JP2001164158A - Water base ink composition, ink cartridge, recording unit, ink jet recording equipment and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water base ink composition which gives high quality level images, particularly excels in intermittent discharge stability and does not cause attachment of a thickened substance of the ink to the surface of a discharge opening. SOLUTION: The water base ink composition comprises colorant-containing resin fine particles, pigment fine particles, and a polyhydric alcohol and, in addition, at least one of the compound represented by formula (I) and that represented by formula (II) (wherein R1 to R5 are each independently H, CH3 or C2H5). An ink cartridge, a recording unit and ink jet recording equipment and a recording method are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for ink jet recording and gives a high-quality image. The present invention relates to an aqueous ink composition, an ink cartridge, a recording unit, an inkjet recording apparatus, and an inkjet recording method that are particularly useful for inkjet recording in which occurrence of adhesion is suppressed.

[0002]

2. Description of the Related Art In an ink jet recording method, recording is performed by discharging ink and attaching the ink to a recording material such as paper. For example, Japanese Patent Publication No. 61-59911, Japanese Patent Publication No. 61-59912 and Japanese Patent Publication No.
No. 59914 or the like, that is, an ink jet recording method of discharging an ink by using an electrothermal converter as a discharge energy supply means and applying thermal energy to the ink to generate bubbles. Thus, it is possible to easily realize a high density multi-orifice of the recording head, and to record a high-resolution and high-quality image at a high speed. Such a scheme is
This is one of the mainstays of the ink jet recording method that is currently in practical use.

By the way, as an ink used in such an ink jet recording method, for example, an aqueous ink using a water-soluble dye as a coloring material is used. For this reason,
The recorded image thus formed is required to have even higher water resistance and improved line marker resistance on plain paper (hereinafter, simply referred to as marker resistance). In this field, particularly, To date, many means for improving the density and water resistance of a recorded image have been proposed. One of them is a technique of using a pigment as a coloring material and dispersing the pigment in water to obtain a pigment-dispersed ink. For example, a pigment-dispersed ink using carbon black as a coloring material can provide a recorded image having high image density and excellent water resistance. However, in such a recorded image, there is still room for improvement in scratch resistance and marker resistance particularly in an image formed on plain paper.

[0004] Further, the dispersion ink containing such a water-insoluble coloring material or resin may adversely affect the ejection stability of the ink jet, and particularly affect the intermittent ejection stability. Intermittent ejection failure means that, during printing, ink is ejected from a certain nozzle and then the ink is not ejected from that nozzle for a certain period of time (for example, about 30 seconds). This is a phenomenon in which stable ejection is not performed when the eye ink is ejected, and printing is disturbed.

[0005] Further, another problem in using such a dispersion-based ink containing a water-insoluble colorant or resin in an ink jet head is that an ink mist or the like adheres to an ink discharge port surface and causes a long time. If left unattended, the thickened material of the ink adheres to the ejection port surface, which may cause print misalignment or ejection failure.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such background art, and provides an image having high image density and excellent scratch resistance, water resistance and marker resistance. In addition, it is excellent in intermittent ejection stability from a recording head when used for ink jet recording, and further suppresses occurrence of printing failure due to adhesion of a thickened material of ink to a discharge port surface of the ink jet head and occurrence of ejection failure. An object of the present invention is to provide a water-based ink composition suitable for inkjet recording. Another object of the present invention is to provide an ink cartridge and a recording unit which can be used for forming an image having high image density and excellent scratch resistance, water resistance and marker resistance. . Still another object of the present invention is to provide an ink jet recording apparatus which has a high image density and provides an ink jet recorded image having excellent scratch resistance, water resistance and marker resistance. Still another object of the present invention is to provide an ink jet recording method capable of forming a high quality ink jet image having excellent scratch resistance on a recording material and also having excellent water resistance and marker resistance. I do.

[0007]

One embodiment of the aqueous ink composition capable of achieving the above object contains resin fine particles containing a colorant, pigment fine particles, and a polyhydric alcohol. An aqueous ink composition, further comprising at least one of a compound represented by the following general formula (I) and a compound represented by the following general formula (II): (R _{1 to} R ₅ in the above formula are each independently a hydrogen atom, CH
₃ and C ₂ H ₅ ).

[0008] The ink cartridge of the present invention, which can achieve the above object, has, for example, an ink storage section for storing the aqueous ink composition having the above-mentioned structure prepared for ink jet recording. It is characterized by the following. Further, a recording unit capable of achieving the above object is, for example, an aqueous ink composition containing resin fine particles containing a colorant, pigment fine particles and a polyhydric alcohol, and The aqueous ink composition containing at least one of the compound represented by the formula (I) and the compound represented by the general formula (II), which is prepared for inkjet recording, is housed therein. It is characterized by comprising an ink storage section and an ink jet head for discharging ink from the ink storage section.

An ink jet recording apparatus which can achieve the above object is, for example, an aqueous ink composition containing fine resin particles containing a colorant, fine pigment particles, and a polyhydric alcohol. And a water-based ink composition prepared for inkjet recording, characterized by containing at least one of a compound represented by the following general formula (I) and a compound represented by the following general formula (II). And an ink jet head for discharging ink from the ink container. (R _{1 to} R ₅ in the above formula are each independently a hydrogen atom, CH
₃ or C ₂ H ₅ )

An ink jet recording method capable of achieving the above object is, for example, an aqueous ink composition containing fine resin particles containing a colorant, fine pigment particles, and a polyhydric alcohol. And an aqueous ink composition prepared for inkjet recording, characterized by further comprising at least one of the compound represented by the general formula (I) and the compound represented by the general formula (II). And a step of applying to a recording material by an ink jet method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments. The present inventors have conducted intensive studies in order to solve the above-mentioned problems of the prior art, and as a result, at least one of the compound represented by the general formula (I) or the compound represented by the general formula (II) was contained in the ink. On the other hand, if the polyhydric alcohol is used together with the polyhydric alcohol, the recorded image obtained by such an ink shows a high image density, and the ink jet recording is performed without impairing image characteristics such as abrasion resistance, water resistance and marker resistance. When used for recording, the problem of intermittent ejection failure that occurs during inkjet recording, and the problem of adhesion of a thickened material of ink to the ejection port surface of an inkjet head, and other problems unique to inkjet recording have been solved. The inventors have found that an ink composition can be obtained, and have reached the present invention. The present inventors believe that the reason is as follows.

Generally, it is considered that intermittent ejection failure in an ink jet head is caused by an increase in ink viscosity caused when water evaporates from a nozzle, or by a film or solidification of an ink liquid surface at a nozzle tip. . In contrast, in the aqueous ink composition of the present invention, at least one of the compound represented by the following general formula (I) or the compound represented by the general formula (II) is used in combination with the polyhydric alcohol. As a result, the increase in ink viscosity when water evaporates from the nozzle, which is considered to be the cause of this intermittent ejection failure, and the occurrence of film formation and solidification of the ink surface of the ink at the nozzle tip are effectively suppressed. It is considered that intermittent ejection stability was realized.

[0013] (R _{1 to} R ₅ in the above formula are each independently a hydrogen atom, CH
₃ or C ₂ H ₅ ).

Further, in the aqueous ink composition of the present invention, at least one of the compound represented by the general formula (I) or the compound represented by the general formula (II) is combined with a polyhydric alcohol. However, according to such a configuration, when the ink that has not evaporated yet is added to the ink that has become thick and loses fluidity (“evaporated ink”) after the water content of the ink has been evaporated once. It has been found that the fluidity of the evaporated ink is easy to return to the original state, that is, the “evaporated ink” is easily dissolved again. From this, when the aqueous ink composition of the present invention having the above configuration is used for ink jet recording, in particular, adhesion of the thickened material of the ink to the ejection port surface of the ink jet head is minimized. As a result, it is considered that the occurrence of printing deviation and ejection failure can be effectively prevented.

The aqueous ink composition of the present invention contains fine resin particles containing a colorant, fine pigment particles, and a polyhydric alcohol, and further comprises a compound (I) represented by the general formula (I), Alternatively, at least one of the compounds (II) represented by the general formula (II) is contained. Hereinafter, each constituent material of the aqueous ink composition of the present invention having the above-described structure will be described in the following order (1) to (4). (1) Fine resin particles containing a colorant (2) Pigment (3) Compound (I) represented by general formula (I) or compound (II) represented by general formula (II) (4) Polyhydric alcohol

(1) Fine Resin Particles Containing Colorant First, the resin containing a colorant will be described. As the colorant-encapsulating resin encapsulating the colorant, for example, a resin in which the colorant is encapsulated in resin microcapsules, or a dye or pigment dissolved or dispersed in an oily solvent is dispersed in an aqueous medium. In particular, it is preferable to use a microencapsulated resin containing a coloring agent.

That is, for example, when a hydrophobic colorant such as an oil-based dye or pigment is used as a colorant, the colorant and the hydrophobic portion of the resin are liable to interact with each other by microencapsulation. It is presumed that the hydrophobic portion of tends to be hardly oriented in an aqueous system. as a result,
When the inkjet recording ink containing the colorant-containing resin is ejected from an inkjet printer, the adhesion and deposition of the resin on the water-repellent nozzle-formed surface of the inkjet head are suppressed, and the ink is ejected for a long period of time. It is expected that this can contribute to further improvement in stability.

A resin in which a colorant is microencapsulated is defined as a solution in which the above-mentioned colorant is dissolved or dispersed in an oily solvent, emulsified and dispersed in water, and further micro-encapsulated by a conventionally known appropriate method. A resin dispersion obtained by performing encapsulation.

As the coloring agent used at this time, a water-insoluble coloring agent such as a pigment or an oil-soluble dye is preferably used. That is, these water-insoluble colorants are easy to produce a resin in which the colorant is microencapsulated. Specifically, for example, carbon black or the like can be used as the black (Bk) pigment. Here, the carbon black is, for example, a carbon black produced by a furnace method or a channel method, and has a primary particle diameter of 15%.
-40 nm, specific surface area by BET method is 50-300 m
² / g, DBP oil absorption 40-150ml / 100g,
Those having characteristics such as a volatile content of 0.5 to 10% and a pH value of 2 to 9 can be preferably used.

Commercial products having such properties 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, Printex 3
5, Printex U (all manufactured by Degussa) and the like.

As the oil-soluble dye, the following dyes can be preferably used. C. I. Solvent Yellow 1, 2, 3, 13, 19, 22, 29, 36, 37, 3
8, 39, 40, 43, 44, 45, 47, 62, 6
3, 71, 76, 81, 85 and 86, etc. C. I. Solvent Red 8, 27, 35, 36, 37, 38, 3
9, 40, 58, 60, 65, 69, 81, 86, 8
9, 91, 92, 97, 99, 100, 109, 11
8, 119 and 122 and the like. C. I. Solvent Blue 1
4, 24, 26, 34, 37, 38, 39, 42, 4
3, 45, 48, 52, 53, 55, 59 and 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 and 45 etc. Further, among various conventionally known water-soluble dyes, those obtained by exchanging their counter ions (usually sodium, potassium or ammonium ions) with an organic amine or the like can be used.

As the various colorants described above, those having the same color tone as the pigment are preferably selected in order to adjust or supplement the color tone of the pigment described later. Thereby, the density of the recorded image can be further improved. For example, when carbon black is used as a pigment as described later, it is preferable to use carbon black also as a coloring agent included in the resin. Further, as the coloring agent included in the resin, two or more kinds of coloring materials selected from those described above may be used. In this case, each colorant may be separately included in a resin, or each colorant may be included in a common resin to prepare a colorant-containing resin.

Next, a method for producing a colorant-encapsulating resin in a mode in which the above-described colorant is microencapsulated will be described. First, the colorant as described above is dissolved or dispersed in an oily solvent, and then the oily solvent is emulsified and dispersed in water. In this case, as a method of emulsifying and dispersing the oily solvent in which the coloring agent is dissolved or dispersed in water, a dispersion method using ultrasonic waves, a method using various dispersers, and a stirrer are exemplified.
At this time, if necessary, various emulsifiers and dispersants, and also emulsifying or dispersing aids such as protective colloids can be used. As these emulsifiers or dispersing aids, PVA, P
In addition to high molecular substances such as VP and gum arabic, anionic surfactants and nonionic surfactants and the like can be used.

As a method for microencapsulation of the above-mentioned emulsion, a method of dissolving a colorant and a resin in a water-insoluble organic solvent (oil-based solvent) and then inverting the aqueous phase to emulsify the organic phase, An interfacial polymerization method in which a polymerization reaction is caused at an interface with an aqueous phase to form microcapsules, a material forming a wall only in an organic phase is dissolved or present to form microcapsules, a so-called In-Situ polymerization method,
A coacervation method or the like in which a concentrated phase of the polymer is phase-separated by changing the pH, temperature, concentration, etc. of the aqueous solution of the polymer to form microcapsules, and the like. After forming the microcapsules, a step of removing the oily solvent is added. The colorant-encapsulating resin obtained as described above has an average particle diameter of 0.01 to 2.0.
μm, more preferably 0.05 to
It is preferably in the range of 1 μm.

Examples of the resin include a copolymer of a hydrophilic monomer having a hydrophilic group and a hydrophobic monomer having a hydrophobic group, and a salt thereof. The monomer having an anionic hydrophilic group generally includes a sulfonic acid monomer and a carboxylic acid monomer. 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, and maleic acid. Acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid and fumaric acid derivatives.

Examples of the hydrophobic monomer 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, alkyl esters of acrylic acid, alkyl esters of methacrylic acid, and the like.

The salts of the copolymers of these hydrophilic monomers and hydrophobic monomers include, for example, alkali metal salts; ammonium salts, organic ammonium salts, phosphonium salts, sulfonium salts, oxonium salts, stibonium salts, and stannonium salts. Salts and onium salts such as iodonium salts, but are not limited thereto.
In addition, the copolymer and its salt, a polyoxyethylene group or a hydroxyl group may be introduced, or acrylamide, an acrylamide derivative, dimethylaminoethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, ethoxytriethylene methacrylate, Methoxy polyethylene glycol methacrylate,
Vinylpyrrolidone, vinylpyridine, vinyl alcohol, alkyl ether and the like may be appropriately copolymerized.

(2) Pigment As the pigment, conventionally known pigments such as carbon black and organic pigments can be used without any problem. When 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 via another atomic group. That is, when the self-dispersion type carbon black is used, 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, a conventionally known water-soluble polymer or the like is usually used. However, such a polymer may precipitate on the ink ejection surface of the inkjet recording head and reduce the ejection stability of the ink. There is. However, by using the above-described self-dispersion type carbon black as the pigment, the content of such a polymer in the ink can be made zero or significantly reduced. As a result, the ejection stability during inkjet recording can be further improved.

Next, the self-dispersion type carbon black suitable for the ink of the present invention will be described in detail. The self-dispersion type carbon black is preferably ionic, and for example, anionically charged one can be suitably used. Examples of the anionic charged carbon black include carbon black having the following hydrophilic groups bonded to the surface of the carbon black.

[0030] _{-COO (M2), - SO 3} (M2), - PO 3
H (M2) and -PO ₃ (M2) ₂ (where in the above formula, M2 represents a hydrogen atom, an alkali metal, ammonium or organic ammonium.)

[0031] Among them, -COO (M2) or -SO ₃ carbon black was allowed charged (M2) to bind to anionic carbon black surface, since the self-dispersibility is excellent in the ink, the It can be particularly preferably used in the invention.

By the way, specific examples of the alkali metal among those represented as "M2" in the above hydrophilic group include, for example, 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, monohydroxymethylamine, dihydroxymethylamine, trihydroxymethylamine, ethanolammonium, diethanolammonium and Triethanol ammonium and the like.

As a method for producing self-dispersible carbon black charged anionic, for example, there is a method of oxidizing carbon black with sodium hypochlorite.
ONa groups can be chemically bonded.

(3) Compound (I) represented by the following general formula (I) or compound (I) represented by the following general formula (II)
I): (R _{1 to} R ₅ in the above formula are each independently a hydrogen atom, CH
₃ or C ₂ H ₅ )

Typical examples of the compound represented by the above general formula (I) include ethylene urea (2-imidazolidinone),
Dimethylimidazolidinone and diethylimidazolidinone. A typical example of the compound represented by the general formula (II) is propylene urea. The amount of the ethylene urea compound represented by the above formula (I) or (II) in the ink may be 5 to 5 with respect to the total mass of the ink.
A range of 15% by mass is preferred.

(4) Polyhydric alcohol Polyhydric alcohols include diols, triols and glycols. Particularly preferred are:
Propylene glycol, 1,5-pentanediol,
1,2,6-hexanetriol and hexylene glycol, at least one of which is used.

In an ink according to another embodiment of the present invention, the colorant-containing resin fine particles and the pigment fine particles described above are those in which the colorant-containing resin fine particles have a cationic hydrophilic group, and However, there may be mentioned an embodiment having a cationic hydrophilic group or an embodiment in which pigment fine particles are dispersed with a dispersant having a cationic hydrophilic group. (5) Colorant-encapsulating resin fine particles having a cationic hydrophilic group (6) (i) a pigment having a cationic hydrophilic group, and
(Ii) Pigment dispersion in which pigment fine particles are dispersed with a dispersant having a cationic hydrophilic group. These constituent materials will be described below in order.

(5) Colorant-Encapsulated Resin Fine Particles Having a Cationic Hydrophilic Group In the ink of this embodiment, colorant-encapsulated resin fine particles having a cationic hydrophilic group are used. First,
As the colorant-encapsulated resin fine particles, for example, a resin in which the colorant is microencapsulated, a dye or pigment dispersed or dissolved in an oily solvent is emulsified and the colorant is encapsulated,
An aqueous dispersion of a resin having a cationic group may be mentioned, but a resin in which a colorant is microencapsulated is particularly preferable. The resin in which the colorant is microencapsulated is obtained by dissolving or dispersing the colorant in an oily solvent, emulsifying and dispersing the same in water, and further performing microencapsulation by a conventionally known appropriate method. It is a resin dispersion. As the coloring agent, those described above in (1) can be used.

Next, a method of preparing a resin in which a colorant is microencapsulated as the colorant-containing resin will be described. First, the colorant is dissolved or dispersed in an oily solvent, and then the oily solvent containing the colorant 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, a method using various dispersers, and a stirrer. At this time, if necessary, various emulsifiers and dispersants, and further, emulsifying or dispersing aids such as protective colloids can be used.
As these emulsifiers or dispersion aids, PVA, PV
In addition to high molecular substances such as P and gum arabic, anionic surfactants, nonionic surfactants and the like can be used.

As a method for microencapsulation of the above-mentioned emulsion, a method of dissolving a colorant and a resin in a water-insoluble organic solvent (oil-based solvent) and then inverting the aqueous phase to emulsify the organic phase, An interfacial polymerization method in which a polymerization reaction is caused at an interface with an aqueous phase to form microcapsules, a material forming a wall only in an organic phase is dissolved or present to form microcapsules, a so-called In-Situ polymerization method,
A coacervation method, in which the concentrated phase of the polymer is phase-separated by changing the pH, temperature, concentration, etc. of the aqueous solution of the polymer to form microcapsules, may be mentioned. After forming the microcapsules, a step of removing the oily solvent is added. The average particle diameter of the colorant-containing resin obtained as described above is 0.01 to 2.0 μm.
m, preferably in the range of 0.05 to 1 μm.

To obtain colorant-containing resin fine particles having a cationic hydrophilic group, a polymer and a salt thereof may be synthesized using a monomer having a cationic group as described below. As the monomer having a cationic group,
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-COO-C 2 H 4} N (CH 3) 2 ], N, N-dimethylaminopropyl methacrylate _{[CH 2 = C (CH 3)} -C
_{OO-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
= CH-CON (CH 3)} 2 ], N, N-dimethyl methacrylamide _{[CH 2 = C (CH 3)} -CON (CH 3) 2 ], N,
N-dimethylaminoethyl acrylamide [CH ₂ ＣC
H-CONHC ₂ H ₄ N (CH ₃ ) ₂ ], N, N-dimethylaminoethyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CO
_{NHC 2 H 4 N (CH 3} ) 2 ], N, = N-dimethylaminopropyl acrylamide _{[CH 2 CH-CONH-C 3} H 6
N (CH _{3) 2],} N, N-dimethylaminopropyl methacrylamide _{[CH 2 = C (CH 3)} -CONH-C 3 H 6 N
(CH ₃ ) ₂ ].

Compounds for forming salts include:
In the case of a tertiary amine, hydrochloric acid, sulfuric acid or acetic acid is used, and as a compound for forming a quaternary amine salt, methyl chloride, dimethyl sulfate, benzyl chloride or epichlorohydrin is used.

(6) (i) a pigment having a cationic hydrophilic group, and (ii) a pigment dispersion in which pigment fine particles are dispersed with a dispersant having a cationic hydrophilic group. (I) having a cationic hydrophilic group. Pigment As the pigment used in the ink of the present invention, conventionally known carbon blacks and organic pigments can be used without any problem. Particularly preferably, at least one kind of cationic hydrophilic group has a direct or other atomic property on the surface of the carbon black. A self-dispersed carbon black bonded through a group is used.
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.

[0044]

However, in the above formula, R represents 1 to 12 carbon atoms.
Represents a linear or branched alkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group.

Incidentally, the cationic hydrophilic group as described above may be directly bonded to the surface of carbon black, or another atomic group may be interposed between the carbon black surface and the hydrophilic group. Alternatively, the hydrophilic group may be indirectly bonded to the carbon black surface. Here, specific examples of the other atomic groups include, for example, those 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. Further, 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 and -Ph-CO
OM and the like (where M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, and Ph represents a phenylene group).

Further, two or more of the above-mentioned self-dispersion type carbon blacks may be appropriately selected and used as a coloring material of an ink. The amount of the self-dispersible carbon black in the ink is preferably 0.1 to 15% by weight, and particularly preferably 1 to 10% by weight based on the total weight of the ink. By setting the content within this range, the self-dispersion type carbon black can maintain a sufficient dispersion state in the ink.

(Ii) Pigment dispersion in which fine pigment particles are dispersed with a dispersant having a cationic hydrophilic group In the aqueous ink composition of the present invention, not only the above-mentioned pigment containing a cationic hydrophilic group but also Alternatively, a pigment dispersion in which a pigment such as the above-described conventionally known carbon black is dispersed with a dispersant containing a cationic group may be used. The pigment dispersant having a cationic hydrophilic group used in this case is illustrated below, but the cationic dispersant that can be used in the present invention is not limited to these.

The cationic dispersant is, for example, one obtained by polymerization of a vinyl monomer, and a cationic polymer dispersant using a cationic monomer as a monomer for constituting at least a part of the obtained polymer. And an amine salt type or quaternary ammonium salt type cationic surfactant.

The cationic monomer used at this time includes, for example, N, N-dimethylaminoethyl methacrylate [CH ₂ ＣC (CH ₃ ) —COO—C ₂ H ₄ N (C
H _{3) 2],} N, N-dimethylaminoethyl acrylate _{[CH 2 = CH-COO-C} 2 H 4 N (CH 3) 2 ], N, N
-Dimethylaminopropyl methacrylate [CH ₂ ＣC
_{(CH 3) -COO-C 3} H 6 N (CH 3) 2 ], N, N-dimethylaminopropyl acrylate [CH ₂ = CH-CO
_{O-C 3 H 6 N (} CH 3) 2 ], N, N-dimethylacrylamide _{[CH 2 = CH-CON (CH} 3) 2 ], N, N-dimethyl methacrylamide [CH ₂ = C (CH ₃₎ −CON (C
H _{3) 2],} N, N-dimethylaminoethyl acrylamide _{[CH 2 = CH-CONHC 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 (} CH 3) 2 ], N, N-dimethylaminopropyl methacrylamide _{[CH 2 = C (CH 3)} -CO
_{NH-C 3 H 6 N (} CH 3) 2 ], and the like.

In the case of the tertiary amine type, examples of the compound for forming a salt include hydrochloric acid, sulfuric acid and acetic acid, and the compounds used for quaternization include methyl chloride, dimethyl sulfate and benzyl. Chloride and epichlorohydrin. Among them, methyl chloride, dimethyl sulfate and the like are preferable in preparing the pigment dispersant used in the present invention. The tertiary amine salt or ammonium compound as described above behaves as a cation in water, and is acidic in a stable dissolution region under neutralized conditions. The content of these monomers in the polymer is 20 to 6
A range of 0% by weight is preferred.

Examples of other monomers used in the constitution of the cationic polymer dispersant include 2-hydroxyethyl methacrylate, acrylic acid having a hydroxy group such as acrylic acid ester having a long ethylene oxide chain in the side chain, and the like. Examples of hydrophobic monomers such as esters and styrene-based monomers and water-soluble monomers that can be dissolved in water having a pH of about 7 include acrylamides, vinyl ethers, vinylpyrrolidones, vinylpyridines, and vinyloxazolines.

As the hydrophobic monomer, for example, hydrophobic monomers such as styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene 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 in order to make the copolymer stably exist in an aqueous solution, and the hydrophobic monomer is used in the copolymer. In order to enhance the dispersing effect on the pigment, it is preferable to use it in the range of 20 to 40% by weight.

When the pigment is dispersed by using such a cationic water-soluble polymer as a dispersant, a pigment whose isoelectric point is adjusted to 6 or more is preferable in terms of physical properties.
Alternatively, a pigment having a neutral or basic pH, for example, a pigment having a neutral pH of 7 to 10, which is characteristic of the pigment, 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 a fine particle aqueous dispersion of a pigment using the above materials, for example, carbon black is subjected to a premixing treatment in a cationic dispersant solution, subsequently milled with a high shear rate dispersion device, and diluted. A centrifugation process 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 aqueous dispersion of the ink thus produced is preferably in the range of 3 to 7.

The physical properties of the aqueous ink composition of the present invention comprising the above constituent materials can be appropriately controlled according to the purpose of use. However, when used for ink jet recording, the viscosity of the ink is 10 cps or less. The surface tension of the ink is preferably 30 to 50 dyne / cm in order to obtain stable ejection.

Next, the ink cartridge, recording unit, ink jet recording apparatus, and ink jet recording apparatus according to the present invention, to which the ink comprising the aqueous ink composition of the present invention having the above-described structure is preferably applied, are preferably used for these apparatuses. A specific example of the configuration of the liquid ejection head to be used will be described. FIG. 1 shows an example of a liquid discharge head as a discharge type ink jet recording head suitable for the ink jet recording apparatus of the present invention, which communicates bubbles with the atmosphere at the time of discharge, and an example of an ink jet printer as a liquid discharge apparatus using this head. It is a schematic perspective view which shows a principal part.

In FIG. 1, the ink jet printer is a conveying device that intermittently conveys a sheet 1028 as a recording material provided in a casing 1008 along a longitudinal direction in a direction indicated by an arrow P in the figure. 1030,
A recording unit 1010 that is reciprocated along a guide shaft 1014 substantially parallel to an arrow S direction that is substantially perpendicular to the conveyance direction P of the paper 1028 by the conveyance device 1030, and a movement as a driving unit that reciprocates the recording unit 1010. And a drive unit 1006.

The movement driving unit 1006 is provided with pulleys 1026a arranged on rotating shafts arranged to face each other at a predetermined interval.
And the belt 10 wound around the pulley 1026b.
16, a roller unit 1022a, and a motor 1018 arranged substantially parallel to the roller unit 1022b and driving a belt 1016 connected to the carriage member 1010a of the recording unit 1010 in the forward and reverse directions. I have.

When the motor 1018 is activated and the belt 1016 rotates in the direction of arrow R in FIG.
The carriage member 1010a of 010 is moved by a predetermined movement amount in the direction of arrow S in FIG. Also, the motor 1018
Is activated and the belt 1016 rotates in the direction opposite to the arrow R direction shown in the figure, the carriage member 1010a of the recording unit 1010 moves by a predetermined amount in the direction opposite to the direction indicated by the arrow S in FIG. It will be moved by an amount. Further, one end of the movement driving unit 1006 is provided with a recording unit 1 at a position which is a home position of the carriage member 1010a.
Recovery unit 102 for performing the discharge recovery process of 010
6 is provided to face the ink ejection orifice arrangement of the recording unit 1010.

The recording unit 1010 includes ink jet cartridges (hereinafter, sometimes simply referred to as cartridges) 1012Y, 1012M, 1012C, and 1012.
B is a carriage member 1010a for each color, for example, yellow, magenta, cyan, and black ink, respectively.
It is provided detachably with respect to.

FIG. 2 shows an example of an ink jet cartridge that can be mounted on the above-described ink jet recording apparatus.
The cartridge 1012 in this example is of a serial type, and its main part is composed of an ink jet recording head 100 and a liquid tank 1001 that stores a liquid such as ink.

The ink jet recording head 100 has a large number of discharge ports 832 for discharging liquid, and a liquid such as ink is supplied from the liquid tank 1001 to a common liquid discharge head 100 via a liquid supply passage (not shown). It is led to a liquid chamber (see FIG. 3). FIG.
In the cartridge 1012 shown in FIG. 1, the ink jet recording head 100 and the liquid tank 1001 are integrally formed so that liquid can be supplied into the liquid tank 1001 as necessary.
Alternatively, a structure in which the liquid tanks 1001 are exchangeably connected to each other may be adopted.

A specific example of the above-described liquid discharge head that can be mounted on the ink jet printer having such a configuration will be described in more detail below. FIG. 3 is a schematic perspective view schematically showing a main part of a liquid ejection head suitable for the ink jet recording apparatus of the present invention. FIGS. 4 to 7 show the shape of the ejection port of the liquid ejection head shown in FIG. FIG. Note that, in these drawings, electrical wiring and the like for driving the electrothermal transducer are omitted.

In the liquid discharge head used in the present invention, for example, a substrate 934 made of glass, ceramics, plastic, metal or the like as shown in FIG. 3 is used. Such a material of the substrate is not the essence of the present invention, and functions as a part of the flow path constituting member, and serves as a support of the ink discharge energy generating element, and a liquid layer to be described later, a material layer forming the discharge port. There is no particular limitation as long as it can function. Therefore, in this example, Si
A case where a substrate (wafer) is used will be described. The ink discharge ports are formed on such a substrate 934. As a method for forming the ink discharge ports, for example, using an orifice plate (discharge port plate) 935 described later as a photosensitive resin in addition to a laser beam forming method, an MPA (Mirror Project) is used.
and an exposure apparatus such as an ion aluminer.

In FIG. 3, reference numeral 934 denotes an electrothermal transducer (hereinafter, sometimes referred to as a heater) 931;
A substrate provided with an ink supply port 933 composed of a long groove-shaped through-hole as a common liquid chamber, and heaters 931 as heat energy generating means are staggered in a row on both sides in the longitudinal direction of the ink supply port 933. The intervals between the electrothermal conversion elements are arranged at, for example, 300 dpi. or,
The substrate 934 is provided with an ink flow path wall 936 for forming an ink flow path. This ink flow path wall 9
The discharge port plate 9 further includes a discharge port 832.
35 are provided.

Here, in FIG.
36 and the discharge port plate 935 are shown as separate members, but the ink flow path wall 936 is formed on the substrate 934 by, for example, a method such as spin coating, so that the ink flow path wall 936 and the discharge port plate 935 are ejected. It is also possible to form the outlet plate 935 and the same member at the same time. Here, the ejection port surface (upper surface) 935a is further subjected to a water-repellent treatment.

The illustrated apparatus uses a serial type head that performs recording while scanning in the direction of arrow S in FIG.
For example, recording is performed at 1,200 dpi. The driving frequency is 10 kHz.
Discharge is performed every 00 μs.

As an example of the actual dimensions of the head, for example, as shown in FIG. 4, a partition wall 936a that fluidly isolates adjacent nozzles has a width W = 14 μm. As shown in FIG. 7, the foaming chamber 1337 formed by the ink flow path wall 936 has N ₁ (width of the foaming chamber) = 33 μm, N ₂
(Length dimension of foaming chamber) = 35 μm. Heater 931
Has a size of 30 μm × 30 μm and a heater resistance of 5 μm.
3Ω and the driving voltage is 10.3V. Further, the height of the ink flow path wall 936 and the partition wall 936a is 12 μm, and the thickness of the ejection port plate is 11 μm.

As shown in FIG. 3, the cross section of the discharge port portion 940 provided on the discharge port plate including the discharge port 832 is cut in a direction intersecting the ink discharge direction (the thickness direction of the orifice plate 935). The shape of the cross section I tried
As shown in FIG. 5, six protruding portions 832a which are substantially star-shaped and have obtuse angles, and six protruding portions which are alternately arranged between these protruding portions 832a and have acute angles are provided. And a section 832b. That is, the bottom 832b as a region locally distant from the center O of the discharge port is its top, and the rising portion 832a as a region locally close to the center O of the discharge port adjacent to this region is its base. Six grooves are formed in the thickness direction (liquid discharging direction) of the orifice plate shown in FIG. 3 (for the position of the groove, see 1141a in FIG. 11).

In the liquid ejection head of the illustrated example,
The discharge port 940 is formed, for example, by forming two equilateral triangles each having a side of 27 μm cut along a direction intersecting the thickness direction.
It is a shape that is combined in a state rotated 0 degrees,
T ₁ shown in FIG. 5 is 8 μm. The angles of the raised portions 832a are all 120 degrees, and the angles of the bent portions 832b are all 60 degrees.

Therefore, the center O of the discharge port and the center
The center of the groove (the top of the groove and the two adjacent
Connect the center (center of gravity) of the figure formed by connecting the base
The center of gravity G of the polygon to be formed matches.
(See FIG. 5). The opening area of the discharge port 832 in this example is 400
μm^TwoAnd the opening area of the groove (the top of the groove and this top
The area of the figure formed by connecting the two bases adjacent to
About 33μm per piece ^TwoIt has become. FIG. 6 is a diagram
5 is a schematic view showing the state of ink adhesion at the ejection port shown in FIG.
It is.

Next, the operation of ejecting liquid by the ink jet recording head having the above-described configuration will be described with reference to FIGS. 8 to 15 are cross-sectional views for explaining the liquid discharge operation of the liquid discharge head shown in FIGS. 3 to 7, and are XX cross-sectional views of the foaming chamber 1337 shown in FIG.
In this cross section, the end of the discharge port 940 in the thickness direction of the orifice plate is the top 1141a of the groove 1141.

FIG. 8 shows a state in which film-like air bubbles have been generated on the heater. FIG. 9 is about 1 μs after FIG. 8, FIG. 10 is about 2 μs after FIG. 8, and FIG. After about 3 μs, FIG.
Is about 4 μs after FIG. 8, and FIG. 13 is about 5 μs after FIG.
FIG. 14 shows about 6 μs after FIG. 8, and FIG.
Each state after s is shown. In the following description, "fall" or "drop" does not mean "fall in the direction of gravity", and does not mean movement in the direction of the electrothermal transducer regardless of the mounting direction of the head. Say.

First, as shown in FIG. 8, when the air bubbles 101 are generated in the liquid flow path 1338 on the heater 931 due to the energization of the heater 931 based on a recording signal or the like, the air bubbles are generated for 2 μs. Then, as shown in FIG. 9 and FIG. The height of the bubble 101 at the maximum volume is higher than the discharge port surface 935a, but at this time, the pressure of the bubble has been reduced from a fraction of the atmospheric pressure to a fraction of the atmospheric pressure.

Next, at about 2 μs after the generation of the bubble 101, the bubble 101 starts to decrease in volume from the maximum volume as described above, and at the same time, the formation of the meniscus 102 also starts. As shown in FIG. 11, the meniscus 102 also retreats toward the heater 931 side, that is, falls.

Here, in the liquid discharge head of the illustrated example, since the plurality of grooves 1141 are provided in the discharge port portion in a dispersed state, when the meniscus 102 retreats, Meniscus retreat direction F
Capillary force acts in the direction FC opposite to M. As a result, even if the slight variation in state of the bubble 101 by some cause was observed, meniscus and the main liquid droplet at the time of retraction of the meniscus (hereinafter, may be described as liquid or ink) the shape of I _a Is corrected so as to be substantially symmetrical with respect to the center of the discharge port.

In the liquid ejection head of the illustrated example, since the falling speed of the meniscus 102 is faster than the contraction speed of the bubble 101, as shown in FIG. 12, at about 4 μs after the bubble generation, as shown in FIG. Bubbles 101 are the discharge ports 83
2 communicates with the atmosphere near the lower surface. At this time, the discharge port 83
The liquid (ink) near the central axis of No. 2 falls toward the heater 931. This negative pressure fluid that is drawn back to the heater 931 side by the (ink) I _a of the bubble 101 before communicating with the atmosphere retains the velocity of the heater 931 side direction by inertia even after the air communication of the bubble 101 Because.

The liquid (ink) which has dropped toward the heater 931 reaches the surface of the heater 931 at about 5 μs after the generation of the bubble 101 as shown in FIG. 13, and as shown in FIG. , So as to cover the surface of the heater 931. The liquid thus spread to cover the surface of the heater 931 has a horizontal vector along the surface of the heater 931, but intersects the surface of the heater 931, for example, the vector in the vertical direction disappears and the heater 931 disappears. Attempts to remain on the surface of 931 and pull the liquid above it, that is, the liquid that maintains the velocity vector in the ejection direction, downward.

[0079] Then, FIG. 15 and the liquid that has spread on the surface of the heater 931, the liquid portion I _b between the upper liquid (main droplet) is Yuki tapered at a later time about 7μs from the generation of the bubble 101 liquid portion I _b is cut in the middle of the surface of the heater 931 as illustrated in, the main liquid droplet I _a keeping a velocity vector in the ejecting direction, a liquid I _c that has spread on the surface of the heater 931
And separated. Thus, the position of separation is the liquid flow path 133.
8, more preferably, on the electrothermal conversion element 931 side than the discharge port 832.

The main droplet _Ia is ejected from the central portion of the ejection port 832 without deviation in the ejection direction and without being distorted, and lands at a predetermined position on the recording surface of the recording material. or,
The liquid I _c spread on the surface of the heater 931 flies as a satellite droplet following the main droplet in the related art, but stays on the surface of the heater 931 and is not discharged.

As described above, since the ejection of the satellite droplets can be suppressed, the splash which is likely to be generated by the ejection of the satellite droplets can be prevented, and the recording surface of the recording material can be prevented by the mist floating in the mist. It is possible to reliably prevent contamination. Note that in FIG. 12-15, ink adhering to the I _d is the groove (ink in the groove),
Also, _Ie represents the ink remaining in the liquid flow path 1338.

As described above, in the liquid ejection head of the illustrated example, when the liquid is ejected in the volume reduction stage after the bubble has grown to the maximum volume, the plurality of grooves dispersed with respect to the center of the ejection port is used. The direction of the main droplet during ejection can be stabilized. As a result, it is possible to provide a liquid ejection head with high landing accuracy, which has no deviation in the ejection direction. In addition, high-speed and high-definition printing can be realized because the ejection can be stably performed even with respect to foaming variation at a high driving frequency.

In particular, in the liquid ejection head of the illustrated example,
In the stage of reducing the volume of bubbles, by discharging the liquid by first communicating the bubbles with the atmosphere, it is possible to prevent mist generated when the bubbles are communicated with the atmosphere and discharge droplets. It is also possible to suppress a state in which droplets adhere to the ejection port surface, which is a cause of ejection. As another embodiment of a recording head of a discharge method that allows bubbles to be communicated with the atmosphere at the time of discharging as described above, which can be suitably used in the present invention, for example, as described in Japanese Patent No. 2783647, a so-called edge shooter type Is mentioned.

The water-soluble ink composition of the present invention has an excellent effect particularly in an ink jet recording head or a recording apparatus in which a flying liquid droplet is formed by using thermal energy to perform recording by using thermal energy. Is to bring. Regarding the typical configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. .

This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, a sheet or liquid path holding a liquid (ink) is used. Generating heat energy in the electrothermal transducer by applying at least one drive signal to the correspondingly arranged electrothermal transducer to provide a rapid temperature rise exceeding film boiling corresponding to the recorded information At the very least, film boiling occurs on the heat-acting surface of the recording head,
As a result, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed, which is effective. Due to the growth and shrinkage of this bubble, the liquid (ink)
To form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

At this time, the pulse-shaped drive signal includes
US Patent Nos. 4,463,359 and 4,3
Those described in US Pat. No. 45,262 are suitable. If the conditions described in U.S. Pat. No. 4,313,124 relating to the invention regarding the rate of temperature rise of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the ink cartridge, the recording unit, and the recording head constituting the ink jet recording apparatus of the present invention include the discharge port, the liquid path, and the electrothermal converter as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,558,333 which disclose a configuration in which a heat acting portion is arranged in a bent region in addition to a combination configuration (a linear liquid flow path or a right-angled liquid flow path). , 45
It is also preferable to use a structure using the specification of Japanese Patent No. 9,600.

In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and absorbs pressure waves of thermal energy. The present invention is also effective as a configuration based on JP-A-59-138461, which discloses a configuration in which an opening corresponds to a discharge unit.

Further, as a full-line type recording head having a length corresponding to the width of the recording material in the maximum range that can be recorded by the recording apparatus, a combination of a plurality of recording heads as disclosed in the above specification is used. , Or a single recording head integrally formed, the above-described effects can be more effectively exhibited by using the aqueous ink composition of the present invention. Can be.

In addition, the print head is replaceable with a print head of a chip type which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

It is preferable to add recovery means for the recording head, preliminary auxiliary means, and the like provided in the ink jet recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, an electrothermal transducer or another heating element other than this, or preheating means by a combination thereof, It is also effective to perform a preliminary ejection mode for performing another ejection in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only a mainstream color such as black, and may be a single-color recording head or a combination of plural recording heads. Alternatively, it is extremely effective to apply the ink comprising the water-based ink composition of the present invention to an apparatus provided with at least one of full colors by color mixture.

In the examples described above, the case where the ink comprising the aqueous ink composition of the present invention is in a liquid state has been described. However, an ink which solidifies at room temperature or lower and which softens at room temperature or Or, in the above-mentioned ink jet system, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Therefore, any ink may be used as long as the ink is in a liquid state when the use recording signal is applied.

In addition, the temperature rise due to thermal energy is positively prevented by using it as energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing the evaporation of the ink. In any case, the ink is liquefied by applying the thermal energy according to the recording signal, and the ink is ejected as a liquid ink, or the ink already starts to solidify when it reaches the recording material. Use of an ink having a property of being liquefied for the first time by thermal energy, such as described above, is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-568.
No. 47 or Japanese Unexamined Patent Publication No. Sho 60-71260, in a state in which the liquid sheet or the solid sheet is held as a liquid or solid substance in the concave portion or through hole of the porous sheet and faces the electrothermal converter. It may be. In the present invention,
The most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention may be an image output terminal of an information processing apparatus such as a word processor or a computer, which may be provided integrally or separately, a copying apparatus combined with a reader,
Further, a facsimile apparatus having a transmission / reception function may be employed.

Next, an outline of a liquid ejection apparatus equipped with the above-described liquid ejection head will be described. FIG. 16 is a schematic perspective view of an ink jet recording apparatus 600 which is an example of a liquid discharge apparatus to which the liquid discharge head having the above-described configuration can be mounted and applied.

Referring to FIG. 16, an ink jet head cartridge 601 has the above-described liquid discharge head and an ink tank for holding ink to be supplied to the liquid discharge head. The inkjet head cartridge 601 is mounted on a carriage 607 that engages with a spiral groove 606 of a lead screw 605 that rotates via driving force transmission gears 603 and 604 in conjunction with forward and reverse rotation of a driving motor 602. The carriage 607 is reciprocated along the guide 608 with the power of the drive motor 602 in the directions of arrows a and b. The recording material P ′ is transported on the platen roller 609 by a recording material transporting means (not shown),
10, the carriage 607 is pressed against the platen roller 609 in the moving direction of the carriage 607.

In the vicinity of one end of the lead screw 605,
Photocouplers 611 and 612 are provided. These are home position detecting means for confirming the presence of the lever 607a of the carriage 607 in this area and switching the rotation direction of the drive motor 602 and the like.

The support member 613 supports the cap member 614 that covers the front surface (discharge port surface) of the above-described ink jet head cartridge 601 having the discharge ports.
Further, the ink suction means 615 is for suctioning the ink accumulated inside the cap member 614 due to idle discharge or the like from the inkjet head cartridge 601. The ink suction unit 615 allows the ink-jet head cartridge 601 to pass through an opening (not shown) in the cap.
Suction recovery is performed. A cleaning blade 617 for wiping the ejection port surface of the ink jet head cartridge 601 is provided so as to be movable in a front-rear direction (a direction perpendicular to the moving direction of the carriage 607) by a moving member 618. These cleaning blades 61
7 and the moving member 618 are supported by the main body support 619. The cleaning blade 617 is not limited to this mode, and may be another known cleaning blade.

In the suction recovery operation of the liquid discharge head, the lever 620 for starting suction moves along with the movement of the cam 621 engaging with the carriage 607.
The movement of the driving force from the driving motor 602 is controlled by known transmission means such as clutch switching. An ink jet recording control unit for giving a signal to a heating element provided in the liquid ejection head of the ink jet head cartridge 601 and for controlling the driving of each mechanism described above is provided on the apparatus main body side. Not shown.

In the ink jet recording apparatus 600 having the above-described configuration, the ink jet head cartridge 601 moves the recording material P ' Recording while reciprocating over the entire width of '.

[0102]

The present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and percentages are by weight unless otherwise specified. <Example 1> (1) Preparation of carbon black-encapsulated anionic resin particles First, the following materials were mixed and dispersed. -Carbon black: MCF-88 (manufactured by Mitsubishi Chemical) 20 parts by weight-Styrene acrylic acid (acid value 200, molecular weight 30,000) 40 parts by weight-Methyl ethyl ketone 40 parts by weight Next, the obtained mixture is mixed with sodium hydroxide Phase inversion emulsification was performed as a neutralizing agent, and methyl ethyl ketone was removed.
An aqueous dispersion of an anionic resin containing 0 micron carbon black was obtained. (2) Pigment fine particles Also, as anionic self-dispersion type carbon black particles, self-dispersion type carbon black CAB manufactured by Cabot Corporation
-O-JET200 (solid content concentration 20 wt%, having a sulfone group as a surface functional group) was prepared. The average particle size of the self-dispersing carbon black particles is 0.13 μm.
m, pH = 7.

(3) Preparation of Ink Composition An ink having the following composition was prepared using each of the materials obtained above. [Ink composition of Example 1]-Carbon black-encapsulated anionic resin particles (using 15 ml of the above aqueous dispersion) 3.0 parts-Anionic self-dispersible carbon black particles 3.0 parts-Propylene urea 7.5 parts- 1,2,6-hexanetriol 1.0 part ・ Ion-exchanged water 85.5 parts

Example 2 (1) Preparation of Cationic Resin Particles Containing Carbon Black First, the following materials were mixed and dispersed. -20 parts by weight of carbon black MCF-88 (manufactured by Mitsubishi Chemical Corporation)-40 parts by weight of styrene-N, N-dimethylaminoethyl methacrylate copolymer (molecular weight 45,000)-40 parts by weight of methyl ethyl ketone The resulting mixture is subjected to phase inversion emulsification using acetic acid as a neutralizing agent to remove methyl ethyl ketone, and finally, an aqueous dispersion of a cationic resin containing 20 wt% of solid content and containing carbon black having an average particle diameter of 0.10 μm. I got

(2) Preparation of Pigment Fine Particles Cationic self-dispersible carbon black particles were prepared as follows. That is, DBP with a surface area of 230 m ² / g
10 g of carbon black with an oil absorption of 70 ml / 100 g
And 3.06 g of 3-amino-N-ethylpyridinium bromide were mixed well with 72 g of water, and 1.62 g of nitric acid was added dropwise thereto, followed by stirring at 70 ° C. After a few more minutes, an aqueous solution in which 1.07 g of sodium nitrite was dissolved in 5 g of water was added, and the mixture was further stirred for 1 hour. The obtained slurry was filtered through filter paper (trade name: Toyo Filter Paper No. 2; manufactured by Advantis), and the pigment particles were sufficiently washed with water.
The pigment was dried in an oven at a temperature of 10 ° C., and water was added to the pigment to prepare an aqueous pigment solution having a pigment concentration of 10% by weight. By the above method, cationic self-dispersible carbon black particles having a cationic group introduced to the surface of carbon black were prepared.

(3) Preparation of Ink Composition An ink having the following composition was prepared using each material prepared above. (Ink composition of Example 2) Carbon black-containing cationic resin particles (15 ml of the aqueous dispersion is used) 2.0 parts Cationic self-dispersible carbon black particles 4.0 parts Propylene urea 7.5 parts Propylene glycol 1.0 part ・ Ion exchange water 85.5 parts

<Example 3> An ink having the following composition was prepared using the same cationic resin particles containing carbon black and cationic self-dispersible carbon black as those prepared in Example 2.

[Ink Composition of Example 3] Cationic resin particles containing carbon black (Example 2)
2.0 parts ・ Cationic self-dispersion type carbon black particles 4.0 parts ・ Glycerin 5.0 parts ・ Ethylene urea 10.0 parts ・ Ion exchanged water 79.0 parts

<Comparative Example 1> An ink having the following composition was prepared using the same carbon black-containing cationic resin particles and cationic self-dispersible carbon black particles as those prepared in Example 2. [Ink Composition of Comparative Example 1] Cationic resin particles containing carbon black (Example 2)
2.0 parts of cationic self-dispersible carbon black particles 4.0 parts Diethylene glycol 5.0 parts Ion-exchanged water 89.0 parts

<Evaluation> (Intermittent Ejection Stability Evaluation Method and Evaluation Criteria) The inks of Examples 1 to 3 and Comparative Example 1 were used to evaluate the intermittent ejection stability of the ink jet head. Evaluation was performed using a BJF-800 manufactured by Canon Inc.
Performed with k heads. First, under an environment of 25 ° C./50 RH%, vertical ruled lines are printed at intervals of a certain discharge pause time.
After a certain pause time, a vertical ruled line formed by first discharging was visually evaluated according to the following criteria. Table 1 shows the results of the evaluation for each pause time.

A: Printing can be performed normally without any disturbance in vertical ruled lines. ：: Some disturbance is observed in the vertical ruled line, but there is no problem in actual use. ×: Non-discharge or disturbance was clearly confirmed in the vertical ruled line, and normal printing was not possible.

[0112]

As is evident from Table 1, the inks of Examples 1 to 3 can normally discharge ink even after a fixed discharge pause, and it can be confirmed that these inks have excellent intermittent discharge stability. Was.

(Method for Evaluating Ink Redissolvability and Evaluation Criteria)
Using the inks of Examples 1 to 3 and Comparative Example 1, the resolubility of the evaporated ink was evaluated. For the evaluation, 5.0 g of each test ink was evaporated at 60 ° C. for 15 hours using a glass petri dish. Next, 2.5 g of each new test ink is added to the thickened ink after the evaporation and left at room temperature for 1 hour. Then, the state of each ink after one hour was visually checked.

[0115]

As is clear from Table 2, no thickener remains in the petri dishes of the inks of Examples 1 to 3, and it was confirmed that these inks were excellent in resolubility of the evaporated ink. did it.

[0117]

As described above, according to the present invention, an image having high image density, excellent scratch resistance, water resistance, and marker resistance is provided, and recording when used in ink jet recording. Excellent intermittent ejection stability from the head.
Provided is an ink capable of preventing occurrence of printing deviation and discharge failure due to adhesion of a thickened material of the ink to a discharge port surface of an inkjet head.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a main part of an example of an ink jet printer on which an ink cartridge containing a water-based ink composition of the present invention can be mounted.

FIG. 2 is a schematic perspective view showing an example of the ink jet cartridge of the present invention.

FIG. 3 is a schematic perspective view schematically showing a main part of an example of a liquid ejection head used in the ink jet cartridge shown in FIG.

FIG. 4 is a conceptual diagram illustrating a part of an example of the liquid ejection head illustrated in FIG. 2;

FIG. 5 is an enlarged view of a discharge port shown in FIG.

FIG. 6 is a schematic diagram showing the state of ink adhesion at the ejection port shown in FIG. 5;

FIG. 7 is a schematic diagram of a main part in FIG. 4;

8 is a schematic cross-sectional view corresponding to the XX perspective cross-sectional shape in FIG. 7 and illustrating the liquid discharge operation of the liquid discharge head with time along with FIGS. 9 to 15;

9 is a schematic cross-sectional view corresponding to the XX perspective cross-sectional shape in FIG. 7 and explaining the liquid discharge operation of the liquid discharge head with time along with FIGS. 8 and 10 to 15;

FIG. 10 corresponds to the cross-sectional shape taken along the line XX in FIG.
FIG. 16 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIG. 9 and FIGS.

FIG. 11 corresponds to FIG.
FIG. 16 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 10 and 12 to 15.

FIG. 12 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 16 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 11 and 13 to 15.

13 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 16 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 12, 14, and 15.

14 corresponds to the perspective cross-sectional shape taken along line XX in FIG.
FIG. 16 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 13 and 15;

FIG. 15 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 15 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time in conjunction with FIG. 14;

FIG. 16 is a schematic perspective view of an ink jet recording apparatus 600 which is an example of a liquid ejection apparatus to which the liquid ejection head of the present invention can be mounted and applied.

[Explanation of symbols]

600: inkjet recording device 601: inkjet head cartridge 602: drive motor 603, 604: drive force transmission gear 605: lead screw 606: spiral groove 607: carriage 607a: lever 608: guide 609: platen roller 610: paper holding plate 611, 612: photo coupler 613: support member 614: cap member 615: ink suction means 616: opening in cap 617: cleaning blade 618: moving member 619: main body support 620: (suction start) lever 621: cam 832: discharge port 832a: Raised portion 832b: Depressed portion 931: Electrothermal conversion element (heater, ink ejection energy generating element) 933: Ink supply port (opening) 934: Substrate 935: Orifice plate (ejection port plate) 935a: Discharge port surface 936: Ink flow path wall 936a: Partition wall 940: Discharge port section 1337: Bubble chamber 1338: Liquid flow path 1141: Groove 1141a: Top 100: Ink jet recording head 101: Bubbles 102: Meniscus 1001: Liquid tank 1006: Move Driving unit 1008: Casing 1010: Recording unit 1010a: Carriage member 1012: Cartridge 1012Y, M, C, B: Inkjet cartridge 1014: Guide shaft 1016: Belt 1018: Motor 1020: Driving unit 1022a, 1022b: Roller unit 1024a, 1024b: Roller unit 1026: recovery unit 1026a, 1026b: pulley 1028: paper 1030: transport device 2701: carbon black 2703: water molecule 2705: counter ion 2707: potassium ions 2709: Sodium ion C: Wet Ink F _M: meniscus backward F _C: opposite meniscus backward direction G: center of gravity I: Ink Ia: main droplet (liquid ink) Ib, Ic: Liquid (ink Id: ink attached to the groove (ink in the groove) Ie: ink remaining in the liquid flow path L: line from liquid chamber (ink supply port) to discharge port N ₁ : width dimension of foaming chamber N ₂ : Length of foaming chamber O: Center of discharge port P ': Recording material P: Transport direction of paper R: Rotation direction of belt S: Direction substantially orthogonal to the transport direction of paper T1: Discharge port dimension w: Width of partition wall

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikifumi Ogasawara 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Noriyasu Asagi 3-30-2 Shimomaruko, Ota-ku, Tokyo (72) Inventor Yutaka Kurabayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] An aqueous ink composition containing resin fine particles containing a colorant, pigment fine particles and a polyhydric alcohol, further comprising a compound represented by the following general formula (I): An aqueous ink composition comprising at least one of the compounds represented by the formula (II): (R _{1 to} R ₅ in the above formula are each independently a hydrogen atom, CH
₃ or C ₂ H ₅ ). 2. The pigment fine particles have a cationic hydrophilic group, or the pigment fine particles are dispersed with a dispersant having a cationic hydrophilic group, and the resin fine particles have a cationic hydrophilic group. The aqueous ink composition according to claim 1, wherein 3. The self-dispersible carbon black, wherein the pigment fine particles have at least one hydrophilic group bonded to the surface thereof directly or via another atomic group.
Or the aqueous ink composition according to 2. 4. The resin fine particles containing the coloring agent has a cationic hydrophilic group on the surface.
The aqueous ink composition according to any one of the above. 5. A compound represented by the general formula (I):
The aqueous ink composition according to any one of claims 1 to 4, wherein the aqueous ink composition contains 5 to 15 wt% based on the total mass of the ink. 6. The polyhydric alcohol is glycerin, propylene glycol, 1,5-pentanediol, 1,
The aqueous solution according to any one of claims 1 to 5, wherein the aqueous solution is at least one selected from the group consisting of 2,6-hexanetriol and hexylene glycol, and contains 0.1 to 10% by weight of the polyhydric alcohol. Ink composition. 7. The aqueous ink composition according to claim 1, wherein the aqueous ink composition is for inkjet recording. 8. An ink cartridge, comprising: an ink containing section for containing the aqueous ink composition according to claim 1. Description: 9. A recording unit, comprising: an ink container for storing the aqueous ink composition according to claim 7; and an ink jet head for discharging ink from the ink container. . 10. The aqueous ink composition according to claim 7,
And an inkjet head for discharging the aqueous ink composition. 11. An ink jet recording method comprising a step of applying the aqueous ink composition according to claim 7 to a recording material by an ink jet method.