JP4752097B2 - Cleaning solution for inkjet printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet printer cleaning liquid, and more particularly to an inkjet printer cleaning liquid using a water-dispersible resin or an aqueous ink containing water-dispersible colored particles.
[0002]
[Prior art]
As a cleaning liquid for an ink jet printer, JP-A-58-71170 exemplifies that a liquid obtained by removing a dye from a dye ink is used as a cleaning liquid. JP-A-62-169876 discloses a maintenance liquid composed of polyhydric alcohols, monohydric alcohols and water, and JP-A-62-1169877 discloses a maintenance liquid composed of a lower alcohol, an anionic surfactant and water. JP-A-01-148557 proposes an aqueous maintenance liquid for an ink jet printer comprising a water-soluble chelating agent.
[0003]
[Problems to be solved by the invention]
The maintenance liquid is effective for cleaning and maintenance of an ink jet printer using a completely dissolved ink in which an aqueous dye is dissolved. An aqueous ink containing a water-dispersible resin such as an emulsion in addition to a colorant Water-based pigment inks in which pigments are dispersed with a dispersant, microcapsule inks in which pigments are coated with a water-dispersible resin, etc., are likely to cause water insoluble matter to adhere to the nozzles of the print head. In many cases, nozzle cleaning is required.
[0004]
The problem to be solved by the present invention is to provide a cleaning liquid for an ink jet printer that can easily recover from a nozzle clogging failure due to an excellent cleaning effect. In particular, an object of the present invention is to provide a cleaning liquid having an excellent cleaning effect for an inkjet printer using an aqueous resin containing an emulsion resin, a pigment, a microcapsule pigment coated with a resin, and the like.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a cleaning liquid for an ink jet printer that contains at least a water-soluble salt of hydroxycarboxylic acid, limonene, and a surfactant.
[0006]
Hydroxycarboxylates are generally known to have a chelating effect, particularly effective for cleaning metals. Among them, the hydroxycarboxylic acid is preferably citric acid or gluconic acid, and their water-soluble salts with alkali metals (lithium, potassium, sodium) are suitable for a wide range of head materials such as glass, ceramics, and plastics as well as metals. Shows a strong cleaning effect without corrosion.
[0007]
Limonene is a substance that is abundant in citrus fruits such as oranges and has excellent ability to dissolve fats and oils, but itself behaves as an organic solvent insoluble in water. By containing a surfactant as the third component, limonene can be dissolved in the cleaning liquid, and in addition to the cleaning effect of the hydroxycarboxylate and limonene, the cleaning performance of the cleaning liquid can be increased synergistically.
[0008]
A preferred type of the surfactant of the present invention is a nonionic or anionic surfactant, and known and commonly used surfactants can be used. Specific examples include those listed below, but are not limited thereto. Absent.
[0009]
Nonionic surfactants include sorbitan fatty acid ester, glycerin fatty acid ester, decagrin fatty acid ester, polyglycerin fatty acid ester, propylene glycol / pentaerythritol fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin. Fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene / polyoxypropylene block polymer, polyoxyethylene alkylphenyl ether, acetylene glycol, polyoxyethylene castor oil / cured Castor oil, polyoxyethylene lanolin / lanolin alcohol, Polyoxyethylene alkyl amine fatty acid amides, polyoxyethylene alkylphenyl formaldehyde condensates, there is a fluorine-based surface active agents such as polyoxyethylene perfluoroalkyl.
[0010]
Anionic surfactants include alkyl sulfates, polyoxyethylene alkyl sulfates, N-acyl amino acids and their salts, N-acyl methyl taurates, dialkyl sulfosuccinates, disodium sulfosuccinate monoesters, N-alkyl sulfosuccinates. Examples include acid monoamides, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α-olefin sulfonates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and the like.
[0011]
Among the surfactants, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, and polyoxyethylene / polyoxypropylene / block polymer, which are generally called nonionic polyoxyalkylene alkyl ethers, are preferable in terms of effects.
[0012]
The total content of the water-soluble salt of hydroxycarboxylic acid, limonene, and surfactant in the cleaning liquid as the cleaning agent component is preferably in the range of 0.01 to 10% by weight, particularly in the range of 0.05 to 5.0% by weight. Is preferable because the viscosity of the cleaning agent is low, the fluidity in the nozzle is good, and the cleaning effect is high.
[0013]
As other additives, anti-drying agents used in inkjet water-based inks, antiseptics, water-soluble organic solvents such as inorganic alkalis, alcohol amines, and lower alcohols can be added as necessary.
[0014]
The ink combined with the cleaning agent of the present invention is effective even with a dye ink, but particularly exhibits a cleaning effect with an aqueous inkjet ink such as an emulsion resin-containing ink or a pigment ink containing water-dispersible colored particles.
[0015]
Examples of pigment ink pigments include inorganic pigments such as carbon black, titanium black, titanium white, zinc sulfide, and bengara; azo pigments such as phthalocyanine pigments, monoazo and disazo pigments, and organic pigments such as phthalocyanine pigments and quinacridone pigments. .
[0016]
The pigment can be used as a microcapsule pigment dispersed with a known dispersant or coated with a film-forming resin.
[0017]
With respect to such a pigment, the cleaning agent of the present invention exhibits a certain cleaning effect. The emulsion resin, dispersant, and film-forming resin used in the ink to be cleaned so that the present invention is effective include general acrylic resins, polyester resins, epoxy resins, maleic resins having acid values. Although not particularly limited, such as acid resin, styrene- (meth) acrylic acid resin, for example, substituted styrene such as styrene or α-methylstyrene, methyl acrylate, ethyl acrylate, butyl acrylate At least one monomer unit selected from acrylic acid esters such as 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; Acry Acid, exhibits a particularly remarkable cleaning effect on the copolymer containing at least one monomer unit selected from methacrylic acid.
[0018]
Ink-jet recording inks containing water-dispersible colored particles such as water-dispersible resins and pigments, or pigments coated with a film-forming resin, use a water-soluble organic solvent for preventing drying as a drying inhibitor. In general, it is used in combination, and as such a drying inhibitor, it has an effect of preventing the ink from drying at the jet nozzle opening of the inkjet, and a polyhydric alcohol such as ethylene glycol, diethylene glycol, polyethylene glycol, or glycerin. Pyrrolidones such as N-methyl-2-pyrrolidone and 2-pyrrolidone; amides; dimethylsulfoxide, imidazolidinone and the like having a boiling point higher than that of water are used, but particularly for the colored particles. If the glass transition temperature of the resin is low, nozzle clogging is likely to occur. Cleaning liquid is effective.
[0019]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following examples, “part” represents “part by mass” unless otherwise specified.
[0020]
Example 1
<Example of cleaning solution>
0.1 part of potassium citrate, 0.2 part of potassium gluconate, 0.3 part of polyoxyethylene (10) dodecyl ether, 0.3 part of polyoxyethylene (20) lauryl ether, polyoxyethylene (1) / poly Oxypropylene (8) cetyl ether 0.2 part, limonene 0.2 part, ethanol 0.1 part, preservative 0.1 part is dissolved in 98.6 parts of pure water, filtered through a 0.5 μm filter and washed. It was.
[0021]
<Ink example>
Using two rolls, 20 parts of carbon black and 20 parts of styrene-acrylic acid-methacrylic acid resin (styrene / acrylic acid / methacrylic acid = 77/10/13; molecular weight 50,000, acid value 160, glass transition temperature 107 ° C.) The kneaded product was put into a mixed solution consisting of 210 parts of water, 35 parts of glycerin, 8 parts of triethanolamine, 90 parts of methyl ethyl ketone and 40 parts of isopropyl alcohol, and stirred at room temperature for 3 hours to obtain a colorant suspension. It was. While stirring the obtained suspension, a mixed liquid of 30 parts of glycerin and 210 parts of water was dropped at a rate of 5 ml per minute to obtain a black colored resin particle aqueous dispersion. Methyl ethyl ketone, isopropyl alcohol and a part of water were distilled off from the obtained capsule liquid using a rotary evaporator to obtain an aqueous dispersion of black colored resin particles having a pigment content of 14% by weight.
[0022]
25 parts of the colored resin particle aqueous dispersion is added to 10 parts of diethylene glycol, 5 parts of propylene glycol propyl ether, and 0.5 part of an emulsion resin (PDX-7111B; manufactured by Johnson Polymer) is added to 59.5 parts of pure water and mixed. Then, filtration was performed using a 0.5 μm membrane filter to obtain an aqueous ink for inkjet recording.
[0023]
The obtained water-based ink was printed using a piezo-type ink jet printer (MJ-8000C manufactured by Seiko Epson Corporation) and showed strong adhesion to the recording medium. The nozzle of the part was clogged. As a result of cleaning using the cleaning liquid of the cleaning liquid example, the nozzle deposits were easily removed and stable injection became possible.
[0024]
(Comparative Example 1)
In the example of the cleaning liquid of Example 1, the surfactant was removed, but the limonene oil phase was formed on the aqueous phase, and the cleaning liquid was not obtained.
[0025]
(Comparative Example 2)
In the example of the cleaning liquid of Example 1, it was blended except for limonene to obtain a cleaning liquid in the same manner.
As a result of cleaning the clogged nozzle with the cleaning liquid in the same manner as in Example 1, the nozzle deposits were not completely removed, and the ink ejection direction was not stable.
[0026]
(Comparative Example 3)
In the example of the cleaning liquid of Example 1, the mixture was mixed except for potassium citrate and potassium gluconate to obtain a cleaning liquid. As a result of cleaning the clogged nozzle with the cleaning liquid in the same manner as in Example 1, the nozzle deposits were not completely removed, and the ink ejection direction was not stable.
[0027]
【The invention's effect】
The cleaning liquid of the present invention can easily recover from nozzle clogging failure due to an excellent cleaning effect for an inkjet printer using an emulsion resin, a pigment, and an aqueous ink containing a microcapsule pigment coated with a resin. It becomes possible.

Claims (4)

  A cleaning liquid for an ink jet printer, comprising at least a water-soluble salt of hydroxycarboxylic acid and limonene and a surfactant.   2. The cleaning liquid for an ink jet printer according to claim 1, wherein the hydroxycarboxylic acid is citric acid or gluconic acid. The cleaning liquid for an inkjet printer according to claim 1 or 2, wherein the surfactant is a nonionic or anionic surfactant.   The cleaning liquid for an ink jet printer according to claim 3, wherein the nonionic surfactant is a polyoxyalkylene alkyl ether.