JP6870402B2 - Ink set, yellow ink, ink container, inkjet printing device, inkjet printing method - Google Patents

Description

The present invention relates to an ink set, yellow ink, an ink container, an inkjet printing apparatus, and an inkjet printing method.

In industrial applications such as advertisements and signboards, in order to improve durability such as light resistance, water resistance, and abrasion resistance, for example, a non-penetrating recording medium such as a plastic film is used, and the non-penetrating recording medium is used. Various inks used in the above have been developed.

As such inks, for example, solvent-based inks using an organic solvent as a solvent, ultraviolet curable inks containing a polymerizable monomer as a main component, and the like are widely used. However, the solvent-based ink is concerned about the influence on the environment due to the evaporation of the organic solvent. Further, in the ultraviolet curable ink, the choice of the polymerizable monomer used may be limited from the viewpoint of safety.
Therefore, an ink set containing a water-based ink that has a low environmental load and can be directly recorded on a non-penetrating recording medium has been proposed (see, for example, Patent Documents 1 to 3).

INDUSTRIAL APPLICABILITY The present invention has excellent adhesion to various printed matter such as a recording medium, the printed matter has high image fastness (scratch resistance, solvent resistance, weather resistance, etc. of the printed matter), and printing is performed on a non-porous recording medium. The purpose is to provide an ink set that can obtain high gloss and high image quality.

The present invention relates to an ink set as described in (1) below.
(1) An ink set having white ink and yellow ink.
Both the white ink and the yellow ink contain water, an organic solvent, a polysiloxane surfactant and polyurethane resin particles, the white ink further contains a metal oxide, and the yellow ink further contains the following structural formula (1). ), The HLB value of the polysiloxane surfactant is 8 or less, and both the white ink and the yellow ink have dissolved oxygen amounts A (ppm) at 20 ° C and 40 ° C. An ink set having a ratio B / A of the dissolved oxygen amount B (ppm) of 0.5 or more.

According to the present invention, an ink set having good storage stability, excellent adhesion to various printed matter, high gloss even when printed on a non-porous recording medium, and high image quality of the printed matter can be obtained. Can be provided.

FIG. 1 is a perspective explanatory view showing an example of a serial type inkjet recording device. FIG. 2 is a schematic view showing a configuration inside the main body of the apparatus of FIG. FIG. 3 is an external perspective view showing an example of an ink ejection head in a printing apparatus. FIG. 4 is a cross-sectional explanatory view of the ink ejection head of FIG. 3 in a direction orthogonal to the nozzle arrangement direction. FIG. 5 is a partial cross-sectional explanatory view of the ink ejection head of FIG. 3 in a direction parallel to the nozzle arrangement direction. FIG. 6 is a plan explanatory view of the nozzle plate of the ink ejection head of FIG. FIG. 7A is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 7B is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 7C is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 7D is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 7E is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 7F is a plan explanatory view of each member constituting the flow path member of the ink ejection head of FIG. FIG. 8A is a plan explanatory view of each member constituting the common liquid chamber member of the ink ejection head of FIG. FIG. 8B is a plan explanatory view of each member constituting the common liquid chamber member of the ink ejection head of FIG. FIG. 9 is a block diagram showing an example of the ink circulation system according to the present invention. FIG. 10 is a diagram illustrating circulation of the ink in the ink ejection head. FIG. 11 is a diagram illustrating circulation of the ink in the ink ejection head.

（７）前記（１）〜（５）のいずれかに記載のインクセットに含まれるインクを収容したインク収容容器。
（８）前記（７）に記載のインク収容容器を有するインク収容部と、
前記インクを吐出させる吐出ヘッドと、を有するインクジェット印刷装置。
（９）前記吐出ヘッドが、個別液室と、前記個別液室にインクを流入させるための流入流路と、インクを前記個別液室から流出させるための流出流路と、を有するインク吐出ヘッドである前記（８）に記載のインクジェット印刷装置。
（１０）前記インクを前記流入流路から前記流出流路に向かって循環させる循環手段をさらに有する前記（９）に記載のインクジェット印刷装置。
（１１）前記（１）〜（５）のいずれかに記載のインクセットに含まれるインクを吐出し、被印刷物に印刷する印刷工程を含むインクジェット印刷方法。
（１２）前記印刷工程が、インクを個別液室に流入させるための流入流路と、インクを前記個別液室から流出させるための流出流路と、を有するインク吐出ヘッドを用い、熱エネルギー及び力学的エネルギーのいずれかをインクに作用させて前記インクを吐出して印刷する印刷工程である前記（１１）に記載のインクジェット印刷方法。
（１３）更に、インクを前記流入流路から前記流出流路に向かって循環させる循環工程を含む前記（１２）に記載のインクジェット印刷方法。
（１４）前記印刷工程の後に加熱工程を有する前記（１１）〜（１３）のいずれかに記載のインクジェット印刷方法。 Hereinafter, the present invention (1) will be described in detail.
In addition, since the following (2) to (14) are also included in the embodiment of the present invention (1), these will also be described.
(2) The ink set according to (1) above, wherein the HLB value of the polysiloxane surfactant is 4.5 to 7.0.
(3) The ink set according to (1) or (2) above, wherein the white ink and the yellow ink contain 1.0% by mass to 2.0% by mass of the polysiloxane surfactant in the ink.
(4) The ink set according to any one of (1) to (3) above, wherein the Tg of the polyurethane resin particles is 0 ° C. or lower.
(5) The white ink and the yellow ink are Y / X when the amount of the polysiloxane surfactant added to the ink is X% by mass and the amount of the polyurethane resin particles added to the ink is Y% by mass. The ink set according to any one of (1) to (4) above, wherein the ink set is 0.5 to 1.5.
(6) The yellow ink used for the ink set according to any one of (1) to (5) above, which comprises water, an organic solvent, a polysiloxane surfactant, polyurethane resin particles, and the following structural formula (1). The HLB value of the polysiloxane surfactant containing the represented compound is 8 or less, and the ratio B / A of the dissolved oxygen amount A (ppm) at 20 ° C. and the dissolved oxygen amount B (ppm) at 40 ° C. Yellow ink with a value of 0.5 or more.

(7) An ink container containing the ink contained in the ink set according to any one of (1) to (5) above.
(8) An ink container having the ink container according to (7) above, and an ink container.
An inkjet printing apparatus comprising an ejection head for ejecting the ink.
(9) The ink ejection head has an individual liquid chamber, an inflow flow path for allowing ink to flow into the individual liquid chamber, and an outflow flow path for causing ink to flow out of the individual liquid chamber. The inkjet printing apparatus according to (8) above.
(10) The inkjet printing apparatus according to (9), further comprising a circulation means for circulating the ink from the inflow channel to the outflow channel.
(11) An inkjet printing method including a printing step of ejecting ink contained in the ink set according to any one of (1) to (5) above and printing on a printed matter.
(12) The printing step uses an ink ejection head having an inflow flow path for flowing ink into the individual liquid chambers and an outflow flow path for flowing out ink from the individual liquid chambers, and uses heat energy and heat energy. The inkjet printing method according to (11) above, which is a printing step in which any of the mechanical energies is applied to the ink to eject the ink for printing.
(13) The inkjet printing method according to (12), further comprising a circulation step of circulating ink from the inflow channel to the outflow channel.
(14) The inkjet printing method according to any one of (11) to (13) above, which has a heating step after the printing step.

そして、前記ポリシロキサン界面活性剤のＨＬＢ値が８以下であり、白色インク及びイエローインクはいずれも、２０℃での溶存酸素量Ａ（ｐｐｍ）と４０℃での溶存酸素量Ｂ（ｐｐｍ）の比Ｂ／Ａが０．５以上である。
白色インク及びイエローインクは必要に応じてその他の成分を含有していても良い。
白色インク及びイエローインクと共にインクセットを構成する他のインクについても使用する界面活性剤はＨＬＢ値が８以下のポリシロキサン界面活性剤とすることが好ましい。 (ink)
The ink set of the present invention has white ink and yellow ink.
Both the white ink and the yellow ink contain water, an organic solvent, a polysiloxane surfactant, and polyurethane resin particles.
Further, the white ink further contains a metal oxide, and the yellow ink further contains a compound represented by the following structural formula (1).

The HLB value of the polysiloxane surfactant is 8 or less, and both the white ink and the yellow ink have a dissolved oxygen amount A (ppm) at 20 ° C. and a dissolved oxygen amount B (ppm) at 40 ° C. The ratio B / A is 0.5 or more.
The white ink and the yellow ink may contain other components if necessary.
The surfactant used for other inks constituting the ink set together with the white ink and the yellow ink is preferably a polysiloxane surfactant having an HLB value of 8 or less.

In general, solvent-based inks are fixed while swelling the impermeable recording medium with the organic solvent in the ink, and therefore have excellent fixability to the impermeable recording medium. However, with conventional water-based inks, the final printed matter is an ink. Since the coating film stays on the recording medium, there is a problem that the fixability of the ink coating film to the recording medium is insufficient and the high-speed recording property is inferior. Further, assuming outdoor use, the weather resistance of printed matter is also required to have properties such as image resistance deterioration that cannot be compared with those for indoor use. However, there is a problem that conventional water-based inks do not have sufficient properties comparable to solvent-based inks.

Among the components contained in the ink, the coloring material has an important function because it is an element that determines the density, color gamut, etc. of the finally obtained image. In the formulation of the ink of the present invention, the present inventors select Pigment Yellow 155 (P.Y.155) represented by the above structural formula (1) as a coloring material for yellow, which is particularly severely deteriorated in terms of weather resistance. It was found that deterioration can be suppressed.

Further, when a printed matter made of a transparent material is used, the present inventors form a base with white ink and then form an image using other color inks. Y. It has been found that the use of 155 has an effect of suppressing color bleeding on the base.
Of the components contained in the ink, the surfactant affects the fixability of the ink on the non-penetrating recording medium for recording, and therefore plays a very important role. The present inventors have found that the fixability of an ink is remarkably improved by adding a compound having an HLB value of 8 or less among polysiloxane surfactants to the ink. The reason is not clear, but it is presumed that when the HLB value is 8 or less, the hydrophobicity is increased and the affinity with various impermeable recording media is improved.

By improving the fixability of the ink to the non-penetrating recording medium, the present inventors can suppress a phenomenon (beading) in which adjacent ink droplets coalesce and shrink after landing even during high-speed recording. We also found that high-quality images can be obtained. Further, it was found that the improvement of the fixing speed can also improve the drying property and the adhesion can be improved, so that the transfer to the backing paper can be suppressed when the recording medium is wound up after recording.

Furthermore, the following findings were obtained regarding the amount of dissolved oxygen contained in the ink. In the process of forming dots on the recording medium after being ejected as ink droplets on the non-penetrating recording medium, the amount of dissolved oxygen A (ppm) at 20 ° C and the amount of dissolved oxygen B (ppm) at 40 ° C Ink that does not meet the requirement that the ratio (B / A) is "B / A ≥ 0.5" is minute on the dot surface due to the dissolution of dissolved gas in the ink in the process of drying the ink and forming dots. Ink bubbles adhere to the image, resulting in a decrease in image gloss and image density. In addition, although the reason is not clear, the durability (solvent resistance) of the image surface against a solvent also decreases. Therefore, the image quality and solvent resistance can be improved by satisfying the requirement of "B / A ≥ 0.5".
Further, it is preferable that B / A ≧ 0.60. 0.90 ≧ B / A ≧ 0.60 is more preferable, 0.80 ≧ B / A ≧ 0.60 is more preferable, and 0.80 is more preferable from the viewpoint of achieving both ink production efficiency and good image formation. It is particularly preferable that ≧ B / A ≧ 0.64.

The amount of dissolved oxygen in the ink can be adjusted by changing the ratio of the solvent and the ratio of water in the ink. Specifically, for example, the amount of dissolved oxygen in the ink can be reduced by reducing the amount of the solvent contained in the ink and increasing the water content without changing the total amount of the ink. Further, in order to improve the image quality, it is preferable that the amount of dissolved oxygen at 20 ° C. is 3 ppm or less. Further, by setting the dissolved oxygen amount at 20 ° C. to 3 ppm or less, the temperature change of the dissolved oxygen amount becomes small, and as a result, the requirement of “B / A ≧ 0.5” can be satisfied.
The value of the dissolved oxygen amount does not change if it is in a sealed state immediately after the ink is prepared.

However, when the HLB value of the surfactant is 8 or less, the balance between water solubility and oil solubility may be biased toward oil solubility. In such a case, in a water-based ink in which the water content exceeds 30% by mass of all the components of the ink, the surfactant becomes difficult to dissolve in the ink, and phase separation which separates into an oil phase and an aqueous phase is likely to occur. As a result, the storage stability of the ink may decrease.

Therefore, the present inventors have found that when polyurethane resin particles are added to an ink, the polysiloxane surfactant can be stabilized in the ink. Thereby, the phase separation of the ink can be eliminated within the operating temperature range assumed as the ink for inkjet recording. By adding polyurethane resin particles, the present inventors have made P.I. Y. It has been found that when 155 is used, there is an effect that the change in viscosity with time is reduced. As a result, the expiration date of the ink can be extended.

<Polysiloxane surfactant>
Examples of the polysiloxane surfactant include a compound having a hydrophilic group or a hydrophilic polymer chain on the side chain of a compound having a polysiloxane structure (silicone-based compound) such as polydimethylsiloxane, and a poly such as polydimethylsiloxane. Examples thereof include a compound having a hydrophilic group or a hydrophilic polymer chain at the end of a compound having a siloxane structure (silicone-based compound). The polysiloxane surfactant may have a polysiloxane structure in its structure.

Examples of the hydrophilic group and the hydrophilic polymer chain include a polyether group (polyethylene oxide, polypropylene oxine, a copolymer thereof, etc.) and polyglycerin (C ₃ Η ₆ O (CH ₂ CH (OH)). CH _{2 O)} n -H, etc.), pyrrolidones, betaines ^{_{(C 3 Η 6 n + (}} C 2 H 4) 2 -CH 2 COO - , etc.), sulfate _{(C 3 H 6 O (C} 2 H 4 O) _n- SO ₃ Na, etc.), phosphate (C ₃ Η ₆ O (C ₂ H ₄ O) _n- P (= O) OHONA, etc.), quaternary salt (C ₃ H ₆ N ⁺ (C ₂ H ₄₎ ) ₃ Cl ^−, etc.) and the like. However, in the chemical formula, n represents an integer of 1 or more. Among these, it is preferable to have a polyether group.

Further, it is possible to use a hydrophilic monomer such as polydimethylsiloxane having a polymerizable vinyl group at the terminal and another monomer copolymerizable (at least a part of the monomer is (meth) acrylic acid or a salt thereof). A vinyl-based copolymer having a silicone-based compound chain such as polydimethylsiloxane in the side chain obtained by the copolymerization of (preferably) is also preferable.

Among these, a compound having a polysiloxane structure and having a hydrophilic polymer chain is preferable, a polyether group is more preferably contained as the hydrophilic polymer chain, and a polysiloxane surfactant is used as a hydrophobic group. A nonionic surfactant having a methylpolysiloxane and having a polyoxyethylene structure as a hydrophilic group is particularly preferable.

The HLB value of the polysiloxane surfactant is 8 or less, preferably 4.5 or more and 7.0 or less. When the HLB value is 8 or less, excellent ink fixability can be ensured even when inkjet recording is performed on various impermeable recording media, and further, when the HLB value is 4.5 or more and 7.0 or less. If there is, it is possible to raise the temperature at which phase separation of the ink does not occur.

Here, the HLB value means the balance between the hydrophilic group and the lipophilic group of the surfactant, and the HLB value takes a value from 0 to 20, the closer it is to 0, the higher the lipophilicity, and the closer it is to 20. Increases hydrophilicity. The HLB value is defined by the following formula (Griffin method).
HLB value = 20 × (sum of formulas of hydrophilic part / molecular weight)

Examples of the polysiloxane surfactant include polyether-modified silicones and polyoxyalkylene group-containing silicone compounds.

As the polysiloxane surfactant, a commercially available product can be used, and examples of the commercially available product include Silface SAG005 (HLB value: 7.0), Sylface SAG008 (HLB value: 7.0), and (. As mentioned above, manufactured by Nissin Chemical Industry Co., Ltd., FZ2110 (HLB: 1.0), FZ2166 (HLB value: 5.8), SH-3772M (HLB value: 6.0), L7001 (HLB value: 7.4). ), SH-3773M (HLB value: 8.0), (above, manufactured by Toray Dow Co., Ltd.), KF-945 (HLB value: 4.0), KF-6017 (HLB value: 4.5), ( As mentioned above, Shin-Etsu Chemical Industry Co., Ltd.), FormBan MS-575 (manufactured by Ultra Ads Inc., HLB value: 5.0) and the like can be mentioned.

The content of the polysiloxane surfactant is preferably 0.1% by mass or more and 4.0% by mass or less, and more preferably 1.0% by mass or more and 2.0% by mass or less, based on the total amount of the ink. When the content is 0.1% by mass or more and 4.0% by mass or less, the fixability of the ink to various impermeable recording media can be improved, and the image quality such as gloss can be improved.
In the white ink and the yellow ink, the amount of the polysiloxane surfactant added to the ink is X% by mass from the viewpoint that the polysiloxane surfactant is stably present in the ink and the change in the viscosity of the ink is suppressed. When the amount of the polyurethane resin particles added to the ink is Y mass%, Y / X is preferably 0.5 to 1.5, and more preferably 0.5 to 1.0.

<Polyurethane resin particles>
The polyurethane resin particles can impart high image glossiness and scratch resistance. Even more surprisingly, in the ink set of the present invention, the yellow ink is P.I. Y. When 155 is used, the change in viscosity with time can be suppressed and the usable period of the ink can be extended. By using the polysiloxane surfactant and the polyurethane resin particles in combination, not only the scratch resistance of the coating film formed after recording but also the solvent resistance can be greatly improved.

The glass transition temperature (Tg) of the polyurethane resin particles is preferably 50 ° C. or lower, more preferably 0 ° C. or lower. When the glass transition temperature is 0 ° C. or lower, the fixing to a printed matter such as a recording medium becomes stronger and the adhesion and fixability are improved. In addition, it is possible to suppress nozzle clogging when ink is ejected from the head and reduce the occurrence rate of ejection defects.
The particle size of the polyurethane resin particles is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency is 20 nm in terms of the maximum number. It is preferably 1000 nm or more, and more preferably 20 nm or more and 150 nm or less. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the polyurethane resin particles is preferably 0.1% by mass or more and 10.0% by mass or less, and 1% by mass or more and 5% by mass or less, 1% by mass or more 2 with respect to the total amount of ink from the viewpoint of improving fixability. .4% by mass or less is more preferable.

Examples of the polyurethane resin particles include polyether polyurethane resin particles, polycarbonate polyurethane resin particles, polyester polyurethane resin particles, and the like.

The polyurethane resin particles are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyurethane resin particles obtained by reacting a polyol with a polyisocyanate.

-Polyol-
Examples of the polyol include polyether polyols, polycarbonate polyols, polyester polyols and the like. These may be used alone or in combination of two or more.

--Polyether polyol ---
Examples of the polyether polyol include those obtained by addition polymerization of an alkylene oxide using at least one compound having two or more active hydrogen atoms as a starting material.

Examples of the compound having two or more active hydrogen atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylolglycol, 1,3-butanediol, 1,4-butanediol, and 1,6-hexane. Examples thereof include diol, glycerin, trimethylolethane, and trimethylolpropane. These may be used alone or in combination of two or more.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran. These may be used alone or in combination of two or more.

The polyether polyol is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining an ink binder capable of imparting extremely excellent scratch resistance, polyoxytetramethylene glycol and polyoxy Propylene glycol is preferred. These may be used alone or in combination of two or more.

--Polycarbonate Polyol ---
Examples of the polycarbonate polyol that can be used for producing the polyurethane resin particles include those obtained by reacting a carbonic acid ester with a polyol, and those obtained by reacting phosgene with bisphenol A and the like. These may be used alone or in combination of two or more.

Examples of the carbonic acid ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like. These may be used alone or in combination of two or more.

Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1, 2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8 − Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcin , Bisphenol-A, Bisphenol-F, 4,4'-biphenol and other relatively low molecular weight dihydroxy compounds; Polyether polyols such as polyethylene glycol, polypropylene glycol and polyoxytetramethylene glycol; Polyhexamethylene adipate, polyhexamethylene Examples thereof include polyester polyols such as succinate and polycaprolactone. These may be used alone or in combination of two or more.

--Polyester polyol ---
Examples of the polyester polyol include those obtained by esterifying a low molecular weight polyol and a polycarboxylic acid, polyester obtained by ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymerization thereof. Examples include polyester. These may be used alone or in combination of two or more.

Examples of the low molecular weight polyol include ethylene glycol and propylene glycol. These may be used alone or in combination of two or more.

Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dodecandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, anhydrides or ester-forming derivatives thereof. These may be used alone or in combination of two or more.

-Polyisocyanate-
Examples of the polyisocyanate include aromatic diisocyanates such as phenylenediocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxyli. Examples thereof include aliphatic or alicyclic diisocyanates such as range isocyanate and 2,2,4-trimethylhexamethylene diisocyanate. These may be used alone or in combination of two or more. Among these, since the ink of the present invention is also used for outdoor applications such as posters and signboards, a coating film having extremely high long-term weather resistance is required, and from the viewpoint of the long-term weather resistance, an alicyclic ring is required. The formula diisocyanate is preferred.

Further, by using at least one kind of alicyclic diisocyanate, it becomes easy to obtain the desired coating film strength and scratch resistance.
Examples of the alicyclic diisocyanate include isophorone diisocyanate and dicyclohexylmethane diisocyanate.
The content of the alicyclic diisocyanate is preferably 60% by mass or more with respect to the total amount of the isocyanate compound.

[Manufacturing method of polyurethane resin particles]
The polyurethane resin particles can be obtained by a conventionally commonly used production method, and examples thereof include the following methods.
First, an isocyanate-terminated urethane prepolymer is produced by reacting the polyol with the polyisocyanate at an equivalent ratio in which the isocyanate group becomes excessive in the absence of a solvent or in the presence of an organic solvent.
Then, the anionic group in the isocyanate-terminated urethane prepolymer is neutralized with a neutralizing agent if necessary, and then reacted with a chain extender, and finally the organic solvent in the system is removed if necessary. Can be obtained by

Examples of the organic solvent that can be used for producing the polyurethane resin particles include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethyl. Examples thereof include amides such as formamide, N-methylpyrrolidone and N-ethylpyrrolidone. These may be used alone or in combination of two or more.
Examples of the chain extender include polyamines and other active hydrogen group-containing compounds.

Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazin, isophoronediamine, 4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexane. Diamines such as diamines; Polyamines such as diethylenetriamine, dipropylenetriamine, and triethylenetetramine; Hydradins such as hydrazine, N, N'-dimethylhydrazine, and 1,6-hexamethylenebishydrazine; dihydrazide succinate, dihydrazide adipic acid , Glutarate dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide and other dihydrazides. These may be used alone or in combination of two or more.

Examples of the other active hydrogen group-containing compound include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and hexamethylene glycol. Glycos such as saccharose, methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, etc. Kind: Water and the like. These may be used alone or in combination of two or more as long as the storage stability of the ink is not deteriorated.

As the polyurethane resin particles, polycarbonate-based polyurethane resin particles are preferable from the viewpoints of water resistance, heat resistance, abrasion resistance, weather resistance, and scratch resistance of images due to the high cohesive force of carbonate groups. In the case of the polycarbonate-based polyurethane resin particles, an ink suitable for printed matter used in a harsh environment such as outdoor use can be obtained.

Commercially available products may be used as the polyurethane resin particles, for example, U-coat UX-485 (polyurethane-based polyurethane resin emulsion), U-coat UWS-145 (polyurethane-based polyurethane resin emulsion), and permarin UA-368T (polyurethane-based polyurethane). Resin emulsion), Permarin UA-200 (polyurethane resin emulsion) (above, manufactured by Sanyo Kasei Kogyo Co., Ltd.), Superflex 300 (polyurethane resin emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Superflex 150 (polyurethane resin) Emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), WBR-600U (polyurethane resin emulsion, manufactured by Taisei Fine Chemical Co., Ltd.) and the like. These may be used alone or in combination of two or more.

<Organic solvent>
The organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include water-soluble organic solvents. The term "water-soluble" means that, for example, 5 g or more is dissolved in 100 g of water at 25 ° C.

Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 2,3-butanediol. 3-Methyl-1,3-butanediol, 3-methoxy-3-methylbutanol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1, 6-Hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol, etc. Polyvalent alcohols such as valent alcohols, ethylene glycol monoethyl 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, dipropylene glycol monomethyl ether, etc. Polyhydric alcohol aryl ethers such as alkyl ethers, ethylene glycol monophenyl ethers and ethylene glycol monobenzyl ethers, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl Nitrogen-containing heterocyclic compounds such as imidazolidinone, ε-caprolactam and γ-butyrolactone, amides such as formamide, N-methylformamide, N, N-dimethylformamide, amines such as monoethanolamine, diethanolamine and triethylamine, dimethyl Examples thereof include sulfur-containing compounds such as sulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. These may be used alone or in combination of two or more.

The content of the organic solvent is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 60% by mass or less, based on the total amount of ink, from the viewpoint of ink drying property and ejection reliability. ..

<Water>
The water is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ion-exchanged water, ultrafiltration water, reverse osmosis water, pure water such as distilled water, and ultrapure water. .. These may be used alone or in combination of two or more.

The water content is preferably 15% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 40% by mass or less with respect to the total amount of ink. When the content is 15% by mass or more, high viscosity can be prevented and discharge stability can be improved, and when it is 60% by mass or less, wettability to a non-permeable recording medium becomes preferable. Image quality can be improved.

<Other ingredients>
The other components include coloring materials, surfactants other than polysiloxane surfactants, antiseptic and fungicides, rust preventives, pH adjusters, and rubbers and plastics such as hindered phenol and hindered phenolamine. Examples include colorless anti-aging agents.

<Color material>
-White ink There is ISO-2469 (JIS-8148) as a standard of whiteness of white ink, and generally, a color material having a whiteness value of 70 or more is used as a color material of white ink.
As the metal oxide used for the white ink, a white metal oxide such as titanium oxide, iron oxide, tin oxide, zirconium oxide, and iron titanate (composite oxide of iron and titanium) can be used.
-Yellow ink As the color material of yellow ink, the compound represented by the structural formula (1) is used.
As a product, P.I. Y. 155 Product name: TONER YELLOW 3GP, manufactured by Clariant Japan.

-Non-white ink The ink set of the present invention may include not only white ink and yellow ink but also other color ink, black ink, gray ink, clear ink, metallic ink, non-white ink and the like.
Examples of the non-white ink include color ink, black ink, gray ink, clear ink, metallic ink and the like. The clear ink does not contain a colorant and means an ink mainly composed of resin particles, an organic solvent and water.
Examples of the other color inks include cyan ink, magenta ink, light cyan ink, light magenta ink, red ink, green ink, blue ink, orange ink, and violet ink.

The color material used for the non-white ink is not particularly limited as long as it exhibits non-white color, and can be appropriately selected depending on the intended purpose, and examples thereof include dyes and pigments. These may be used alone or in combination of two or more. Of these, pigments are preferred.

Examples of the pigment include inorganic pigments and organic pigments.
As the inorganic pigment, for example, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, it is produced by a known method such as a contact method, a furnace method, or a thermal method. Carbon black and the like. These may be used alone or in combination of two or more.

Examples of the organic pigment include azo pigments (including, for example, azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.) and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments). , Kinacridone pigment, dioxazine pigment, indigo pigment, thioindigo pigment, isoindolinone pigment, quinophthalone pigment, etc.), dye chelate (for example, basic dye type chelate, acidic dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black, etc. Can be mentioned. These may be used alone or in combination of two or more.
In addition, hollow resin particles and inorganic hollow particles can also be used.
Among these pigments, those having a good affinity with a solvent are preferably used.

Examples of the pigment for black include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, copper, and iron (CI pigment black 11). , Etc., organic pigments such as aniline black (CI pigment black 1), and the like. These may be used alone or in combination of two or more.

For color, for example, 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; 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 Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Magenta), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219; 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 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; C.I. I. Pigment Greens 1, 4, 7, 8, 10, 17, 18, 36 and the like. These may be used alone or in combination of two or more.

As the dye, for example, 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. Hood 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. Dilekdo 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, 35 and the like can be mentioned. These may be used alone or in combination of two or more.
The yellow ink of the present invention uses the coloring material represented by the structural formula (1), but the above-mentioned yellow coloring material may be used in combination.

Examples of the coloring material used for the metallic ink include fine powder obtained by finely pulverizing a metal simple substance, an alloy, or a metal compound, and more specifically, aluminum, silver, gold, nickel, chromium, tin, zinc, and the like. It may consist of any one or more of a group of metals consisting of indium, titanium, silicon, copper, or platinum, or an alloy obtained by combining these groups of metals, or any of these. It is obtained by finely pulverizing any one or more of oxides, nitrides, sulfides, and carbides of a group of simple metals or alloys.

To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing the pigment, a method of dispersing using a dispersant, And so on.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a self-dispersing pigment obtained by adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) so that it can be dispersed in water. Can be used.
As a method of coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is encapsulated in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin coating pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effects of the present invention are not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low molecular weight dispersant and a high molecular weight dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonate Na formalin condensate can also be suitably used as a dispersant.
One type of dispersant may be used alone, or two or more types may be used in combination.

<Pigment dispersion>
It is possible to obtain ink by mixing a material such as water or an organic solvent with a coloring material. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is preferable to use a disperser for dispersion.
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 the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac 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 mass is used. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
If necessary, the pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifuge, or the like.

The number average particle diameter of the pigment is not particularly limited and may be appropriately selected depending on the intended purpose, but the maximum frequency in terms of the maximum number is preferably 20 nm or more and 150 nm or less. When the number average particle size is 20 nm or more, the dispersion operation and the classification operation become easy, and when it is 150 nm or less, not only the pigment dispersion stability as an ink is improved, but also the ejection stability is excellent. Image quality such as image density is also high, which is preferable.
The number average particle size can be measured using, for example, a particle size analyzer (Microtrack MODEL UPA9340, manufactured by Nikkiso Co., Ltd.).

The content of the coloring material is preferably 0.1% by mass or more and 15% by mass or less, and 1% by mass or more and 10% by mass or less, based on the total amount of ink, from the viewpoint of image density, fixability, and ejection stability. Is more preferable. When the content is 0.1% by mass or more and 15% by mass or less, ejection reliability is high and an image with high saturation can be obtained.

The content of the pigment is preferably 0.1% by mass or more and 15% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less, and 1% by mass or more and 10% by mass or less with respect to the total amount of ink. Especially preferable. When the content is 0.1% by mass or more and 15% by mass or less, the image density, fixability, and ejection stability can be improved.

<Surfactants other than polysiloxane surfactants>
The ink of the present invention may be used in combination with a surfactant other than the polysiloxane surfactant from the viewpoint of ensuring wettability to the recording medium.

The surfactant other than the polysiloxane surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an amphoteric surfactant, a nonionic surfactant, an anionic surfactant, and fluorine. Examples include system surfactants. These may be used alone or in combination of two or more. Among these, nonionic surfactants are preferable from the viewpoint of dispersion stability and image quality.

Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene. Examples thereof include sorbitan fatty acid ester and ethylene oxide adduct of acetylene alcohol. These may be used alone or in combination of two or more.

The content of the surfactant other than the polysiloxane surfactant having an HLB value of 8 or less is preferably 0.1% by mass or more and 5% by mass or less. When the content is 0.1% by mass or more, the wettability to the impermeable recording medium can be ensured, so that the image quality can be improved, and when the content is 5% by mass or less, the ink is less likely to foam. Excellent discharge stability can be obtained.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

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

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjusting agent 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.

[Ink manufacturing method]
As a method for producing the ink, for example, in the white ink, the water, the organic solvent, the polysiloxane surfactant, the polyurethane resin particles, the metal oxide and, if necessary, the other components are stirred. It can be produced by mixing. As the stirring and mixing, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser and the like can be used.

The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. 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 print density and character quality and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'x R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less, more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, more preferably 8 to 11, from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

The ink set of the present invention can be suitably used for inkjet printing.

The printed matter is not particularly limited and is not limited to that used as a general recording medium, and building materials such as wallpaper and flooring, cloth for clothing, textiles, leather and the like can be appropriately used. Further, ceramics, glass, and metal can be used by adjusting the configuration of the path for transporting the printed matter. Next, the recording medium will be described, but the printed matter is not limited to this.

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

By using a recording medium in which the recording medium is colored by applying white ink before the color ink during color recording (colored recording medium), the color development of the color ink can be improved.

<Ink storage>
The ink containing portion includes an ink containing container containing the ink contained in the ink set of the present invention.
The ink container includes the ink contained in the container, and further includes other members appropriately selected as needed.

The ink container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, an ink bag made of an aluminum laminate film, a resin film, or the like. Those having at least such as.
Examples of the ink container include an ink cartridge and a main tank.

As an example of the printing apparatus and printing method using the ink set of the present invention, the recording apparatus and recording method using a recording medium as the printed matter will be described, but the present invention is not limited thereto.

(Inkjet printing method)
The inkjet printing method of the present invention has a printing step of ejecting ink contained in the ink set of the present invention and printing on a printed matter, and may have other steps such as a heating step, if necessary. good.

<< Printing process >>
The printing step is a step of ejecting ink and printing on a printed matter.
The inkjet printing method of the present invention is a printing method in which a stimulus is applied to ink and ink is ejected from an ejection head (recording head) to print.
By stimulating the ink, it becomes possible to eject the ink.

The stimulus is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferably mentioned.

The ejection head uses, for example, a piezoelectric element as a pressure generating means for pressurizing the ink in the ink flow path to deform a vibrating plate forming a wall surface of the ink flow path to change the volume inside the ink flow path. The so-called piezo method of ejecting ink droplets (see, for example, Japanese Patent Publication No. 2-51734); the so-called thermal method of heating ink in the ink flow path using a heat generating resistor to generate bubbles (for example, special). (See Kosho 61-59911); By arranging the vibrating plate and the electrode forming the wall surface of the ink flow path so as to face each other and deforming the vibrating plate by the electrostatic force generated between the vibrating plate and the electrode. , An electrostatic method in which ink droplets are ejected by changing the volume inside the ink flow path (see, for example, Japanese Patent Application Laid-Open No. 6-71882).

The size of the ink droplet to be ejected is preferably 3 pl or more and 40 pl or less, the ejection ejection speed is preferably 5 m / s or more and 20 m / s or less, and the driving frequency thereof is preferably 3 pl or more and 40 pl or less. 1 kHz or higher is preferable, and the resolution thereof is preferably 300 dpi or higher.

<< Heating process >>
The heating step is a step of heating the recording medium on which an image is recorded.
As the inkjet recording method, high image quality recording can be performed on the impermeable substrate, but it is also possible to form an image having higher image quality, abrasion resistance, and adhesion, and to cope with high-speed recording conditions. In order to do so, it is preferable to heat the impermeable substrate after recording. Having a heating step after recording promotes film formation of the resin contained in the ink, so that the image hardness of the recorded material can be improved.

As the device used in the heating step, many known devices can be used, and examples thereof include devices such as forced air heating, radiant heating, conduction heating, high frequency drying, and microwave drying. These may be used alone or in combination of two or more.
The heating temperature can be changed according to the type and amount of the water-soluble organic solvent contained in the ink and the minimum film forming temperature of the resin particles to be added, and further depending on the type of the substrate to be printed. Can be changed.
The heating temperature is preferably high, preferably 35 ° C. or higher and 120 ° C. or lower, more preferably 35 ° C. or higher and 90 ° C. or lower, and particularly preferably 40 ° C. or higher and 90 ° C. or lower, from the viewpoint of drying property and film formation temperature. .. When the heating temperature is 35 ° C. or higher and 120 ° C. or lower, damage due to heat of the impermeable substrate to be printed can be prevented, and non-ejection due to warming of the ink head can be suppressed.

Further, as an example of the printing method in the present invention, as the ink contained in the ink set used in the present invention, an ink (white ink) containing a metal oxide which is a white pigment as a colorant is used as a recording medium. A printing method including a coating step and a printing step of printing with yellow ink containing an ink having a yellow pigment or other non-white ink can also be used. At this time, the white ink can be applied to the entire surface of the recording medium, or may be applied to a part of the recording medium. When it is applied to a part of the recording medium, for example, it may be applied to the same place as the place where recording is performed, or it may be applied to a part which is partly common to the place where recording is performed.

When the white ink is used, it is also effective to use the following printing method. White ink is applied to a recording medium, and yellow ink or non-white ink is printed on the recording medium. According to this method, for example, even when a transparent film is used, the white ink of the present invention is adhered to the surface of the recording medium, so that the visibility of the printed matter can be ensured. Since the white ink has good drying property, high gloss, scratch resistance, etc. even for a non-permeable base material, the white ink is applied to a non-porous base material such as a transparent film in order to improve visibility. It is possible to apply.

Further, by printing on a transparent film with yellow ink or non-white ink and then applying white ink, it is possible to obtain an image having the same excellent visibility.

In the present invention, the ink is not limited to the inkjet printing method and can be widely used. In addition to the inkjet printing method, for example, the blade coating method, the gravure coating method, the gravure offset coating method, the bar coating method, the roll coating method, the knife coating method, the air knife coating method, the comma coating method, the U comma coating method, and the AKKU coating method. , Smoothing coat method, micro gravure coat method, reverse roll coat method, 4 to 5 roll coat method, dip coat method, curtain coat method, slide coat method, die coat method, spray coat method and the like.
As an example of the embodiment, when the white ink is applied to the entire surface of the recording medium, the coating method is applied by a coating method other than the inkjet printing method, and when printing with yellow ink or other non-white ink, the inkjet is used. A mode of printing by a printing method is possible.
As another embodiment, printing using white ink, printing using yellow ink, or other non-white ink can be performed by an inkjet printing method.

Here, an inkjet recording apparatus capable of printing using the ink will be described with reference to the drawings. Although the case of using a non-permeable base material will be described, printing can be performed on a permeable base material such as paper in the same manner. Further, the inkjet recording device includes a serial type (shuttle type) in which a carriage scans, a line type provided with a line type head, and the like, and FIG. 1 is a schematic view showing an example of a serial type inkjet recording device. .. FIG. 2 is a schematic view showing a configuration inside the main body of the apparatus of FIG.

As shown in FIG. 1, the inkjet recording device includes a device main body 101, a paper feed tray 102 mounted on the device main body 101, a paper output tray 103, and an ink cartridge loading unit 104. An operation unit 105 such as an operation key or a display is arranged on the upper surface of the ink cartridge loading unit 104. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 201. 111 is the upper cover and 112 is the front surface of the front cover.

As shown in FIG. 2, the carriage 133 is slidably held in the main scanning direction by the guide rod 131 and the stay 132, which are guide members laid horizontally on the left and right side plates, in the apparatus main body 101, and the main scanning is performed. Mobile scanning is performed by a motor.
The carriage 133 has a plurality of ink ejection ports of a recording head 134 composed of four inkjet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction intersecting the main scanning direction, and the ink droplets are mounted with the ink droplet ejection direction facing downward.
Here, the case where yellow (Y), cyan (C), magenta (M), and black (K) are used has been described, but yellow (Y), cyan (C), magenta (M), and black (K) have been described. The printing method and printing apparatus of the present invention can be obtained by substituting at least one of the above with the white ink or by adding the white ink to the white ink.

The inkjet recording head constituting the recording head 134 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change due to boiling of a liquid film using an electrothermal conversion element such as a heat generating resistor, and a metal phase due to a temperature change. A shape memory alloy actuator that uses change, an electrostatic actuator that uses electrostatic force, or the like provided as an energy generating means for ejecting ink can be used.
Further, the carriage 133 is equipped with a sub tank 135 of each color for supplying ink of each color to the recording head 134. The ink is supplied to and replenished from the ink cartridge 201 loaded in the ink cartridge loading unit 104 via the ink supply tube to the sub tank 135.

The recording head 134 in the inkjet printing apparatus of the present invention may have the inflow channel for allowing ink to flow into the individual liquid chamber and the outflow channel for allowing ink to flow out of the individual liquid chamber. However, the details will be described later.

On the other hand, as a paper feed unit for feeding the base material 142 loaded on the base material loading part (press plate) 141 of the paper feed tray 102, the base material 142 is separated and fed one by one from the base material loading part 141. A separation pad 144 facing the half-moon roller (paper feed roller 143) and the paper feed roller 143 and made of a material having a large friction coefficient is provided, and the separation pad 144 is urged toward the paper feed roller 143.
As a transport unit for transporting the base material 142 fed from the paper feed unit on the lower side of the recording head 134, a transport belt 151 for electrostatically adsorbing and transporting the base material 142 and a paper feed unit The counter roller 152 for sandwiching the base material 142 sent via the guide 145 with the transport belt 151 and the base material 142 fed substantially vertically upward are turned by approximately 90 ° and placed on the transport belt 151. A transfer guide 153 for imitating the pattern and a tip pressurizing roller 155 urged on the transfer belt 151 side by the pressing member 154 are provided, and charging is a charging means for charging the surface of the transfer belt 151. A roller 156 is provided.

The transport belt 151 is an endless belt, which is stretched between the heater type transport roller 157 and the tension roller 158 and can circulate in the belt transport direction. The transport belt 151 includes, for example, a surface layer serving as a substrate adsorption surface formed of a resin material having a thickness of about 40 μm without resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the surface layer. It has a back layer (medium resistance layer, earth layer) made of the same material as the above and whose resistance is controlled by carbon. On the back side of the transport belt 151, a heater-type guide member 161 is arranged corresponding to the printing area by the recording head 134. As a paper ejection unit for ejecting the base material 142 recorded by the recording head 134, a separation claw 171 for separating the base material 142 from the transport belt 151, a paper ejection roller 172, and a paper ejection roller 173 are used. After the base material 142 is hot-air dried by a fan heater, the base material 142 is output to a paper ejection tray 103 below the paper ejection roller 172.

A double-sided paper feed unit 181 is detachably attached to the back surface of the apparatus main body 101. The double-sided paper feed unit 181 takes in the base material 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds the paper again between the counter roller 152 and the transport belt 151. A manual paper feed unit 182 is provided on the upper surface of the double-sided paper feed unit 181.
In the inkjet recording apparatus, the base material 142 is separately fed from the paper feed unit one by one, and the base material 142 fed substantially vertically upward is guided by the guide 145, and the transfer belt 151 and the counter roller 152 are used. It is sandwiched between the two and transported. Further, the tip is guided by the transport guide 153 and pressed against the transport belt 151 by the tip pressurizing roller 155, so that the transport direction is changed by approximately 90 °. At this time, the transport belt 151 is charged by the charging roller 156, and the base material 142 is electrostatically attracted to the transport belt 151 and transported.
Therefore, by driving the recording head 134 in response to the image signal while moving the carriage 133, ink droplets are ejected to the stopped base material 142 to record one line, and the base material 142 is conveyed in a predetermined amount. After that, record the next line. When the recording end signal or the signal that the rear end of the base material 142 reaches the recording area is received, the recording operation is ended and the base material 142 is discharged to the paper ejection tray 103.

The ink ejection head in the inkjet printing apparatus of the present invention may have the following characteristics. An example will be described with reference to FIGS. 3, 4, 5, 6, 7, 7A to 7F, 8A, and 8B. FIG. 3 is an external perspective view showing an example of an ink ejection head in the inkjet printing apparatus of the present invention. FIG. 4 is a cross-sectional explanatory view of the ink ejection head of FIG. 3 in a direction orthogonal to the nozzle arrangement direction. FIG. 5 is a partial cross-sectional explanatory view of the ink ejection head of FIG. 3 in a direction parallel to the nozzle arrangement direction. FIG. 6 is a plan explanatory view of the nozzle plate of the ink ejection head of FIG. 7A to 7F are plan explanatory views of each member constituting the flow path member of the ink ejection head of FIG. 8A and 8B are plan explanatory views of each member constituting the common liquid chamber member of the ink ejection head of FIG.

In the ink ejection head, the nozzle plate 1, the flow path plate 2, and the diaphragm member 3 as a wall surface member are laminated and joined, and the piezoelectric actuator 11 that displaces the diaphragm member 3 and the common liquid chamber member 20 are joined. And a cover 29.

The nozzle plate 1 has a plurality of nozzles 4 for ejecting the ink.
The flow path plate 2 is formed with an individual liquid chamber 6 leading to the nozzle 4, a fluid resistance portion 7 communicating with the individual liquid chamber 6 as the inflow flow path, and a liquid introduction portion 8 communicating with the fluid resistance portion 7. Further, the flow path plate 2 is formed by laminating and joining a plurality of plate-shaped members 41 to 45 from the nozzle plate 1 side, and laminating and joining these plate-shaped members 41 to 45 and the diaphragm member 3 to form a flow path. The member 40 is configured.
The diaphragm member 3 has a filter portion 9 as an opening through the liquid introduction portion 8 and the common liquid chamber 10 formed by the common liquid chamber member 20.
The diaphragm member 3 is a wall surface member that forms the wall surface of the individual liquid chamber 6 of the flow path plate 2. The diaphragm member 3 has a two-layer structure (not limited), and is formed of a first layer that forms a thin-walled portion from the flow path plate 2 side and a second layer that forms a thick-walled portion, and the first layer is an individual liquid. A deformable vibration region 30 is formed in a portion corresponding to the chamber 6.

Here, as shown in FIG. 6, a plurality of nozzles 4 are arranged in a staggered pattern on the nozzle plate 1.
As shown in FIG. 7A, the plate-shaped member 41 constituting the flow path plate 2 includes a through groove portion (meaning a groove-shaped through hole) 6a constituting the individual liquid chamber 6, a fluid resistance portion 51, and the outflow flow. Through groove portions 51a and 52a forming the circulation flow path 52 as a path are formed.
Similarly, as shown in FIG. 7B, the plate-shaped member 42 is formed with a through groove portion 6b forming the individual liquid chamber 6 and a through groove portion 52b forming the circulation flow path 52.
Similarly, as shown in FIG. 7C, the plate-shaped member 43 is formed with a through groove portion 6c constituting the individual liquid chamber 6 and a through groove portion 53a having the nozzle arrangement direction forming the circulation flow path 53 as the longitudinal direction. ..
Similarly, as shown in FIG. 7D, the plate-shaped member 44 includes a through groove portion 6d constituting the individual liquid chamber 6, a through groove portion 7a which is a fluid resistance portion 7, and a through groove portion 8a constituting the liquid introduction portion 8. A through groove portion 53b is formed in which the nozzle arrangement direction constituting the circulation flow path 53 is the longitudinal direction.
Similarly, as shown in FIG. 7E, the plate-shaped member 45 has a through groove portion 6e constituting the individual liquid chamber 6 and a through groove portion 8b (filter downstream side liquid) having the nozzle arrangement direction forming the liquid introduction portion 8 as the longitudinal direction. A through groove portion 53c is formed in which the nozzle arrangement direction forming the circulation flow path 53 is the longitudinal direction.
As shown in FIG. 7F, the diaphragm member 3 is formed with a vibration region 30, a filter portion 9, and a through groove portion 53d whose longitudinal direction is the nozzle arrangement direction constituting the circulation flow path 53.
In this way, by forming the flow path member by laminating and joining a plurality of plate-shaped members, it is possible to form a complicated flow path with a simple structure.

With the above configuration, the flow path member 40 composed of the flow path plate 2 and the diaphragm member 3 has a fluid resistance portion 51, a circulation flow path 52, and circulation along the surface direction of the flow path plate 2 leading to each individual liquid chamber 6. A circulation flow path 53 in the thickness direction of the flow path member 40 leading to the flow path 52 is formed. The circulation flow path 53 leads to the circulation common liquid chamber 50, which will be described later.

On the other hand, the common liquid chamber member 20 is formed with a common liquid chamber 10 to which the ink is supplied from the main tank and the ink cartridge, and a circulation common liquid chamber 50.
As shown in FIG. 8A, the first common liquid chamber member 21 has a through hole 25a for a piezoelectric actuator, a through groove portion 10a serving as a downstream common liquid chamber 10A, and a groove portion 50a having a bottom serving as a circulation common liquid chamber 50. Is formed.
As shown in FIG. 8B, the second common liquid chamber member 22 is formed with a through hole 25b for a piezoelectric actuator and a groove portion 10b serving as an upstream common liquid chamber 10B. Further, as shown in FIG. 3, the second common liquid chamber member 22 is formed with a through hole 71a that serves as one end of the common liquid chamber 10 in the nozzle arrangement direction and a supply port through the supply port 71.
The first common liquid chamber member 21 and the second common liquid chamber member 22 have a through hole through which the other end (the end opposite to the through hole 71a) of the circulation common liquid chamber 50 in the nozzle arrangement direction and the circulation port 81 pass through. 81a and 81b are formed.
In addition, in FIG. 8A and FIG. 8B, the groove portion having the bottom is shown by applying a surface coating (the same applies to the following figures).
As described above, the common liquid chamber member 20 is composed of the first common liquid chamber member 21 and the second common liquid chamber member 22, and the first common liquid chamber member 21 is joined to the diaphragm member 3 side of the flow path member 40. Then, the second common liquid chamber member 22 is laminated and joined to the first common liquid chamber member 21.

Here, the first common liquid chamber member 21 forms a downstream common liquid chamber 10A which is a part of the common liquid chamber 10 leading to the liquid introduction portion 8 and a circulation common liquid chamber 50 leading to the circulation flow path 53. ing. Further, the second common liquid chamber member 22 forms the upstream common liquid chamber 10B which is the rest of the common liquid chamber 10.
At this time, the downstream common liquid chamber 10A and the circulation common liquid chamber 50, which are a part of the common liquid chamber 10, are arranged side by side in the direction orthogonal to the nozzle arrangement direction, and the circulation common liquid chamber 50 is the common liquid chamber 10. It is placed at the position projected inside.
As a result, the dimension (size) of the circulation common liquid chamber 50 is restricted by the dimensions required for the flow path including the individual liquid chamber 6, the fluid resistance portion 7, and the liquid introduction portion 8 formed by the flow path member 40. Is gone.
Then, the circulation common liquid chamber 50 and a part of the common liquid chamber 10 are arranged side by side, and the circulation common liquid chamber 50 is arranged at a position projected in the common liquid chamber 10 so as to be orthogonal to the nozzle arrangement direction. The width of the head in the direction can be suppressed, and the increase in size of the head can be suppressed. The common liquid chamber member 20 forms a circulation common liquid chamber 50 with a common liquid chamber 10 to which the ink is supplied from the head tank or the ink cartridge.

On the other hand, on the side of the diaphragm member 3 opposite to the individual liquid chamber 6, a piezoelectric actuator 11 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3 is provided. It is arranged.
As shown in FIG. 5, the piezoelectric actuator 11 has a piezoelectric member 12 joined on a base member 13, and the piezoelectric member 12 is grooved by half-cut dicing to obtain a required number for one piezoelectric member 12. The columnar piezoelectric elements 12A and 12B are formed in a comb-teeth shape at predetermined intervals.
Here, the piezoelectric element 12A of the piezoelectric member 12 is a piezoelectric element that is driven by giving a drive waveform, and the piezoelectric element 12B is used as a mere column without giving a drive waveform, but all the piezoelectric elements 12A and 12B are driven. It can also be used as a piezoelectric element.
Then, the piezoelectric element 12A is joined to the convex portion 30a which is an island-shaped thick portion formed in the vibration region 30 of the diaphragm member 3. Further, the piezoelectric element 12B is joined to the convex portion 30b which is a thick portion of the diaphragm member 3.

The piezoelectric member 12 is formed by alternately stacking piezoelectric layers and internal electrodes. The internal electrodes are pulled out to their end faces to provide external electrodes, and the flexible wiring member 15 is connected to the external electrodes.
In the ink ejection head configured in this way, for example, by lowering the voltage applied to the piezoelectric element 12A from the reference potential, the piezoelectric element 12A contracts, the vibration region 30 of the vibrating plate member 3 descends, and the individual liquid chamber 6 As the volume expands, the ink flows into the individual liquid chamber 6.
After that, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, and the vibration region 30 of the vibrating plate member 3 is deformed in the direction toward the nozzle 4 to contract the volume of the individual liquid chamber 6. As a result, the ink in the individual liquid chamber 6 is pressurized, and the ink is ejected from the nozzle 4.
Then, by returning the voltage applied to the piezoelectric element 12A to the reference potential, the vibration region 30 of the diaphragm member 3 is restored to the initial position, the individual liquid chamber 6 expands, and a negative pressure is generated. The ink is filled from the chamber 10 into the individual liquid chamber 6. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation for the next ejection is started.
The driving method of this head is not limited to the above example (pull-pushing), and pulling or pushing may be performed depending on the driving waveform. Further, in the above-described embodiment, the laminated piezoelectric element has been described as a means for giving pressure fluctuation to the individual liquid chamber 6, but the present invention is not limited to this, and a thin-film piezoelectric element can also be used. Further, it is possible to use a heat-generating resistor arranged in the individual liquid chamber 6 to generate air bubbles by the heat generated by the heat-generating resistor to cause pressure fluctuation, or to generate pressure fluctuation by using electrostatic force. ..

Next, an example of the ink circulation system using the ink ejection head according to the present embodiment will be described with reference to FIG.

FIG. 9 is a block diagram showing an example of the ink circulation system according to the present invention.
As shown in FIG. 9, the ink circulation system includes a main tank, an ink discharge head, a supply tank, a circulation tank, a compressor, a vacuum pump, a first liquid feed pump, a second liquid feed pump, a regulator (R), and a supply side. It consists of a pressure sensor, a circulation side pressure sensor, and the like. The supply-side pressure sensor is connected between the supply tank and the ink ejection head to the supply flow path side connected to the supply port 71 (see FIG. 3) of the ink ejection head. The circulation side pressure sensor is connected between the ink discharge head and the circulation tank and is connected to the circulation flow path side connected to the circulation port 81 (see FIG. 3) of the ink discharge head.
One of the circulation tanks is connected to the supply tank via the first liquid feed pump, and the other of the circulation tanks is connected to the main tank via the second liquid feed pump. As a result, the ink flows from the supply tank through the supply port 71 into the ink discharge head, is discharged from the circulation port and is discharged to the circulation tank, and further, the ink is discharged from the circulation tank to the supply tank by the first liquid feeding pump. Is sent to circulate the ink.
Further, a compressor (not shown) is connected to the supply tank, and is controlled so that a predetermined positive pressure is detected by the supply side pressure sensor. On the other hand, a vacuum pump (not shown) is connected to the circulation tank, and is controlled so that a predetermined negative pressure is detected by the circulation side pressure sensor. As a result, the negative pressure of the meniscus can be kept constant while circulating the ink through the ink ejection head.
Further, when droplets are ejected from the nozzle of the ink ejection head, the amount of the ink in the supply tank and the circulation tank decreases. Therefore, the second liquid feeding pump is appropriately used from the main tank to the circulation tank. It is desirable to replenish the ink. The timing of replenishing the ink from the main tank to the circulation tank is detected by a liquid level sensor provided in the circulation tank, such as replenishing the ink when the liquid level of the ink in the circulation tank falls below a predetermined height. It can be controlled by the result.

Next, the circulation of the ink in the ink ejection head will be described. As shown in FIG. 3, a supply port 71 communicating with the common liquid chamber and a circulation port 81 communicating with the circulation common liquid chamber 50 are formed at the end of the common liquid chamber member 20. The supply port 71 and the circulation port 81 are connected to a supply tank and a circulation tank (see FIGS. 10 and 11) for storing the ink, respectively, via a tube. Then, the ink stored in the supply tank is supplied to the individual liquid chamber 6 via the supply port 71, the common liquid chamber 10, the liquid introduction section 8, and the fluid resistance section 7.
Further, while the ink in the individual liquid chamber 6 is ejected from the nozzle 4 by driving the piezoelectric member 12, part or all of the ink that remains in the individual liquid chamber 6 without being ejected is the fluid resistance portion 51. , The circulation flow path 52, 53, the circulation common liquid chamber 50, and the circulation port 81, and the circulation to the circulation tank.
The ink circulation can be performed not only when the ink ejection head is operated but also when the operation is stopped. By circulating during the operation suspension, the ink in the individual liquid chamber is constantly refreshed, and the aggregation and sedimentation of the components contained in the ink can be suppressed, which is preferable.

The inkjet printing method of the present invention includes a printing step of ejecting ink contained in the ink set of the present invention and printing on a printed matter.
The printing process uses a discharge head having an inflow channel for allowing ink to flow into the individual liquid chambers and an outflow channel for allowing ink to flow out of the individual liquid chambers, for thermal energy and mechanical energy. It is preferable that the printing step is a printing step in which any of the inks is allowed to act to eject the ink for printing, and further, it is preferable to include a circulation step of circulating the ink from the inflow channel to the outflow channel. As an aspect of the printing process, there is an inkjet printing method which is a printing process in which ink is ejected and printed while circulating ink, and another aspect is
There is an inkjet printing method including a step of stopping the circulation of ink and a step of circulating the ink before ejecting the ink, and as another embodiment, there is an inkjet printing method.
There is an inkjet printing method that includes a step of applying pressure to the ink with a strength that does not eject the ink when the ink is circulated.

(Inkjet printing device)
The inkjet printing apparatus of the present invention has an ink accommodating portion containing ink contained in the ink set of the present invention, and an ejection head for ejecting the ink.
The ejection head is an ink ejection head having an individual liquid chamber, an inflow flow path for inflowing ink into the individual liquid chamber, and an outflow flow path for discharging ink from the individual liquid chamber. Is preferable.
Further, it is preferable to further have a circulation means for circulating the ink from the inflow channel to the outflow channel.

(Printed matter)
The printed matter of the present invention comprises a printed matter formed by using the ink set of the present invention on, for example, a recording medium which is a printed matter.
For example, it can be recorded by an inkjet printing device and an inkjet printing method to produce a printed matter.
Further, the printed matter of the present invention is a printed matter having, for example, a recording medium and a printing layer, which is a printed matter, and the printed matter contains a coloring material, a polysiloxane surfactant, and a polyurethane resin, and is used as the coloring material. , A printed matter having a metal oxide and a compound represented by the structural formula (1), and further having an HLB value of the polysiloxane surfactant of 8 or less.

In addition, image formation, recording, printing, printing, printing, modeling, etc. in the terms of the present application are all synonymous.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Preparation Example 1 of Pigment Dispersion)
<Preparation of black pigment dispersion>
After premixing the following formulation mixture, it is circulated and dispersed for 7 hours in a disc type bead mill (manufactured by Simmal Enterprises Co., Ltd., KDL type, media: using 0.3 mm diameter zirconia balls) to obtain a black pigment dispersion (pigment solid). Concentration: 15% by mass) was obtained.
・ 15 parts by mass of carbon black pigment (trade name: Monarch800, manufactured by Cabot Corporation)
-2 parts by mass of anionic surfactant (trade name: Pionin A-51-B, manufactured by Takemoto Oil & Fat Co., Ltd.)
・ 83 parts by mass of ion-exchanged water

(Preparation Example 2 of Pigment Dispersion)
<Preparation of cyan pigment dispersion>
In Preparation Example 1 of the pigment dispersion, the carbon black pigment was used as Pigment Blue 15: 3.
A cyan pigment dispersion (pigment solid content concentration: 15% by mass) was obtained in the same manner as in Preparation Example 1 of the pigment dispersion except that the product name was changed to LIONOL BLUE FG-7351, manufactured by Toyo Ink Co., Ltd. It was.

(Preparation Example 3 of Pigment Dispersion)
<Preparation of magenta pigment dispersion>
Magenta in the same manner as in Preparation Example 1 of the pigment dispersion, except that the carbon black pigment was changed to Pigment Red 122 (trade name: Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.) in Preparation Example 1 of the pigment dispersion. A pigment dispersion (pigment solid content concentration: 15% by mass) was obtained.

(Preparation Example 4 of Pigment Dispersion)
<Preparation of Yellow Pigment Dispersion 1>
In Preparation Example 1 of the pigment dispersion, the yellow pigment is the same as in Preparation Example 1 of the pigment dispersion, except that the carbon black pigment is changed to Pigment Yellow 155 (trade name: TONER YELLOW 3GP, manufactured by Clariant Japan Co., Ltd.). Dispersion 1 (pigment solid content concentration: 15% by mass) was obtained.

(Preparation Example 5 of Pigment Dispersion)
<Preparation of yellow pigment dispersion 2>
In Preparation Example 1 of the pigment dispersion, the carbon black pigment was changed to Pigment Yellow 74 (trade name: First Yellow 531; manufactured by Dainichiseika Kogyo Co., Ltd.) in the same manner as in Preparation Example 1 of the pigment dispersion. , Yellow pigment dispersion 2 (pigment solid content concentration: 15% by mass) was obtained.

(Preparation Example 6 of Pigment Dispersion)
<Preparation of white pigment dispersion>
Titanium oxide (trade name: STR-100W, manufactured by Sakai Chemical Industry Co., Ltd.) 25 parts, pigment dispersant (trade name: TEGO Dispers 651, manufactured by Evonik Industries, Ltd.) 5 parts, water 70 parts are mixed, and a bead mill (trade name: Research) A white pigment dispersion was obtained by dispersing 0.3 mmΦ zirconia beads at a filling rate of 60% and 8 m / s for 5 minutes at a laboratory (manufactured by Simmal Enterprises Co., Ltd.).

<Preparation of polyurethane resin emulsion 1>
100 parts by mass of methyl ethyl ketone, polyester polyol (1) (iPA / AA = 6/4 (molar ratio) and EG / NPG = 1) in a 2 L reactor equipped with a stirrer, thermometer, nitrogen seal tube and cooler. Number of polyester polyols obtained from / 9 (molar ratio) Average molecular weight = 2,000, average number of functional groups = 2, iPA: isophthalic acid, AA: adipic acid, EG: ethylene glycol, NPG: neopentyl glycol) 345 parts by mass and 9.92 parts by mass of DMPA 2,2-dimethylol propionate were charged and mixed uniformly at 60 ° C.
Then, 45.1 parts by mass of triethylene glycol diisocyanate TEGDI and 0.08 parts by mass of dioctyltin dilaurate DOTDL were charged and reacted at 72 ° C. for 3 hours to obtain a polyurethane solution.
80 parts by mass of IPA, 220 parts by mass of MEK, 3.74 parts by mass of TEA, and 596 parts by mass of water were added to this polyurethane solution for phase inversion, and then MEK and IPA were removed by a rotary evaporator. Polyurethane resin emulsion 1 was obtained.
After cooling the obtained aqueous emulsion to room temperature, ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the solid content to 30% by mass and pH 8.
Using this polyurethane resin emulsion 1, the glass transition point (= Tg) measured by "Thermo plus EVO2" (manufactured by Rigaku) was 0 ° C.

<Preparation of polyurethane resin emulsion 2>
Polycarbonate diol (reaction product of 3-methyl-1,5-pentanediol and diphenyl carbonate) (number average molecular weight Mn = 1200) 1500 g, 2,2- 220 g of dimethylolpropionic acid (DMPA) and 1347 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream and heated to 60 ° C. to dissolve the DMPA. Next, 1445 g of 4,4′-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurylate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer. The reaction mixture was cooled to 80 ° C., and 4340 g of the mixture was added and mixed with 149 g of triethylamine, and 4340 g was extracted and added to a mixed solution of 5400 g of water and 15 g of triethylamine under strong stirring. Next, 1500 g of ice was added, 626 g of a 35% 1,6-hexamethylenediamine aqueous solution was added to carry out a chain extension reaction, the solvent was distilled off so that the solid content concentration became 30%, and the polyurethane resin emulsion 2 was prepared. Obtained.
Using this emulsion 2, the glass transition point (= Tg) measured by "Thermo plus EVO2" (manufactured by Rigaku) was 10 ° C.

<Procurement of polyurethane resin emulsions 3 to 5>
The following commercially available products were used as the polyurethane resin emulsions 3 to 5.
-Polyurethane resin emulsion 3: Product name: Superflex 300, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., solid content concentration: 30% by mass, Tg: -42 ° C.
-Polyurethane resin emulsion 4: Product name: Superflex 150, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., solid content concentration: 30% by mass, Tg: 40 ° C.
-Polyurethane resin emulsion 5: Product name: WBR-600U, manufactured by Taisei Fine Chemical Co., Ltd., solid content concentration: 34% by mass, Tg: -30 ° C.

<Procurement of acrylic-silicone resin emulsion>
In Comparative Example 2, the following commercially available products were used as the acrylic-silicone resin emulsion used in place of the polyurethane resin emulsion.
-Acrylic-silicone resin emulsion: Product name: AE980, manufactured by E-Tech Co., Ltd., solid content concentration: 50% by mass, Tg: -14 ° C.

Further, in Tables 1 and 2, the product names of the ingredients and the names of the manufacturers are as follows.
-KF-945: Polyether-modified silicone 1
(Polysiloxane surfactant, manufactured by Shin-Etsu Chemical Co., Ltd., HLB value: 4.0)
-KF-6017: Polyether-modified silicone 2
(Polysiloxane surfactant, manufactured by Shin-Etsu Chemical Co., Ltd., HLB value: 4.5)
SH-3772M: Polyether-modified silicone 3
(Polysiloxane surfactant, manufactured by Toray Dow Co., Ltd., HLB value: 6.0)
Silface SAG005: Polyether-modified silicone 4
(Polysiloxane surfactant, manufactured by Nissin Chemical Industry Co., Ltd., HLB value: 7.0
L7001: Polyether-modified silicone 5
(Polysiloxane surfactant, manufactured by Toray Dow Co., Ltd., HLB value: 7.4)
-KF-353: Polyether-modified silicone 6
(Polysiloxane surfactant, manufactured by Shin-Etsu Chemical Co., Ltd., HLB value: 10.0)
・ Proxel LV: Preservative manufactured by Abyssia Co., Ltd.

(Example 1)
20% by mass of black pigment dispersion, 1.0% by mass of polyether-modified silicone 2 (polysiloxane surfactant, trade name: KF-6017, manufactured by Shinetsu Chemical Industry Co., Ltd., HLB value: 4.5), polyurethane resin emulsion 5 (WBR-600U / Taisei Fine Chemical Co., Ltd., non-volatile content 34%, Tg = -30 ° C) 1.0% by mass (as resin solid content concentration), 1,2-propanediol 12% by mass, 1,3 − Propanediol 10% by mass, 1,2-butanediol 3% by mass, 2,3-butanediol 3% by mass, 3-methoxy-3-methylbutanol 3% by mass, 2-methyl-2,4-pentanediol 3 Add mass%, dipropylene glycol monomethyl ether 4% by mass, trade name as preservative: Proxel LV (manufactured by Abyssia) 0.1% by mass, and high pure water so as to be the remaining amount, mix and stir, and average pore size. Ink 1 (black ink) was produced by filtering with a polypropylene filter having a diameter of 0.2 μm (trade name: Betafine polypropylene pleated filter PPG series, manufactured by 3M).
Ink 1 (black ink) except that the black pigment dispersion was replaced with a cyan pigment dispersion, a magenta pigment dispersion, a yellow pigment dispersion 1, or a white pigment dispersion in the preparation of the ink 1 (black ink). Ink 1 (cyan ink), ink 1 (magenta ink), ink 1 (yellow ink), and ink 1 (white ink) were prepared in the same manner as in the above preparation, and these were used as ink set 1.

(Examples 2 to 11 and Comparative Examples 1 to 4)
Ink sets 2 to 11 of Examples 2 to 11 and Comparative Example 1 in the same manner as in Example 1 except that the compositions and contents shown in Tables 1 and 2 below were changed in Example 1. Ink sets 12 to 15 of ~ 4 were prepared.
The numerical values of the resin emulsions in Tables 1 and 2 indicate the solid content concentration of the resin.

Next, "storage stability", "viscosity stability over time", "fixing property (beading)", "solvent resistance", "image glossiness", "adhesion", and "image" are as follows. "Blur" was evaluated. The results are shown in Table 3.

Considering the use for outdoor use, the evaluation of "fixing property (beading)" is considerably stricter than that of recording on ordinary paper.

<Storage stability (appearance evaluation)>
Regarding the obtained yellow ink and white ink of the ink sets of Examples 1 to 11 and Comparative Examples 1 to 4, each ink is placed in a container having a capacity of 30 mL (trade name: Glass Bayer SV-30, manufactured by Nichiden Rika Glass Co., Ltd.). The cells were stored at 50 ° C., 60 ° C., and 70 ° C. for 7 days, visually observed, and "storage stability" was evaluated based on the following criteria. It is desirable in actual use that the evaluation is B or higher. The yellow ink using the yellow pigment dispersion and the white ink using the white pigment dispersion were individually evaluated.
[Evaluation criteria]
A: No phase separation in 70 ° C storage B: No phase separation in 60 ° C storage but phase separation in 70 ° C storage C: No phase separation in 50 ° C storage but in 60 ° C storage Phase-separated D: Phase-separated when stored at 50 ° C.

<Viscosity stability over time>
For the obtained yellow ink and white ink of the ink sets of Examples 1 to 11 and Comparative Examples 1 to 4, each ink was sealed in a 50 mL glass vial (manufactured by Nichiden Rika Glass Co., Ltd.) and placed in a constant temperature bath at 70 ° C. After storage for 14 days, the viscosity of the ink was measured. The rate of change in viscosity of the ink after storage with respect to the viscosity of the ink before storage was calculated, and "viscosity stability over time" was evaluated based on the following evaluation criteria. It is desirable in actual use that the evaluation is B or higher. The yellow ink using the yellow pigment dispersion and the white ink using the white pigment dispersion were individually evaluated.
The viscosity was measured using a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). The measurement conditions were 25 ° C., a standard cone rotor (1 ° 34'x R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
[Evaluation criteria]
A: Viscosity change rate is less than 5% B: Viscosity change rate is 5% or more and less than 10% C: Viscosity change rate is 10% or more and less than 15% D: Viscosity change rate is 15% or more

[Formation of solid image]
The ink sets of Examples 1 to 11 and Comparative Examples 1 to 4 obtained by forming a base using white ink, printing on it with yellow ink to form a solid image, and performing the following evaluations. Of these, the yellow ink obtained using the yellow pigment dispersion and the white ink obtained using the white pigment dispersion were filled in an inkjet printer (device name: IPSiO GXe5500 remodeling machine, manufactured by Ricoh Co., Ltd.) to form a polyvinyl chloride film. A solid white image was obtained with an ^{ink adhesion amount of 0.6 g / cm 2} with respect to (CPPVWP1300, manufactured by Sakurai Co., Ltd., hereinafter also referred to as "PVC film"). A solid image of yellow ink is formed in a strip shape on a white solid image with an ink adhesion amount of 0.6 g / cm ² , and a solid image having a yellow portion of the yellow solid image and a white portion of the white solid image is formed. Formed. The solid image was dried on a hot plate (NINOS ND-1, manufactured by AS ONE Corporation) set at 80 ° C. for 1 hour.

<Fixability (beading)>
The recording unevenness of the solid image of the yellow portion formed on the PVC film was visually observed, and the "fixability (beading)" was evaluated based on the following evaluation criteria. It is desirable in actual use that the evaluation is B or higher.
[Evaluation criteria]
A: Very good (no beading at all)
B: Good (slight beading was observed)
C: Normal (there was beading)
D: Bad (there was significant beading)

<Solvent resistance>
The solid image having the yellow portion and the white portion was immersed in a 60 mass% ethanol aqueous solution at room temperature (25 ° C.) for 24 hours, then naturally dried at room temperature (25 ° C.) for 24 hours, and then X-Rite938 ( Using X-Rite), measure the image density, calculate the amount of decrease in the image density value in the image density after immersion with respect to the initial density of the image before immersion, and based on the following evaluation criteria, "tolerance""Solventivity" was evaluated. It is desirable in actual use that the evaluation is B or higher. The yellow part and the white part were evaluated individually.
〔Evaluation criteria〕
AA: Decrease in image density value is less than 5% A: Decrease in image density value is less than 10% B: Decrease in image density value is 10% or more and less than 20% C: Decrease in image density value is 20% or more

<Image glossiness>
The 60 ° glossiness of the yellow part of the solid image having the yellow part and the white part was measured four times with a glossiness meter (manufactured by BYK Gardener, 4501), and the average value of the glossy values was calculated and used as the following evaluation criteria. Based on this, the "image glossiness" was evaluated. It is desirable in actual use that the evaluation is B or higher.
〔Evaluation criteria〕
AA: Gloss value is 100 or more A: Gloss value is 90 or more and less than 100 B: Gloss value is 80 or more and less than 90 C: Gloss value is less than 80

<Adhesion>
For the solid image having the yellow part and the white part, the number of remaining squares of 100 test squares was counted by a grid peeling test using a cloth adhesive tape (manufactured by Nichiban Co., Ltd., 123LW-50), and the following The "adhesion" to the PVC film was evaluated based on the evaluation criteria. It is desirable in actual use that the evaluation is B or higher. The yellow part and the white part were evaluated individually.
〔Evaluation criteria〕
A: Number of remaining cells is 98 or more B: Number of remaining cells is 90 or more and less than 98 C: Number of remaining cells is 70 or more and less than 90 D: Number of remaining cells is less than 70

<Evaluation of image bleeding>
The yellow portion of the solid image having the yellow portion and the white portion was visually observed to evaluate bleeding.
The evaluation was performed on a 5-point scale. Of these, evaluation values B and above were set as evaluation values that did not cause any practical problems.

<Blur evaluation>
AA: No bleeding A: Very slight bleeding is confirmed in some parts B: Slight bleeding is confirmed in the entire boundary C: Bleeding is confirmed in the entire boundary D: Occurrence of bleeding is confirmed throughout the band pattern

<Evaluation of dissolved oxygen amount>
The white inks and yellow inks of the obtained ink sets of Examples 1 to 11 and Comparative Examples 1 to 4 were evaluated individually.
The amount of dissolved oxygen in the ink is stored in a sealed container until the evaluation is performed after the ink is manufactured, and the ink immediately after opening the sealed container is used for evaluation.
Using a dissolved oxygen meter (product model number: TOX-999iB, manufactured by Toko Kagaku Kenkyusho Co., Ltd.), the amount of dissolved oxygen in the white ink and yellow ink of the obtained ink sets of Examples 1 to 11 and Comparative Examples 1 to 4 was measured. Then, the dissolved oxygen amount A at a liquid temperature of 20 ° C. and the dissolved oxygen amount B at a liquid temperature of 40 ° C. were measured. Table 3 shows the results of obtaining B / A from the measurement results.

<Discharge reliability>
An inkjet printer (device name: IPSiO GXe5500 modified machine, manufactured by Ricoh Co., Ltd.) was evaluated by mounting an ink ejection head having a circulation mechanism shown in FIGS. 3 to 11 as an ink ejection head. The ink container was filled with ink and left for 24 hours in an environment of temperature: 35 ° C. and humidity: 30% RH. During leaving, the circulation mechanism was operated once an hour for 2 minutes.
After being left to stand, the circulation mechanism was operated for 1 minute before printing. In an environment of temperature: 35 ° C. and humidity: 30% RH, a nozzle check pattern is printed on the PVC film to check the number of nozzles ejected with ink for the total number of nozzles 384, and the following criteria are used. Evaluated in. It is desirable in actual use that the evaluation is B or higher. As the evaluation ink, the yellow ink and the white ink obtained in Example 2 were used.
-Evaluation criteria-
A: Number of discharge nozzles is 368 or more B: Number of discharge nozzles is 192 or more and less than 368 C: Number of discharge nozzles is less than 192

Examples 1, Example 2, Examples 4 to 6, and Examples 9 to 11 are preferable examples of the present invention, which have excellent adhesion to a PVC film and are also high when printed on a non-permeable recording medium. It can be seen that an image glossiness can be obtained, and an image having solvent resistance and fixability can be obtained.
Examples 3, 7, and 8 are more preferable examples of the present invention, have high image glossiness, and can suitably suppress image bleeding. In addition, the solvent resistance of the image can be improved.

On the other hand, in Comparative Examples 1 to 4, the yellow ink had a polysiloxane surfactant having an HLB value of 8 or less, polyurethane resin particles, and P.I. Y. This is an example in which the ink does not contain all of 155 and the dissolved oxygen amount B / A ≧ 0.5, and Comparative Example 1 has better storage stability, fixability, and solvent resistance of the ink than Example 1. It was particularly inferior. Comparative Example 2 was particularly inferior in storage stability, fixability and adhesion to Example 1. Comparative Example 3 was particularly inferior in image bleeding to that of Example 1. Comparative Example 4 was particularly inferior in solvent resistance and image glossiness as compared with Example 1.

From the results in Table 3 above, it can be seen that the ink of the present invention is suitable for outdoor use.
Further, when an ink ejection jet having a circulation mechanism is introduced into the ejection head, the ejection reliability is further improved.

<Evaluation of the effect on heat drying>
Using the white ink of Example 1, a solid white image was obtained with an ink adhesion amount of 0.6 g / cm ^{2 on the PVC film.} Yellow ink obtained by using a yellow pigment dispersion, magenta ink obtained by using a magenta pigment dispersion, and cyan pigment dispersion in strips on a white solid image with an ink adhesion amount of 0.6 g / cm ^2. Solid images of the cyan ink obtained by using the body and the black ink obtained by using the black pigment dispersion were formed at intervals.
As shown in Table 5 below, the heating conditions (heating temperature, heating time) after printing were set for the solid image, and the fixability (beading), drying property, and image bleeding were evaluated. The results are shown in Table 5. In Table 5, 1-8 is an example in which the heat treatment is not performed.
The IPSiO GXe5500 remodeling machine modifies the IPSiO GXe5500 machine so that ^{a record equivalent to a recording speed of 30 m 2} / hr can be reproduced in A4 size with a printing width of 150 cm, and the hot plate is installed for printing. A device modified so that the subsequent heating conditions (heating temperature, heating time) could be changed was used.
<Dryness>
The filter paper was pressed against the solid portion of the solid image after drying, the transfer of ink to the filter paper was visually observed, and the "dryness" was evaluated based on the following evaluation criteria.
[Evaluation criteria]
A: No transfer to filter paper B: Partial transfer to filter paper was observed. Fixability (beading) and image bleeding are the same as the above-mentioned <fixing property (beading)> and <image bleeding evaluation>. It was evaluated according to the evaluation criteria of.

本発明のインクセットを用いれば、白色インクとイエローインクに加え、その他のカラーインクを組み合わせて画像形成した場合にも、定着性、乾燥性に優れ、画像にじみを生じない画像形成を行うことができる。

By using the ink set of the present invention, even when an image is formed by combining white ink and yellow ink with other color inks, it is possible to form an image that is excellent in fixability and dryness and does not cause image bleeding. it can.

(About Fig. 1 and Fig. 2)
101 Device body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading unit 105 Operation unit 111 Top cover 112 Front of front cover 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Base material loading unit 142 Base material 143 Paper Feed Roller 144 Separation Pad 145 Guide 151 Transport Belt 152 Counter Roller 153 Transport Guide 154 Pressing Member 155 Tip Pressurizing Roller 156 Charging Roller 157 Transport Roller 158 Tension Roller 161 Guide Member 171 Separation Claw 172 Separation Roller 173 Paper Discharge Roller 181 Double-sided paper feed unit 182 Manual paper feed unit 201 Ink cartridge

(About FIGS. 3 to 8 and 10 to 11)
1 Nozzle plate 2 Flow path plate 3 Vibrating plate member 4 Nozzle 6 Individual liquid chambers 6a, 6b, 6c, 6d, 6e Through groove part that constitutes the individual liquid chamber 7 Fluid resistance part 7a Through groove part that is a fluid resistance part 8 Liquid introduction part 8a, 8b Through groove part 9 filter part 10 common liquid chamber 10A downstream side common liquid chamber 10a through groove part 10B upstream side common liquid chamber 10b groove part 11 piezoelectric actuator 12 piezoelectric member 12A, 12B piezoelectric element 13 base member 15 Flexible wiring member 20 Common liquid chamber member 21 1st common liquid chamber member 22 2nd common liquid chamber member 25a, 25b Through hole for piezoelectric actuator 29 Cover 30 Vibration region 30a, 30b Convex part 40 Flow path member 41-45 Plate-shaped member 50 Circulation common liquid chamber 50a Groove 51 Fluid resistance 51a Through groove 52, 53 Circulation channel 52a, 52b Through groove 53a, 53b, 53c, 53d Through groove 71 Supply port 71a Through hole 81 Circulation port 81a, 81b Through hole

Japanese Unexamined Patent Publication No. 2011-252169 Japanese Patent No. 5772089 Japanese Unexamined Patent Publication No. 2014-205767

Claims (13)

An ink set having white ink and yellow ink.
Both the white ink and the yellow ink contain water, an organic solvent, a polysiloxane surfactant, and polyurethane resin particles.
The Tg of the polyurethane resin particles is 0 ° C. or lower, and the temperature is 0 ° C. or lower.
The white ink further contains a metal oxide, the yellow ink further contains a compound represented by the following structural formula (1), the HLB value of the polysiloxane surfactant is 8 or less, and the white ink and the white ink Each of the yellow inks is an ink set in which the ratio B / A of the dissolved oxygen amount A (ppm) at 20 ° C. and the dissolved oxygen amount B (ppm) at 40 ° C. is 0.5 or more.

The ink set according to claim 1, wherein the polysiloxane surfactant has an HLB value of 4.5 to 7.0. The ink set according to claim 1 or 2, wherein the white ink and the yellow ink contain 1.0% by mass to 2.0% by mass of the polysiloxane surfactant in the ink. The white ink and the yellow ink have a Y / X of 0. When the amount of the polysiloxane surfactant added to the ink is X% by mass and the amount of the polyurethane resin particles added to the ink is Y% by mass. The ink set according to any one of claims 1 to 3 , which is 5 to 1.5. The yellow ink used for the ink set according to any one of claims 1 to 4 , which contains water, an organic solvent, a polysiloxane surfactant, polyurethane resin particles, and a compound represented by the following structural formula (1). The HLB value of the polysiloxane surfactant is 8 or less, and the ratio B / A of the dissolved oxygen amount A (ppm) at 20 ° C. to the dissolved oxygen amount B (ppm) at 40 ° C. is 0.5 or more. A certain yellow ink.

An ink container containing the ink contained in the ink set according to any one of claims 1 to 4. An ink container having the ink container according to claim 6 and an ink container.
An inkjet printing apparatus comprising an ejection head for ejecting the ink. A claim that the ejection head is an ink ejection head having an individual liquid chamber, an inflow flow path for inflowing ink into the individual liquid chamber, and an outflow flow path for discharging ink from the individual liquid chamber. Item 7. The inkjet printing apparatus according to item 7. The inkjet printing apparatus according to claim 8 , further comprising a circulation means for circulating the ink from the inflow channel to the outflow channel. An inkjet printing method including a printing step of ejecting ink contained in the ink set according to any one of claims 1 to 4 and printing on a printed matter. The printing process uses an ink ejection head having an inflow flow path for flowing ink into the individual liquid chambers and an outflow flow path for flowing out ink from the individual liquid chambers, and uses thermal energy and mechanical energy. The inkjet printing method according to claim 10 , which is a printing step in which any of the above is acted on the ink to eject the ink for printing. The inkjet printing method according to claim 11 , further comprising a circulation step of circulating ink from the inflow channel to the outflow channel. The inkjet printing method according to any one of claims 10 to 12 , which has a heating step after the printing step.

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