JPH05125314A - Ink for ink-jet recording - Google Patents

Abstract

PURPOSE:To provide an ink for ink-jet recording, giving a high-density print having distinct contour and free from blotting of the letter and image on any printing object, having excellent filling performance to the ink head and flow channel and enabling easy discharge of generated bubbles. CONSTITUTION:The objective ink is produced by compounding >=0.01wt.% of C.I. Direct Black 168, 1-15wt.% of glycerol, 1-5wt.% of a <=4C monohydric alcohol and 75-95wt.% of water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording ink for use in an ink jet recording apparatus for recording characters and images with liquid ink.

[0002]

2. Description of the Related Art Conventionally, as inks used in ink jet recording systems, water-based inks have been predominant in view of odor and safety, and various water-soluble dyes are used as water or a mixed solvent of water and a water-soluble organic solvent. Dissolved inks, which are dissolved and various additives are added if necessary, are currently used.
The advantages of these ink jet recordings are a direct recording, a simple process, no noise, easy colorization, high speed recording, and low running cost because plain paper can be used. It has excellent features such as high-resolution recording because it ejects minute ink droplets, and is attracting attention in the future.

[0003]

However, in the above-mentioned prior art, (1) the ink bleeds on the transfer medium, and a high-quality recorded image cannot be obtained.

(2) The rate of drying on the transferred material is slow, tailing occurs, hands are soiled, and bleeding due to color mixing occurs when color inks are superposed.

(3) Even if the bubbles generated in the recording head or in the ink flow path are ejected, they cannot be ejected, resulting in dot omission and print disorder.

There are problems such as the above.

In order to solve the above-mentioned problem (3),
For example, Japanese Unexamined Patent Publication No. 60-24957 discloses that the inside of an ink flow path is made hydrophilic, and a method of making hydrophilic by acid treatment, plasma treatment or the like is provided.
Further, Japanese Patent Publication No. 2-54784 provides a method of improving the wetness by heating a dye aqueous solution in a state of being in contact with the ink flow channel surface and adsorbing or permeating the dye in advance on the flow channel surface. .. However, since the above-mentioned hydrophilic treatment is a primary treatment and is poor in sustainability, the effect of the hydrophilic treatment in the ink flow path is lost if the inkjet recording head is left for a long time without being filled with ink, The printing stability and reliability could not be secured.

[0008] Therefore, the present invention is to solve the above-mentioned problems, and an object of the present invention is to enable printing with a sharp contour and high density without causing bleeding of characters / images on any transferred material. Another object of the present invention is to provide an ink jet recording ink which is excellent in filling the ink into the head / flow path and can easily discharge air bubbles generated in the untreated head and flow path.

[0009]

The ink for ink jet recording of the present invention is at least C.I. I. It is characterized by containing 0.01% by weight or more of direct black 168, 1 to 15% by weight of glycerin, 1 to 5% by weight of a monohydric alcohol having 4 or less carbon atoms, and 75 to 95% by weight of water. ..

[0010]

In the ink jet recording ink of the present invention, C.I. I. By utilizing the surface active property of direct black 168, the present dye is added to the ink for ink jet recording, and the head constituent member and flow path made of glass, metal (nickel, stainless steel) or plastic, photosensitive resin, etc. The wettability with the constituent members is dramatically improved, ink can be easily filled without the need to process the head and the flow path, and the generated bubbles can be easily discharged. -It is possible to ensure reliability, and by adding this dye, the ink physical properties (for example, viscosity,
Since surface tension, pH, and wettability with paper) are not reduced, high-quality printing without blurring of characters and images can be obtained.

[0011]

EXAMPLES The ink jet recording ink of the present invention will be specifically described below.

As the dye added to the ink jet recording ink of the present invention, 0.01% by weight or more of C.I. I.
Direct black 168 is an essential component, and a water-soluble dye used in conventional inks can be used as the other dye. Any other dye can be used as long as it does not generate a precipitate by adding other ink components. Can be used. For example, C.I. I. Direct Yellow 1, 8, 11, 1
2, 24, 26, 27, 28, 33, 39, 44, 5
0, 58, 85, 86, 87, 88, 89, 98, C.I.
I. Direct Red 1, 2, 4, 9, 11, 13, 1
7, 20, 23, 24, 28, 31, 33, 37, 3
9, 44, 46, 62, 63, 75, 79, 80, 8
1, 83, 84, 89, 95, 99, 113, 197,
201, 218, 220, 224, 225, 226, 2
27, 228, 229, 230, 231, C.I. I. Direct Blue 1, 2, 6, 15, 22, 25, 41, 7
1, 76, 78, 86, 87, 90, 98, 163, 1
65, 202, C.I. I. Direct Black 2, 7, 1
9, 22, 24, 32, 38, 51, 56, 63, 7
1, 74, 75, 77, 108, 154, C.I. I. Acid Yellow 1, 3, 7, 11, 17, 19, 23, 2
5, 29, 38, 44, 79, 127, 144, C.I.
I. Acid Red 1, 6, 8, 9, 13, 14, 1
8, 26, 27, 35, 37, 42, 52, 82, 8
5, 87, 89, 92, 97, 106, 111, 11
4, 115, 118, 134, 158, 186, 24
9, 254, 289, C.I. I. Acid Blue 1, 7,
9, 22, 23, 25, 29, 40, 41, 43, 4
5, 78, 80, 82, 92, 127, 249, C.I.
I. Acid Black 1, 2, 7, 24, 26, 29,
31, 44, 48, 50, 52, 94, C.I. I. Basic Yellow 1, 2, 11, 34, C.I. I. Basic Red 1, 2, 9, 12, 14, 17, 18, 37,
C. I. Basic Blue 1, 3, 5, 7, 9, 22,
24, 25, 26, 28, 29, C.I. I. Basic Black 2, 8, C.I. I. Food Black 1, 2, C.I.
I. Food Blue 2, C.I. I. Food violet 2,
Hood Red 14, C.I. I. Food Yellow 4 etc. can be used. The examples of the above dyes are particularly preferable for the ink applicable to the recording ink of the present invention, and the dyes for the ink used in the present invention are not limited to these dyes.

Solvents suitable for use in the recording ink of the present invention include 75 to 95% by weight of ion-exchanged water having Ca and Mg ions of 5 ppm or less, and 1 to 15% by weight of glycerin as a clogging inhibitor and a penetrant. As 1 with 4 or less carbon atoms
Valent alcohols, ie methanol, ethanol, n-
Propanol, iso-propanol, butanol 1-
5% by weight is an essential component, in addition, alkyl alcohols having 1 to 4 carbon atoms, ketones or keto alcohols, ethers, polyalkylene glycols, alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, Lower alkyl ether of polyhydric alcohol, N-methyl-2
-Pyrrolidone, 2-Pyrrolidone, 1-3-Dimethyl-2
-Imidazolidinone, triethanolamine and the like are used, but not limited thereto.

The basic structure of the present invention is as described above.
Conventionally known dispersants, surfactants, viscosity adjusting agents, surface tension adjusting agents, resistivity adjusting agents, pH adjusting agents (lithium hydroxide,
Sodium hydroxide, potassium hydroxide, etc.), antifungal agents, chelating agents and the like can be added as necessary.

As the physical properties of ink, the temperature during operation is 0 ° C.
The ink viscosity when set to ˜50 ° C. is required to be 30 mPa · s or less in the vicinity of the ejection nozzle in consideration of the stability of ink supply under high speed response of the head and the stability of ink droplet flight, and further higher speed. To achieve responsiveness, 1.5 to 20 mPa · s is more preferable.
The high-speed response here means a printing ability of 2 pages / minute (A4 size) or more. Also, the operating temperature is 0 ℃ to 50 ℃.
When the surface tension of the ink is set to 4,
0-60 dyne / cm is preferable, and the pH is 7
About 10 is preferable.

If desired, the ink jet recording ink of the present invention can be further dried and fixed by a heat fixing means such as hot air, a heating roll, infrared rays or the like to impart further quick drying property.

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 C. I. Direct Black 168 0.1% by weight C.I. I. Direct Black 19 2.9 wt% Glycerin 5 wt% 1.3 Dimethyl 2 imidazolidinone 2 wt% Ethanol 3 wt% Ion-exchanged water 87 wt% Example 2C. I. Direct Black 168 0.01 wt% C.I. I. Direct Black 19 2.99 wt% Glycerin 5 wt% 1.3 Dimethyl 2 imidazolidinone 2 wt% Ethanol 3 wt% Ion-exchanged water 87 wt% Ink jet printer HG-using the inks shown in Examples 1 and 2. 4000 (Seiko Epson Corporation)
Product), and the print quality and quick-drying level are commercially available PPC
Paper (manufactured by Fuji Xerox Co., Ltd., trade name "P paper": neutral paper), bond paper (manufactured by Kimberley-Clark Corporation, trade name "Neenah Bond": acid paper), recycled paper (Fuji Xerox Co., Ltd.) Made, product name "R
"Paper": neutral paper) was recorded and the following evaluations were performed.

Evaluation of print quality bleeding: Observation with a microscope at 100 times and 400 times and visual observation ◎: Dots are not bleeding along the fiber and dots are retained on the fiber ◯: There is some bleeding along the fiber Is not visually observed. △: Some bleeding is visually visible. ×: Edges are considerably bleeding and jagged. Recording density: Measurement of reflection O / D value by Macbeth densitometer Quick drying 3 seconds, 6 seconds later, 12 Rubbing the printed part with the edge of the paper after seconds ◎: No smudging after 3 seconds ○: No smudging after 6 seconds △: No smudging after 12 seconds ×: After smudging After 12 seconds The above evaluation results are shown in Table 1. Show.

[0020]

[Table 1]

The inks of Examples 1 and 2 and Examples 1 to C.I. I. The contact angle of the ink of Comparative Example 1 excluding the direct black 168 with nickel, stainless steel 304, polysulfone, and a photosensitive resin (Tokyo Ohka dry film) was measured by an automatic contact angle meter (CZ-A).
Table 2 shows the results measured by a mold, manufactured by Kyowa Interface Science Co., Ltd.

[0022]

[Table 2]

The suction pump 11 shown in FIG. 1 (the suction pump has a pressure of about -15 cmHg and a suction amount of 0.0
2 cc / s) was used to measure the time until the ink jet recording head could be completely filled, and after the ink jet recording head was left at 70 ° C. for 5 days, the suction pump 11 shown in FIG. 1 was used, Table 3 shows the results of measuring the time until the ink 14 is sucked from the nozzle 12 through the cap 13 and the bubbles in the head and the supply path can be completely discharged.

[0024]

[Table 3]

Table 4 shows the results of measuring the time for stable and continuous discharge.

[0026]

[Table 4]

As is clear from Table 1, Table 2, Table 3 and Table 4, the ink jet recording ink of this example provided extremely excellent results.

[0028]

As described above, according to the ink jet recording ink of the present invention, at least C.I. I. By containing 0.01% by weight or more of Direct Black 168, 1 to 15% by weight of glycerin, 1 to 5% by weight of a monohydric alcohol having 4 or less carbon atoms, and 75 to 95% by weight of water, it is possible to prevent This has the effect of preventing bleeding of characters and images on the transfer body and enabling high density printing with clear contours.

Further, the affinity of the ink itself with the inside of the head and the flow path facilitates the initial filling of the ink, and the generated bubbles can be easily discharged without any treatment. Can be simplified, the cost of the recording apparatus can be reduced, and the ink consumed for discharging bubbles can be significantly saved.

Further, since transportation and storage can be performed with the inside of the flow channel being empty, there is an effect that the transportation cost can be reduced.

Further, the ink jet recording ink of the present invention enables an ink jet printer which is small in size, low in price, high in printing quality, long-term reliability, and excellent in ejection stability, and has a great effect.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an inkjet recording apparatus.

[Explanation of symbols]

 11-Suction pump 12-Nozzle 13-Cap 14-Ink 15-Head and supply path

Claims (1)

[Claims] 1. An inkjet recording ink for recording characters and images with a liquid ink, comprising at least C.I. I. It is characterized by containing 0.01% by weight or more of direct black 168, 1 to 15% by weight of glycerin, 1 to 5% by weight of a monohydric alcohol having 4 or less carbon atoms, and 75 to 95% by weight of water. Inkjet recording ink.