JP3387585B2 - Transfer type ink composition for inkjet recording - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition for a transfer type ink jet recording apparatus. 2. Description of the Related Art In transfer-type ink jet recording, ink droplets are temporarily ejected from an ink jet print head onto a transfer medium, and most of the water contained in the ink droplets is heated and evaporated. It uses a process of transferring images onto a recording medium, and has a feature that the outline of an output image is sharper than that in which recording is performed by directly discharging ink onto a recording medium. [0003] As an ink composition suitable for the transfer type ink jet recording, an example comprising water, a dye and a polyhydric alcohol is disclosed in Japanese Patent Application Laid-Open No. 62-92849 and US Patent No. 453.
No. 8156 and the like. However, in these ink compositions,
The outline of the output image was not sufficiently sharp. Therefore, the ink composition is suitable for direct printing type ink jet recording for printing directly on a recording medium or the like, and has stability of ink discharge from nozzles of a print head, fixability on a recording medium, and storage stability of ink. For the purpose of improvement,
Aqueous recording inks containing water, a colorant and a water-soluble resin (JP-A-56-147683, JP-A-3-134)
No. 073) for a transfer type ink jet recording apparatus, a transfer image having a sharp outline of an output image could be obtained. However, when the conventional water-soluble resin-containing ink composition is used in a transfer type ink jet recording apparatus, the following problems have not been solved at all. [0007] It is the following points. [0008] Ink transfer residue on a transfer medium at the time of transfer occurs due to a difference in print pattern such as density of a recorded image and the length of time from when ink is ejected until transfer. The movement of the retained ink for a short time until the transfer on the transfer medium and the deformation of the ink image are caused. Due to the above problems, it has been more difficult than expected to always ensure a good and stable transfer image. The present invention solves these problems,
The purpose is to stably transfer the ink image obtained on the transfer medium to the recording medium without any transfer residue or deformation of the ink image, without being affected by the print pattern or the time from ink discharge to transfer. It is an object of the present invention to provide a new transfer-type ink jet recording ink composition which is capable of performing the above. [0011] The ink composition for transfer-type ink jet recording of the present invention comprises at least water, a pigment, a water-soluble resin and a water-soluble organic solvent. An alkyl acrylate-alkyl (meth) acrylate- (meth) acrylic acid which is made water-soluble by neutralizing the water-soluble resin with an alkali agent, and is 100% by weight or more based on the pigment, and 5% by weight to 30% by weight in the ink, and the ratio of the water-soluble resin to the water-soluble organic solvent is 4: 1.
From 1: 3. In the ink composition for transfer type ink jet recording of the present invention, the content of the water-soluble resin is preferably 100% by weight or more based on the pigment and 5% by weight to 30% by weight in the ink. The ratio of the water-soluble resin to the water-soluble organic solvent is preferably from 4: 1 to 1: 3. If the content of the water-soluble resin is less than the above range, the tackiness of the ink from which the solvent has been removed on the transfer medium is insufficient, and stable transfer cannot be obtained, which is not preferable. On the other hand, if the content exceeds the above range, the viscosity of the ink increases, which is not preferable because the ink cannot be stably ejected from the nozzles. Further, when the ratio of the water-soluble resin to the water-soluble organic solvent is out of the above range, the adhesiveness of the ink on the transfer medium varies depending on the time elapsed from the ink ejection and the printing pattern. It is not preferable because stable transfer cannot be obtained. The components used in the ink composition for ink jet recording according to the present invention will be described in detail below. As the solvent, water is mainly used because of its low viscosity, excellent safety, easy handling, low cost, and no odor.
As the ink material, pure water or ultrapure water that has undergone a purification step such as ion exchange or distillation is desirable. As the pigment, any pigment that can be uniformly dispersed by a dispersant or the like can be used. Examples of the pigments usable in the present invention include organic pigments and inorganic pigments. For example, carbon blacks such as furnace black, lamp black, acetylene black and channel black (C.I. Pigment Black 7), inorganic pigments (and metals) such as copper, iron (CI Pigment Black 11) and titanium oxide, and aniline black (CI.
And organic pigments such as CI Pigment Black 1).
Further, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 1
2 (See Aso Yellow AAA), 13, 14, 17, 24, 3
4, 35, 37, 42 (yellow iron oxide), 53, 55, 8
1, 83 (Diaso Aso Yellow HR), 95, 97, 98, 10
0, 101, 104, 108, 109, 110, 11
7, 120, 138, 153, C.I. I. Pigment Orange 5, 13, 16, 17, 3
6, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22
(Frilliant First Scarlet), 23, 31, 38, 48: 2
(Powermantlet 2B (Ba)), 48: 2 (Powermantlet 2B (C)
a)), 48: 3 (power mantlet 2B (Sr)), 48: 4 (power mantlet 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1
(Furyant Carmine 6B), 60: 1, 63: 1, 63: 2, 64:
1, 81 (Rotamin 6G lake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Catmium let), 112, 114, 122 (Kinakuri masenta), 12
3, 146, 149, 166, 168, 170, 17
2, 177, 178, 179, 185, 190, 19
3, 209, 219, C.I. I. Pigment Violet 1 (Rota Min Lake), 3,
5: 1, 16, 19 (Quinacritonlet), 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue
R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 1
5: 4, 15: 6 (phthalocyanine pure E), 16, 17: 1, 5
6, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 1
7, 18, 36, etc. can be used. According to the embodiment of the present invention, among these pigments, those having good affinity for water are preferably used. The amount of addition is preferably 0.5 to 30% by weight, more preferably 1.0 to 12% by weight. Although the particle diameter can be used from 25 μm or less, it is preferable to use a pigment comprising particles having an average particle diameter of 1 μm or less, more preferably 0.5 μm or less. In order to uniformly disperse these pigments, if necessary, a dispersant is added to the pigment in an amount of 0.5 to 200 wt.
%, More preferably 1 to 50 wt.
%, Particularly preferably 10 to 30% by weight, and it is desirable that they are further dispersed by a ball mill or the like. Preferred examples of the dispersant for dispersing the pigment used in the ink of the present invention include proteins such as glue, gelatin, casein, albumin; natural rubbers such as gum arabic and tragacanth; glucosides such as savonin. Alginic acid and propylene glycol alginate, triethanolamine alginate;
Alginic acid derivatives such as ammonium alginate; cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxyethylcellulose; acrylic polymers such as polyacrylic acid and styrene-acrylic acid; and salts thereof; Examples include nonionic surfactants such as ethylene alkyl ethers and anionic surfactants such as naphthalenesulfonic acid formalin condensate. The water-soluble resin used in the ink of the present invention becomes water-soluble by being neutralized by an alkali agent. Preferred examples thereof include alkyl acrylate- (meth) acrylic acid. , Alkyl acrylate-alkyl (meth) acrylate- (meth) acrylic acid, alkyl acrylate-styrene- (meth) acrylic acid, alkyl acrylate-alkyl (meth) acrylate-styrene- (meth) acrylic acid, acetic acid Examples thereof include vinyl- (meth) acrylic acid and vinyl chloride- (meth) acrylic acid, and one or more kinds selected from them can be used. The alkaline agent used in the present invention is not particularly limited as long as it has an alkaline pH when converted to an aqueous solution. Preferred examples thereof include monoethanolamine, diethanolamine, triethanolamine and triethanolamine. Alkanolamines such as monoisopropanolamine, diisopropanolamine, triisopropanolamine and aminomethylpropanol, metal hydroxides such as sodium hydroxide and lithium hydroxide, other alkylamines and morpholine can be used, among which monoethanolamine etc. Is preferred from the viewpoint of the stability of the ink and the like. Examples of the water-soluble organic solvent used in the present invention include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, polyethylene glycol, and polypropylene glycol. Polyhydric alcohols are used,
Or their monoetherified, dietherified,
Esterified products, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and the like, and N-methyl-2-pyrrolidone, 1.3
-Dimethylimidazolidinone, monoethanolamine,
N, N-dimethylethanolamine, N, N-diethylethanolamine, diethanolamine, Nn-butyldiethanolamine, triisopropanolamine,
A water-soluble organic solvent such as a nitrogen-containing organic solvent such as triethanolamine can be added. If necessary, a surfactant can be used to obtain wettability between the transfer medium and the ink. As surfactants, water-soluble anionic, cationic,
One or more amphoteric or nonionic surfactants can be added. The amount of addition should be 0.5 to 10% by weight, preferably 1 to 8% by weight in order to secure appropriate wettability. In order to further improve the transferability of the ink to the recording medium, it is effective to add a sticky substance such as a saccharide. Similarly, adding a silicone surfactant, a silicone resin, or the like to improve the releasability from the transfer medium is effective in improving the transferability. Further, in order to further improve the robustness of the transferred ink image, it is effective to add a water-insoluble resin component such as a resin emulsion. In addition, if necessary, pH adjusters such as potassium dihydrogen phosphate and disodium hydrogen phosphate, fungicides,
Benzoic acid, dichlorophen, hexachlorophen, p-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid (EDTA), sodium dehydroacetate, 1,2-bezothiazolin-3-one (Proxel XLII), 3 , 4-isothiazolin-3-one and the like. For the purpose of improving the drying and fixing properties of the ink, highly volatile alcohols such as ethanol and propanol can be added in a small amount. In the ink composition of the present invention containing at least water, a water-soluble resin and a water-soluble organic solvent, it is easy to form a flexible continuous film even at a low temperature, and the water-soluble resin has a property that tack tends to remain. By containing a water-soluble organic solvent with low volatility and good affinity with water-soluble resin,
When moisture in the ink image on the transfer medium is removed, uniform adhesiveness can be obtained regardless of the elapsed time after ink ejection or the print pattern. As a result, stable transfer of the ink image on the transfer medium to the recording medium without residual transfer or image deformation becomes possible. The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The production of the ink composition for transfer type ink jet recording according to the present invention comprises a first step of producing a pigment dispersion containing a pigment and a water-soluble resin as main components, and adding a water-soluble organic compound to the obtained pigment dispersion. This was performed in two steps of a second step in which a solvent, water and the like were added. However, the present invention is not limited to this, and the ink composition may be manufactured in one step.
The ink composition may be manufactured through the above steps. Table 1 shows the composition of the pigment dispersion produced in the first step. [Table 1] The production of the pigment dispersion in the first step was carried out according to the following procedure, but is not limited thereto. First, a coloring agent, a dispersant, and other components are
Mix and disperse with an appropriate dispersing machine (for example, ball mill, sand mill, attritor, roll mill, agitator mill, Henshal mixer, colloid mill, jet mill, ong mill, ultrasonic homogenizer, etc.). Thereafter, it is preferable to carry out filtration (preferably filtration under reduced pressure or pressure using a metal filter, a membrane filter or the like) or centrifugation in order to remove coarse particles and foreign substances which cause clogging. Next, Table 2 shows examples of the ink composition produced in the second step using the pigment dispersion produced in the first step. [Table 2] The production of the ink composition in the second step was performed according to the following procedure, but is not limited thereto. A water-soluble organic solvent is added to the pigment dispersion obtained in the first step, and the mixture is further stirred and thoroughly mixed. At this time, a water-soluble resin may be further added. The remaining water and, if necessary, additives such as a resin emulsion, a saccharide, a surfactant, and a preservative are added, and the mixture is stirred until it is uniformly mixed. The ink was filtered or centrifuged in the same manner as in the first step to remove dust and coarse particles to obtain a recording ink. Finally, performing the filtration operation once more is effective in preventing the contamination of impurities. Table 3 shows comparative examples of the ink compositions. [Table 3] Further, differences between the comparative examples and the examples are shown below. Inks Comparative Examples 1 and 2 Inks having a water-soluble resin content of less than 100 wt% with respect to the pigment were prepared in the same manner as in the Examples to obtain inks. Ink Comparative Example 3 An ink composition having a water-soluble resin content of less than 5 wt% was prepared in the same manner as in the example, to obtain an ink. Ink Comparative Example 4 An ink composition having a water-soluble resin content of more than 30% by weight was prepared in the same manner as in the example, to obtain an ink. Comparative Ink Example 5 An ink composition containing a water-soluble organic solvent in a ratio of less than １ ／ of the water-soluble resin was prepared in the same manner as in the example, to obtain an ink. Ink Comparative Example 6 An ink composition containing a water-soluble organic solvent in a ratio exceeding 3/1 with respect to a water-soluble resin was prepared in the same manner as in the example, to obtain an ink. The pigment content (% by weight) in the inks of the Examples and Comparative Examples and the water-soluble resin content in the ink (% by weight (the amount of the water-soluble resin added in the first step was converted to the amount in the ink) Examples and Comparative Examples, and Examples and Comparative Examples in which the water-soluble resin added in the second step was added.)), The ratio of the water-soluble resin to the pigment (% by weight), and the ratio of the water-soluble resin to the organic solvent Are shown in Table 4. [Table 4] Next, a printing test was performed using each of the inks described above with a transfer type ink jet recording apparatus described below. This recording apparatus uses the same basic configuration as that of the recording apparatus disclosed in Japanese Patent Application Laid-Open No. 62-92949. FIG. 1 is a perspective view showing the structure of a transfer type ink jet recording apparatus used in an embodiment of the present invention. FIG.
Is a sectional view. An ink jet recording head 2 is arranged around a transfer drum 1 as a transfer medium from an upstream side in a rotational direction.
A backup roller 3 serving as a transfer unit is sequentially arranged. A heating unit is disposed inside the transfer drum 1 to control the surface temperature of the transfer medium. In this embodiment, the surface temperature was set to 80 ° C. The results of printing tests of the ink composition of the present invention and the ink composition of the comparative example using the above-described transfer type ink jet recording apparatus are shown below. The evaluation conditions are as follows. Longest part from discharge to transfer: 10 seconds Minimum part: 2 seconds Print pattern solid 1 dot continuous line, alternate dotted line, evaluation criteria are as follows. ：: Transfer can be performed without transfer residue and image deformation. Δ: Transfer residue and image deformation occur partially. X: Transfer residue or image deformation occurs. Based on the above evaluation conditions and criteria, the results of evaluation using a transfer type ink jet recording apparatus using the ink composition examples 1 to 9 and the ink composition comparative examples 1 to 6 are shown in Table 5. Show. [Table 5] As shown in Table 5, when the ink composition of the present invention was used, the ink image could be transferred to the recording medium without any transfer residue irrespective of the elapsed time after the ink ejection and the print pattern. On the other hand, Comparative Examples 1, 2, 3 and
In the case of using Nos. 5 and 6, the transfer efficiency differs depending on the elapsed time and the print pattern in transfer efficiency, and good transfer efficiency could not be obtained. Comparative Example 4
Indicates that the ink could not be stably ejected. The above results indicate that the ink composition of the present invention
Contains an optimal amount of a water-soluble resin and a water-soluble organic solvent that have the property of easily forming a flexible continuous film and leaving tack even at low temperatures, ensuring uniform adhesiveness regardless of the elapsed time after ink ejection or the printing pattern. Since the ink image can be formed on the transfer medium, the ink image on the transfer medium can be transferred to the recording medium without residual transfer or image deformation, which is a novel effect obtained. As described above, the ink composition for ink-jet recording of the present invention is optimally prepared from a water-soluble resin and a water-soluble organic solvent having a property of easily forming a flexible continuous film even at a low temperature and having a tackiness. By containing in an amount, by removing the solvent, the ink image on the transfer medium can be transferred to the recording medium without residual transfer or image deformation, regardless of the elapsed time after the ink ejection or the print pattern. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a configuration of a transfer type ink jet recording apparatus used for evaluating an ink composition example of an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a configuration of a transfer type ink jet recording apparatus used for evaluating an ink composition example of an example of the present invention. [Explanation of Signs] 1: transfer drum (transfer medium) 2: recording head 3: backup roller 5: ink image 6: recording paper (recording medium) 21: ink tank 50: ink image

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naomasa Matsumoto 138-1, Kokubunji, Okuninocho, Himeji-shi, Hyogo Prefecture Inside the Mikuni Pigment Co., Ltd. Dye Co., Ltd. (72) Inventor Masayo Honmaru 138-1, Kokubunji, Okunino-cho, Himeji-shi, Hyogo Pref. Ogoku Dye Co., Ltd. (56) References JP-A-5-255624 (JP, A) JP, A) JP-A-7-148917 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 B41J 2/01 B41M 5/00

Claims (1)

(57) [Claim 1] An ink composition for transfer type ink jet recording comprising at least water, a pigment, a water-soluble resin and a water-soluble organic solvent, wherein the water-soluble resin is an alkaline agent. Alkyl acrylate-alkyl (meth) acrylic acid- (meth) acrylic acid which becomes water-soluble by being neutralized, and is incorporated in an ink in an amount of 100% by weight or more and 5% to 30% by weight in the ink. Wherein the ratio of the water-soluble resin to the water-soluble organic solvent is from 4: 1 to 1: 3.