JP2005162981A - Ink set, ink cartridge, recording device and method for recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a recorded material having a good ink fixation and improved with gloss change. <P>SOLUTION: This ink set contains a deep-colored ink composition and pale-colored ink composition having the same color each other but different color concentrations, and both of the deep-colored ink composition and pale-colored ink composition contain at least a pigment as a coloring agent, a resin as a dispersing agent and a resin emulsion, and the resin emulsion in the deep-colored ink composition is a different kind from the resin emulsion in the pale-colored ink composition. By using the ink set, recording is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink set, an ink cartridge, a recording apparatus, and a recording method, and more particularly to an ink set that can provide a recorded matter with good ink fixability and improved gloss change.

The ink jet recording method is a printing method in which droplets of an ink composition are ejected and attached to a recording medium such as paper to perform recording. This method has a feature that a high-resolution and clear image can be printed at high speed while using a relatively inexpensive apparatus.
As an ink set used for such an ink jet recording method, an ink set including each ink composition of cyan (C), magenta (M), yellow (Y), and one added with black (K), etc. There is.

  In recent years, in order to obtain a higher image quality, an ink set including dark and light inks having the same color but different color densities has been developed. For example, K, C, M, and Y ink compositions are used as dark inks, and light black (Lk), light cyan (Lc), light magenta (Lm), and light yellow (Ly) are used as light inks. Some are provided with each color ink composition.

  By using this ink set with light and dark inks and changing the amount of colorant (duty level) to land per unit area of the recording medium, the graininess due to the ink dots is reduced, and silver salt photography High-quality color images comparable to those can be output.

  However, an ink set including such dark and light inks has a problem in that the recording image quality is deteriorated because the printing characteristics and the fixing characteristics on the recording medium are different between the dark ink composition and the light ink composition. was there.

  In addition, with this improved recording image quality, for ink sets with dark and light inks, when the recorded material is touched with a finger or the like, even if the pigment is not removed, the finger marks remain on the recorded material, color traces occur, There has been no report of an improvement in the phenomenon of gloss change such as a change in gloss.

  For example, Japanese Patent Laid-Open No. 2000-351931 discloses an ink composition that includes a colorant and a resin emulsion, and these have the same polarity of charge (Patent Document 1). (Patent Document 2) and JP-A-8-283636 discloses an ink containing a low MFT resin emulsion and a high TG resin emulsion (Patent Document 2). Patent Document 3) and Japanese Patent Application Laid-Open No. 2001-177996 disclose dark and light inks each having a specific surface tension (Patent Document 4), and International Publication No. 01/48100 is a resin having a specific content. And a dark and light ink each containing a pigment (Patent Document 5), Japanese Patent Application Laid-Open No. 10-245511 discloses an ionic group on the surface. JP-A-2000-7961 discloses an ink composition that introduces an ink composition that has a TG of 10 ° C. to 60 ° C. and a film-forming resin content of less than 5% by weight. Although a composition is disclosed (Patent Document 7), an ink set that can provide a recorded matter in which gloss change, glossiness, and ink fixing property (rubbing resistance) are all improved is not provided.

JP 2000-351931 A JP 2002-30235 A JP-A-8-283636 Japanese Patent Laid-Open No. 2001-179956 International Publication No. 01/48100 Pamphlet Japanese Patent Laid-Open No. 10-245511 JP 2000-7961 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink set, an ink cartridge, a recording apparatus, and a recording method that can provide a recorded matter with good ink fixability (rubbing resistance) and improved gloss change. It is in.

  The inventors of the present invention have a large amount of pigment deposited on the recording medium, and the pigment is piled up, so that a gloss change often occurs when rubbing with a finger or the like, and a light ink is a pigment dispersant. Focusing on the problem that effective fixability is often difficult to obtain due to its low content, as a result of intensive studies, it contains a dark ink composition and a light ink composition that have the same color but different color densities. In the ink set, each of the dark ink composition and the light ink composition includes at least a pigment as a colorant, a resin as a dispersant, and a resin emulsion, and the resin emulsion in the dark ink composition includes: By using an ink set different from the resin emulsion in the light ink composition, a recorded matter with good ink fixability and improved gloss change was obtained. It was finding the Rukoto.

  That is, the ink set of the present invention is an ink set containing a dark ink composition and a light ink composition having the same color but different color densities, and the dark ink composition and the light ink composition Each includes at least a pigment as a colorant, a resin as a dispersant, and a resin emulsion, the resin emulsion in the dark ink composition is a polyester emulsion, and the resin emulsion in the light ink composition is alkali-soluble. It is an emulsion.

  With the above configuration, the gloss change of dark ink is improved and the fixability is further improved, the fixability of light ink is improved and the gloss change is further improved. A remarkable effect that a good image quality can be obtained is obtained.

  Therefore, by using the ink set of the present invention, it is possible to obtain a recorded matter in which darkness and lightness inks are improved in both fixability and gloss change.

  The alkali-soluble emulsion is preferably an acrylic resin emulsion.

  The weight average molecular weight (Mw) of the alkali-soluble resin of the alkali-soluble emulsion is preferably 8000 or more and 20000 or less.

  The content of the resin emulsion (in terms of solid content) is 0.5% by weight or more and 5.0% by weight or less in the dark ink composition, and 0.1% by weight or more in the light ink composition. It is preferably 0% by weight or less.

  Further, the ink set of the present invention includes at least a cyan ink composition and a magenta ink composition as the dark ink composition, and includes at least a light cyan ink composition and a light magenta ink composition as the light ink composition, The resin emulsion in the cyan ink composition is a polyester emulsion, the resin emulsion in the light cyan ink composition is an alkali-soluble emulsion, the resin emulsion in the magenta ink composition is a polyester emulsion, and the light emulsion The resin emulsion in the magenta ink composition is an alkali-soluble emulsion.

  The ink set is used for inkjet recording.

  The ink cartridge of the present invention contains the ink set.

  An ink jet recording apparatus of the present invention includes the above ink set.

  The recording method of the present invention performs recording by using the above ink set and attaching each ink composition to a recording medium.

  According to the ink set, the ink cartridge, the recording apparatus, and the recording method of the present invention, it is possible to obtain a recorded matter with improved gloss change, glossiness, and ink fixing property.

  Hereinafter, preferred embodiments of the ink set of the present invention will be described, but it goes without saying that the present invention is not limited thereto.

  The ink set of the present invention is an ink set containing a dark ink composition and a light ink composition that are the same color but have different color densities, and which are either the dark ink composition or the light ink composition At least a pigment as a colorant, a resin as a dispersant, and a resin emulsion. The resin emulsion in the dark ink composition is a polyester emulsion, and the resin emulsion in the light ink composition is an alkali-soluble emulsion. It is characterized by being.

  Here, “same color but different color density” means that the same type of colorant is used, and the concentration (weight ratio) of the colorant in each of the dark and light ink compositions is different. It means that.

  In the ink set of the present invention, each of the dark ink composition and the light ink composition includes at least a pigment as a colorant, a resin as a dispersant, and a resin emulsion. The resin emulsion in the dark ink composition is different from the resin emulsion in the light ink composition.

  The ink set of the present invention may contain one pair of dark and light inks having the same color but different color densities, or may contain two or more pairs. When two or more pairs are contained, it means that the dark and light ink compositions forming each pair contain different types of resin emulsions.

  By configuring as described above, it is possible to obtain a recorded matter with good ink fixability and improved gloss change. In other words, the characteristics of the dark ink and the light ink are combined to realize an extremely good image quality with improved fixability and gloss change.

  The resin emulsion is preferably formed by colloidal dispersion of a resin in each ink composition. For example, polymer fine particles are preferably added to each ink composition in the form of an emulsion. Alternatively, a resin emulsion can be obtained by dispersion polymerization of a monomer in an aqueous medium in the presence of a surfactant.

  The resin emulsion in the dark ink composition is preferably a polyester emulsion, and the resin emulsion in the light ink composition is preferably an alkali-soluble emulsion. With this configuration, the ink fixing property and gloss change are further improved, and the surface gloss of the recorded matter is also improved.

  As polyester emulsions, Toyobo Co., Ltd. Bironal MD-1400 (polyester resin content: 15% by weight), MD-1480 (polyester resin content: 25% by weight), MD-1500 (polyester resin content: 30) % By weight), MD-1930 (polyester resin content: 31% by weight), MD-1985 (polyester resin content: 27% by weight) and the like are preferably used.

  The alkali-soluble emulsion is preferably an emulsion formed by colloidal dispersion of an acrylic resin in the ink composition.

  As an acrylic resin, an ethylenically unsaturated carboxylic acid monomer and other monomers copolymerizable therewith are polymerized in the presence of an alcoholic hydroxyl group-containing water-soluble polymer compound or a copolymerizable surfactant. The obtained copolymer is preferable.

  Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; ethylenically unsaturated polycarboxylic acids such as itaconic acid, maleic acid, fumaric acid, and butenetricarboxylic acid. Monovalent carboxylic acid monomers; partial ester monomers of ethylenically unsaturated polyvalent carboxylic acids such as monobutyl fumarate, monobutyl maleate and mono-2-hydroxypropyl maleate; many such as maleic anhydride and citraconic anhydride And carboxylic acid anhydrides.

  Other monomers copolymerizable with the ethylenically unsaturated carboxylic acid monomer include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, and chlorostyrene; methyl (meth) acrylate , Ethyl (meth) acrylate, propyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) acrylate, (meth) acrylic acid (Meth) acrylate monomers such as octyl, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and glycidyl (meth) acrylate; cyano group-containing ethylenically unsaturated monomers such as (meth) acrylonitrile An ethylenically unsaturated glycidyl ether monomer such as allyl glycidyl ether; T) Ethylenically unsaturated amide monomers such as acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide; 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene Conjugated diene monomers such as 1,3-pentadiene; carboxylic acid vinyl ester monomers such as vinyl acetate.

  The alcoholic hydroxyl group-containing water-soluble polymer compound is preferably a water-soluble polymer compound containing 5 to 25 alcoholic hydroxyl groups per 1000 molecular weight, such as polyvinyl alcohol and various modified products thereof. Saponified products of copolymers of vinyl acetate and acrylic acid, methacrylic acid or maleic anhydride; cellulose derivatives such as alkyl cellulose, hydroxyalkyl cellulose, alkyl hydroxyalkyl cellulose; alkyl starch, carboxymethyl starch And starch derivatives such as arabic gum, tragacanth gum, polyalkylene glycol and the like.

  The copolymerizable surfactant is a surfactant having one or more polymerizable vinyl groups in the molecule, such as sodium propenyl-2-ethylhexylsulfosuccinate, polyoxyethylene (meth) acrylate. Anionic polymerizable surfactants such as sulfate ester, polyoxyethylene alkylpropenyl ether sulfate ammonium salt, (meth) acrylic acid polyoxyethylene ester phosphate ester; polyoxyethylene alkylbenzene ether (meth) acrylate ester, polyoxyethylene Mention may be made of anionic polymerizable surfactants such as alkyl ether (meth) acrylates.

  The weight average molecular weight (Mw) of the alkali-soluble resin of the alkali-soluble emulsion is preferably 8000 or more and 20000 or less, more preferably 9000, from the viewpoint of further improving the fixability of the ink, gloss change and surface gloss. Above, it is below 10000.

  The acid value of the alkali-soluble resin of the alkali-soluble emulsion is preferably 40 mgKOH / g or less from the viewpoint of further improving the fixability, gloss change and surface gloss of the ink.

  The alkali-soluble resin is adjusted to a pH of 8 to 11 (more preferably a pH of 9 to 10) with an inorganic base such as an alkali metal hydroxide or an alkaline earth metal hydroxide, and then colloid in the ink composition. It is preferable to disperse to form an emulsion.

  The content of the resin emulsion (in terms of solid content) is preferably in the dark ink composition from the viewpoint of further improving the ink fixing property, gloss change and surface glossiness, and maintaining the ink viscosity appropriately. 0.5 wt% or more and 5.0 wt% or less, more preferably 1.0 wt% or more and 3.0 wt% or less, in the light ink composition, preferably 0.1 wt% or more, It is 2.0 weight% or less, More preferably, it is 0.3 weight% or more and 1.0 weight% or less.

  Different types of resin emulsions may be added to the dark and light inks, respectively, or two or more types of resin emulsions may be mixed and added to the dark and light inks. When added in a mixed manner, the total content of these is preferably the above content in the ink composition.

  The weight ratio of pigment to resin emulsion (pigment / resin emulsion) in the dark ink composition is preferably 0.12 to 8.00, and the weight ratio of pigment to resin emulsion in the light ink composition ( The pigment / resin emulsion) is preferably 0.001 or more and 3.00 or less.

  The pigment as the colorant is not particularly limited, and a colorant contained in a normal color ink composition for inkjet recording can be used.

  In the ink set of the present invention, the dark ink composition is a cyan ink composition and / or a magenta ink composition, and the light ink composition is a light cyan ink composition and / or a light magenta ink composition. preferable. That is, it is preferable to use a combination of a cyan ink composition and a light cyan ink composition, a combination of a magenta ink composition and a light magenta ink composition, or both of them as the dark and light ink composition. Further, a combination of a yellow ink composition and a light yellow ink composition, or a combination of a black ink composition and a light black ink composition may be used.

  As a colorant for the cyan ink composition and the light cyan ink composition, a cyan pigment is preferably used. Examples of the cyan pigment include C.I. I. Pigment Blue 15: 3, 15: 4, 60, 1, 2, 3, 16, 22, 15:34 and the like are preferably used. I. Pigment Blue 15: 3 is preferable.

  A magenta pigment is preferably used as the colorant of the magenta ink composition and the light magenta ink composition. Examples of the magenta pigment include C.I. I. Pigment Red 122, 202, 209, 112, 123, 168, 184, 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1 and C.I. I. Pigment Violet 19 or the like is preferably used. I. Pigment Red 122 and 202 are preferred.

  As a colorant for the yellow ink composition and the light yellow ink composition, a yellow pigment is preferably used. Examples of the yellow pigment include C.I. I. Pigment yellow 74, 81, 83, 93, 109, 110, 120, 128, 138, 139, 150, 151, 154, 155, 173, 180, 185, 195 and the like.

  In addition to the above, the ink set of the present invention includes a black ink composition, a red ink composition, a violet ink composition, a blue ink composition, a light black ink composition, a green ink composition, a dark yellow ink composition, and an orange ink. A composition or the like may be provided.

A black pigment is preferably used as the colorant of the black ink composition (K). Examples of the black ink pigment include carbon black.
In the ink set, when the same color and a large amount of colorant are defined as a dark ink composition and a small colorant as a light ink composition, the content of the colorant is preferably 1. It is 5% by weight or more and 10% by weight or less, more preferably 2.0% by weight or more and 7.0% by weight or less. On the other hand, in the light ink composition, the content of the colorant is preferably 0.01% by weight or more and 2.0% by weight or less, more preferably 0.5% by weight or more and 1.5% by weight. It is as follows. The content of the colorant is appropriately adjusted according to the type of ink composition such as a dark and light ink composition.

  Each ink composition of the present invention contains a pigment dispersion obtained by dispersing a pigment as a colorant in an aqueous medium with a resin as a dispersant.

  Resin as a dispersing agent is not specifically limited, The resin contained in the normal color ink composition for inkjet recording can be used.

  Examples of the resin used as the dispersant include methacrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, methacryl-styrene resins, butadiene resins, styrene resins, crosslinked methacrylic resins, Examples thereof include a crosslinked styrene resin, a benzoguanamine resin, a phenol resin, a silicone resin, and an epoxy resin.

  In the case of the dark ink composition, the amount of the dispersant resin added is preferably 10 parts by weight or more and 100 parts by weight or less, more preferably 20 parts by weight or more, with respect to 100 parts by weight of the pigment in terms of solid content. 80 parts by weight or less, and in the case of the light ink composition, preferably 10 parts by weight or more and 100 parts by weight or less, more preferably 20 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of the pigment in terms of solid content. Or less.

  As the aqueous medium, a solvent generally used in an aqueous ink composition for ink jet recording is used, and specific examples include water, a water-soluble organic solvent, or a mixture thereof.

  When water is used as the aqueous medium, water is added as the remaining amount of each component in each ink composition.

  When a water-soluble organic solvent is used as the aqueous medium, both the low-boiling organic solvent and the high-boiling organic solvent are preferably used as the water-soluble organic solvent. Preferable examples of the low boiling point organic solvent include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, iso-butanol, n-pentanol and the like. A monohydric alcohol is particularly preferable. These low boiling point organic solvents are preferable because they have the effect of shortening the drying time of the ink composition. Preferred examples of the high-boiling organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, Polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol Alkyl ethers of polyhydric alcohols such as ethylene glycol monobutyl ether S, urea, 2-pyrrolidone, N- methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and triethanolamine.

  Each ink composition of the present invention may further contain any one of an acetylene glycol compound, an acetylene alcohol compound, and a polysiloxane compound as a surfactant.

  Thereby, while maintaining the effect of the present invention that improves the fixability and gloss change, it is possible to enhance the ejection stability of the ink composition.

  The surfactant content in each ink composition is preferably 0.1% by weight or more and 3.0% by weight or less, more preferably 0.1% by weight or more and 1.0% by weight or less. .

  As acetylene glycol compounds, Olphine E1010, STG, Y (all trade names, manufactured by Nissin Chemical Co., Ltd.), Surfynol 82, 104, 440, 465, 485 (all trade names, manufactured by Air Products And Chemicals Inc.). ) Etc. can be used.

  Examples of acetylene alcohol compounds include 3,5-dimethyl-1-hexyne-3ol, 2,4-dimethyl-5-hexyne-3-ol, Surfynol 61 (trade name, manufactured by Air Products And Chemicals Inc.) and the like. Can be used.

  As the polysiloxane compound, a compound represented by the following general formula (1) can be used.

  In the above formula, R1 to R7 independently represent a C1-6 alkyl group, preferably a methyl group, and j, k, and g independently represent an integer of 1 or more, preferably 1 to 5, more preferably Is 1 to 4, more preferably 1 or 2. EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. p and q represent an integer of 0 or more, and preferably 1 to 5, provided that p + q represents an integer of 1 or more, and preferably 2 to 4. The order of EO and PO is not limited in [], and may be random or block.

According to a preferred embodiment of the present invention, the compound of formula (I) preferably satisfies j = k = g = 1 to 3, more preferably 1 or 2.
According to another preferred embodiment of the present invention, as the compound of formula (I), R1 to R7 all represent a methyl group, j = k = g = 1, and p is an integer of 1 or more, preferably It is preferably 1 to 5 and q represents 0.
The compounds represented by the general formula (1) are commercially available and can be used. For example, BYK-345, BYK-346, BYK-347, BYK-348, etc., are available from BYK Japan Japan Co., Ltd.

  Each ink composition according to a preferred embodiment of the present invention further contains a tertiary amine as a pH adjuster. Examples of the tertiary amine include trimethylamine, triethylamine, triethanolamine, dimethylethanolamine, diethylethanolamine, triisopropenolamine, butyldiethanolamine and the like. These may be used alone or in combination. The amount of these tertiary amines added is preferably 0.1% by weight or more and 10% by weight or less, more preferably 0.5% by weight or more and 5% by weight or less in each ink composition.

  Each ink composition may further contain an auxiliary agent. Examples of such auxiliaries include chelating agents, preservatives, rust inhibitors, antioxidants, ultraviolet absorbers, oxygen absorbers, and abrasion resistance improvers.

  The ink cartridge of the present invention contains any of the ink sets described above.

  Furthermore, the ink jet recording method of the present invention will be described. In the ink jet recording method of the present invention, recording is performed by attaching each ink composition to a recording medium using the above-described ink set.

  By using these recording methods, it is possible to obtain a recorded matter with good ink fixability and improved gloss change.

<Example>
EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these examples.

(Ink adjustment)
An ink set including the following ink compositions was prepared. In the following, BYK-348 is a polysiloxane-based surfactant manufactured by Big Chemie Japan.

  The resin emulsion in the dark ink composition is 27% aq of a polyester emulsion; Bironal MD-1985 (trade name of Toyobo Co., Ltd.).

  The alkali-soluble emulsion in the light ink composition was prepared as follows.

  Stir and mix 55 parts of ethyl acrylate, 37 parts of methyl acrylate, 6 parts of methacrylic acid, 3 parts of octyl thioglycolate as molecular weight regulator, 2.5 parts of polyvinyl alcohol and 280 parts of ion-exchanged water, The dispersion was adjusted.

  Next, 130 parts of ion-exchanged water and 2 parts of potassium persulfate were charged into a reactor equipped with a stirrer, the temperature was raised to 80 ° C., and the dispersion of the monomer mixture was continuously added over 4 hours for polymerization. After completion of the continuous addition, the reaction was performed at 80 ° C. for 30 minutes.

  Next, 10% aqueous sodium hydroxide solution in an amount corresponding to the charged methacrylic acid and an equimolar amount of sodium hydroxide was added to the reactor, followed by heat treatment at 80 ° C. for 1 hour, and then an appropriate amount of ion-exchanged water was added to form a solid. A resin having a partial concentration of 15% was obtained. The acid value of the resin was 40 mgKOH / g and pH was 9.2. About the resin in the obtained alkali-soluble emulsion, Mw is 11000, glass transition temperature (measured in accordance with JIS K6900) is 25 ° C., average particle size is 50 nm or less, minimum film-forming temperature is 15 ° C., and turbidity is (Measured at a cell width of 10 mm with WATER-ANALYZER2000 manufactured by Color Industrial Co., Ltd.) was 30 g / L or less.

(Ink set A)
[Cyan ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PB15: 3) 4.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.2% by weight
Glycerin 19.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light cyan ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 3.33% by weight
Pigment (PB15: 3) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.19% by weight
Glycerin 25.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Magenta ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PR122) 6.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.5% by weight
Glycerin 16.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.4% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light magenta ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 3.33% by weight
Pigment (PR122) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.24% by weight
Glycerin 25.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Yellow ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PY74) 5.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.3% by weight
Glycerin 18.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

(Ink set B)
[Cyan ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 13.33% by weight
Pigment (PB15: 3) 4.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.2% by weight
Glycerin 17.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light cyan ink composition]
Polyester emulsion (solid content 0.5%) 1.85% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PB15: 3) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.19% by weight
Glycerin 27.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Magenta ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 13.33% by weight
Pigment (PR122) 6.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.5% by weight
Glycerin 12.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.4% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light magenta ink composition]
Polyester emulsion (solid content 0.5%) 1.85% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PR122) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.24% by weight
Glycerin 27.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Yellow ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 13.33% by weight
Pigment (PY74) 5.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.3% by weight
Glycerin 15.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

(Ink set C)
[Cyan ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PB15: 3) 4.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.2% by weight
Glycerin 19.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light cyan ink composition]
Pigment (PB15: 3) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.19% by weight
Glycerin 30.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Magenta ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PR122) 6.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.5% by weight
Glycerin 16.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.4% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light magenta ink composition]
Pigment (PR122) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.24% by weight
Glycerin 30.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Yellow ink composition]
Polyester emulsion (solid content 2%) 7.41% by weight
(Toyobo: Bironal MD1985 27% aq.)
Pigment (PY74) 5.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.3% by weight
Glycerin 18.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

(Ink set D)
[Cyan ink composition]
Pigment (PB15: 3) 4.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.2% by weight
Glycerin 21.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light cyan ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 3.33% by weight
Pigment (PB15: 3) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.19% by weight
Glycerin 25.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Magenta ink composition]
Pigment (PR122) 6.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.5% by weight
Glycerin 17.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.4% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light magenta ink composition]
Alkali-soluble emulsion (15% aq. Solid content 0.5%) 3.33% by weight
Pigment (PR122) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.24% by weight
Glycerin 25.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Yellow ink composition]
Pigment (PY74) 5.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.3% by weight
Glycerin 20.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

(Ink set E)
[Cyan ink composition]
Pigment (PB15: 3) 4.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.2% by weight
Glycerin 21.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light cyan ink composition]
Pigment (PB15: 3) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.19% by weight
Glycerin 30.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Magenta ink composition]
Pigment (PR122) 6.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.5% by weight
Glycerin 17.0% by weight
1,2-hexanediol 4.0% by weight
BYK-348 0.4% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Light magenta ink composition]
Pigment (PR122) 1.0% by weight
Dispersant (styrene-acrylic acid copolymer) 0.24% by weight
Glycerin 30.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

[Yellow ink composition]
Pigment (PY74) 5.0% by weight
Dispersant (styrene-acrylic acid copolymer) 1.3% by weight
Glycerin 20.0% by weight
1,2-hexanediol 5.0% by weight
BYK-348 0.5% by weight
TEA (triethanolamine) 0.9% by weight
Total remaining amount of pure water 100% by weight

  In each of the above, a pigment, a dispersant, and pure water are mixed and dispersed together with glass beads in a sand mill (manufactured by Yaskawa Seisakusho) for 2 hours, and then glass beads (1.7 mm in diameter, 1.5 times the amount of the mixture). (Weight)) was removed to prepare each pigment dispersion.

  The solvent except the pigment and the dispersant and the resin emulsion were mixed to prepare an ink solvent, and each of the prepared pigment dispersions was added and stirred at room temperature for 20 minutes. Filtration through a 5 μm membrane filter gave each ink composition, and ink sets A to E were obtained.

  Each of the ink sets A to E was accommodated in an ink cartridge, and the ink cartridge was attached to an ink jet printer (manufactured by Seiko Epson Corporation; PM-4000PX). As the recording medium, ink jet exclusive paper (manufactured by Seiko Epson Corporation; MC photographic paper, PM photographic paper, photo print paper) was used, and the printed matter was printed on the recording medium at 1440 × 720 dpi.

(Evaluation of gross change)
At 24 hours after printing, the surface of the print recording medium (PM photo paper, photo print paper) is rubbed with a finger to change the gloss of the print surface (how much finger marks remain on the printed matter and after the color) The degree of pulling) was evaluated visually. The evaluation criteria are as follows.

A: There is no color trailing (fingerprint) on the printed matter B: The color can be slightly trailing (fingerprint) on the printed matter C: The color can be trailing on the printed matter (fingerprint) D: To the extent than C Can pull back (fingerprints)

(Evaluation of surface gloss)
When 24 hours passed after printing, the surface of the printed recording medium (PM photographic paper) was irradiated with fluorescent light, and the color of reflected light from the printed surface and the intensity of reflected light were visually determined. The evaluation criteria are as follows.

A: The reflected light from the printed material is strong, and the reflected light is not colored. B: The reflected light from the printed material is strong, but the reflected light is colored. C: The reflected light from the printed material is not strong compared to A and B. The results of evaluation based on the evaluation criteria are shown below.

(Evaluation of fixability (last name))
When 3 minutes passed after printing, the surface of the printed recording medium (MC photographic paper) was rubbed with a finger, and the extent to which the colorant was peeled was visually evaluated. The evaluation criteria are as follows.

A: Colorant does not peel at all B: Colorant peels slightly (peeling less than 20% of the entire colorant)
C: There is peeling of the colorant (peeling of 20% or more and less than 80% of the whole colorant)
D: The colorant is almost peeled off (80% or more of the whole colorant is peeled)
Table 1 shows the results of evaluation based on the above evaluation criteria.

As shown in Table 1, the ink set A (Example) was extremely superior in gloss change, glossiness, and ink fixability as compared with the ink sets B to E (Comparative Examples).

Claims (8)

  An ink set containing a dark ink composition and a light ink composition having the same color but different color densities, wherein both the dark ink composition and the light ink composition are pigments as colorants An ink set comprising at least a resin as a dispersant and a resin emulsion, wherein the resin emulsion in the dark ink composition is a polyester emulsion, and the resin emulsion in the light ink composition is an alkali-soluble emulsion.   The ink set according to claim 1, wherein the alkali-soluble emulsion is an acrylic resin emulsion.   The ink set according to claim 1 or 2, wherein the alkali-soluble resin of the alkali-soluble emulsion has a weight average molecular weight (Mw) of 8000 or more and 20000 or less.   1. The resin emulsion content (solid content conversion amount) is 0.5% by weight or more and 5.0% by weight or less in the dark ink composition, and 0.1% by weight or more in the light ink composition. The ink set according to claim 1, wherein the ink set is 0% by weight or less.   The cyan ink composition and the magenta ink composition are provided as the dark ink composition at least, and the light cyan ink composition and the light magenta ink composition are provided as the light ink composition. Ink set.   An ink cartridge containing the ink set according to claim 1.   An ink jet recording apparatus comprising the ink set according to claim 1. A recording method for recording by using the ink set according to claim 1 and attaching each ink composition to a recording medium.