JPH09151344A - Inkjet recording liquid and inkjet recording apparatus - Google Patents

Abstract

(57) [Abstract] [Problem] Water resistance and light resistance are better than those of dye-based inks.
It provides printing with a hue more preferable than pigment-based ink (wide color reproduction range) and higher reliability than pigment-based ink. A pigment having a dye adsorbed thereon is dispersed in water and / or a water-soluble organic solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording ink.

[0002]

2. Description of the Related Art Ink jet recording methods include various ink (recording liquid) ejection methods, for example, an electrostatic suction method, a method of heating ink to foam it, and utilizing the pressure thereof. Recording is performed by generating and flying small ink droplets by a method such as mechanical vibration or displacement, and attaching some or all of them to a recording medium such as paper, but noise is generated. It is attracting attention as a recording method that can perform high-speed printing and multicolor printing without any problems.

Most conventional inks for ink jet recording have a water-soluble dye as a recording agent and a liquid medium as main components.
Many were poor in water resistance and light resistance.

[0004]

Recently, in order to solve these problems, an ink in which a pigment is dispersed as a coloring material has been developed. However, most inkjet recording inks that use pigments are black, and few are compatible with color inks. In addition, even if it is possible to cope with the problem, the color is considerably dull, and in many cases, color printing having a considerably narrow color reproduction range is inevitably performed as compared with a dye-based ink that is rich in color.

Further, since the ink using the pigment has poor pigment dispersion stability, the physical properties of the ink change due to the aggregation and sedimentation of the pigment and the pigment adheres to the wall surface of the ink ejection nozzle, resulting in an ink-like flying state. There is a problem that not only stable ink ejection cannot be performed due to the change, but also ejection nozzle clogging occurs. The present invention is to solve the above problems, and its purpose is to print with better water resistance and light resistance than dye-based inks and with a hue that is preferable to pigment-based inks (wide color reproduction range). Another object of the present invention is to provide an ink for an inkjet recording apparatus, which is characterized by increasing the reliability of the ink, and an inkjet recording apparatus using the same.

[0006]

The present invention has been proposed to achieve the above object, and is characterized in that a pigment having a dye adsorbed thereon is dispersed in water and / or a water-soluble organic solvent. An ink for an inkjet recording apparatus and an inkjet recording apparatus using the same. The preferred embodiments are as follows.

(1) The dye is a water-soluble dye. (2) The pigment is white. (3) The colors of the dye and the pigment are similar colors. (4) The dye is an acid dye, a basic dye or a direct dye, and the pigment at that time is an extender pigment.

(5) The dye is an acid dye, a basic dye or a direct dye, and the pigment at that time is a dyeing lake pigment using the dye. (6) The dye is a reactive dye, and the pigment at that time is an organic pigment. (7) The dye is a direct dye and the pigment is carbon black.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Conventional ink jet recording inks are mainly composed of a coloring material, water, and a water-soluble organic solvent. The coloring material is the color, stability, and safety of the ink. Therefore, dyes (desirably, direct dyes or acid dyes, reactive dyes) are mainly used. As the organic solvent, a polyhydric alcohol, a nitrogen heterocyclic compound or the like is used as a wetting agent in order to prevent clogging in the nozzle of the ink, and in addition to this, a surface active agent for adjusting the physical properties of the ink is used. Agents and water-soluble resins are added.

As the dyes, there are water-soluble dyes such as direct dyes, acid dyes, basic dyes, and reactive dyes. By adsorbing these to pigments, it is possible to realize bright printing. The dispersion stability of the pigment in water and the water-soluble organic solvent can be increased. Further, as the pigment, there are extender pigments, dyeing lake pigments, organic pigments, carbon black and the like, and when printing is performed with an ink in which these are dispersed, printing excellent in water resistance and light resistance can be performed.

The mass ratio of the dye adsorbed to the pigment is 1: 0.01 or more, preferably 1: 0.05 or more.
Further, the pigment is used in the ink in an amount of 0.5 to 1 in consideration of the color density of the ink and the prevention of clogging of the ink ejection nozzle.
0% by weight, preferably 1 to 5% by weight. The following can be given as a typical method of adsorption. That is, usually, on the surface of the pigment, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phenolic hydroxyl group, a carbonyl group and the like are produced depending on the pigment. The above functional groups are activated by adjusting the temperature, pH, etc., and some of the functional groups of the dye (that is, if the pigment is an acidic functional group, the dye is a basic functional group and vice versa). However, the dye can be adsorbed on the surface of the pigment by reacting with the dye.

Further, as the water-soluble organic solvent, specifically, monohydric alcohols such as methanol, ethanol, (normal) propyl alcohol and isopropyl alcohol, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol and diethylene glycol are used. Dihydric alcohols such as triethylene glycol, trihydric alcohols such as glycerin, polyalkylene glycols such as polyethylene glycol and polybutylene glycol, N-methyl-2-pyrrolidone, 1,3
Examples thereof include nitrogen-containing heterocyclic compounds such as dimethyl-2-imidazolidinone and lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether.

As a dispersing means, a general pigment dispersing machine such as a ball mill, a roll mill, a sand mill, an attritor or the like can be used. Furthermore, the ink of the present invention contains various anionic, cationic, and nonionic surface active agents for the purposes of viscosity adjustment, surface tension adjustment, pH adjustment, conductivity adjustment, antifungal, antiseptic, metal salt precipitation prevention, etc. Agent, polyvinyl alcohol, water-soluble resin such as cellulose, sodium hydroxide, lithium hydroxide, ethylenediaminetetraacetic acid-2-sodium (ED
TA) can be used as an additive.

[0014]

EXAMPLES The present invention will be described below with reference to Examples, but these Examples specifically explain the present invention.
The embodiment is not limited to this. FIG.
Shows an example of a recording apparatus for realizing the present invention, which is a serial type color inkjet printer.
This apparatus has four types of inks of yellow, magenta, cyan, and black, and each ink is held in the ink cartridge 1. This ink is supplied to the recording head 2 having means (for example, a piezoelectric element, a heating element, a sound wave generator, etc.) for ejecting ink droplets onto the recording sheet 3,
By the action of the means, it is ejected onto the recording paper to form dots. A dot pattern can be formed on the recording paper by the ejection timing of the ink droplets, the scan A of the head, and the scan B of the recording paper perpendicular to this scan, and arbitrary characters or figures can be recorded. Further, the color intermediate color can be expressed by appropriately superimposing ink dots of each color of yellow, magenta, and cyan. That is, red can be represented by overlapping magenta and yellow, blue by magenta and cyan, and green by overlapping yellow and cyan.

In the present invention, a color ink having the following composition was produced. [Composition 1] Yellow ink (Y) extender pigment (aluminum hydroxide) 5% by weight C.I. I. Acid Yellow 23 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual magenta ink (M) extender pigment (aluminum hydroxide) 5% by weight C.I. I. Acid Red 259 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual cyan ink (C) extender pigment (aluminum hydroxide) 5% by weight C.I. I. Acid blue 9 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual black ink (K) Carbon black 5% by weight C.I. I. Direct Black 199 0.5% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual inks were prepared as follows.

In the above composition, a dye (Y: C.I. Acid Yellow 23, M: C. I. Acid Red 259, C: C. I. Acid Blue) is added to a dispersion medium in which pure water is mixed with diethylene glycol and polyethylene glycol. 9,
K: C.I. I. Direct Black 199) was added to each, and the mixture was heated and stirred at 60 ° C. for 20 minutes to be dissolved. Next, a surfactant and a pigment (Y, M, C: extender pigment, K: carbon black) are added little by little while adjusting temperature, pH, etc., and the functional group of the dye and the functional group of the surfactant and the pigment are added. The groups were reacted to adsorb the dye onto the pigment.

At this time, the adsorption state of the dye on the pigment was investigated by using thin layer chromatography (TLC) as follows. The above mixed solution is spotted on a developing phase (reverse phase TLC) and is developed with a developing solvent containing 10% water and 90% acetonitrile, and the moving state of the coloring material (if the dye alone remains, the developing solvent develops). As you do, the colorants move, but
When the dye is adsorbed on the pigment, the coloring material remains at the spot origin. )investigated. That is, the mixed solution in the above reaction was subjected to a TLC test at any time, and heated and stirred until the coloring material did not move from the origin to adsorb the dye to the pigment.

The resulting mixture was ball milled to 10
Mill and disperse for hours. The obtained dispersion liquid was filtered through a membrane filter having a pore size of 50 μm to obtain an ink.
Of the above inks, the dyes are not limited to acid dyes and direct dyes, but basic dyes (CI basic yellow 2, CI basic red 13, CI basic blue 9) with good color development are used. May be. [Composition 2] Yellow ink dyed lake pigment (CI Pigment Yellow 115) 5% by weight C.I. I. Acid Yellow 23 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual magenta ink dyed lake pigment (CI Pigment Red 174) 5% by weight C.I. I. Acid Red 259 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual cyan ink dye lake pigment (CI Pigment Blue 9) 5% by weight C.I. I. Acid blue 9 2% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual black ink Carbon black 5% by weight C.I. I. Direct Black 199 0.5% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual The ink preparation method was the same as in Composition 1. Also,
When dispersing the pigment, glass beads having an average particle diameter of 1 mm may be mixed and pulverized and dispersed by a sand mill for 3 hours.

Further, in the same manner, an ink was prepared with the following combination of dye and pigment. [Composition 3] Yellow ink azo pigment (CI Pigment Yellow 3) 5% by weight C.I. I. Reactive Yellow 2 2 wt% Magenta Ink Azo Pigment (CI Pigment Red 23) 5 wt% C.I. I. Reactive Red 3 2 wt% Cyan ink Phthalocyanine pigment (CI Pigment Blue 16) 5 wt% C.I. I. Reactive Blue 22% by weight Inks of composition 1 to composition 3 were printed using the color inkjet printer, and the hue, water resistance, light resistance and nozzle clogging of the printed sample were investigated.

The following dye-based inks and pigment-based inks were evaluated as comparative inks. [Comparative 1] (Dye-based ink) Yellow ink C.I. I. Acid Yellow 23 2% by weight Diethylene glycol 10% by weight Nonionic surfactant 2% by weight Pure water Residual magenta ink C.I. I. Acid Red 259 2% by weight Diethylene glycol 10% by weight Nonionic surfactant 2% by weight Pure water Residual cyan ink C.I. I. Acid blue 9 2% by weight Diethylene glycol 10% by weight Nonionic surfactant 2% by weight Pure water Residual black ink C.I. I. Direct Black 199 3% by weight Diethylene glycol 10% by weight Nonionic surfactant 2% by weight Pure water balance [Comparison 2] (Pigment ink) Yellow ink Azo pigment (CI Pigment Yellow 3) 5% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual magenta ink azo pigment (CI Pigment Red 23) 5% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure Water Residual cyan ink Phthalocyanine pigment (CI Pigment Blue 16) 5% by weight Diethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual black ink Carbon black 5% by weight Di Ethylene glycol 5% by weight Polyethylene glycol 5% by weight Nonionic surfactant 2% by weight Pure water Residual [Comparison 3] (Mixed ink) An ink in which the paint was not adsorbed to the organic pigment by simply mixing the composition 3 was prepared. Then, it was set to Comparative 3.

The evaluation results are shown in FIG. 2 and Table 1. However, for the hue, draw the graph of a ^* b ^{* in} the L ^* a ^* b ^* color system,
The areas in which yellow, magenta, cyan, red, green and blue are connected were compared. (The larger the area, the wider the color reproduction range and the better the hue). The water resistance was evaluated as x when the solid color difference after immersion in water for 1 minute was 5 or more, as Δ, and when 1 to 5 was 1 or less.

The light resistance of the blue scale 3 or lower was rated as ×, and the grades 4 to 6 were rated as Δ, and the grade 6 or higher was rated as ◯. As for the nozzle clogging property, if the nozzle is left capped in the device for 1 month and then clogged, and the nozzle is still clogged even if the nozzle recovery operation is performed, the nozzle recovery operation is performed and the nozzle recovery operation is performed. The evaluation was performed with a mark of “A”, and a mark of “B” that can be printed without the nozzle recovery operation.

[0023]

[Table 1]

[0024]

From the above results, by dispersing the dye-adsorbed pigment in water or a water-soluble organic solvent, the water resistance and light resistance are better than those of the dye-based ink, and the hue is more preferable than that of the pigment-based ink. Wide reproduction range)
Moreover, the reliability was higher than that of the pigment ink.

[Brief description of the drawings]

FIG. 1 shows an inkjet recording apparatus.

FIG. 2 is a hue evaluation diagram of ink recording.

[Explanation of symbols]

 1 ... Ink cartridge 2 ... Recording head part 3 ... Recording medium A ... Head scanning direction B ... Recording paper scanning direction

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeharu Suzuki 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Kyota Akeno, 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited ( 72) Inventor Shigeyoshi Umemiya 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Hiroo Ueda, 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (2)

[Claims] 1. An ink for an ink jet recording apparatus, wherein a pigment having a dye adsorbed thereon is dispersed in water and / or a water-soluble organic solvent. 2. An ink jet recording apparatus using an ink in which a pigment having a dye adsorbed therein is dispersed in water and / or a water-soluble organic solvent.