JPS58225171A - Yellow ink for jet printer - Google Patents

Abstract

PURPOSE:The titled ink, containing C.I. Acid Yellow 23, C.I. Direct Yellow 50, etc. as a water-soluble yellow dye and a specific amount of a wetting agent, and having a hue of good process color adaptability and improved solubility, water and light resistance. CONSTITUTION:A yellow ink containing 0.5-10wt% one of C.I. Acid Yellow 23, C.I. Direct Yellow 50, C.I. Direct Yellow 86 and C.I. Direct Yellow 142 as a water-soluble yellow dye, 5.0-70wt% wetting agent, e.g. triethylene glycol, and water as a solvent. Preferably, the content of inorganic impurities caused by the above-mentioned yellow dye is reduced to 0.5wt% or less. EFFECT:Good color reproducibility is imparted by the use thereof with a cyan or magenta ink for jet printers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a yellow ink for jet printers, and more particularly to a yellow ink for jet printers that can be used as a process color and has excellent water resistance and light resistance.

The jet printing method is a method in which ink is ejected through a fine nozzle orifice to form particles, and the ink particles are printed on a recording medium such as paper or paper by controlling the ink particles according to an input signal. It has the advantage of low noise, and because it uses minute particles, it not only has high resolution but also can be easily colored.

Therefore, the use of process color inks to produce hard copies of color images is being considered.

Process colors are three primary colors θ that can reproduce many colors, and in subtractive color mixing, they refer to five colors: cyan, magenta, and yellow. If a color that deviates from the kernel color is used as a primary color, good color reproduction will not be possible. These 3
They cannot be obtained by mixing Genshokusha colors, so in order to make process color inks, it is necessary to use dyes with these tones from the beginning. In order to be a process color, the chromaticity coordinate values of the dye must be within a certain range, but this point has not been given sufficient consideration in the past1. In this case, the color reproducibility was insufficient.

Also, when considering the recording quality of multicolor printed matter drawn using process color inks, it is desirable that the three color inks have equally excellent water resistance and light resistance, but conventional yellow ink for jet printers is water resistant. It had the disadvantage of low color stability and light resistance, and easy discoloration. In addition, because conventional yellow ink for jet printers does not sufficiently remove inorganic impurities in the dye, the solution stability of the dye decreases due to drying, which eventually causes nozzle clogging, resulting in long-term stability. It was interfering with printing.

The present invention uses a dye that has a hue that is well compatible with process colors and has excellent solubility, water resistance, and light resistance as a dye for yellow ink for jet printers, and furthermore, the yellow dye in the ink is purified by dye purification. It is characterized by a reduced content of inorganic impurities caused by There is a yellow ink available.

That is, to summarize the present invention, the present invention provides a yellow ink for a jet printer whose main components are a water-soluble yellow dye, a wetting agent, and water. Engineering, Acid Yellow 23.0. Engineering, Direct Yellow 50, C0
0.5 to 10 weight of any one of Direct Yellow 86, C9 Engineering, and Direct Yellow 142: tl,
The present invention relates to a yellow ink for JetP'1 link, characterized in that it contains 5.0 to 70% by weight of a wet abrasive agent.

The yellow ink for jet printers of the present invention includes yellow dye,
The main component is a wetting agent, water, and also contains a fungicide, a chelating agent, a pH adjuster, etc. depending on the heart IFK.1 Hereinafter, a detailed explanation will be given focusing on the yellow dye.

The chromaticity coordinates of a yellow dye that can be used as a process color are shown in the accompanying drawing. That is, the attached drawing is a chromaticity diagram showing the positions of water-soluble yellow dyes used in Examples and Comparative Examples of the present invention. In the drawing, X and y are chromaticity coordinate axes, C is a standard light source, 1 is C0, acid yellow 25.2 ke O
,X, Direct Yellow 50.3 is 0. Engineering, Direct Yellow 86.4 Kema O, 1, Direct Yellow 1
42.5 indicates C9■, Food Yellow 3.6 indicates C9 work, and Direct Yellow 87.

The chromaticity coordinates of a yellow dye that can be used as a process color must be in the vicinity of the broken line (yellow hue line) in the chromaticity diagram shown. Furthermore, since color mixing using process inks is subtractive color mixing, color saturation generally decreases due to color mixing. Therefore, it is necessary to use a dye with high chroma as a process ink, and a dye with chromaticity coordinate values as close as possible to the spectral locus in the chromaticity diagram must be selected11. As a result of examining a large number of yellow dyes, we found that C9, Acid Yellow 23, C0, Direct Yellow 50, C11, Direct Yellow 86, C0■, and Direct Yellow 142 have the chromaticity coordinates as shown in the drawing. It is located sufficiently close to both the hue line and spectral locus of yellow, making it an excellent choice for process colors (for hue and chromaticity coordinates, see J.
(see Z-8701, Z-8721), and also found that it has other properties as well.

Printing quality such as water resistance and light resistance of ink prints depends on the properties of the dye.In order to obtain ink with excellent printing quality, dyes with high water resistance and light resistance are required. It is necessary to use The above four dyes have extremely excellent light resistance and water resistance among water-soluble dyes.

Furthermore, jet printer ink has a diameter of 20 to 100μ.
Since it is required that the dye can be stably ejected for a longer period of time than the fine nozzle orifice of ζ, the dye used in ζ must have sufficient dissolution stability.

The four commercially available dyes contain 50% inorganic impurities as impurities.
Although it contains about 100% of the dye, the water solubility of the dye itself is extremely high, so even if a highly concentrated aqueous solution is prepared, it will not cause dissolution instability such as gelation of the solution and dye precipitation, which is usually seen with other reprint dyes. does not occur. Therefore, the four dyes mentioned above can be used in jet printer inks without any particular purification.
It has excellent dissolution stability.

However, C2 work, Acid Yellow 23, C1 work, Direct Ye a-so, a, ■, Direct Yellow 86 and C9! In order to further improve the dissolution stability of Direct Yellow 142, it is effective to reduce the amount of dye-based inorganic impurities that coexist with the dye in the solution, and it is necessary to purify the dye when preparing the ink. You need to do it enough. In particular, the amount of the inorganic impurity in the solution is reduced to 15
The solubility stability of the four dyes is significantly improved when the weight is reduced to less than -. For purification, a recrystallization method, a reprecipitation method, an ultrafiltration method, etc. can be used.

There are various types of inkjet printers: charge control type, on-demand type, and electrostatic type, and the physical properties required for the ink are also different.

The yellow ink cane of the present invention can be applied to any method by adjusting the composition and imparting necessary physical properties such as viscosity, surface tension, and electrical conductivity.

For example, the physical properties of ink used in a charge control type jet printer include a viscosity of 2.5 mPa*8 or less at 25°C;
Surface tension 40 dyn/cm or more, specific conductivity 1-1
0 mB/em), it is necessary to select a composition that satisfies these issues.

The dye concentration in the ink is selected based on a balance between L1 print density and dissolution stability, and is suitably 0.5 to 10%. (If the weight is less than 15, the print density will be insufficient, and the weight will be less than 10.
When the amount exceeds % by weight, the dissolution stability decreases.
1. Water is used as the solvent in the present invention. 2. By using water, it is possible to impart sufficient electrical conductivity to the ink for use in jet printers without the presence of any extra electrolyte other than the dye. Further, it is preferable to use distilled water in order to avoid insolubilization of the dye due to calcium ions and the like contained in water.

The abrasive agent is added to prevent ink from drying at the nozzle orifice. In the present invention, low molecular weight polyhydric alcohols such as triethylene glycol and tetraethylene glycol, formamide, pyrrolidones, and the like can be used as moisturizing agents. These are preferably in the range of 5.0 to 70 weights depending on the material used, S, O weight! If it is less than -, hygroscopicity is insufficient and 70
If the weight exceeds 1', the viscosity of the ink becomes too high and stable jetting becomes impossible.

The antifungal agent is added as necessary for the purpose of preventing clogging due to the growth of mold in the nozzle orifice. In the present invention, commonly known antifungal agents such as dioxin and sodium omazine can be used. α in the ink
It is preferable to add 1 to α5 weights. If it is less than 0.1 weight, the long-term antifungal ability will be insufficient, and if it exceeds 155 weight, it will reduce the dissolution stability of the dye, which is not preferable.

A chelating agent is added as necessary to prevent insolubilization of the dye due to calcium ions or the like mixed into the ink.

As the chelating agent in the present invention, well-known water-soluble chelating reagents such as ethylenediaminetetraacetic acid disodium salt (ET) TA) can be used, and f105-0
It is preferable to add about two layers.

Furthermore, it is useful to add a basic substance to the ink of the present invention to control the pH. The pH of the ink is preferably 7 to 10 in order to prevent corrosion of metal materials in contact with the ink. pH' in the present invention? A basic substance such as sodium carbonate, borax, potassium acetate, etc. can be used as a fiA moderator, but in order to maintain the dissolution stability of the dye, it is preferable that the addition amount is 1: Fio, 1 weight - or less. .

In addition, components other than those mentioned above may be added to the extent that they do not deteriorate the ink properties.

Hereinafter, the present invention will be specifically explained according to Examples, but the present invention is not limited to these.

Example 1 The following composition: 0, ■, Acid Yellow 23 (Tokyo Kasei Products): 2.
5 weight polyethylene glycol (average molecular weight: 200
) (Wako Tsumugi products): 12.9% by weight Sodium Omazine (Olin products): (
131 amount chi KDT A (Wako Tsumugi products):
11 Weight - Potassium acetate (Tokyo Kasei Products):
(107 heavy jl-distilled water:
Remaining 0 Each component was thoroughly stirred together at 60°C to completely dissolve, and left at room temperature. Then, use a Millipore filter (bore diameter 1.OIt).
A yellow ink for jet printers was prepared by passing the undissolved portion through the ink. The purity of the above dye was determined by elemental analysis, and the content of inorganic impurities was 40% by weight or more (ie, the content in the ink was 1.5% by weight or more).

The ink has a viscosity of 1.55 mPa·8 at 25°C.
1 surface tension 49.9 dyn/cm, specific conductivity &4
It showed the characteristics of 0 me/cm and pH 9.30. Furthermore, using this ink, we performed multicolor printing with cyan ink and magenta ink using a charge control type jet printer consisting of five nozzles with an orifice diameter of 50 pm. Ash, the ink 1
During the 600-hour printing test, no nozzle clogging occurred even once, and extremely good printing was obtained. However, after 600 hours, some disturbances occurred in the printed matter (monochrome prints made with this ink (1,51MX 1.5cm solid color))
Water resistance and light resistance tests were conducted according to JI Japanese Standards J Engineering 8L-0.
85! As a result of evaluation according to S and L-0842, both were given a rating of 4 or higher, and the water resistance and light resistance were good. Furthermore, a similar test was conducted on mixed-color printed matter (i), and the color difference between the samples before and after the test was determined using a direct reading colorimeter color difference computer (manufactured by Suga Test Instruments Co., Ltd.).As a result, the color difference was 5 or less, and almost no discoloration was observed.

Examples 2 to 4 In the same manner as in Example 1, water-soluble yellow dye-), wetting agent (1)), fungicide (e), chelating agent 01), II
A yellow ink for jet printers was prepared by blending 11111 moderator (e) and solvent (f) in the following composition.

Composition of Example 2 (at O, 1, Direct Yellow 50 (Sumitomo Chemicals) purified twice by recrystallization with a 1:1 mixed solvent of water and ethanol: 50% polyethylene glycol (average molecular weight 301J) )
(Wako Tsumugi products): 157 heavy duty electrical equipment) Dioxin (Thibaudan products): 0.4 car Jlchi (dl Ft DTA (Wako Tsumugi products): 0.0
5% by weight (θ) IJum (Tokyo Kasei Products):
O, [+1% by weight (f) Distilled water: Remaining composition of Example 5 (a) Purified product of O, L Direct Yellow 86 (Nippon Kazai Products) recrystallized twice in a 1:1 water-ethanol mixed solvent: 2 .6tE, WAS...) Polyethylene glycol (average molecular weight 200) (Wakyu Junyaku product): 1aO weight i% (0) Sodium omazine (Olin product): 0.24 weight 11% @) l! DTA (Wako Tsumugi products): [L1
Heavy Mch (e) Sodium carbonate (Tokyo Kasei Products): α11mN
(f) Distilled water: Remaining composition of Example 4 (a) +', 1. Direct Yellow 142 (Sumitomo Chemical) 3 with water-ethanol 2:1 mixed solvent
Re-recrystallized purified product 2 500 weight (1)) Polyethylene glycol (average molecular weight 200)
(Wako Tsumugi product): 12.7 weight 1I- (0) Sodium omazine (Orlin product): IIL 3% by weight @) II! DTA (Wako Tsumugi products): (
107% by weight (e) pHlfJ! 4 Moderation agent: 0% by weight (
f) Distilled water: Remaining composition of Example 5 (a) Purified product of O, K, Acid Yellow 23 (Tokyo Kasei Products), recrystallized twice with a 1:1 water-ethanol mixed solvent: 25 Juto'chi (b) ) Polyethylene glycol (average molecular weight 200) (
Wako Tsumugi Pharmaceutical Products]: 12.91i Ch(Q) Sodium Omazine (Olin Products): α25% by weight (product): 0.07% by weight (f) Distilled water: remainder The viscosity, surface tension, specific conductivity, and pi value of the obtained ink are as shown in Table 1 below (measurement temperature = 25°C).

In addition, elemental analysis of the purified dyes used in Examples 2 to 5 revealed that one company contained inorganic impurities;
The percentages were 10%, 15%, and 20%. Therefore, the content of inorganic impurities originating from the dye contained in the ink is
The values shown in Table 1 are 0.5 weight or less in all examples.

Table 1 Multicolor printing was performed using the ink in the same manner as in Example 1, and the color reproducibility as a process ink was good.
Further, no nozzle clogging occurred during the 600-hour printing test, and extremely good printing was obtained even after 1,000 hours.

Example 1 regarding the water resistance and light resistance of the ink monochrome printed matter
A similar test was conducted, and a rating of 4 or higher was obtained in all cases6.
The same test as in Example 1 was conducted on the mixed color printed matter obtained using the ink, but no discoloration was observed before and after the test.

Comparative Examples 1 to 5 Yellow inks for jet printers were prepared using the same composition and method as in Example 1 except for dye (a) t-.

Composition of Comparative Example 1 (a) Water-ethanol 2:1 recrystallized purified product of O, K, Food Yellow 3 (Tokyo Kasei Products): 2.5iFfi4% Same as Example 1 of other company.

Composition of Comparative Example 2 (a) Water-ethanol 1:1 recrystallization of O, Engineering, Direct Yellow 87 (Nippon Kayaku products) Nl11! Things: 2,
5% by weight.Others are the same as in Example 1.

Composition of Comparative Example 3 (a) O, 1, Direct Yellow 87 (Nippon Kayaku product): 2.5 Jukenchi and others are the same as in Example 1.

The resulting ink could be printed using a prototype jet printer that controlled the amount of charge. Table 2 shows the evaluation results of the color reproducibility, water resistance, light resistance, and long-term jetting stability of the printed matter over a period of 100 to 600 hours.

Table 2 As explained in detail above, the yellow ink for jet printers obtained by the present invention uses 4y, which has high water resistance, light resistance, and water solubility as a dye, and has excellent hue and saturation.
Because a limited number of dyes are used, the resulting ink has excellent water resistance, light resistance, and jetting stability, and has good power and negative reproduction when used in combination with cyan and magenta jet printer inks. Give sex. Further, by refining the dye, the dissolution stability of the ink is further improved, and there is an advantage that high jetting stability can be obtained without clogging or the like in the nozzle even during long-term use.

[Brief explanation of drawings]

The drawing is a chromaticity diagram showing the positions of water-soluble yellow dyes used in Examples and Comparative Examples of the present invention. Patent applicant Japanese Army G4 Public Corporation Agent Dainippon Ink & Chemicals Co., Ltd.
Continued from page 1 0 Inventor: Hiroshi Fukutomi, Dainippon Ink & Chemicals Co., Ltd., 3-35-58 Sakashita, Itabashi-ku, Tokyo 0 Inventor: Hideo Okubo 3, Sakashita, Itabashi-ku, Tokyo No. 35-58 Dainippon Ink & Chemicals Co., Ltd. @ Applicant Dainippon Ink & Chemicals Co., Ltd. 3-35-58 Sakashita, Itabashi-ku, Tokyo Procedural amendment (method) % formula % 1. Indication of the case Showa 1957 Patent Application No. 1075?55
No. 2, Title of the invention: Yellow ink for jet printers 3
, Relationship with the case of the person making the amendment Patent applicant address 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo
Name (422) Shinfuji, Representative of Nippon Telegraph and Telephone Public Corporation
Tsuneishi Shinbashi Chuo Building No. 502 Telephone (4!+7)-3467 September 9, 1982 (shipment date September 28, 1981) 6
, Subject of amendment Full text of the specification

Claims (1)

[Scope of Claims] 1. A yellow ink for a jet printer whose main components are a water-soluble yellow dye, a wetting agent, and water, wherein the yellow dye contains 0. engineering, acid yellow 23, C0 engineering, direct yellow so, o, i, direct yellow 86 and O
,
A yellow ink for a jet printer, characterized in that it contains ~10 parts by weight and a wetting agent of 50 to 70 parts by weight. 2. In a yellow ink for jet printers whose main components are a water-soluble yellow dye, a wetting agent, and water, as the yellow dye,
0. Engineering, Acid Ye 4-23,0,1, Direct Yellow 50.0. engineering, direct ie 0-86 and C1
0.5 of any one of Direct Yellow 142
A yellow ink for a jet printer, comprising 5.0 to 70% by weight of a wetting agent of ~10% by weight, and a content of inorganic impurities derived from the yellow dye of (15% by weight or less).