JPH0341171A - Color printing method using inkjet recording method - Google Patents

Abstract

PURPOSE:To solvent the problem of incompatibility of a high definition with a penetrability in a penetrable recording medium such as plain paper by printing the penetrable recording medium first with a colored water-base ink having a specified surface tension and then with another colored water-base ink having a specified surface tension higher than that of the former water-base ink. CONSTITUTION:A penetrable recording medium is printed first with a colored water-base ink having a surface tension of 30-40dyne, and then with a colored water-base ink having a surface tension of 45-73dyne. As the former ink, one contg. water, a water-sol. dye, an anti-drying agent, and a penetrant is pref.; the pref. penetrant contains at least one compd. selected from the group consisting of a compd. of formula I (wherein R<1> is H, methyl, etc.; and (n) is 1-5), a compd. of formula II (wherein R<2> is R<1>, and (m) is (n)), and an adduct of 1-5mol of ethylene or propylene oxide to 1mol of butyl alcohol. As the latter ink, one contg. water, a water-sol. dye, and an anti-drying agent is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color printing method using an inkjet recording method.

[Prior Art] Inkjet recording methods include the so-called electric field control method in which ink is ejected using electrostatic attraction; the so-called drop-on-demand method in which ink is ejected using the vibration pressure of a piezo element; The so-called bubble jet method uses the pressure generated by the formation and growth of air bubbles due to high heat to eject ink; a pump applies pressure from behind the nozzle, and at the same time high-frequency vibrations are applied using a piezo element to turn the ink into particles. Various inkjet recording methods have been proposed, such as a continuous method in which the ink droplets are then charged with a charging electrode and the charged ink droplets are further controlled with a control electrode.

In these inkjet recording systems, water-based inks that use water as the main solvent and oil-based inks that use organic solvents as the main solvent are generally used.

Images printed using water-based inks generally have poor water resistance, but since the main solvent is water, they are safe and can provide printed images of excellent quality.
Water-based inks are the mainstream inkjet recording inks.

On the other hand, water-based ink, unlike oil-based ink, has a high surface tension, so on permeable recording media, especially recording paper called plain paper, the ink's immersion IB force is small, causing roller marks caused by the paper feed roller, etc. Feathering occurs due to ink seeping in the direction of the fibers, resulting in roughness of solid images, deterioration of character quality, and in the case of color printing, bleeding caused by ink flowing between adjacent different colors. There were problems such as occurrence of

In addition, lowering the surface tension of the ink has the effect of increasing its penetrating power, but depending on the surface tension adjusting agent used, a good penetrating effect may not always be obtained, and the ink tends to foam and lack jetting stability. The problem was that Furthermore, there were other problems such as the generation of satellites due to a decrease in surface tension.

In order to solve these problems, the following proposals have been made focusing on penetrants.

JP-A No. 56-32566 proposes a method of adding diethylene glycol monobutyl ether to the ink, but sufficient penetration power is not always obtained, and if a large amount is used to increase the penetration power, This had the problem of generating an unpleasant odor. On the other hand, JP-A-55-2
9546, JP-A-56-95961, and JP-A-59-20366 propose a method of adding a nonionic surfactant or an anionic surfactant dialkyl sulfosuccinic acid to the ink. However, if a surfactant is added to the extent that a penetrating effect is obtained, printing dots will smear on the recording paper, making the image unclear, and the ink will foam more, making it difficult to achieve stable ink ejection. However, there have been problems in that the dissolution stability of the coloring material in the ink deteriorates over time.

Furthermore, Japanese Patent Laid-Open No. 56-57862 proposes adding a strong alkaline substance to the ink to dissolve fiber materials and sizing agents on the surface of the recording paper to increase the drying and fixing speed of the ink. The problem has been that, depending on the type of paper, sufficient effects cannot necessarily be obtained in increasing the drying/fixing speed or improving the print quality. Tokuko Sho 62-141
No. 88 proposes a method of adding an ethylene oxide adduct of unsubstituted or substituted phenol to ink, but the ink's permeability into plain paper was not always sufficient. Furthermore, JP-A No. 59-22972 proposes a method in which an ethylene oxide adduct of an aliphatic alcohol having a specific structure and a polyhydric alcohol derivative such as an alkyl ether of polyoxyethylene are added to the ink. However, the dissolution stability of the ink over time and its permeability against paper passing were insufficient. Japanese Patent Publication No. 1-1105
No. 77 proposes a penetrating agent consisting of a propylene oxide adduct of methanol and an alkyl ether or substituted phenyl ether of ethylene oxide or propylene oxide adduct with an adduct number of moles of 1 to 3.

[Problem to be solved by the invention]

However, although the above-mentioned ink composition has excellent permeability into plain paper and can provide high-density printing, it spreads widely in the lateral direction on the surface of plain paper, making it difficult to achieve high resolution. It is unsuitable for color printing of required characters and line drawings, and a decrease in image quality due to the generation of satellites due to the decrease in surface tension due to the use of penetrants is unavoidable.

The problem to be solved by the present invention is to substantially eliminate the contradiction between permeability and resolution for permeable recording media such as plain paper, which was not necessarily achieved with the above-mentioned permeability-improved ink compositions. An object of the present invention is to provide a color printing method using an inkjet recording method.

[Means to solve the problem]

In order to solve the above problems, the present invention aims to (1) print on a permeable recording medium using a color water-based ink with a surface tension in the range of 30 to 40 dynes, and (2) print a surface on the same recording medium. Provided is a color printing method using an inkjet recording method, characterized in that printing is performed using color aqueous ink having a tension in the range of 45 to 73 dynes.

The present inventors have conducted extensive studies regarding the above-mentioned problems.

As a result, for various problems such as bleeding and roller marks in color printing, surface tension of 30 to 40
For problems such as characters and line drawings that are solved by color inks within the dyne range, and where resolution is important,
It has been found that the above-mentioned contradiction between permeability and high resolution can be substantially resolved by printing with a color ink having a surface tension in the range of 45 to 73 dynes. At this time,
Cyan, magenta, yellow ink is used as the color ink having a surface tension in the range of 30 to 40 dynes, black ink is used as necessary, and black ink is used as the color ink having the surface tension in the range of 45 to 73 dynes. The printing method enables full-color printing with high-resolution black characters and patterns suitable for documents.

On the other hand, if the printing order of the above-mentioned color ink with low surface tension and color ink with high surface tension is reversed, the ink with high surface tension will appear on the surface of the permeable recording medium before it completely penetrates into the permeable recording medium. As a result of printing with low tension ink, the flow (bleed) of the low surface tension ink toward the high surface tension ink was noticeable, which was undesirable.

The color water-based ink having a surface tension in the range of 30 to 40 dynes contains a water-soluble dye, an anti-drying agent, and a penetrant, and the penetrant is (a) a compound represented by the following general formula (1), ( b) a compound represented by the following general formula (II); and (c) an ethylene oxide or propylene oxide adduct of butyl alcohol, which is selected from the group consisting of a compound in which the number of moles added is in the range of 1 to 5. Those containing more than one type of compound are preferred.

General formula (1) (In the formula, R1 represents a hydrogen atom, a methyl group, a methoxy group, a chlorine atom, or a bromine atom, and n represents an integer of 1 to 5.) General formula (II) 2 (In the formula, R2 represents a hydrogen atom, a methyl group, a methoxy group, a chlorine atom, or a bromine atom; Those containing a water-soluble dye and an anti-drying agent are preferred.

The water used for color water-based inks must be of a purity higher than that of ion-exchanged water in order to remove the influence of heavy metals.

The water content in the color aqueous ink is preferably 5% by weight or more from the viewpoint of dye dissolution stability.

Any water-soluble dye can be used for color water-based ink, and acid dyes, basic dyes, direct dyes, reactive dyes, disperse dyes, food colorants, etc. can be used as needed. Selectable.

Examples of acidic dyes include C, 1, Acid Black 1.2.7.16.1? , 24.26.28.31
．． 4148, 52.58.60.63.94.107.
109.112.118゜119, 121.122.1
31.155.156, C, 1, Acid Yellow 1.3.4.7.11.12.13.14.17.1B
.

19, 23.25.29.34.36.38.40.4
1.42.44゜49, 53.55.59.61.71
．． 72.76, 7B, 79.99°111, 114.
116.122.135.142.161.172;
C.I.

Acid Orange 7, 8.10.19.20.24.
2B.

33, 41.45.51.56.64, C, 1, Acid Red 1.4.6.8.13.14.15.1
8.19.21.26°27, 30.32.34.35
．． 37.40.42.44.51.52゜54, 57.
80.82.83.85.87.8B, 89.92.
94°97, 106.108.110.111.114
．． 115.119.129゜131, 133.134.
135.143.143: 1.144.152゜1
54, 155.172.176, 180.184.18
6.187.249°254, 256.289.317
．． 318, C,! , Acid Violet 7, 1
1.15.34.35.41.43.49.51゜75
; C, 1, Acid Blue 1.7.9.15.2
2゜23, 25. 27. 29. 40. 41.
43. 45. 49. 51. 53°55, 56
．． 59. 62. 78. 80. 8L 83.
90. 92. 93°102, 104. 111
．． 113. 117. 120. 124. 126
．． 138°145, 167, 171. 175.
183. 229. 234. 236. 249;
c, r, acid green 3.9.12.16.19
．． Examples include 20°25, 27.41.44; C,1, Acid Brown 4°14, etc.

Examples of basic dyes include C,1, Paysikta Black 2.8, and C,1, Paysic Yellowl.

2, 11.12.14.21.32.36; C, 1
, Paysic Orange 2.15.21.22; C,
1, Paysic Red T, 2.9.12.13.3
7, C, 1, Paysic Violet 1.3.7
．． 10.14, C, 1, Paysic Blue 1.3
．． 5.7.9.24.25.26.28.29°C,!
, Basic Green l, 4; Basic Brown 1
．． 12 etc. are mentioned.

Examples of direct dyes include C,1, Direct Black 2.4.9.11.14.1? , 19.22.27
．． 32°36, 38. 41. 48. 49. 5
1. 56. 62. 71. 74. 75°77,
78. 80. 105. 106. 107. 1
08. -112. 113°117, 132. 1
46. 154. 168. 171. 194;
C, 1, Direct Yellow 1.2.4.8.11
．． 12.24.26°27, 28. 33. 34.
39. 41. 42. 44. 48. 50.
51°58, 72. 85. 86. 87. 88
．． 98. 100. 110. 127°135, 1
41.142.144, C, I, Direct Orange 6, 8.10.26.29.41.49.51,1
02; C, I.

Direct Red L 2.4.8.9.11.13.
15°17, 20. 23. 24. 2B, 3
1. 33. 37. 39. 44. 46°47,
4B, 51. 59. 62. 63. 73.
75. 77, 80. 81°83, 84. 8
5. 87. 89. 90. 94. 95. 99
．． 101. 108°110, 145. 189.
197. 220. 224. 225. 226.
227°230, 250.254.256.257
; C, 1, Direct Violet 1.7.9.
12.35.48.51.90.94 iC, 1, Direct Blue 1.2.6.8.15.22°25,
34. 69. 70. 71. 72. 75. 7
6, 78. 80. 81°82, 83. 86.
90. 98. 106. 108. 110. 1
20. 123°158, 163. 165. 19
2. 193. 194. 195. 196. 19
9°200, 201. 202. 203. 207
．． 218. 236. 237. 239°246,
258.287: C, 1, Direct Green 1
, 6.8.2B, 33.37.63.64; C,
I, Direct Brown 16.2.6.25.2
7.44.58.95°100.101,106,11
2,173,194,195,209,210°211
etc.

Examples of reactive dyes include C,1, Reactive Black 1.3.5.6.8.12.14; C,1, Reactive Yellow 1.2.3.13.14.15.1
7; C, I.

Reactev Orange 2.5.7.16.20.24
:C, 1, Reacte Bread 6, 7.11.12.1
51? , 21.23.24.35.36.42.63
．． 66, 84.184; C, 1, Reactebu Violet 2.4.5.8.9; c, r, Reactebu Blue 2.5.7.12.13.14°15, 17.1B
, 19.20.21.25.27.2B, 37.3
8゜40, 41, C, L, Reacteve Green 5,7; C,1, Reacteve Brown L 7.16
etc.

Examples of food coloring include C,1, Food Black i, 2; C,R, Food Yellow 3.4.5
.

C, I, Hood Red 2.3.7.9.14.52.
87°92.94.102.104.105.106
;C,1,7F Hao l/7to2;C,! , 7-dob n'-1,2; C,1 hood green 2,3
etc.

Other water-soluble dyes include, for example, "Kayaset Black 009A J" and "Da Red" manufactured by Nippon Iyakusha.
Deep Black
S-6GLL J, “pyranine”; rJ manufactured by Sumitomo Chemical Co., Ltd.
rJPK-81L J, rJPK-127L J manufactured by Orient Chemical Co., Ltd.
, rJPK-139J ;C,! , 7o-L, all 7o
-L, Itoning Agent 14.22.2432
, 84.85.86.87.90.134□166, 1
67, 169°175, 176, 177, etc.

The content of water-soluble dye in color water-based ink is 0, l~
A range of 20% focus is preferable.

Anti-drying agents are used to prevent ink from solidifying due to moisture evaporation, and even when solidified, to ensure resolubility in washing water or color water-based ink, whether the ink is permeable or not. It is necessary to use 0.1% by weight or more.

Examples of anti-drying agents include glycols such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, and glycerin; glycol ethers such as ethylene glycol monomethyl ether and diethylene glycol monomethyl ether;
Examples include pyrrolidones such as N-methyl-2-pyrrolidone; alkanolamines such as triethanolamine; dimethyl sulfoxide; however, other common water-soluble organic solvents may also be used. The content of the anti-drying agent in the color aqueous ink is preferably in the range of 0.1 to 95% by weight. However, if a large amount of the anti-drying agent having a penetrating effect such as glycol ethers is used, the surface tension may be significantly increased. Therefore, when preparing water-based color inks with a surface tension in the range of 45 to 73 dynes, it is necessary to pay attention to the type and proportion of anti-drying agents used.6 Penetrants include -a interfaces. Ink is produced by various combinations of various water-soluble organic solvents that have a penetrating effect on permeable recording media such as plain paper, including activators and glycol ether-based water-soluble organic solvents such as diethylene glycol monobutyl ether. Surface tension is 30~
Any penetrant composition within the range of 40 dynes can be used without any particular restriction, but (a) a compound represented by the general formula (I), (b) a compound represented by the general formula (■), and (c) ) It is an ethylene oxide or propylene oxide adduct of butyl alcohol, and the number of moles added is 1 to 1.
Particularly preferred are penetrant m-acids containing one or more compounds selected from the group consisting of compounds in the range 5.

Penetrant compositions containing propylene oxide adducts of butyl alcohol are particularly preferred since they exhibit good penetration effects and excellent dissolution and jetting stability.

The content of the penetrant in the color aqueous ink is preferably in the range of 0 to 25% by weight.

The color aqueous ink may contain an alkali metal hydroxide, a pH adjuster such as an alkanolamine, an antibacterial/antifungal agent, a sequestering agent, a water-soluble polymer, and the like.

Color water-based ink with surface tension adjusted to the desired range is
It can be easily produced by preparing an ink with high surface tension and adding a penetrant or glycol ether to the extent that it does not affect the various physical properties of the ink.

〔Example〕

Examples will be explained below. In the Examples, "%" represents "% by weight". rEOJ is ethylene oxide, rP
OJ each represents propylene oxide.

Example 1 [Permeable ink composition example 1] Water-soluble dye 3.0% Eo 1 mole adduct of phenol 1.0% diethylene glycol-n-6°0% Butyl ether (EO 2 mole adduct of n-butanol) Water 73 ．．
7% diethylene glycol 15.0% N-
Methyl-diethanolane 1. O% ethyleneaminetetraacetic acid, 4 sodium 0.1% lium salt (EDTA
・4Na) Omazine Na (antibacterial/antifungal agent) 0.2% Water-soluble dyes include C,1, Direct Blue 86 for cyan, and C,1, Reactive Blend 18 for magenta.
4 and yellow colors are C, 1, Direct Yellow 44
were used respectively.

After mixing the above components and sufficiently dissolving them at room temperature, this solution was filtered using a 0.45 micron membrane filter to obtain color aqueous ink 1. The surface tension of each color water-based ink 1 was 37 dynes.

[Non-penetrating ink composition example 1] Water-soluble dye (c, 1, direct 3.0% blank 17
1) Water 73.
7% diethylene glycol 22.0% triethanolamine 1.0% EDTA-
4Na O, 1% Omazine Na
0.2% After mixing the above components and fully dissolving them at room temperature, the solution was filtered using a 0.45 micron membrane filter.
Black water-based ink 1 was obtained. The surface tension of black water-based ink 1 was 60 dynes.

Using each of the above color water-based inks 1 and black water-based ink, continuous jet printing was performed using a continuous jet printer designed to prevent rollers from hitting the printing surface, and stable ink jetting was observed even after 200 hours. Obtained.

In addition, when printed on commercially available copy paper, Color Ink 1 penetrated instantly, with no bleeding between different colors or feathering of dots, high dot roundness, and a smooth solid surface. The print quality was shown to be excellent. On the other hand, characters written in black ink had extremely high resolution, and complex characters with many strokes could be printed beautifully.

Example 2 [Permeable ink composition example 2] Water-soluble dye 3.0% EO 1.0% 3 mole adduct of Hensyl alcohol diethylene glycol-n -6.0% butyl ether (EO 2 mole adduct of n-butatoul) n - P OO, 3% 2 mol adduct of butyl alcohol water 53.7
% diethylene glycol 34.7% triethanolamine 1.0% EDTA・4
Na O, 1% Omazine Na
As a 0.2% water-soluble dye,
C,1, Direct Blue-199 was used for the cyan color, C,R, Acid Red 154 was used for the magenta color, and C,I, Direct Yellow 142 was used for the yellow color.

After mixing the above components and sufficiently dissolving them at room temperature, the solution was filtered using a membrane filter of 0.45ξ cm to obtain color aqueous ink 2. The surface tension of each color water-based ink 2 was 34 dynes.

(Non-penetrating ink composition example 2) Water-soluble dye (c, 1, Dyref) 3.0% Black 154) Water 53.
7% diethylene glycol 42.0% triethanolamine 1.0% EDTA-
4Na O, 1% Omazine Na
O, 2% After mixing the above components and fully dissolving them at room temperature, the volume of this solution was reduced to 0.45%.
Filtration was performed using a micron membrane filter to obtain black aqueous ink 2. The surface tension of black water-based ink 2 was 52 dynes.

Using each of the above color water-based inks 2 and black water-based ink 2, continuous jetting was performed using a drop-on-demand jet printer designed to prevent rollers from hitting the printing surface, and the ink remained stable even after 200 hours. A jet was obtained. In addition, when printed on commercially available copy paper, Color Ink 2 penetrated instantly, with no bleeding between different colors or dot feathering, high dot roundness, and a smooth solid surface. The print quality was shown to be excellent. On the other hand, characters written in black ink had extremely high resolution, and complex characters with many strokes could be printed beautifully.

Comparative Example 1 Water-soluble dye 3.0% phenol adduct with 1 mole of EO 1.0% diethylene glycol-n-6.0% butyl ether (n-butyl alcohol with 2 mole EO adduct) Water 73.
7% diethylene glycol 15.0% triethanolamine 1.0% EDTA・
4Na O, 1% Omazine Na
O,2% water-soluble dyes include C,1, Direct Blue 199 for cyan, C,1, Reactive Red 184 for magenta, C,1, Direct Yellow 142 for yellow, and C,1, Direct Yellow 142 for black. C.1 and Direct Black 171 were used, respectively.

After the above components were mixed and sufficiently melted at room temperature, the solution was filtered using a 0.45 G chron membrane filter to obtain color aqueous ink 3. The surface tension of each color water-based ink 3 was 37 dynes.

When each of the color aqueous inks described above was continuously ejected using a continuous jet printer, stable ink ejection was obtained even after 200 hours. In addition, when printing on commercially available copy paper, the color water-based ink penetrates instantly despite the paper feed roller hitting the recording paper surface, causing bleeding between different colors and feathering of dots. It showed excellent printing quality with high dot roundness and smooth solid surface. However, characters printed with black water-based ink had low resolution and blurred outlines, making them unsuitable for documents.

Comparative Example 2 Water-soluble dye 3.0% water
53.0% Glycerin 42.7% N-methyldiethanolamine 1.0% EDTA・4Na
O, 1% Omazine Na
As a 0.2% water-soluble dye, cyan color is C.1, Direct Blue 199, magenta color is C.
, 1, Direct Red 154, yellow color is C, [
, Direct Yellow 142 and black color are C91
, Direct Black 154 were used.

After mixing the above components and sufficiently dissolving them at room temperature, this solution was filtered using a 0.45 micron membrane filter to obtain color aqueous ink 4. The surface tension of each color water-based ink 4 was 60 dynes.

When each of the above color water-based inks was continuously ejected using a drop-on-demand jet printer designed to prevent the roller from hitting the printing surface, the result was 200.
Stable ink jetting was obtained even after hours. Furthermore, when printed on commercially available copy paper, the resolution of characters printed using black water-based ink alone was very high, and even complex characters with many strokes were printed beautifully, but in printed images where different colors touch each other, Color water-based inks including black had noticeable bleeding between different colors, and the printing quality was not necessarily good, with a rough feeling on the rough surface.

(Effects of the Invention) According to the color printing method using the inkjet recording method of the present invention, there is no occurrence of roller marks, feathering, bleed, or satellites.
Printed images with excellent resolution can be formed on permeable recording media such as plain paper.

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Claims (1)

[Claims] 1. (1) After printing on a permeable recording medium using a color water-based ink having a surface tension in the range of 30 to 40 dynes, (2) printing on the same recording medium with a surface tension in the range of 30 to 40 dynes; A color printing method using an inkjet recording method, characterized in that printing is performed using color aqueous ink in the range of 45 to 73 dynes. 2. A color water-based ink having a surface tension in the range of 30 to 40 dynes contains water, a water-soluble dye, an anti-drying agent, and a penetrant, and the penetrant is (a) a compound represented by the following general formula (I). , (b) a compound represented by the following general formula (II), and (c) a compound that is an ethylene oxide or propylene oxide adduct of butyl alcohol, and the number of moles added is in the range of 1 to 5. 2. A color printing method using an inkjet recording system according to claim 1, wherein the color printing method contains one or more compounds. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 is a hydrogen atom, a methyl group, a methoxy group,
It represents a chlorine atom or a bromine atom, and n represents an integer of 1 to 5. ) General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^2 is a hydrogen atom, a methyl group, a methoxy group,
It represents a chlorine atom or a bromine atom, and m represents an integer of 1 to 5. 3. The color printing method using an inkjet recording system according to claim 1, wherein the color water-based ink having a surface tension in the range of 45 to 73 dynes contains water, a water-soluble dye, and a drying inhibitor.