JPH0734017A - Ink composition for ink jet recording ink - Google Patents

Abstract

PURPOSE:To transfer the ink image obtained on the transfer medium to the recording medium without affection of the environmental temperatures and the letter patterns to be printed. CONSTITUTION:In an ink composition which comprises at least water, pigments, saccharides and resin emulsion and is used in the transferring type ink jet recording process, the resin emulsion has >=50 deg.C lowest coating film-forming temperature and addition amount of >=15% based on the total solids. As a resin component in the resin emulsion, polyacrylic esters, styrene-butadiene copolymers or the like are used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ink composition for a transfer type ink jet printer.

[0002]

2. Description of the Related Art Conventional ink jet recording ink of a type in which a recording image is written by ejecting ink droplets onto a recording medium is disclosed in Japanese Examined Patent Publication No. 62-1426 and JP-A No. 4-18.
No. 462, etc., the fixability of an ink image on a recording medium,
An ink composition example comprising water, a pigment and a water-insoluble synthetic resin emulsion for the purpose of preventing ink bleeding and flow is disclosed. Further, in Japanese Patent Laid-Open No. 3-160068, in addition to the effects of the above-mentioned conventional example, water, a pigment, and a resin emulsion are prepared which are improved in compatibility with plain paper, nozzle clogging resistance, printing robustness, and storage reliability. The minimum film formation temperature (MFT, Mini
An example of an ink composition having a mum film formation temperature of 40 ° C. or higher is disclosed.

However, with the above-mentioned conventional method, high printing quality could not be obtained with a part of recycled paper, which has been increasing in popularity in recent years.

In contrast to the above-mentioned direct printing ink jet recording method, a transfer type ink jet recording method in which an ink ejected from an ink jet head is temporarily held on a transfer medium and then transferred to the recording medium, and the ink thereof are disclosed in Japanese Patent Laid-Open No. 62-62160.
-92849 and U.S. Pat. No. 4,538,156. In this transfer type inkjet recording method, ink droplets are once ejected onto a transfer medium, most of the water in the ink droplets is evaporated here, and the concentrated ink is transferred onto a recording medium such as paper. It is possible to secure high print quality without being affected by the difference in the recording medium.However, in the ink composition of water, dye and polyhydric alcohol disclosed in the conventional example, the transferred ink image is water resistant. Therefore, it was a problem to secure water resistance of the ink image.

Therefore, Japanese Patent Publication No. 62-1426, Japanese Unexamined Patent Publication No. 18462/1992 or Japanese Unexamined Patent Publication No. 3-16006.
An ink composition containing the resin emulsion disclosed in Japanese Patent Laid-Open No. 8 is disclosed in JP-A-62-92849 and US Pat.
It was used for the transfer type inkjet recording device disclosed in the specification of 538156.

[0006]

However, with the above-mentioned ink composition, a good transfer without transfer residue or ink image deformation cannot be stably obtained regardless of the environmental temperature and the printing pattern, and a good transfer is always obtained. It was difficult to secure

The present invention solves this problem, and an object of the present invention is to remove an ink image obtained on a transfer medium from a transfer residue or a deformation of the ink image without being influenced by an environmental temperature or a print pattern. It is another object of the present invention to provide a new ink composition for inkjet recording, which enables stable transfer onto a recording medium.

[0008]

The ink composition for ink jet recording of the present invention is an ink composition for use in a transfer type ink jet recording method containing at least water, a pigment, saccharides and a resin emulsion, and the minimum composition of the resin emulsion. The film forming temperature is 50 ° C or higher, and the resin content of the resin emulsion is 15% by weight with respect to the total solid content of the ink.
The above is characterized.

According to the present invention, at least water, pigments, sugars, M
In an ink composition containing a resin emulsion having an FT of 50 ° C. or higher, the ink contains a saccharide as an adhesive component, and the solvent is removed at a temperature of the MFT or higher of the resin emulsion contained in the ink, so that the environmental temperature or the printing Since it has uniform adhesiveness regardless of the pattern and also has high mechanical strength, the ink image on the transfer medium can be transferred to the recording medium without transfer residue or image deformation.

When the MFT of the resin emulsion is less than 50 ° C., in a high temperature use environment in the summer, stable film formation with good tackiness and strength cannot be obtained, resulting in poor transfer. Further, the storage reliability of the ink itself is lowered, and the nozzles are clogged due to the film formation of the emulsion resin on the front surface of the recording head.

Further, in order to obtain a good film-forming state with good tackiness and strength at a temperature of MFT or higher, the weight ratio of the resin emulsion to the total solid content in the ink must be 15% or more, If it is less than that, adhesiveness and strength are insufficient.

Conventionally, water has been mainly used as the ink solvent 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 process such as ion exchange or distillation is desirable.

Any pigment can be used as long as it can be uniformly dispersed with a dispersant or the like.

Examples of pigments that can be used in the ink of the present invention include organic pigments and inorganic pigments.
For black, furnace black, lamp black,
Carbon black (CI Pigment Black 7) such as acetylene black and channel black, or metals such as copper, iron (CI Pigment Black 11) and titanium oxide, aniline black (CI Pigment Black) Organic pigments such as 1) are mentioned. For color, C.I. I. Pigment Yellow 1 (Fast Yellow
G), 3, 12 (this as yellow AAA), 13, 14, 17,
24, 34, 35, 37, 42 (yellow iron oxide), 53,
55, 81, 83 (This As Yellow HR), 95, 97, 9
8, 100, 101, 104, 108, 109, 11
0, 117, 120, 138, 153, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 5
1, C.I. I. Pigment Red 1, 2, 3, 5, 17,
22 (Brilliant First Scarlet), 23, 31, 38, 4
8: 2 (Permanentlet 2B (Ba)), 48: 2 (Permanentlet 2B)
(Ca)), 48: 3 (permanentlet 2B (Sr)), 48: 4 (permanentlet 2B (Mn)), 49: 1, 52: 2, 53: 1, 57:
1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 6
4: 1, 81 (Rotamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium let), 112, 114, 122 (Kinacridon magenta), 12
3, 146, 149, 166, 168, 170, 17
2, 177, 178, 179, 185, 190, 19
3, 209, 219, C.I. I. Pigmen Violet 1
(Rotamine lake), 3, 5: 1, 16, 19 (quinacridlet), 23, 38, C.I. I. Pigment Blue 1, 2,
15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E),
16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36,
Etc. can be used.

The amount added is preferably 0.5 to 30% by weight, more preferably 1.0 to 12% by weight. The particle size can be 25 μm or less, but it is preferable to use a pigment composed of particles having an average particle size of 1 μm or less, and more preferably 0.5 μm or less.

In order to uniformly disperse these pigments, if necessary, a dispersant is added in an amount of 0.5 to 200 wt.
% Can be added, and more preferably 1 to 50 wt.
%, Particularly preferably 10 to 30% by weight, and it is desirable to carry out dispersion treatment with a ball mill or the like.

A typical example of the dispersant for dispersing the pigment used in the ink of the present invention is an acrylic resin, and specific examples of such an acrylic resin include, for example, a styrene-acrylic acid copolymer and an acrylic resin. Acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid-
Acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic Examples thereof include acid-acrylic acid alkyl ester copolymers and salts thereof.

The solvent added when the dispersant is dissolved in water is, for example, 2-aminoisobutanol, triethanolamine, diethanolamine, monoethanolamine, Nn-butyldiethanolamine, N,
N-dimethylethanolamine, N, N-diethylethanolamine, triisopropanolamine, morpholine, aqueous ammonia, propylene glycol, isopropanol and the like may be used as an auxiliary agent.

The resin emulsion used in the ink of the present invention has a MFT of 50 ° C. or higher, preferably 60 ° C. or higher.
Two or more kinds can be mixed and used. The amount added is required to be 15% by weight or more based on the total solid content in the ink.

As an example of the resin component of the resin emulsion,
Polyacrylic acid ester, polymethacrylic acid ester, polyethyl acrylic acid ester, styrene-butadiene copolymer, butadiene copolymer, acrylonitrile-butadiene copolymer, chloroprene copolymer, crosslinked acrylic resin, crosslinked styrene resin, fluorine Resin, vinylidene fluoride, benzoguanamine resin, phenol resin, polyolefin resin, cellulose, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, polystyrene, styrene-acrylamide copolymer, n-isobutyl acrylate, Acrylonitrile, vinyl acetate, acrylamide, silicone resin, polyvinyl acetal, polyamide, rosin resin, polyethylene, polycarbonate, vinylidene chloride resin, polyvinyl alcohol Cellulose resins, epoxy resins, vinyl acetate resins, ethylene - vinyl acetate copolymer,
Vinyl acetate-acrylic copolymer, vinyl chloride resin, polyurethane, rosin ester, polyethylene wax, montan wax, alcohol wax, synthetic oxidation wax, α-olefin-maleic anhydride copolymer, animal and plant wax such as carnauba wax, lanolin, Paraffin wax, microcrystalline wax, and the like are included, but are not limited thereto.

Further, although these resins are dried in a normal temperature environment, it is desirable that they do not form a film and form a powder or a brittle solid, which is strong when the solvent is removed at a temperature of MFT or higher. It is desirable to form a continuous film that is water resistant.

The sugars used in the ink of the present invention include glucose, diose, maltitol, triose, tetrose, pentose, hexose, heptose, octose, nonose, saccharose (sucrose), inositol, xylose, maltotriose, galactose, α. -Monosaccharides such as cyclodextrin, disaccharides, trisaccharides, tetrasaccharides, polysaccharides and their derivatives sugar alcohols, reduced derivatives such as deoxy sugars, oxidized derivatives such as aldonic acid and uronic acid, dehydrated derivatives such as glycoethene, amino sugars, Examples include sugars such as thio sugar.

These sugars are added to the ink of the present invention,
It is preferable to use the content ratio of the sugar and the resin component of the resin emulsion between 1: 4 and 4: 1. If the content of the sugar is too low, the adhesiveness will be small and transfer failure will occur, and if it is too high, printing will be performed. The water resistance of the product is reduced.

If desired, a surfactant may be used to obtain the wettability between the transfer medium and the ink. As the surfactant, water-soluble anionic, cationic,
One or more amphoteric and nonionic surfactants can be added.

The addition amount is required to be 0.5 to 10 wt%, preferably 1 to 8 wt% in order to secure appropriate wettability.

In addition, if necessary, a pH adjusting agent such as potassium dihydrogen phosphate or disodium hydrogen phosphate, an antifungal agent,
Benzoic acid, dichlorophen, hexachlorophene, p-hydroxybenzoic acid ester, ethylenediaminetetraacetic acid (EDTA), sodium dehydroacetate, 1,2-bezothiazolin-3-one (Proxel XLII), 3 for the purpose of antiseptic and rust prevention. , 4-isothiazolin-3-one and the like can be included.

A hydrophilic high-boiling point low-volatile solvent can be added to the ink of the present invention in order to impart the effects of nozzle clogging resistance, moisture retention and dispersion stability. The hydrophilic high boiling point low volatility solvent used in the present invention includes glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, etc. Polyhydric alcohols are used, or their monoethers, diethers, and esters, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether. Butyl ether etc. are used,
Others N-methyl-2-pyrrolidone, 1.3-dimethylimidazolidinone, monoethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, diethanolamine, N-n-butyldiethanolamine, triisopropanolamine, triethanol A water-soluble organic solvent such as a nitrogen-containing organic solvent such as an amine can be added within a range in which the flow of printing does not cause bleeding.

For the purpose of improving the drying property and fixing property with respect to water as the main solvent, ethanol, propanol,
Highly volatile alcohols such as can be added in a small amount.

In addition, in order to regulate MFT, DBP
(Dibutyl phthalate), DEP (diethyl phthalate), BBP (butyl phthalyl butyl glycolate) and other plasticizers are mixed with the resin, and carbe such as diethylene glycol monobutyl ether in the hydrophilic high boiling point low volatile solvent is used. Tols can be added as a film forming aid, if necessary.

[0030]

EXAMPLES The present invention will be explained in more detail by the following examples, but the present invention is not limited thereto.

Ink compositions of Examples and Comparative Examples of the present invention are shown in Table 1. In Table 1, EM is a resin emulsion, and the weight ratio of the resin emulsion to the total ink solid content was calculated excluding additives such as surfactants and preservatives. Further, the addition amounts of the pigment, resin, and saccharide are all values as solid content.

[0032]

[Table 1]

The inks of Examples and Comparative Examples were manufactured by the following procedure.

An aqueous dispersion composed of a colorant and a dispersant was dispersed by a ball mill, and it was confirmed by microscopic observation that the pigment particles were in a monodispersed state. There, a resin emulsion, a saccharide, a surfactant, and hydrophilicity were added. A high boiling point and low volatility solvent is added, and the mixture is further stirred for 30 minutes and stirred for complete homogenization. After adding additives such as preservatives and confirming complete dissolution, the dispersion was filtered through a membrane filter having a pore size of 10 μm to remove dust and coarse particles to obtain a recording ink. Finally, another filtration operation is effective in preventing the inclusion of impurities.

Next, a printing test was conducted using the above-described inks in a transfer type ink jet recording apparatus described below.

FIG. 1 is a perspective view showing the structure of a transfer type ink jet printer used in an embodiment of the present invention. Figure 2
Is a sectional view. Around the transfer drum 1, which is a transfer medium, from the upstream side in the rotation direction, the inkjet recording head 2,
Backup rollers 3, which are transfer means, are sequentially arranged. A heating unit is arranged inside the transfer drum 1 to control the surface temperature of the transfer medium. In this embodiment, the surface temperature is MFT + of the resin emulsion in the ink.
It was set to 20 ° 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 transfer type ink jet recording apparatus are shown below.

The evaluation conditions are as follows.

Environmental temperature × humidity 20 ° C. × 50% RH 40 ° C. × 50% RH Printing pattern Solid 1 dot continuous line, 1 dot every other dotted line, evaluation criteria are as follows.

◯: Transfer is possible without transfer and no image deformation. Δ: Transfer remains and image deformation partially occurs. X: Transfer residue or image deformation occurs.

Table 2 shows the results of an examination conducted by a transfer type ink jet recording apparatus using the ink compositions 1 to 3 and the ink comparative examples 1 and 2 based on the above evaluation conditions and judgment criteria.

[0042]

[Table 2]

As shown in Table 2, when the ink composition of the present invention was used, the ink image could be transferred onto the recording medium without any transfer residue regardless of the environment and the printing pattern.

On the other hand, in the case of using the ink comparative example, the transfer efficiency varied depending on the environment and the printing pattern, and the good transfer efficiency could not be obtained.

Furthermore, the ink of Comparative Example 2 caused clogging during the evaluation. In addition, the viscosity of the ink itself changed, and the storage reliability decreased.

The above results show that the ink composition of the present invention contains a pigment and a saccharide, and further, a resin emulsion having an MFT of 50 ° C. or higher is 15% by weight based on the total solid content in the ink.
By containing the above, when the solvent is removed at a temperature equal to or higher than the MFT of the resin emulsion, an ink image having high mechanical strength is formed on the transfer medium, which has uniform adhesiveness regardless of the environmental temperature and the printing pattern. Therefore, it is obtained by the novel effect that the ink image on the transfer medium can be transferred to the recording medium without transfer residue or image deformation.

[0047]

As described above, the ink composition for ink jet recording of the present invention contains a pigment and a saccharide, and further contains a resin emulsion having an MFT of 50 ° C. or higher in an amount of 15% by weight or more based on the total solid content. As a result, the ink contains a saccharide as an adhesive component, and the solvent evaporates at a temperature not lower than the MFT of the resin emulsion contained in the ink, so that the ink image on the transfer medium is formed regardless of the environmental temperature or the print pattern. It has an effect that it can be transferred to a recording medium without transfer residue or image deformation.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a transfer type inkjet recording apparatus used for evaluation of an ink composition example of an example of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a transfer type inkjet recording device used for evaluation of an ink composition example of an example of the present invention.

[Explanation of symbols]

 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naomasa Matsumoto 138-1 Kokubunji, Gokokuno-cho, Himeji-shi, Hyogo Prefecture Mikuni Pigment Co., Ltd. Mikuni Dye Co., Ltd. (72) Inventor Masayo Honmaru 138-1 Kokubunji, Gokokuno-cho, Himeji City, Hyogo Prefecture

Claims (1)

[Claims] 1. An ink composition for use in a transfer type ink jet recording method, which comprises at least water, a pigment, a saccharide and a resin emulsion, wherein the minimum film forming temperature of the resin emulsion is 50 ° C. or higher, and An ink composition for inkjet recording, wherein the resin content is 15% or more by weight ratio with respect to the total solid content of the ink.