JP2002226742A - Ink set, ink jet recording method using the same, recording unit, ink cartridge and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet ink set capable of forming an image excellent in light resistance and ozone resistance even when a light-colored ink is used for forming a halftone image. SOLUTION: The ink set comprises at least one color ink composed of at least two inks having a different color material concentration, where one ink of the lower color material concentration contains a pigment, which is a self- dispersing pigment having at least one hydrophilic group bonded to the surface thereof directly or via another atomic group, and the other ink of the higher color material concentration contains a dye. In the recording method, the ink set is employed. There are also provided a recording unit, an ink cartridge and an ink jet recording apparatus, each having incorporated the ink set therewith.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink set used for ink-jet recording, and more particularly, to a light-and-shade ink method using a pigment and a dye as a coloring material. And an ink set for providing an image having ozone resistance.

[0002]

2. Description of the Related Art An ink jet recording method has attracted attention as one of non-impact technologies that can be easily made full color. In particular, video printers that print out video images and computer graphics (CG)
The printer's recording method for printing out a hard copy of the printer includes the printer's texture (texture), color reproducibility,
Suitable for rich color tone.

Various ink jet recording methods have been proposed. Ink jet recording methods using two or more inks having different dye concentrations for at least one of each of yellow, magenta, cyan, and black inks. (Dark ink method) is disclosed in Japanese Patent Publication No. 02-014905. According to the above method, since the highlight ink (light ink) and the dark ink (dark ink) are used, smooth color reproduction is possible over a wide density range from the highlight portion to the dark portion of the image.

[0004]

However, in the above-mentioned dark and light ink method, the use of the dye light ink has a great merit in image formation, but has a problem in light fastness of the formed image. That is, there is a problem that the image portion using the light dye ink has lower light resistance than the image portion using the dark ink.

[0005] In general, ink-jet recording is often carried out using an aqueous ink, that is, a water-soluble dye as a recording agent, and is excellent in image color tone.
Many of the images had a problem with light fastness, and there was a difficulty in selecting a dye. In particular, when a dye-dense ink is used at a certain density or higher, it is relatively robust, but when it is used in a low-density region as a dye-dense ink, fading occurs and image fastness is insufficient. Was.

[0006] The problem of light fastness peculiar to the dye light ink is considered to be caused by the aggregation state of the dye molecules. That is, dye molecules in a high concentration state have a large aggregate of many molecules in the ink, and even when this is recorded on a recording paper, a relatively large molecular association state is maintained. It is considered to show excellent light fastness. However, when the dye concentration is low, that is, in the case of a light ink, even if an aggregate of molecules is formed, the size is as small as about several molecules, so that a sufficient aggregate state cannot be taken even on the recording paper, It is considered that they are easily attacked by radical species or active oxygen (singlet oxygen) generated by light and have low light resistance.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink-jet ink set capable of forming an image having excellent light resistance and ozone resistance even when a light ink is used for forming a halftone image.

[0008]

The above object is achieved by the present invention described below. That is, the present invention provides a color ink set for recording an image on a recording material by an ink jet recording method, wherein at least one color ink is composed of two or more types of inks having different color material densities, An ink set is characterized in that a pigment is used and a dye is used in an ink having a high coloring material concentration. The pigment used in the present invention is a self-dispersed pigment in which at least one hydrophilic group is bonded directly or via another atomic group to the surface of the pigment. The one color shown in the present invention refers to one showing the same hue,
There is no particular limitation on hue. The preferred hues are yellow, magenta, cyan, black, red, green,
Blue, orange, brown and the like.

In the ink set of the present invention, the concentration of a pigment used as a light ink is 1% or less, and the concentration of a dye used as a dark ink is 1% or more. The ink set is preferably made of ink having a color tone.

[0010] The present invention also relates to an ink jet recording method in which ink is jetted onto a recording material to perform recording, wherein the ink set described above is used. As the recording material, plain paper can be used, but preferably, a coating support containing at least a hydrophilic polymer and / or an inorganic porous material is applied.

According to the present invention, there is provided a recording unit provided with an ink storing section for storing ink and a head section for discharging the ink, wherein the ink is the ink set described above. It is about.

[0012] The present invention also relates to an ink cartridge provided with an ink containing section containing ink, wherein the ink is the ink set described above.

According to the present invention, there is provided an ink jet recording apparatus comprising a recording unit having an ink containing section for containing ink and a head section for discharging the ink as ink droplets by the action of thermal energy. An ink jet recording apparatus, which is the ink set described above.

According to the present invention, there is provided an ink jet recording apparatus including an ink cartridge having an ink storing section for storing ink, and a head section for discharging the ink by the action of thermal energy. The present invention relates to an ink jet recording apparatus characterized in that it has an ink supply unit for supplying the ink contained in an ink cartridge to the recording head.

According to the present invention, when a photographic image is formed by an ink-jet method, a pigment is used for a light ink, thereby maintaining the same color tone as when a dye is used as a light ink, and the light fastness of the obtained image. The self-dispersion pigment used in the present invention is excellent in color tone and ejection stability.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

[Function] In the present invention, an ink jet image is formed by applying a light ink using a pigment as a coloring material to a highlight portion of an image and a dark ink using a dye as a coloring material to a dark portion. As a result, while maintaining the same color tone as the dark and light ink set using only the dye, an image having higher robustness can be formed as compared with the image formation using the dark and light ink set using only the dye.

When a dark and light ink set using only a pigment as a coloring material is used, the formation of an image in a dark portion with a dark ink has an excellent effect on image fastness as compared with the case where a dye is used. , Inferior in color tone, especially in transparency. However, when the pigment ink is used at a low concentration such as 1% by weight or less,
The color tone, especially the transparency, is greatly improved as compared with the case where a pigment ink having a high concentration that can be used for forming an image in a dark area is used.

In the case of a light ink using a dye, the size of the aggregate of molecules is as small as several molecules, so that a sufficient aggregation state cannot be obtained even on recording paper, and radical species or active oxygen generated by light are not obtained. (Singlet oxygen) and the like, it is considered that they are easily attacked and have low lightfastness.However, even at a low concentration, the pigment forms larger particles than the aggregate of the dye molecules. Compared to when
Light resistance and ozone resistance are greatly improved.

A major feature of the self-dispersion pigment in the present invention is that such a self-dispersion pigment has a surface property modified to be hydrophilic, so that the vicinity of the pigment surface has a dye-like property and has a color tone. Is also close to a dye.

For example, in Japanese Patent Application Laid-Open No. H11-105308, in order to achieve water resistance on plain paper, in a dark and light ink method, an anionic dye ink is used as a dark ink, a pigment ink is used as a light ink, and a dye ink is used. A technique is disclosed in which a cationic substance is applied to but not applied to pigment ink, but the above invention can realize water resistance on plain paper, but is used in the present invention. It does not improve the color tone of the pigment that can be achieved with a self-dispersing pigment.

In order to use a pigment as a coloring material of an aqueous ink, it is required that the pigment be stably dispersed in an aqueous medium. Generally, pigments have poor dispersibility, and a method of adding a dispersant and dispersing the pigment in an aqueous medium has been adopted to obtain a uniform dispersion system. However, even with the method using this dispersant, satisfactory dispersibility cannot be obtained, and there is a problem that the ink in which the pigment is dispersed is particularly poor in long-term storage.

On the other hand, in general, when ink is used for ink jet recording, it is required that the ink be ejected from the fine tip of the ink jet recording head as stable droplets. It is necessary that solidification of the ink does not occur due to drying of the orifice. However, when the ink containing the above-mentioned dispersant is used for ink jet recording, the resin forming the dispersant adheres to the orifice or the like and is not redissolved. Etc. may occur. In addition, the aqueous pigment ink containing a dispersant is viscous, causing resistance in the path to the nozzle tip when performing continuous ejection and high-speed printing over a long period of time, making ejection unstable, making smooth recording difficult. There was a problem of becoming.

However, the self-dispersible pigment used in the present invention can be stably dispersed without using a dispersant by introducing a water-soluble group on the surface of the pigment.
The degree of freedom also increases for ink design. In particular, when a halftone photographic image is formed by the ink set of the present invention on an inkjet-coated paper or the like coated with a porous inorganic oxide such as silica, not only light resistance and ozone resistance are excellent, The color tone is remarkably improved as compared with the case where an image is formed on plain paper, and a color tone image which is the same as the case where a halftone photographic image is formed with a dark and light ink set using only dye as a color material is formed be able to.

[Embodiments] Next, preferred embodiments of the present invention will be described, and the present invention will be described in more detail.

[Self-dispersing Pigment] First, in the aqueous ink of the present invention, first, as a coloring material, a self-dispersing pigment in which at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group. A dispersion pigment is used. As a result, unlike a conventional ink, a dispersant for dispersing a pigment is not required. The self-dispersing pigment used in the present invention is preferably an ionic pigment, and more preferably an anionic one or a cationic one.

In the case of an anionically charged pigment, the hydrophilic group bonded to the surface is, for example, -COOM, -SO _{3
M, -PO 3 HM, -PO 3} M 2, -SO 2 NH 2, -SO 2 NH
COR or the like (where M is a hydrogen atom, an alkali metal,
R represents an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group; ). In the present invention, among these, it is particularly preferable to use those in which —COOM and —SO ₃ M are bonded to the pigment surface and are anionically charged.

The "M" in the hydrophilic group may be, for example, lithium, sodium, potassium or the like as an alkali metal, and mono to trimethyl ammonium, mono to triethyl ammonium, mono to triethyl ammonium as organic ammonium. Trimethanol ammonium. As a method of obtaining an anionically charged pigment,
As a method of introducing -COONa on the pigment surface, for example,
A method of oxidizing the pigment with sodium hypochlorite may be mentioned, but of course, the present invention is not limited to these.

In the case of a cationically charged pigment, the hydrophilic group bonded directly or via another atomic group is, for example, preferably a quaternary ammonium group, and more preferably, a quaternary ammonium group. Those in which any of the quaternary ammonium groups are bonded to the surface of the raw material are preferably used as the coloring material.

-COOM, -SO ₃ M, -SO ₂ NH ₂ , -PO ₃ HM, -PO ₃ M ₂ , -SO ₂ NHCOR, -NH ₃ ⁺ , -NR ₃ ⁺ ,

[0031]

Embedded image

As a method of producing a cationic self-dispersion pigment having a hydrophilic group as described above, for example, as a method of bonding an N-ethylpyridyl group having the structure shown below, 3-amino Examples include a method of treating with -N-ethylpyridinium bromide, but of course, the present invention is not limited to this.

[0033]

Embedded image

In the present invention, it is preferable to use one in which a hydrophilic group is bonded to the surface of the pigment via another atomic group. Other atomic groups include, for example, 1 to 12 carbon atoms.
And a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group. Specific examples of the hydrophilic group bonded to the surface of the pigment via another atomic group include, in addition to those described above, for example, -C ₂ H ₄ COOM, -PhSO ₃ M, -PhCOOM, etc.
(Where Ph represents a phenyl group). As a method of introducing a hydrophilic functional group on the surface of the pigment, for example, a method of diazotizing p-aminobenzenesulfonic acid into the pigment may be mentioned, but of course, the present invention is not limited to these. When a hydrophilic functional group is introduced by diazotization as described above, it is desirable that the pigment does not have a primary amine.

The self-dispersion type pigment used in the aqueous ink of the present invention is cationically or anionically charged by the hydrophilic group on the surface of the raw material, and has water dispersibility due to repulsion of the ion. The hydrophilicity is also improved by the functional group. Therefore, an aqueous pigment ink that is stably dispersed in an aqueous medium without increasing the particle size or viscosity of the pigment even after being left for a long time is obtained.

In the present invention, the above-mentioned self-dispersing pigment is not limited to one kind, and the color tone may be adjusted by using a mixture of two or more kinds.

(Black Pigment: Carbon Black) As a raw material used for the black ink, carbon black is preferably used. For example, carbon black pigments such as furnace black, lamp black, acetylene black, and channel black, for example, Rayvan (Raven) 700
0, Ray-Van 5750, Ray-Van 5250, Ray-Van 50
00 ULTRA-, Ray-Van 3500, Ray-Van 2000, Ray-Van 1500, Ray-Van 1250, Ray-Van 1200, Ray-Van 1190 ULTRA-II, Ray-Van 1170, Ray-Van 1255 (all manufactured by Columbia), Black Pearls (Bla
ck Pearls) L, Regal 400R, Legal 330
R, Regal 660R, Mogul L, Monak (Mo
narch) 700, Monak 800, Monak 880, Monak 900, Monak 1000, Monak 1100, Monak 1300, Monak 1400,
Valcan XC-72R (all manufactured by Cabot Corporation),
Color Black (Color Black) FW1, Color Black FW2, Color Black FW2V, Color Black F
W18, color black FW200, color black S150,
Color Black S160, Color Black S170, PRINTEX 35, PRINTEX U, PRINTEX V, PRINTEX 140U, PRINTEX 140V,
Special Black (Special Black) 6, Special Black 5, Special Black 4A, Special Black 4 (from Degussa), No. 25, No. 33, No. 40,
No.47, No.52, No.900, No.2300, MCF-88, MA
600, MA7, MA8, MA100 (all manufactured by Mitsubishi Chemical Corporation)
New prototypes can be used for the present invention, but are not limited to them.

(Organic pigment) Specific examples of the organic pigment include toluidine red, toluidine maroon, Hansa Yellow,
Benzidine yellow, insoluble azo pigments such as pyrazolone red, soluble azo pigments such as litol red, helio bordeaux, pigment scarlet, permanent red 2B, alizarin, indanthrone, derivatives from vat dyes such as thioindigo maroon, phthalocyanine blue, Phthalocyanine pigments such as phthalocyanine green, quinacridone red, quinacridone pigments such as quinacridone magenta, perylene pigments such as perylene red and perylene scarlet, isoindolinone yellow,
Isoindolinone pigments such as isoindolinone orange, imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange, benzimidazolone red, pyranthrone pigments such as pyranthrone red and pyranthrone orange, thioindigo pigments, condensation Azo pigments, diketopyrrolopyrrole pigments, flavanthrone yellow, acylamide yellow, quinophthalone yellow,
Other pigments such as nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, and dioxazine violet can be exemplified.

In addition, the organic pigment is used as a color index (C.I.
I.) Number, CI Pigment Yellow 1
2, 13, 14, 17, 20, 24, 74, 83, 86, 93, 97, 109, 11
0, 117, 120, 125, 128, 137, 138, 147, 148, 150, 15
1, 153, 154, 166, 168, 180, 185, CI Pigment Orange 16, 36, 43, 51, 55, 59, 61, 71, CI Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 14
9, 168, 175, 176, 177, 180, 192, 215, 216, 217, 22
0, 223, 224, 226, 227, 228, 238, 240, 254, 255, 27
2, CI Pigment Violet 19, 23, 29, 30, 3
7, 40, 50, C.I. Pigment Blue 15, 15: 1, 15:
3, 15: 4, 15: 6, 22, 60, 64, CI Pigment Green 7, 36, CI Pigment Brown 23, 25, 26 and the like.

Particularly, among these pigments, CI Pigment Yellow 74, 93, 97, 110, 120, 128, 138, 147,
148, 150, 151, 154, 180, 185, CI Pigment Red 122, CI Pigment Violet 19, CI Pigment Blue 15, 15: 1, 15: 3, 15: 4 and the like. preferable.

[(Water-soluble) dye ink] The dye ink used in the present invention preferably uses a water-soluble dye containing an anionic group as a coloring material.

The water-soluble dye having an anionic group used in the present invention includes a color index (COLOUR IN).
Any water-soluble acid dye, direct dye and reactive dye described in (DEX) can be used without any particular limitation. Further, dyes not described in the color index can be used without particular limitation as long as they have an anionic group such as a sulfone group and a carboxyl group. It should be noted that the water-soluble dyes mentioned here include those having a pH dependency of solubility.

Next, examples of the water-soluble dye having an anionic group which can be used in the present invention include the following.

(Water-Soluble Black Ink) Examples of dyes used in black ink include CI Direct Black 17, CI Direct Black 19, CI Direct Black 22, and CI Direct Black. 31, C.I.
Direct Black 32, C.I.Direct Black 5
1, CI direct black 62, CI direct black 71, CI direct black 74, CI direct black 112, CI direct black 113, CI direct black
Direct Black 154, C.I.Direct Black 16
8, C.I. Acid Black 2, C.I. Acid Black
48, C.I. Acid Black 51, C.I. Acid Black 52, C.I. Acid Black 110, C.I. Acid Black 115, C.I. Acid Black 156, C.I. Reactive Black 1 , CI Reactive Black 8, C.I.
I. Reactive Black 12, C.I. Reactive Black 13, C.I. Food Black 1, C.I. Food Black 2
And the like.

(Water-soluble yellow ink) Examples of dyes used in the yellow ink include CI Acid Yellow 11, CI Acid Yellow 17, CI Acid Yellow 23, and CI Acid Yellow. 25, C.I. Acid Yellow 29, C.I. Acid Yellow 42, C.I. Acid Yellow 49, C.I. Acid Yellow 61, C.I. Acid Yellow 71, C.I.Direct Yellow 12, C.I.
Direct Yellow 24, C.I.Direct Yellow 2
6, C.I.Direct Yellow 44, C.I.Direct Yellow 86, C.I.Direct Yellow 87, C.I.Direct Yellow 98, C.I.Direct Yellow 100, C.I.Direct Yellow 130, C.I.Direct Yellow 142
And the like.

(Water-soluble magenta ink) The dyes used in the magenta ink include CI Acid Red 1 and C.I.
I. Acid Red 6, C.I. Acid Red 8, C.I. Acid Red 32, C.I. Acid Red 35, C.I. Acid Red 37, C.I. Acid Red 51, C.I. Acid Red 52, C.I. Acid Red 80, C.I. Acid Red 85, C.I. Acid Red 87, C.I. Acid Red 92, C.I. Acid Red 94, C.I. Acid Red 115, C.I. Acid Red 180, C.I. Acid Red 254, C.I. Acid Red 256, C.I. Acid Red 289, C.I. Acid Red 315, C.I. Acid Red 317, C.I. Direct Red 1, C.I. Direct Red 4, C.I. Direct Red 13, C.I. Direct Red 17, C.I. Direct Red 23, C.I. Direct Red 28, C.I. I. Direct Red 31, C.I. Direct Red 62, C.I. Direct Red 79, C.I. Direct Red 81, C.I. Direct Red 83, C.I. Direct Red 89, C.I. Direct Red 227, C.
I. Direct Red 240, C.I. Direct Red 24
2, CI Direct Red 243 and the like.

(Water-soluble cyan ink) The dyes used for the cyan ink include CI Acid Blue 9, CI Acid Blue 22, CI Acid Blue 40, CI Acid Blue 59, and CI Acid Blue 59. C.I. Acid Blue 93, C.I. Acid Blue 102, C.I. Acid Blue 104, C.I. Acid Blue 113, C.I. Acid Blue 117, C.I. Acid Blue 120, C.I. I. Acid Blue 167, C.I. Acid Blue 229, C.I. Acid Blue 234, C.I. Acid Blue 254, C.I.Direct Blue 6, C.I. Direct Blue 22, C.I. Direct Blue 25, C.I.Direct Blue 71, C.I.Direct Blue 78, C.I.Direct Blue 86, C.I.Direct Blue 90, C.I.
Direct Blue 106, C.I. Direct Blue 199 and the like.

Further, other dyes that can be used include those described in JP-A-6-25573 and EP 048647.
A1, EP 0468648 A1, and EP 0468
649A1 can also be used.

(Aqueous Medium) The aqueous medium contained in the aqueous ink of the present invention comprises a mixed solvent of water and a water-soluble organic solvent. As the water-soluble organic solvent, those having an effect of preventing drying of the ink are particularly preferred. Preferably, it is desirable to use deionized water instead of general water containing various ions.

As the water-soluble organic solvent used in the present invention, specifically, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, te
C1-C5 alkyl alcohols such as rt-butyl alcohol, isobutyl alcohol and n-pentanol;
Amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and polyethylene Oxyethylene or oxypropylene copolymers such as glycols and polypropylene glycols; alkylene groups such as ethylene glycol, propylene glycol, trimethylene glycol, triethylene glycol, 1,2,6-hexanetriol have 2 to 6 carbon atoms Alkylene glycols; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or Ethyl) ether, lower alkyl ethers such as triethylene glycol monomethyl (or ethyl) ether; triethylene glycol dimethyl
(Or ethyl) ether, lower dialkyl ethers of polyhydric alcohols such as tetraethylene glycol dimethyl (or ethyl) ether; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; sulfolane, N-methyl-2-pyrrolidone ,
2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. The water-soluble organic solvents as described above can be used alone or as a mixture.

The content of the above water-soluble organic solvent contained in the aqueous ink of the present invention is not particularly limited, but is preferably in the range of 3 to 50% by weight based on the total weight of the ink. Also, the content of water contained in the ink,
It is preferably in the range of 50 to 95% by weight based on the total weight of the ink. In addition, the aqueous ink of the present invention may further include, as necessary, additives such as a viscosity modifier, an antifoaming agent, a preservative, and a fungicide in order to obtain an ink having desired physical properties. Surfactants, antioxidants and the like can be added. The choice of surfactant depends on the surface tension of the ink.
It is preferable to determine so as to be 0 mN / m or more.

[Recording Material] The ink set of the present invention comprising a combination of the pigment ink and the dye ink as described above can be used not only for an uncoated recording medium such as plain paper but also for at least a hydrophilic polymer and / or Particularly excellent effects are exhibited when an image is formed on a recording medium comprising a coating support containing an inorganic porous material. That is, the hydrophilic polymer or the inorganic porous material constituting the ink receiving layer of such a recording medium is formed of an organic pigment by chemical or physical action via oxygen, ozone, various light sources, and the like in the atmosphere. Although there is a tendency to promote light fading, if an image is formed using the ink set of the present invention, an image satisfying light resistance can be obtained.

(Ink Receiving Layer) As the hydrophilic polymer constituting the ink receiving layer of the recording medium, a conventionally known substance can be used. For example, starch, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, alginic acid, gelatin, polyvinyl alcohol, polyvinyl acetal, polyethylene oxide, sodium polyacrylate, cross-linked polyacrylic acid, polyvinyl methyl ether, polystyrene sulfonic acid, quaternary Examples thereof include polyvinyl pyridine, polyacrylamide, polyvinyl pyrrolidone, polyamine, aqueous urethane resin, water-soluble acrylic resin, water-soluble epoxy compound, and water-soluble polyester. Further, a modified product of the above polymer,
For example, ion-modified products such as cation-modified polyvinyl alcohol and cation-modified polyvinylpyrrolidone can be used as appropriate. Further, examples of the inorganic porous material used for forming the ink receiving layer of the recording medium include silica gel, alumina, zeolite, and porous glass.

[Inkjet Recording Method and Apparatus] As described above, the aqueous ink of the present invention is particularly effective when used in inkjet recording. Ink jet recording methods include a recording method in which mechanical energy is applied to the ink to discharge the ink, and an ink jet recording method in which thermal energy is applied to the ink to discharge the ink by foaming of the ink. The aqueous ink of the present invention is particularly suitable.

Next, an example of the ink jet recording apparatus of the present invention suitable for performing recording using the above-described aqueous ink of the present invention will be described below.

(Inkjet Recording Apparatus Utilizing Thermal Energy) First, an example of the configuration of a head which is a main part of an inkjet recording apparatus utilizing thermal energy is shown in FIGS.

FIG. 1 is a sectional view of the head 13 along the ink flow path, and FIG. 2 is a sectional view taken along the line AB in FIG. The head 13 is obtained by adhering a heating element substrate 15 to a glass, ceramic, silicon or plastic plate having a flow path (nozzle) 14 for passing ink. The heating element substrate 15 has a protective layer 16 made of silicon oxide, silicon nitride, silicon carbide, etc., electrodes 17-1 and 17-2 made of aluminum, gold, aluminum-copper alloy, etc., and Hf.
A heating resistor layer 18 formed of a high melting point material such as B ₂ , TaN, TaAl, a heat storage layer 19 formed of thermally oxidized silicon, aluminum oxide, or the like; a material having good heat dissipation properties such as silicon, aluminum, aluminum nitride, etc. Substrate to be formed 20
Is made up of

When a pulse-like electric signal is applied to the electrodes 17-1 and 17-2 of the head 13, the heating element substrate 15
In the area indicated by n, heat is generated rapidly, and bubbles are generated in the ink 21 in contact with this surface.
23 protrudes, the ink 21 is ejected through the nozzle 14 of the head, becomes an ink droplet 24 from the ejection orifice 22, and flies toward the recording material 25. FIG. 3 shows FIG.
1 is an external view of an example of a multi-head in which a number of heads shown in FIG. This multi-head is formed by bonding a glass plate 27 having a multi-nozzle 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 this head. In FIG. 4, reference numeral 61 denotes a blade serving as a wiping member, one end of which is held and fixed by a blade holding member to form a cantilever. The blade 61 is arranged at a position adjacent to a recording area of the recording head 65, and in this embodiment, is held in a form protruding into the movement path of the recording head 65.

Numeral 62 denotes a cap on the projecting opening surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, and comes into contact with the ink discharge opening surface. And a configuration for performing capping. Further, reference numeral 63 denotes an ink absorber provided adjacent to the blade 61, similar to the blade 61.
The recording head 65 is held in a protruding form in the movement path. The above blade 61, cap 62 and ink absorber
The discharge recovery section 64 is composed of 63 and the blade 61
In addition, the ink absorber 63 removes moisture, dust, and the like from the ejection port surface.

Numeral 65 has discharge energy generating means,
A recording head 66 that discharges ink to a recording material facing an ejection port surface provided with ejection ports to perform recording.
And a carriage for moving the recording head 65 with the. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). Thus, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the area adjacent thereto.

Reference numeral 51 denotes a paper feed unit for inserting a recording material;
Reference numeral 2 denotes a paper feed roller driven by a motor (not shown). With this configuration, the recording material is fed to a position facing the discharge port surface 65 of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as recording proceeds. In the above configuration, when the print head 65 finishes printing and returns to the home position, the cap of the ejection recovery section 64
62 is retracted from the moving path of the recording head 65,
The blade 61 protrudes into the movement path. as a result,
The ejection port 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 6
2 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 position as the position at the time of the wiping described above. As a result, the ejection port surface of the recording head 65 is also wiped during this movement. The above-described movement of the print head to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at a predetermined interval while the print head moves through the printing area for printing to the home position adjacent to the printing area. Then, the wiping is performed with this movement.

FIG. 5 is a view showing an example of an ink cartridge containing ink supplied to the recording head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink storage portion storing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. 44
Is an ink absorber for receiving waste ink. The ink container preferably has a liquid contact surface with ink formed of polyolefin, particularly polyethylene.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, but may be the one in which they are integrated as shown in FIG. It is preferably used. In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage section for storing ink, for example, an ink absorber is stored, and the ink in the ink absorber is transferred from a head section 71 having a plurality of orifices. It is configured to be ejected as ink droplets. It is preferable for the present invention to use polyurethane as the material of the ink absorber. Further, a structure may be used in which the ink storage unit is an ink bag in which a spring or the like is provided inside without using the ink absorber. 72
Is an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. This recording unit 70 is used in place of the recording head 65 shown in FIG.
6 is detachable.

(Ink Jet Recording Apparatus Utilizing Mechanical Energy) Next, as a preferable example of an ink jet recording apparatus utilizing mechanical energy, a nozzle forming substrate having a plurality of nozzles and a nozzle are disposed to face the nozzles. An on-demand ink jet recording head that includes a pressure generating element made of a piezoelectric material and a conductive material, and ink that fills the periphery of the pressure generating element, displaces the pressure generating element by an applied voltage, and discharges small droplets of ink from a nozzle. Can be mentioned. FIG. 7 shows an example of a configuration of a recording head which is a main part of the recording apparatus.

The head includes an ink flow path 80 communicating with an ink chamber (not shown), an orifice plate 81 for discharging ink droplets of a desired volume, a vibration plate 82 for directly applying pressure to ink, and a It comprises a piezoelectric element 83 joined to the diaphragm 82 and displaced by an electric signal, and a substrate 84 for pointing and fixing the orifice plate 81, the diaphragm 82 and the like.

In FIG. 7, the ink flow path 80 is formed of a photosensitive resin or the like, and the orifice plate 81 has a discharge port 85 formed by electroforming or pressing a metal such as stainless steel or nickel. The plate 82 is formed of a metal film such as stainless steel, nickel, titanium or the like and a high elastic resin film, and the piezoelectric element 83 is formed of a dielectric material such as barium titanate or PZT. The recording head having the above-described configuration applies a pulse-like voltage to the piezoelectric element 83 to generate a strain stress, and the energy thereof deforms the diaphragm bonded to the piezoelectric element 83, and the ink flow path 8
The operation is performed in such a manner that the ink in 0 is vertically pressed and ink droplets (not shown) are discharged from the discharge ports 85 of the orifice plate 81 to perform recording. Such a recording head is used by being incorporated in an ink jet recording apparatus similar to that shown in FIG. The detailed operation of the inkjet recording device
The same operation as described above may be performed.

[0069]

EXAMPLES The present invention will be specifically described below with reference to examples. The “parts” are based on weight unless otherwise specified.

[Preparation of Self-Dispersion Type Pigment Dispersion] (Pigment Dispersion 1: Carbon Black) Surface area of 230 m ² / g
10g of carbon black with DBP oil absorption of 70mL / 100g
And 3.41 g of p-amino-N-benzoic acid were mixed well with 72 g of water, and 1.62 g of nitric acid was added dropwise thereto, followed by stirring at 70 ° C. A few minutes later, a solution of 1.07 g of sodium nitrite dissolved in 5 g of water was added, and the mixture was further stirred for 1 hour. The obtained slurry was filtered with Toyo Filter Paper No. 2 (manufactured by Advantis), and the pigment particles were sufficiently washed with water and dried in an oven at 90 ° C. % Aqueous pigment solution was prepared. By the above method, as represented by the following formula, Pigment Dispersion Liquid 1 in which anionic charged self-dispersible carbon black having a hydrophilic group bonded via a phenyl group on the surface was dispersed.

(Pigment Dispersion 2: Cyan)
Blue TGR "(C.I. manufactured by Dainippon Ink and Chemicals, Inc.)
Pigment Blue 15: 3) and 4.0 g of p-aminobenzenesulfonic acid (manufactured by Kanto Kagaku) were mixed in a beaker immersed in a 70 ° C water bath. A solution prepared by dissolving 1.68 g of sodium nitrite (manufactured by Kanto Kagaku) in 74.32 g of deionized water was quickly poured into the former beaker with stirring to obtain a slurry pigment. PH of hydrochloric acid of the obtained slurry
(Kanto Chemical) adjusted to 2. Then, stir at 70 ° C with magnetic stirrer for 1 hour,
The slurry was dried by the oven of No. 1. The obtained dried product was subjected to Soxhlet extraction with methanol for 10 hours, followed by removal of by-products and re-drying.
To obtain a phthalocyanine pigment surface-modified by the _{^{Na + - C 6 H 4 SO}} 3 by the above method. Further, water was added to this pigment to prepare a pigment dispersion liquid 2 having a pigment concentration of 10% by weight.

[0072] (Pigment Dispersion 3: ^{_{Magenta) C 6 H 4 SO 3 -}} Na
^The quinacridone pigment surface-modified with “ ⁺ ” is replaced with “Fastgen Super Magenta RTS” (C.I. Pigment Red 122 manufactured by Dainippon Ink and Chemicals, Inc.) in place of the above Fastogen Blue TGR. ) Was prepared in the same manner as in Pigment Dispersion Liquid 2. Further, water was added to this pigment to prepare a pigment aqueous solution 3 having a pigment concentration of 10% by weight.

(Pigment Dispersion 4: Carbon Black) 300 g of commercially available acidic carbon black “MA-77” (pH 3.0, manufactured by Mitsubishi Kasei Co., Ltd.) was well mixed in 1000 mL of water, and then added with sodium hypochlorite ( (Effective chlorine concentration 12%) 450 g
The mixture was stirred at 100 to 105 ° C for 10 hours. The obtained slurry was filtered through Toyo Filter Paper No. 2 (manufactured by Advantis), and the pigment particles were sufficiently washed with water. This pigment wet cake with water 3000
The suspension was redispersed in mL, and desalted with a reverse osmosis membrane until the electric conductivity reached 0.2 μS. Further, this pigment dispersion (pH = 8 to 10) was treated with a pigment concentration of 1
Concentrated to 0% by weight. According to the above-mentioned method, a pigment dispersion liquid 4 in which anionic charged self-dispersible carbon black having a hydrophilic —COO 2 ^— group directly bonded was dispersed.

(Pigment Dispersion 5: Magenta) Commercially available organic red pigment Shinkasha Red B RT-790D (CI Pigment)
Violet19: CIBA-GEIGY (trade name) 300g Water 1
After mixing well to 000 mL, the mixture was dispersed in a horizontal sand mill for 5 hours. 450 g of sodium hypochlorite (effective chlorine concentration 12%) was added dropwise to the dispersion, and the mixture was stirred at 50 to 60 ° C for 15 hours.
The obtained slurry was filtered through filter paper No. 2 (manufactured by Toyo Advantic) and washed with water until pigment particles leaked. The pigment wet cake was redispersed in 3000 mL of water, and the filtrate was desalted to a conductivity of 70 μS using a reverse osmosis membrane. Further, the pigment dispersion adjusted to pH = 9.5 with aqueous ammonia was concentrated to a pigment concentration of 10% by weight. According to the above-mentioned method, a pigment dispersion liquid 5 in which an anionic charged self-dispersible magenta pigment having a hydrophilic —COO 2 ^— group directly bonded was dispersed.

(Pigment Dispersion 6: Cyan) 300 g of a commercially available blue pigment Cyanine Blue BNRS (CI Pigment Blue 15: trade name, manufactured by Toyo Ink Co., Ltd.) was thoroughly mixed in 1000 mL of water, and then mixed with a horizontal sand mill for 2 hours. Dispersed. 1000 g of sodium hypochlorite (effective chlorine concentration: 12%) was added dropwise to the dispersion, and the mixture was stirred at 10 to 20 ° C for 12 hours. The obtained slurry was filtered with Toyo Filter Paper No. 2, and washed with water until pigment particles leaked. The pigment wet cake was redispersed in 3000 mL of water, and the filtrate was desalted to a conductivity of 70 μS using a reverse osmosis membrane. Further, this pigment dispersion was concentrated to a pigment concentration of 10% by weight. By the above method, the surface of the hydrophilic -CO
A pigment dispersion liquid 6 in which an anionically charged self-dispersion type cyan pigment to which an O ^- group was directly bonded was dispersed was obtained.

[Preparation of Resin-Dispersed Pigment Dispersion] (Pigment Dispersion 7: Magenta) Pigment Red 122 20 parts Styrene-maleic acid copolymer (weight average molecular weight = 10,000) 4.0 parts Triethanolamine 3.0 parts Diethylene glycol 1.0 part Water After heating the components other than the pigment to 70 ° C. in a water bath to prepare a resin solution, the pigment was added by a jet mill and dispersed for 2 hours. (Glass beads (1 mm diameter)
5 times the amount). Further, the obtained dispersion is centrifuged (12,
(000 RPM, 15 minutes) to remove coarse particles, and water was added to obtain a pigment dispersion 7 having a pigment concentration of 10 wt%.

(Pigment Dispersion 8: Cyan) Pigment Red
In place of 122, 20 parts of Pigment Blue 15: 3 were prepared, and the same dispersion treatment as in the preparation of the above magenta dispersion was performed to prepare a cyan dispersion having a pigment concentration by weight of 10%. This is referred to as a pigment dispersion liquid 8.

(Pigment Dispersion 9: Yellow) In place of Pigment Red 122, 20 parts of Pigment Yellow 128 were prepared, and subjected to the same dispersion treatment as in the preparation of the above magenta dispersion to obtain a yellow dispersion having a pigment weight concentration of 10%. A liquid was prepared. This is designated as Pigment Dispersion Liquid 9.

(Pigment Dispersion 10: Carbon Black) In place of Pigment Red 122, 20 parts of Monac 1000, a carbon black manufactured by Cabot Corporation, was prepared and subjected to the same dispersion treatment as in the preparation of the above magenta dispersion to obtain a pigment weight. A black dispersion having a concentration of 10% was prepared. This is designated as Pigment Dispersion 10.

Example 1 (Composition of Black Pigment Ink) Pigment Dispersion 1 30 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH (Acetylene glycol EO adduct manufactured by Kawaken Fine Chemical) 0.1 part Water 51.9 parts The above components were mixed, sufficiently stirred and dissolved, and then filtered under pressure through a 2.5 μm pore size microfilter (manufactured by Fuji Film) to prepare a black pigment ink having a pigment concentration of 3%.

(Cyan Pigment Ink Composition) Pigment Dispersion 2 30 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH 0.1 parts Water 75.9 parts Pressure filtration was performed using a 2.5 μm micro filter (manufactured by Fuji Film) to prepare a cyan pigment ink having a pigment concentration of 0.6%.

(Composition of magenta pigment ink) Pigment dispersion 3 8 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH 0.1 parts Water 75.9 parts The above components are mixed, sufficiently stirred and dissolved, and the pore size is reduced. The solution was filtered under pressure through a 2.5 μm micro filter (manufactured by Fuji Film) to prepare a magenta pigment ink having a pigment concentration of 0.8%.

(Composition of Dye Yellow Ink) CI Direct Yellow 86 1.5 parts Triethylene glycol 10 parts Acetylenol EH 1 part Deionized water 87.5 parts After mixing and dissolving the above components, the pore size was 0.22 μm.
Under pressure with a membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.) to obtain a yellow ink having a dye concentration of 1.5%.

(Composition of dye magenta ink) CI Acid Red 289 2.5 parts Triethylene glycol 10 parts Acetylenol EH 1 part Deionized water 86.5 parts After mixing and dissolving the above components, the pore size was 0.22 μm.
Under pressure through a membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.) to obtain a magenta ink having a dye concentration of 2.5%.

(Composition of Dye Cyan Ink) CI Direct Blue 199 3.5 parts Triethylene glycol 10 parts Acetylenol EH 1 part Deionized water 85.5 parts After mixing and dissolving the above components, a membrane filter having a pore size of 0.22 μm (Product name: Fluoropore filter,
Pressure filtration was performed using Sumitomo Electric Industries, Ltd.) to obtain a cyan ink having a dye concentration of 3.5%.

The above six ink sets were subjected to a storage test at 60 ° C. for 3 months, and the viscosity and particle size (measured using “UPA-150” (laser Doppler system particle size distribution analyzer manufactured by Nikkiso Co., Ltd.)). As a result, there was no change from before storage.

Example 2 In the ink set of Example 1, the magenta pigment concentration was 1.2%, and the cyan pigment concentration was 1.2%.
The ink set of 1.0% is defined as an ink set of Example 2.

When a storage test was conducted in the same manner as in Example 1 of the ink set, there was no change in viscosity and particle diameter as compared with before storage.

Example 3 (Composition of Black Pigment Ink) Pigment Dispersion 4 30 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH 0.1 parts Water 41.9 parts The above components were mixed and thoroughly stirred. After dissolution, the solution was filtered under pressure through a 2.5 μm pore size micro filter (manufactured by Fuji Film) to prepare a black pigment ink having a pigment concentration of 3%.

(Composition of magenta pigment ink) Pigment dispersion 5 8 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH 0.1 parts Water 73.9 parts The above components are mixed, sufficiently stirred and dissolved, and the pore size is reduced. The solution was filtered under pressure through a 2.5 μm microfilter (manufactured by Fuji Film) to prepare a magenta pigment ink having a pigment concentration of 0.8%.

(Preparation of Cyan Pigment Ink) Pigment dispersion 6 6 parts Trimethylolpropane 6 parts Glycerin 6 parts Diethylene glycol 6 parts Acetylenol EH 0.1 parts Water 75.9 parts The above components are mixed, sufficiently stirred and dissolved, and the pore size is reduced. Pressure filtration was performed using a 2.5 μm microfilter (manufactured by Fuji Film) to prepare a cyan pigment ink having a pigment concentration of 0.6%.

An ink set comprising the above three kinds of pigment inks and the three kinds of dye inks used in Example 1 was used in Example 3.
Of ink set.

When a storage test was conducted in the same manner as in Example 1 of the ink set, the viscosity and the particle size were not changed as compared with those before storage.

[Comparative Example 1] (Composition of dyed light magenta ink) CI Acid Red 289 0.8 parts Triethylene glycol 10 parts Acetylenol EH 1 part Ion-exchanged water 88.2 parts Is 0.22
Pressure filtration was performed using a μm membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.) to obtain a magenta ink having a dye concentration of 0.8%.

(Composition of Dye Light Cyan Ink) CI Direct Blue 199 0.8 parts Triethylene glycol 10 parts Acetylenol EH 1 part Deionized water 88.2 parts After mixing and dissolving the above components, the pore size was 0.22.
Pressure filtration was performed using a μm membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.) to obtain a cyan ink having a dye concentration of 0.8%.

(Composition of Dye Black Ink) CI Food Black 2 3 parts Triethylene glycol 10 parts Acetylenol EH 1 part Ion-exchanged water 86 parts After the above components were mixed and dissolved, the pore size was 0.22.
Pressure filtration was performed using a μm membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.) to obtain a black ink having a dye concentration of 3%.

An ink set consisting of the three dye inks and the three dye inks described in Example 1 is referred to as an ink set of Comparative Example 1.

[Comparative Example 2] (Preparation of ink) Pigment dispersion 7 8 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Ion-exchanged water 66.9 parts The above components were mixed and thoroughly stirred. After dissolution, the solution was filtered under pressure with a micro filter having a pore size of 2.5 μm (manufactured by Fuji Film) to prepare a magenta pigment ink having a pigment concentration of 0.8%.

(Preparation of ink) Pigment dispersion liquid 8 6 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Deionized water 68.9 parts The above components were mixed, sufficiently stirred and dissolved. Pressure filtration was performed using a 2.5 μm pore size micro filter (manufactured by Fuji Film) to prepare a cyan pigment ink having a pigment concentration of 0.6%.

An ink set consisting of two kinds of the pigment light inks adjusted as described above, three kinds of the dye deep inks and the pigment black ink described in Example 1 is used as an ink set of Comparative Example 2.

When a storage test was conducted in the same manner as in Example 1 of the ink set, the viscosity and particle diameter of the inks comprising the pigment dispersions 7 and 8 both increased as compared to before storage.

[Comparative Example 3] (Preparation of ink) Pigment dispersion 7 50 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Ion-exchanged water 24.9 parts The above components were mixed and sufficiently stirred. After dissolution, the solution was filtered under pressure through a micro filter having a pore size of 2.5 μm (manufactured by Fuji Film) to prepare a magenta pigment ink having a pigment concentration of 5%.

(Preparation of Ink) Pigment Dispersion 8 40 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Deionized water 34.9 parts The above components were mixed, sufficiently stirred and dissolved. Pressure filtration was performed using a 2.5 μm pore size microfilter (manufactured by Fuji Film Co., Ltd.) to prepare a cyan pigment ink having a pigment concentration of 4%.

(Preparation of ink) Pigment dispersion 9 40 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Ion-exchanged water 34.9 parts The above components were mixed, sufficiently stirred and dissolved. Pressure filtration was performed using a 2.5 μm pore size microfilter (manufactured by Fuji Film) to prepare a yellow pigment ink having a pigment concentration of 4%.

(Preparation of ink) Pigment dispersion 10 40 parts Glycerin 10 parts Diethylene glycol 10 parts Polyethylene glycol # 400 5 parts Acetylenol EH 0.1 parts Ion-exchanged water 34.9 parts The above components were mixed, sufficiently stirred and dissolved. The mixture was filtered under pressure with a 2.5 μm pore size microfilter (manufactured by Fuji Film) to prepare a black pigment ink having a pigment concentration of 4%.

An ink set including the four kinds of pigment dark inks adjusted as described above and the two kinds of light pigment inks shown in Comparative Example 2 is referred to as an ink set of Comparative Example 3.

A storage test was conducted in the same manner as in Example 1 of the above ink set.
Both have increased compared to before storage.

An ink-jet color recording apparatus having a plurality of on-demand recording heads for applying the thermal energy according to the recording signal to the ink sets of the examples and comparative examples obtained as described above to eject ink. An image was formed by applying the above method, and color tone, water fastness, light fastness and ozone fastness were tested.

The evaluation of the recorded image was performed by the following method.

1. Color Tone Using the above ink set, copy paper manufactured by Canon
(PB-Paper), Canon inkjet coated paper
(HR-101) and a glossy film made by Canon (HG-201), a halftone image was formed, and the color tone of the image by the other ink set with respect to the image by the ink set of Comparative Example 1 was 5 for each paper. It was evaluated by a human sensory test.

2. Light fastness: Using the above ink set,
After forming a halftone image on Canon copy paper (PB-Paper), Canon inkjet coated paper (HR-101) and Canon glossy film (HG-201), leave it for 24 hours and then use an atlas fade meter With illumination 0.3
The test was performed under the conditions of 9 W / m ² , a relative humidity of 70%, a temperature of 50 ° C., and an exposure time of 30 hours. The difference in image chromaticity before and after the test was evaluated for light resistance by a sensory test by five persons.

3. Ozone resistance: Using the above-mentioned ink set, intermediate between Canon copy paper (PB-Paper), Canon inkjet coated paper (HR-101) and Canon glossy film (HG-201). After forming a tone image 24
After leaving for a period of time, a test was performed with an ozone fade meter at an ozone concentration of 3 ppm and an exposure time of 2 hours. The difference in image chromaticity before and after the test, which was the same as the light resistance, was evaluated by a sensory test by five persons.

Evaluation results of color tone of recorded images and light fastness,
The ozone resistance test results are described below.

1. Color Tone The printing with the ink set of Examples 1 and 3 did not show much inferiority to the printing with the ink set of Comparative Example 1 for both plain paper and special paper. When it did, it showed the same color tone as Comparative Example 1. In the printing using the ink set of Example 2, the color tone was better when printed on special paper than when printed on plain paper. However, the color tone was not so good as in Examples 1 and 3, and was dull. It was a color tone. In the printing using the ink set of Comparative Example 2, the color tone of both plain paper and special paper was not good as compared with Examples 1, 2, and 3. In the printing using the ink set of Comparative Example 3, both the plain paper and the special paper were inferior in color tone as compared with the ink sets of the other Comparative Examples and Examples.

2. Lightfastness In printing with the ink sets of Examples 1, 2, and 3 and Comparative Examples 2 and 3, no change was observed in the images of the plain paper and the special paper before and after the test. However, in the printing using the ink set according to Comparative Example 1, the discoloration of both plain paper and special paper was intense.

3. Ozone resistance In printing with the ink sets of Examples 1, 2, and 3 and Comparative Examples 2 and 3, no change was observed in the images of the plain paper and the special paper before and after the test. However, in the printing with the ink set according to Comparative Example 1, the discoloration was a little on plain paper, and the discoloration was severe on the special paper.

[0117]

As described above, according to the present invention,
By using dye ink for dark ink and self-dispersed pigment ink for light ink, it is possible to form images with high robustness while maintaining the color tone of photographic images compared to the case of dark and light ink set using only dye ink. Can be done.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating an example of a head of an inkjet recording apparatus.

FIG. 2 is a cross-sectional view illustrating an example of a head of the inkjet recording apparatus.

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

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

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

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

FIG. 7 is a schematic cross-sectional view illustrating another configuration example of the inkjet recording head.

[Explanation of symbols]

 13 Head 14 Ink groove 15 Heating head 16 Protective film 17-1, 17-2 Electrode 18 Heating resistor layer 19 Heat storage layer 20 Substrate 21 Ink 22 Discharge orifice (micro hole) 23 Meniscus 24 Ink droplet 25 Recording material 26 Multi Groove 27 Glass plate 28 Heating head 40 Ink bag 42 Plug 44 Ink absorber 45 Ink cartridge 51 Paper feed unit 52 Paper feed roller 53 Discharge roller 61 Blade 62 Cap 63 Ink absorber 64 Discharge recovery unit 65 Recording head 66 Carriage 67 Guide Shaft 68 Motor 69 Belt 70 Recording unit 71 Head 72 Air communication port 80 Ink flow path 81 Orifice plate 82 Vibration plate 83 Piezoelectric element 84 Substrate 85 Discharge port

Continuation of the front page (72) Inventor Shoji Koike 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 EA13 ED07 FA03 FC01 FC02 2H086 BA02 BA21 BA31 BA34 BA55 BA62 4J039 BE01 BE02 EA15 EA16 EA17 EA19 EA21 EA34 EA35 FA02 FA07 GA24

Claims (14)

[Claims] In a color ink set for recording an image on a recording material by an ink jet recording method, at least one color ink is composed of two or more types of inks having different color material densities, and an ink having a low color material density is provided. Using pigment for
An ink characterized in that the pigment is a self-dispersed pigment having at least one hydrophilic group bonded to the surface thereof directly or via another atomic group, and a dye is used in an ink having a high coloring material concentration. set. 2. The hydrophilic group is at least one selected from the following hydrophilic groups, and the other atomic group has an alkyl group having 1 to 12 carbon atoms, a substituent or is unsubstituted. The ink set according to claim 1, wherein the phenyl group is a substituted or unsubstituted naphthyl group.
(However, M in the formula represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, and R has 1 to 1 carbon atoms.
12 represents an alkyl group, a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group. -COOM, -SO ₃ M, -SO ₂ NH ₂ , -PO ₃ HM, -PO ₃ M ₂ , -SO ₂ NHCOR, -NH ₃ ⁺ , -NR ₃ ⁺ , 3. The self-dispersing pigment according to claim 1, wherein the hydrophilic group is -COOM,-
SO ₃ M, -SO ₂ NH ₂ , -PO ₃ HM, -PO ₃ M ₂ , -SO
₂ NHCOR is at least one selected from the group consisting of an alkyl group having 1 to 12 carbon atoms,
The ink set according to claim 1, wherein the ink set is a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group. Wherein M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, and R represents an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group or a substituted or unsubstituted phenyl group. Represents a substituted naphthyl group. 4. A dye concentration used for an ink having a high color material concentration, wherein the pigment concentration is at least 1% by weight, which is composed of at least yellow, magenta, cyan, and black, and is used for an ink having a low color material concentration. Is 1% by weight or more. 5. An ink jet recording method in which energy is given to an ink to fly the ink and apply it to a recording material to perform recording, wherein the ink is used as the ink.
An inkjet recording method using the ink set described in any one of the above. 6. The ink jet recording method according to claim 5, wherein said recording material is plain paper. 7. The ink jet recording method according to claim 5, wherein the recording material is a coating support containing at least a hydrophilic polymer and / or an inorganic porous material. 8. The ink jet recording method according to claim 5, wherein said energy is heat energy. 9. The ink jet recording method according to claim 5, wherein the energy is mechanical energy. 10. A recording unit comprising an ink containing section containing ink and a head section for ejecting the ink, wherein the ink is the ink set according to any one of claims 1 to 4. And a recording unit. 11. An ink cartridge provided with an ink storage section for storing ink, wherein the ink is an ink cartridge.
5. An ink cartridge, which is the ink set according to any one of 4. 12. An ink jet recording apparatus comprising: a recording unit having an ink containing section for containing ink and a head section for ejecting the ink as ink droplets by the action of thermal energy.
5. An ink jet recording apparatus, comprising the ink set according to any one of 4. 13. An ink jet recording apparatus comprising: an ink cartridge having an ink containing section containing ink; and a head section for ejecting the ink by the action of thermal energy. An ink jet recording apparatus comprising the ink set according to any one of the above. 14. The ink jet and recording apparatus according to claim 13, further comprising an ink supply unit that supplies the ink contained in the ink cartridge to the recording head.