JP2001164161A - Ink set, ink jet recording process using the ink set, ink jet recording device, ink cartridge, recording unit and process for relieving bleeding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set for color ink jet recording which satisfies various performances required of a black ink, such as printing quality, image fastness, etc., wherein the black ink does not generate bleeding with other color inks. SOLUTION: In the ink set for ink jet recording containing a black ink and color inks, the black ink has a self-dispersing carbon black with at least one cationic group bound directly or via other atomic groups on its surface as a color material, and the color inks have anionic substances and exert a buffering action against the change in hydrogen ion concentration. An ink cartridge or a recording unit comprises this ink set. In an ink jet recording process or an recording device, this ink cartridge and recording unit are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink set, an ink jet recording method, and a method for recording a color image on a recording medium by using inks of a plurality of colors including black ink and combining these inks. For inkjet equipment, especially for plain paper,
With sufficient image density, clear and high quality images can be obtained,
Furthermore, the present invention relates to a color ink set excellent in water resistance and light resistance of a printed matter, an ink jet recording method using the color ink set, and ink jet devices.

[0002]

2. Description of the Related Art Conventionally, in ink-jet recording, a pigment intended to form a black image excellent in robustness such as print density, print quality, water resistance and light resistance, especially on plain paper. Ink that does not cause bleeding (hereinafter referred to as bleed) at the boundary between an image printed with black ink and an image printed with color ink, and an inkjet recording method using the same And equipment has been reported.

For example, JP-A-3-210373 discloses a black ink having acidic carbon black and an alkali-soluble polymer. Japanese Unexamined Patent Application Publication No.
JP-A-134073 describes an ink for inkjet recording in which a dispersion having excellent storage stability and excellent ejection properties in a bubble jet recording apparatus can be easily obtained.

Japanese Patent Application Laid-Open No. 6-57192 discloses a bleed comprising a black ink having at least one anionic dye and a yellow ink containing at least one cationic dye and a polyvalent precipitant. There is described an ink set for inkjet which can prevent the ink jet. Also, JP-A-7-145336 discloses an anionic ink,
Using a cationic ink, at least one of the inks contains a polymer having the ionic properties of the ink, and in the presence of the polymer, the anionic ink and the cationic ink are brought into contact during multicolor printing. Describes an ink set that can reduce bleed.

Japanese Patent Application Laid-Open No. Hei 7-1837 discloses a colorant composed of a pigment, a black ink composed of a dispersant which is insolubilized under a specific pH environment, and a pH value at which the dispersant is insolubilized.
An ink jet printing method and an ink set that can prevent bleeding using a color ink set as described above are described. Japanese Patent Application Laid-Open No. 10-183046 discloses that bleeding using a black ink using carbon black having a cationic group on its surface as a colorant and a color ink using an anionic dye as a colorant is disclosed. Possible ink jet printing methods and ink sets are described.

[0006]

However, as described in the above-mentioned Japanese Patent Application Laid-Open No. 3-210373,
In the case of an ink using an acidic carbon black and an alkali-soluble polymer, the carbon black is dispersed by the alkali-soluble polymer, but this dispersion has a high viscosity, and there are limitations in securing storage stability. Many. In addition, the ink described in JP-A-3-134073 can easily obtain a dispersion excellent in storage stability and ejection property in a bubble jet recording apparatus, but tends to have insufficient print density.

Further, as described in JP-A-6-57192, the coloring material of the black ink contains at least one anionic dye, and the yellow ink contains at least one cationic dye and a polyvalent precipitant. In the case of an inkjet ink set, although bleed is considerably suppressed, it is difficult to sufficiently satisfy all of the print density, print quality, and image fastness of the black ink, and
A problem arises in the color developability of the yellow ink.

Further, as described in the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-145336, when anionic ink and cationic ink are brought into contact with each other in the presence of a polymer during multicolor printing to reduce bleeding. May adversely affect the reliability of the ink depending on the type of polymer to be contained. In particular, during printing, after the ink is ejected from a certain nozzle, if the ink is not ejected from the nozzle for a certain period of time (for example, about 1 minute), the next first ink is ejected from the nozzle. In such a case, stable ejection may not be performed, and there may be a problem that printing is disturbed. In the present specification, hereinafter,
Such a state is referred to as “poorness in oneness”, and the stability of intermittent ejection is referred to as oneness.

Further, as described in JP-A-7-1837, a black ink composed of a colorant composed of a pigment, a dispersant insolubilized under a specific pH environment, and a pH in which the dispersant is insolubilized. In the case of an ink set using a color ink having, bleed is considerably suppressed,
Since the pH of the color ink needs to be acidic, the selectivity of the dye is narrowed, and it is difficult to achieve compatibility with other performances required for the color ink. Further, there is no description regarding the polarity of the coloring material.

[0010] Further, as described in JP-A-10-183046, a black ink using carbon black having a cationic group on its surface as a colorant, and an anionic dye as a colorant. In the case of an ink set using a color ink, the print density, print quality, image fastness, and the like of the black ink can be satisfied, but the effect of suppressing bleed is insufficient.

Accordingly, an object of the present invention is to satisfy various performances such as print quality and image fastness required for black ink, and to provide an image in a boundary area between a black image and a color image formed on a recording medium. An object of the present invention is to provide an ink set capable of obtaining a reduced image more effectively by bleeding.

Another object of the present invention is to provide an ink jet recording method capable of forming a high quality ink jet recorded image in which bleeding in a boundary region between a black image and a color image is more effectively suppressed. . Another object of the present invention is to provide an ink jet recording apparatus which can be used to form a high quality ink jet recorded image in which bleeding in a boundary region between a black image and a color image is sufficiently suppressed. is there.

Another object of the present invention is to provide a recording unit which can be used in the above-described ink jet recording apparatus. Another object of the present invention is to provide an ink cartridge which can be used for forming a high-quality image with less bleed. It is a further object of the present invention to provide a method for more reliably reducing bleed in a boundary region between a black image and a color image.

[0014]

An ink set according to an embodiment of the present invention which can achieve the above object has at least a black ink and a color ink.
In an ink set for recording a color image on a recording medium using inks of a color or more, at least one kind of cationic group is bonded to a surface as a coloring material directly or via another atomic group. Characterized in that the color ink has an anionic substance and has a buffer action against a change in hydrogen ion concentration.

The ink jet recording method according to one embodiment of the present invention, which can achieve the above object, comprises:
A black ink containing a self-dispersion type carbon black having a cationic group bonded to the surface directly or via another atomic group as a color material is ejected from an orifice according to a recording signal, and the recording is performed. Applying a color ink containing an anionic substance and having a buffering action to a change in hydrogen ion concentration from an orifice according to a recording signal, and applying the color ink to a recording medium. It is characterized by having at least.

Further, in the recording unit according to one embodiment of the present invention which can achieve the above object, a cationic group is bonded to the surface as a coloring material directly or through another atomic group. A black ink containing section containing a black ink containing a self-dispersing carbon black, a color containing a color ink containing an anionic substance and having a buffer action against a change in hydrogen ion concentration It is characterized by comprising at least an ink storage section and a head section for discharging each of the black ink and the color ink.

Further, in the ink cartridge according to one embodiment of the present invention which can achieve the above object, a cationic group is bonded to the surface as a coloring material directly or via another atomic group. A black ink containing section containing black ink containing self-dispersible carbon black, and a color ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration. And a color ink container.

Further, an ink jet recording apparatus according to one embodiment of the present invention which can achieve the above object,
A black ink containing section containing a black ink containing a self-dispersible carbon black having a cationic group bonded to the surface thereof directly or via another atomic group as a coloring material, and an anionic substance And containing a color ink containing color ink having a buffering effect on changes in hydrogen ion concentration, and a head for discharging the black ink and the color ink, respectively, at least It is characterized by having.

Further, the bleed mitigation method according to one embodiment of the present invention, which can achieve the above object, is a method for bleeding in a boundary region between a black image and a color image formed on a recording medium by an ink jet method. A self-dispersible carbon black having at least one kind of cationic group bonded to the surface thereof directly or via another atomic group as a colorant in the formation of the black image. Using a black ink, the formation of the color image has an anionic substance, and,
The present invention is characterized in that a color ink having a buffering action against a change in hydrogen ion concentration is used.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments of the present invention. As described above, in a black ink used for inkjet recording, a pigment ink using a pigment as a coloring material is more advantageous than a dye ink in order to ensure high image density and complete image fastness. However, in order to use a pigment as a coloring material of an ink, a certain dispersant is added to disperse the pigment in a good state. Evils are likely to occur. For example, when a polymer type dispersant is used, there have been problems such as the face surface of the head portion becoming easily wet, clogging, and poor storage stability of the ink. Further, when a surfactant type dispersant is used, there are problems that the image density is low and the face of the head portion is easily wetted.

On the other hand, in the case of the specific carbon black used as a coloring material of the black ink in the present invention, the carbon black itself is so-called self-dispersed even without containing a dispersant. No adverse effect is caused by the inclusion of a dispersant in the varnish. That is,
In the case of a carbon black having a cationic group (particularly, a cationic hydrophilic group) bonded directly or via another atomic group to the surface of the carbon black, the function of the hydrophilic group causes the carbon black itself to be an aqueous solution such as water. Since a stable dispersion state can be maintained in the medium, an ink for inkjet recording can be obtained without particularly requiring a dispersant for dispersing the pigment.

Further, in the ink set of the present invention, as a color ink to be combined with the black ink having the above-described structure, an ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration is employed. As a result, bleeding at the different color boundary between the image printed with black ink and the image printed with color ink is effectively prevented. Here, “having a buffer action against a change in hydrogen ion concentration” means that the ink has a specific region in which the change in hydrogen ion concentration is gentle. Specifically, the difference between the pH value of an ink obtained by adding 1.5 ml of a 1N aqueous sulfuric acid solution to 50 ml of color ink and the pH value of the ink in a state where no aqueous sulfuric acid solution is added is 1.
It means having an area within 0. Hereinafter, satisfying the above condition is referred to as “having a buffer action”.

According to the study of the present inventors, the composition of the color ink is changed to an anionic substance (for example, an anionic dye).
And a pH higher than the pH of the black ink
It was found that the bleeding generated between the black ink and the color ink was effectively suppressed by exhibiting the buffering action in the region.

The reason why the above-described effects can be obtained by the ink set of the present invention having the above configuration is considered as follows. When an image in which a black image and a color image are adjacent to each other is printed, and the black ink and the color ink having the above-described configuration are adjacent to each other on a recording medium, carbon black in the black ink and an anionic substance ( In particular, aggregation occurs with an anionic dye). It is considered that the bleeding is effectively prevented by the state in which the carbon black in the black ink and the dye in the color ink cannot move on the recording medium due to the aggregation.

That is, if the electrical neutralization between the self-dispersible carbon black in the black ink and the dye in the color ink occurs stably on the recording medium, the color constituting each ink is The dispersed state or dissolved state of the material or the like is completely destroyed. If the color materials and the like in the black ink and the color ink cannot be moved, they do not enter the areas printed with the respective inks on the recording medium, and bleeding does not occur.

According to the study of the present inventors, the electrical neutralization between the color materials and the like constituting each of the above-mentioned inks is caused by the pH at the boundary when the black ink and the color ink come into contact with each other.
It was found that the bleeding effect was greatly affected by the pH at the boundary. That is, the above 2
When the pH of each type of ink becomes acidic, electrical neutralization of the coloring materials and the like is not enough to completely destroy the dispersed and dissolved states of the coloring materials and the like of each ink. In some cases, the bleed control effect may not be sufficiently achieved. Therefore, in order to more effectively prevent or reduce bleeding, the above-mentioned 2
A value at which the pH at the boundary when the inks come into contact with each other is sufficient to cause electrical neutralization of the colorants enough to completely destroy the dispersed or dissolved state of the colorants in each ink. It is important to be maintained at

Therefore, in the present invention, the color ink is provided with a buffering action against the change of the hydrogen ion concentration, so that the p ink when two kinds of ink come into contact with each other on the recording medium.
The H value is maintained at a state sufficient to completely destroy the dispersed state or the dissolved state of the coloring material or the like of each ink, thereby preventing bleeding of the printed matter.

As described above, the purpose of the ink set of the present invention is to suppress the bleeding between the black ink and the color ink, and special measures are taken for the bleeding between the color inks of different colors. Absent. However, since color inks are often used in images, graphs, and the like, when preparing color inks, if a conventionally known method is used, such as giving quick permeability to sized paper, etc. It is possible to prevent bleeding between the color inks, and it is possible to prevent the printing quality from being greatly reduced in practical use.

Hereinafter, the ink set of the present invention will be described.
As a coloring material, a black ink having a self-dispersion type carbon black in which at least one kind of cationic group is bonded directly or via another atomic group to the surface of carbon black, an anionic substance, and hydrogen Each of the color inks having a buffer action against the change in ion concentration will be described. First, a specific self-dispersion type carbon black which is a constituent material of the black ink will be described.

(Self-dispersion type carbon black) In the ink set of the present invention, as a coloring material of the black ink, a self-dispersion in which at least one kind of cationic group is bonded directly or via another atomic group to the surface of carbon black. Use dispersed carbon black. By using such a self-dispersion type carbon black as a coloring material, it becomes possible to disperse the carbon black in an aqueous medium of the ink in a stable state without using a dispersant.

In the present invention, the hydrophilic group bonded directly or via another atomic group to the surface of the carbon black includes at least one of a phenyl group, a benzyl group, a phenacyl group and a naphthyl group. Aromatic groups,
Alternatively, it is preferable that the polymer comprises a heterocyclic group such as a pyridyl group and at least one cationic group. More preferably, the cationic group bonded to the surface of carbon black is preferably a quaternary ammonium group. Further, those having a quaternary phosphonium group instead of the quaternary ammonium group are also used.

The cationic group bonded to the surface of carbon black preferably used in the present invention includes:
Specific examples include those having a hydrophilic group having the following structure. However, the present invention is not limited to these. However, in the following formula, R represents 1 to 1 carbon atoms.
2 represents a linear or branched alkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group.

[0033]

Embedded image

The content of the self-dispersible carbon black having the above-mentioned cationic group bonded to the surface thereof in the ink is not particularly limited, but is 0.5 to 15.0% of the total weight of the ink. , And particularly preferably in the range of 1.0 to 10.0%. That is, by setting the content in this range, it is possible to further improve the reliability of the inkjet recording ink, such as the print density and the ejection stability of the ink. In a preferred embodiment, the black ink constituting the color ink jet recording ink set of the present invention further includes a resin containing a colorant.

(Resin Containing a Colorant) When a resin containing a colorant is added to the above-described black ink, the black ink is hardly affected without substantially affecting the ink ejection properties and the quality of the black ink. Can enhance the scratch resistance and marker resistance of the image obtained by the method. Examples of the resin containing a colorant (hereinafter also referred to as a colorant-containing resin) include a resin in which a water-insoluble colorant is encapsulated in a resin microcapsule, and a water-insoluble colorant dissolved or dispersed in an oily solvent. Examples thereof include a resin emulsion dispersed in an aqueous medium, and in particular, a microencapsulated resin containing a coloring agent is preferable.

That is, for example, when a water-insoluble colorant such as an oil-soluble dye or pigment is used as the colorant, the colorant and the hydrophobic portion of the resin interact due to microencapsulation. It is presumed that the hydrophobic part of the resin tends to be difficult to be oriented in an aqueous system because of its easiness.
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 effectively suppressed. ,
It is expected that the ink can contribute to further improvement of the ejection stability of ink over a long period of time.

A resin in which a colorant is microencapsulated is a solution in which a water-insoluble colorant or the like is dissolved or dispersed in an oily solvent, emulsified and dispersed in water, and further microcapsulated by a conventionally known appropriate method. It is a resin dispersion obtained by carrying out the conversion. As a coloring agent that can be used at this time, for example, a water-insoluble coloring agent such as a pigment and an oil-soluble dye is suitably used. That is, the water-insoluble colorant is 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 and a channel method, having a primary particle size of 15 to 40 nm, a specific surface area by a BET method of 50 to 300 m ² / g, and a DBP oil absorption. Volume is 40-150ml / 100g, volatile content is 0.5-10
%, And those having characteristics such as a pH value of 2 to 9 are preferably used. As a commercially available product having such characteristics, for example, 2300, no. 900, MCF88, N
o. 33, no. 40, no. 45, no. 52, MA
7, MA8, No. 2200B (Mitsubishi Chemical)
Raven 1255 (all made in Colombia), REGA
L400R, REGAL330R, REGAL660
R, MOGUL L (all made by Cabot), Colo
r Black FW-1, Color Black
FW18, Color BlackS170, Colo
r Black S150, Prtex 35, Pr
index U (all made by Degussa) and the like.

The following dyes are preferably used as oil-soluble dyes. 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, 86 and the like. C. I. Solvent Red 8, 27, 35, 36, 37, 38, 39,
40, 58, 60, 65, 69, 81, 86, 89, 9
1, 92, 97, 99, 100, 109, 118, 11
9, 122, etc. C. I. Solvent blue 14, 24,
26, 34, 37, 38, 39, 42, 43, 45, 4
8, 52, 53, 55, 59, 67 and the like. C. I. Solvent Black 3, 5, 7, 8, 14, 17, 19, 2
0, 22, 24, 26, 27, 28, 29, 43, 45
etc.

In addition, among various conventionally known water-soluble dyes, those obtained by exchanging their counter ions (usually sodium ions, potassium ions and ammonium ions) with an organic amine or the like can be used.

As the above-mentioned various colorants, for example, in order to adjust or supplement the color tone of the color material used in the above-described black ink, it is preferable to select a colorant having the same color tone as the color material. Thereby, the density of the recorded image can be further improved. Therefore, in the present invention, since carbon black is used as the coloring material of the black ink, it is preferable to use carbon black also as the coloring agent of the resin containing the coloring agent. Further, two or more kinds of coloring materials may be used as the coloring agent included in the resin. In this case, each colorant may be separately included in the resin, or each colorant may be included in the common resin.

Next, a method for preparing a resin in which a colorant is microencapsulated as the colorant-encapsulating resin will be described. First, the colorant is dissolved or dispersed in an oily solvent,
Next, 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, a method using various dispersers, and a stirrer. At this time, if necessary, various emulsifiers and dispersants, as well as emulsifiers or dispersing aids such as protective colloids, can be used. As these emulsifiers or dispersing aids, polymer substances such as PVA, PVP and gum arabic, as well as anionic surfactants and nonionic surfactants 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 so-called In-Situ polymerization method in which a material that forms a wall only in an organic phase is dissolved or present to form microcapsules, an aqueous polymer solution The coacervation method of forming a microcapsule by changing the pH, temperature, concentration, etc. of the polymer to phase-separate the dense phase of the polymer. After forming the microcapsules, a step of removing the oily solvent is added. The average particle diameter of the resin containing the colorant obtained as described above is preferably 0.1 to 1.0.
It is preferably in the range of 01 to 2.0 μm, more preferably 0.05 to 1 μm.

In the present invention, it is preferable that the resin containing the coloring agent obtained as described above has a cationic hydrophilic group on the resin surface. As such a resin, it is preferable to use a copolymer of a hydrophilic monomer and a hydrophobic monomer and a salt thereof. As the hydrophilic monomer used at this time, 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 ＣC (CH ₃ ) —COO—C ₃ H ₆ N (C
H _{3) 2],} N, N-dimethylaminopropyl acrylate _{[CH 2 = CH-COO-C} 3 H 6 N (CH 3) 2 ], N,
N-dimethylacrylamide [CH ₂ ＣＨCH-CON (C
H ₃ ) ₂ ], N, N-dimethylmethacrylamide [CH ₂ ＝
_{C (CH 3) -CON (CH} 3) 2 ], N, N-dimethylaminoethyl acrylamide [CH ₂ = CH-CONHC ₂ H
₄ N (CH ₃ ) ₂ ], N, N-dimethylaminoethyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CONHC ₂ H ₄ N (C
H _{3) 2],} N, N-dimethylaminopropyl acrylamide _{[CH 2 = CH-CONH-C} 3 H 6 N (CH 3) 2 ],
N, N-dimethylaminopropyl methacrylamide [C
_{H 2 = C (CH 3)} -CONH-C 3 H 6 N (CH 3) 2 ], and the like.

The compound for forming a salt includes
In the case of a tertiary amine, hydrochloric acid, sulfuric acid, acetic acid and the like are used, and as compounds used for quaternization, methyl chloride, dimethyl sulfate, benzyl chloride, epichlorohydrin and the like are used.

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 content of the colorant-containing resin in the ink as described above is not particularly limited, but is preferably in the range of 0.5 to 10.0% of the total weight of the ink. It is preferable to set it in the range of 1.0 to 7.0%. That is, by setting the content in this range, it is possible to further improve the reliability of the inkjet recording ink, such as the print density and the ejection stability of the ink.

(Color Dye) The color ink used in the present invention is characterized in that it has an anionic substance and has a buffering action against changes in the hydrogen ion concentration. As the coloring material of the color ink, a known dye or pigment is used, and an anionic dye is particularly preferably used in consideration of the coloring property. As the anionic dye, most of the existing dyes can be used as long as they have an appropriate color tone and density, even if they are newly synthesized, or any of these can be mixed. It is also possible to use.

Hereinafter, specific examples of the anionic dye which can be used in the present invention will be illustrated for each color tone of the ink. (Coloring material for yellow) C.I. I. Direct Yellow: 8, 11, 12, 27,
28, 33, 39, 44, 50, 58, 85, 86, 8
7, 88, 89, 98, 100, 110 and 132 C.I. I. Acid Yellow: 1, 3, 7, 11, 17,
23, 25, 29, 36, 38, 40, 42, 44, 7
6, 98 and 99 C.I. I. Reactive Yellow: 2, 3, 17, 2
5, 37 and 42 C.I. I. Food yellow: 3

(Coloring material for magenta) I. Direct Red: 2, 4, 9, 11, 20,
23, 24, 31, 39, 46, 62, 75, 79, 8
0, 83, 89, 95, 197, 201, 218, 22
0, 224, 225, 226, 227, 228, 229
And 230 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, 1
5, 17, 20, 23, 24, 31, 42, 45, 46
And 59 C.I. I. Food Red: 87, 92 and 94

(Coloring Material for Cyan) I. Direct Blue: 1, 15, 22, 25, 4
1, 76, 77, 80, 86, 90, 98, 106, 1
08, 120, 158, 163, 168, 199 and 2
26 C.I. I. Acid Blue: 1, 7, 9, 15, 22, 2
3, 25, 29, 40, 43, 59, 62, 74, 7
8, 80, 90, 100, 102, 104, 117, 1
27, 138, 158 and 161 C.I. I. Reactive Blue: 4, 5, 7, 13, 1
4, 15, 18, 19, 21, 26, 27, 29, 3,
2, 38, 40, 44 and 100

The content of the coloring material is preferably in the range of 0.2 to 15% by weight, more preferably in the range of 0.5 to 10% by weight based on the total weight of the ink.
That is, by setting the content in this range, for example, the reliability as an inkjet recording ink, such as the coloring property and the ejection stability of the ink, can be further improved.

Examples of the aqueous medium used for the color ink include, for example, water or a mixed solvent of water and a water-soluble organic solvent. As the water-soluble organic solvent, it is particularly preferable to use one having an ink drying prevention effect.

Examples of the water-soluble organic solvent that can be used at this time include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol. Alkyl alcohols having 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethylene glycol and polypropylene glycol Polyalkylene glycols; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as ethylene glycol and diethylene glycol; lower alkyl ether acetates such as polyethylene glycol monomethyl ether acetate; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ) Lower alkyl ethers of polyhydric alcohols such as ether and triethylene glycol monomethyl (or ethyl) ether; polyhydric alcohols such as trimethylolpropane and trimethylolethane; N-methyl-2-pyrrolidone, 2-pyrrolidone, 3-dimethyl-2-imidazolidinone and the like.

The water-soluble organic solvent as described above may be used alone or
Alternatively, they can be appropriately selected and used as a mixture. The content of the water-soluble organic solvent in the ink is not particularly limited, but based on the total weight of the ink,
A range of 3 to 50% by weight is preferred. The content of water contained in the ink is 50 to 95% based on the total weight of the ink.
It is preferably in the range of% by weight.

The color inks described above can be used for writing implement inks and ink jet recording inks.
Ink jet recording methods include a recording method in which mechanical energy is applied to ink to eject droplets, and a recording method in which thermal energy is applied to ink to eject droplets by firing the ink. It is particularly suitable for By the way, when the color ink is used for inkjet recording, it is preferable that the ink has an ejection characteristic that allows ejection from an inkjet recording head. From the viewpoint of dischargeability from the inkjet head, the properties of the liquid include, for example, a viscosity of 1 to 15
cps, surface tension is 25 mN / m (dyn / cm) or more, especially viscosity is 1 to 5 cps, and surface tension is 25 to 50.
It is preferably set to mN / m (dyn / cm).

The preferred aqueous medium composition for causing the color ink used in the present invention to have the above-described ejection characteristics includes, for example, glycerin, trimethylolpropane, thioglycol, ethylene glycol, diethylene glycol, isopropyl alcohol and isopropyl alcohol. It is preferable to include acetylene alcohol. still,
Examples of the acetylene alcohol include an acetylene alcohol represented by the following formula.

[0058]

Embedded image In the above formula, R1, R2, R3 and R4 are an alkyl group,
Specifically, for example, it represents a linear or branched alkyl group having 1 to 4 carbon atoms, m and n each represent an integer, and m
= 0 and n = 0, or 1 ≦ m + n ≦ 30,
When m + n = 1, m or n is 0.

Further, the color ink used in the present invention has a buffering effect on the hydrogen ion concentration, and the pH value when 1.5 ml of 1N sulfuric acid aqueous solution is added to 50 ml of color ink, and the pH value before addition. In order to make the difference between the pH values within 1.0, the following method similar to that for preparing a conventionally known buffer solution can be used. Specifically, an ammonium salt of an organic or inorganic acid, an amine salt of an organic or inorganic acid, a hydroxide of an alkali metal, ammonia, a basic amine, a basic amino acid, sodium dihydrogen phosphate are contained in a color ink. , Glycine, sodium chloride, sodium tetraborate, sodium carbonate, sodium bicarbonate, hydrochloric acid, sodium carbonate, dimethylglycine sodium, boric acid, alkali metal chlorides, buffering agents such as polyamine and polyimine alone, Alternatively, they can be used in appropriate combination. Specific examples of the combination include, for example, sodium dihydrogen phosphate / sodium hydroxide, glycine + sodium chloride /
Sodium hydroxide, sodium tetraborate / sodium hydroxide, sodium dihydrogen phosphate / sodium tetraborate,
Sodium tetraborate / sodium carbonate, hydrochloric acid / sodium carbonate, sodium dihydrogen phosphate / sodium hydroxide,
Buffers such as ammonium chloride / ammonia, sodium dimethylglycine / hydrochloric acid, boric acid + potassium chloride / sodium carbonate, sodium carbonate / sodium bicarbonate, and the like.

In the present invention, any of the above-mentioned ones can be preferably used. However, since it has been found that bleeding can be effectively prevented by giving the color ink a stronger buffering action, the organic acid or It is preferable to include at least one member selected from the group consisting of ammonium salts or amine salts of inorganic acids and at least one member selected from the group consisting of hydroxides of alkali metals, ammonia, basic amines, and basic amino acids.

The content of the compound as described above is
1.5N aqueous sulfuric acid solution in 1.5 ml of 50 ml of color ink
It is preferable to appropriately adjust the color ink so as to satisfy the condition that the difference between the pH value when adding ml and the pH value before addition is within 1.0. However, at this time, it is necessary to set the color developing property and the ejection stability of the ink within a range that does not impair the reliability as the ink for inkjet recording.

It is preferable that the color ink contains at least one surfactant having the same polarity as the coloring material in the ink or a nonionic surfactant, in addition to the components described above. By including these surfactants, it is possible to impart desired permeability and viscosity to the ink,
The performance required for the inkjet recording ink can be further satisfied. The surfactant used in this case may be any of the following ionic surfactants, nonionic surfactants and amphoteric surfactants, or a mixture of two or more of them.

(Anionic surfactant) Fatty acid salt, higher alcohol acid ester salt, alkylbenzene sulfonate, higher alcohol phosphate ester salt, alkyl sulfate, alkyl sulfate ester salt, dialkyl sulfosuccinate, alkyl sulfo acetate, and Dialkyl sulfosuccinates and the like.

(Cationic surfactant) Aliphatic amine salt, quaternary ammonium salt, alkylpyridinium salt and the like.

(Nonionic surfactant) Higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, aliphatic ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, aliphatic amide ethylene oxide adduct, higher alcohol Alkylamine ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, fatty acid esters of polyhydric alcohols and fatty acid amides of alkanolamines.

(Amphoteric Surfactants) Amino acid type and betaine type amphoteric surfactants and the like.

In the present invention, all of these are preferably used, and more preferably, ethylene oxide adduct of higher alcohol, ethylene oxide adduct of alkylphenol, ethylene oxide-propylene oxide copolymer, acetylene glycol Non-ionic surfactants such as ethylene oxide adducts are used. Further, those having an addition mole number of the ethylene oxide adduct in the range of 4 to 20 are particularly preferable.

The amount of the above surfactant added to each ink is not particularly limited, but is preferably in the range of 0.01 to 10% by weight based on the total weight of the ink.
If the amount is less than 0.01% by weight, depending on the type of surfactant, desired permeability cannot be generally obtained. If the amount exceeds 10% by weight, the initial viscosity of the ink increases, which is not preferable. More preferably, 0.1 to 5.0 of the total weight of the ink.
It is good to be in the range of weight%.

In addition, in addition to the above components, urea, thiourea, ethylene urea, alkyl urea, and the like as humectants may be contained in each ink constituting the ink set of the present invention.
Nitrogen-containing compounds such as alkyl thiourea, dialkyl urea and dialkyl thiourea, and pH adjusters, viscosity adjusters, preservatives, antioxidants, evaporation promoters, rust inhibitors, Additives such as a mold agent and a chelating agent may be blended.

The ink set of the present invention, which is a combination of the black ink and the color ink described above, is suitably used in an ink jet recording method in which ink droplets are ejected from an orifice according to a recording signal to perform recording on a recording medium. However, it is particularly suitably used for an ink jet recording system in which recording is performed by ejecting ink droplets by the action of thermal energy. As a recording method for suitably performing recording using the ink set of the present invention, an ink jet recording method in which thermal energy corresponding to a recording signal is applied to inks of respective colors accommodated in a recording head and droplets are generated by the energy. In the following, an example of the inkjet recording apparatus of the present invention to which such an inkjet recording method is applied will be described.

First, FIGS. 1, 2 and 3 show examples of the configuration of a head which is a main part of the apparatus. FIG. 1 is a cross-sectional view of the head 13 along the ink flow path, and FIG.
It is sectional drawing in the -B line. The head 13 includes a glass, ceramic or plastic plate or the like having a groove 14 through which ink passes, and a heating head 15 (a thin film head is shown in the figure, but is not limited to this). ) Are adhered. The heating head 15
It comprises a protective film 16 made of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 made of nichrome or the like, a heat storage layer 19, and a substrate 20 having good heat dissipation such as alumina. I have.

The ink 21 has a discharge orifice (fine hole).
22 and a meniscus 23 is formed by the pressure P. Now, aluminum electrodes 17-1 and 17-2
When electric signal information is added to the area, the area indicated by n of the heating head 15 rapidly generates heat, and the ink 21 in contact with the area is heated.
Bubbles are generated, and the meniscus 23 projects by the pressure,
The ink 21 is ejected to form ink droplets 24 and flies from the ejection orifice 22 toward the recording medium 25.

FIG. 3 is an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely contacting a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described with reference to FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating the above head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end, and forms a cantilever. The blade 61 is arranged at a position adjacent to a recording area of the recording head 65, and in the present example, is held in a form protruding into the movement path of the recording head 65. Reference numeral 62 denotes a cap on the ejection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, contacts the ink ejection port surface, and performs capping. Is provided. Further, 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 section 64, and the blade 61 and the ink absorber 63 remove water, dust, and the like from the ink ejection port surface. 65 is a recording head that has ejection energy generating means, and performs recording by ejecting ink to a recording medium facing an ejection port surface where ejection ports are arranged;
Reference numeral 66 denotes a carriage on which the recording head 65 is mounted and moved. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is a motor 68.
(Not shown) connected to the belt 69 driven by the motor. 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 such a configuration, the recording medium is fed to a position facing the discharge port surface of the recording head 65, 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. As a result, the ejection port surface of the recording head 65 is wiped.
When capping is performed with the cap 62 in contact with the ejection surface of the recording head 65, the cap 62 moves so as to protrude into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same positions as the positions 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 movement of the print head 65 to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at the home position adjacent to the printing area at a predetermined interval while the printing head 65 moves through the printing area for printing. And the wiping is performed with this movement.

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

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

As the material of the ink absorber, it is preferable to use polyurethane, cellulose, polyvinyl acetate or polyolefin resin. 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.

FIG. 7 is a perspective view showing an ink jet recording apparatus applicable to the present invention. The recording medium 106 inserted at the sheet feeding position of the recording apparatus is transported by the feed roller 109 to a recordable area of the recording head unit 103. A platen 108 is provided below the recording medium in the recordable area. The carriage 111 is configured to be movable in a direction determined by two guide shafts, a guide shaft 104 and a guide shaft 105, and reciprocally scans a recording area. A carriage 111 includes a print head that discharges a plurality of color inks, and a print head unit 103 that includes an ink tank that supplies ink to each print head.
Is installed. The plurality of color inks provided in the ink jet recording apparatus of this example are four color inks of black (Bk), cyan (C), magenta (M), and yellow (Y).

At the left end of the area where the carriage can move,
A recovery system unit 110 is provided at a lower portion, and the ejection port of the recording head is capped during non-printing. This left end is called the home position of the recording head. Reference numeral 107 denotes a switch unit and a display element unit. The switch unit is used when turning on / off the power of the recording apparatus, setting various recording modes, and the like.

FIG. 8 is a perspective view showing the recording head unit of FIG. Bk, C, M,
A recording head 102 for ejecting ink of each color of Y;
Ink tank 20Bk for C, ink tank 20C for C, M
The ink tank 20M for Y and the ink tank 20Y for Y are mounted. Each tank is connected to the print head via a connection to the print head, and supplies ink to the ejection openings. In addition to this example, for example, the tanks for the respective color inks of C, M, and Y may have an integral structure.

FIG. 9 is an enlarged sectional view of the vicinity of the heating element of the recording head. In the ink jet recording apparatus of this example, a heating element, which is an electric-to-heat converter, is arranged corresponding to each ink ejection port, and a drive signal corresponding to recording information is applied to the heating element to eject ink from a nozzle. The recording method is adopted. The heating element 31 is configured to be capable of independently generating heat for all nozzles.

The ink in the nozzle, which has been rapidly heated by the heat generated by the heating element 31, forms bubbles due to film boiling, and the pressure of the bubble generation causes the ink droplets 35 as shown in FIG.
Is ejected toward the recording medium 106 to form characters and images on the recording medium. Each of the ejection ports 37 is provided with an ink liquid path communicating with the ejection port.
A common liquid chamber 32 for supplying ink to these liquid passages is provided behind the portion where the 8 is provided. In the ink liquid passage corresponding to each of the discharge ports, a heating element 31 which is an electric-to-heat converter that generates thermal energy used for discharging ink droplets from these discharge ports, and supplies power to the heat element 31 Electrode wiring is provided. These heating elements 31 and electrode wirings are formed by a film forming technique on a substrate 33 made of silicon or the like. On the heating element 31,
A protective film 36 is formed so that the ink and the heating element do not come into direct contact with each other. Furthermore, the above-described ejection port, ink liquid path, common liquid chamber, and the like are formed by laminating a partition wall 34 made of resin or glass material on this substrate.

As described above, the recording method using the heating element, which is an electric / heat conversion element, is generally called a bubble jet recording method because it uses bubbles formed by applying thermal energy when ejecting ink droplets. ing. In the above-described recording apparatus of the present invention, an ink-jet recording apparatus that ejects ink droplets by applying thermal energy to ink has been described as an example. May be used as the ink jet recording apparatus.

Next, another specific example of a recording apparatus and a recording head which can be suitably used in the present invention will be described. FIG.
FIG. 1 is a schematic perspective view illustrating a main part of an example of a liquid discharge head as a liquid discharge head of a discharge method according to the present invention in which bubbles communicate with the atmosphere at the time of discharge and an ink jet printer as a liquid discharge device using the head.

In FIG. 10, the ink jet printer uses a sheet P 1028 as a recording medium provided in a casing 1008 along the longitudinal direction as indicated by an arrow P in the drawing.
And a recording unit 1010 that is reciprocated substantially in parallel with a guide shaft 1014 in an arrow S direction substantially perpendicular to the transport direction P of the sheet 1028 by the transport device 1030. , Recording unit 10
Moving drive unit 10 as a driving means for reciprocating the motor 10
06 is included.

The movement driving unit 1006 is provided with pulleys 1026a arranged on rotating shafts arranged to face each other at a predetermined interval.
And a belt 101 wound around a pulley 1026b.
6, a roller unit 1022a, and a motor 1018 that is disposed substantially parallel to the roller unit 1022b and drives a belt 1016 connected to the carriage member 1010a of the recording unit 1010 in the forward and reverse directions.

When the motor 1018 is activated and the belt 1016 rotates in the direction of arrow R in FIG. 10, the carriage member 1010a of the recording unit 1010 moves to the position indicated by arrow S in FIG.
In the direction by a predetermined amount of movement. Also, the motor 101
8, when the belt 1016 rotates in the direction opposite to the direction of the arrow R 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 of 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 port arrangement of the recording unit 1010.

The recording unit 1010 includes ink jet cartridges 1012Y, 1012M, 1012C and 101
2B is detachably provided for the carriage member 1010a for each color, for example, yellow, magenta, cyan, and black.

FIG. 11 shows an example of an ink jet cartridge mountable 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 ejection ports 832 for ejecting liquid.
Liquid such as ink is led from the liquid tank 1001 to a common liquid chamber (see FIG. 12) of the liquid ejection head 100 via a liquid supply passage (not shown). 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. 12 is a schematic perspective view schematically showing a main part of a liquid discharge head suitable for the ink jet recording apparatus of the present invention. FIGS. 13 to 16 show discharge ports of the liquid discharge head shown in FIG. It is a front view which shows a shape. Note that, in these drawings, electrical wiring and the like for driving the electrothermal transducer are omitted.

In the liquid discharge head of this embodiment, a substrate 934 made of glass, ceramics, plastic, metal or the like is used as shown in FIG. 12, for example. The material of such a substrate is not the essence of the present invention,
There is no particular limitation as long as it functions as a part of the flow path constituent member and can function as a support for a material layer forming the ink discharge energy generating element and a liquid flow path and a discharge port described later. . Therefore, in this example, a case where a Si substrate (wafer) is used will be described. Such a substrate 934
An ink discharge port is formed on the upper surface. In addition to the formation method using a laser beam, for example, an orifice plate (discharge port plate) 935 described later is used as a photosensitive resin, and an MPA (Mirror Projection A) is used.
and a method of forming the discharge port by an exposure apparatus such as a liner.

In FIG. 12, reference numeral 934 denotes a substrate provided with an electrothermal conversion element (hereinafter, sometimes referred to as a heater) 931 and an ink supply port 933 comprising a long groove-shaped through hole as a common liquid chamber. On both sides of the opening 933 in the longitudinal direction, heaters 9 serving as thermal energy generating means are provided.
31 are arranged in a zigzag pattern in a row, and the intervals between the electrothermal conversion elements are arranged, for example, at 300 dpi. An ink flow path wall 936 for forming an ink flow path is provided on the substrate 934. 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 and the discharge port plate 935 are formed on the substrate 934 by a method such as spin coating. Can be formed simultaneously as the same member. here,
Further, the ejection port surface (upper surface) 935a is subjected to a water-repellent treatment.

In the illustrated apparatus, recording is performed at, for example, 1,200 dpi using a serial type head that performs recording while scanning in the direction of arrow S in FIG. The driving frequency is 10 kHz, and one ejection port performs ejection at a minimum time interval of 100 μs.

As an example of the actual dimensions of the head, for example, as shown in FIG. 13, a partition wall 936a that fluidly isolates adjacent nozzles has a width w = 14 μm. FIG.
As shown in FIG. 6, the foaming chamber 1337 formed by the ink flow path wall 936 has N ₁ (width of the foaming chamber) = 33 μm.
m, N ₂ (length of foaming chamber) = 35 μm. The size of the heater 931 is 30 μm × 30 μm, the heater resistance value is 53Ω, and the driving voltage is 10.3V. The height of the ink flow path wall 936 and the partition wall 936a is 12 μm.
The thickness of the discharge port plate can be 11 μm.

As shown in FIG. 12, of the cross section of the discharge port portion 940 provided on the discharge port plate including the discharge port 832, cutting is performed in a direction intersecting the ink discharge direction (the thickness direction of the orifice plate 935). As shown in FIG. 14, the shape of the cross section thus obtained is substantially star-shaped, and includes six raised portions 832a having obtuse angles and these raised portions 83.
2a, and is roughly constituted by six ridges 832b alternately arranged and having acute angles. That is, the recess 832 as a region locally separated from the center O of the discharge port
b as its top and a base 832a as a region locally close to the center O of the discharge port adjacent to this region, and six grooves in the thickness direction (liquid discharge direction) of the orifice plate shown in FIG. (Refer to 1141a in FIG. 17 for the position of the groove).

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 thereof into 60 μm.
It has a shape that is combined in a state rotated by degrees, and T1 shown in FIG. 14 is 8 μm. The angles of the raised portions 832a are all 120 degrees, and the angles of the bent portions 832b are all 6 degrees.
0 degrees.

Accordingly, it is formed by connecting the center O of the discharge port and the center of the groove adjacent to each other (the center (center of gravity) of the figure formed by connecting the top of the groove and the two bases adjacent to the top). And the center of gravity G of the polygon. (See FIG. 14) The opening area of the discharge port 832 in this example is 4
A 00Myuemu ^2, the opening area of the groove (and the top of the groove, the area of a figure formed by connecting the two bases adjacent to this top) is about 33 .mu.m ² per. FIG. 15 is a schematic diagram showing the state of ink adhesion at the ejection port shown in FIG.

Next, the operation of discharging the liquid by the ink jet recording head having the above-described configuration will be described with reference to FIGS. 17 to 24 are cross-sectional views for explaining the liquid discharging operation of the liquid discharging head shown in FIGS. 12 to 16, 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 114 of the groove 1141.
1a.

FIG. 17 shows a state in which film-like air bubbles have been generated on the heater. FIG. 18 is about 1 μs after FIG. 17, FIG. 19 is about 2 μs after FIG. 17, FIG. 20 is about 3 μs after FIG. FIG.
1 is about 4 μs after FIG. 17, and FIG. 22 is about 5 μs from FIG.
FIG. 23 shows the state after about 6 μs in FIG. 17, and FIG. 24 shows the state after about 7 μs in FIG. In the following description, "fall" or "drop", "drop"
Does not mean falling in the direction of gravity,
It refers to movement in the direction of the electrothermal conversion element regardless of the mounting direction of the head.

First, as shown in FIG. 17, when air bubbles 101 are generated in the liquid flow path 1338 on the heater 931 due to energization to the heater 931 based on a recording signal or the like, the air bubbles are generated in about 2 μs. As shown in FIGS. 18 and 19, the volume grows rapidly. 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 almost at the same time, the formation of the meniscus 1004 starts. The meniscus 1004 also retreats toward the heater 931 as shown in FIG. 19, 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 1004 retreats, the meniscus Reverse direction F
Capillary force acts in the direction FC opposite to M. As a result, even if a slight variation in the state of the bubble 101 is recognized for some reason, the shape of the meniscus and the main droplet (hereinafter, sometimes referred to as liquid or ink) Ia when the meniscus retreats is The correction is made 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 1004 is faster than the contraction speed of the bubble 101, as shown in FIG. The bubble 101 is the discharge port 8
32 communicates with the atmosphere near the lower surface. At this time, the discharge port 8
The liquid (ink) near the central axis of 32 drops 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. 22, and as shown in FIG. It spreads so as to cover the surface of the heater 931. The liquid spread so as to cover the surface of the heater 931 has a horizontal vector along the surface of the heater 931, but intersects with the surface of the heater 931, for example, the vector in the vertical direction disappears, and the heater 9.
The liquid above it, trying to stay on the surface of 31,
That is, the liquid maintaining the velocity vector in the ejection direction is pulled downward.

[0111] Then, Yuki become liquid portion I _b is thin between the liquid and the upper liquid spread on the surface of the heater 931 (main droplet) in FIG. 24 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 shown, is separated into a liquid I _c that has spread on the surface of the main liquid droplet I _a heater 931 to keep the velocity vector in the discharge direction. Thus, the separation position is desirably inside the liquid flow path 1338, 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 medium. 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, the ejection of the satellite droplets can be suppressed, so that the splash which is easily generated by the ejection of the satellite droplets can be prevented, and the recording surface of the recording medium becomes dirty by the mist floating in the mist. Can be reliably prevented. Incidentally, in FIGS.
_Id is the ink attached to the groove (ink in the groove),
_Ie represents the ink remaining in the liquid flow path.

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,
By discharging the liquid by starting this bubble and communicating with the atmosphere at the stage of reducing the volume of the bubble, it is possible to prevent mist generated when the bubble is connected to the atmosphere and discharge the droplet, so-called sudden non-discharge It is also possible to suppress the state in which droplets adhere to the ejection port surface, which causes the above.

As another embodiment of a recording head of a discharge system which can be suitably used in the present invention and which communicates bubbles with the atmosphere at the time of discharge, as described in Japanese Patent No. 2783647, for example, a so-called edge shooter is disclosed. Type.

The present invention provides an excellent effect particularly in an ink jet recording head or a recording apparatus which performs recording by forming flying droplets by utilizing thermal energy among ink jet recording methods.

The typical structure and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,723,129.
It is preferable to use the basic principle disclosed in the specification of US Pat. No. 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, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and providing a rapid temperature rise exceeding film boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because a film in the liquid (ink) corresponding to this drive signal can be formed one-to-one by causing film boiling on the heat acting surface.
The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble 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.

The driving signal in the form of a pulse is disclosed in US Pat. Nos. 4,463,359 and 4,34,359.
Suitable are those described in US Pat. No. 5,262. If the conditions described in U.S. Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface described above 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 includes 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. 4,459,600, which disclose configurations 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). It is also preferable to use the one having the configuration used.

In addition, JP-A-59-123670, which discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, or absorbs a pressure wave 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 medium in the maximum range in which the recording apparatus can record, a combination of a plurality of recording heads disclosed in the above-mentioned specification is used. However, the present invention can more effectively exhibit the above-described effects, although the configuration may satisfy the length of the recording head or the configuration as a single recording head.

In addition, by being mounted on the apparatus main body, it is possible to make an electrical connection with the apparatus main body and supply ink from the apparatus main body, and to be a replaceable chip type recording head, or to be integrated with the recording 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 structure of the ink jet recording apparatus of the present invention since the effects of the present invention can be further stabilized. is there. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal converter or another heating element or a combination thereof, and printing Performing a preliminary ejection mode for performing another ejection is also effective for performing stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and may be a single recording head or a combination of plural recording heads. The present invention is also very effective for an apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above,
Although the ink is described as a liquid, it is an ink that solidifies at or below room temperature and softens at room temperature or is a liquid, or in the above-described inkjet method, the ink itself is heated to 30 ° C. to 70 ° C. Since it is common to control the temperature so that the viscosity of the ink is in the stable ejection range by adjusting the temperature within the following range, any ink can be used as long as the ink is in a liquid state when the use recording signal is applied. good.

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 to prevent evaporation of the ink. Either ink may be used, or in any case, the ink may be liquefied by application of heat energy according to the recording signal and ejected as a liquid ink, or may already start to solidify when reaching the recording medium. The use of ink having a property of being liquefied for the first time by heat energy is also applicable to the present invention. In such a case, ink is disclosed in JP-A-54-56847.
JP-A No. 60-71260 or JP-A-60-71260, in a state in which the porous sheet is held as a liquid or solid material in a concave portion or a through-hole and faces the electrothermal converter. Is also good. 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 is not limited to the one provided integrally or separately as an image output terminal of an information processing apparatus such as a word processor and a computer, and the other is 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. 25 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.

In FIG. 25, an ink jet head cartridge 601 is formed by integrating 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 medium P ′ is conveyed over the platen roller 609 by a recording medium conveying unit (not shown), and is pressed against the platen roller 609 by the paper pressing plate 610 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 (ejection surface) of the above-described inkjet head cartridge 601 having the ejection openings.
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 engaged 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 configuration, the recording medium P 'conveyed on the platen roller 609 by the recording medium conveying means (not shown) is used to move the ink jet head cartridge 601 to the full width of the recording medium P'. Recording while reciprocating over

[0135]

Next, 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.

First, a cationic self-dispersion type carbon black for use as a coloring material of a black ink was prepared as follows. Of water (carbon black ^{_{1) 30g H 3 N + C}} 6 H 4 N
_{^{+ (CH 3) 3 Cl -}} · I - is in a solution dissolved 3.08 g, is added with stirring silver nitrate 1.69 g. The generated precipitate is removed by filtration, and the filtrate is added to 70 g of water while stirring, to a suspension in which 10 g of carbon black having a specific surface area of 230 m ² / g and DBPA of 70 ml / 100 g is dispersed. Next, 2.25 g of concentrated hydrochloric acid was added, and then a solution of 0.83 g of sodium nitrite dissolved in 10 g of water was added. NN ⁺ C ₆ H ₄ N ⁺ (C
When the diazonium salt having _three H ₃ ) groups reacted with the carbon black and the nitrogen gas bubbles generated with the reaction stopped, the dispersion was dried in an oven at 120 ° C.
As a result, C ₆ H ₄ N ⁺ (CH ₃ )
A product with _three groups was obtained.

[0137]

Embedded image

(Carbon Black 2) 2.12 g of 4-
A solution of acetaminophenacyl chloride, 0.83 g of pyridine, 6.4 g of dimethyl sulfoxide is stirred overnight. After addition of an additional 0.8 g of pyridine, 1 g of dimethylsulfoxide, the solution is stirred for a further 5 hours.
50 ml of ether are added and the acetamidophenacylpyridinium chloride is collected by filtration. The obtained acetamidophenacylpyridinium chloride is dissolved in water, the solution is filtered, and then 1.7 g of concentrated hydrochloric acid is added. The solution is boiled for 1 hour, then cooled, acetone is added, and 4-aminophenacylpyridinium chloride hydrochloride is obtained by filtration.

Next, the obtained 4-aminophenacylpyri
2 g of dinium chloride hydrochloride in 15 g of water
And 4.5 g of a basic ion exchange resin (Ambe)
rlite IRA400-OH). After stirring,
After filtration to remove the ion exchange resin, 4-aminophena
An aqueous solution of silpyridinium chloride was obtained. 25g
1.3 g of 4-aminophenacylpyridinium chloride in water
The aqueous solution containing the lye is mixed with 1 g of silver nitrate for 90 minutes.
Reflux for minutes. The generated precipitate was removed by filtration. This
In addition, the specific surface area is 200m^Two/ G, DBPA is 122m
5 g of 1/100 g of carbon black are added and the mixture is
Heat to about 80 ° C., then add 0.52 g of concentrated hydrochloric acid and add
Then, a solution of sodium nitrite dissolved in a small amount of water
The liquid was added and the dispersion was stirred for another 1.5 hours. The result
As a result, NN having the structure shown below ⁺C₆H_FourCOCH_Two(N⁺
C_FiveH_Five) Group-containing diazonium salt,
Reacted with rack.

[0140]

Embedded image

As a result, C ₆ was added to the surface of carbon black.
The product with the H ₄ COCH ₂ (N ⁺ C ₅ H ₅ ) group was obtained.

Using the self-dispersible carbon black obtained above, black inks 1-1 and 1-2 having the following compositions were prepared. (Black ink 1-1)-5 parts of the above carbon black-10 parts of diethylene glycol-10 parts of trimethylolpropane-0.1 parts of acetylenol EH (trade name: manufactured by Kawaken Fine Chemical)-0.1 part of water-74.9 parts

(Black ink 1-2) 4 parts of the above carbon black 2 7 parts of glycerin 8 parts of 1,5-pentanediol 8 parts of ethylene glycol 7 parts of acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) 0 .2 parts ・ Water 73.8 parts

Cyan inks 1-1 to 1-4 were prepared using a mixture of the following constituent materials as an ink base. (Cyan ink base) ・ 7 parts glycerin ・ 10 parts triethylene glycol ・ 5 parts hexylene glycol ・ 3 parts DBL 199 ・ 1 part acetylenol EH (trade name: manufactured by Kawaken Fine Chemical)

(Cyan ink 1-1) 26 parts of the above base 74 parts of water

(Cyan Ink 1-2) 26 parts of the above base 2 parts of ammonium sulfate 0.3 parts of lithium hydroxide 71.7 parts of water

(Cyan Ink 1-3) 26 parts of the base described above. 1 part of citric acid. 4 parts of diethanolamine. 69 parts of water.

(Cyan Ink 1-4) 26 parts of the above base 1 part of sodium bicarbonate 2 parts of sodium carbonate 71 parts of water

Magenta inks 1-1 to 1-4 were prepared using a mixture of the following constituent materials as an ink base. (Magenta ink base) ・ 10 parts of triethylene glycol ・ 10 parts of urea ・ 4 parts of isopropyl alcohol ・ C. I. Acid Red 94 3 parts ・ Acetyleneol EH (trade name: manufactured by Kawaken Fine Chemical) 1 part

(Magenta Ink 1-1) 28 parts of the base 72 parts of water

(Magenta Ink 1-2) 28 parts of the above base 1.5 parts of ammonium succinate 3 parts of arginine 67.5 parts of water

(Magenta Ink 1-3) 28 parts of the above base 2.5 parts of ammonium acetate 0.4 parts of sodium hydroxide 69.1 parts of water

(Magenta Ink 1-4) 28 parts of the above base 1 part of succinic acid 4 parts of monoisopropanolamine 4 parts of water 67 parts

Yellow inks 1-1 to 1-4 were prepared using a mixture of the following constituent materials as an ink base. (Yellow ink base) 5 parts glycerin 10 parts 2-pyrrolidone 4 parts isopropyl alcohol I. Acid Yellow 23 3 parts ・ Acetyleneol EH (trade name: manufactured by Kawaken Fine Chemical) 1 part

(Yellow Ink 1-1) 23 parts of the above base 77 parts of water

(Yellow Ink 1-2) 23 parts of the above base 3 parts of lysine 74 parts of water

(Yellow Ink 1-3) 23 parts of the above base 2 parts of ammonium acetate 6 parts of triethanolamine 6 parts of water

(Yellow Ink 1-4) 23 parts of the above base 1.2 parts of ammonium benzoate 0.8 parts of ammonia 75 parts of water

<Examples 1 to 6, Comparative Examples 1 and 2> The ink sets obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were obtained by combining the inks obtained as described above in the combinations shown in Table 1. .

[0160]

[Table 1]

Here, it was determined whether or not the color ink used for each ink set had a buffering action against the change of the hydrogen ion concentration by adding 1.5 ml of a 1N aqueous sulfuric acid solution to 50 ml of the color ink. The measurement was performed by measuring the difference between the pH value of the ink thus obtained and the pH value of the ink in a state in which the aqueous sulfuric acid solution was not added. The results are shown in Table 2.
Table 2 shows the pH values of the black inks 1-1 and 1-2.

[0162]

[Table 2]

(Evaluation Method and Evaluation Criteria) Next, the ink set obtained above is applied to an ink jet recording apparatus having an on-demand type multi-recording head for discharging ink by applying thermal energy to the ink in accordance with a recording signal. Each was mounted on a modified machine of BJF 800 (manufactured by Canon), which was a device, and a printing test was performed to evaluate bleed between the black ink and the color ink. Table 3 shows the obtained results. The recording medium used for the printing test was Canon copy paper: PB PAPER, Xerox:
4024 PAPER, two types of plain paper.

(Bleeding between Black Ink and Each Color Ink) This is a printing method in which black ink and color ink are printed by the same scan. A pattern was printed in which solid portions of yellow, magenta, or cyan ink were adjacent. The evaluation criteria are as follows. Table 3 shows the obtained results. A: No bleed is visually observed at all boundaries. B: Slight bleed is visually observed, but not so much concern. C: Bleed is visually observed.

[0165]

[Table 3]

(Examples and Comparative Examples of Colorant-Encapsulated Resin-Containing Ink System) A colorant-encapsulated resin having a configuration in which a colorant is confined in a microcapsule for use in black ink was prepared as follows. did. (Microcapsule 1) C.I. I. Solvent Black 310 parts by weight ・ Styrene-N, N-dimethylaminoethyl methacrylate copolymer (molecular weight 40,000) 40 parts by weight ・ Methyl ethyl ketone 50 parts by weight First, the above-mentioned materials were mixed and dissolved. Next, the obtained mixture was subjected to phase inversion emulsification using acetic acid as a neutralizing agent, and methyl ethyl ketone was removed.
%, An aqueous dispersion of microcapsules having an average particle diameter of 0.08 μm was obtained. This is designated as microcapsule 1.

(Microcapsule 2) 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 40 Parts by weight First, the above-mentioned materials were mixed and dispersed. Next, the obtained mixture is subjected to phase inversion emulsification using acetic acid as a neutralizing agent, and methyl ethyl ketone is removed.
An aqueous dispersion of a carbon black-containing cationic resin having an average particle diameter of 0.10 μm was obtained. This is designated as microcapsule 2.

Using the self-dispersible carbon black obtained above and a resin (microcapsule) containing a colorant, black inks 2-1 to 2-4 having the following compositions were prepared. (Black ink 2-1) ・ 5 parts of the carbon black ・ 1.5 parts of the microcapsules 1 ・ 10 parts of glycerin ・ 10 parts of trimethylolpropane ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) 0.1 Part ・ Water 73.4 parts

(Black Ink 2-2) 5 parts of the carbon black 2 1.5 parts of the microcapsules 2 7 parts of glycerin 8 parts of 1,5-pentanediol 8 parts of ethylene glycol 7 parts of acetylenol EH (trade name) : Kawaken Fine Chemical) 0.2 parts ・ Water 71.3 parts

(Black Ink 2-3) ・ 5 parts of the above carbon black ・ 10 parts of diethylene glycol ・ 10 parts of trimethylolpropane ・ 0.1 part of acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) ・ 0.1 part of water 74.9 Department

(Black Ink 2-4) 4 parts of the above carbon black 2 7 parts of glycerin 8 parts of 1,5-pentanediol 8 parts of ethylene glycol 7 parts of acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) 0 .2 parts ・ Water 73.8 parts

Cyan inks 2-1 to 2-4 were prepared using a mixture of the following constituent materials as an ink base. (Cyan ink base) 7 parts glycerin 10 parts triethylene glycol 5 parts hexylene glycol C.I. I. Direct Blue 1993 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) 1 part

(Cyan ink 2-1) 26 parts of the above base 74 parts of water

(Cyan ink 2-2) 26 parts of the above base 2 parts of ammonium sulfate 2 parts of lithium hydroxide 0.3 parts of water 71.7 parts

(Cyan ink 2-3) 26 parts of the above base 1 part of citric acid 4 parts of diethanolamine 4 parts of water

(Cyan Ink 2-4) 26 parts of the above base 1 part of sodium bicarbonate 2 parts of sodium carbonate 71 parts of water

Magenta inks 2-1 to 2-4 were prepared using a mixture of the following constituent materials as an ink base. (Magenta ink base) ・ 10 parts of triethylene glycol ・ 10 parts of urea ・ 4 parts of isopropyl alcohol ・ C. I. Acid Red 94 3 parts ・ Acetyleneol EH (trade name: manufactured by Kawaken Fine Chemical) 1 part

(Magenta Ink 2-1) 28 parts of the above base 72 parts of water

(Magenta Ink 2-2) 28 parts of the above base 1.5 parts of ammonium succinate 3 parts of arginine 67.5 parts of water

(Magenta Ink 2-3) 28 parts of the above base 2.5 parts of ammonium acetate 0.4 parts of sodium hydroxide 69.1 parts of water

(Magenta Ink 2-4) 28 parts of the above base 1 part of succinic acid 4 parts of monoisopropanolamine 4 parts of water 67 parts

Yellow inks 2-1 to 2-4 were prepared using a mixture of the following constituent materials as an ink base. (Yellow ink base) 5 parts glycerin 10 parts 2-pyrrolidone 4 parts isopropyl alcohol I. Acid Yellow 233 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical) 1 part

(Yellow Ink 2-1) 23 parts of the above base 77 parts of water

(Yellow Ink 2-2) 23 parts of the above base 3 parts of lysine 74 parts of water

(Yellow ink 2-3) 23 parts of the above base 2 parts of ammonium acetate 6 parts of triethanolamine 6 parts of water

(Yellow Ink 2-4) 23 parts of the above base 1.2 parts of ammonium benzoate 0.8 parts of ammonia 75 parts of water

<Examples 7 to 12, Comparative Examples 3 and 4> The inks obtained above were combined in the combinations shown in Table 4 to obtain
The ink sets of Examples 7 to 12 and Comparative Examples 3 and 4 were obtained.

[0188]

[Table 4]

The color ink used for each ink set is
The pH value of an ink obtained by adding 1.5 ml of a 1N aqueous sulfuric acid solution to 50 ml of a color ink and the ink in a state where no aqueous sulfuric acid solution was added were determined as to whether or not a buffering effect was exerted on changes in the hydrogen ion concentration. Was determined by measuring the difference from the pH value. Table 5 shows the results. Table 5 shows the pH values of the black inks 2-1 to 2-4.

[0190]

[Table 5]

(Evaluation Method and Evaluation Criteria) Next, the ink set obtained above is applied to an ink jet recording apparatus having an on-demand type multi-recording head for discharging ink by applying thermal energy according to a recording signal to the ink. Each was mounted on a modified machine of BJF 800 (manufactured by Canon), which was a device, and a printing test was performed to evaluate bleed between the black ink and the color ink. Table 6 shows the obtained results. The recording media used in the printing test were two types of plain papers: Canon copy paper: PB PAPER and Xerox: 4024 PAPER.

(Bleeding between Black Ink and Each Color Ink) This is a printing method in which black ink and color ink are printed by the same scan. The pattern was printed such that the solid portion was adjacent to the solid portion of yellow, magenta, or cyan ink. The evaluation criteria are as follows. Table 6 shows the obtained results. A: No bleed is visually observed at all boundaries. B: Slight bleed is visually observed, but not so much concern. C: Bleed is visually observed.

[0193]

[Table 6]

Next, using the black inks of the ink sets of Examples 7 to 12, each of the two types of plain paper was
A solid portion was formed in the same manner as in the bleeding test. After a lapse of 4 hours, put the silbon paper on the printed paper, put a weight of 5 cm on a side and weigh 1 kg on it, and then pull the silbon paper. It was visually observed whether or not the printed portion of the silbon paper was stained by rubbing. As a result, no stain was observed on both the white background and the silk paper.

Further, using the black inks of the ink sets of Examples 7 to 12, each of the two types of plain paper was
Characters were printed using the above ink jet recording apparatus. After one hour, the character portion is traced once with normal pen pressure using a yellow highlighter pen spot writer yellow manufactured by Pilot Co., Ltd. to bleed the printed portion, stain a white background portion around the character, and further pen the highlighter. The presence or absence of the previous stain was visually observed. As a result, the bleeding and dirt were not recognized. From this, it was proved that the black ink according to the second embodiment of the present invention was also excellent in scratch resistance and marker resistance.

[0196]

As described above, according to the present invention,
Ink set for color ink jet recording and ink jet recording satisfying various performances such as print quality and image fastness required of black ink, and in which the black ink does not cause bleeding with other color inks Methods and apparatus are provided. Further, according to the present invention, a color that satisfies various performances such as print quality and image fastness required for a black ink, and that does not cause bleeding between the black ink and another color ink. An ink jet recording ink set, an ink jet recording method, and an apparatus are provided. or,
According to the present invention, since a black ink contains a resin containing a colorant, high-quality ink jet recording excellent in abrasion resistance and line marker resistance without impairing the reliability as an ink for ink jet recording. Images can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a vertical and horizontal view of an ink jet recording apparatus head.

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

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

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

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

FIG. 7 is a perspective view showing an ink jet recording apparatus.

8 is a perspective view showing the recording head unit of FIG.

FIG. 9 is an enlarged sectional view of the vicinity of a heating element of a recording head.

FIG. 10 is a schematic perspective view illustrating a main part of an example of an ink jet printer on which a liquid discharge head can be mounted.

FIG. 11 is a schematic perspective view showing an example of an ink jet cartridge provided with a liquid ejection head.

FIG. 12 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. 13 is a conceptual diagram illustrating a part of an example of the liquid ejection head illustrated in FIG. 11;

FIG. 14 is an enlarged view of a discharge port shown in FIG.

FIG. 15 is a schematic diagram showing the state of ink attachment at the ejection port shown in FIG. 14;

FIG. 16 is a schematic diagram of a main part in FIG.

17 corresponds to a perspective sectional shape taken along line XX in FIG. 16 and FIG.
FIG. 25 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 8 to 24.

FIG. 18 corresponds to the perspective sectional shape taken along line XX in FIG. 16;
FIG. 25 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time, together with FIG. 7 and FIGS.

19 corresponds to a perspective sectional shape taken along line XX in FIG. 16 and FIG.
FIG. 27 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time, together with FIG. 7, FIG. 18, and FIGS.

FIG. 20 corresponds to a perspective sectional view taken along line XX in FIG. 16;
FIG. 25 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 7 to 19 and FIGS.

FIG. 21 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 25 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 7 to 20 and FIGS.

FIG. 22 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 27 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 7 to 21 and FIGS.

FIG. 23 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 25 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS. 7 to 22 and 24.

FIG. 24 corresponds to a perspective sectional shape taken along line XX in FIG.
FIG. 24 is a schematic cross-sectional view for explaining the liquid discharging operation of the liquid discharging head with time along with FIGS.

FIG. 25 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.

[Explanation of symbols]

13: Head 14: Ink Groove 15: Heating Head 16: Protection Film 17: Aluminum Electrode 18: Heating Resistor Tank 19: Heat Storage Layer 20: Substrate 21: Ink 22: Discharge Orifice (Micro Hole 23: Meniscus 24: Ink Drop 25) : Recording medium 26: Multi-groove 27: Glass plate 28: Heating head 31: Heating element 32: Liquid chamber 33: Substrate 34: Partition wall 35: Ink droplet 36: Protective film 37: Discharge port 38: Ink liquid path 40: Ink Bag 42: stopper 44: ink absorber 45: ink cartridge 51: paper supply unit 52: paper feed roller 53: paper discharge roller 61: blade 62: cap 63: ink absorber 64: ejection recovery unit 65: recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Air communication port 100: inkjet print head 101: air bubble 102: print head 103: print head unit 104: guide shaft 105: guide shaft 106: print medium 107: switch section and display element section 108: platen 109: feed roller 110: recovery system unit 111 : Carriage 20Bk, 20C, 20M, 20Y: Ink tank 600: Inkjet recording device 601: Inkjet head cartridge 602: Driving motor 603, 604: Driving force transmission gear 605: Lead screw 606: Spiral groove 607: Carriage 607a: Lever 608 : Guide 609: Platen roller 610: Paper holding plate 611, 612: Photocoupler 613: Support member 614: Cap member 615: Ink suction means 616: Opening inside cap 617: Leaning blade 618: Moving member 619: Main body support 620: Lever 621: Cam 832: Discharge port 832a: Initiating portion 832b: Depressed portion 931: Electrothermal conversion element (heater, ink discharge energy generating element) 933: Ink supply port (opening) 934: Substrate 935: Orifice plate (discharge port plate) 935a: Discharge port surface 936: Ink flow path wall 936a: Partition wall 940: Discharge port 1337: Bubble chamber 1338: Liquid flow path 1141: Groove 1141a: Top 1004: Meniscus 1001: Liquid tank 1006: Movement 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: drive 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 ion 2709 : Sodium ion C: wet ink F _M : meniscus retreat direction F _C : direction opposite to meniscus retreat direction G: center of gravity I: ink Ia: main droplet (liquid, ink) Ib, Ic: liquid (ink) Id: in groove Adhered ink (ink in groove) Ie: ink remaining in liquid flow path L: line from liquid chamber (ink supply port) to discharge port N ₁ : width dimension of foaming chamber N ₂ : width of foaming chamber Length dimension O: Center of discharge port P ': Recording medium P: Transport of paper Feeding direction R: rotation direction of the belt S: Direction T ₁ substantially orthogonal to the conveying direction of the paper: the discharge port saphenous section dimensions w: width of the partition wall

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuko Yakushigawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshihisa Takizawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Non Corporation

Claims (25)

[Claims] 1. An ink set for recording a color image on a recording medium using at least two colors of ink including at least a black ink and a color ink, wherein the black ink has at least one type of color material on its surface. The self-dispersible carbon black in which a cationic group is bonded directly or through another atomic group, and the color ink has an anionic substance and has a buffering action against a change in hydrogen ion concentration An ink set characterized by having: 2. The ink set according to claim 1, wherein the black ink further contains a resin containing a colorant. 3. The ink set according to claim 1, wherein the colorant is a water-insoluble dye or pigment. 4. The ink set according to claim 2, wherein the resin is a resin having a cationic hydrophilic group on a surface. 5. The ink set according to claim 2, wherein the colorant has substantially the same color as a colorant contained in the black ink. 6. The ink set according to claim 2, wherein the resin containing the colorant has a configuration in which the colorant is confined in microcapsules made of the resin. 7. The pH value of the color ink is adjusted so that the difference between the pH value when 1.5 ml of a 1N aqueous sulfuric acid solution is added to 50 ml of the color ink and the pH value before the addition is within 1.0. The ink set according to any one of claims 1 to 6, wherein the ink set is adjusted to: 8. The cationic group on the surface of the self-dispersible carbon black is a primary amine group, a secondary amine group, a tertiary amine group, a quaternary ammonium group or a quaternary phosphonium group. 8. The ink set according to any one of 1 to 7. 9. The ink set according to claim 1, wherein the anionic substance contained in the color ink is an anionic dye. 10. The ink set according to claim 1, wherein the pH of the color ink is higher than the pH of the black ink. 11. The ink set according to claim 10, wherein the pH of the black ink has a value in an acidic region, and the pH of the color ink has a value in a neutral region to a basic region. 12. The color ink according to claim 1, wherein the color ink contains at least one member selected from the group consisting of an ammonium salt and an amine salt of an organic acid or an inorganic acid, and has a basic pH.
2. The ink set according to 1. 13. The ink set according to claim 1, wherein the color ink contains at least one selected from the group consisting of ammonia and a basic amino compound. 14. The ink set according to claim 1, wherein the ink set is for color inkjet recording. 15. A black ink containing a self-dispersion type carbon black having a cationic group bonded to a surface thereof directly or via another atomic group as a coloring material is ejected from an orifice in accordance with a recording signal. And applying to a recording medium; and discharging an ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration from an orifice according to a recording signal.
An inkjet recording method, comprising at least a step of applying the recording medium to a recording medium. 16. The ink jet recording method according to claim 15, wherein the ink is ejected from an orifice by applying thermal energy to the ink. 17. A black ink containing section containing a black ink containing a self-dispersible carbon black having a cationic group bonded to the surface thereof directly or via another atomic group as a coloring material. A color ink containing section containing a color ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration, and a head for discharging each of the black ink and the color ink A recording unit comprising at least a unit. 18. The recording unit according to claim 17, wherein said head section is a head for ejecting ink droplets by applying thermal energy to ink. 19. The ink container according to claim 19, wherein
The recording unit according to claim 17, wherein the recording unit is formed of cellulose, polyvinyl acetate, or a polyolefin resin. 20. A black ink containing section containing a black ink containing a self-dispersible carbon black having a cationic group bonded to the surface directly or via another atomic group as a coloring material. And an ink cartridge containing a color ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration. 21. The ink cartridge according to claim 20, wherein the ink container has a liquid contact surface formed of polyolefin. 22. A black ink containing portion containing a black ink containing a self-dispersible carbon black having a cationic group bonded to the surface thereof directly or via another atomic group as a colorant. And a color ink containing section containing a color ink containing an anionic substance and having a buffering action against a change in hydrogen ion concentration, and a head for ejecting the black ink and the color ink, respectively. An ink jet recording apparatus comprising at least a unit. 23. The head according to claim 2, wherein the head is a head for ejecting ink droplets by applying thermal energy to the ink.
3. The ink jet recording apparatus according to 2. 24. The ink container according to claim 24, wherein:
The ink jet recording apparatus according to claim 23, wherein the ink jet recording apparatus is formed of cellulose, polyvinyl acetate, or polyolefin resin. 25. A method for alleviating bleed in a boundary area between a black image and a color image formed on a recording medium by an ink-jet method, wherein at least one type of color material is used as a color material on the surface for forming the black image. Using a black ink containing a self-dispersible carbon black in which the cationic group is bonded directly or via another atomic group, the above-mentioned color image is formed with an anionic substance, and a hydrogen ion A method for alleviating bleed, characterized by using a color ink having a buffering action against a change in density.