JPH09109548A - Ink set and method for ink jet recording using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a clear color image with high color density and a sharp edge, without line thickening even when two inks of different colors are printed one on another and without boundary extruding even when two inks of different colors are printed adjoiningly. SOLUTION: In an ink set used for a method for ink jet recording wherein a color image is recorded on a material to be recorded by using inks of at least two different colors by means of a method for ink jet recording system, the ink contains a dye, a liq. medium and a polymer substance as essential ingredients and has a viscosity of 1×10<-3> to 1×10<-2> Pa.s at 25 deg.C and a dye used for at least one ink among inks with at least two different colors is an anionic dye and a dye used for an ink with a different color from the ink is a combination of cationic dyes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink set for recording a color image on a recording material by using a plurality of colored inks and combining the primary colors of these inks, and an inkjet recording method using the same. The present invention relates to a recording method by an inkjet method which has a sufficient image density and can obtain a clear and high-quality image.

[0002]

2. Description of the Related Art Ink jet recording methods utilize an electrostatic attraction method by applying a high voltage, a method of mechanically vibrating or displacing colored ink (ink) using a piezoelectric element, and a pressure for heating and foaming the ink. Ink droplets are generated by various ink ejection methods, such as the ink jet method, and are ejected to adhere to a recording material such as paper to form ink dots for recording, which reduces noise. It is a recording method that enables high-speed printing and multicolor printing.

A printed matter recorded by using this ink jet recording system is, for example, for observing a surface image using a paper or a so-called ink jet recording paper as a recording material, or has a translucency as a recording material. A recording material that is used to project a recorded image on a screen or the like with an optical device such as a slide or an OHP (overhead projector) for observation, a color separation plate when a positive plate for color printing is prepared, It is applied to various applications such as being used as a CMF (color mosaic filter) used in a color display such as liquid crystal.

On the other hand, in the case of forming a color image by such an ink jet recording method, a recording method by a subtractive color mixture method is a representative method. When a color image is formed by the subtractive color mixture method, three primary colors of cyan (C), magenta (M) and yellow (Y) are generally used.

The following four colors are basically the colors that can be expressed by mixing these three primary colors in the same pixel, that is, by depositing and recording different color ink droplets on the same pixel. Is. (1) C + M → B (blue) (2) C + Y → G (green) (3) M + Y → R (red) (4) C + M + Y → Bk (black)

As described above, the colors represented by the three primary colors of C, M and Y are basically seven colors of C, M, Y, R, G, B and Bk, and are composed of these seven colors. Multicolor images are called false color images. Therefore, when recording by such a recording method, basically, C,
It is sufficient to prepare three inks for the three primary colors of M and Y.

However, when Bk is represented by the three primary color inks of C, M and Y, Bk is printed by overlapping the three primary color ink droplets of C, M and Y, and the ink droplet capacities are the same for each color. Since three ink droplets are deposited on the recording material in an overlapping manner, the dots formed thereby expand more than necessary compared to the portion recorded in a color other than Bk, and a line thickening occurs. It may look unnatural,
Since the amount of ink in that portion is large, there is a problem that the recording material causes defective ink absorption. Furthermore, when recording is performed, this problem is important because the frequency of recording by Bk is generally high. Therefore, in general, Bk
In the case of, the Bk ink is used in addition to the three primary color inks of C, M and Y.

[0008]

However, C,
When recording is performed using four color inks of M, Y and Bk,
As described above, in the printing portions of B, G, and R, when two ink droplets of different colors are overlaid, when the recording material is a high-quality paper containing a sizing agent, the increased ink droplets are added. It takes a certain amount of time to absorb the ink droplets, and while absorbing the ink droplets, the ink droplets enter the voids between the fibers of the paper not only in the cross-sectional direction of the recording material but in all directions, resulting in uneven dots. However, there is a problem that irregular line thickening, so-called feathering occurs, the edge of the recorded image lacks in sharpness, and the image becomes unclear.

Further, even when two ink droplets of different colors are ejected adjacent to each other, the ink is partially mixed at the boundary portion without being fixed, resulting in blurring of the boundary between the different colors, resulting in an unclear image. Becomes

As one method for solving the above problems, it is considered that the permeation rate of ink droplets into the recording material is increased. By doing so, the surface tension of each color ink is lowered and the wettability to the recording material can be improved.

However, in the ink whose surface tension is lowered, dots are enlarged more than necessary on the recording material to cause line thickening, and permeation is accelerated to cause sinking of the coloring material into the recording material. The density is remarkable, and a decrease in color density may occur.

For example, Bk is frequently used as a character as described above, the color density of the character is higher than other colors, and a sharp edge without unnatural line thickening is formed. It is more preferable to give the image a visual impression. Therefore, if only Bk is recorded with an ink having a somewhat high surface tension and the permeation speed into the recording material is reduced, a clear black image having a high color density is certainly obtained, but in this case, Bk and other colors There is a problem that the problem of feathering when inks are overlaid and the problem of boundary blurring between Bk and another color image adjacent to Bk cannot be solved.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to record a color image with three or more color inks containing Bk, which is particularly versatile and has a high size. An object of the present invention is to provide an ink set capable of forming a color image having high color density and sharp edges on a recording paper, and an inkjet recording method using the same.

Even when two different color inks are printed at the same time, there is no irregular line thickening and the different color inks
Boundary blur when two inks are printed adjacent to each other,
An object of the present invention is to provide an ink set capable of forming a clear color image and an inkjet recording method using the same.

[0015]

That is, the first invention of the present invention relates to an ink set used in an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink. The ink contains a dye liquid medium and a polymer substance, has a viscosity at 25 ° C. of 1 × 10 ⁻³ to 1 × 10 ⁻² pa · s, and 2
The dye used in at least one color ink among the inks of two or more colors is an anionic dye, and the dye used in the ink of a different color from the ink is a combination of cationic dyes, and at the same time, in at least one color ink, The ink set is characterized by having an ionic surfactant of the same polarity as the dye used therein.

In the ink set of the first invention, the dye constituting one color ink is an anionic dye, and the polymer substance is a water-soluble anionic or nonionic polymer, and at the same time, an anionic interface. It is preferable that the dye containing the activator and constituting the ink of a color different from that of the ink is a cationic dye, and the polymer substance is a cationic or nonionic polymer.

In the above-mentioned ink set of the first invention, the dye constituting one color ink is an anionic dye, and the polymer substance is a water-soluble anionic or nonionic polymer. It is preferable that the dye constituting the inks of different colors is a cationic dye, and the polymer substance is a cationic or nonionic polymer, and at the same time contains a cationic surfactant.

In the ink set of the first invention, the dye constituting one color ink is an anionic dye, and the polymer substance is a water-soluble anionic or nonionic polymer, and at the same time, an anionic interface. A dye that contains an activator and that constitutes an ink of a color different from that of the ink is a cationic dye, and the polymer substance is a cationic or nonionic polymer, and at the same time, contains a cationic surfactant. Is preferred.

The above-mentioned polymer substance has a weight average molecular weight of 30.
It is preferably in the range of 100 to 100,000. The molecular weight of the anionic surfactant and the cationic surfactant is preferably in the range of 100 to 3000.

A second invention of the present invention is an ink jet recording method characterized by using the ink set of the first invention. In the above-mentioned inkjet recording method of recording a color image on a recording material by an inkjet recording method using two or more colors of ink, it is preferable to heat and dry the printed matter immediately after printing. Further, it is preferable that the ink jet recording method is an ink jet recording method using heat energy.

A third invention of the present invention is an ink set used in an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink, wherein the ink is a dye, a water-soluble ink. Contains a liquid medium and a water-soluble polymer, and has a viscosity of 1 x 1 at 25 ° C.
0 ^-3 was ^{~1 ×} 10 -2 ^{pa ·} s, and dyes used in at least one color ink of the two or more colors of ink is a water-soluble dye, used in the ink of a different color than the ink The dye is a combination of water-insoluble dyes,
At the same time, the ink set using at least the water-insoluble dye has an ionic surfactant having a polarity opposite to that of the dye used in the ink using the water-soluble dye. The weight average molecular weight of the above polymer is 3
It is preferably in the range of 000 to 100,000.

A fourth invention of the present invention is an ink jet recording method characterized by using the ink set of the third invention. In the above-mentioned inkjet recording method of recording a color image on a recording material by an inkjet recording method using two or more colors of ink, it is preferable to heat and dry the printed matter immediately after printing. Further, it is preferable that the ink jet recording method is an ink jet recording method using heat energy.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Invention and Second Invention) A first invention of the present invention is an ink set used in an inkjet recording method for recording a color image on a recording material by an inkjet recording method using two or more colors of ink. The ink contains a dye liquid medium and a polymer substance, has a viscosity at 25 ° C. of 1 × 10 ⁻³ to 1 × 10 ⁻² pa · s, and is an ink of at least one color of two or more color inks. The dye used in the ink is an anionic dye, and the dye used in the ink of a different color from the ink is a combination of cationic dyes, and at the same time, the ink of at least one color has the same ionic property as that of the dye used in the ink. An ink set having a surfactant.

A second invention is an ink jet recording method using the above ink set.

In the present invention, in an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more different colors of ink, the ink contains a dye, a liquid medium and a polymeric substance as essential components. The dye contained in the ink of at least one color is an anionic dye, and the polymer contained in the ink is a water-soluble non-cationic polymer containing an anionic polymer and a nonionic polymer. The dye contained in the color ink is a cationic dye, and the polymer substance also contained is a water-soluble non-anionic polymer substance containing a cationic polymer and a nonionic polymer. In addition to the above dye and polymer substance, an anionic or cationic surfactant is used in combination.

According to the inkjet recording method of the first aspect of the present invention, a water-soluble non-cationic polymer substance containing an anionic dye and an anionic polymer or a nonionic polymer is used for at least one color of ink, Furthermore, by using a water-soluble non-anionic polymer substance containing a cationic dye and a cationic polymer or a nonionic polymer for inks of other colors, two or more inks of different colors can be overprinted almost simultaneously, or Since it is possible to suppress color mixing when ink of a different color from another ink is ejected adjacently before any one of the inks becomes dry on the recording material, feathering due to irregular line thickening or It is possible to reduce the boundary blur between adjacent different colors.

That is, when two different color inks are ejected adjacent to each other, in order to form an insoluble salt by reacting at the time when the anionic and cationic dyes which are the dyes constituting each ink come into contact with each other. However, when the diffusion speed between two liquids is higher than the reaction insolubilization speed, the effect of suppressing color mixing may be insufficient. .

Therefore, in order to make this effect more sufficient, it is necessary to further suppress the diffusion rate between the liquids described above. For this purpose, it is possible to increase the viscosity by causing each ink to contain a polymer substance, or to cause a film forming action on the surface of the recording material. At the same time, the penetrability below the surface of the recording material is suppressed, the expansion of the dot diameter and the non-uniform line thickening are suppressed, so that the edge of the recorded image becomes sharp and high color density can be obtained.

As a more preferable combination, in one color ink, the dye is an anionic dye and the high molecular weight substance is an anionic polymer, and in the other color inks,
When the dye is a cationic dye and the polymer substance is a cationic polymer, in addition to the above effects, insolubilization of the polymer substances due to salt formation occurs at the interface between the liquids, so that the effect of suppressing color mixing is further large.

As another preferable combination, in one color ink, the dye is an anionic dye and the polymer substance is a water-soluble anionic or nonionic polymer, and in the other color ink, the dye is a cationic dye. Dyes and polymeric substances are cationic or nonionic polymers,
Moreover, if it also contains a cationic surfactant,
In addition to the above effects, insolubilization due to salt formation between an anionic dye and a cationic surfactant or salt formation between an anionic polymer substance and a cationic surfactant occurs at the interface between liquids. Greatly suppresses color mixture.

Similarly, in the ink of one color, the anionic dye and the polymer substance are water-soluble anionic or nonionic polymers, and at the same time contain an anionic surfactant, and inks of other colors In the above, in the case where the dye is a cationic dye and the polymer substance is a cationic or nonionic polymer, in addition to the above effects, salt formation between the cationic dye and an anionic surfactant or a cationic polymer substance Since the insolubilization of the salt with the anionic surfactant due to salt formation occurs at the interface between the liquids, the effect of suppressing color mixing is further large.

In the ink jet recording method of the present invention, in order to more effectively suppress the diffusion between the liquids of two colors and suppress the color mixture at the boundary surface between the liquids, it is necessary to perform heating and drying forcibly. This is possible by improving the quick drying property of the recording liquid.

As described above, the water-soluble recording liquid used in the ink set of the first invention of the present invention is obtained by dissolving the above-mentioned water-soluble dye and water-soluble polymer substance in a suitable liquid medium. .

In the present invention, as the color component of the ink,
As the anion dye that is preferably used, existing ones, newly synthesized ones, as long as they have an appropriate color tone and density, most of them such as direct dyes, acid dyes and reactive dyes are used. You can do it. Further, any of these may be mixed and used.

Examples of anionic dyes include C.I. I. Direct yellow 8, 11, 12, 27,
28, 33, 39, 44, 50, 58, 85, 86, 8
7, 88, 89, 98, 100, 110 C.I. I. Direct Red 2, 4, 9, 11, 20,
23, 24, 31, 39, 46, 62, 75, 79, 8
0, 83, 89, 95, 197, 201, 218, 22
0, 224, 225, 226, 227, 228, 230 C.I. I. Direct Blue 1, 15, 22, 25, 4
1, 76, 77, 80, 86, 90, 98, 106, 1
08, 120, 158, 163, 168, 199, 22
6

C. I. Acid Yellow 1, 3, 7,
11, 17, 23, 25, 29, 36, 38, 40, 4
2, 44, 76, 98, 99 C.I. I. Acid Red-6,8,9,13,14,
18, 26, 27, 32, 35, 42, 51, 52, 8
0, 83, 87, 89, 92, 106, 114, 11
5, 133, 134, 145, 158, 198, 24
9, 265, 289 C.I. I. Acid Blue 1, 7, 9, 15, 22, 2
3, 25, 29, 40, 43, 59, 62, 74, 7
8, 80, 90, 100, 102, 104, 117, 1
27, 138, 158, 161

C. I. Reactive Yellow 2,
3, 17, 25, 37, 42 C.I. I. Reactive Red 7, 12, 13, 1
5, 17, 20, 23, 24, 31, 42, 45, 4
6,59 C.I. I. Reactive Blue 4, 5, 7, 13, 1
4, 15, 18, 19, 21, 26, 27, 29, 3
2, 38, 40, 44, 100 C.I. I. Food Yellow 3 C.I. I. Hood Red 87, 92, 94

C. I. Direct Black 17,1
9, 22, 31, 32, 51, 62, 71, 74, 11
2, 113, 154, 168, 195 C.I. I. Acid Black 2, 48, 51, 52, 1
10, 115, 156 C.I. I. Reactive Black 1, 8, 12, 13 C.I. I. Food black 1, 2

Specific examples of the cationic dye used in the present invention include the following dyes. C. I. Basic Black 2,8 Aizen Catillon Black SBH,
BXH, SH, ACH, MH, TH (manufactured by Hodogaya Chemical) Sumiacryl Black B, R, AP, B
P, CP, FFP (Sumitomo Chemical Co., Ltd.) Diacryl Supra Black GSL, R
SL, ESL (manufactured by Mitsubishi Kasei)

C. I. Basic Yellow 1, 11,
13, 19, 25, 33, 36 C.I. I. Basic Red 1, 2, 9, 12, 13,
38, 39, 92 C.I. I. Basic Blue 1, 3, 5, 9, 19, 2
4, 25, 26, 28, 45, 54, 65 The anionic dyes and cationic dyes suitable for the present invention are not limited to the examples listed above.

The concentration of the dye in the ink is appropriately determined as desired, but is usually 0.1 to 15% by weight, preferably 0.5 to 10% by weight, and most preferably 1 to 5%. Is desirable.

The water-soluble polymer substance suitably used as a component of the ink in the first invention of the present invention, whether existing or newly synthesized, can have suitable physical properties for ink and performance capable of achieving the object. If you get, you can use most things.

Examples of the anionic polymer include polyacrylic acid or alkali salts thereof, polymethacrylic acid or alkali salts thereof, styrene-acrylic acid copolymers or alkali salts thereof, styrene-acrylic acid-acrylic acid alkyl ester copolymers or Alkali salts thereof, styrene-maleic acid copolymers or alkali salts thereof, styrene-maleic acid-acrylic acid alkyl ester copolymers or alkali salts thereof, styrene-methacrylic acid copolymers or alkali salts thereof, styrene-methacrylic acid- Acrylic acid alkyl ester copolymer or alkali salt thereof, styrene-maleic acid half ester copolymer or alkali salt thereof, vinylnaphthalene-maleic acid copolymer or alkali salt thereof, alginic acid or alkali salt thereof, carboxy Polysaccharides or their alkali salts such as chill cellulose, and sulfate polyvinyl or alkali salts. The alkali salts include alkali metal salts such as sodium, lithium and potassium, as well as ammonium salts, alkylamine salts, alkanolamine salts and the like, and these can be used alone or in appropriate combination of several kinds.

Examples of the nonionic polymer are polyvinyl ether derivatives such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyvinyl methyl ether, polyvinyl ethyl ether and polyvinyl isobutyl ether, polysaccharides such as cellulose, methyl cellulose and ethyloxyethyl cellulose, and polyalginic acid alginate. Alcohol ester, water-soluble urea resin, dextrin derivative, casein, polyvinyl ether compound, polyethylene oxide, polypropylene oxide or polyalkylene oxide containing a copolymer of both, and the like,
These may be used alone or in combination of a plurality of types as appropriate.

Examples of the cationic polymer include polyalkyleneimines including polyethyleneimine and polyisopropyleneimine, polyalkylenepolyamines, polyamines including polyamide polyamine epichlorhydrin, water-soluble aniline resin and salts thereof, polythiourea and polythiourea. Examples thereof include salts thereof, water-soluble cationized amino resin, polyvinyl pyridine and salts thereof, polyacrylamide cation modified products, and the like, and these can be used alone or in combination of several kinds as appropriate.

The weight average molecular weight of the water-soluble polymer substance in the ink is 3000 to 100,000, preferably 3000 to 50000, and most preferably 3000 to 200.
00. Further, the content of the water-soluble polymer substance in the ink is appropriately determined as desired, but it is usually 0.
001 to 20% by weight, preferably 0.01 to 15% by weight,
Optimally, 0.01 to 10% by weight is desirable.

As the liquid medium used in the present invention, an organic solvent is appropriately selected and used as desired. Specifically, for example, methyl alcohol, ethyl alcohol, n
-Propyl alcohol, iso-propyl alcohol,
n-butyl alcohol, sec-butyl alcohol, t
ert-butyl alcohol, iso-butyl alcohol, amyl alcohol, n-hexanol, cyclohexanol, and other alkyl alcohols having 1 to 7 carbon atoms; acetone, diacetone alcohol, and other ketones or ketone alcohols; monoethanolamine, diethanolamine, etc. Alkanolamines of

Amides such as dimethylformamide and dimethylacetamide; ethers such as tetrahydrofuran and dioxane; 2 to 6 alkylene groups such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, thiodiglycol, butylene glycol and glycerin Polyhydric alcohols containing carbon atoms of ethylene glycol monomethyl (or ethyl- or propyl-) ether, diethylene glycol monomethyl (or ethyl- or propyl-) ether, diethylene glycol dimethyl (or ethyl) ether, polyethylene glycol monomethyl (or ethyl-) ) Lower alkyl mono- or di-ethers derived from alkylene glycols such as ethers (total carbon number is 3)
~ 8);

Nitrogen-containing 5-membered ring ketones such as 2-pyrrolidone and N-methyl-2-pyrrolidone; Intramolecular esters of oxycarboxylic acids such as α-valero-lactone, ε-caprolactone and butyllactone; morpholine and dimethyl Examples thereof include imidazolidine sulfolane.

These solvents may be used alone,
Two or more kinds may be used as a mixture. The content of the water-soluble organic solvent used in the present invention in the ink is generally 5 to
90% by weight, preferably 10 to 80% by weight, more preferably 10 to 50% by weight.

Water is also used as the liquid medium used in the present invention. The content of water in the ink used in the present invention is generally 10 to 90% by weight, preferably 10 to 70% by weight.
It is desirable that the content is in the range of 20% by weight, more preferably 20 to 70% by weight.

In the first invention of the present invention, existing surfactants or newly synthesized surfactants that are preferably used as a component of the ink have appropriate physical properties for the ink and performance capable of achieving the object. Once obtained, most can be used.

The anionic surfactant has a carboxylic acid group, a sulfonic acid group, a sulfuric acid ester salt, a phosphoric acid ester salt, etc. in its hydrophilic group, and a hydrophobic group having 11 to 15 carbon atoms. Benzene having an alkyl group, alkylnaphthalene having 1 to 5 carbon atoms, alkylphenol having 12 to 18 carbon atoms, higher alcohol, higher mercaptan, higher fatty acid having 11 to 18 carbon atoms, and total carbon number of 8
-21 higher fatty acid esters, C11-17 polyhydric alcohol fatty acid partial esters, C11-11
Of higher fatty acid amide, other fats and oils, wax, etc. as raw materials.

The cationic surfactant has a quaternary ammonium salt, a quaternary ammonium salt of benzyl halide, an amine salt, an alkanolamine salt, a pyridinium salt, etc. in its hydrophilic group, and a hydrophobic group in its hydrophobic group. 11 carbon atoms
To 18 higher fatty acids, higher amines having 12 to 34 carbon atoms, higher fatty acid amides having 11 to 17 carbon atoms, higher alkyl halides having 11 to 17 carbon atoms, and the like.

The content of the surfactant in the ink is appropriately determined as desired, but is usually 0.001-10.
% By weight, preferably 0.001 to 5% by weight, optimally 0.
It is desirable to set it to 05 to 3% by weight.

The viscosity of the ink used in the present invention is 25.
The viscosity at 0 ° C. is 1 × 10 ⁻³ to 1 × 10 ⁻² pa · s, preferably 1.2 × 10 ^{−3 to} 5 × 10 ⁻³ pa · s. When the viscosity is less than 1 × 10 ⁻³ pa · s, the diffusion speed of the adjacent ink cannot be sufficiently reduced, and the viscosity is 1 × 10 ^−2.
If it exceeds pa · s, ejection from the orifice hole becomes difficult and a sufficient amount of ink cannot be ejected, which is not preferable.

(Third Invention and Fourth Invention) The third invention of the present invention is used in an ink jet recording method for recording a color image on a recording material by an ink jet recording system using two or more colors of ink. In the ink set, the ink contains a dye, a water-soluble liquid medium and a water-soluble polymer substance, and has a viscosity at 25 ° C. of 1 × 10 ⁻³ to 1 × 10 ^−2.
The dye used in at least one of the two or more color inks is a water-soluble dye,
The dye used in the ink of a color different from that of the ink is a combination of water-insoluble dyes, and at least an ink using a water-insoluble dye has a polarity opposite to that of the dye used in the ink using a water-soluble dye. An ink set having an ionic surfactant.

A fourth aspect of the present invention is an ink jet recording method using the above ink set.

The present invention is an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more different colors of ink, the ink containing a dye, a liquid medium and a polymer substance as essential components. The dye contained in the ink of at least one color is a water-soluble dye, the polymer substance contained therein is a water-soluble polymer substance, and the dye contained in the ink of other colors is an oil dye or a dispersion. It is a water-insoluble dye containing a dye, and the polymer substance also contained therein is characterized in that it is water-soluble.

According to the ink jet recording method of the present invention, a water-soluble dye used in at least one color ink and a water-soluble polymer substance are used, and the dye used in an ink of a color different from that of the ink is water-insoluble. An ink that uses at least a water-insoluble dye as a dye has an ionic surfactant having a polarity opposite to that of the dye used in the ink that uses a water-soluble liquid medium, a water-soluble polymer substance, and a water-soluble dye. By doing so, two or more inks of different colors are overlaid almost at the same time, or an ink of a different color is ejected adjacently before one of the inks becomes dry on the recording material. In this case, it is possible to suppress color mixing, and thus it is possible to reduce feathering due to irregular line weight and blurring of boundaries between adjacent different colors.

That is, when two different color inks are ejected adjacent to each other, the dyes which are the pigments forming the respective inks do not melt each other when they come into contact with each other, but rather repel each other. Although it suppresses color mixture, the effect of color mixture suppression may be insufficient when the diffusion speed between the two color liquids is still high.

Therefore, in order to make this effect more sufficient, it is necessary to further suppress the diffusion rate between the liquids described above. For this purpose, it is possible to increase the viscosity by causing each ink to contain a polymer substance, or to generate a film forming action on the surface of the recording material. At the same time, the penetrability below the surface of the recording material is suppressed, the expansion of the dot diameter and the non-uniform line thickening are suppressed, so that the edge of the recorded image becomes sharp and high color density can be obtained.

Furthermore, when a water-soluble dye and a water-soluble polymer substance used in at least one color ink are used and the water-soluble dye is anionic, the dye used in the ink of a color different from that of the ink For an ink that uses a water-insoluble dye and at least a water-insoluble dye at the same time, by using an aqueous liquid medium, a water-soluble polymer substance and a cationic surfactant, an anionic dye and a cationic surfactant can be obtained. Since insolubilization due to salt formation occurs at the interface between liquids, the effect of suppressing color mixing is great. On the contrary, when the water-soluble dye used in one color ink is cationic, the ink using a non-water-soluble dye of a different color from the ink uses an anionic surfactant, The same effect can be expected.

In the ink jet recording method of the present invention, the water-insoluble dyes containing oil-soluble dyes and disperse dyes, which are preferably used as color components of the recording liquid, are commercially available ones or newly synthesized ones. However, as long as it has appropriate color tone and density, most of them can be used, or any one of them can be mixed and used.

For example, C.I. I. Solvent Blue 33, 38, 42, 45,
53, 65, 67, 70, 104, 114, 115, 1
35 C. I. Solvent Red 25, 31, 86, 92,
97, 118, 132, 160, 186, 187, 21
9 C. I. Solvent Yellow 1, 49, 62, 74,
79, 82, 83, 89, 90, 120, 121, 15
1, 153, 154 and the like.

C. I. Solvent Black 3, 5,
7, 22, 23, 123 and the like.

C. I. Disperse Yellow 3, 4,
5, 7, 23, 33, 42, 49, 54, 56, 64,
71, 79, 82, 83, 86, 88, 93, 99, 1
16, 119, 141, 160, 163, 198, 20
4, 218, 224, 226, 230 C.I. I. Disperse Red 1, 4, 5, 7, 11,
12, 13, 15, 18, 30, 33, 43, 50, 5
2, 53, 54, 55, 56, 58, 59, 60, 6
5, 72, 73, 74, 75, 76, 82, 86, 8
8, 90, 91, 92, 96, 105, 106, 10
7, 110, 117, 118, 126, 127, 12
8, 131, 132, 134, 135, 136, 13
7, 140, 143, 145, 146, 151s, 15
3, 159, 164, 167, 169, 177, 18
1, 184, 188, 190, 191, 200, 20
3, 205, 206, 221, 223, 224, 22
5,227,229,239,240,258,27
7, 278, 279, 283, 288, 302, 30
9, 311, 312, 323, 329, 332, 34
0, 341, 343

C. I. Disperse Blue 1, 3,
7, 13, 19, 26, 27, 35, 44, 54, 5
5, 56, 60, 64, 65, 72, 73, 79, 8
1, 82, 87, 91, 93, 94, 96, 102, 1
06, 118, 120, 122, 125, 128, 13
0, 139, 142, 143, 146, 148, 14
9, 153, 154, 165, 167, 181, 83,
185, 186, 189, 198, 200, 201, 2
05, 207, 214, 224, 225, 257, 25
9, 266, 268, 270, 284, 285, 28
7, 288, 291, 293, 301, 330, 33
2,333,337,341,345,351,35
2, 353

C. I. Disperse Black 1, 9,
10, Black GL, Black B, Black
L, Black 2B, Black BT, Bla
ckOBL, Black RSR, Black TK,
Black TG, Black S-CTL, Blac
k H-DB, Black RD-SGT, Black
S-2BL, Black S-3BL, Black
S-5BL, Black S-BNL, Black S
-3GLN, Black S-ST, Black S-
FGB, Black S-SGN, Black S-W
LA, Black S-WLAT, Black B8
2, Black BTNU82, Black 2BL,
Black HR-FS, Black RB-FS, B
black HG-FS, Black BG-FS, Bla
ck KN-FS and the like.

The water-insoluble dyes including oil dyes or disperse dyes suitable for the present invention are not limited to the examples listed above.

The water-soluble dyes are the same anionic dyes and cationic dyes as those described in the first invention of the present invention, and existing ones and newly synthesized ones are suitable. If it has a good color tone and density,
Most things can be used. Further, any one of these may be mixed and used.

The concentration of the dye in the ink is appropriately determined as desired, but is usually 0.1 to 15% by weight, preferably 0.5 to 10% by weight, and most preferably 1 to 8% by weight. It is desirable to do.

The water-soluble polymer substance and the surfactant which are preferably used as the components of the ink in the method of the present invention are the same as those described in the section of the first invention of the present invention. Most of the newly synthesized compounds can be used as long as the ink has suitable physical properties and performance capable of achieving the purpose.

The content of the water-soluble organic solvent used in the present invention in the ink is generally 5 to 90% by weight, preferably 10 to 80% by weight, more preferably 10 to 50% by weight.

Water is also used as the liquid medium used in the present invention. The content of water in the ink is generally 10-9.
It is desirable that the amount is 0% by weight, preferably 10 to 70% by weight, more preferably 20 to 70% by weight.

The viscosity of the ink used in the present invention is 25.
Viscosity at 0 ° C. is 1 × 10 ⁻³ to 1 × 10 ⁻² pa · s, preferably 1.2 × 10 ^{−3 to} 5 × 10 ⁻³ pa ·
s. When the viscosity is less than 1 × 10 ⁻³ pa · s, the diffusion speed of the adjacent ink cannot be sufficiently reduced, and the viscosity is 1 × 1.
When it exceeds 0 ^-2 pa · s, it is difficult to eject the ink from the orifice hole and a sufficient amount of ink cannot be ejected, which is not preferable.

As the liquid medium used in the present invention, water or an organic solvent is appropriately selected and used as desired. Specifically, an aqueous solvent used in the water-soluble recording liquid used in the recording methods of the first and second inventions can be mentioned as an example.

In addition, in the recording liquid used in the present invention, a sorbitan fatty acid derivative, a sulfuric acid ester derivative, a polyoxyethylene alkylene ether type sulfuric acid ester, a phosphoric acid ester derivative, a dispersant or a solubilizing agent for a non-aqueous dye, Quaternary ammonium salt derivatives, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, fatty acids, alkenyl succinates, higher alcohol sulfuric acid ester salts, sodium alkylbenzene sulfonate, alkyl diphenyl ether disulfonates, naphthalene sulfonic acid folimarin condensation Surfactants including substances can be used as appropriate.

The recording liquids used in the recording methods of the first to fourth inventions of the present invention thus prepared have excellent affinity with recording materials having a high degree of size, high-speed recording property, or Has excellent optical density, color tone, water resistance, abrasion resistance or light resistance of a recorded image. Further, it is a practical recording liquid excellent in storage stability, signal responsiveness, droplet formation stability, ejection stability, continuous recording property and the like.

In the ink used in the recording method of the present invention, in addition to the various components as described above, various additives may be used for the purpose of further improving the physical properties of the ink. For example, a pH adjusting agent, a drying inhibitor of a crystalline organic compound such as urea, a viscosity adjusting agent, a surface tension adjusting agent such as various surfactants, an antifungal agent or a bactericidal agent, or ink droplets When a method of recording by electrifying and deflecting is adopted, a resistivity adjusting agent can be particularly mentioned.

In the recording method of the present invention, the liquid medium components or various additives are appropriately added as described above to prepare an ink having desired physical properties, and the ink is applied to various ink jet recording systems. Thus, a high-density and high-quality image is formed.

The recording method of the present invention uses three or more colors of ink including black to form an image by an inkjet method. The inkjet method applied to the recording method of the present invention is conventionally known. Any of the above methods can be used. That is, various inkjet recording apparatuses other than the recording apparatus having the recording head of the type that generates droplets by utilizing the mechanical vibration of the piezoelectric vibrator are also preferably used. For example, it can be applied to an apparatus or the like that applies a recording signal to the ink in the recording head in the form of thermal energy to generate droplets for recording.

The ink used in the recording method of the present invention may be used as ink for writing instruments such as felt-tip pens and fountain pens. However, when used as an ink for a writing instrument, it is necessary to prepare various properties such as viscosity and surface tension.

A recording apparatus applied to the ink jet recording method of the present invention, in which thermal energy corresponding to a recording signal is applied to the ink in the chamber of the recording head, and droplets are generated by the thermal energy for recording, will be described below. explain.

An example of the head structure, which is the main part of the apparatus, is shown in FIGS. 1, 2 and 3. The head 13 is a glass, ceramic, or plastic plate having a groove 14 through which ink passes, and a heating head 15 used for heat-sensitive recording (a head is shown in the drawing, but is not limited to this).
It can be obtained by closely attaching and. The heating head 15 includes a protective film 16 made of silicon oxide and an aluminum electrode 17-1.
17-2, heating resistor layer 1 formed of nichrome or the like
8, a heat storage layer 19, and a substrate 20 having a good heat dissipation property such as alumina. Ink 21 is a discharge orifice (micro hole)
Up to 22, a meniscus 23 is formed by a pressure (not shown).

Now, when an electric signal is applied to the electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith,
The meniscus 23 is projected by the pressure, the ink 21 is ejected, becomes a recording droplet 24 from the orifice 22, and is ejected toward the recording material 25.

FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely contacting a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described in FIG. FIG.
2 is a cross-sectional view of the head 13 taken along the ink flow path, and FIG. 2 is a cross section taken along the line AB of FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end, and forms a cantilever. The blade 61 is arranged at a position adjacent to the recording area of the recording head.

Further, in the case of this example, the recording head is held in a protruding form in the moving path. 62 is a cap,
It is arranged at the home position adjacent to the blade 61,
The recording head is configured to move in a direction perpendicular to the direction of movement of the recording head, contact the ejection port surface, and perform capping. 6 more
Reference numeral 3 denotes an ink absorber disposed adjacent to the blade 61, and is held in a form protruding into the movement path of the recording head, similarly to the blade 61. The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the ink ejection port surface.

Reference numeral 65 denotes a recording head which has an ejection energy generating means and ejects ink to a recording material facing the ejection port surface where the ejection port is arranged for recording, and 66 is equipped with this recording head 65. And a carriage for moving the recording head 65. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown).
As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the adjacent area.

Reference numeral 51 is a paper feed section for inserting a recording material, and 52 is a paper feed roller driven by a motor (not shown). With such a configuration, the recording material is fed to a position facing the ejection port surface of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as recording proceeds.

In the above configuration, when the recording head 65 returns to the home position after recording is completed, the head recovery unit 6
The cap 62 of 4 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port surface of the recording head 65 is wiped. When capping is performed with the cap 62 in contact with the ejection surface of the recording head 65, the cap 62 moves so as to protrude into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same positions as the above wiping positions. As a result, even in this movement, the ejection port surface of the recording head 65 is wiped.

The above-mentioned movement of the recording head to the home position is performed not only at the end of recording or at the time of ejection recovery, but also at the home adjacent to the recording area at a predetermined interval while the recording head moves in the recording area for recording. The wiper is moved to the position, and the wiping is performed along with the move.

[0095]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 8 and Comparative Examples 1 to 8 In the following Examples and Comparative Examples, Examples 1 to 4 and Comparative Examples 1 to 4 relate to the first and second inventions of the present invention. Examples 5-8 and Comparative Examples 5-8 are the third of the present invention,
The present invention relates to the fourth invention.

In the following Examples and Comparative Examples, recording liquids containing water-soluble dyes (Examples 1 to 8 and Comparative Examples 1 to 1) were used.
The adjustment method of 8) is as follows. That is, each component of the recording liquid was sufficiently stirred in a container, and pressure-filtered with a Teflon filter having a pore size of 1 μm to adjust.

Further, in the following Examples and Comparative Examples,
The method for preparing the recording liquid (Examples 5 to 8 and Comparative Examples 5 to 8) using the water-insoluble dye is as follows. That is, each component of the recording liquid is sufficiently stirred in a container, and 50% of the volume of zirconium beads is converted into a volume, and then about 3% is dispersed by a disperser.
After crushing for a long time, coarse particles are removed by pressure filtration with a Teflon filter having a pore size of 2.5 μm, and the pH is adjusted to 7 to 9 with a pH adjusting agent such as sodium hydroxide, followed by stirring, and then Teflon having a pore size of 1 μm. It was adjusted by pressure filtration with a filter.

[0099]

[Table 1]

[0100]

[Table 2]

[0101]

[Table 3]

[0102]

[Table 4]

[0103]

[Table 5]

[0104]

[Table 6]

[0105]

[Table 7]

[0106]

[Table 8]

[0107]

[Table 9]

[0108]

[Table 10]

[0109]

[Table 11]

[0110]

[Table 12]

[0111]

[Table 13]

[0112]

[Table 14]

[0113]

[Table 15]

[0114]

[Table 16]

A recording apparatus having an on-demand type recording head (ejection orifice diameter 50 μm, piezo-vibrator driving voltage 60 V, frequency 4 KHz) for ejecting ink by a piezo-vibrator using the inks of the above-mentioned respective examples and comparative examples. Thus, the examination of T _{1 to} T ₄ described below was conducted.

T ₁ Monochromatic printing quality for various recording materials: Each recording ink was printed alone on the recording materials shown in Table 17, and the printing quality of a monochromatic image was evaluated according to the following criteria. The results are shown in Tables 18 and 19.

A: The edge portion of the dot was sharp, and feathering did not occur. B: Some bleeding was seen at the edge part of the dot, and the feathering was a little worrisome. C: The edge portion of the dot was considerably blurred, and feathering was remarkable.

T ₂ Two-color mixed color printing quality for various recording materials; Bk, C, M and Y on the recording materials shown in Table 17
The printing quality of a two-color mixed image when two inks of any two inks were overprinted on the same point was evaluated according to the following criteria. The results are shown in Tables 18 and 19.

A: Dots did not spread in an irregular shape. B: The dot shape was slightly irregular and lacked in circularity. C: The shape of the dots was extremely irregular and the line thickening was remarkable.

T ₃ Color Density of Each Color on Various Recording Materials: The inks of each color of Examples 1 to 8 were solid-printed on the recording materials described in Table 17. The color density at this time was 1.2 or more in terms of image density (OD). T ₄ Boundary bleeding between solid printing portions of different colors on various recording materials; immediately after solid printing with any ink on the recording material shown in Table 17, solid printing with different color ink adjacent to it Then, the following criteria were evaluated. The results are shown in Tables 18 and 19.

A: Almost no boundary blurring. B: Bleeding around the border is a little worrisome. C: Bleeding is remarkable. D: Very different from the desired image.

[0122]

[Table 17]

Evaluation Table 18 below shows the viscosities of the inks used in Examples 1 to 8 of the method of the present invention and Table 19 below, and the characteristics of the images obtained above. T ₁ , T ₂ ,
The evaluation results of T ₄ are shown.

[0124]

[Table 18]

Table 18 shows the viscosities of the inks used in Examples 1 to 8 of the present invention and the characteristics of the obtained images.
The evaluation results of ₁ , T ₂ and T ₄ are shown.

Further, an on-demand type multi-head (printing orifice diameter: 35 μm, heating resistor resistance value: 150 Ω, driving voltage: 30 V, frequency: 2 KH) is used, in which thermal energy is applied to ink in the recording head to generate droplets for recording.
A similar examination was conducted using a recording device having z).
The same excellent results as those of the recording device using the piezoelectric vibrator described above were obtained.

[0127]

[Table 19]

In Table 19, the same examinations as in the examples were carried out with respect to the viscosities of the inks used in Comparative Examples 1 to 8 and the characteristics of the obtained images. As a result, all of T ₁ , T ₂ , and T ₄
Each of the above items was not satisfied at the same time.

[0129]

As described above, according to the present invention, a high-quality color image having a high density and a sharp edge can be obtained on a recording paper having high versatility and high size. Furthermore, when two different-color inks are overlaid and printed, the resulting image does not have irregular line thickening, and there is no boundary bleeding when images of two different-color inks are continuously printed adjacent to each other. A clear color image can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a head section of an ink jet recording apparatus.

FIG. 2 is a cross-sectional view of a head section of the inkjet recording apparatus.

FIG. 3 is an external perspective view of a head obtained by multiplying the head shown in FIG. 1;

FIG. 4 is a perspective view illustrating an example of an ink jet recording apparatus.

[Explanation of symbols]

 13 Head 14 Groove 15 Heating Head 16 Protective Film 17-1, 17-2 Aluminum Electrode 18 Heating Resistor Layer 19 Heat Storage Layer 20 Substrate 21 Ink 22 Ejection Orifice 23 Meniscus 24 Recording Droplet 25 Recorded Material 26 Multi-groove 27 Glass Plate 28 Heat generating head 40 Ink accommodating section 42 Plug 44 Ink absorber 45 Ink cartridge 51 Paper feeding section 52 Paper feeding roller 53 Paper discharging roller 61 Blade 62 Cap 63 Ink absorbing body 64 Discharge recovery section 65 Recording head 66 Carriage

Claims (13)

[Claims] 1. An ink set used in an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink, the ink containing a dye liquid medium and a polymer substance, Viscosity at 25 ° C. is 1 × 10 ⁻³ to 1 × 10 ⁻² pa · s, and the dye used in at least one of the two or more color inks is an anionic dye, which is different from the ink. An ink set characterized in that the dye used in the color ink is a combination of cationic dyes, and at the same time, the ink of at least one color has an ionic surfactant of the same polarity as the dye used therein. 2. In the ink set, the dye constituting one color of ink is an anionic dye, the polymer substance is a water-soluble anionic or nonionic polymer, and the ink of a color different from that of the ink is used. The ink set according to claim 1, wherein the dye constituting the ink is a cationic dye, and the high molecular substance is a cationic or nonionic polymer. 3. The weight average molecular weight of the polymer substance is 30.
The ink set according to claim 1 or 2, which has a range of 00 to 100,000. 4. The molecular weight of the ionic surfactant is 1
The ink set according to claim 1, which is in a range of 00 to 3000. 5. An inkjet recording method using the ink set according to claim 1. 6. An ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink, wherein the printed matter is heated and dried immediately after printing. Inkjet recording method. 7. The inkjet recording method according to claim 5, wherein the inkjet recording method is an inkjet recording method using heat energy. 8. An ink set used in an ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink, wherein the ink is a dye, a water-soluble liquid medium and a water-soluble polymer. Containing a substance, the viscosity at 25 ° C. is 1 × 10 ⁻³ to 1 × 10 ⁻² pa
・ S and at least one of two or more color inks
The dye used in the color ink is a water-soluble dye, and the dye used in the ink of a different color from the ink is a combination of water-insoluble dyes. An ink set comprising an ionic surfactant having a polarity opposite to that of the dye used in the ink using the dye. 9. The weight average molecular weight of the polymer substance is 30.
The ink set according to claim 8, which is in a range of 00 to 100,000. 10. The molecular weight of the ionic surfactant is 10.
The ink set according to claim 8, which is in a range of 0 to 3000. 11. An inkjet recording method using the ink set according to claim 8. 12. An ink jet recording method for recording a color image on a recording material by an ink jet recording method using two or more colors of ink, wherein the printed matter is heated and dried immediately after printing. Inkjet recording method. 13. The ink jet recording method is an ink jet recording method using heat energy.
Or the inkjet recording method according to item 12.