JPH09151349A - Ink set, method for recording using the same and instrument using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set using an ink capable of obtaining a sufficient picture concentration, having a high homogeneity, especially preventing bleedings in color pictures, obtaining clear and uniform pictures and improving letter qualities in a printed matter. SOLUTION: In this ink set which consists of plural kinds of inks containing color materials and liquid media for dissolving or dispersing the color materials, at least one kind of ink in the plural kinds of inks contains an amphoteric high molecular weight compound which is a copolymer of a monomer having an anionic group in a molecule with a monomer having a cationic group in a molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink set used for recording a color image on a recording material by using a plurality of primary color inks and combining these primary color inks.
The present invention relates to an inkjet recording method and an inkjet device, and in particular, an ink set having excellent color development on plain paper in image recording by an inkjet method, a clear and high-quality image can be obtained, and a printed matter having excellent water resistance,
The present invention relates to an inkjet recording method and an inkjet device using the same.

[0002]

2. Description of the Related Art Ink jet recording methods include an electrostatic attraction method by applying a high voltage, a method of mechanically vibrating or displacing ink (colored ink) using a piezoelectric element, and a pressure at which the ink foams when heated. A method of generating small droplets of ink by various ink ejection methods such as a method utilizing ink, flying these to adhere the ink to a recording material such as paper, and forming ink dots for recording. It is a recording system that generates less noise and can perform high-speed printing and multi-color printing.

In particular, Japanese Patent Publication No. 61-59 by the applicant of the present application.
No. 911, Japanese Patent Publication No. 61-59912, Japanese Patent Publication No. 61-59914, etc., that is, an electrothermal converter is used as a means for supplying ejection energy, and thermal energy is applied to ink to generate bubbles. According to the method of generating droplets by generating the droplets, it is possible to easily realize a high density multi-orifice of the recording head, and it is possible to record a high resolution and high quality image at high speed.

However, the ink used in conventional ink jet recording generally contains water as a main component,
For this purpose, a water-soluble high-boiling point solvent such as glycol is generally contained for the purpose of preventing drying and clogging. When recording is performed on plain paper using such an ink, the ink penetrates into the inside of the recording material so that a sufficient image density cannot be obtained, or the filler or sizing agent on the surface of the recording material is not obtained. The image density may be uneven due to the uneven distribution of the image. In particular, when a color image is to be obtained, since the inks of a plurality of colors are successively overlapped with each other before the previously recorded ink is fixed, the color blurs or the ink Were mixed non-uniformly (hereinafter referred to as bleeding), and a satisfactory image could not be obtained. Further, in recent years, the demand for water resistance of printed matter has been increasing, and from this point as well, a satisfactory water resistant printed matter has not been obtained.

As a means for solving the above-mentioned problems, Japanese Patent Laid-Open No.
Japanese Patent Laid-Open No. 5-65269 uses an ink in which a compound that enhances permeability such as a surfactant is added to the ink.
Further, Japanese Patent Laid-Open No. 55-66976 discloses the use of an ink mainly composed of a volatile solvent. Further, US Pat. No. 5,106,416 discloses an ink containing a cationic dye, an amphoteric surfactant and a nonionic amphiphile. Also, US Pat. No. 53424
No. 40 discloses an ink containing a water-insoluble dye, a polymer colloid and a surfactant. Further, JP-A-60-96673 and JP-A-4-13927.
No. 2 discloses an ink using a betaine type acrylic resin.

However, when the ink disclosed in Japanese Patent Laid-Open No. 55-65269 is added with a compound that enhances the permeability such as a surfactant, the permeability of the ink to the recording material is increased. Although the bleeding is improved and the bleeding is suppressed to some extent, the ink penetrates deeply into the recording material including the colorant, which causes a problem such as a decrease in image density. Further, since the wettability with respect to the surface of the recording material is improved, the ink is likely to spread on the surface of the recording material, resulting in a decrease in resolution and bleeding, which is not preferable. Further, when the ink mainly composed of a volatile solvent disclosed in JP-A-55-66976 is used, in addition to the above-mentioned inconvenience, clogging due to evaporation of the solvent in the nozzle portion of the recording head is caused. It was easy to occur and was not preferable.

Further, in the ink containing the cationic dye, the amphoteric surfactant and the nonionic amphiphilic substance described in US Pat. No. 5,106,416, the colorant is added by adding the surfactant at a critical micelle concentration or more. The above-mentioned JP-A-55-65269 is basically used to prevent the diffusion of
As in Japanese Patent Laid-Open Publication No. 2003-163, due to the action of the surfactant, the penetrability of the ink itself was increased and a favorable image could not be obtained. or,
In the case of the ink containing the water-insoluble dye, polymer colloid and surfactant of US Pat. No. 5,342,440, in addition to the disadvantages of US Pat. No. 5,106,416, water insolubility in the recording head and in the nozzle The nozzle may be clogged due to the deposition of the dye and the aggregation of the colloid, which is not preferable.

Further, JP-A-60-96673 and JP-A-4-139272 disclose inks using a betaine type acrylic resin. The former is for the purpose of preventing bleeding of the oil-based ink, and The latter is disclosed to add the above acrylic resin for the purpose of improving the stability of the pigment ink, but high image quality on plain paper cannot be obtained. or,
Here, the betaine-type acrylic resin surely exhibits amphoteric characteristics, but it is difficult to say that it clearly has a cationic group and an anionic group, and further, a monomer having an anionic group in the molecule and a cationic group. It is not a copolymer of monomers having groups and has no isoelectric point. Therefore, it is basically different from the amphoteric polymer compound used in the present invention described later.

[0009]

The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a sufficient image density in recording a recording material, particularly plain paper, and to obtain an image density. Ink set consisting of a plurality of inks with high uniformity, preventing bleeding especially in color images, obtaining clear and uniform high-quality images, and further improving the character quality of printed matter; inkjet using the same A recording method and an inkjet device are provided.

[0010]

The above object is achieved by the present invention described below. That is, the present invention is an ink set comprising a plurality of types of ink containing a coloring material and a liquid medium that dissolves or disperses the coloring material, and at least one type of the plurality of types of ink contains at least one anionic group in its molecule. An ink set comprising an amphoteric polymer compound, which is a copolymer of a monomer having a cation and a monomer having a cationic group in the molecule, an inkjet recording method and an inkjet device using the same.

The present inventors have found that an ink containing a coloring material and a liquid medium in which the coloring material is dissolved or dispersed contains an amphoteric polymer compound having an anionic group and a cationic group, and
By recording using an ink set consisting of an ink containing an anionic or cationic surfactant,
It has been found that a recorded image meeting the above purpose can be obtained.
That is, when an amphoteric polymer compound having an anionic group and a cationic group is added to the ink, the amphoteric polymer compound in the ink causes the anionic polymer electrolyte and the cationic polymer to change due to the pH change of the ink. It exhibits the property of changing to an electrolyte. Here, when an anionic dye is used as the coloring material, by setting the pH of the ink to a value higher than the isoelectric point of the amphoteric polymer compound, the amphoteric polymer compound itself is anionic in the ink. The dye and the amphoteric polymer compound repel each other by acting as a polyelectrolyte exhibiting the above, and both exist stably.

On the other hand, in the other ink, a cationic dye is used as a coloring material, and the ink further contains a cationic polymer compound. When these inks are overprinted on the recording material or adjacent to each other, the anionic dye and the cationic polymer compound are
The anionic group of the cationic dye and the amphoteric polymer compound forms a salt, causing a rapid increase in viscosity and gelation. Furthermore, when the ink droplets fly from the recording head and come into contact with the surface of plain paper, the pH of the ink changes to a neutral region. Although the isoelectric point of the amphoteric polymer compound depends on its structure, it is generally in the neutral region, and therefore the amphoteric polymer compound exhibits both anionic and cationic properties and is in an electrically balanced state. Become. In this state, an anionic group and a cationic group of the amphoteric polymer compound form an internal salt with each other, causing a rapid increase in viscosity and gelation, and the cationic group of the amphoteric polymer compound, the dye and the anion. The salt forms with the anionic group of the surface active agent, and the coloring material is fixed in the polymer compound.

By immobilizing the coloring material in the polymer compound and thickening and gelling the amphoteric polymer compound, the coloring material in the ink is fixed near the surface of the recording material together with the polymer compound material. By converting it to a sufficient image density,
It is considered that the density uniformity is high, bleeding in a color image is prevented, and a high quality image can be obtained. or,
The coloring material is fixed in the polymer compound that made the internal salt, and the water solubility of the amphoteric polymer compound itself is also lowered by the formation of the internal salt, so that the water resistance of the printed matter is also improved. Seem.

Further, since the coloring material is fixed in the salted polymer compound and the water solubility of the polymer compound itself is lowered by salting, the water resistance of the printed matter is improved. I think that the. The above explanation is for the case of the combination of the amphoteric polymer compound and the anionic dye, but in the case of the combination with the cationic dye, the pH of the ink should be set to a value lower than the isoelectric point of the amphoteric polymer compound. Thereby, the same effect as the above can be obtained. Also, when using a pigment,
The pH of the ink is adjusted according to the surface charge of the pigment particles, and the same effect as described above is exhibited.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to embodiments. The ink set of the present invention comprises a plurality of types of ink containing a color material and a liquid medium that dissolves or disperses the color material. First, at least one kind of ink contains an amphoteric polymer compound. As the amphoteric polymer compound,
A copolymer obtained by copolymerizing a monomer having an anionic group such as a carboxyl group and a sulfone group in the molecule with a monomer having a cationic group such as an amino group, an imino group, a pyrrolidone ring and an imidazole ring is obtained. preferable. The form of copolymerization may be random, alternating, block or graft polymerization.

Suitable monomers having an anionic group include, for example, at least one carboxyl group and sulfonic group such as acrylic acid, itaconic acid, methacrylic acid, maleic acid, fumaric acid, styrene sulfonic acid, etc. The monomer which has an unsaturated bond is mentioned. In addition, as a monomer having a suitable cationic group, for example, at least one cationic group such as 2-vinylpyrrolidone, 4-vinylpyrrolidone, N-methylaminoethylmethacrylate, allylamine and diallylamine is contained, and a polymerizable non-polymerizable group is used. The monomer which has a saturated bond is mentioned.

Specific examples of the amphoteric polymer compound include allylamine-maleic acid copolymer and N-
Methylallylamine-maleic acid copolymer, 4-vinylpyridine-acrylic acid copolymer, N-methylaminoethylmethacrylate-methacrylic acid copolymer, acrylamide-styrenesulfonic acid copolymer and the like are preferably used. In addition, amphoteric proteins can be used among the proteins.

Other physical properties of the amphoteric polymer compound are not particularly limited, but preferably have a weight average molecular weight of 1,0.
00 to 1,000,000, more preferably 1,000
A range of 100,000 to 100,000 is desirable. If it is less than 1,000, the thickening and gelling effect due to pH change is small,
When it exceeds, 000,000, the initial viscosity of the ink increases and the ejection properties deteriorate, which is somewhat undesirable. Further, the isoelectric point of the amphoteric polymer compound can be appropriately adjusted by changing the copolymerization ratio of the monomer having an anionic group and the monomer having a cationic group. The isoelectric point of the amphoteric polymer compound has a pH in the range of 3 to 10, preferably 5 to 10. If the isoelectric point of the amphoteric polymer compound is less than pH 3 or more than pH 10, the desired effect of the ink is small and it is not preferable.

The amount of the amphoteric polymer compound added to the ink is 0.1 to 30% by weight, preferably 0.2 to
It is 10% by weight, more preferably 0.3 to 8% by weight. If it is less than 0.1% by weight, the desired effects of thickening and gelation due to pH change are small, and if it exceeds 30% by weight, the initial viscosity of the ink increases, which is not preferable. Examples of the anionic or cationic polymer compound used in the present invention will be given. Examples of the anionic polymer compound include an alkali-soluble resin, specifically, for example, sodium polyacrylate, or one obtained by copolymerizing a part of the polymer compound with acrylic acid. Yes, but of course it is not limited to these.

Examples of the cationic polymer compound include polyallylamine hydrochloride, polyamine sulfone hydrochloride, polyvinylamine hydrochloride, chitosan acetate, etc., but are not limited thereto. is not. Further, it is not limited to the above-mentioned hydrochloride type and acetate type. Further, as another specific example of the cationic polymer compound, for example, a compound obtained by cationizing a part of a nonionic polymer substance may be used. Specifically, for example,
Examples thereof include a copolymer of vinylpyrrolidone and a quaternary salt of aminoalkyl alkylate and a copolymer of a quaternary salt of acrylic amide and aminomethyl acrylic amide. Needless to say, however, the present invention is not limited to these compounds. . Further, the above-mentioned polymer compound is satisfactory if it is water-soluble, but it may be a dispersion such as latex or emulsion.

The position of the peak of the molecular weight distribution of these polymer compounds is preferably 1,500 or more and 10,000 or less in the practice of the present invention, but more preferably 1,500 or more 7, A compound of 000 or less is more preferable in that it does not reduce the color developability of the dye. or,
When a colorless or light-colored ink is applied to a recording material using an inkjet recording head, even if the content of the high molecular compound having a peak of the molecular weight distribution on the low molecular weight side is increased,
Since the solution viscosity is kept low, there is also an advantage that the ejection characteristics of the liquid are kept good.

Further, as the coloring material used in the ink, usual dyes and pigments are used. As the dye, for example, an acid dye, a basic dye, a direct dye, and the like, almost all of which can be used. The content of the coloring material is not particularly limited, but is preferably in the range of 0.1 to 20% by weight based on the total weight of the ink. As the anionic dye used as a component of the ink constituting the ink set of the present invention, most of the existing ones or newly synthesized ones can be used as long as they have appropriate color tone and density. Can be used. Further, any of these may be mixed and used. Specific examples of the anionic dye include the followings.

C. 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, 23
0, 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. I. Direct Black 17, 19, 22, 3
1, 32, 51, 62, 71, 74, 112, 113,
154, 168, 195, C.I. I. Acid Yellow 1, 3, 7, 11, 17,
23, 25, 29, 36, 38, 40, 42, 44, 7
6, 98, 99,

C. I. Acid Red 6, 8, 9, 13, 14, 1
8, 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. I. Acid Black 2, 48, 51, 52, 1
10, 115, 156, C.I. I. Reactive Yellow 2, 3, 17, 2
5, 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. I. Food black 1, 2

As the cationic dye used as a component of the ink constituting the ink set of the present invention, existing ones or newly synthesized ones are usually used as long as they have appropriate color tone and density. Can be used. Further, any of these may be mixed and used. Specific examples of the cationic dye include the followings. 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, C.I. I. Basic Black 2, 8, Aizen Cathilon Black SBH, BXH, SH, AC
H, MH, TH (Hodogaya Chemical) Sumiacryl Black B, R, AP, BP, CP, FFP
(Sumitomo Chemical), Diacryl Supra Black GSL, RSL, ESL (Mitsubishi Kasei),

As the water-insoluble dye containing the disperse dye used as a component of the ink constituting the ink set of the present invention, those which are already on the market or those which are newly synthesized have appropriate color tone and density. Most of the dyes can be used, or a plurality of dyes can be mixed and used. Examples of the water-insoluble dye that can be used in the present invention include the followings.

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. Disperse Red 1, 4,
5, 7, 11, 12, 13, 15, 17, 30, 33,
43, 50, 52, 53, 54, 55, 56, 58, 5
9, 60, 65, 72, 73, 74, 75, 76, 8
2, 86, 88, 90, 91, 92, 96, 105, 1
06, 107, 110, 117, 118, 126, 12
7, 128, 131, 132, 134, 135, 13
6, 137, 140, 143, 145, 146, 151
s, 153, 159, 164, 167, 169, 17
7, 181, 184, 188, 190, 191, 20
0, 203, 205, 206, 221, 223, 22
4, 225, 227, 229, 239, 240, 25
8, 277, 278, 279, 283, 288, 30
2, 309, 311, 312, 323, 329, 33
2, 340, 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, 18
3, 185, 186, 189, 198, 200, 20
1, 205, 207, 214, 224, 225, 25
7, 259, 266, 268, 270, 284, 28
5, 287, 288, 291, 293, 301, 33
0, 332, 333, 337, 341, 345, 35
1, 352, 353,

C. I. Disperse Black 1, 9,
10, Black GL, Black B, Black
L, Black 2B, Black BT, Blac
kOBL, Black RSR, Black TK, B
black TG, Black S-CTL, Black
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-F
GB, Black S-SGN, Black S-WL
A, Black S-WLAT, Black B82,
Black BTNU82, Black 2BL, Bl
ack HR-FS, Black RB-FS, Bla
ckHG-FS, Black GB-FS, Black
KN-FS. The water-insoluble dye suitable in the present invention is not limited to those listed above.

The existing pigment or the newly synthesized pigment, which is preferably used as the coloring material component of the dispersion type ink used in the ink constituting the ink set of the present invention, is suitable for the ink. Most can be used as long as they have various colors and densities. Specifically, for example, inorganic pigments such as titanium-based, red iron oxide, aluminum powder, talc, clay, calcium carbonate, and silica; organic pigments such as carbon black, azo-based, phthalocyanine-based, quinacridone-based, cochineal, and safflower pigments. Etc.

In the at least one ink constituting the ink set of the present invention, the above-mentioned coloring material and amphoteric polymer compound, or a liquid medium for dissolving or dispersing the amphoteric polymer compound, is usually water and optionally water-soluble. Use a volatile organic solvent. Specific examples of the water-soluble organic solvent include, for example, amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; Ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6
Alkylene group alkylene glycols such as hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol; glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monoethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether Lower alkyl ethers of polyhydric alcohols such as ethanol;
Monohydric alcohols such as isopropyl alcohol; others, N-methyl-2-pyrrolidone, 1,3-dimethyl-
2-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide, 2-pyrrolidone,
Examples include cyclic amide compounds such as ε-caprolactam and imide compounds such as succinimide.

In general, the content of the water-soluble organic solvent is preferably 1 to 80% by weight based on the total weight of the ink,
More preferably, it is in the range of 3 to 50% by weight. Further, in order to adjust the pH of the ink constituting the ink set of the present invention to a predetermined value, ammonia water, alkali such as sodium hydroxide and potassium hydroxide, or acid such as acetic acid, carbonic acid and hydrochloric acid is appropriately used. In addition, the ink constituting the ink set of the present invention includes, in addition to the above components, a surfactant, a preservative, a rust preventive, an antioxidant, an evaporation accelerator, a chelating agent, a water-soluble polymer, and the like, if necessary. You may mix | blend an additive suitably.

Next, a method for producing the ink constituting the ink set of the present invention will be described. Since the ionicity of the amphoteric polymer compound changes depending on the isoelectric point, that is, the pH value in the liquid medium, the ionicity of the amphoteric polymer compound solution may be changed before adding the dye, depending on the ionicity of the dye used. Needs to be adjusted appropriately depending on the pH value. For example, in the case of using an anionic dye, the amphoteric polymer compound to be used is prepared by dissolving a previously used solvent, water and the like at a pH value equal to or higher than its isoelectric point and dissolving it to obtain an anionic polymer. Prepare as an electrolyte. Then, a dye is added and dissolved and mixed to prepare an ink. When a cationic dye is used, the amphoteric polymer compound to be used is dissolved in advance by adjusting the pH value below the isoelectric point of the solvent, water and the like to be used as a polyelectrolyte having a cationic property. Must be prepared.

When a pigment is used as a coloring material of the ink constituting the ink set of the present invention, it is necessary to prepare the pigment dispersion in advance. As the dispersant, an anionic polymer, a cationic polymer, an anionic surfactant, a cationic surfactant or the like is used. The dispersion processing is performed using a disperser such as a sand grinder. Also in this case, it is necessary to adjust the ionicity of the amphoteric polymer compound in advance according to the ionicity of the dispersion resin to be used by adjusting the pH value and dissolve it. For example, when a pigment dispersion is prepared by using an anionic polymer such as styrene-acrylic acid copolymer as a dispersant, the amphoteric polymer compound to be used is added to the solvent and the solvent before the addition of the pigment dispersion. It is necessary to adjust the pH value to the isoelectric point or higher in water or the like to prepare an anionic polymer electrolyte. An ink constituting the ink set of the present invention is prepared by mixing a pigment dispersion with the pH-adjusted polymer electrolyte.

The recording material used in the present invention is not particularly limited, and for example, conventionally used plain paper or the like is preferably used. In the present invention,
Not only preventing bleeding at the boundary of different colors, but also adding black dots (smearing) to the background and the like shows a sufficient effect, and a suitable image is formed.

Next, the recording apparatus used in the present invention will be described. As an inkjet method and apparatus suitable for performing recording by using the ink set of the present invention, an inkjet recording in which thermal energy corresponding to a recording signal is applied to ink in a chamber of a recording head and droplets are generated by the thermal energy A method and an inkjet recording device are mentioned.

Next, an example of the ink jet recording apparatus of the present invention suitable for recording using the above-mentioned ink of the present invention will be described below. FIGS. 1, 2 and 3 show examples of the configuration of a head which is a main part of the apparatus. Head 13
A glass, ceramic, or plastic plate having a groove 14 through which ink passes, and a heating head 1 used for thermal recording
5 (thin film head is shown in the drawing, but not limited to this). The heating head 15 has a good heat dissipation property such as a protective film 16 made of silicon oxide, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 made of nichrome, a heat storage layer 19, and alumina. It consists of a substrate 20.

The ink 21 has a discharge orifice (fine hole) 2
2, and the meniscus 23 is formed by the pressure P. Now, when electrical signal information is applied to the aluminum electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly heats up, and bubbles are generated in the ink 21 in contact with the area, and the pressure causes The meniscus 23 protrudes, the ink 21 is ejected and becomes an ink droplet 24, which is ejected from the ejection orifice 22 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 with reference to FIG. FIG. 1 is a cross-sectional view of the head 13 along the ink flow path.
FIG. 2 is a sectional view taken along line AB in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating the above 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 a recording area of the recording head 65, and in the present example, is held in a form protruding into the movement path of the recording head 65. Reference numeral 62 denotes a cap on the ejection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, contacts the ink ejection port surface, and performs capping. Is provided. Further, an ink absorber 63 is provided adjacent to the blade 61 and is held in a form protruding into the movement path of the recording head 65, similarly to the blade 61.

The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery section 64, and the blade 61 and the ink absorber 63 remove water, dust, and the like from the ink ejection port surface. A recording head 65 having ejection energy generating means for ejecting ink to a recording material facing an ejection port surface provided with ejection ports to perform recording;
Reference numeral 6 denotes a carriage for mounting the recording head 65 and moving the same.

The carriage 66 slidably engages with a guide shaft 67, and a part of the carriage 66 is connected (not shown) to a belt 69 driven by a motor 68. 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 these configurations, the recording material is fed to the position facing the ejection port surface of the recording head 65, and is ejected to the ejection section provided with the ejection roller 53 as the recording progresses.

In the above structure, when the recording head 65 returns to the home position after recording is completed, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected into the movement path. There is. 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 in the same positions as the above wiping positions. As a result, the ejection port surface of the recording head 65 is also wiped during this movement. The movement of the print head 65 to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at the home position adjacent to the printing area at a predetermined interval while the printing head 65 moves through the printing area for printing. And the wiping is performed with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge 45 in which ink is supplied to the head via an ink supply member, for example, a tube. Where 4
Reference numeral 0 denotes an ink storage unit that stores the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip of the ink storage unit. By inserting a needle (not shown) into this stopper 42, the ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives the waste ink.
It is preferable for the present invention that the ink container has a surface in contact with the ink made of polyolefin, particularly polyethylene.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, but is preferably one in which they are integrated as shown in FIG. Used. In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage unit storing ink, for example, an ink absorber is stored, and a head unit having a plurality of orifices in which the ink in the ink absorber is stored. It is configured to be ejected from 71 as ink droplets.

It is preferable for the present invention to use polyurethane, cellulose or polyvinyl acetal as the material of the ink absorber. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head shown in FIG. 4, and is detachable from the carriage 66.

In the ink jet recording apparatus used in the present invention, the ink jet recording apparatus in which thermal energy is applied to the ink to eject the ink droplets has been described above as an example. Other inkjet recording devices such as the piezo system used can be used in the same manner.

When the ink jet recording method of the present invention is carried out, for example, a recording device in which four recording heads shown in FIG. 3 are arranged on a carriage is used. FIG.
Is an example. Recording heads 81, 82, 83, and 84 respectively eject inks of yellow, magenta, cyan, and black colors. The recording head is arranged in the recording apparatus described above and ejects ink of each color according to a recording signal. In addition, in FIG.
However, the present invention is not limited to this, and as shown in FIG.
Magenta, cyan, and black are also preferable examples when recording is performed by dividing the ink flow path.

[0051]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and% are based on weight unless otherwise specified. Examples 1 to 4 First, production of the inks of Examples 1 to 4 will be described.
Among the components of the following examples, dyes (for example, Example 1
In the case of C.I. I. Direct Yellow 86 and C.I.
I. The composition except Basic Black 8), that is, the amphoteric polymer, the solvent, water and the like are mixed and dissolved. At this time, the pH is adjusted to a predetermined value using a pH adjusting agent such as ammonia water, and the mixture is dissolved. After the polymer and the like are completely dissolved, the dye is added little by little to the solution, and the dye is mixed and dissolved until the dye is completely dissolved. After that, a membrane filter with a pore size of 0.22 μm (trade name: Fluoropore filter,
The inks of Examples 1 to 4 were obtained by pressure filtration using Sumitomo Electric Co., Ltd.). The pH was adjusted to 9.5 by using aqueous ammonia in Example 1, sodium hydroxide in Example 2 and lithium hydroxide in Example 3, and the pH was adjusted to 5.5 in Example 4. Since it was adjusted to dissolve the amphoteric polymer, hydrochloric acid was used as a pH adjuster.

[Ink Component of Example 1] (First Ink: Yellow) 4-Vinylpyridine-acrylic acid copolymer (Mw = 8,000) 5 parts Diethylene glycol 20 parts C.I. I. Direct Yellow 86 3 parts-Water 72 parts (second ink: black) -Polyallylamine hydrochloride (Mw = 3,000) 5 parts-Diethylene glycol 20 parts-C.I. I. Basic Black 8 3 parts Water 72 parts

[Ink Component of Example 2] (First Ink: Yellow) ・ Allylamine-styrenesulfonic acid copolymer 2 parts (Mw = 80,000) ・ Diethylene glycol 10 parts ・ Glycerin 5 parts ・ C. I. Direct Yellow 86 3 parts-Water 80 parts (second ink: magenta) -Polyamine sulfone hydrochloride (Mw = 2,000) 5 parts-Thiodiglycol 20 parts-C.I. I. Basic Red 14 3 parts ・ Water 72 parts

Ink Component of Example 3 (First Ink: Cyan) 2-Vinylpyridine-itaconic acid copolymer (Mw = 5,000) 1 part Diethylene glycol 35 parts C.I. I. Acid Blue 9 3 parts-Water 61 parts (Second ink: Black) -Polyallylamine acetate (Mw = 3,000) 5 parts-Diethylene glycol 30 parts-Astrazone Black ON 3 parts-Water 62 parts

[Ink Component of Example 4] (First Ink: Yellow) 2 parts allylamine-styrene sulfonic acid copolymer (Mw = 4,000) 2 parts diethylene glycol 5 parts glycerin C.I. I. Basic Yellow 11 3 parts-Water 80 parts (second ink: magenta) -Sodium polyacrylate (Mw = 3,000) 5 parts-Thiodiglycol 20 parts-C.I. I. Acid Red 35 3 parts ・ Water 72 parts

[Recording] Recording was performed on commercially available copy paper and bond paper by using the ink set using each ink obtained in Examples 1 to 4. [Evaluator] As the inkjet recording device used,
A recording apparatus similar to that shown in FIG. 4 was used to form a color image using the four heads shown in FIG. As the recording head used here, the same recording head as that used in BJC8200 (trade name, inkjet printer manufactured by Canon Inc.) was used. The drive conditions for the recording heads, that is, the conditions for energizing the heater were such that the applied voltage was 28 V, the pulse width was 3.2 μsec, and the drive frequency was 5 kHz for each head.

Comparative Example 1 A comparative first ink was prepared by removing the 4-vinylpyridine-acrylic acid copolymer from the first ink component of Example 1, and the second ink of Example 1 was prepared. A second ink for a comparative example was prepared by removing polyallylamine hydrochloride from the components. Using the ink set using the first and second inks, recording was performed on commercially available copy paper and bond paper as in Example 1.

[Evaluation] The printed matter of Examples 1 to 4 and Comparative Example 1 were evaluated for print density, bleeding, character quality (single color, mixed color) and water resistance, and the results are shown in Table 1. The evaluation methods were as follows. Printing density Alphanumeric characters and solid areas were recorded on commercially available copy paper and bond paper. After leaving for 1 hour, the print density was changed to Macbeth RD91.
5 (trade name, manufactured by Macbeth) and evaluated according to the following criteria. ◯: The print density of each color was 1.1 or more. Δ: The print density of each color was 1.0 or more and less than 1.1. X: The print density of each color was less than 1.0.

Bleeding The printed image is, as shown in FIG. 9, within a 1 cm square,
The quality of the bleeding image between the two colors was evaluated by the following evaluation criteria by dividing the image into 5 × 5 cells and printing solid images alternately with the two colors. Table 1 shows the results. (Evaluation Criteria) O: The boundary line between the two colors is clear, and no bleeding or color mixture is seen at the boundary. Δ: It is clear that there is a boundary line between the two colors,
Some bleeding and color mixing are seen at the boundary. X: The boundary line between the two colors is indistinguishable.

Character Quality Next, the monochromatic character quality and the mixed color character quality were evaluated.
The characters were composed of 1,500 alphanumeric characters and Chinese characters on A4 size high-quality paper, and the printing ratio was 100% for a single color and 200% for a mixed color of two colors. The evaluation criteria are as follows. Table 1 shows the results. (Evaluation Criteria) ◯: The edges of characters are clear and feathering and line thickening due to bleeding are not seen. Δ: The edges of the characters are slightly blurred and a uniform line thickening is observed. ×: Feathering is noticeable due to blurred edges of characters, and uneven line thickening is observed.

Water resistance of mixed-color portion It was recorded by staggered solid printing of two inks on commercially available copy paper and bond paper. After left for 1 hour, the print density is measured by Macbeth RD915. Thereafter, the printed matter was immersed in a container filled with water for 5 minutes, then left to dry and the printing density was measured again, and the residual rate of the printing density was determined from the following formula to evaluate the water resistance. The evaluation was based on the following criteria. Residual rate of print density = (print density after water resistance test / print density before water resistance test) × 100 ◯: The residual rate of print density of each color is 75% or more. Δ: The residual ratio of the print density of each color is 60% or more and less than 75%. X: The residual ratio of the print density of each color is less than 60%.

Table 1: Evaluation results

[0063]

As described above, according to the ink jet recording method using the ink set of the present invention, clear character quality without bleeding at the boundary between two different colors on the same recording material. It is possible to obtain a high quality color image.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a head 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.

FIG. 5 is a vertical sectional view of the ink cartridge.

FIG. 6 is a perspective view showing an example of a recording unit.

FIG. 7 is a perspective view showing a recording unit in which a plurality of recording heads used in the present invention are arranged.

FIG. 8 is a perspective view showing another recording head used in the present invention.

FIG. 9 is a bleeding evaluation pattern.

[Explanation of symbols]

 13: Head 14: Ink Groove 15: Heating Head 16: Protective Film 17: Aluminum Electrode 18: Heating Resistor Layer 19: Heat Storage Layer 20: Substrate 21: Ink 22: Discharge Orifice (Fine Hole) 23: Meniscus 24: Small Ink Droplet 25: Recording material 26: Multi-groove 27: Glass plate 28: Heating head 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed section 52: Paper feed roller 53: Paper ejection roller 61 : Blade 62: Cap 63: Ink absorber 64: Ejection recovery part 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head part 72: Atmosphere communication port 73: Substrate 81: Yellow 82: Magenta 83: Cyan 84: Black

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikio Sanada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (21)

[Claims] 1. An ink set comprising a plurality of types of ink containing a color material and a liquid medium for dissolving or dispersing the color material,
At least one of the plurality of kinds of ink contains an amphoteric polymer compound which is a copolymer of a monomer having an anionic group in the molecule and a monomer having a cationic group in the molecule. Ink set that is characterized. 2. The coloring material of at least one ink is an anionic dye, and the ink simultaneously contains the amphoteric polymer compound, and the coloring material of an ink different from the ink is a cationic dye, The ink set according to claim 1, wherein the ink contains a cationic polymer compound. 3. The coloring material of at least one ink is a cationic dye, the ink simultaneously contains the amphoteric polymer compound, and the coloring material of an ink different from the ink is an anionic dye, The ink set according to claim 1, wherein the ink contains an anionic polymer compound. 4. The anionic group contains at least one of a carboxyl group and a sulfone group.
Ink set described in. 5. The cationic group is an amino group, an imino group,
At least one of a pyrrolidone ring and an imidazole ring
The ink set according to claims 1 to 3, including one. 6. The ink set according to claim 1, wherein the amphoteric polymer compound has an isoelectric point. 7. The isoelectric point of the amphoteric polymer compound is pH = 3.
The ink set according to claim 6, which is in a range of 10 to 10. 8. The weight average molecular weight of the amphoteric polymer compound is
It is in the range of 1,000 to 1,000,000.
The ink set according to 1 to 3. 9. An ink jet recording method for recording on a recording material by ejecting ink droplets from an orifice according to a recording signal, wherein the ink is the ink set according to any one of claims 1 to 8. Inkjet recording method. 10. The ink jet recording method according to claim 9, wherein the ink is ejected by applying thermal energy to the ink. 11. A recording unit comprising an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein the ink is the ink set according to any one of claims 1 to 8. And a recording unit. 12. A head for ejecting ink droplets by applying thermal energy to the ink.
Recording unit described in. 13. The unit according to claim 11, wherein the ink containing portion is formed of polyurethane, cellulose, or polyvinyl acetate. 14. An ink cartridge having an ink containing portion containing ink, wherein the ink is
An ink cartridge according to any one of items 1 to 8. 15. The ink cartridge according to claim 14, wherein the ink container has a liquid contact surface formed of polyolefin. 16. An ink set according to claim 1, wherein the ink is an ink jet recording apparatus provided with a recording unit having an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets. An inkjet recording apparatus characterized by the following. 17. A head for ejecting ink droplets by applying thermal energy to the ink.
3. The ink jet recording apparatus according to claim 1. 18. The ink jet recording apparatus according to claim 16, wherein the ink containing portion is formed of polyurethane, cellulose or polyvinyl acetate. 19. An ink jet recording apparatus comprising: a recording head for ejecting ink droplets; an ink cartridge having an ink accommodating portion for accommodating ink; and an ink supply portion for supplying ink from the ink cartridge to the recording head. An ink jet recording apparatus, wherein the ink is the ink set according to claim 1. 20. The ink jet recording apparatus according to claim 19, wherein the recording head is a head that applies thermal energy to the ink to eject ink droplets. 21. The ink jet recording apparatus according to claim 19, wherein the ink containing portion has a liquid contact surface formed of polyolefin.