JPH10265725A - Aqueous ink, ink jet recording using the same ink and instruments therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain safe aqueous ink capable of improving water resistance of recorded materials without causing bleeding of recorded image and bleeding of mixed color by including a component A forming a water-insoluble complex with a dye, a component B solubilizing the complex and a component C absorbing the component B. SOLUTION: This ink contains a coloring material and a liquid medium, and at least contains (i) a dye such as an azo-based dye, (ii) a component A forming a water-insoluble complex with a dye, preferably a compound having an ionic property opposite to that of dye and (iii) a component B solubilizing a complex, preferably a nonionic water-soluble polymer and/or non-ionic surfactant and (iv) a component C absorbing the component B by outside stimulation, preferably a compound capable of heat reversibly dissolving or depositing from the aqueous solution at nearly transition temperature Ts (Ts is preferably 20-100 deg.C). Furthermore, ink jet recording is preferably carried out by using the above ink and retaining the surface temperature of a material to be recorded at Ts or above of the component C when recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention discharges and flies ink as a water-based writing instrument or as small droplets from a discharge port (orifice), and performs recording by attaching the small droplets to the surface of a recording material. The present invention relates to a water-based ink suitable for ink-jet recording, and more particularly to a water-based ink which gives high color development, reduces bleeding (feathering) of a recorded image, and is excellent in water resistance of printed matter, and an ink-jet recording method and equipment using the same. .

[0002]

2. Description of the Related Art Conventionally, aqueous inks used for writing instruments and the like are mainly water-based inks in terms of safety, odor and the like, and are composed of various water-soluble solvents, water-soluble dyes or pigments. In addition, ink jet recording inks are also easy to eject,
Aqueous inks are the mainstream in terms of safety and odor, and various water-soluble dyes or pigments are dissolved or dispersed in water or water and a water-soluble organic solvent, and if necessary, a humectant, a dye dissolution aid, An ink to which a fungicide and the like are added is known. The ink jet recording method can discharge several thousand drops of ink per second in response to an electric signal, and is capable of high-speed recording, low noise, easy colorization, and high resolution. It has many advantages such as the fact that it can record on plain paper, and its spread has been remarkable for several years.

[0003] Further, with the recent reduction in price and performance of personal computers, the standardization of GUI environments, and the spread of multimedia, the use of full color, high color development and high robustness in image recording with an ink jet printer or the like as a peripheral device. There are increasing demands for recording performance (water resistance), high-resolution recording, and high-speed recording, and various technical means for improving the color resistance and contrast and improving the water resistance of recorded matters have been proposed.

As a first example, Japanese Patent Publication No. 57-317 is disclosed.
No. 58, an ink containing a fluorine-containing solvent, an anionic dye and a cationic surfactant, or a modified dye that is synthesized from a cationic dye and an anionic surfactant and is soluble in these solvents is disclosed. As a second example, a water-soluble dye having an acidic group in the molecule and forming a salt with a basic organic compound or a basic lithium compound is disclosed in JP-B-63-7956. An ink comprising a compound and a liquid medium in which the compound is dissolved or dispersed is described.

Further, as a third example, Japanese Patent Application Laid-Open No. 58-32
No. 676 discloses salt formation of an acid dye and / or a direct dye with an ethylene oxide addition type cationic surfactant,
An aqueous ink solubilized with an organic solvent has been proposed,
As a fourth example, Japanese Patent Laid-Open No. 2-29678 discloses that
A water-based ink composition comprising a polyamine having a primary amino group, an anionic dye and a stability imparting agent and improving the water resistance of printed matter has been proposed.

As a fifth example, Japanese Patent Application Laid-Open No. Hei 6-2401 describes
No. 91, by using a water-based ink containing a colorant and solubilized at a pH of 10 or more of a polymer double salt formed from an anionic polymer and a cationic polymer, after recording, the polymer double salt is used. Describes that a tough film is formed and the water resistance of the recorded matter is improved.

[0007]

However, in the first conventional example described above, the problem of sticking of the ink droplets to the nozzle due to the volatilization of the fluorine-based solvent and the safety to the human body and the environment due to the use of the non-aqueous solvent. is there. Further, in the second example, since a polar solvent is used, there is no affinity for cellulose fibers as a constituent component of plain paper or the like, and a problem of feathering of a recorded image occurs. Further, when an amine is used as the basic organic compound, the odor of the ink becomes a problem, and since the ink is strongly basic, the skin is damaged and the members of the ink jet recording head are corroded. Can not stand.

In the third example, since a dye is once formed into a salt, a large amount of a surfactant is contained in the ink, and feathering of a recorded image occurs. In addition, since the salt is solubilized and solubilized, the recorded matter has poor water resistance. Furthermore, there is a problem in dissolution stability, and even when applied to ink jet recording, clogging of minute nozzles of the recording head may be caused.

In the fourth example, a salt-forming reaction between a polyamine and a dye is prevented by a stability-imparting agent such as urea. However, urea is a thermally decomposable compound. As a result, the dissolution stability is lost, and precipitation of the dye in the ink occurs.

Further, in the fifth example, since the ink becomes a highly basic liquid having a pH of 10 or more, the constituent members of the recording head are corroded, and a volatile basic compound is used. The pH drops due to the volatilization of the solubilized material, causing nozzle clogging of the recording head. Further, in addition to the ionic reaction between the anionic polymer and the cationic polymer, the reaction between the anionic dye and the cationic polymer also occurs at the same time, and the constituents of the ink such as the precipitation of the dye and the thickening of the liquid. Is poor in dissolution stability.

Therefore, an object of the present invention is to provide a safe and bleeding (feathering) or mixed color bleeding (bleeding) image.
And the water resistance of the recorded matter is improved, and when used in ink jet recording, high color development and high image quality water resistant without causing problems such as clogging of the ink jet recording head. Another object of the present invention is to provide an aqueous ink capable of providing a recorded matter having excellent properties, and an ink jet recording method and equipment using the same.

[0012]

The above object is achieved by the present invention described below. That is, the present invention provides an ink containing a coloring material and a liquid medium, wherein at least a dye, a component A that forms a water-insoluble complex with the dye, a component B that solubilizes the complex, and an external stimulus Aqueous ink comprising component C that adsorbs component B, and an ink jet recording method and apparatus using the same. More specifically, the component A is a compound having ionicity opposite to that of the dye, the component B is a nonionic water-soluble polymer and / or a nonionic surfactant, and C is
An aqueous ink, which is a compound that is dissolved or precipitated from the aqueous solution in a thermoreversible manner around the transition temperature (Ts), is preferable. With such a configuration, higher coloring of a recorded matter, reduction of feathering, and recording are achieved. An improvement in the water resistance of the product is achieved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. The aqueous ink of the present invention includes a coloring material and a liquid medium. First, the coloring material used in the present invention will be described. In general, an azo-based direct dye or a basic dye is used for the aqueous ink. Direct dyes have anionic properties because they have solubilizing groups such as sulfonic acid groups and carboxylic acid groups in the molecule.
The basic dye has a tertiary amine and a quaternary amine in the molecule, and has a cationic property. The ionic dye forms a complex with these surfactants if the ink contains an ionic or nonionic surfactant having a polarity opposite to that of the dye. For example, in the case of an anionic dye and a cationic surfactant, if the anionic dye D- (SO ₃ ⁻ ) _x is represented as C ⁺ and the cationic surfactant is represented as C ⁺ , these cause an ionic reaction as shown below. . As a result, the mutual ionicity of the dye and the surfactant is blocked, and the complex formed is almost insoluble in water. D− (SO ₃ ⁻ ) _x + xC ⁺ → D− (SO ₃ ⁻ −C ⁺ ) _x

In order to make the complex thus formed soluble in a solvent, in a conventionally known method, an excess of a surfactant is added or a solvent capable of dissolving the formed complex (generally, (A non-aqueous organic solvent) was contained in the ink. However, either of these methods
When used as a recording ink, there is a problem that excessive permeation of the recording material by a large amount of a surfactant or permeation of the recording material by an organic solvent causes feathering of the obtained recorded matter. Was.

Therefore, the present inventors have proposed that the above-mentioned known technique is as follows:
In any case, it is considered that there is a problem in that the complex is once formed and then solubilized, and by improving this point, the obtained recorded matter is of high quality without causing feathering and the like, and stands out. We have begun to develop recording inks that have water resistance. First, a nonionic water-soluble polymer aqueous solution having an EO (ethylene oxide) chain in a molecule was placed in a beaker, and a yellow anionic dye aqueous solution and a cationic surfactant aqueous solution were sequentially added thereto. A uniform liquid L was obtained without forming a complex. When this liquid was heated to about 100 ° C. and observed over time, precipitation of an insoluble colored substance gradually occurred. or,
Heating the beaker for several hours increased the amount of precipitated colorant, but the entire liquid was still colored.

From the above, it is clear that E is contained in the molecule in the ink.
When a nonionic water-soluble polymer having an O (ethylene oxide) chain is present, the ionicity of the anionic dye and the cationic surfactant is blocked by the ion-blocking action, but the blocking power is weakened by heating, Anion-
It is presumed that cation bonds occur and a complex formation reaction occurs. However, since the whole liquid was colored,
The ionic blockade is not completely unblocked.
That is, the above example shows that the ionic blocking effect on the dye or surfactant of the nonionic water-soluble polymer is partially released by external stimulus due to temperature.

Therefore, the present inventors have conducted intensive studies on substances and conditions capable of completely releasing the blocking action on ionicity in order to freely control the formation of a complex between the ionic dye and the surfactant. went. As a result, in a system in which a thermosensitive polymer aqueous solution that dissolves or precipitates from the aqueous solution thermoreversibly around its transition temperature (Ts) is added to the liquid L, the nonionicity is changed depending on the temperature conditions. Found that the ionic blocking action of water-soluble polymers can be completely released, and that all of the ionic dyes present in the solution are insoluble by forming a complex with the ionic surfactant. Thus, the present invention has been achieved. This phenomenon is caused by the coexistence of the temperature-sensitive polymer as described above, this substance has no binding property to non-ionic water-soluble polymer in liquid at room temperature, but becomes non-ionic by thermal stimulation. Water-soluble polymer can be adsorbed and further insolubilized at a temperature higher than the transition temperature Ts of the temperature-sensitive polymer, so that the nonionic water-soluble polymer is precipitated and removed from the liquid system, and the dye etc. It is considered that the blocking effect on the ionicity of is completely released.

That is, at least a dye, a component A for forming a water-insoluble complex with the dye, a component B for solubilizing the complex, and a component C capable of adsorbing the component B by an external stimulus are contained in the ink. If they coexist, it is possible to freely control the formation of the complex by controlling the external stimulus, and it is possible to further improve the coloration and feathering of the obtained recorded matter and improve the water resistance of the recorded matter. Can be achieved.

The present inventors have extensively searched for a material corresponding to the component C having the above-mentioned effects, and found that the material has temperature sensitivity, is water-soluble, and has a transition temperature of (usefulness as an ink). A series of thermosensitive polymeric substances at 20-100 ° C (considering) have been found. Specific examples of such a temperature-sensitive polymer that can be used in the present invention include a vinyl carboxylic acid ester monomer (a) of an alkylene oxide adduct of an active hydrogen compound having a nitrogen-containing ring; A copolymer containing at least 50% by weight of a total of at least one kind of the monomer (b) represented by the following general formula (I) and (meth) acrylic acid is exemplified.

[0020] (In the above general formula (I), R ₁ is H or CH ₃ , R
₂ is a cyclic nitrogen-containing compound listed below, which is bonded by one N atom in the alkyl group or the substituent, and a substituted product thereof; In the general formula (I), n is 2 to 4, m is 2 to 4, and l is 2 to
4, x is 2 to 50, y is 0 or 1 to 50, z is 0 or 1
Excluding those in which n, m, and l are the same numbers, and those in which n and m or m and l are the same numbers. )

Hereinafter, in the present invention, a vinyl carboxylic acid ester monomer (a) of an alkylene oxide adduct of an active hydrogen compound having a nitrogen-containing ring, which is a material suitable for forming a temperature-sensitive polymer suitable for the component C, The monomer (b) represented by the general formula (I) will be described in detail. First, examples of the active hydrogen compound having a nitrogen-containing ring in the monomer (a) include a compound having a nitrogen-containing ring and an active hydrogen for addition of an alkylene oxide.
Examples include a nitrogen-containing alicyclic compound and a nitrogen-containing unsaturated cyclic compound.

Examples of the nitrogen-containing alicyclic compound include those having an aziridine ring such as aziridine and 2-methylaziridine, and those having a pyrrolidine ring such as pyrrolidine, 2-methylpyrrolidine, 2-pyrrolidone and succinimide. Piperidine, 2-methylpiperidine, 3,5-dimethylpiperidine, 2-ethylpiperidine, 4-piperidinopiperidine, 4-pyrrolidinopiperidine, those having a piperidine ring such as ethylpipecollinate, 1-methylpiperazine, Examples thereof include those having a piperazine ring such as 1-methyl-3-ethylpiperazine, those having a morpholine ring such as morpholine, 2-methylmorpholine and 3,5-dimethylmorpholine, and ε-caprolactam.

Further, as the nitrogen-containing unsaturated cyclic compound,
For example, 3-pyrroline, 2,5-dimethyl-3-pyrroline, 2-hydroxypyridine, 4-pyridylcarbinol, 2-hydroxypyrimidine and the like can be mentioned. Among these, those preferably used in the present invention are nitrogen-containing alicyclic compounds, and among them, more preferably,
Those having a piperidine ring and those having a morpholine ring, most preferably those having a morpholine ring.

The vinyl carboxylic acid ester monomer (a) preferably used for the material for forming the thermosensitive polymer is an ester of the above-mentioned alkylene oxide adduct of an active hydrogen compound having a nitrogen-containing ring with vinyl carboxylic acid. However, as the vinyl carboxylic acid used in this case, for example, methacrylic acid, acrylic acid, maleic acid, vinylbenzoic acid, and derivatives thereof are preferable, and particularly preferable is (meth) acrylic acid. And (meth) acrylic acid derivatives.

As the alkylene oxide in the monomer (a), ethylene oxide, propylene oxide, and butylene oxide adducts are preferred. The transition temperature (Ts) of the component C used in the present invention can be easily changed by adjusting the kind of the alkylene oxide and the number of moles added. For example, in the case of ethylene oxide, the transition temperature increases with an increase in the number of moles added, and in the case of propylene oxide or butylene oxide, the transition temperature decreases with an increase in the number of moles added. In the present invention, the addition mole number of the alkylene oxide is preferably 1 to 20 moles, more preferably 1 to 5 moles. For example, as the monomer (a), ethylene oxide and / or propylene oxide 1 of (substituted) morpholine
The transition temperature of a polymer having a (meth) acrylic acid ester as a constituent material of about 20 moles of an adduct can be easily adjusted by adjusting the type of alkylene oxide and the number of moles added.
In the case of an ethylene oxide adduct, the transition temperature increases from 36 ° C. to 76 ° C. as the number of moles added increases from 1 to 4. In the case of propylene oxide or butylene oxide adduct, the transition temperature decreases from 80 ° C. to 16 ° C. when the number of moles added is increased from 1 to 3.

Next, in the present invention, the above-mentioned general formula (I) which is a suitable material for forming a temperature-sensitive polymer as the component C is used.
The monomer (b) represented by the formula will be described. As the monomer (b), for example, a monomer having a structure in which an alkylene oxide is added to a vinyl (meth) acrylic acid monomer and a cyclic nitrogen-containing compound is added to a side chain terminal is used. As such, specifically, for example, ω-morpholino polyethylene glycol monoacrylate, ω-morpholino polyethylene glycol monomethacrylate, ω-piperidino polyethylene glycol monoacrylate, ω-piperidino polyethylene glycol monomethacrylate, ω-piperazino polyethylene glycol monoacrylate, ω-pyrrolidino polyethylene glycol monomethacrylate, ω-morpholino (poly) propylene glycol-polyethylene glycol monoacrylate, ω-morpholino (poly) propylene glycol-polyethylene glycol monomethacrylate, ω-morpholino (poly) butylene glycol-
Polyethylene glycol monoacrylate, ω-morpholino (poly) butylene glycol-polyethylene glycol monomethacrylate, ω-morpholino (poly) ethylene glycol- (poly) propylene glycol-polyethylene glycol monoacrylate, ω-morpholino (poly) ethylene glycol- (poly ) Propylene glycol-polyethylene glycol monomethacrylate,
ω-morpholino polybutylene glycol mono (meth) acrylate, ω-morpholino polytetramethylene glycol mono (meth) acrylate, and the like.

The monomer (b) represented by the above general formula (I)
As a method for synthesizing, for example, first, an alcohol or phenol having 1 to 4 carbon atoms is added to an alkylene oxide (for example, ethylene oxide, propylene oxide, or the like) at 50 to 200 ° C. and 1 to 10 atm in the presence of an alkali metal catalyst.
Polyether monool obtained by successive addition of butylene oxide and an alicyclic nitrogen-containing compound such as morpholine, followed by an addition reaction with methacrylic acid or acrylic acid or the like and an acidic catalyst (for example, sulfuric acid, para Esterification at 50 to 200 ° C. and 1 to 10 atm in the presence of toluenesulfonic acid or the like, or -10 to 50 together with an esterification reagent (eg, dicyclohexylcarbodiimide).
A method of performing an esterification reaction at a normal temperature and at a temperature of 0 ° C.

As described above, the temperature-sensitive polymer suitable as the component C composed of the above-mentioned materials includes the vinyl carboxylate monomer (a) and the monomer represented by the general formula (I). (B) It is a copolymer of (meth) acrylic acid (hereinafter abbreviated as AA). The temperature range of thickening changes depending on the composition ratio of these materials. , The monomer (a), the monomer (b) and the weight ratio of AA to monomer (a): monomer (b): AA = (50 to 9)
4): (40-5): (10-1), preferably, monomer (a): monomer (b): AA = (72-90): (2
0-8): (8-2).

In the aqueous ink of the present invention, the molecular weight and the amount of the polymer added as Component C in the ink are determined by
In the case of ink for ink jet recording, it is necessary to keep the ink viscosity within the allowable discharge range (100 mPa · s or less). Therefore, for example, as a temperature-sensitive polymer used for the component C, the weight average molecular weight is 1,000 or more and 50 or more.
It is advisable to use one with a range of 10,000 or less. That is, if the molecular weight of the temperature-sensitive polymer exceeds 500,000, the molecular chain becomes too long, and the re-dissolution rate is lowered, and the spinning property is not preferable. Further, in the present invention, even when polymers having different molecular weights are mixed and used, the effect can be sufficiently obtained.

Next, the component A used in the aqueous ink of the present invention
Will be described. The component A forms a water-insoluble complex with a dye as a coloring material in the ink, and a compound having ionicity opposite to the ionicity of the dye is preferably used. That is, as the component A, a substance having an action of ionically reacting with a coloring material such as a water-soluble dye and insolubilizing or coagulating and depositing the dye is used. For example, a cationic compound may be selected if the dye is anionic, and an anionic compound may be selected if the dye is cationic.

A dye having an anionic property generally has an acidic group such as —SO ₃ H and —COOH in a molecule. Since the anion / cation and the cation / anion complex are equilibrium reactions of the respective substances, for example, in a combination of anion / cation, a large excess amount of cation with respect to the anion becomes water-soluble, and in this case, water resistance Cannot be obtained. Therefore, there is an optimum value for the ratio of the amounts of the opposite ions, and it is necessary to control the ratio appropriately as to the target value of the water resistance of the obtained recorded matter.

Examples of the cationic compound which can be used in the present invention include quaternary ammonium sulfate, quaternary ammonium nitrate, aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium salt, benzethonium chloride, Alkylpyridinium salts, imidazolinium salts, polyallylamine salts, polyvinylimidazoline salts, polyaminoalkyl (meth) acrylate quaternary salts,
Examples thereof include polyaminomethylacrylamide quaternary salts, polyethyleneimine, cationized starch, chitosan acetate, and cationic dyes having the same hue as anionic dyes.

The anionic compounds usable in the present invention include organic acids, organic acid salts, organic acid esters,
Polycarboxylic acids, polycarboxylates and the like are typical,
Specifically, for example, p-toluenesulfonic acid, acetic acid,
Oxalic acid, maleic acid, tannic acid, sodium carboxylate, sodium alkyl phosphate, sodium alkyl sulfate, alkyl phosphate, alkyl sulfate, poly (meth) acrylic acid, sodium poly (meth) acrylate, sodium alkyl sulfonate And an anionic dye having the same hue as the cationic dye.

Examples of the anionic dye capable of forming a complex with the cationic compound include a direct dye, an acid dye, an edible dye, and a reactive dye. Since these have most of the hydrophobic dye skeleton and some acidic groups such as a sulfonate (—SO ₃ M) and a carboxylate (—COOM), they can be ionized with the above-mentioned cationic compounds. React to form a complex.

The following are specific examples of such an anionic dye. Examples of the black dye include C.I. I. Direct Black 17, C.I.
I. Direct Black 19, C.I. I. Dir
ect Black 62, C.I. I. Direct Bl
ack 154, C.I. I. Food Black 2,
C. I. Reactive Black 5, C.I. I.
AcidBlack 52, I.D. C. I. Project
t, Fast Black 2 and the like.

As the yellow dye, for example, C.I.
I. Direct Yellow 11, C.I. I. Dir
ect Yellow 44, C.I. I. Direct
Yellow 86, C.I. I. Direct Yellow
ow 142, C.I. I. Direct Yellow
330, C.I. I. Acid Yellow 3, C.I.
I. Acid Yellow 38, C.I. I. Disp
erse Yellow 3, C.I. I. Disperse
Yellow 5, C.I. I. Reactive Ye
llow 2 and the like.

As magenta dyes, for example, C.I.
I. Direct Red 227, C.I. I. IRE
ct Red 23, C.I. I. Acid Red 1
8, C.I. I. Acid Red 52, C.I. I. Dis
perse Red 60, C.I. I. Reactive
Red 3B and the like.

Examples of the cyan dye include C.I.
I. Direct Blue 115, C.I. I. Dir
ect Blue 168, C.I. I. Direct B
lu199, C.I. I. Acid Blue 9, C.I.
I. Acid Blue 40, C.I. I. Acid B
lue 74, C.I. I. Reactive Blue3
G and the like.

Further, other than these dyes, any of those having reduced water-solubilizing groups to increase water resistance, and those having special pH-sensitive solubility can be used. The concentration of the dye in the ink can be freely selected within the range of solubility, and is usually preferably 1 to 8 wt%. For recording on cloth, metal (alumite) or the like, 3 to 10 w%
t% is preferable, and 0.1% to 10% by weight is more preferable when the recorded image needs shading.

On the other hand, cationic dyes capable of forming a complex with an anionic compound include, for example, C.I.
I. Basic Yellow 11, C.I. I. Bas
icYellow 28, C.I. I. Basic Ora
nge 22, C.I. I. Basic Red 14,
C. I. Basic Violet 16, C.I. I. B
asic Blue 3, C.I. I. Basic Blu
e 41 and the like.

Next, components for solubilizing the cation / anion or anion / cation complex formed as described above will be described. As the component B used in the aqueous ink of the present invention, a nonionic water-soluble polymer and / or a nonionic surfactant are preferably used. Such a component B is a substance that blocks the ionicity of a dye or the like and allows coexistence of opposite ionic substances in one liquid, has an EO (ethylene oxide) chain in the molecule, and is itself Non-ionic. Specific examples of the nonionic surfactant and the nonionic water-soluble polymer include, for example, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl. Examples include phenyl ether sulfate and polyethylene oxide-polypropylene oxide block copolymer.

The water-based ink of the present invention having the above-described structure is provided with a humectant as described below in order to impart ink jet recording suitability such as control of reliability, storage stability or ink permeability. , A dissolution aid.
Examples of such a material include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. , 2,3-butanediol, 1,5-pentanediol, 1,7-heptanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, glycerin, diethylene glycol, triethylene Glycol, tetraethylene glycol, polyethylene glycol 200, dipropylene glycol, 2,2′-thiodiethanol,
Alkylene glycols such as 1,2,6-hexanetriol, monoethanolamine, diethanolamine,
Aprotic polar solvents such as alcoholamines such as triethanolamine, dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, and 1,3-propanesultone; 1,2-dimethoxyethane;
1,2-diethoxyethane, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ethyl ether, 1-
Lower alkyl ethers of polyhydric alcohols such as methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and tripropylene glycol monomethyl ether; formamide; -Pyrrolidone, N-methyl-2-
Pyrrolidone, 1,3-dimethylimidazolidinone, sorbitol, sorbitol, urea, 1,3-bis (β-hydroxyethyl) urea and the like. The content of the above materials in the ink is preferably in the range of 1 to 40% of the total weight of the ink.

When the aqueous ink of the present invention is used for ink jet recording, methanol, ethanol, propanol, 2-propanol, 1-butanol, 2-butanol,
When an alkyl alcohol such as butanol is contained, the ejection property is improved, which is more effective. These alcohols are preferably contained in the range of 1 to 10% of the total weight of the ink. Further, if necessary, additives such as a surfactant, a rust inhibitor, a fungicide, an antioxidant, and a pH adjuster can be contained.

The water-based ink of the present invention having the above-described structure can be used for a writing instrument. However, ink droplets are ejected from an orifice of a recording head in accordance with a recording signal to record on a recording material. It is particularly effective when used in an ink jet recording method to be performed. The ink jet recording method of the present invention is characterized in that the recording is performed by using the above-described aqueous ink of the present invention and maintaining the surface temperature of the recording material at or above the transition temperature Ts of the component C in the ink during recording. . Further, it is also a preferable embodiment to perform printing while maintaining the temperature of the ink at a temperature lower than the transition temperature Ts of the component C during printing. As the ink jet recording method used at that time, there are both a recording method in which mechanical energy is applied to ink to discharge droplets, and a recording method in which thermal energy is applied to ink to discharge droplets by foaming of ink. It is suitable.

Hereinafter, an ink jet recording apparatus suitably used in the present invention will be described. First, FIGS. 1, 2 and 3 show a configuration example of a head which is a main part of an ink jet recording apparatus using thermal energy. The head 1 includes a glass, ceramic, silicon or plastic plate having a flow path (nozzle) 2 through which ink passes, and a heating element substrate 3.
And obtained by bonding. The heating element substrate 3 includes a protective layer 4 formed of silicon oxide, silicon nitride, silicon carbide, or the like, an electrode 5 formed of aluminum, gold, an aluminum-copper alloy, or the like, and a high-melting material such as HfB ₂ , TaN, or TaAl. , A heat storage layer 7 made of thermally oxidized silicon or aluminum oxide or the like, and a substrate 8 made of a material having good heat dissipation properties such as silicon, aluminum, aluminum nitride or the like.

When a pulse-like electric signal is applied to the electrode 5 of the head 1, the area indicated by h of the heating element substrate 3 rapidly generates heat, and bubbles are generated in the ink in contact with the surface, The meniscus 10 protrudes by the generated pressure,
The ink is ejected through the nozzles 2 of the head, becomes small recording droplets 12 from the orifice 11, and flies toward the recording material 13. FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. FIG. 1 is a cross-sectional view of the head along the ink flow path, and FIG. 2 is a cross-sectional view taken along line XY 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 and fixed by a blade holding member, and forms a cantilever. The blade 61 is arranged at a position adjacent to the recording area of the recording head, moves in a direction perpendicular to the moving direction of the recording head, comes into contact with the ejection port surface, and performs capping. Further, 63 is a blade 61
Is an ink absorber provided adjacent to the blade 6
As in the case of No. 1, it is held in a form protruding into the movement path of the recording head. The blade 61, cap 62, absorber 6
The discharge recovery section 64 is constituted by 3, and the blade 61 and the absorber 63 remove water, dust and the like from the discharge port surface.

Reference numeral 65 denotes a discharge energy generating means,
A recording head 66 for performing recording by discharging ink onto a recording material facing a discharge port surface having discharge ports, and 66 is a recording head 65
Is a carriage for moving the recording head 65 by mounting the same. 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 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head,
As the recording progresses, the paper is discharged to a paper discharge unit provided with a paper discharge roller 53.

In the above-described configuration, when the recording head 65 completes recording and returns to the home position, the head recovery unit 64
Is retracted from the moving path of the recording head 65, while the blade 61 protrudes into the moving path.
As a result, the ejection openings of the recording head 65 are 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 positions at the time of the wiping described above. As a result, the ejection port surface of the recording head 65 is also wiped during this movement.

The above-described movement of the print head to the home position is not only at the end of printing or at the time of ejection recovery, but also at a predetermined interval while the print head moves through the printing area for printing. Position, and the wiping is performed along with the movement.

FIG. 5 is a diagram showing an example of an ink cartridge containing ink supplied to a recording head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink storage portion storing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof.
By inserting a needle (not shown) into the 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 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 also suitable for the one in which they are integrated as shown in FIG. Used for In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage unit for storing ink, for example, an ink absorber is stored, and ink in the ink absorber is transferred from a head unit 71 having a plurality of orifices to ink. It is configured to be ejected as drops. It is preferable for the present invention to use polyurethane as the material of the ink absorber. Further, a structure may be used in which the ink storage section is an ink bag in which a spring or the like is provided inside without using the ink absorber. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head shown in FIG. 3, and is detachable from the carriage 66.

Next, a description will be given of an ink jet recording apparatus of the type in which mechanical energy is applied to ink used in the ink jet recording method of the present invention to discharge liquid droplets to perform recording. The inkjet recording system includes a nozzle forming substrate having a plurality of nozzles, a pressure generating element made of a piezoelectric material and a conductive material disposed opposite to the nozzle, and an ink filling around the pressure generating element. And an on-demand ink jet recording head that displaces a pressure generating element by an applied voltage to discharge small droplets of ink from a nozzle.

FIG. 7 shows a configuration example of a recording head which is a main part of the recording apparatus. The head is an ink chamber (not shown)
, An orifice plate 81 for discharging ink droplets of a desired volume, a vibrating plate 82 for directly applying pressure to the ink, and a piezoelectric member joined to the vibrating plate 82 and displaced by an electric signal. It comprises an element 83 and a base 84 for supporting and fixing the piezoelectric element 83, the orifice plate 81, the diaphragm 82 and the like.

In FIG. 7, an ink flow path 80 is formed of a photosensitive resin or the like, and an orifice plate 81 is formed of a metal such as stainless steel or nickel. Are formed. Further, the vibration plate 82 is formed of a metal film such as stainless steel, nickel, titanium and the like and a high elastic resin film, and the piezoelectric element 83 is formed of a dielectric material such as barium titanate and PZT.

In the recording head having the above-described configuration, a pulse voltage is applied to the piezoelectric element 83 to generate a strain stress, and the energy deforms the vibration plate joined to the piezoelectric element, thereby causing the vibration in the ink flow path. The ink is vertically pressed, and the ink droplet is ejected from the ejection port 85 of the orifice plate to perform recording. Such a recording head is used by being incorporated in a recording apparatus similar to that shown in FIG. The detailed operation of the recording device may be the same as that described above.

[0057]

Next, the present invention will be described specifically with reference to examples and comparative examples. The composition ratio in the text is% by weight unless otherwise specified. Examples 1 to 6 (Preparation of Ink) The preparation of the ink of the example was performed according to the following procedure. 1. Adding an aqueous dye solution to the aqueous solution of component B, or
The aqueous solution of the component B is added to the aqueous solution of the dye and mixed with stirring. 2. A predetermined amount of the aqueous solution of the component A is added to the liquid (1) and mixed with stirring. 3. An aqueous solution of the component C is added to the liquid (2), followed by stirring and mixing. 4. Further, a solubilizing agent, a humectant and the like are added and mixed and stirred to complete the preparation process.

As the above component B, "Ionet FY-104" or "L" manufactured by Sanyo Chemical Industries, Ltd.
D7-CN "or" Newpole PE-74 "which is an EO-PO-EO block polymer. In addition, as the component A, when the dye was anionic, “Cation G-50” (trade name, manufactured by Sanyo Chemical Industries, Ltd.) was used.
Component C includes a monomer L1 represented by the following structural formula:
Composition of L1, L2, L3 (% by weight) of L2, L3 = 9
A 0: 2: 8 copolymer was used.

Table 1 below shows the ink formulations used in the examples and the physical properties of the obtained inks. Table 1: Examples 1 to
Ink composition of 6

COMPARATIVE EXAMPLES 1 TO 4 Examples 1, 3, 4 except that components A to C were not added.
Inks were prepared in the same manner and in the same manner as in Examples 5 and 5, and used as Comparative Examples 1-4. The components A to C were replaced with ion-exchanged water.

Evaluation [Evaluation Items] With respect to the inks of Examples 1 to 6 and the inks of Comparative Examples 1 to 4 obtained as described above, the performance as an ink was evaluated according to the following methods and evaluation criteria. 1. Optical density (OD value) A5 size paper with 5 mm square
Some patterns were printed, and the optical density of the print samples after 30 minutes or more had elapsed was measured. The density of five solid portions in the printed image was measured with a Macbeth reflection densitometer RD914, and the average value was taken as the OD value.
Note that the solid ink ejection amount is 12 nl / mm ² .

[0062] 2. Feathering (black ink only) Print the thinned dots on every other nozzle of the recording head on A4 size paper, observe the dots of the print sample after 30 minutes or more with a magnifying glass, and perform 5 steps based on the following criteria evaluated. 5: perfect circle dot 4: bleed or deformed in 1/4 of circumference 3: bleed or deformed in 1/2 of circumference 2: circumference 3/4 of which is blurred or deformed 1: dot with no circumference

3. Bleeding The evaluation pattern shown in FIG. 8 is prepared, the bleeding level is divided into five levels, and the bleeding level is defined as the line position where the mixed color blur occurs from the two-color boundary portion (arrow line). It was rated on a scale. That is, 1
The case where the bleeding was stopped within the dot line was designated as 5, and the lines up to which the bleeding occurred were designated as 4, 3, 2, and 1 hereinafter. In FIG. 8, part A is a print pattern of color A, and part B is a print pattern of color B different from color A.
The boundary between the two colors is indicated by a double-headed arrow line, and one dot line / 1
Five lines are recorded at intervals of the dot space.

4. Water resistance After the printed matter recorded in the evaluation item 1 was air-dried for 24 hours, immersed in a flat container filled with pure water for 1 minute, taken out and drained water, air-dried, measured OD again, and measured from the initial OD. Was calculated and the water resistance was evaluated. Water resistance (%) = OD value after immersion in water / initial OD value × 100

[Evaluator] BJC60 manufactured by Canon Inc. as a recording apparatus for evaluating ink jet recording of the above 1 to 4
0 (360 dpi) was used. The ink was supplied by a method of filling the target ink into a dedicated ink container. still,
The BJC 600 incorporates a mechanism for heating a sheet during recording. The outline is shown in FIG. The recording apparatus shown in FIG. 9 is different from the basic recording apparatus shown in FIG.
00 is set. The heating element 100 is a ceramic heater (250 nm in length) manufactured by Toshiba Corporation attached to the recording head, and the surface temperature of the heating element is measured using a temperature sensor (manufactured by KEYENCE).
TF2-31) Monitored by 200, PM by Kikusui Electronics
The temperature was controlled by PID control using the C35-2A power supply 201. As a result of the configuration described above, it is possible to heat the paper surface temperature in the range of 30 ° C. to 160 ° C. at an environmental temperature of 23 ° C.

In the evaluation, the paper surface temperature was higher than the transition temperature of the component C contained in the ink of each embodiment by +
Printing was performed by adjusting the heating element of the recording apparatus so as to reach a temperature of 10 ° C. When the transition temperature differs between the color inks of the respective colors, the highest transition temperature + 10 ° C. was set. The evaluation of the corresponding ink of the comparative example was also performed under the same conditions as those for recording with the ink of the example. [Evaluation Paper] As the evaluation paper for evaluation items 1 to 4, NP-SK paper for electrophotography (Lot No. OKK1) is used.
0) was used.

[Evaluation Results] Table 2 shows the performance evaluation results of evaluation items 1, 2 and 4 obtained by mounting the inks of Examples 1 to 6 on BJC600 and performing printing under the above conditions. Further, the same applies to the inks of Comparative Examples 1 to 4,
Table 2 shows the evaluation results. Further, the results of the bleeding of the evaluation item 3 are shown in Table 3 using the evaluation pattern of FIG. Table 4 similarly shows the bleeding evaluation results for the comparative examples.

Table 2: Evaluation results of OD, feathering and water resistance of Examples and Comparative Examples

Table 3: Bleeding evaluation results of Examples

Table 4: Bleeding evaluation results of comparative examples

From the results shown in Tables 3 and 4, the ink of the present invention has a high OD value, while maintaining good prevention performance against the occurrence of feathering and bleeding, while maintaining the water resistance of the image using the conventional ink. It turned out to be much better than if you had.

[0072]

As described above, according to the present invention,
In particular, in color recording on plain office paper such as electrophotographic paper, a printed matter having high image density, high color development and improved water resistance in which feathering and bleeding are effectively prevented can be obtained. Further, according to the present invention, since the above-described excellent printed matter can be obtained without using a special dye, the cost of ink can be reduced. Furthermore, according to the present invention, since the above-described excellent effects can be obtained by controlling the temperature of the ink and the recording material, the recording material can be applied to various recording materials such as a transparency film other than plain paper, cloth, and a metal plate. Good results are obtained for the surface p of the recording material.
This is useful because it is not affected by H or unevenness.

[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 example of a head having a plurality of nozzles of an ink jet recording apparatus.

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

FIG. 5 is a longitudinal sectional view showing an example of an ink cartridge.

FIG. 6 is a perspective view of a specification in which an ink jet recording head and an ink cartridge are integrated.

FIG. 7 is a longitudinal sectional view of an ink jet recording head using a piezoelectric element.

FIG. 8 is a bleeding evaluation pattern.

FIG. 9 is a perspective view showing an example of an ink jet recording apparatus provided with a heating element.

[Explanation of symbols]

 51: paper feed unit 52: paper feed roller 53: paper discharge roller 61: wiping member 62: cap 63: ink absorber 64: discharge recovery unit 65: inkjet recording head 66: carriage 67: carriage guide shaft 68: carriage drive unit 69: drive belt section 80: ink flow path 81: orifice plate 82: diaphragm 83: piezoelectric element 85: discharge port 100: heating element 200: temperature sensor 201: power supply for heating

Claims (10)

[Claims] 1. An ink containing a coloring material and a liquid medium,
An aqueous ink comprising at least a dye, a component A for forming a water-insoluble complex with the dye, a component B for solubilizing the complex, and a component C for adsorbing the component B by external stimulus. 2. Component A is a compound having ionicity opposite to that of the dye, component B is a nonionic water-soluble polymer and / or a nonionic surfactant, and
The aqueous ink according to claim 1, wherein the component C is a compound which is thermoreversibly dissolved or precipitated from the aqueous solution around its transition temperature (Ts). 3. The transition temperature Ts of component C is from 20 ° C. to 100 ° C.
The aqueous ink according to claim 2, wherein the temperature is ° C. 4. An ink jet recording method for performing recording on a recording material by discharging ink droplets containing a color material and a liquid medium from an orifice of a recording head according to a recording signal. An ink-jet recording method, characterized by using the ink described in any one of (1) and (2), and performing recording while maintaining the surface temperature of the recording material at or above the transition temperature Ts of the component C during recording. 5. The ink jet recording method according to claim 5, wherein the recording is performed while maintaining the temperature of the ink below the transition temperature Ts of the component C during the recording. 6. The ink jet recording method according to claim 4, wherein the recording is performed by applying thermal energy to the ink to discharge droplets. 7. The ink jet recording method according to claim 4, wherein the recording is performed by ejecting liquid droplets by applying a mechanical energy to the ink. 8. A recording unit comprising an ink storage section containing ink and a recording head section for discharging ink as ink droplets, wherein the ink is any one of claims 1 to 3. A recording unit, characterized in that: 9. An ink jet recording apparatus comprising a recording unit having an ink storage section for storing ink and a recording head section for discharging ink as ink droplets, wherein the recording unit used in the apparatus is according to claim 8. An ink jet recording apparatus characterized in that: 10. The ink jet recording apparatus according to claim 9, further comprising a mechanism for heating the recording material to a transition temperature Ts or higher in conjunction with the recording operation.