JP2000281951A - Ink, ink cartridge, recording unit, ink set, and method and apparatus for image recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink which gives an image excellent in resistances to scratch, markers, and water and which is excellent in delivery stabilty by incorporating a resin containing a colorant therein and a surfactant having ethylene oxide chains into the same. SOLUTION: A colorant is dissolved or dispersed in an oil-soluble solvent and then is emulsified in water. The resultant emulsion, together with a resin, is dissolved in a water-insoluble organic solvent and is subjected to phase inversion into an aqueous-phase emulsion, giving a microcapsuled cationic resin having an average particle size of 0.01-2.0 μm, preferably 0.05-1.0 μm, and containing the colorant. The microcapsuled cationic resin and a surfactant having at least 20 ethylene oxide chains, preferably 20-45 ethylene oxide chains, are dispersed in an aqueous medium containing 20-95 wt.% water and 2-60 wt.% water-soluble organic solvent, thus giving an ink having a surface tension of 15-60 dyn/cm, preferably 20-50 dyn/cm, a viscosity of 15 cP or lower, preferably 10 cP or lower, and a pH of 3-11, preferably 3.5-8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink which is suitable for ink jet recording, has excellent reliability, can provide a high image density even on plain paper, and has excellent water resistance and line marker resistance. , Ink set, ink cartridge, recording unit, image recording apparatus, and image recording method.

[0002]

2. Description of the Related Art An ink jet recording method is a method in which small ink droplets are made to fly and ink is attached to a recording medium such as paper to perform recording. In particular, JP-B-61-59911, JP-B-61-59912, and JP-B-61-59.
According to the ink jet recording method disclosed in Japanese Patent No. 914, that is, a method in which an electrothermal converter is used as a discharge energy supply unit and droplets are generated by applying thermal energy to ink to generate bubbles. A high-density multi-orifice of the recording head can be easily realized, and high-resolution and high-quality images can be recorded at high speed.

By the way, since a water-soluble dye is mainly used as a coloring material in the ink used in the ink jet recording method, a recorded image formed on plain paper by using these inks has a high water resistance and a low water resistance. Marker resistance may not be sufficient. On the other hand, with respect to the improvement of the water resistance of an image, for example, the following methods (1) to (4) are known. (1) A method of controlling the solubility of a water-soluble dye itself in water. (2) A method of adding various additives to a water-soluble dye. (3) A method in which an oil-based dye is used as a coloring material and used in a state of being dispersed in water. (4) A method in which a pigment is used as a coloring material and used in a state of being dispersed in water.

Further, as an ink for improving the water resistance of an image, Japanese Patent Application Laid-Open No. 03-172362 discloses an ink containing water, a colorant and a cationic emulsion as a fixing agent as essential components. Kaihei 08-23
No. 9610 discloses an ink containing pigment, a colored resin, and a humectant as essential components.

Further, when multi-color printing is performed by applying at least black ink and other color inks on a recording medium, for example, plain paper, the black ink applied on the recording medium and the color of another color are applied. It is known that so-called color bleed is likely to occur due to mixing of ink at the boundary with ink. As a method of reducing the color bleed between the black ink and the color ink, for example, the following methods (1) and (2) are known. (1) A method in which a pH-sensitive compound is contained in a black ink, and the color material in the black ink is caused to aggregate or precipitate due to a change in pH when mixed with the color ink. (2) A method in which the black ink contains a component that reacts with the component in the color ink and causes the black ink to increase the viscosity or agglomerate.

[0006] However, although each of the above-mentioned methods shows an excellent effect for solving each individual technical problem, it is possible to reduce the color bleed, and furthermore, to reduce the image density and water resistance in the black printing portion. Further, there is still room for improvement in obtaining a black ink which satisfies marker resistance and the like at a high level, as described below. That is, first, it is difficult to obtain an image with sufficiently improved water resistance by controlling the solubility of the water-soluble dye itself in water. Further, since the molecular weight of a portion that does not contribute to the color developing property of the dye is increased, the molecular extinction coefficient is substantially reduced, and the optical density (hereinafter abbreviated as OD) of the image and the color developing property may be reduced. Further, the marker resistance on plain paper may not be sufficient.

Also, a method of adding various additives to a water-soluble dye, for example, by adding a cationic activator or the like to form a salt of an anionic water-soluble dye, and then using the salt-forming dye together with a solvent which is easy to dissolve. In the method, the water resistance of the image is improved compared to the method of controlling the solubility of the dye itself in water as described above, but the anionic group which is a solubilizing group constituting the water-soluble dye and the additive are added. Due to the interaction of the cationic group, it may be difficult to obtain an image having a high optical density (OD) and excellent color development. Further, the marker resistance and the like of an image formed on plain paper are not sufficiently improved, and the stability of the ink itself may not be sufficient.
In the case of an ink using an oil-based dye as a coloring material,
In some cases, the color developability is inferior to ink using a water-soluble dye as a coloring material. In addition, according to the ink using a pigment, particularly carbon black, as a coloring material, an excellent water-resistant printed matter having a high optical density can be obtained, but a printed matter formed on plain paper using the ink has a high resistance. There is still room for improvement in scratch resistance and marker resistance.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 03-172362
As shown in JP-A No. 2-2, in an ink containing water, a colorant, and a cationic emulsion as a fixing agent as essential components, the fixing agent is used for improving scratch resistance and marker resistance of an image. If the amount of addition is increased, the viscosity of the ink increases, and if the amount of solids is low, the content of the colorant is relatively reduced, and there is a problem that a high image density cannot be obtained. In addition, in the case of an ink containing a pigment, a colored resin, and a humectant as essential components as disclosed in JP-A-08-239610, the degree of dyeing on the resin is low, so that the OD of an image is improved. Is not considered to be able to make a significant contribution.

As described above, when designing an ink jet pigment ink, in order to improve the scratch resistance and marker resistance of the obtained image, the amount of the pigment dispersant must be increased in the ink. However, on the other hand, this works as a factor that adversely affects storage stability, ejection stability, and the like. That is, as a method for improving the abrasion resistance and marker resistance, which are disadvantages of pigment ink, a technique of adding a resin to the ink is conventionally known. There is naturally an upper limit to the amount added. On the other hand, if the added amount of the resin is not sufficient, the effect of improving the scratch resistance and marker resistance cannot be obtained.
Also, the addition of the resin component reduces the amount of the coloring material contained in the ink, which may cause a decrease in the OD of a printed matter using the ink. Further, addition of the resin component often has a disadvantageous effect on the ejection stability of the inkjet ink. As described above, the addition of the resin to the inkjet ink affects the ink ejection stability and may lower the OD of the printed matter in some cases.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin-containing ink having excellent scratch resistance and marker resistance, and an ink having extremely excellent ejection stability. . Another object of the present invention is to provide an image having high image density and excellent abrasion resistance, water resistance, and marker resistance, and also have a very high ejection stability from a recording head when used in ink jet recording. An object of the present invention is to provide an ink which is excellent and which can extremely effectively reduce bleeding when performing multicolor printing.

Another object of the present invention is to provide an image recording method capable of stably forming an image having high image density and excellent scratch resistance, water resistance and marker resistance. It is in. Another object of the present invention is to provide high image density, excellent water resistance, scratch resistance, and marker resistance,
Another object of the present invention is to provide an image recording method capable of stably recording a multicolor image in which bleeding on a recording medium is extremely effectively reduced.

Another object of the present invention is to provide an image recording apparatus and an image recording apparatus capable of forming an image having high image density and excellent scratch resistance, water resistance and marker resistance extremely stably. An object of the present invention is to provide an ink, an ink set, an ink cartridge, and a recording unit that can be used.
Further, another object of the present invention is to provide an image recording apparatus having high image density, excellent scratch resistance, water resistance, and marker resistance, and capable of extremely stably forming a multicolor image with extremely little bleeding. It is another object of the present invention to provide an ink, an ink set, an ink cartridge, and a recording unit that can be used in the image recording apparatus.

Under the above-mentioned conventional technical background, the present inventors have found that in order to achieve the above-mentioned objects, particularly in designing ink suitable for ink jet recording, As a result of various studies on the addition of resin to the ink, the effect on the ink ejection stability can be suppressed as much as possible, or a resin addition technology to the ink that hardly affects the ink ejection stability The present invention has been found and has led to the invention described below.

[0014]

The above objects can be achieved by the present invention described below. That is, the present invention
An ink comprising a resin containing a colorant and a surfactant, wherein the surfactant has at least 20 or more ethylene oxide chains, an ink cartridge using the ink, and recording. unit,
An ink set, an image recording method, and an image recording apparatus.
That is, the ink cartridge of the present invention that can achieve the above object has an ink storage portion that stores an ink containing a resin containing a colorant and a surfactant having at least 20 or more ethylene oxide chains. It is characterized by having.

The recording unit according to the present invention, which can achieve the above object, contains an ink containing a resin containing a colorant and a surfactant having at least 20 or more ethylene oxide chains. An ink storage unit, a recording head, and a unit for supplying ink from the ink storage unit to the recording head are provided. An ink set that can achieve the above object is an ink set in which at least a first ink and a second ink are combined, wherein at least the first ink is a resin containing a colorant. And a surfactant having at least 20 or more ethylene oxide chains, and a first ink and a second ink.
Are inks having different colors selected from yellow, magenta, cyan, black, red, green, and blue, respectively.

An image recording method capable of achieving the above object is to apply an ink containing a resin containing a colorant and a surfactant having at least 20 or more ethylene oxide chains onto a recording medium. Characterized by a step of performing An image recording method capable of achieving the above object is a method of forming a multicolor image by applying at least first and second two-color inks on a recording medium using an ink jet recording method. And a resin having a cationic group in which a colorant is included as the first ink, and an ethylene oxide chain having at least 2
An ink containing a surfactant having 0 or more is used, and an ink containing a compound having an anionic group is used as the second ink.

An image recording apparatus which can achieve the above object is an ink containing a resin containing a colorant and a surfactant, wherein the surfactant has at least an ethylene oxide chain. An ink storage unit containing at least 20 inks, a recording head, and a recording unit including means for supplying ink to the recording head from the ink storage unit; and operating the recording unit to discharge ink from the recording head. And means for discharging. Further, an image recording apparatus capable of achieving the above object has an ink storage section and a recording head each storing a first ink and a second ink, and each of the recording heads from the ink storage section. A recording unit having a unit for supplying the first ink, and a unit for operating the recording unit to eject each ink from a recording head, and the first ink is colored. An ink containing a cationic resin containing an agent, a resin containing a colorant, and a surfactant having at least 20 or more ethylene oxide chains, wherein the second ink is an anionic ink. There is a feature.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. With the above-described configuration of the present invention, it is not clear why the ink is provided with excellent ejection stability while being a resin-containing ink having excellent scratch resistance and marker resistance, but the present inventors have as follows. I think it is. That is, when the periphery of the resin containing the coloring agent constituting the ink is coated with a surfactant having at least 20 or more ethylene oxide chains coexisting in the ink, the resin surface becomes more hydrophilic, for example, When used in thermal inkjet printing, it is possible to improve the wettability of the ink on the heater surface in the nozzles of the print head, which is thought to contribute to the improvement of the ink ejection stability. .

As described above, the ink of the present invention comprises a resin in which a colorant is included and a surfactant having at least 20 or more ethylene oxide chains. The constituent elements according to one embodiment will be described in the following order. (1) a resin containing a colorant (anionic resin,
(Cationic resin) (2) Surfactant having at least 20 or more ethylene oxide chains (3) Aqueous medium.

(1) Resin encapsulating the colorant Examples of the resin encapsulating the colorant include a microencapsulated resin in which the colorant is encapsulated in microcapsules made of the resin, and a resin dissolved in an oily solvent. Alternatively, a resin emulsion in which a dispersed dye or pigment or the like is dispersed in an aqueous medium may be mentioned. In particular, it is preferable to use a microencapsulated resin containing a colorant.

That is, for example, when a hydrophobic colorant such as an oily dye or a pigment is used as a colorant to be encapsulated by a resin, the colorant is encapsulated by coating the periphery of the colorant with a resin. It is presumed that the microcapsule makes it easier for the colorant and the hydrophobic portion of the resin to interact with each other, so that the hydrophobic portion of the resin tends to be less likely to be oriented in an aqueous system. It is considered that such excellent effects can be obtained. When the inkjet ink containing the colorant-encapsulated resin as described above is ejected from an inkjet printer, when ejected, adhesion or deposition of the resin onto the water-repellent nozzle-formed surface of the inkjet head may occur. Since it is suppressed, it is expected that this can contribute to further improvement of the ejection stability of ink over a long period of time. Here, the microencapsulated resin containing the colorant is dissolved or dispersed in an oily solvent, and the colorant is emulsified and dispersed in water.
It is a resin dispersion obtained by microencapsulation by a conventionally known appropriate method.

In the above, as the colorant to be included in the resin, a water-insoluble colorant such as a pigment or an oil-soluble dye is preferably used. That is, the water-insoluble colorant is easy to produce a microencapsulated resin containing the colorant. Specific examples of such a water-insoluble colorant include, for example, carbon black and the like as a black (Bk) pigment. As the carbon black used here, for example, furnace method,
A carbon black produced by a channel method, having a primary particle diameter of 15 to 40 nm, a specific surface area of 50 to 300 m ² / g by a BET method, and a DBP oil absorption of 40 to 150.
ml / 100 g, volatile content 0.5-10%, pH value 2
Those having characteristics such as to 9 are preferably used.

Commercial products having such characteristics include:
For example, no. 2300, no. 900, MCF88,
No. 33, no. 40, no. 45, no. 52, M
A7, MA8, No. 2200B (above, manufactured by Mitsubishi Chemical), RAVEN 1255 (above, manufactured by Columbia), R
EGAL400R, REGAL330R, REGAL6
60R, MOGUL L (all made by Cabot), Co
lor Black FW-1, Color Blac
k FW18, Color Black S170, C
color Black S150, Prtex 3
5, Printex U (all manufactured by Degussa) and the like.

Further, as the oil-soluble dye, for example, the following dyes can be preferably used. C. I. Solvent yellow 1, 2, 3, 13, 19,
22, 29, 36, 37, 38, 39, 40, 43, 4
4, 45, 47, 62, 63, 71, 76, 81, 8
5, 86, etc. C. I. Solvent Red 8, 27, 35, 36, 3
7, 38, 39, 40, 58, 60, 65, 69, 8
1, 86, 89, 91, 92, 97, 99, 100, 1
09, 118, 119, 122 and the like. C. I. Solvent Blue 14, 24, 26, 34, 3
7, 38, 39, 42, 43, 45, 48, 52, 5
3, 55, 59, 67 and the like. C. I. Solvent Black 3, 5, 7, 8, 14, 1
7, 19, 20, 22, 24, 26, 27, 28, 2
9, 43, 45 and the like. Further, among various conventionally known water-soluble dyes, those obtained by exchanging their counter ions (usually sodium, potassium and ammonium ions) with an organic amine or the like can be used.

In the present invention, when preparing a resin containing a coloring agent, the resin can be appropriately selected from the various coloring agents mentioned above. For example, as described below, in the case of an ink in which a pigment is further contained in the ink as a coloring material, a colorant having the same color tone as those pigments in order to adjust or supplement the color tone of the pigment used. It is preferable to select Thereby, an ink that can further improve the density of the recorded image can be obtained. For example, when carbon black is used as a pigment to be further added as a coloring material, it is preferable to use carbon black also as a coloring agent included in the resin. Further, as the colorant included in the resin, two or more kinds of color materials selected from the above-mentioned colorants may be used. In this case, each color material may be separately included in the resin, or each color material may be included in the common resin.

Hereinafter, a method for producing a microencapsulated resin containing a colorant, which is suitable as a material constituting the ink of the present invention, will be described. First, the coloring agent as described above is dissolved or dispersed in an oily solvent, and then the oily solvent is emulsified and dispersed in water. Examples of the method of emulsifying and dispersing the oily solvent in which the colorant is dissolved or dispersed in water include a dispersion method using ultrasonic waves and a method using various dispersers and stirrers. At this time, if necessary, various emulsifiers and dispersants, and further, emulsifying or dispersing aids such as protective colloids may be used. As these emulsifiers or dispersing aids, anionic surfactants, nonionic surfactants and the like can be used in addition to high molecular substances such as PVA, PVP and gum arabic.

Next, the above emulsion is microencapsulated to obtain a microencapsulated resin. The method is as follows. A colorant and a resin are dissolved in a water-insoluble organic solvent (oil-based solvent). Phase inversion by phase inversion to emulsification, interfacial polymerization in which a polymerization reaction is caused at the interface between the organic phase and the aqueous phase to microencapsulate, a material that forms a wall only in the organic phase is dissolved or present A so-called In-Situ polymerization method for forming microcapsules, a coacervation method for forming a microcapsule by changing the pH, temperature, concentration and the like of an aqueous solution of a polymer to separate the dense phase of the polymer to form microcapsules. . After the microcapsules are formed by the above method, a step of removing the oily solvent is added.
The microencapsulated cationic resin containing the colorant obtained as described above, which constitutes the ink of the present invention, preferably has an average particle diameter of 0.01 to 2.0.
It is good to use those having a thickness of 0 μm, preferably 0.05 to 1 μm.

As the resin used in the above, a resin having a cationic group is particularly preferable, and examples thereof include a polymer of a monomer having a hydrophilic group and a monomer having a hydrophobic group and a salt thereof. Examples of the monomer having an anionic hydrophilic group generally include the following sulfonic acid monomers and carboxylic acid monomers, and in the present invention, these can be suitably used. Examples of the sulfonic acid monomer include styrene sulfonic acid and salts thereof, vinyl sulfonic acid and salts thereof, and the like. Examples of the carboxylic acid monomer include α,
β-ethylenically unsaturated carboxylic acid, α, β-ethylenically unsaturated carboxylic acid derivative, acrylic acid, acrylic acid derivative, methacrylic acid, methacrylic acid derivative, maleic acid,
Maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid derivatives and the like can be mentioned. Monomers as hydrophobic components include styrene, styrene derivatives, vinyl toluene, vinyl toluene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, butadiene, butadiene derivatives, isoprene, isoprene derivatives, ethylene, ethylene derivatives, propylene, propylene derivatives, acrylic acid And alkyl esters of methacrylic acid.

Further, as the salt, hydrogen, an alkali metal,
Onium compounds such as ammonium ion, organic ammonium ion, phosphonium ion, sulfonium ion, oxonium ion, stibonium ion, stannonium, iodonium and the like can be mentioned. Further, the polymer and its salt, polyoxyethylene group, hydroxyl group, acrylamide, acrylamide derivative, dimethylaminoethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, ethoxytriethylene methacrylate, methoxypolyethylene glycol methacrylate, vinylpyrrolidone, vinylpyridine , Vinyl alcohol and alkyl ether may be added as appropriate.

(2) Surfactant Having at least 20 Ethylene Oxide Chains As the surfactant suitably used in the present invention, any surfactant having at least 20 ethylene oxide chains may be used. , Polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene stearylamine,
Specific examples include those having 20 or more ethylene oxide chains such as polyoxyethylene. However, the present invention is not limited by these. Any surfactant having an ethylene oxide chain length of 20 or more may be used.
A value of about 0 is a preferable range for implementing the present invention. Further, those having 25 to 45 can be more preferably used. Even if the ethylene oxide chain of the surfactant used is longer or shorter than this, the effect of stabilizing the ejection of the resin containing the colorant, which is one of the effects of the present invention, may not be sufficient. .

(3) Aqueous Medium, Other Additives, etc. The ink of the present invention is obtained by dispersing the above-mentioned resin (1) containing the colorant therein, and further, pigments to be added as necessary. It is preferable that the ink is configured to be held in a state where the ink is held. The aqueous medium used at that time preferably contains at least water as a component thereof. The ratio of water to the total weight of the ink is, for example, 20 to 95% by weight, preferably 40 to 95% by weight, and more preferably 60 to 95% by weight.

The aqueous medium may contain a water-soluble organic solvent as described below. Suitable water-soluble organic solvents include, for example, alkyl alcohols having 1 to 4 carbon atoms (eg, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, etc.), ketone or keto alcohols (eg, amides such as dimethylformamide, dimethylacetamide, acetone, diacetone alcohol, etc.), ethers (eg, tetrahydrofuran, dioxane, etc.), polyalkylene glycols (eg, , Polyethylene glycol, polypropylene glycol, etc.) and alkylene glycols having an alkylene group containing 2 to 6 carbon atoms (for example, ethylene glycol, propylene glycol, butylene glycol, Ethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol, etc.), polyhydric alkyl ethers such as alcohols (e.g., ethylene glycol methyl ether,
Ethylene glycol ethyl ether, triethylene monomethyl ether, triethylene glycol monoethyl ether, etc.) N-methyl-2-pyrrolidone, 2-
Pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. The total amount of these water-soluble organic solvents in the ink is 2 to 60% by weight based on the total amount of the ink, and a more preferable range is 5 to 2% by weight.
Preferably it is 5% by weight.

Further, a particularly preferred water-soluble organic solvent for constituting the ink of the present invention is glycerin, and its addition amount is 2 to 30% by weight, more preferably 5 to 30% by weight in the ink.
~ 15% by weight is preferred. A more preferred water-soluble organic solvent is a mixed solvent containing glycerin and a polyhydric alcohol (for example, diethylene glycol and ethylene glycol). The mixing ratio of glycerin and other polyhydric alcohol is glycerin: other polyhydric alcohol. With alcohol 10:
It is preferable to set the range of 5 to 10:50. Other polyhydric alcohols used with glycerin include, for example,
Examples include diethylene glycol, ethylene glycol, polyethylene glycol, propylene glycol, and the like. These glycerin or a mixture of glycerin and a polyhydric alcohol can be used by further mixing with another water-soluble organic solvent.

The ink of the present invention having the above-described structure is particularly preferably used in an ink jet recording method for recording an image by ejecting the ink from a recording head by thermal energy or mechanical energy and attaching the ink to a recording medium. Can be In the case where the ink of the present invention is particularly suitable for use in ink jet recording, the surface tension of the ink at 25 ° C. is 15 to 60 d.
yn / cm, 20 to 50 dyn / cm, viscosity of 1
It is preferably adjusted to 5 cP or less, particularly 10 cP or less, and more preferably 5 cP or less. When the pH of the ink is 3
To 11, more preferably 3.5 to 8. As specific ink compositions that can achieve such characteristics, for example, various inks of Examples described later can be cited. The ink of the present invention contains, in addition to the resin containing the colorant and the surfactant, various additives such as a pH adjuster for imparting functionality and an antifungal agent. Is also good.

Further, the ink of the present invention may further contain a coloring material in addition to the coloring agent included in the resin described above. For example, in the case of an ink to which a pigment is added, the optical density of the obtained printed matter can be further improved. Further, since the ink of the present invention contains a cationic resin in which the colorant described above is included, in the case of a pigment ink, in particular, it is generally referred to as a weak point of the pigment ink. Also, remarkable improvements are seen in the scratch resistance and marker resistance of the image.

Here, as the pigment that can be contained as a coloring material in the ink of the present invention, conventionally known pigments such as carbon black and organic pigments can be used without any problem. In particular, in the case of preparing a Bk ink, it is preferable to use a self-dispersion type carbon black in which at least one kind of hydrophilic group is bonded to the surface of the carbon black directly or in association with another atomic group. That is, the use of self-dispersion type carbon black as the coloring material is particularly preferable because a dispersant for dispersing the pigment in the ink is not added or the amount of the dispersant can be significantly reduced. As the dispersant, for example, a conventionally known water-soluble polymer or the like can be used.When such an ink is used for ink jet recording, such a polymer precipitates on the ink ejection surface of the recording head, and the ink disperses. There is a risk of lowering the ejection stability of, but if the self-dispersion type carbon black as described above is used as a pigment, as described above, the content of such a polymer contained in the ink is set to zero, Alternatively, it can be significantly reduced. As a result, it becomes possible to further improve the ejection stability during ink jet recording.

Next, the self-dispersion type carbon black will be described in detail. The self-dispersion type carbon black is preferably ionic, and for example, anionically charged one can be suitably used. In the present invention, examples of the anionic charged carbon black include those in which a hydrophilic group as shown below is bonded to the surface of the carbon black. -COO (M2), -S
_{O 3 (M2), - PO} 3 H (M2), and -PO ₃ (M2) _2,
(In the above formula, M2 represents a hydrogen atom, an alkali metal, ammonium or organic ammonium.)

[0038] Among these, in particular, -COO (M2) or -SO ₃ carbon black was allowed charged (M2) to bind to anionic carbon black surface, because dispersibility is good in the ink, the It can be particularly preferably used for the ink of the invention. By the way, among the hydrophilic groups represented as “M2”, specific examples of the alkali metal include:
Examples include Li, Na, K, Rb and Cs,
Specific examples of the organic ammonium include, for example, methyl ammonium, dimethyl ammonium, trimethyl ammonium, ethyl ammonium, diethyl ammonium, triethyl ammonium, methanol ammonium, dimethanol ammonium, trimethanol ammonium and the like. Examples of a method for producing a self-dispersible carbon black that is anionically charged include, for example,
There is a method of oxidizing carbon black with sodium hypochlorite. By this method, a -COONa group can be chemically bonded to the surface of carbon black.

Next, the ink according to the second embodiment of the present invention includes, as the resin containing the colorant in the ink according to the first embodiment described above, for example, a resin having a cationic group. Is used. As the cationic group in the resin in which the colorant is included, for example,
N, N-dimethylaminoethyl methacrylate [CH _{2
= C (CH 3) -COO-} C 2 H 4 N (CH 3) 2 ], N, N-
Dimethylaminoethyl acrylate [CH ₂ = CH-C
_{OO-C 2 H 4 N (} CH 3) 2 ], N, N-dimethylaminopropyl methacrylate _{[CH 2 = C (CH 3)} -COO-C
_{3 H 6 N (CH 3)} 2 ], N, N-dimethylaminopropyl acrylate _{[CH 2 = CH-COO-C} 3 H 6 N (C
H ₃ ) ₂ ], N, N-dimethylacrylamide [CH ₂ ＣC
H-CON (CH _{3) 2],} N, N-dimethyl methacrylamide _{[CH 2 = C (CH 3)} -CON (CH 3) 2 ], N, N-
Dimethylaminoethyl acrylamide [CH ₂ ＣＨCH—
CONHC ₂ H ₄ N (CH ₃ ) ₂ ], N, N-dimethylaminoethyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CONH
_{C 2 H 4 N (CH 3} ) 2 ], N, = N-dimethylaminopropyl acrylamide _{[CH 2 CH-CONH-C 3} H 6 N (C
H ₃ ) ₂ ], N, N-dimethylaminopropyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CONH—C ₃ H ₆ N (C
H ₃ ) ₂ ].

When the ink according to the second embodiment further contains a pigment, conventionally known carbon blacks and organic pigments can be used without any problem. Particularly preferably, a self-dispersion type carbon black in which at least one kind of cationic hydrophilic group is bonded directly to the surface of the carbon black or in association with another atomic group can be used. A specific example will be described below.

(Cationically Charged Carbon Black) Examples of the cationically charged carbon black include those in which at least one selected from the following cationic groups is bonded to the surface of carbon black.

[0042]

As a method for producing the above-mentioned cationically charged self-dispersible carbon black having a hydrophilic group bonded thereto, for example, a method of bonding an N-ethylpyridyl group having the following structure is exemplified. To illustrate with an example:

[0044] A method of treating carbon black with 3-amino-N-ethylpyridium bromide. in this way,
Carbon black charged cationically by the introduction of a hydrophilic group on the surface of carbon black has excellent water dispersibility due to repulsion of ions, so that a dispersant or the like is added even when contained in an aqueous ink. Even if it is not, a stable dispersion state is maintained.

Incidentally, various hydrophilic groups as described above may be directly bonded to the surface of carbon black.
Alternatively, another atomic group may be interposed between the carbon black surface and these hydrophilic groups, and the hydrophilic groups may be indirectly bonded to the carbon black surface. Here, specific examples of the other atomic groups include, for example, a linear or branched alkylene group having 1 to 12 carbon atoms, a substituted or unsubstituted phenylene group, and a substituted or unsubstituted naphthylene group. . Here, examples of the substituent of the phenylene group and the naphthylene group include a linear or branched alkyl group having 1 to 6 carbon atoms. Specific examples of the combination of another atomic group and a hydrophilic group include, for example, -C
_{2 H 4 -COOM, -Ph-SO} 3 M, -Ph-COO
_{M, -C 5 H 10 NH 3} + etc. (where, Ph is a phenyl group) and the like.

In the ink of the present invention, two or more of the above-described self-dispersible carbon blacks may be appropriately selected and used as a coloring material of the ink. The amount of the self-dispersible carbon black in the ink is preferably in the range of 0.1 to 15% by weight, particularly 1 to 10% by weight based on the total weight of the ink. Within this range, the self-dispersion type carbon black can be maintained in a sufficiently dispersed state in the ink without or with a small amount of a dispersant.

In the ink of the present invention, not only the above-described self-dispersible carbon black containing a cationic group but also a pigment dispersion obtained by dispersing the above-mentioned conventionally known carbon black with a dispersant containing a cationic group is used. The body may be used. Examples of the cationic dispersant include those obtained by polymerization of a vinyl monomer, and examples of the cationic monomer constituting at least a part of the obtained polymer include salts of tertiary amine monomers and salts thereof. And quaternized compounds.

Such compounds include, for example, N,
N-dimethylaminoethyl methacrylate [CH ₂ ＣC
_{(CH 3) -COO-C 2} H 4 N (CH 3) 2 ], N, N-dimethylaminoethyl acrylate [CH ₂ = CH-COO
_{-C 2 H 4 N (CH 3} ) 2 ], N, N-dimethylaminopropyl methacrylate _{[CH 2 = C (CH 3)} -COO-C 3 H 6
N (CH _{3) 2],} N, N-dimethylaminopropyl acrylate _{[CH 2 = CH-COO-C} 3 H 6 N (CH 3) 2 ],
N, N-dimethylacrylamide [CH ₂ ＣＨCH—CO
N (CH ₃ ) ₂ ], N, N-dimethylmethacrylamide [C
_{H 2 = C (CH 3)} -CON (CH 3) 2 ], N, N-dimethylaminoethyl acrylamide [CH ₂ = CH-CONH
_{C 2 H 4 N (CH 3} ) 2 ], N, N-dimethylaminoethyl methacrylamide _{[CH 2 = C (CH 3)} -CONHC 2 H 4 N
(CH _{3) 2],} N, = N-dimethylaminopropyl acrylamide _{[CH 2 CH-CONH-C 3} H 6 N (C
H ₃ ) ₂ ], N, N-dimethylaminopropyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CONH—C ₃ H ₆ N (C
H ₃ ) ₂ ].

In the case of a tertiary amine, as a compound for forming a salt, hydrochloric acid, sulfuric acid, acetic acid and the like can be mentioned, and as a compound used for quaternization, methyl chloride, dimethyl sulfate, benzyl Chloride, epichlorohydrin and the like. Among them, methyl chloride, dimethyl sulfate and the like are preferable in preparing the dispersant used in the present invention. The above-mentioned tertiary amine salt or quaternary amine
A quaternary ammonium compound behaves as a cation in water, and under neutralized conditions, acidity is a stable dissolution region. The content of these monomers in the copolymer is preferably in the range of 20 to 60% by weight.

Other monomers used in the constitution of the cationic polymer dispersant include, for example, 2-hydroxyethyl methacrylate and acrylic acid having a hydroxy group such as acrylic acid ester having a long ethylene oxide chain in the side chain. Examples of hydrophobic monomers such as esters and styrene-based monomers and water-soluble monomers soluble in water near pH 7 include acrylamides, vinyl ethers, vinylpyrrolidones, vinylpyridines, and vinyloxazolines. As the hydrophobic monomer,
Hydrophobic monomers such as styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, alkyl esters of (meth) acrylic acid, and acrylonitrile are used. In the polymer dispersant obtained by copolymerization, the water-soluble monomer is used in an amount of 15 to 35% by weight so that the copolymer is stably present in an aqueous solution, and the hydrophobic monomer is a pigment of the copolymer. Is preferably used in the range of 20 to 40 wt.

In dispersing the pigment by using the above cationic water-soluble polymer as a dispersant, a pigment whose isoelectric point is adjusted to 6 or more, or a pigment whose isoelectric point is adjusted to 6 or more is preferable in terms of physical properties. A simple aqueous dispersion having a neutral or basic pH, for example, a pigment having a pH of 7 or more to 10 is preferable in terms of dispersibility. This is understood to be due to the strong ionic interaction between the pigment and the cationic water-soluble polymer.

In order to obtain an aqueous dispersion of fine particles of a pigment using the above materials, for example, carbon black is subjected to a premixing treatment in a cationic dispersant solution, followed by milling with a high shear rate dispersing apparatus. After dilution, centrifugation is performed to remove coarse particles. Thereafter, a material for a desired ink formulation is added, and an aging treatment is performed in some cases. Thereafter, an aqueous dispersion of carbon black can be obtained by performing centrifugal separation to finally obtain a pigment dispersion having a desired average particle size. The pH of the ink prepared in this way is 3 to 7
It is preferable to set it in the range.

The image recording method of the present invention is characterized in that ink is applied onto a recording medium using the ink of the present invention having the above-described structure. Is not particularly limited. For example, plain paper such as copy paper and bond paper, coated paper specially prepared for inkjet recording, glossy paper, OHP film, and the like are preferably used.

Next, an image recording apparatus according to the present invention, in which an image is recorded on a recording medium using the ink of the above-described embodiment, and members constituting them will be described. As a preferable example of the image recording apparatus, there is an apparatus that applies thermal energy corresponding to a recording signal to ink in a chamber of a recording head and generates droplets from the thermal energy. This will be described below.

(Recording Apparatus, Recording Method, etc.) The image recording apparatus of the present invention for recording an image on a recording medium using the ink of the present invention according to the first or second aspect, and an image using the same The recording method will be described. As an example of the image recording apparatus, there is an apparatus that applies thermal energy corresponding to a recording signal to ink in a chamber of a recording head and generates droplets from the thermal energy. This will be described below.

FIGS. 1 and 2 are schematic cross-sectional views of one embodiment of a head structure which is a main part of the image recording apparatus.
Specifically, FIG. 1 is a schematic sectional view of the head 13 along the ink flow path, and FIG. 2 is a sectional view taken along line AB in FIG. The head 13 has a flow path (nozzle) through which ink passes.
The heating element substrate 15 is obtained by bonding a glass, ceramics, silicon or plastic plate or the like having 14 to the heating element substrate 15. The heating element substrate 15 is made of silicon oxide, silicon nitride,
Protective film 16 formed of silicon carbide or the like, electrode 17 formed of aluminum, gold, aluminum-copper alloy, or the like
-1 and 17-2, a heating resistor layer 18 formed of a high melting point material such as HfB ₂ , TaN, TaAl, a heat storage layer 19 formed of thermally oxidized silicon, aluminum oxide, etc., silicon, aluminum, aluminum nitride, etc. The substrate 20 is formed of a material having good heat dissipation.

The electrodes 17-1 and 17- of the head 13
When a pulse-like electric signal is applied to the area 2, the area indicated by n on the heating element substrate 15 rapidly generates heat, bubbles are generated in the ink 21 in contact with the surface, and the meniscus 23 is protruded by the pressure. Then, the ink 21 is ejected through the nozzle 14 of the head, and the ink 21 is ejected from the ejection orifice 22 and flies toward the recording medium 25. FIG.
1 is an external view of an example of a multi-head in which a number of heads shown in FIG. The multi-head includes a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described with reference to FIG.
Is manufactured in close contact.

FIG. 4 shows an example of an ink jet recording apparatus incorporating the head according to the present invention. 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 disposed at a position adjacent to a recording area by the recording head.
It is held in a form protruding into the movement path of the recording head.
Reference numeral 62 denotes a cap on a protruding opening 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, abuts on the discharge opening surface, and performs capping. Is provided. Furthermore,
Reference numeral 63 denotes an ink absorber provided adjacent to the blade 61, which 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 unit 64, and the blade 61 and the ink absorber 63 remove moisture, dust, and the like from the ink ejection port surface.

Reference numeral 65 denotes a recording head which has discharge energy generating means and performs recording by discharging ink on a recording medium opposed to a discharge port surface provided with discharge ports, and 66 denotes a recording head on which a recording head 65 is mounted. Is a carriage for performing the movement. 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 medium, and reference numeral 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording medium is supplied to a position facing the discharge port surface of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as recording proceeds.

In the above configuration, when the recording head 65 returns to the home position at the end of recording or the like, the cap 62 of the ejection recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. I have. 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. Recording head 65
Moves from the home position to the recording start position,
The cap 62 and the blade 61 are located at the same positions as those at the time of 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 performed 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 to the home position adjacent to the printing area. Then, the wiping is performed along with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge containing ink supplied to the 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. 4
Reference numeral 4 denotes an absorber for receiving waste ink. Ink storage unit 4
As 0, it is preferable that the liquid contact surface with the ink is formed of polyolefin, particularly polyethylene.

(Recording Unit) The ink-jet recording apparatus used in the present invention is not limited to the above-described one in which the head and the ink cartridge are separated from each other, but one in which they are integrated as shown in FIG. Can also be suitably 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. 71
Are ejected as ink droplets from the ink. As the material of the ink absorber, it is preferable for the present invention to use polyurethane. Also, without using an ink absorber,
A structure in which the ink storage unit is an ink bag or the like in which a spring or the like is provided inside may be used. 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.

(Inkjet Recording Apparatus Using Piezoelectric Element / Recording Method) Next, as a preferable example of an inkjet recording apparatus utilizing mechanical energy, a nozzle forming substrate having a plurality of nozzles and a nozzle facing the nozzles are provided. A pressure generating element made of a piezoelectric material and a conductive material,
An on-demand ink jet recording head which includes ink filling around the pressure generating element, displaces the pressure generating element by an applied voltage, and discharges a small droplet of ink from a nozzle can be given.

FIG. 7 shows an example of a configuration 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 vibrating plate 82 which is displaced by an electric signal. It is composed of a piezoelectric element 83, an orifice plate 81, and a substrate 84 for supporting and fixing the diaphragm 82.

In FIG. 7, an ink flow path 80 is formed of a photosensitive resin or the like, and an orifice plate 81 has a discharge port 85 formed by electroforming or pressing a metal such as stainless steel or nickel. Reference numeral 82 denotes a metal film of stainless steel, nickel, titanium, or the like, a high elastic resin film, or the like, and the piezoelectric element 83 includes a dielectric material such as barium titanate or 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.
The energy deforms the vibration plate bonded to the piezoelectric element 83, vertically pressurizes the ink in the ink flow path 80, and applies ink droplets (not shown) to the ejection port 85 of the orifice plate 81
Such a print head which operates so as to perform printing by discharging more is used by being incorporated in an ink jet printing apparatus similar to that shown in FIG. The detailed operation of the ink jet recording apparatus may be performed in the same manner as described above.

(Ink Set) Incidentally, the ink of the present invention in the above-described embodiment contains carbon black and constitutes a black ink. This ink is a color ink containing a color material for yellow, A color ink containing a magenta color material, a color ink containing a cyan color material,
Suitable for forming a color image by combining with at least one color ink selected from a color ink containing a red color material, a color ink containing a blue color material, and a color ink containing a green color material. An ink set that can be used can be provided. In particular, when the black ink according to the present invention uses an anionic ink containing at least one of a water-soluble dye having an anionic group and a compound having at least an anionic group as an ink to be combined, the black ink on the recording medium is used. It was found that bleeding was extremely effectively suppressed, possibly due to an ion reaction occurring in the boundary region. As the water-soluble dye containing an anionic group used at that time, a conventionally known direct dye or acid dye can be used. or,
Examples of the compound having at least an anionic group include a conventionally known anionic surfactant, a polymer compound containing an anionic group, and the like. These also include a pigment dispersant and the like.

(Regarding each color ink) As a color material constituting the color ink that can be used in the above-mentioned ink set, a known dye or pigment can be used. As the dye, for example, an acid dye, a direct dye, or the like can be used. For example, as the anionic dye, existing dyes or newly synthesized dyes can be used as long as they have appropriate color tone and density. It is also possible to use a mixture of any one of these. Specific examples of the anionic dye and a solvent used when preparing the ink are described below.

(Coloring Material for Yellow) C.I. I. Direct Yellow 8, 11, 12, 27, 2
8, 33, 39, 44, 50, 58, 85, 86, 8
7, 88, 89, 98, 100, 110 C.I. I. Acid Yellow 1, 3, 7, 11, 17, 2
3, 25, 29, 36, 38, 40, 42, 44, 7
6, 98, 99 C.I. I. Reactive Yellow 2, 3, 17, 25,
37, 42 C.I. I. Food yellow 3

(Coloring Material for Red) C.I. I. Direct Red 2, 4, 9, 11, 20, 2
3, 24, 31, 39, 46, 62, 75, 79, 8
0, 83, 89, 95, 197, 201, 218, 22
0, 224, 225, 226, 227, 228, 229 C.I. 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. Reactive Red 7, 12, 13, 15,
17, 20, 23, 24, 31, 42, 45, 46, 5
9 C. I. Food Red 87, 92, 94

(Coloring Material for Blue) C.I. I. Direct Blue 1, 15, 22, 25, 4
1, 76, 77, 80, 86, 90, 98, 106, 1
08, 120, 158, 163, 168, 199, 22
6 C. I. Acid 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. Reactive Blue 4, 5, 7, 13, 1
4, 15, 18, 19, 21, 26, 27, 29, 3,
2, 38, 40, 44, 100

(Coloring Material for Black) C.I. I. Acid Black 2, 4, 8, 51, 52, 1
10, 115, 156 C.I. I. Food black 1,2

(Solvent) Examples of the solvent or dispersion medium that can be used in preparing the ink containing the coloring material for color ink as described above include water or a mixed solvent of water and a water-soluble organic solvent. Can be As the water-soluble organic solvent, those similar to those used when forming the ink of the present invention described above can be used. When these color inks are used by attaching them to a recording medium by an ink-jet method (for example, a bubble jet method), as described above, the ink may have a desired ink jetting property so as to have excellent ink-jet discharge characteristics. It is preferable to adjust so as to have viscosity and surface tension.

(Content of Coloring Material) Here, the content of the coloring material in each color ink is, for example, such that when the ink is used for ink jet recording, the ink has excellent ink jet discharge characteristics, The concentration may be appropriately selected so as to have a density. As a guide, for example, a range of 3 to 50% by weight based on the total weight of the ink is preferable. The amount of water contained in the ink is preferably in the range of 50 to 95% by weight based on the total weight of the ink.

(Recording Apparatus and Recording Method Using Ink Set) Next, when a color image is recorded by using the ink set including the ink of the present invention as described above, for example, A recording apparatus in which four recording heads shown in FIG. 3 are arranged on a carriage can be used. FIG. 9 shows an embodiment of the present invention.
Are recording units for ejecting yellow, magenta, cyan and black inks, respectively. The recording unit is disposed on a carriage of the recording apparatus described above,
Ink of each color is ejected according to the recording signal. FIG. 9 shows an example in which four recording units are used, but the present invention is not limited to this. For example, as shown in FIG.
A single recording head is attached to a recording head 90 having separate ink flow paths so that ink of each color supplied from the ink cartridges 86 to 89 containing the above four inks can be individually ejected. Can also be recorded.

[0076]

The present invention will be described below in more detail with reference to examples of the present invention. First, MC-1, MC-2, and MC-3 were prepared as a dispersion of a resin containing a colorant. <Preparation of MC-1> Materials having the following composition were mixed and dissolved. -Carbon black 5 parts by weight-Styrene-N, N-dimethylaminoethyl methacrylate copolymer (molecular weight 40,000) 20 parts by weight-Methyl ethyl ketone 30 parts by weight Phase inversion emulsification of the mixture obtained above using acetic acid as a neutralizing agent. Then, methyl ethyl ketone was removed to finally obtain an aqueous dispersion MC-1 having a microencapsulated resin having a solid content concentration of 20% by weight and an average particle diameter of 0.08 μm.

<Preparation of MC-2> The resin used in the preparation of MC-1 was replaced with a styrene-N, N-dimethylaminopropyl methacrylate copolymer (molecular weight: 35,000). Finally, an aqueous dispersion MC-2 having a microencapsulated resin having a solid content concentration of 20% by weight and an average particle diameter of 0.13 μm was obtained in the same manner as in the above.

<Preparation of MC-3> The following materials were mixed and dissolved.・ C. I. Solvent Black 35 parts by weight-Styrene acrylic acid (acid value 200, molecular weight 30,000) 20 parts by weight-Methyl ethyl ketone 30 parts by weight The above mixture was subjected to phase inversion emulsification using sodium hydroxide as a neutralizing agent to give methyl ethyl ketone. After removal, finally, an aqueous dispersion MC-3 having a microencapsulated resin having a solid content concentration of 20% by weight and an average particle diameter of 0.08 μm was obtained.

Examples 1 to 3 Using the dispersions prepared as described above, glycerin 8
Wt%, isopropyl alcohol 4.0 wt%, and
It was prepared such that the solid content in the ink of the microencapsulated resin containing the colorant was 8% by weight. Further, a surfactant was added thereto in the composition shown in Table 1 below, and water was added until the remaining amount became 100 wt%, to thereby prepare inks A to C of Examples 1 to 3. Table 1 shows the compositions of the inks A to C.

[0080]

Table 1: Composition of ink Here, POE (n) in Table 1 indicates that n polyoxyethylene chains (polyethylene oxide chains) are connected.

The three types of inks A, B, and C of Examples 1 to 3 obtained as described above were respectively mounted on a Canon color BJ printer BJF-800.
The cartridge was filled in a black ink tank of a J cartridge BC-60, and printing was performed on Canon PB paper by BJF-800 using a BJ-electrophotographic common paper manufactured by Canon. Then, each of the obtained printed matters was evaluated as follows.

The printed matter was evaluated according to the following method by the following method. Table 2 shows the results of these evaluations. (1) Image Density After printing a solid image for 12 hours, the image density was measured using a reflection densitometer Macbeth RD-918 (manufactured by Macbeth). The evaluation results were evaluated by classifying the image densities as follows. A: Image density is 1.30 or more B: Image density is 1.2 to 1.29 C: Image density is less than 1.2

(2) Water resistance The same solid image as used for the evaluation of the image density was used.
Leave for 2 hours. Then, the printed matter was allowed to stand in tap water for 3 seconds, and the reflection density after the water was dried was measured, and the residual ratio of the reflection density before and after the water resistance test was determined. Scale. The evaluation results were classified and evaluated as follows using this residual rate. A: Residual rate of image density is 90% or more B: Residual rate of image density is 70% or more and less than 90% C: Residual rate of image density is less than 70%

(3) Line Marker Resistance Using a yellow highlighter pen spot writer yellow manufactured by Pilot Co., one hour after printing the character, the character portion was marked once with normal writing pressure, and the marked portion was used. The pen tip of the pen was visually observed and evaluated. At this time, the line marker resistance was classified and evaluated as follows. A: No bleeding or stain on a white background is found on the printed matter, and the pen tip is not stained. B: No stain on the white background is found on the printed matter, but the pen tip is slightly stained. C: Printed matter Stains on white background

(4) Ejection Characteristics One solid pattern was written continuously in A4, and image defects were visually observed and evaluated according to the following criteria. A: Density non-uniformity, no non-ejection part B: No density non-uniformity, one non-ejection part, but the length is within 5 mm, acceptable for image C: Density non-uniformity, considerable non-ejection part, image Clearly recognized as a defect

[0086]

[Table 2] Table 2: Evaluation results

As is clear from Table 2, even when an image is formed on plain paper by using the ink of the present invention, the image density is sufficiently high, the water resistance and the line marker resistance are sufficiently high. Good and good discharge characteristics,
It was found that an effective ink was obtained as an ink for ink jet.

[0088]

As described above, according to the present invention,
For example, when ink-jet recording is performed on plain paper, it is possible to obtain an ink-jet print that can satisfy all of the following excellent characteristics. (1) High image density, (2) excellent water resistance, (3) excellent line marker resistance, and (4) excellent ejection characteristics.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AB in FIG. 1;

FIG. 3 is a schematic explanatory diagram of a multi-head.

FIG. 4 is a schematic perspective view showing one embodiment of an ink jet recording apparatus.

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

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

FIG. 7 is a schematic perspective view showing another configuration example of the ink jet recording head.

FIG. 8 is a schematic explanatory view of a recording head to which four ink cartridges are attached.

FIG. 9 is a schematic explanatory view showing a configuration in which four recording heads are arranged on a carriage.

[Explanation of symbols]

 13: Head 14: Ink groove 15: Heating head 16: Protective film 17-1, 17-2: Electrode 18: Heating resistor layer 19: Heat storage layer 20: Substrate 21: Ink 22: Discharge orifice 23: Meniscus 24: Ink Drop 25: Recording medium 26: Multi-groove 27: Glass plate 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Atmospheric communication port 80: Ink channel 81: Orifice plate 82: diaphragm 83: piezoelectric element 84: substrate 85: discharge port 86, 87, 88, 89: ink cart Ridge 90: Recording head 91, 92, 93, 94: Recording unit

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // C09C 1/48 B41J 3/04 102Z (72) Inventor Katsuhiko Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo KYA Within Non Co., Ltd. (72) Inventor Mikishi Ogasawara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Norinata Asagi 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. F term (reference) 2C056 EA13 FC02 2H086 BA02 BA55 BA59 4J037 AA02 CC02 CC12 CC13 CC15 CC16 CC17 CC25 CC29 DD07 DD17 DD23 DD24 EE06 EE28 EE43 FF05 FF09 FF18 FF25 4J039 AD01 AD02 AD03 BE09 AD10 AD12 BE33 CA06 EA15 EA16 EA17 EA19 EA20 EA36 EA38 EA44 EA47 FA02 GA24

Claims (14)

[Claims] 1. An ink comprising a resin containing a colorant and a surfactant, wherein the surfactant has at least 20 or more ethylene oxide chains. 2. The ink according to claim 1, wherein the resin is a resin having a cationic group. 3. The ink according to claim 1, wherein the surfactant is a nonionic surfactant. 4. The ink according to claim 1, further comprising a pigment as a coloring material. 5. The ink according to claim 4, wherein the pigment is carbon black. 6. The ink according to claim 5, wherein the carbon black is a self-dispersible carbon black. 7. An ink cartridge, comprising: an ink storage section that stores the ink according to claim 1. Description: 8. An ink storage section containing the ink according to claim 1 and a recording head, and means for supplying ink from the ink storage section to the recording head. A recording unit, comprising: 9. An ink set comprising a combination of at least a first ink and a second ink, wherein at least the first ink is the ink according to any one of claims 1 to 6. An ink set, wherein the first ink and the second ink are inks having different colors selected from yellow, magenta, cyan, black, red, green and blue, respectively. 10. The ink set according to claim 9, wherein the first ink is the ink according to claim 2, and the second ink is an anionic ink. 11. An image recording method, comprising the step of applying the ink according to claim 1 onto a recording medium. 12. An image recording method for forming a multicolor image by applying at least inks of first and second two colors on a recording medium by using an ink jet recording method.
3. An image recording method, wherein the ink according to claim 2 is used as the ink, and an ink containing a compound having an anionic group is used as the second ink. 13. An ink storage section containing the ink according to claim 1 and a recording head, and means for supplying ink from the ink storage section to the recording head. An image recording apparatus, comprising: a recording unit provided; and means for operating the recording unit to eject ink from a recording head. 14. An ink storage section containing a first ink and a second ink, a recording head, and means for supplying each ink of the recording head from the ink storage section. 7. A recording unit which is provided, and means for operating the recording unit to eject each ink from a recording head, and wherein the first ink is any one of claims 1 to 6. An image recording apparatus according to claim 1, wherein the second ink is an anionic ink.