JP2018069453A - Cleaning liquid, set of ink and cleaning liquid, cleaning method, storage container and ink discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide cleaning liquid that permeates a little into a nozzle hole in wiping a nozzle face of an ink discharge head with a wiping member and can maintain cleanliness of the nozzle face.SOLUTION: Cleaning liquid is used in wiping a nozzle face 301a of an ink discharge head in an ink discharge device with a wiping member 303. The cleaning liquid has static surface tension that is higher than static surface tension of ink. The cleaning liquid has a contact angle of 20° or more and 35° or less relative to a dried ink film.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cleaning liquid, a set of ink and cleaning liquid, a cleaning method, a container, and an ink ejection device.

  2. Description of the Related Art Conventionally, as a recording apparatus such as a printer, a facsimile machine, a copying apparatus, a plotter, or a complex machine thereof, for example, an ink ejection type recording apparatus having an ink ejection head is known.

In recent years, pigment ink has been increasingly used as an ink used in the ink discharge type recording apparatus because of its excellent water resistance and light resistance.
Inkjet recording using the pigment ink has been used for commercial printing applications such as a high-speed continuous book machine. In such commercial printing applications, it is required to obtain the same image quality as that of offset printing even for printing coated paper with low ink absorption as a recording medium. Has been made. For this reason, it is considerably difficult to ensure ink ejection reliability. In particular, highly fixable ink tends to adhere to the nozzle surface and the like, and it is difficult to remove the adhered ink cleanly by wiping the nozzle surface using a conventional rubber blade or the like.

  Thus, for example, an ink set for inkjet recording has been proposed that includes an ink composition containing water, a pigment, and polymer particles and a maintenance liquid containing propylene glycol monopropyl ether (see, for example, Patent Document 1).

  An object of the present invention is to provide a cleaning liquid that has little penetration into nozzle holes when the nozzle surface of an ink discharge head is wiped with a wiping member and can maintain the cleanliness of the nozzle surface.

The cleaning liquid of the present invention as a means for solving the problems is a cleaning liquid used when wiping the nozzle surface of the ink discharge head in the ink discharge apparatus with a wiping member,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
The contact angle of the cleaning liquid with respect to the film obtained by drying the ink is 20 ° or more and 35 ° or less.

  According to the present invention, it is possible to provide a cleaning liquid that has little penetration into the nozzle hole when the nozzle surface of the ink discharge head is wiped with the wiping member and can maintain the cleanliness of the nozzle surface.

FIG. 1 is a perspective explanatory view showing an example of a serial type image forming apparatus. FIG. 2 is a perspective explanatory view showing an example of a main tank of the apparatus of FIG. FIG. 3 is a schematic view showing an example of the cleaning apparatus of the present invention.

(Cleaning solution)
The cleaning liquid of the present invention is a cleaning liquid used when wiping the nozzle surface of the ink discharge head in the ink discharge apparatus with a wiping member,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
The contact angle of the cleaning liquid with respect to the film from which the ink has been dried is 20 ° to 35 °, and preferably contains water, an alkylene glycol surfactant, and a glycol ether compound, and other components as necessary. Containing.

In the cleaning liquid of the present invention, in the conventional method of wiping the nozzle surface of the ink discharge head with a blade, the cleaning liquid is used in the nozzle hole when the static surface tension of the cleaning liquid used for wiping is lower than the static surface tension of the ink. This is based on the knowledge that the image density decreases and the printing after cleaning is adversely affected.
In addition, the cleaning liquid of the present invention is mainly used to prevent corrosion of the ink discharge head due to a decrease in pH and to prevent aggregation when mixed with ink in the conventional cleaning liquid, and when a highly fixable ink is used. This is based on the knowledge that the cleanliness of the nozzle surface of the ink discharge head cannot be maintained.

In the present invention, the nozzle surface is adjusted by the wiping member by adjusting the static surface tension of the cleaning liquid used for cleaning the nozzle surface in the ink discharge head to be higher than the static surface tension of the ink used together. When wiping, it is possible to prevent the cleaning liquid from penetrating into the nozzle hole from the wiping member. When the cleaning liquid penetrates into the nozzle hole from the wiping member, the image density after cleaning is lowered.
The static surface tension of the cleaning liquid is preferably 26.0 mN / m or less and 35.0 mN / m or less at 25 ° C.
The static surface tension of the ink is preferably 20.0 mN / m or less and 30.0 mN / m or less at 25 ° C.
The static surface tension of the cleaning liquid is preferably 2.0 mN / m or more higher than the static surface tension of the ink.
The static surface tension of the ink and the cleaning liquid can be measured under an environment of 25 ° C. using, for example, an automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Co., Ltd.

The cleaning liquid is preferably wetted to some extent by the dried ink film in order to wipe away the ink that has dried and adhered to the nozzle surface. If the wettability is good, it is possible to cope with a relatively wide range of ink fixation even with a small amount of cleaning liquid, but if it is too wide, penetration into the ink fixation is limited. Therefore, the contact angle of the cleaning liquid with respect to the dried ink film is 20 ° to 35 °, and preferably 20 ° to 27 °.
When the contact angle of the cleaning liquid with respect to the film obtained by drying the ink is 20 ° or more and 35 ° or less, the cleanliness by wiping the nozzle surface can be improved.
Here, the contact angle of the cleaning liquid with respect to the film obtained by drying the ink can be measured, for example, as follows.
On the slide glass, ink is applied with a wire bar having a diameter of 0.3 mm and dried with a dryer at 50 ° C. for 24 hours to form an ink film.
Next, using a contact angle meter OCA-200H manufactured by Eihiro Seiki Co., Ltd., 5 μL of the cleaning liquid is dropped on the ink film, and the contact angle 0.5 seconds after the landing can be calculated from the video. .

<Alkylene glycol surfactant>
It is necessary to adjust the static surface tension of the cleaning liquid to be higher than the static surface tension of the ink used together. As a method for adjusting the static surface tension, the kind of the surfactant to be used may be changed, or may be adjusted by changing the addition amount of the surfactant. It is also possible to formulate in consideration of the surface tension of the solvent used together.
Since recent inks are required to have high quick drying properties, surfactants having a high ability to reduce surface tension such as fluorine surfactants and silicone surfactants are usually added. For the purpose of cleaning the ink flow path and the like, the surface tension of the cleaning liquid needs to be higher than the surface tension of the ink. Fluorine surfactants and silicone surfactants are often used for the cleaning liquid, but in the cleaning liquid used for wiping the nozzle surface, an alkylene glycol surfactant is used in consideration of penetration into the nozzle holes. It is preferable to use it.
The alkylene glycol surfactant is, for example, a glycol surfactant containing an alkylene group such as an ethylene oxide group or a propylene oxide group.
As said alkylene glycol surfactant, what was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include Emulgen LS-106 (manufactured by Kao Corporation), Emulgen LS-110 (manufactured by Kao Corporation), Softanol EP7025 (manufactured by Nisshin Chemical Co., Ltd.), and the like.
The content of the alkylene glycol surfactant is preferably 0.1% by mass or more and 5% by mass or less based on the total amount of the cleaning liquid.

<Glycol ether compound>
The glycol ether compound is an organic solvent contained in order to adjust the static surface tension of the cleaning liquid and the wettability to the ink film within a predetermined range.
Examples of the glycol ether compound include ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol monomethyl. Ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, propylene glycol n-propyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tripropylene Glycol monomethyl ether, tetraethylene glycol dimethyl ether, etc. tetraethylene glycol diethyl ether. These may be used individually by 1 type and may use 2 or more types together. Among these, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, and diethylene glycol methyl ethyl ether are preferable, and diethylene glycol diethyl ether is particularly preferable.
As content of the said glycol ether compound, 20 mass% or more and 50 mass% or less are preferable with respect to the washing | cleaning liquid whole quantity, and 30 mass% or more and 40 mass% or less are more preferable. If the content is 20% by mass or more, the ability to wipe off the adhered ink stains is secured. Moreover, the influence on the member used for a wiping member or a wiping process can be suppressed as the said content is 50 mass% or less.

  For the purpose of controlling the permeability to the ink film, the cleaning liquid may be used in combination with a polyol compound having 8 to 11 carbon atoms as an organic solvent, for example, 2-ethyl-1,3-hexanediol. 2,2,4-trimethyl-1,3-pentanediol and the like.

-Other organic solvents-
In this invention, in the range which does not impair the effect of this invention, you may contain another organic solvent besides the said glycol ether compound and a C8-C11 polyol compound.
There is no restriction | limiting in particular as said other organic solvent, According to the objective, it can select suitably, For example, a water-soluble organic solvent etc. are mentioned.
The water-soluble organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyhydric alcohols; ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers; Examples include nitrogen heterocyclic compounds; amides; amines; sulfur-containing compounds, propylene carbonate, ethylene carbonate, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the polyhydric alcohols include polyethylene glycol, polypropylene glycol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1 , 2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol and the like.

  Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ- Examples include butyrolactone.

  Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.

  Examples of the amines include monoethanolamine, diethanolamine, and triethylamine.

Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.
The total content of the organic solvent is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 60% by mass or less, with respect to the total amount of the cleaning liquid.

<Water>
Examples of the water include pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, or ultrapure water.
There is no restriction | limiting in particular as content of the said water, Although it can select suitably according to the objective, 20 mass% or more and 80 mass% or less are preferable with respect to the washing | cleaning liquid whole quantity, 30 mass% or more and 70 mass% or less. Is more preferable. When the content is 20% by mass or more, the ink stain can be wiped cleanly from the interface of the nozzle surface, and when it is 80% by mass or less, the stain can be sufficiently swollen.

<Other ingredients>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, an antifoamer, antiseptic / antifungal agent, a rust preventive agent, a pH adjuster etc. are mentioned.

  The cleaning liquid of the present invention is used when wiping the nozzle surface of the ink ejection head in the ink ejection apparatus, and as a method of using the cleaning liquid, it may be used by being included in a wiping member. Then, the wiping member may be wiped off.

  As the ink used together with the cleaning liquid, the following inks and inks in a cleaning liquid set are preferably used. The cleaning liquid is preferably for inkjet.

(Set of ink and cleaning liquid)
The ink and cleaning liquid set of the present invention includes an ink containing resin particles,
A cleaning solution containing an alkylene glycol surfactant,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
The contact angle of the cleaning liquid with respect to the film obtained by drying the ink is 20 ° or more and 35 ° or less.
As the cleaning liquid, the cleaning liquid of the present invention can be used.
The cleaning liquid preferably further contains a glycol ether compound.
It is preferable that content of the glycol ether compound is 20% by mass or more and 50% by mass or less.
The ink is preferably used for inkjet.
The ink described below can be used as the ink.
When the ink contains resin particles, the fixability of the ink to the recording medium is improved, but it becomes difficult to maintain the ejection reliability of the ink. Therefore, the ink is preferably used in the set with the cleaning liquid of the present invention.

<Ink>
The ink preferably contains resin particles, an organic solvent, and a coloring material, and further contains additives as necessary.

<Resin particles>
The type of resin in the resin particles contained in the ink is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene type Examples thereof include resins, butadiene resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, urethane resin is preferable.
The resin particles can be mixed with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium to obtain an ink.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm or more and 1,000 nm or less from the viewpoint of obtaining good fixability and high image hardness. It is more preferably 200 nm or less and particularly preferably 10 nm or more and 100 nm or less.
The volume average particle diameter can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

  There is no restriction | limiting in particular as content of the said resin particle, Although it can select suitably according to the objective, 1 mass% or more and 30 mass with respect to the total amount of ink from the point of fixability and the storage stability of an ink. % Or less is preferable, and 5 mass% or more and 20 mass% or less are more preferable.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -N-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples thereof include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

<Water>
The water content in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 90% by mass or less, and 20% by mass from the viewpoint of ink drying property and ejection reliability. % To 60% by mass is more preferable.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. A mixed crystal may be used.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy pigment such as gold or silver, a metallic pigment, or the like can be used.
Carbon black produced by known methods such as contact method, furnace method, thermal method in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow as inorganic pigments Can be used.
Organic pigments include azo pigments, polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments). Dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11). And metal pigments such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
Further, for color use, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used. One kind may be used alone, or two or more kinds may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

  The content of the color material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass from the viewpoints of improvement in image density, good fixability and ejection stability. It is as follows.

In order to obtain an ink by dispersing a pigment, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing, a dispersing agent is used. Method, etc.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of making it dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon) Is mentioned.
As a method for coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is included in microcapsules and dispersible in water can be mentioned. This can be paraphrased as a resin-coated pigment. In this case, it is not necessary that all pigments blended in the ink are coated with a resin, and within a range where the effects of the present invention are not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. It may be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant or high-molecular type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and naphthalenesulfonic acid Na formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
An ink can be obtained by mixing a material such as water or an organic solvent with a pigment. Further, it is also possible to produce an ink by mixing a pigment, other water, a dispersant, and the like into a pigment dispersion and mixing a material such as water or an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. For dispersion, a disperser may be used.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of maximum number because the pigment dispersion stability is good and the image quality such as ejection stability and image density is also high. 500 nm or less is preferable and 20 nm or more and 150 nm or less are more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1% by mass. % To 50% by mass is preferable, and 0.1% to 30% by mass is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

  The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of improving the image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number is converted. Is preferably 20 nm to 1000 nm, and more preferably 20 nm to 150 nm. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust inhibitor, a pH adjuster, and the like may be added to the ink.

<Surfactant>
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
There is no restriction | limiting in particular as said polyether modified silicone surfactant, According to the objective, it can select suitably, For example, the polyalkylene oxide structure represented by a general formula (S-1) type | formula is dimethylpolyethylene. Examples thereof include those introduced into the side chain of Si part of siloxane.
[General Formula (S-1)]
(However, in the formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)
A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Corporation), TSF4440, TSF4452, TSF4453 (Toshiba Silicone Corporation), etc. are mentioned.

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and in particular, fluorine-based compounds represented by the general formulas (F-1) and (F-2) A surfactant is preferred.
[General Formula (F-1)]
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
[General Formula (F-2)]
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the general formula (F-2), Y is H, or CmF _{2m + 1} , m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CmF _{2m + 1,} where m is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. n is an integer of 1-6. a is an integer of 4-14.
A commercial item may be used as said fluorosurfactant.
As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251 FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (Omnova), Unidyne DSN -403N (manufactured by Daikin Industries, Ltd.) and the like. Among these, FS manufactured by Chemours Co., Ltd. from the viewpoint that remarkably improved good print quality, particularly color developability, paper permeability, wettability, and leveling. -3100, FS-34, FS-300, Neos Co., Ltd. FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW, Polynova PF-151N made by Omninova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. is particularly preferable.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

<Antifoaming agent>
There is no restriction | limiting in particular as an antifoamer, For example, a silicone type antifoamer, a polyether type | system | group antifoamer, a fatty-acid ester type | system | group antifoamer etc. are mentioned. These may be used alone or in combination of two or more. Among these, a silicone type antifoaming agent is preferable from the viewpoint of excellent foam breaking effect.

<Antiseptic and antifungal agent>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that viscosity, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less from the viewpoint of improving the printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

<Recording medium>
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used. Good image formation is possible even with a non-permeable substrate.
The non-permeable base material is a base material having a surface with low water permeability and absorbability, and includes materials that do not open to the outside even if there are many cavities inside, more quantitatively. In the Bristow method, the water absorption amount from the start of contact to 30 msec ^1/2 is 10 mL / m ² or less.
As said non-permeable base material, plastic films, such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, a polypropylene, polyethylene, a polycarbonate film, can be used conveniently, for example.

  The recording medium is not limited to those used as general recording media, and wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather, and the like can be used as appropriate. Moreover, ceramics, glass, metal, etc. can also be used by adjusting the structure of the path | route which conveys a recording medium.

(Container)
The container of the present invention contains at least one of the cleaning liquid of the present invention or the cleaning liquid and ink in the ink and cleaning liquid set of the present invention in a container, and further includes other members as necessary. Become.

  The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, an ink bag formed of an aluminum laminate film, a resin film, etc. What has at least etc. is mentioned.

(Cleaning method and cleaning device)
The cleaning method of the present invention is a cleaning method for cleaning the nozzle surface of an ink discharge head in an ink discharge apparatus, and is a step of applying a cleaning liquid to a wiping member on a pressing member (hereinafter referred to as a “cleaning liquid applying step”). And a step of wiping the nozzle surface with the wiping member to which the cleaning liquid is applied (hereinafter sometimes referred to as “wiping step”), and further includes other steps as necessary.
As the cleaning liquid, the cleaning liquid of the present invention or the cleaning liquid in the ink and cleaning liquid set of the present invention is used.

The cleaning device used in the present invention is a cleaning device that cleans the nozzle surface of the ink discharge head in the ink discharge device, and is means for applying a cleaning liquid to the wiping member on the pressing member (hereinafter referred to as “cleaning liquid applying means”). And means for wiping the nozzle surface with the wiping member to which the cleaning liquid has been applied (hereinafter also referred to as “wiping means”), and if necessary, other means. Have.
The cleaning liquid is the cleaning liquid of the present invention or the set of the ink and the cleaning liquid of the present invention.

<Cleaning liquid application process and cleaning liquid application means>
The pressing member is not particularly limited as long as it is a member capable of pressing the nozzle surface via the wiping member, and can be appropriately selected according to the purpose. For example, a pressing roller, a pressing roller, and a pressing belt A combination, a wiper, a blade, etc. are mentioned. Among these, a pressure roller is preferable.
The application means is not particularly limited as long as a certain amount of cleaning liquid can be applied, and can be appropriately selected according to the purpose. Examples thereof include application using a dropper, nozzle, spray, dispenser, and coating device.
There is no restriction | limiting in particular as said wiping member, According to the objective, it can select suitably, For example, a nonwoven fabric, cloth, etc. are mentioned. These are preferably wound in a roll shape, and a roll-shaped non-woven fabric is preferable from the viewpoint that dust generation is difficult and reliability is high.

The application amount of the cleaning liquid is preferably controlled by the recording time (discharge time). In this case, it is more preferable that the application amount of the cleaning liquid is selected from a plurality of set values. Examples of the plurality of set values include a cleaning liquid application method (for example, “pressure”, “number of times of application”, “number of application nozzles”).
Further, the application amount of the cleaning liquid is preferably controlled by a pressure applied to a cleaning liquid application nozzle as a cleaning liquid application unit. Furthermore, when the cleaning liquid is applied from a plurality of cleaning liquid application nozzles, the application amount of the cleaning liquid to the wiping member is preferably controlled by the number of the cleaning liquid application nozzles. Furthermore, it is preferable that the amount of the cleaning liquid applied to the wiping member is controlled by the number of times the cleaning liquid is applied from the cleaning liquid application nozzle.

<Wiping process and wiping means>
The wiping step is a step of wiping the nozzle surface with the wiping member to which the cleaning liquid is applied, and is preferably carried out by wiping means.
There is no restriction | limiting in particular as a method of wiping a nozzle surface with the said wiping member to which the said washing | cleaning liquid was provided, It can select suitably according to the objective, For example, the nonwoven fabric as a wiping member to which the washing | cleaning liquid was provided as a pressing member And a method of pressing the nozzle surface of the ink discharge head with a pressing roller.

<Other processes and other means>
Examples of the other steps and the other means include a control step and a control means.
Examples of the control means include devices such as sequencers and computers.

  Here, FIG. 3 is a schematic view showing an example of the cleaning apparatus of the present invention. A cleaning device 300 shown in FIG. 3 is a device that cleans the nozzle surface 301a on the ink discharge side of the nozzle plate 301 of the ink discharge head.

  The cleaning apparatus 300 includes a nonwoven fabric 303 as a wiping member, a cleaning liquid application nozzle 302 as a cleaning liquid application unit, a pressing roller 305 as a pressing member, and a take-up roller 304 that winds up the nonwoven fabric after the wiping process. Yes.

The cleaning liquid is supplied from the cleaning liquid tank via a cleaning liquid supply tube (not shown). By driving a pump provided in the middle of the cleaning liquid supply tube, the cleaning liquid is applied from the cleaning liquid application nozzle 302 to the nonwoven fabric 303 as a wiping member in an application amount of the cleaning liquid according to the recording time. The nonwoven fabric 303 is wound in a roll shape.
As shown in FIG. 3, the nonwoven fabric 303 to which the cleaning liquid is applied is pressed against the nozzle surface 301 a of the ink ejection head 301 by a pressing roller 305 as a pressing member, whereby the nozzle surface 301 a is cleaned. . After the wiping process is completed, the nonwoven fabric 303 is taken up by the take-up roller 304.

  A plurality of cleaning liquid application nozzles 302 as cleaning liquid application means can be provided, and pressure is applied based on control of a control means (not shown), and the application amount of the cleaning liquid can be changed by appropriately changing the pressure. Can be adjusted. Moreover, the application amount of the cleaning liquid can be adjusted by changing the number of nozzles to which the cleaning liquid is applied based on the control of the control means (not shown). Furthermore, the application amount of the cleaning liquid can be adjusted by changing the number of times of applying the cleaning liquid based on the control of the control means (not shown).

Examples of the method for cleaning the nozzle surface on the ink discharge side of the ink discharge head include the following embodiments.
When the cleaning liquid is applied, pressure is applied to the cleaning liquid application nozzle, and the application amount of the cleaning liquid can be adjusted to a desired amount by changing the pressure. Further, it is possible to adjust the application amount of the cleaning liquid by changing the number of nozzles applied by the plurality of cleaning liquid application nozzles, and it is also possible to adjust the application amount by changing the number of times the cleaning liquid is applied from the cleaning liquid application nozzle. . In this way, the wiping member to which the cleaning liquid is applied may be used to wipe the nozzle surface after recording.

(Ink ejection method and ink ejection device)
The ink discharge apparatus of the present invention includes an ink discharge means having an ink discharge head for dropping ink by the action of energy and discharging the ink,
Wiping means for wiping the nozzle surface of the ink discharge head with a wiping member provided with a cleaning liquid, and further having other means as necessary.
The cleaning liquid is the cleaning liquid of the present invention or the set of the ink and the cleaning liquid of the present invention.
The ink ejection device is suitably used for inkjet printing.

The ink discharge method used in the present invention includes an ink discharge step of discharging ink using an ink discharge head for dropping and discharging ink by the action of energy, and
A wiping step of wiping the nozzle surface of the ink discharge head with a wiping member provided with a cleaning liquid, and further including other steps as necessary.
As the cleaning liquid, the cleaning liquid of the present invention or the cleaning liquid in the set of the ink and the cleaning liquid of the present invention is used.
The ink discharge method is suitably used for inkjet printing.

<Recording apparatus and recording method>
The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording method, such as a printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier complex machine, and a three-dimensional modeling apparatus.
In the present invention, the recording apparatus and the recording method are an apparatus capable of ejecting ink, various treatment liquids, and the like to a recording medium, and a method of performing recording using the apparatus. The recording medium means a medium on which ink or various processing liquids can be temporarily attached.
The recording apparatus can include not only a head portion that ejects ink but also means for feeding, transporting, and discharging a recording medium, and other devices called pre-processing devices and post-processing devices. .
The recording apparatus and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, a means for heating and drying the printing surface and the back surface of the recording medium. Although it does not specifically limit as a heating means and a drying means, For example, a warm air heater and an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, what forms patterns, such as a geometric pattern, etc. includes what forms a three-dimensional image.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise specified.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, for example, a continuous paper wound up in a roll shape as a recording medium. Also included are continuous paper printers.
An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective view of the apparatus. FIG. 2 is an explanatory perspective view of the main tank. An image forming apparatus 400 as an example of a recording apparatus is a serial type image forming apparatus. A mechanism unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), yellow (Y) is packaged, for example, an aluminum laminate film It is formed by a member. The ink storage unit 411 is stored in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404. Thus, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and ink can be discharged from the discharge heads 434 to the recording medium.

  The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

  Further, the terms “image formation”, “recording”, “printing”, “printing”, etc. in the terms of the present invention are all synonymous.

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

(Preparation Example 1)
-Preparation of polymer solution-
After replacing the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12 g of lauryl methacrylate, polyethylene glycol 4 g of methacrylate, 4 g of styrene macromer, 0.4 g of mercaptoethanol, and 40 g of methyl ethyl ketone were added, and the temperature was raised to 65 ° C.
Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108 g of lauryl methacrylate, 36 g of polyethylene glycol methacrylate, 60 g of hydroxyl ethyl methacrylate, 36 g of styrene macromer, 3.6 g of mercaptoethanol, 2.4 g of azobismethylvaleronitrile, and 342 g of methyl ethyl ketone Was added dropwise to the flask over 2.5 hours. Further, a mixture of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours, and then aged for 1 hour.
Next, 0.8 g of azobismethylvaleronitrile was added, followed by aging for 1 hour to obtain 800 g of a 50% by mass polymer solution.

(Production Example 1)
<Preparation of ink 1>
-Preparation of magenta pigment dispersion-
28 g of the polymer solution and 26 g of C.I. I. Pigment Red 122, 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of water were stirred, and then kneaded using a roll mill. The obtained paste was put into 200 g of water and stirred, and then, using an evaporator, methyl ethyl ketone and water were distilled off, and a magenta pigment dispersion having a pigment content of 15% by mass and a solid content of 20% by mass. Got.

-Preparation of magenta pigment ink-
1,3-butanediol 15 parts by mass, 1,2-propanediol 15 parts by mass, fluorosurfactant (Zonyl FSO-100, manufactured by DuPont) 0.5 part by mass, urethane resin emulsion (Superflex 500M, solid content) Concentration 45% by mass, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 6 parts by mass (value converted to solid content) and 1,8-octanediol 2 parts by mass were stirred for 1 hour, then 40 parts by mass of the magenta pigment dispersion, After adding the remaining amount of ion-exchanged water so that the total amount becomes 100 parts by mass and stirring for 1 hour, pressure filtration is performed using a polypropylene filter having an average pore size of 1.5 μm to remove coarse particles, and ink 1 Was made.
The composition and content of the obtained ink 1 are shown in Table 1.

In Table 1, the content of the urethane resin emulsion is a numerical value in terms of solid content.

Example 1
-Preparation of cleaning liquid 1-
1 part by mass of an alkylene glycol surfactant (Emulgen LS-106, manufactured by Kao Corporation), 40 parts by mass of diethylene glycol diethyl ether, 2 parts by mass of 2-ethyl-1,3-hexanediol, and a total of 100 parts by mass The remaining amount of water was added and mixed to prepare cleaning liquid 1.

(Examples 2-6 and Comparative Examples 1-5)
-Preparation of cleaning solutions 2-11-
Cleaning solutions 2 to 11 were produced in the same manner as in Example 1 except that the formulation shown in Table 2 and Table 3 below was changed in Example 1.

Next, with respect to the obtained ink 1 and each cleaning liquid, the static surface tension and the contact angle were measured as follows. The results are shown in Tables 2 and 3.
The static surface tension of Ink 1 was 25.0 mN / m at 25 ° C.

<Measurement of static surface tension>
Using an automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Co., Ltd., the magenta pigment ink and each cleaning liquid static surface tension were measured under an environment of 25 ° C. The measurement was performed 5 times, and the average of 3 times excluding the maximum value and the minimum value was taken as the measurement value.

<Measurement of contact angle>
On the slide glass, ink 1 was applied with a wire bar having a diameter of 0.3 mm and dried for 24 hours with a dryer at 50 ° C. to form an ink film with an average thickness of 15 μm.
Using a contact angle meter OCA-200H manufactured by Eihiro Seiki Co., Ltd., 5 μL of each cleaning solution was dropped on the ink film, and the contact angle after landing for 0.5 seconds was calculated from the video shot, and the measured value was obtained. .

In addition, about the brand name of a component in Table 2 and Table 3, and a manufacturing company name, it is as follows.
・ Emulgen LS-106 (manufactured by Kao Corporation, alkylene glycol surfactant)
・ Emulgen LS-110 (manufactured by Kao Corporation, alkylene glycol surfactant)
・ Softanol EP7025 (manufactured by Nissin Chemical Co., Ltd., alkylene glycol surfactant)
-TEGO WET-240 (Evonik's silicone surfactant)
・ Zonyl FS300 (manufactured by DuPont, fluorinated surfactant)
・ Examide M100 (3-methoxy-N, N-dimethylpropionamide, manufactured by Idemitsu Kosan Co., Ltd.)

  Next, the cleaning liquid and ink shown in Table 4 were combined to form a set of ink and cleaning liquid, and evaluation was performed as follows. The results are shown in Table 4.

<Evaluation of permeability of cleaning liquid into nozzle hole>
After printing for 15 minutes using the ink 1 by the ink jet recording apparatus shown in FIG. 1, using the cleaning apparatus shown in FIG. 3, the nozzle surface of the ink discharge head is impregnated with 100 μL of each cleaning liquid (clean fabric) Wiper Anticon GOLD, polyester long fiber, manufactured by Harada Sangyo Co., Ltd.). Immediately after that, 500 drops are printed from a nozzle on a recording medium (super fine paper (manufactured by Seiko Epson Corporation)), the dot density is observed, and the dot density is the same as before wiping the nozzle surface of the ink ejection head. The number of dots until it was measured was measured, and the permeability of the cleaning liquid into the nozzle holes was evaluated according to the following criteria. In addition, it means that it can prevent that a washing | cleaning liquid osmose | permeates in a nozzle hole, so that a dot number is small (image density fall can be prevented).
[Evaluation criteria]
◎: Number of dots is less than 10 ○: Number of dots is 10 or more and less than 30 ×: Number of dots is 30 or more

<Removability>
On the SUS plate, ink 1 was applied with a wire bar having a diameter of 0.3 mm, and dried for 24 hours with a dryer at 50 ° C. to form an ink film having an average thickness of 15 μm.
Using a cleaning apparatus shown in FIG. 3, a constant load (1 N / cm ² ) was applied to a nonwoven fabric (clean wiper Anticon GOLD, polyester filament, manufactured by Harada Sangyo Co., Ltd.) impregnated with 100 μL of each cleaning solution. Wiping was performed, and the number of wipings required until the dried ink on the nozzle surface was exhausted was measured. In addition, it shows that wiping property is so excellent that the frequency | count of wiping is small, and the cleanliness of a nozzle surface can be maintained.

Aspects of the present invention are as follows, for example.
<1> A cleaning liquid used when wiping the nozzle surface of the ink discharge head in the ink discharge apparatus with a wiping member,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
The cleaning liquid according to claim 1, wherein a contact angle of the cleaning liquid with respect to the film obtained by drying the ink is 20 ° or more and 35 ° or less.
<2> The cleaning liquid according to <1>, wherein the cleaning liquid contains an alkylene glycol surfactant.
<3> The cleaning liquid according to any one of <1> to <2>, wherein the cleaning liquid further contains a glycol ether compound.
<4> The cleaning liquid according to <3>, wherein a content of the glycol ether compound is 20% by mass or more and 50% by mass or less.
<5> an ink containing resin particles;
A cleaning solution containing an alkylene glycol surfactant,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
The ink and cleaning liquid set is characterized in that a contact angle of the cleaning liquid with respect to a film obtained by drying the ink is 20 ° or more and 35 ° or less.
<6> The ink and cleaning liquid set according to <5>, wherein the cleaning liquid further contains a glycol ether compound.
<7> The ink and cleaning liquid set according to <6>, wherein the content of the glycol ether compound is 20% by mass or more and 50% by mass or less.
<8> The cleaning liquid according to any one of <1> to <4> or at least one of the cleaning liquid and the ink in the set of the ink and the cleaning liquid according to any one of <5> to <7> in a container It is a storage container characterized by being housed in a container.
<9> A cleaning method for cleaning a nozzle surface of an ink discharge head in an ink discharge apparatus,
Applying a cleaning liquid to the wiping member on the pressing member;
Wiping the nozzle surface with the wiping member to which the cleaning liquid is applied, and
The cleaning liquid according to any one of <1> to <4> or the cleaning liquid in a set of the ink and the cleaning liquid according to any one of <5> to <7> is used as the cleaning liquid. It is a cleaning method.
<10> The cleaning method according to <9>, wherein the pressing member is a pressing roller.
<11> The cleaning method according to any one of <9> to <10>, wherein the wiping member is a nonwoven fabric.
<12> A cleaning device for cleaning a nozzle surface of an ink discharge head in an ink discharge device,
Means for applying a cleaning liquid to the wiping member on the pressing member;
A means for wiping the nozzle surface with the wiping member to which the cleaning liquid has been applied,
The cleaning liquid is the cleaning liquid according to any one of <1> to <4> or the cleaning liquid in the set of the ink and the cleaning liquid according to any one of <5> to <7>. It is a cleaning device.
<13> The cleaning device according to <12>, wherein the pressing member is a pressing roller.
<14> The cleaning device according to any one of <12> to <13>, wherein the wiping member is a nonwoven fabric.
<15> an ink discharge means having an ink discharge head for discharging ink into droplets by the action of energy;
Wiping means for wiping the nozzle surface of the ink discharge head with a wiping member provided with a cleaning liquid,
The cleaning liquid is the cleaning liquid according to any one of <1> to <4> or the cleaning liquid in the set of the ink and the cleaning liquid according to any one of <5> to <7>. An ink ejection device.
<16> The ink ejection device according to <15>, wherein the ink contains resin particles.
<17> The ink ejection device according to any one of <15> to <16>, wherein the wiping member is a nonwoven fabric.
<18> an ink discharge step of discharging ink using an ink discharge head for dropletizing and discharging ink by the action of energy;
A wiping step of wiping the nozzle surface of the ink discharge head with a wiping member provided with a cleaning liquid,
The cleaning liquid according to any one of <1> to <4> or the cleaning liquid in a set of the ink and the cleaning liquid according to any one of <5> to <7> is used as the cleaning liquid. This is an ink discharge method.
<19> The ink ejection method according to <18>, wherein the ink contains resin particles.
<20> The ink ejection method according to any one of <18> to <19>, wherein the wiping member is a nonwoven fabric.

  The cleaning liquid according to any one of <1> to <4>, the set of the ink and the cleaning liquid according to any one of <5> to <7>, the container according to <8>, <9> To <11>, the cleaning device according to any one of <12> to <14>, the ink ejection device according to any one of <15> to <17>, and the above According to the ink ejection method described in any one of <18> to <20>, the above-described problems can be solved and the object of the present invention can be achieved.

400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For each color of black (K), cyan (C), magenta (M), yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

Japanese Patent No. 5566741

Claims (10)

A cleaning liquid used when wiping the nozzle surface of the ink discharge head in the ink discharge apparatus with a wiping member,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
A cleaning liquid, wherein a contact angle of the cleaning liquid with respect to the film obtained by drying the ink is 20 ° or more and 35 ° or less.   The cleaning liquid according to claim 1, wherein the cleaning liquid contains an alkylene glycol surfactant.   The cleaning liquid according to claim 1, wherein the cleaning liquid further contains a glycol ether compound.   The cleaning liquid according to claim 3, wherein the content of the glycol ether compound is 20% by mass or more and 50% by mass or less. An ink containing resin particles;
A cleaning solution containing an alkylene glycol surfactant,
The static surface tension of the cleaning liquid is higher than the static surface tension of the ink,
A set of ink and cleaning liquid, wherein a contact angle of the cleaning liquid with respect to a film obtained by drying the ink is 20 ° to 35 °.   The ink and cleaning liquid set according to claim 5, wherein the cleaning liquid further contains a glycol ether compound.   The ink and cleaning liquid set according to claim 6, wherein a content of the glycol ether compound is 20% by mass or more and 50% by mass or less.   The cleaning liquid according to any one of claims 1 to 4, or at least one of the cleaning liquid and the ink in the set of the ink and cleaning liquid according to any one of claims 5 to 7 is contained in a container. Containment container. A cleaning method for cleaning a nozzle surface of an ink discharge head in an ink discharge apparatus,
Applying a cleaning liquid to the wiping member on the pressing member;
Wiping the nozzle surface with the wiping member to which the cleaning liquid is applied, and
A cleaning method using the cleaning liquid according to any one of claims 1 to 4 or the cleaning liquid in a set of ink and cleaning liquid according to any one of claims 5 to 7 as the cleaning liquid. An ink discharge means having an ink discharge head for dropping ink by the action of energy and discharging the ink;
Wiping means for wiping the nozzle surface of the ink discharge head with a wiping member provided with a cleaning liquid,
An ink ejecting apparatus, wherein the cleaning liquid is the cleaning liquid according to any one of claims 1 to 4 or the cleaning liquid in a set of the ink and the cleaning liquid according to any one of claims 5 to 7.