably exemplified. The numerical value in the parenthesis represents the SP value.

  Among them, for example, ethylene glycol monobutyl ether (9.8), ethylene glycol monoisopropyl ether (9.2), diethylene glycol monobutyl ether (9.5), diethylene glycol dimethyl ether (9.4), triethylene glycol monobutyl ether (9. 6), propylene glycol monophenyl ether (9.4), dipropylene glycol monomethyl ether (9.6), tripropylene glycol monomethyl ether (9.6) and the like having an SP value of 9.0 or more and less than 12 Glycol alkyl ether can be particularly preferably used. The numerical value in the parenthesis represents the SP value.

  The content of alkylene glycol alkyl ether in the second cleaning liquid is preferably in the range of 50% by mass or more.

  In the present invention, the second cleaning liquid contains water in addition to the water-soluble organic solvent described above.

  The water content in the second cleaning liquid is preferably in the range of 5% by mass to 50% by mass.

  Usually, since the water-soluble organic solvent has hygroscopicity, it may contain some water unless a drying step is provided. Unlike this, this embodiment is characterized in that water is intentionally included. This is because the effect of including water is expressed significantly.

  That is, in the present invention, the second cleaning liquid contains water, and preferably the water content is in the range of 5% by mass or more, so that the permeability to the fixed ink is further increased, and the second cleaning liquid is included in the fixed ink. Since additives such as resins and surfactants are more easily dissolved in the second cleaning liquid, the head member has an outstandingly excellent cleaning performance. Also, since the ink fixed to the head member is more hydrophobic than the original ink, the second cleaning liquid should be made hydrophobic by reducing the water content compared to the first cleaning liquid. More specifically, the water content is more preferably 50% by mass or less. Thereby, there is an effect that ink ejection is further stabilized.

  The second cleaning liquid according to the present invention may contain other additives such as a surfactant, a moisturizing agent, and an antifungal agent as necessary.

  In the present invention, the second cleaning liquid may contain a basic compound that can be used in the first cleaning liquid described above, but it is more preferable that the second cleaning liquid does not substantially contain the basic compound.

  Next, an aqueous ink targeted by the cleaning liquid set for an ink jet recording apparatus of the present invention, or an aqueous ink for ink jet recording (hereinafter also referred to as ink) constituting the ink set for an ink jet recording apparatus will be described.

  Such an ink of the present invention contains at least a binder resin. The binder resin used in the ink of the present invention has a function of fixing (adhering) the landed ink droplets to the recording medium. In addition, the binder resin is required not only to improve the abrasion resistance and water resistance of the ink film, but also to have a function of increasing gloss and optical density. Therefore, it is more preferable that the binder resin be easily dispersed in an aqueous solvent, have a certain degree of transparency, and have compatibility with other ink components.

  In the present invention, the binder resin preferably has an acidic group, and the acidic group is not particularly limited, but preferred examples include a carboxyl group and a sulfonic acid group.

  By containing a resin component having an acidic group, aggregates are less likely to be generated due to charge repulsion with the pigment dispersion in the ink, so that the dispersion stability of the ink is improved.

  The binder resin used in the ink of the present invention is preferably one that can be dissolved or dispersed in an aqueous solvent, and more specifically, it may be a water-soluble resin or an aqueous dispersion polymer fine particle. preferable. It is more preferable to use a water-soluble resin because of its high solubility and stability in aqueous solvents.

  Water-soluble resins that can be used in the present invention include acrylic resins, styrene-acrylic resins, acrylonitrile-acrylic resins, vinyl acetate-acrylic resins, polyvinyl alcohol resins, polyurethane resins, polyamide resins, and polyester resins. And polyolefin resins. Among these, acrylic resins, polyamide resins, polyvinyl alcohol resins, and polyurethane resins are preferable, and acrylic resins are more preferable.

  The acrylic resin may be a homopolymer of (meth) acrylic acid ester or a copolymer of (meth) acrylic acid ester and another copolymerizable monomer. A copolymer of (meth) acrylic acid ester and another copolymerization monomer is particularly preferred because it has a high degree of freedom in designing the resin structure, is easily synthesized by a polymerization reaction, and is low in cost.

  The content ratio of the structural unit derived from the (meth) acrylic acid ester in the copolymer is preferably 60 to 100% by mass, and 80 to 100% by mass with respect to all monomers constituting the copolymer. It is more preferable.

  Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters. Especially, the alkyl ester of (meth) acrylic acid (The carbon number of alkyl is 1-12) is preferable. The (meth) acrylic acid ester may be one type or two or more types.

  Examples of preferable combinations of two or more kinds of (meth) acrylic acid esters include methyl methacrylate, alkyl acrylate (alkyl has 1 to 12 carbon atoms), and methacrylic acid alkyl ester (alkyl has carbon number 2-12) are included.

  Examples of other copolymerization monomers in the copolymer of (meth) acrylic acid ester and other copolymerization monomers include monomers having acidic groups.

  Examples of the monomer having an acidic group include acrylic acid, methacrylic acid, itaconic acid and the like. Among them, copolymers of (meth) acrylic acid esters and other copolymerization monomers include, as main monomers, methyl methacrylate, alkyl acrylate (alkyl has 1 to 12 carbon atoms), and alkyl methacrylate. (Alkyl has 2 to 12 carbon atoms) is preferably a copolymer obtained by polymerizing a monomer having an acidic group as another copolymer monomer.

  Total of structural units derived from main monomers (methyl methacrylate, alkyl acrylate ester (alkyl has 1 to 12 carbon atoms) and methacrylic acid alkyl ester (alkyl has 2 to 12 carbon atoms)) contained in the copolymer It is preferable that a content rate is 80-95 mass% with respect to all the monomers which comprise a copolymer.

  At least a part of the acidic groups contained in the water-soluble resin is preferably partially or completely neutralized with a base from the viewpoint of enhancing the solubility in an aqueous solvent.

  Examples of the base to be neutralized include alkali metal or alkaline earth metal hydroxides (for example, NaOH, KOH, etc.); amines (for example, alkanolamine, alkylamine, etc.); ammonia and the like. Among them, the resin neutralized with ammonia and / or amines is a resin from which ammonia and / or amines have been removed because ammonia and / or amines evaporate together with the aqueous solvent from the ink after fixing on the recording medium. The solubility of the is reduced. A cured ink film containing such a resin is preferable because it has water resistance. Among them, amines are preferable, and specific examples of amines include triethylamine, N, N-dimethylaminoethanol, 2-di-n-butylaminoethanol, methyldiethanolamine, 2-amino-2-methyl-1-propanol, Examples include diethanolamine, triethanolamine, and 2-methylaminoethanol. In particular, neutralization with amines having a boiling point of less than 200 ° C. is particularly preferable from the viewpoint of improving image durability.

  The acid value of the water-soluble resin used in the present invention is preferably 50 to 200 mgKOH / g, and more preferably 50 to 130 mgKOH / g. If the acid value of the water-soluble resin is less than 50 mgKOH / g, the resin may not be sufficiently soluble in water and may not be sufficiently soluble in an aqueous solvent. On the other hand, if the acid value of the water-soluble resin is more than 200 mgKOH / g, the ink film becomes soft and the abrasion resistance decreases.

  The acid value of the water-soluble resin in the present invention refers to the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the water-soluble resin. The acid value measurement and hydrolysis acid value measurement of JIS K 0070 It can be measured by (total acid value measurement).

  The content of the neutralizing base depends on the acid value and content of the water-soluble resin, but the number of chemical equivalents is 0.5 to 5 times the number of chemical equivalents of acidic groups contained in the water-soluble resin. It is preferable to make it. When the content of the neutralizing base is less than 0.5 times the number of chemical equivalents of the acidic groups contained in the water-soluble resin, the effect of increasing the dispersibility of the water-soluble resin is sufficiently obtained. It may not be possible. On the other hand, if the content of the neutralizing base is more than 5 times the number of chemical equivalents of the acidic groups contained in the water-soluble resin, the water resistance of the ink film is reduced, discoloration, odor, etc. May occur.

The weight average molecular weight (Mw) of the water-soluble resin is preferably 2.0 × 10 ^{4 to} 8.0 × 10 ⁴ , and more preferably 2.5 × 10 ^{4 to} 7.0 × 10 ^4. . If the weight average molecular weight is less than 2.0 × 10 ⁴ , the fixing ability of the ink is small, and the resulting image may not have sufficient abrasion resistance. On the other hand, when the weight average molecular weight (Mw) is more than 8.0 × 10 ⁴ , the viscosity of the ink is too high, and the ejection stability from the nozzle may be lowered.

  It is preferable that the glass transition temperature (Tg) of binder resin is 30-100 degreeC. If the Tg is less than 30 ° C., the resulting image may not have sufficient abrasion resistance, or blocking may occur. On the other hand, when Tg is higher than 100 ° C., it is considered that the ink film after drying becomes too hard and brittle, and the abrasion resistance may be lowered.

  The content of the binder resin is preferably 1 to 15% by mass and more preferably 3 to 10% by mass with respect to the entire ink. When the content of the binder resin is less than 1% by mass, the function of fixing a color material such as a pigment on the recording medium may not be sufficiently obtained. On the other hand, when the content of the binder resin is more than 15% by mass, the viscosity of the ink becomes high and the injection stability may be lowered.

  The water-based ink of the present invention may further contain water-based dispersed polymer fine particles in order to further improve the abrasion resistance of the ink film.

  The water-based dispersed polymer fine particles can be composed of the same water-soluble resin as described above. The average particle size of the water-based dispersed polymer fine particles is preferably 300 nm or less, and more preferably 130 nm or less, from the viewpoint that the nozzle of the head is not clogged and an image having good gloss is obtained. Further, the average particle size of the polymer fine particles is preferably 30 nm or more from the viewpoint of production stability.

  The content of the water-based dispersed polymer fine particles is preferably 0.7% by mass to 6% by mass with respect to the entire ink, from the viewpoint of easy fixing to a recording medium and long-term storage stability of the ink. It is more preferable that it is% -3 mass%.

  The pigment that can be used in the aqueous ink of the present invention may be a known organic pigment or inorganic pigment. Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments; phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, And polycyclic pigments such as quinophthalone pigments; dye lakes such as basic dye type lakes and acid dye type lakes; nitro pigments; nitroso pigments; aniline black; and daylight fluorescent pigments.

  Specific examples of the pigment are shown below, but the present invention is not limited to these exemplified compounds.

  Preferred examples of organic pigments for magenta, red or violet include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 8, C.I. I. Pigment red 12, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 17, C.I. I. Pigment red 22, C.I. I. Pigment red 23, C.I. I. Pigment red 41, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 114, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 148, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 170, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 220, C.I. I. Pigment red 202, C.I. I. Pigment red 222, C.I. I. Pigment red 238, C.I. I. Pigment red 245, C.I. I. Pigment red 258, C.I. I. Pigment red 282, C.I. I. Pigment violet 19, C.I. I. Pigment Violet 23 and the like are included.

  Preferred examples of organic pigments for orange, yellow or brown include C.I. I. Pigment orange 13, C.I. I. Pigment orange 16, C.I. I. Pigment orange 31, C.I. I. Pigment orange 34, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 43, C.I. I. Pigment yellow 55, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 81, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 139, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 153, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 194, C.I. I. Pigment yellow 199, C.I. I. Pigment yellow 213, C.I. I. Pigment Brown 22 and the like are included.

  Preferred examples of organic pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 5, C.I. I. Pigment blue 16, C.I. I. Pigment blue 29, C.I. I. Pigment blue 60, C.I. I. Pigment Green 7 etc. are included.

  Examples of organic pigments for black include C.I. I. Pigment black 5, C.I. I. Pigment black 7 and the like are included. Examples of organic pigments for white include C.I. I. Pigment White 6 etc. are included.

  Examples of inorganic pigments include carbon black and titanium oxide.

  The ink of the present invention may further contain a pigment dispersant in order to enhance the dispersibility of the pigment. Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, and the like.

  The pigment is preferably added to the ink as a pigment dispersion in order to disperse stably. The pigment dispersion may be any dispersion that can be stably dispersed in an aqueous solvent. A pigment dispersion in which a pigment is dispersed with a dispersion resin; a capsule pigment in which the pigment is coated with a water-insoluble resin: a surface-modified, dispersion resin And self-dispersing pigments that can be dispersed without containing.

  The dispersion resin used in the pigment dispersion in which the pigment is dispersed with the dispersion resin is preferably a water-soluble resin. Preferred examples of such water-soluble resins include styrene-acrylic acid-acrylic acid alkyl ester copolymers, styrene-acrylic acid copolymers, styrene-maleic acid copolymers, styrene-maleic acid-acrylic acid alkyl esters. Copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer Polymers and the like are included.

  Further, as a pigment dispersion resin, a water-soluble resin that can be used as the binder resin may be used for dispersion.

  The water-insoluble resin in the capsule pigment in which the pigment is coated with a water-insoluble resin is a resin that is insoluble in water in a weakly acidic to weakly basic range. Specifically, a resin having a solubility in an aqueous solution having a pH of 4 to 10 is 2% or less. Examples of water-insoluble resins include acrylic resins, styrene-acrylic resins, acrylonitrile-acrylic resins, vinyl acetate resins, vinyl acetate-acrylic resins, vinyl acetate-vinyl chloride resins, polyurethane resins, silicone resins Acrylic resins, polyester resins, epoxy resins and the like are included. The average particle diameter of the capsule pigment is preferably about 80 to 200 nm from the viewpoints of ink storage stability, color developability, and the like.

  The capsule pigment (pigment fine particles coated with a water-insoluble resin) can be produced by a known method. For example, a water-insoluble resin is dissolved in an organic solvent (for example, methyl ethyl ketone), and a base component is further added to partially or completely neutralize acidic groups contained in the water-insoluble resin. A pigment and ion-exchanged water are added to the obtained solution and mixed and dispersed. Thereafter, the organic solvent is removed from the obtained solution, and ion-exchanged water is further added as necessary to prepare a capsule pigment. Alternatively, there is a method in which a monomer is added to a solution in which a pigment and a polymerizable surfactant are dispersed and a polymerization reaction is performed to coat the pigment with a resin.

The weight average molecular weight (Mw) of the aforementioned dispersion resin and water-insoluble resin is preferably 3.0 × 10 ^{3 to} 5.0 × 10 ⁵ , more preferably 7.0 × 10 ^{3 to} 2.0 × 10. ⁵ . The glass transition temperature (Tg) of the dispersion resin and the water-insoluble resin is preferably about −30 to 100 ° C., more preferably about −10 to 80 ° C.

  The mass ratio of the pigment to the dispersion resin is preferably 100/150 to 100/30 for the pigment / dispersion resin. From the viewpoint of enhancing the durability of the image, the ejection stability of the ink, and the storage stability, it is more preferably 100/100 to 100/40.

  The pigment can be dispersed by, for example, a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, or the like.

  From the viewpoint of removing the coarse particles of the pigment dispersion and making the particle size distribution of the pigment fine particles uniform, the pigment dispersion is subjected to a centrifugal separation process or a filtration process using a filter before being added to the ink. Also good.

  The self-dispersing pigment may be a commercial product. Examples of commercially available self-dispersing pigments include CABO-JET200, CABO-JET300 (manufactured by Cabot Corp.), Bonjet CW1 (manufactured by Orient Chemical Industries Ltd.), and the like.

  The surfactant has a function of facilitating the wetting and spreading of the aqueous ink on the recording medium. The surfactant that can be used in the present invention is not particularly limited, and anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, and fatty acid salts; polyoxyethylene alkyl ethers, polyoxyethylene alkylallyl Nonionic surfactants such as ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers; Cationic surfactants such as alkylamine salts and quaternary ammonium salts; Silicone surfactants; A fluorine-based surfactant or the like can be used.

  Among the above-mentioned surfactants, the ink can easily spread on a non-water-absorbing recording medium (for example, vinyl chloride sheet) or a low-water-absorbing recording medium (for example, printing paper). An activator or a fluorosurfactant is preferred.

  By including a silicone-based surfactant or a fluorine-based surfactant in the ink of the present invention, the dot diameter of the landed ink droplets can be greatly expanded, and a high-quality image with high density and no unevenness can be formed. Can do.

  Among them, since the fluorosurfactant has a high surface activation ability, the decrease in the surface tension of the ink due to the heat received from the recording medium is larger than the increase in the surface tension of the ink due to the drying in the initial drying stage of the ink. it is conceivable that. Therefore, the fluorosurfactant is particularly preferably used because it can maintain or reduce the surface tension in the initial drying stage of the ink. If the surface tension of the ink at the initial drying stage (weight change rate is about 5%) is lower than the surface tension of the ink before heating, even if the ink lands so as to overlap the ink droplets that have already landed on the recording medium, The gloss is improved because a smooth ink film can be formed.

  Another method for reducing the surface tension of the ink at the initial stage of drying of the ink is to make the content of the surfactant in the ink before heating be equal to or lower than the critical micelle concentration (CMC).

  The critical micelle concentration is obtained by measuring the change in the surface tension of the ink at each content using a surface tension meter while sequentially increasing the content (concentration) of the surfactant in the ink. That is, when the surfactant concentration is plotted on the horizontal axis and the surface tension of the ink at each surfactant concentration is plotted on the vertical axis, the surface tension of the ink is almost constant within the error range above a certain surfactant concentration. Value. The concentration of the surfactant at this time is defined as the critical micelle concentration. Since the surface tension of the ink tends to decrease until the surfactant concentration reaches the critical micelle concentration, if the surfactant concentration in the ink is the critical micelle concentration, the surface tension at the initial drying stage of the ink is reduced. Can be maintained or reduced.

  The critical micelle concentration in the ink varies depending on the type of surfactant contained in the ink, the type of organic solvent, and the content thereof, but is a constant value at least if the ink composition is the same. The critical micelle concentration in the ink of the present invention may be in the range of about 0.1 to 0.5% by weight based on the total ink.

  These surfactants may be used alone or in combination of two or more.

  Further, these surfactants are preferably used in combination with a water-soluble organic solvent having a low surface tension.

  Preferred examples of the silicone-based surfactant include a polyether-modified polysiloxane compound. Examples of commercially available products include KF-351A and KF-642 manufactured by Shin-Etsu Chemical Co., Ltd., BYK345 and BYK347 manufactured by Big Chemie. , BYK348 and the like.

  The fluorine-based surfactant may be a compound in which at least a part of hydrogen atoms bonded to the carbon atoms constituting the hydrophobic group is substituted with a fluorine atom in a normal surfactant. Of these, a fluorosurfactant having a perfluoroalkyl group is preferred.

  Examples of commercially available fluorosurfactants include DIC's product name: Megafac F, Asahi Glass Co., Ltd. Product name: Surflon, Minnesota Mining and Manufacturing Company Name: Fluorad FC, manufactured by Imperial Chemical Industry Co., Ltd. Product name: Monflor, manufactured by EI Dupont Nemeras & Company, Inc. Product name: Zonyls, Farbevelke Hoechst : Licobet VPF, Neos Co., Ltd. Trade name: Footagent, Big Chemie Co., Ltd. Trade name: BYK340 (surface conditioner, fluorine-modified polymer) and the like.

  The content of the surfactant is such that the surface tension of the ink is within the range described below (in order to allow the ink to wet and spread well even on a coated paper or resin recording medium whose surface energy is lower than that of ordinary paper) It is preferable to adjust so that it may become 15 mN / m or more and less than 35 mN / m. Specifically, the content is preferably 0.01% by mass or more and less than 2.0% by mass with respect to the entire ink.

  In the present invention, the water-based ink contains an aqueous solvent, and examples of the aqueous solvent include a mixture of water and a water-soluble organic solvent.

  The water-soluble organic solvent uniformly distributes the water-soluble resin and other ink components even when the proportion of the water-soluble organic solvent contained in the ink film is relatively large with respect to water, as in the late stage of drying of the ink. It is preferable to use one that can be dispersed or dissolved.

  Examples of the water-soluble organic solvent that can be used in the present invention include (A) a water-soluble organic solvent having a low surface tension; and (B) a recording medium (such as a vinyl chloride sheet) made of a hydrophobic resin. Water-soluble organic solvents that swell are included.

  (A) A water-soluble organic solvent having a low surface tension can easily spread ink even on a non-water-absorbing recording medium (for example, a vinyl chloride sheet) or a low water-absorbing recording medium (for example, a printing paper). Specifically, the water-soluble organic solvent having a low surface tension is preferably a water-soluble organic solvent having a surface tension at 25 ° C. of 45 mN / m or less.

  Such water-soluble organic solvents are preferably glycol ethers or 1,2-alkanediols. Examples of glycol ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol Monomethyl ether and the like are included. Examples of 1,2-alkanediols include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and the like.

  The content of the water-soluble organic solvent having a low surface tension is preferably 1 to 30% by mass with respect to the entire ink. This is because if it is less than 1% by mass, wetting and spreading on the recording medium is not sufficient, and if it exceeds 30% by mass, the drying property is poor and the image is blurred.

  (B) A water-soluble organic solvent that dissolves, softens, or swells a recording medium (such as a vinyl chloride sheet) made of a hydrophobic resin imparts ink permeability, and allows adhesion of the ink film to the recording medium and abrasion resistance. Can increase sex.

  Examples of such water-soluble organic solvents include cyclic solvents containing nitrogen or sulfur atoms, cyclic ester solvents, lactic acid esters, β-alkoxypropionamides, alkylene glycol diethers, alkylene glycol monoether monoesters and dimethyl sulfones. Xoxides and the like are included.

  Examples of the cyclic solvent containing a nitrogen atom include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, methylcaprolactam, Cyclic amide compounds such as 2-azacyclooctanone are included. Examples of the cyclic solvent containing a sulfur atom include a 5- to 7-membered ring compound, preferably sulfolane.

  Examples of the cyclic ester solvent include γ-butyrolactone, ε-caprolactone, and the like. Examples of the lactic acid ester include butyl lactate, ethyl lactate and the like.

  Examples of β-alkoxypropionamide include compounds represented by the following formula (1).

R _{1 in} formula (1) represents a linear or branched alkyl group having 1 to 6 carbon atoms. The linear or branched alkyl group having 1 to 6 carbon atoms is preferably a methyl group, an ethyl group or an n-butyl group.

R ₂ and R _{3 in} the formula (1) each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ₂ and R ₃ may be the same as or different from each other. The linear or branched alkyl group having 1 to 4 carbon atoms is preferably a methyl group or an ethyl group.

  Β-alkoxypropionamide represented by the formula (1) has permeability to a recording medium, easily dissolves the binder resin, and has high compatibility with an aqueous solvent. Preferred examples of β-alkoxypropionamide include, but are not limited to, 3-butoxy-N, N-dimethylpropionamide (BDMPA), 3-methoxy-N, N-dimethylpropionamide (MDMPA), 3-ethoxy- N, N-diethylpropionamide (EDEPA) and the like are included.

  The β-alkoxypropionamide represented by the formula (1) can be produced, for example, by the method described in JP2009-184079A or WO2008-102615. Moreover, as a commercial item of (beta) -alkoxypropionamide represented by Formula (1), Idemitsu Kosan Co., Ltd. brand name: Ecamide etc. are.

  Examples of the alkylene glycol diether include diethylene glycol diethyl ether. Examples of the alkylene glycol monoether monoester include diethylene glycol monoethyl monoacetate.

  Of these, β-alkoxypropionamide is preferable, and β-alkoxypropionamide represented by the formula (1) is more preferable from the viewpoint of easy wettability and penetration even on a non-water-absorbing recording medium. Since β-alkoxypropionamide can further stably dissolve a water-soluble resin in the ink, good adhesion to a recording medium can be obtained, and a high-quality image having glossiness, abrasion resistance and repellency resistance can be obtained. Easy to obtain. Moreover, the kind of water-soluble organic solvent combined and the freedom degree of usage-amount are also large. Further, since the ink has permeability to the recording medium, the ink is easily dried. As a result, the ink droplets can remain at the landing position on the recording medium, and liquid dipping and color bleeding can be suppressed.

  The content of the water-soluble organic solvent that dissolves, softens or swells the recording medium made of a hydrophobic resin is preferably 0.1% by mass or more and less than 40% by mass with respect to the entire ink, and is 1 to 20% by mass. More preferably. When the content is less than 0.1% by mass, the effect of softening or swelling the recording medium may not be sufficiently obtained. When the content is 40% by mass or more, the printer member may be swollen or deteriorated.

  The aqueous solvent that can be used in the present invention may further contain another water-soluble organic solvent, if necessary. Examples of other water-soluble organic solvents include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, Ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), amines (eg, ethanolamine, diethanolamine, triethanolamine, N -Methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine , Diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.) included.

  The total amount of the aqueous solvent may be adjusted so that the surface tension and viscosity of the ink are in the ranges described later, and for example, it is preferably about 1 to 85% by mass with respect to the entire ink.

  The content of the aqueous organic solvent in the ink of the present invention is preferably such that the aqueous organic solvent is contained to such an extent that the binder resin can be dissolved or dispersed even in the ink film after all the water has evaporated.

  The ink of the present invention may further contain other components as necessary. Examples of other components include preservatives, antifungal agents, rust inhibitors, antifoaming agents, viscosity modifiers, penetrants, pH adjusters, drying inhibitors (eg urea, thiourea, ethylene urea, etc.), etc. included.

  The antiseptic and the antifungal agent have a function of maintaining the storage stability of the ink for a long period of time. The preservative and the antifungal agent are not particularly limited, and for example, aromatic halogen compounds (for example, Preventol CMK), methylene dithiocyanate, halogen-containing nitrogen sulfur compounds, 1,2-benzisothiazolin-3-one (for example, PROXEL) GXL).

  The ink of the present invention is suitable for printing on plain paper, coated paper, inkjet dedicated paper, and the like, but is particularly suitable for printing on non-absorbent media such as vinyl chloride sheets.

  Examples of the non-water-absorbing recording medium include a polymer sheet, a board (for example, soft vinyl chloride, hard vinyl chloride, acrylic plate, polyolefin, etc.), glass, tile, rubber, and synthetic paper. Examples of the low-absorbency or absorbent recording medium include plain paper (for example, copy paper, plain paper for printing), coated paper, art paper, ink jet exclusive paper, ink jet glossy paper, cardboard, wood and the like.

  In particular, a preferable non-water-absorbing recording medium capable of obtaining a good image and high image fastness is a recording medium having at least polyvinyl chloride on the recording surface side.

  Specific examples of the recording medium made of polyvinyl chloride include SOL-371G, SOL-373M, SOL-4701 (manufactured by Big Technos Co., Ltd.), glossy vinyl chloride (manufactured by Systemgraph Co., Ltd.), KSM-VS, KSM- VST, KSM-VT (above, Kimoto Co., Ltd.), J-CAL-HGX, J-CAL-YHG, J-CAL-WWWG (above, Kyosho Osaka Co., Ltd.), BUS MARK V400 F vinyl, LITEcal V -600F vinyl (above, manufactured by Flexcon), FR2 (manufactured by Hanwha), LLBAU13713, LLSP20133 (above, manufactured by Sakurai Co., Ltd.), P-370B, P-400M (above, manufactured by Kambo Plus Co., Ltd.), S02P, S12P, S13P , S14P, S22P, S24P, S34P, 27P (above, manufactured by Grafityp), P-223RW, P-224RW, P-249ZW, P-284ZC (above, manufactured by Lintec Corporation), LKG-19, LPA-70, LPE-248, LPM-45, LTG- 11, LTG-21 (above, manufactured by Shinsei Co., Ltd.), MPI3023 (produced by Toyo Corporation), Napoleon Gloss PVC (made by Futatsu Electronics Co., Ltd.), JV-610, Y-114 (above, IKEC Co., Ltd.) Manufactured), NIJ-CAPVC, NIJ-SPVCGT (manufactured by Nichie Corporation), 3101 / H12 / P4, 3104 / H12 / P4, 3104 / H12 / P4S, 9800 / H12 / P4, 3100 / H12 / R2, 3101 / H12 / R2, 3104 / H12 / R2, 1445 / H1 / P3, 1438 / One Way Vision (manufactured by Inetrcoat), JT5129PM, JT5728P, JT5822P, JT5829P, JT5829R, JT5829PM, JT5829RM, JT5929PM (above, manufactured by Mactac), MPI1005, MPI1200MP, MPI1200MP , MPI3500, MPI3501 (above, manufactured by Avery), AM-101G, AM-501G (above, manufactured by Ginichi Co., Ltd.), FR2 (manufactured by Hanwha Japan Co., Ltd.), AY-15P, AY-60P, AY-80P, DBSP137GGH, DBSP137GGL (above, manufactured by Insight Inc.), SJT-V200F, SJT-V400F-1 (above, flat Manufactured by Ory Co., Ltd.), SPS-98, SPSM-98, SPSH-98, SVGL-137, SVGS-137, MD3-200, MD3-301M, MD5-100, MD5-101M, MD5-105 (above, Metamark) 640M, 641G, 641M, 3105M, 3105SG, 3162G, 3164G, 3164M, 3164XG, 3164XM, 3165G, 3165SG, 3165M, 3169M, 3451SG, 3551G, 3551M, 3631, 3641M, 3651G, 3651M, 3651M, 3651G, 3641M (Above, made by Orafol), SVTL-HQ130 (made by Lamy Corporation), SP300 GWF, SPCLEARAD vinyl (above, made by Catalina), R M-SJR (manufactured by Ryoyo Shoji Co., Ltd.), Hi Lucky, New Lucky PVC (above, manufactured by LG), SIY-110, SIY-310, SIY-320 (above, manufactured by Sekisui Chemical Co., Ltd.), PRINT MI Frontlit, PRINT XL Light weight banner (above, manufactured by Endutex), RIJET 100, RIJET 145, RIJET165 (above, manufactured by Ritrama), NM-SG, NM-SM (manufactured by Niei Kaiko Co., Ltd.), LTO3GS (manufactured by Lucio Co., Ltd.) Print 80, Performance print 80 (above, manufactured by Jetgraph Corporation), DSE 550, DSB 550, DSE 800G, DSE 802/137, V250WG, V300WG, V350WG (above, manufactured by Hexis), Di ital White 6005PE, 6010PE (or more, Multifix, Ltd.), and the like.

  In the ink jet recording method using the cleaning liquid set or ink set of the present invention, when recording an image on a recording medium using ink, it is preferable to record by heating at least the recording surface side of the recording medium. Heating improves the drying and thickening speed of the ink and suppresses beading and color bleeding, so that a high-quality recorded image can be obtained, and in addition, the durability of the formed image is easily improved. .

  As the heating temperature, it is preferable to heat the recording medium so that the surface temperature on the recording surface side is 40 ° C. or higher and 80 ° C. or lower. By heating to 40 ° C. or higher, the above effects are likely to be sufficient, and by setting the heating temperature to 80 ° C. or lower, ink ejection is good and stable recording can be easily performed over a long period of time.

  As a heating method, select a method in which a heating heater is incorporated in the recording medium conveyance system or the platen member and heated from the lower side of the recording medium in a contact type, or a method of heating in a non-contact manner from the lower side or the upper side of the recording medium by a lamp or the like. Can do.

  Furthermore, in the ink jet recording method using the cleaning liquid set or ink set of the present invention, it is preferable to use a drying means for the purpose of removing unnecessary organic solvent and the like after recording. The ink drying means is not particularly limited. For example, the recording medium is volatilized by a method in which the back surface of the recording medium is dried by contacting with a heating roller or a flat heater, a means for blowing hot air on the print surface with a dryer, or a decompression process. Methods for removing the components and the like can be appropriately selected or combined.

  Next, an example of a method for cleaning an ink jet recording apparatus using the above-described cleaning liquid set or ink set for an ink jet recording apparatus will be described with reference to FIGS. In the following description, the term “cleaning liquid” may refer to either the first cleaning liquid or the second cleaning liquid.

  FIG. 1 is a diagram for explaining a first aspect of a cleaning method for an ink jet recording apparatus according to the present invention, and shows an example of a cleaning mechanism using a blade-shaped absorbing member.

  In FIG. 1, 1 is an inkjet head, and 11 is an ejection port forming surface on which ejection ports for ejecting ink are formed.

  Further, the cleaning liquid container 3 is filled with the cleaning liquid according to the present invention, and a blade-shaped absorbing member 21 is installed in the cleaning liquid.

  The absorbing member 21 moves while rotating from the positions P1 to P4 by the rotation of the rotating shaft 21a. The position P2 moves in the cleaning liquid, rotates while accompanying the cleaning liquid when moving outside the liquid, starts contact with the discharge port forming surface 11 of the ink jet head 1 at the position P4, and the cleaning liquid is applied to the discharge port forming surface 11. At the same time, the discharge port forming surface 11 is rubbed. As a result, the ink that adheres to or adheres to the ink discharge port on the discharge port forming surface 11 or in the vicinity of the ink discharge port that affects ink discharge is washed. The absorbing member 21 that has been cleaned is immersed again in the liquid at position P2, and the ink or the like adhering to the absorbing member 21 is dissolved and removed by the cleaning liquid.

  In FIG. 1, an example in which one blade-like absorbing member 21 is attached to the rotating shaft 21 a is shown, but a configuration in which a plurality of two, three, four, or the like are installed at regular intervals. You may take it.

  FIG. 2 is a diagram for explaining a second aspect of the cleaning method for an ink jet recording apparatus according to the present invention, and shows an example of a cleaning mechanism using a roller-shaped absorbing member. In the figure, the same reference numerals indicate the same configuration.

  In the example of FIG. 2, a roller-shaped absorbing member 22 is attached to the rotating shaft 22a. Below the roller-shaped absorbing member 22 is disposed so as to be immersed in the cleaning liquid in the cleaning liquid container 3 and absorb the cleaning liquid. Due to the rotation of the rotating shaft 22a, the roller-shaped absorbing member 22 that has absorbed the cleaning liquid contacts the discharge port forming surface 11 of the head 1 to attach the cleaning liquid, and rubs the discharge port forming surface 11. As a result, the ink that adheres to or adheres to the ink discharge port on the discharge port forming surface 11 or in the vicinity of the ink discharge port that affects ink discharge is washed. The absorbing member 22 that has been cleaned is immersed again in the liquid by the rotation of the rotating shaft 22a, and the ink or the like adhering to the absorbing member 22 is dissolved and removed by the cleaning liquid.

  FIG. 3 is a diagram for explaining a third aspect of the cleaning method for an ink jet recording apparatus according to the present invention, and shows an example of a cleaning mechanism using a sheet-like absorbent member. In the figure, the same reference numerals indicate the same configuration.

  3, the sheet-like absorbing member 23 spanned between the three rotary shafts 23 a, 23 b, and 23 c is in contact with the discharge port forming surface 11 of the inkjet head 1, and the cleaning liquid is applied to the discharge port forming surface 11. At the same time, the discharge port forming surface 11 is rubbed. As a result, the ink that adheres to or adheres to the ink discharge port on the discharge port forming surface 11 or in the vicinity of the ink discharge port that affects ink discharge is washed. The sheet-like absorbing member 23 that has been cleaned is rotated by at least one of the three rotating shafts 23a, 23b, and 23c being rotated, and a part thereof is immersed in the cleaning liquid in the cleaning liquid container 3. In the vicinity of the rotating shaft 23c arranged in the above, the ink is immersed again in the cleaning liquid, and the ink and the like adhering to the sheet-like absorbing member 23 is dissolved and removed by the cleaning liquid.

  As described above, as shown in FIGS. 1 to 3, in the present invention, the ink ejection near the ink ejection port or the vicinity of the ink ejection port is affected by the absorbing member impregnated with either the first cleaning liquid or the second cleaning liquid. It is preferable to wash the site which gives Specifically, the absorbing member impregnated with the first cleaning liquid is used to perform cleaning by reducing the viscosity of the water-based ink adhering to the ink discharge port or the part that affects ink discharge, and then cleaning the second cleaning liquid. The impregnated absorbing member solidifies at an ink discharge port or a portion that affects ink discharge, and performs cleaning to dissolve an ink component that cannot be cleaned by the first cleaning liquid. As a result, it is possible to obtain an effect of suppressing the deterioration of the ejection stability due to the dry ink adhering to the ink ejection port or the site that affects the ink ejection.

  In the present invention, the absorbing member is not particularly limited as long as it can absorb the cleaning liquid and can adhere the absorbed cleaning liquid to the discharge port forming surface 11 of the inkjet head 1. A body, a woven fabric, a non-woven fabric, or a fiber assembly such as a brush planted in a rotating body can be preferably exemplified.

  In the present invention, the material of the absorbing member is not particularly limited as long as it is a material that can absorb the cleaning liquid, but is preferably a material that is excellent in absorbability and does not damage the ink jet head member during cleaning, for example, a cloth of ultrafine fibers. Or a porous urethane sponge is preferable for improving the cleaning efficiency.

  The cleaning method of the present invention is not limited to cleaning using the absorbent member as described above.

  FIG. 4 is a view for explaining a fourth aspect of the cleaning method of the ink jet recording apparatus according to the present invention, and shows an example of a cleaning mechanism for immersing the discharge port forming surface in the cleaning liquid. In the figure, the same reference numerals indicate the same configuration.

  In the example of FIG. 4, the discharge port forming surface 11 of the inkjet head 1 is directly immersed in the cleaning liquid in the cleaning liquid tank 4, so that ink is discharged at or near the ink discharge port of the discharge port forming surface 11. The ink adhering to or sticking to the affected part is washed. In order to improve cleaning efficiency, it is also preferable to perform ultrasonic cleaning with the ultrasonic generator 5 while the discharge port forming surface 11 is immersed in the cleaning liquid.

  FIG. 5 is a view for explaining a fifth aspect of the cleaning method for an ink jet recording apparatus according to the present invention, and shows an example of a cleaning mechanism using a cap. In the figure, the same reference numerals indicate the same configuration.

  In the example of FIG. 5, the cap 6 is attached so as to cover the discharge port forming surface 11. Next, the cleaning liquid is introduced from the cleaning liquid tank 7 into the region 61 in the cap 6 through the cleaning liquid supply port 62 provided in the cap 6. As a result, the ejection port forming surface 11 and the cleaning liquid come into contact with each other, and the ink that adheres to or adheres to the ink ejection port on the ejection port forming surface 11 or in the vicinity of the ink ejection port is washed.

  The cleaning liquid in the region 61 in the cap 6 can be replaced with a new cleaning liquid from the cleaning liquid tank 7. A suction pump 63 discharges the cleaning liquid in the region 61 in the cap 6.

  As described above, in the example shown in FIGS. 1 to 5, the cleaning liquid is supplied from the outside of the inkjet head 1 to the ink ejection port on the ejection port forming surface 11 or in the vicinity of the ink ejection port, which affects ink ejection. Although shown, the cleaning method of the present invention is not necessarily limited to this.

  FIG. 6 is a view for explaining a sixth aspect of the method for cleaning an ink jet recording apparatus according to the present invention, and the ink discharge port on the discharge port forming surface 11 or the vicinity of the ink discharge port through the ink flow path in the ink jet head. 1 shows an example of a cleaning method for supplying a cleaning liquid to a part that affects ink ejection. In the figure, the same reference numerals indicate the same configuration.

  In FIG. 6, 12 is an ink tank, 13 is a first cleaning liquid tank for storing a first cleaning liquid, and 14 is a second cleaning liquid tank for storing a second cleaning liquid.

  The ink tank 12, the first cleaning liquid tank 13, and the second cleaning liquid tank 14 are connected to the ink flow path in the inkjet head 1 via the on-off valves 12a, 13a, and 14a, respectively. In other words, the ink flow path in the inkjet head 1 is configured to selectively supply either ink, the first cleaning liquid, or the second cleaning liquid. Thereby, ink is supplied to the ink flow path in the inkjet head 1 during recording, and the first cleaning liquid or the second cleaning liquid is supplied to the ink flow path in the inkjet head 1 during cleaning.

  In this way, it is possible to supply the cleaning liquid via the ink flow path to the ink discharge port on the discharge port forming surface 11 or in the vicinity of the ink discharge port through the ink flow path, and adhere or adhere to the portion. The ink can be washed.

  Further, at the time of cleaning, as shown in the drawing, a suction cap 8 is attached to the discharge port forming surface 11 so as to cover the ink discharge port, and the cleaning liquid in the ink channel is sucked toward the ink discharge port. This is preferable because the cleaning efficiency can be improved. 81 is a suction pump.

  In the cleaning method of the present invention, the first cleaning step with the first cleaning liquid and the second cleaning step with the second cleaning liquid are performed at different timings at an appropriate frequency depending on the environment in which the printer is used and the type of ink. Can be entered.

  The first cleaning step is preferably performed at a relatively short interval, and the second cleaning step is preferably performed at a relatively medium to long term interval. In particular, when the amount of ink used is large or when printing is performed in an environment with low humidity, for example, it is preferable to include the first cleaning step at the start of printing or every several scans of printing. The second cleaning step is used, for example, when the ink stain that has not been removed in the first cleaning step is periodically or manually cleaned or when the printer is stopped for a long period of time. It is preferable to do.

  In this invention, it is preferable that the timing which performs a 2nd washing | cleaning process is immediately after finishing a 1st washing | cleaning process. Specifically, for example, the second cleaning process is performed immediately after wiping off the cleaning liquid in the first cleaning process. For example, it is also preferable to perform the second cleaning step after the first cleaning step and before performing the next ink ejection operation.

  There is no limitation on the inkjet head to which the cleaning liquid set or ink set of the present invention can be applied, and an electro-mechanical conversion system (for example, single cavity type, double cavity type, bender type, piston type, shear mode type, shared wall type) Etc.), electro-thermal conversion method (for example, thermal ink jet type, bubble jet (registered trademark) type, etc.), electrostatic attraction method (for example, electric field control type, slit jet type, etc.) and discharge method (for example, spark jet type) Etc.) can be used. From the viewpoint of the cost and productivity of the inkjet head, it is preferable to use an electro-mechanical conversion type or an electro-thermal conversion type head.

  Examples of the present invention will be described below, but the present invention is not limited to such examples.

Example 1
-Preparation of Cyan Pigment Dispersion 20 parts by mass of Floren TG-750W (solid content 40% by mass, manufactured by Evonik Degussa) was added to 65 parts by mass of ion-exchanged water as a pigment dispersant. To this solution, C.I. I. After adding 15 parts by mass of Pigment Blue 15: 3 and premixing, 0.5% zirconia beads were filled by 50% by volume and dispersed by a sand grinder. Thereby, a cyan pigment dispersion having a pigment solid content of 15% by mass was obtained.

-Preparation of cyan ink C-1 As a water-soluble organic solvent, 9 parts by mass of 1,2-hexanediol (HDO), 5 parts by mass of dipropylene glycol monomethyl ether (DPGME), 3-butoxy-N, N -4 parts by mass of dimethylpropionamide (BDMPA) was added to 20 parts by mass of ion-exchanged water to obtain an aqueous solvent.
To the obtained aqueous solvent, Joncrill JDX-6500 (manufactured by BASF, water-soluble acrylic resin, solid content 29.5 mass%, acid value: 74 mg KOH / g, Tg: 65 ° C., weight average molecular weight 1. 20.3 parts by mass of 0 × 10 ⁴ ) was added and stirred, and the total amount was adjusted to 80 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the prepared cyan pigment dispersion and 0.1 part by mass of BYK-340 as a surfactant were added and stirred.
The obtained solution was filtered with a 0.8 μm filter to obtain cyan ink C-1.

-Formulation of washing liquid As shown below, washing liquids a to k were formulated (Table 1).
Cleaning liquid a: The cleaning liquid a was only 100% by mass of distilled water.
Cleaning liquid b: 40% by mass of 2-pyrrolidone (2-PDN), which is a water-soluble organic solvent, was adjusted to 100% by mass with distilled water to obtain cleaning liquid b.
Cleaning liquid c: Triacetin 3% by mass, which is a water-soluble organic solvent, was adjusted to 100% by mass with distilled water to obtain cleaning liquid c.
Cleaning liquid d: The cleaning liquid d was obtained by changing 40% by mass of triethylene glycol monobutyl ether (TEGBE), which is a water-soluble organic solvent, to 100% by mass with distilled water.
Cleaning solution e: Distilled water was added to a solution of 2% by mass of potassium carbonate, which is a basic compound, and 70% by mass of dipropylene glycol methyl ether (DPGME), which is a water-soluble organic solvent. It was.
Cleaning liquid f: Distilled water was added to 2% by mass of potassium carbonate, which is a basic compound, so as to be 100% by mass to obtain a cleaning liquid f.
Washing liquid g: Distilled water was added to 3% by mass of 2-amino-2-methylpropanol (AMP), which is a basic compound, so as to be 100% by mass to obtain a cleaning liquid g.
Cleaning solution h: Distilled water was added to 100% by mass of 5% by mass of potassium carbonate, which is a basic compound, and 10% by mass of glycerin (Gly), which is a water-soluble organic solvent, to obtain a cleaning solution h.
Cleaning liquid i: 1% by mass of N, N-dimethylaminoethanol as a basic compound, 20% by mass of 2-pyrrolidone (2-PDN) as a water-soluble organic solvent, and glycerin (Gly) 10 as a water-soluble organic solvent Distilled water was added to 100% by mass to make a cleaning liquid i.
Cleaning liquid j: 5% by mass of 2-amino-2-methylpropanol (AMP), which is a basic compound, 2% by mass of dipropylene glycol-n-propyl ether (DPGPE), which is a water-soluble organic solvent, and 100% by mass Distilled water was added so that a washing solution j was obtained.
Cleaning liquid k: 30% by mass of glycerin (Gly) was added to 70% by mass of 2-pyrrolidone (2-PDN), which is a water-soluble organic solvent, to obtain a cleaning liquid k. The water content in the cleaning liquid k is less than 5% by mass.

  The following evaluations were performed using each of the prescribed cleaning liquids a to k as the first cleaning liquid or the second cleaning liquid as shown in Table 2. In addition, evaluation No. In Nos. 10 to 13, the cleaning using the second cleaning liquid described below was omitted.

<Evaluation method of discharge stability 1>
C-1 which is the cyan ink prepared above was loaded into a piezo-type head having a nozzle diameter of 28 μm, a driving frequency of 10 kHz, a nozzle number of 512, a minimum droplet amount of 14 pl, and a nozzle density of 180 dpi. A drive pulse having a pulse width of 5 μsec is applied to the electrodes of the recording head at a voltage adjusted so that the flying speed of the ink droplet is 6 m / sec, and the recording head is driven for three periods (every two ink channels). By doing so, a solid image having a printing rate of 100% was printed on IJ180-10 (manufactured by Sumitomo 3M Limited), which is a vinyl chloride resin sheet.

  At this time, every time a solid image was printed for 20 minutes, the nozzle surface of the head was wiped and cleaned with a sponge roller containing the adjusted first cleaning liquid.

  Further, after printing a solid image for 8 hours a day for 2 weeks, the cloth containing the adjusted second cleaning solution was lightly pressed against the nozzle surface of the head for about 30 minutes, and then wiped off. And washed.

Evaluation of ejection stability is as follows. After the printer has been operated for 2 weeks and the ejection port is washed with the second cleaning liquid, further printing is performed, and a solid image due to bent or missing nozzles from each nozzle is obtained. The discharge stability was evaluated according to the following criteria.
◎: Almost white streaks and density unevenness are not recognized in solid images ○: Slight density unevenness is seen in solid images △: Slight white streaks and density unevenness are seen in solid images ×: Solid images Obviously white streaks and uneven density are observed

<Evaluation method of ejection stability 2>
Furthermore, evaluation no. 4 to 6, immediately after wiping the nozzle surface of the head with a sponge roller containing the first cleaning liquid every time printing is performed for 20 minutes when a solid image is printed in the same manner as in the evaluation method for ejection stability 1. Further, cleaning was performed under the condition of further wiping with a sponge roller containing the cleaning liquid 2.

The evaluation of the ejection stability includes the cleaning liquid 2 immediately after wiping the nozzle surface of the head with a sponge roller containing the first cleaning liquid after operating the printer for 2 weeks in the same manner as the evaluation method of the ejection stability 1. After washing under the condition of further wiping with a sponge roller, further printing was performed, and the uniformity of the solid image due to nozzle bending or nozzle missing from each nozzle was visually observed, and ejection stability was evaluated according to the following criteria . In the ejection stability evaluation method 2, the frequency of cleaning using the first cleaning liquid is the same as that in the ejection stability evaluation method 1.
◎: Almost white streaks and density unevenness are not recognized in solid images ○: Slight density unevenness is seen in solid images △: Slight white streaks and density unevenness are seen in solid images ×: Solid images Obviously white streaks and uneven density are observed

  The results are shown in Table 2.

<Ink solubility evaluation method>
0.05 g of the cyan ink C-1 prepared above was dropped onto a water-repellent film made of a siloxane graft polymer, which is the same material used for the nozzle surface of the head, so that the ink weight was reduced to 30% at the time of dropping. Dried until

  0.5 g of the first cleaning liquid is added to the dried ink and left for 3 minutes, and then (a) the first cleaning liquid is dropped without rubbing, or (b) the first cleaning liquid is clothed. The first cleaning liquid was removed by the two methods of wiping with.

Next, each water-repellent film from which the first cleaning liquid has been removed by the above (a) or (b) is wiped with a cloth soaked with the second cleaning liquid, and then the water-repellent film is wiped. The ink residue was visually observed and ink solubility was evaluated according to the following criteria.
5: Even if the first cleaning solution is removed without rubbing, no ink remains on the water repellent film. 4: If the first cleaning solution is removed without rubbing, a slight ink trace remains on the water repellent film. When the method of wiping off does not remain at all 3: When the method of wiping the first cleaning liquid with a cloth, no ink remains on the water repellent film 2: Even when the method of wiping the first cleaning liquid with a cloth is used, some ink remains on the water repellent film 1: Even with the method of wiping off the first cleaning liquid, a considerable amount of ink remains on the water-repellent film.

  The results are shown in Table 2.

<Evaluation method of detergency 1>
The first cleaning liquid was supplied into the ink flow path of the printer filled with ink, and the ink flow path of the printer was replaced with the first cleaning liquid for cleaning.

  Next, the second cleaning liquid was similarly supplied into the ink flow path, and the first cleaning liquid was replaced with the second cleaning liquid and left for 1 hour.

  Thereafter, the ink flow path of the printer was further replaced in the order of the second cleaning liquid, water, and then ink.

  Thereafter, the printer was operated again when the ink flow path was filled with ink.

Immediately after ink filling, image recording was performed continuously for 1 hour, and the occurrence of dot omission and ejection bending in the image was confirmed, and the cleaning performance was evaluated according to the following criteria.
5: For cleaning, missing or ejected dots were less than 10 times. 4: For missing, missing or ejected dots were 10 times or more and less than 20 times. Missing or ejected curve was 20 times or more and less than 30 times 2: For cleaning, dot missing or ejected curve was 30 times or more and less than 40 times 1: Dot missing or ejected curve was for cleaning Was over 40 times

  The results are shown in Table 2.

<Evaluation method of detergency 2>
The ink was opened for 1 hour with ink adhering to the cap of the inkjet head.

Thereafter, the cap was filled with the first cleaning liquid and left for 10 minutes to discharge, and the cap was further filled with the second cleaning liquid and left for 5 minutes before being discharged. This operation was repeated several times, and the adhesion of the ink in the cap was visually observed, and the detergency was evaluated according to the following criteria.
5: No ink remaining in the cap after one operation 4: A small amount of ink remains in the cap after one 4: 1 operation, but no ink remaining in the second operation 3: Ink in the cap after the third operation 2: No ink remains in the cap after the fourth operation 1: Ink remains in the cap even if operated more than 5 times

  The results are shown in Table 2.

<Evaluation>
From the results in Table 2, the evaluation No. 2 in which the second cleaning liquid contains water and a water-soluble organic solvent is used. Nos. 1 to 8 were evaluated No. 2 in which the second cleaning liquid did not contain water and a water-soluble organic solvent, or the second cleaning liquid was not used. Compared with 9-14, it turns out that it is excellent in discharge stability, ink solubility, and washability.

  In addition, evaluation No. 1 in which the first cleaning liquid contains a basic compound. Nos. 2 to 8 were evaluated No. 1 in which the first cleaning liquid was only water. It can be seen that the ink solubility is further improved as compared with 1.

  Furthermore, evaluation No. 1 in which the 1st washing | cleaning liquid contains amines as a basic compound. From 4 to 9, it can be seen that both ink solubility and cleanability are further improved.

  Furthermore, evaluation No. 2 in which the addition amount of the water-soluble organic solvent in the second cleaning liquid is 50% by mass or more. 8 shows that the cleaning property is further improved.

  In addition, evaluation No. 2 in which the second cleaning liquid is only a water-soluble organic solvent (water content less than 5% by mass). No. 14 indicates that the ink solubility and cleaning properties are poor.

  Further, when the frequency of cleaning using the second cleaning liquid is less than the frequency of cleaning using the first cleaning liquid (discharge stability 1), the cleaning using the first cleaning liquid and the second cleaning liquid It can be seen that the discharge stability is superior to that in the case where the frequency of cleaning using is the same (discharge stability 2).

(Example 2)
<Synthesis of binder resin>
-Preparation of polymer particles B A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen introduction tube was charged with 200 ml of distilled water and 0.6 part of sodium dodecylbenzenesulfonate in a nitrogen atmosphere. The mixture was heated to 70 ° C. with stirring, and 2 g of potassium persulfate was further added. On the other hand, 22 parts of styrene, 40 parts of methyl acrylate, 20 parts of ethyl acrylate, 10 parts of n-butyl acrylate, and 8 parts of methacrylic acid were mixed and dissolved, and this was dropped into the flask from a dropping funnel. Furthermore, after reacting at 70 ° C. for 6 hours, the solution is cooled to room temperature, a sodium hydroxide aqueous solution is added as a neutralizing agent, the pH is adjusted and filtered through a filter, and distilled water is added so that the solid content becomes 40% by mass. To obtain polymer particles B.
The acid value of the obtained polymer particles B was 50 mgKOH / g as measured by potentiometric titration. The Tg of polymer particle B was determined by DSC and found to be 15 ° C.

-Preparation of water-soluble resin A 186 parts of 2-propanol was placed in a flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen introduction tube, and heated and refluxed in a nitrogen atmosphere. A monomer solution in which 0.5 part of initiator (AIBN) was dissolved in a mixed solution of 32 parts of methyl methacrylate, 5 parts of 2-ethylhexyl acrylate, 10 parts of n-butyl acrylate, 15 parts of ethyl acrylate and 38 parts of methacrylic acid. It dropped over 2 hours from the dropping funnel. After the dropwise addition, the mixture was further heated and refluxed for 5 hours, then allowed to cool, and 2-propanol was distilled off under reduced pressure. A sodium hydroxide aqueous solution was added thereto as a neutralizing agent, and the mixture was heated and stirred at 60 ° C. to dissolve the resin, and adjusted with distilled water so that the solid content was 20% by mass to obtain a water-soluble resin A.
When the acid value of the obtained water-soluble resin A was measured by potentiometric titration, it was 250 mgKOH / g. The Tg of water-soluble resin A was determined by DSC and found to be 50 ° C.

Preparation of water-soluble resins B-1 and B-2 186 parts of 2-propanol was placed in a flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen introduction tube, and heated in a nitrogen atmosphere. Refluxed. A monomer solution in which 0.5 part of initiator (AIBN) was dissolved in a mixed solution of 40 parts of methyl methacrylate, 10 parts of 2-ethylhexyl acrylate, 35 parts of n-butyl acrylate and 15 parts of methacrylic acid was added for 2 hours from the dropping funnel. It was dripped over. After the dropwise addition, the mixture was further heated and refluxed for 5 hours, then allowed to cool, and 2-propanol was distilled off under reduced pressure. A sodium hydroxide aqueous solution was added thereto as a neutralizing agent, the mixture was heated and stirred at 60 ° C. to dissolve the resin, and a water-soluble resin B-1, which was adjusted with distilled water so that the solid content was 20% by mass, An aqueous solution of N, N-dimethylaminoethanol (DMAE) is added as a neutralizing agent, and the resin is dissolved by heating and stirring at 60 ° C., and adjusted with distilled water so that the solid content is 20% by mass. It was set as Resin B-2.
The acid value of the obtained water-soluble resins B-1 and B-2 was 100 mgKOH / g as measured by potentiometric titration. Moreover, it was 15 degreeC when Tg of water-soluble resin A was calculated | required by DSC.

<Preparation of ink>
Inks C-2 to C-9 were prepared as shown below.

-Preparation of ink C-2 As a water-soluble organic solvent, 10 parts by mass of 1,2-hexanediol (HDO) and 10 parts by mass of propylene glycol (PG) were added to 20 parts by mass of ion-exchanged water. An aqueous solvent was obtained.
10.9 parts by mass of polymer particles A (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., acrylic resin, solid content 46% by mass, acid value: 0 mgKOH / g, Tg: 0 ° C.) as a binder resin are added to the obtained aqueous solvent. The whole amount was adjusted to 79 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 1 part by mass of KF-351A as a surfactant were added and stirred.
The obtained solution was filtered with a 0.8 μm filter to obtain cyan ink C-2.

-Preparation of ink C-3 As a water-soluble organic solvent, 10 parts by mass of 1,2-hexanediol (HDO), 5 parts by mass of 2-pyrrolidone (2PDN), 1,3-dimethyl-2-imidazolide 5 parts by mass of non (DMI) and 20 parts by mass of ion-exchanged water were added to obtain an aqueous solvent.
To the obtained aqueous solvent, 12.5 parts by mass of the polymer particle B prepared as a binder resin was added and stirred, and the total amount was 79 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 1.00 part by mass of e1010 as a surfactant were added and stirred.
The obtained solution was filtered with a 0.8 μm filter to obtain cyan ink C-3.

-Preparation of ink C-4 As a water-soluble organic solvent, 10 parts by mass of 1,2-hexanediol (HDO), 5 parts by mass of 2-pyrrolidone (2PDN), 1,3-dimethyl-2-imidazolide 5 parts by mass of non (DMI) and 20 parts by mass of ion-exchanged water were added to obtain an aqueous solvent.
To the obtained aqueous solvent, 30 parts by mass of water-soluble resin A as a binder resin was added and stirred, and the total amount was 79 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 1.00 part by mass of e1010 as a surfactant were added and stirred.
The obtained solution was filtered with a 0.8 μm filter to obtain cyan ink C-4.

-Preparation of ink C-5 As a water-soluble organic solvent, 5 parts by mass of dipropylene glycol propyl ether (DPGPE), 5 parts by mass of dipropylene glycol methyl ether (DPGME), and 5 parts by mass of sulfolane were ionized. It added to 20 mass parts of exchange water, and obtained the aqueous solvent.
To the obtained aqueous solvent, 25 parts by mass of water-soluble resin B-1 as a binder resin was added and stirred, and the total amount was adjusted to 80 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 0.02 parts by mass of MF477 as a surfactant were added and stirred.
The obtained solution was filtered through a 0.8 μm filter to obtain cyan ink C-5.

-Preparation of ink C-6 As a water-soluble organic solvent, 5 parts by mass of 1,2-hexanediol (HDO), 10 parts by mass of dipropylene glycol methyl ether (DPGME), and 5 parts by mass of sulfolane It added to 20 mass parts of ion exchange water, and obtained the aqueous solvent.
To the obtained aqueous solvent, 30 parts by mass of water-soluble resin B-2 as a binder resin was added and stirred, and the total amount was adjusted to 80 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 0.02 parts by mass of MF477 as a surfactant were added and stirred.
The obtained solution was filtered through a 0.8 μm filter to obtain cyan ink C-6.

-Preparation of Ink C-7 As a water-soluble organic solvent, 5 parts by mass of 1,2-hexanediol (HDO), 10 parts by mass of dipropylene glycol methyl ether (DPGME), and the aforementioned β-alkoxypropionamides In general formula (I), R ₁ , R _2, and R ₃ are all methyl groups, β-alkoxypropionamide (solvent A-1) is added to 5 parts by mass, and ion-exchanged water is added to 20 parts by mass, An aqueous solvent was obtained.
To the obtained aqueous solvent, 25 parts by mass of water-soluble resin B-2 as a binder resin was added and stirred, and the total amount was adjusted to 80 parts by mass with ion-exchanged water.
To the obtained solution, 20 parts by mass of the cyan pigment dispersion prepared in Example 1 and 0.02 parts by mass of MF477 as a surfactant were added and stirred.
The resulting solution was filtered through a 0.8 μm filter to obtain cyan ink C-7.

-Preparation of Ink C-8 As a water-soluble organic solvent, 5 parts by mass of 1,2-hexanediol (HDO), 10 parts by mass of dipropylene glycol methyl ether (DPGME), and the aforementioned β-alkoxypropionamides In general formula (I), R ₁ and R ₂ are methyl groups, and R ₃ is an n-butyl group β-alkoxypropionamide (solvent A-2), 5 parts by mass, and ion-exchanged water 20 parts by mass To obtain an aqueous solvent.
To the obtained aqueous solvent, 25 parts by mass of water-soluble resin B-2 as a binder resin was added and stirred, and the total amount was adjusted to 80 parts by mass with ion-exchanged water.
20 parts by mass of the cyan pigment dispersion prepared in Example 1 was added to the obtained solution and stirred.
The obtained solution was filtered through a 0.8 μm filter to obtain cyan ink C-8.

-Preparation of ink C-9 Cyan ink C-9 was obtained in the same manner as C-8, except that no binder resin was added to ink C-8.

  Table 3 shows the compositions of the inks C-2 to C-9 prepared above. In the above description relating to the preparation of the ink, the amount of resin added indicates the amount of the resin solution to be actually added, but the amount of resin added in Table 3 indicates the added active ingredient (resin only). Is shown.

<Evaluation method of ejection stability 3>
In Example 1, instead of the cyan ink C-1, the inks C-2 to C-9 prepared above were used, the cleaning liquid g was used as the first cleaning liquid, and the cleaning liquid e was used as the second cleaning liquid. The same discharge stability was evaluated.

  The results are shown in Table 4.

<Rubbing resistance evaluation method>
A solid image of each ink was prepared, and the image after the image was rubbed with dry cotton (Kanakin No. 3) under a weight of 500 g was visually observed, and the rub resistance was evaluated according to the following criteria.
◎: Image does not change even after rubbing 50 times or more ○: Some scratches remain after rubbing 30-50 times, but does not affect image density Δ: Image density slightly decreases after rubbing 5-30 times X: Image density decreases during rubbing 4 times or less

  The results are shown in Table 4.

<Glossy evaluation method>
In the same manner as the evaluation method for the abrasion resistance, a solid image of each ink was prepared, and the glossiness of the solid image portion was visually observed and evaluated according to the following criteria.
A: There is no gloss difference between the printed part and the non-printed part, and the glossiness is excellent. ○: There is a slight difference in gloss between the printed part and the non-printed part, but there is no problem in image quality. Gloss difference from the printed part can be recognized, and the image quality is not acceptable. ×: The difference in gloss between the printed part and the unprinted part is large, and the image quality is significantly deteriorated.

  The results are shown in Table 4.

<Evaluation>
From the results of Table 4, when the ink C-2, which is a water-insoluble resin having no acidic group as the binder resin, is used, the injection stability, scratch resistance and gloss are in a range where there is no practical problem. It was a little inferior.

  It can be seen that when ink C-3 containing a water-insoluble resin having an acidic group as the binder resin is used, the injection stability and the abrasion resistance are improved.

  Furthermore, it can be seen that in the case of inks C-4 to C-8 in which the binder resin contains a water-soluble resin having an acidic group, the injection stability is further improved.

  Furthermore, it can be seen that in the case of the inks C-6 to C-8 in which the acidic group of the binder resin is neutralized with a neutralizing base of amines, the abrasion resistance is further improved.

  Furthermore, it can be seen that when the inks are inks C-7 and C-8 containing β-alkoxypropionamide, the injection stability, abrasion resistance and gloss are further improved.

  On the other hand, when ink C-9 containing no binder resin was used, it was found that the abrasion resistance and gloss were remarkably inferior.

1: Inkjet head 11: Ejection port forming surface 21: Blade-shaped absorbent member 22: Roller-shaped absorbent member 23: Sheet-shaped absorbent member

Claims (25)

Inkjet recording apparatus cleaning liquid for cleaning an ink ejection port in an inkjet recording apparatus that ejects aqueous ink containing at least a binder resin to form an image on a recording medium or a portion that affects ink ejection in the vicinity of the ink ejection port A set,
A first cleaning liquid containing a component that lowers the viscosity of the water-based ink;
A second cleaning liquid different from the first cleaning liquid, including water and a water-soluble organic solvent that dissolves the water-based ink solidified at a site that affects ink ejection in the vicinity of the ink ejection port or the ink ejection port;
A cleaning liquid set for an ink jet recording apparatus, comprising:   The cleaning liquid set for an ink jet recording apparatus according to claim 1, wherein the binder resin of the water-based ink is a water-soluble resin having at least an acidic group.   The cleaning liquid set for an ink jet recording apparatus according to claim 2, wherein the water-soluble resin is an acrylic resin having an acid value in the range of 50 mgKOH / g to 200 mgKOH / g.   4. The cleaning liquid set for an ink jet recording apparatus according to claim 2, wherein the water-soluble resin is partially or completely neutralized with an amine compound. The cleaning liquid set for an ink jet recording apparatus according to claim 1, wherein the water-based ink contains β-alkoxypropionamides represented by the following general formula (1).

[Wherein, R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, R ₂ and R ₃ represent a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms; ₂ and R ₃ may be the same or different. ]   The cleaning liquid set for an ink jet recording apparatus according to claim 1, wherein the first cleaning liquid contains water and a basic compound.   The cleaning liquid set for an ink jet recording apparatus according to claim 6, wherein the basic compound is an amine compound.   8. The cleaning liquid set for an ink jet recording apparatus according to claim 1, wherein the water-soluble organic solvent contained in the second cleaning liquid has a solubility parameter (SP value) in the range of 8 or more and 10 or less. .   9. The cleaning liquid set for an ink jet recording apparatus according to claim 8, wherein the water-soluble organic solvent is an alkylene glycol alkyl ether.   10. The cleaning liquid set for an ink jet recording apparatus according to claim 9, wherein the alkylene glycol alkyl ether is contained in the second cleaning liquid in an amount of 50% by mass or more.   The cleaning liquid set for an ink jet recording apparatus according to claim 1, wherein the second cleaning liquid contains water in a range of 5 mass% or more. An aqueous ink containing at least a binder resin;
Inkjet comprising a cleaning liquid set for an inkjet recording apparatus for cleaning an ink ejection port of an inkjet recording apparatus that ejects the water-based ink to form an image on a recording medium or a portion that affects ink ejection in the vicinity of the ink ejection port An ink set for a recording apparatus,
The cleaning liquid for the ink jet recording apparatus dissolves the first cleaning liquid containing a component that lowers the viscosity of the water-based ink and the water-based ink solidified at the ink discharge port or a portion that affects ink discharge near the ink discharge port. An ink set for an ink jet recording apparatus, comprising: a second cleaning liquid different from the first cleaning liquid.   The ink set for an ink jet recording apparatus according to claim 12, wherein the binder resin of the water-based ink is a water-soluble resin having at least an acidic group.   The ink set for an ink jet recording apparatus according to claim 13, wherein the water-soluble resin is an acrylic resin having an acid value in the range of 50 mgKOH / g to 200 mgKOH / g.   The ink set for an inkjet recording apparatus according to claim 13 or 14, wherein the water-soluble resin is partially or completely neutralized with an amine compound. The ink set for an ink jet recording apparatus according to any one of claims 12 to 15, wherein the water-based ink contains β-alkoxypropionamides represented by the following general formula (1).

[Wherein, R ₁ represents a linear or branched alkyl group having 1 to 6 carbon atoms, R ₂ and R ₃ represent a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms; ₂ and R ₃ may be the same or different. ]   The ink set for an ink jet recording apparatus according to claim 12, wherein the first cleaning liquid contains water and a basic compound.   The ink set for an ink jet recording apparatus according to claim 17, wherein the basic compound is an amine compound.   The ink set for an ink jet recording apparatus according to any one of claims 12 to 18, wherein the water-based ink contains a surfactant, and the first cleaning liquid does not contain a surfactant.   The ink set for an ink jet recording apparatus according to any one of claims 12 to 19, wherein the water-soluble organic solvent contained in the second cleaning liquid has a solubility parameter (SP value) in the range of 8 to 10. .   21. The ink set for an inkjet recording apparatus according to claim 20, wherein the water-soluble organic solvent is an alkylene glycol alkyl ether.   The ink set for an ink jet recording apparatus according to claim 21, wherein the alkylene glycol alkyl ether is contained in the second cleaning liquid in an amount of 50 mass% or more.   The ink set for an ink jet recording apparatus according to any one of claims 12 to 22, wherein the second cleaning liquid contains water in a range of 5 mass% or more. An ink jet recording apparatus cleaning method using the ink set for an ink jet recording apparatus according to any one of claims 12 to 23,
A first cleaning step for performing cleaning to reduce the viscosity of the water-based ink adhering to the ink discharge port or a portion that affects ink discharge in the vicinity of the ink discharge port by the absorbing member impregnated with the first cleaning liquid;
Cleaning that dissolves the water-based ink solidified at an ink discharge port or a portion that affects ink discharge near the ink discharge port by an absorbing member impregnated with the second cleaning liquid at a timing different from that of the first cleaning step. And a second cleaning step for performing an ink jet recording apparatus cleaning method. The first cleaning step is performed at relatively short intervals;
25. The method of cleaning an ink jet recording apparatus according to claim 24, wherein the second cleaning step is performed at a relatively medium to long term interval.

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