JP2012132013A - Ink set for inkjet recording, and inkjet recording method using the same and recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set for inkjet recording for keeping quality of an image long period of time, and to provide an inkjet recording method using the same and a recorded matter.SOLUTION: The ink set for inkjet recording contains at least a magenta ink and a cyan ink, and the magenta ink and the cyan ink respectively comprise a water-soluble organic solvent. The ink set for inkjet recording is characterized in that the content of the water-soluble organic solvent based on the total weight of the magenta ink is lower than the content of the water-soluble organic solvent base on the total weight of the cyan ink, and the inkjet recording method using the same and a recorded matter are provided.

Description

  The present invention relates to an ink set for ink jet recording, an ink jet recording method using the ink set, and a recorded matter, and in particular, an ink jet capable of maintaining image quality for a long period of time in an image obtained by ink jet recording using a plurality of colorants. The present invention relates to a recording ink set, an ink jet recording method using the ink set, and a recorded matter.

  As is well known, the ink jet recording method is a printing method in which printing is performed by causing ink droplets to fly and adhere to a recording medium such as paper. This printing method is capable of printing high-resolution, high-quality images at high speed and easily with an inexpensive device. In particular, in color printing, in recent years, technological development has been carried out as an image forming method that can replace photography. Yes.

The ink used for this ink jet recording generally contains water as a main component and contains a water-soluble organic solvent such as diethylene glycol or glycerin for the purpose of preventing coloring components and clogging of the nozzles of the recording head. It is.
The colorant used in the ink for ink jet recording includes high image quality such as saturation and color reproducibility of the colorant, abundant variety of colorants that can be used, solubility in water, Water-soluble dyes are used from the viewpoint of reliability such as clogging.

However, the dye may be inferior in light resistance, and therefore, the printed matter printed with the dye ink is similarly inferior in light resistance.
In particular, magenta among the color dye inks (yellow, magenta, cyan) has low light resistance, so that the hue balance after light irradiation is lost, and the image appears to be significantly deteriorated.
In addition, if dark and light ink is used to reduce the graininess of the halftone area from the highlight portion, a photographic image can be obtained, but light (thin) ink has much more light resistance than dark ink. The tendency is particularly remarkable in the case of light magenta.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide an ink set for ink jet recording in which image quality is maintained for a long time, an ink jet recording method using the ink set, and It is to provide a record.

  The inventors of the present invention have recently studied ink jet recording using color inks. As compared with yellow and cyan, magenta ink and light magenta ink are subject to deterioration of image quality due to fast fading and discoloration with respect to light. The cause was thought to be related to the amount of water-soluble organic solvent remaining in the image, in addition to the light resistance of the colorant itself. As a result, by adjusting the content of the water-soluble organic solvent with respect to the total amount of the ink in the ink set having the inkjet recording ink, surprisingly, the hue balance of the image is maintained and the image quality is maintained for a long time. I found out. That is, the present invention is as follows.

  An inkjet recording ink set according to the present invention includes at least a magenta ink and a cyan ink, and the magenta ink and the cyan ink each contain a water-soluble organic solvent. It is characterized in that it is set so that “content ratio of water-soluble organic solvent relative to weight” ≦ “content ratio of water-soluble organic solvent relative to the total weight of cyan ink”, whereby the object can be achieved.

  The ink set for inkjet recording according to the present invention includes at least magenta ink, light magenta ink, cyan ink, and light cyan ink, and the magenta ink, light magenta ink, cyan ink, and light cyan ink are each a water-soluble organic solvent. In the ink set for ink jet recording, comprising: “content ratio of water-soluble organic solvent relative to the total weight of light magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” <“water solubility relative to the total weight of light cyan ink” The content of the water-soluble organic solvent is set so as to satisfy “the content of the water-soluble organic solvent relative to the total weight of the cyan ink”, whereby the above-described object can be achieved.

In the ink set for inkjet recording according to the present invention,
The ink set for inkjet recording has a yellow ink,
The water-soluble organic solvent is a high-boiling low-volatile organic solvent;
The high-boiling low-volatile organic solvent is at least one of diethylene glycol, glycerin, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether, and thereby the object can be achieved.

  The ink jet recording method according to the present invention is characterized in that the ink set for ink jet recording is used, whereby the object can be achieved.

  The recorded matter according to the present invention is recorded using the ink set for ink jet recording, and thereby the object can be achieved.

(Function)
The inkjet recording ink set according to the present invention includes at least a magenta ink and a cyan ink, and each of the magenta ink and the cyan ink contains water and a water-soluble organic solvent. The content ratio of the water-soluble organic solvent with respect to the weight ”≦“ the content ratio of the water-soluble organic solvent with respect to the total weight of the cyan ink ”is set. In magenta inks that are considered to be fading and discoloration due to light compared to other colors due to water-soluble organic solvents, the content of water-soluble organic solvents in magenta inks is thus By lowering the water-soluble organic solvent, the fading / discoloration of the magenta and cyan light in the image is less than when using the same ink set for the magenta and cyan inks. The speed difference can be reduced. Thereby, the hue balance of the image can be maintained for a long time after the image formation.

  The ink set for inkjet recording according to the present invention has at least magenta ink, light magenta ink, cyan ink, and light cyan ink, and magenta ink, light magenta ink, cyan ink, and light cyan ink each contain water and a water-soluble organic solvent. In the ink set for ink jet recording, “content ratio of water-soluble organic solvent relative to the total weight of light magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” <“water-soluble organic relative to the total weight of light cyan ink” The content of the solvent is set to satisfy “the content of the water-soluble organic solvent relative to the total weight of the cyan ink”. In this way, by setting the content of the water-soluble organic solvent relative to the total weight of the ink so that the color that is considered to have a greater degree of fading and discoloration to light due to the water-soluble organic solvent, the water-soluble organic solvent is reduced. As compared with the case where ink sets having the same content ratio are used, it is possible to reduce the speed difference of fading and discoloration with respect to light among the magenta, light magenta, cyan and light cyan colors in the image. Therefore, even when trying to form, for example, a photographic image using dark and light inks, the hue balance of the image can be maintained for a long time after the image is formed.

  In the ink set for ink jet recording according to the present invention, since the ink set for ink jet recording has yellow ink, for example, a photographic image can be formed.

  In the ink set for ink-jet recording according to the present invention, the water-soluble organic solvent is a high-boiling low-volatile organic solvent, so that the content of the high-boiling low-volatile organic solvent is the same for magenta ink and cyan ink. Compared with the case of using a set, the speed difference between fading and discoloration with respect to light of magenta and cyan in the image can be reduced more reliably. This makes it possible to maintain the hue balance of the image for a long time after the image formation.

  In the ink set for inkjet recording according to the present invention, the high boiling point and low volatile organic solvent is at least one of diethylene glycol, glycerin, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether. Clogging can be prevented.

  According to the ink jet recording method of the present invention, the hue balance can be maintained for a long time after image formation by simply adjusting the content of the water-soluble organic solvent with respect to the total weight of ink between the colors as in the ink set for ink jet recording. A dripping image can be easily recorded.

  According to the recorded matter according to the present invention, since it was recorded using the ink set for inkjet recording, it can be a recorded matter having an image in which the hue balance is maintained for a long time after the image formation.

  According to the ink set for ink jet recording according to the present invention, in the ink set for ink jet recording having at least magenta ink and cyan ink, and each of magenta ink and cyan ink containing water and a water-soluble organic solvent, “magenta Since the content ratio of the water-soluble organic solvent relative to the total weight of the ink is set so that the "content ratio of the water-soluble organic solvent relative to the total weight of the cyan ink", the content ratio of the water-soluble organic solvent is magenta ink and cyan ink. Compared with the case where the same ink set is used, the speed difference between fading and discoloration of magenta and cyan in the image can be reduced, and the hue balance of the image can be maintained for a long time after image formation. An ink set for inkjet recording can be provided.

  The ink set for inkjet recording according to the present invention has at least magenta ink, light magenta ink, cyan ink, and light cyan ink, and the magenta ink, light magenta ink, cyan ink, and light cyan ink are water and water-soluble organic solvent, respectively. In the ink set for ink jet recording, comprising: “content ratio of water-soluble organic solvent relative to the total weight of light magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” <“water solubility relative to the total weight of light cyan ink” The content ratio of the water-soluble organic solvent ”is set to satisfy“ the content ratio of the water-soluble organic solvent with respect to the total weight of the cyan ink ”. Compare the magenta and line in the image. The speed difference between fading and discoloration with respect to light between magenta, cyan, and light cyan can be reduced, and for example, even when trying to form a photographic image using dark and light ink, a long time after image formation An ink set for ink jet recording that can maintain the hue balance of an image can be provided.

  According to the ink set for ink-jet recording according to the present invention, since the ink set for ink-jet recording has yellow ink, an ink set for ink-jet recording capable of forming a photographic image can be provided.

  According to the ink set for inkjet recording according to the present invention, since the water-soluble organic solvent is a high-boiling low-volatile organic solvent, the content of the high-boiling low-volatile organic solvent is the same between the magenta ink and the cyan ink. Compared to the case of using an ink set, the speed difference between fading and discoloration with respect to light of magenta and cyan in an image can be reduced more reliably. An ink set for ink jet recording that can be maintained can be provided.

  According to the ink set for ink jet recording according to the present invention, the high boiling point low volatile organic solvent is at least one of diethylene glycol, glycerin, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether. It is possible to provide an ink set for ink jet recording that can prevent clogging.

  According to the ink jet recording method of the present invention, as in the ink set for ink jet recording, the hue balance is long after image formation by simply adjusting the content of the water-soluble organic solvent relative to the total weight of ink between colors. An ink jet recording method capable of easily recording an image that is maintained for a period can be provided.

  According to the recorded matter of the present invention, since the recording was performed using the ink set for inkjet recording, it is possible to provide a recorded matter that maintains the image quality for a long period of time after the image formation.

FIG. 5 is a diagram illustrating “difference between cyan image density reduction rate and magenta image density reduction rate” with respect to each amount of light energy when printing is performed using magenta ink, light magenta ink, cyan ink, and light cyan ink. FIG. 5 is a diagram showing “difference between cyan image density reduction rate and magenta image density reduction rate” with respect to each amount of light energy when printing is performed using magenta ink and cyan ink.

  Next, preferred embodiments of the present invention will be exemplified below. However, the present invention is not limited to the following embodiments, and may be appropriately changed within the scope of the matters specifying the invention. It can be done.

  First, each ink used in the ink set for inkjet recording according to the embodiment of the present invention will be described in more detail.

[Magenta ink]
In the ink set for inkjet recording according to the present invention, as the colorant contained in the magenta ink at least one kind,
C. I. Direct Red 2, 4, 9, 23, 26, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 89, 92, 95,
111, 173, 184, 207, 211, 212, 214, 218, 221, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243, 247,
C. I. Acid Red 35, 42, 52, 57, 62, 80, 82, 111, 114, 118, 119, 127, 128, 131, 143, 151, 154, 158, 249, 254, 257, 261, 263, 266, 289, 299, 301, 305, 336, 337, 361, 396, 397,
C. I. Reactive Red 3, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43, 45, 49, 55,
C. I. Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45, 46
And the like.
The amount of the dye added to the magenta ink of the present invention is appropriately determined within a range in which an image having a good hue can be realized in addition to the light resistance and water resistance of the dye. A range of -10 wt% is preferred.

The magenta ink of the present invention contains at least water together with the dye.
Further, the magenta ink of the present invention contains a water-soluble organic solvent, and the water-soluble organic solvent, based on its role, contains a wetting agent that prevents clogging of the nozzles of the recording head, and the ink on the recording medium. Broadly divided into penetrants that help penetration.
Preferred examples of the wetting agent include diethylene glycol, polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, glycerin, and trimethylol. Examples include ethane, trimethylolpropane, urea, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, imidazole, N-methyl-2-pyrrolidone, and can also contain saccharides. As monosaccharides, disaccharide oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldone , Glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose.
Here, the polysaccharide means a saccharide in a broad sense and is used to mean a substance widely existing in nature such as cellulose.
Particularly preferred are high-boiling and low-volatile organic solvents such as diethylene glycol and glycerin because they can reliably prevent clogging of the recording head.
Here, the high boiling point low volatile organic solvent means an organic solvent having a low vapor pressure (0.01 mmHg or less) having a boiling point in the range of 150 ° C. to 300 ° C. The same shall apply hereinafter.
The content of these wetting agents relative to the total weight of the magenta ink is appropriately adjusted in view of the content of the wetting agents in the other color inks so that the hue balance of the image can be maintained for a long time. A range of 20% by weight is preferred.

Preferable examples of the penetrating agent include alkyl ether derivatives of polyhydric alcohols. Specific examples of the alkyl ether derivative of polyhydric alcohol include one or a mixture of two or more selected from diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, and propylene glycol mono-n-butyl ether. be able to. Preference is given to using triethylene glycol mono-n-butyl ether and mixtures containing it.
Particularly preferred is a high boiling point and low volatility such as diethylene glycol mono-n-butyl ether and triethylene glycol mono-n-butyl ether because of its high penetration rate and good print quality without color bleeding. It is an organic solvent.
The addition amount of these polyhydric alcohol alkyl ether derivatives is preferably about 0.5 to 20% by weight, more preferably 3 to 15% by weight, based on the ink to be produced.
However, the water-soluble organic solvent typified by the wetting agent and penetrant is at least lower than the content of the water-soluble organic solvent relative to the total weight of the cyan ink.

  Further, the magenta ink preferably contains a low boiling point organic solvent, and preferable examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, and iso-. Examples include butanol and pentanol. A monohydric alcohol is particularly preferable.

In addition, it is preferable to add a water-soluble resin to the magenta ink according to the present invention in order to make ink physical properties such as viscosity between colors suitable for ink jet recording.
Preferred examples of the water-soluble resin include natural polymers. Specific examples thereof include proteins such as glue, gelatin, casein, and albumin, natural rubbers such as gum arabic and tragacanth, and glucosides such as saponin. And alginic acid and propylene glycol alginate, triethanolamine alginate, ammonium alginate, alginic acid derivatives such as sodium alginate, and cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxyethylcellulose.

  Further, preferred examples of water-soluble resins include synthetic polymers such as polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, vinyl acetate-acrylic esters. Acrylic resins such as copolymers, acrylic acid-alkyl acrylate ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid-alkyl acrylate copolymers, styrene-α-methylstyrene-acrylic acid Copolymer, Styrene-acrylic resin such as styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid, styrene-maleic anhydride, vinylnaphthalene-acrylic acid copolymer, acetic acid Vinyl-ethylene copolymer Examples thereof include polymers, vinyl acetate-fatty acid vinyl ethylene copolymers, vinyl acetate maleate copolymers, and salts thereof.

  Among these, a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and a polymer composed of a monomer having both a hydrophobic group and a hydrophilic group are preferable. Examples of the salt include salts with diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol morpholine, and the like. These copolymers preferably have a weight average molecular weight of about 3,000 to 30,000, more preferably about 5,000 to 15,000.

Further, as the surfactant, an anionic surfactant (for example, sodium dodecylbenzenesulfonate, sodium laurate, ammonium salt of polyoxyethylene alkyl ether sulfate, etc.), a nonionic surfactant (for example, polyoxyethylene alkyl ether) , Polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, etc.), which may be used alone or in combination of two or more. Can be used.
The amount of these water-soluble resins added is determined according to the desired physical properties of the ink, but is preferably in the range of 0.06 to 3% by weight, more preferably in the range of 0.125 to 3% by weight with respect to the dye 1. It is.

Further, a pH adjusting agent can be added to the magenta ink according to the present invention.
It is preferable to adjust the pH of the magenta ink according to the present invention to a range of 5 to 12, more preferably a range of 6 to 10.
Specific examples of the pH adjuster include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, lithium carbonate, sodium phosphate, potassium phosphate, lithium phosphate, diphosphate. Potassium metal such as potassium hydrogen, dipotassium hydrogen phosphate, sodium oxalate, potassium oxalate, lithium oxalate, sodium borate, sodium tetraborate, potassium hydrogen phthalate, potassium hydrogen tartrate, ammonia, methylamine, ethylamine , Amines such as diethylamine, tris (hydroxymethyl) aminomethane hydrochloride, triethanolamine, morpholine, propanolamine and the like are preferable.

  Further, the magenta ink according to the present invention may contain an antioxidant, an ultraviolet absorber, an antiseptic / antifungal agent, a hindered amine light stabilizer and the like.

[Cyan ink]
In the ink set for ink jet recording according to the present invention, the components of the cyan ink are the same as those in the above-mentioned [magenta ink] except that the magenta dye is replaced with a cyan dye as a colorant.
As a colorant contained in one or more cyan inks,
C. I. Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 80, 84, 86, 87, 90, 98, 106, 108, 109, 151, 156, 158, 159, 160, 168, 189, 192, 193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 229, 236, 237, 244, 248, 249, 251, 252, 264, 270, 280, 288, 289, 291,
C. I. Acid Blue 9, 25, 40, 41, 62, 72, 76, 78, 80, 82, 92, 106, 112, 113, 120, 127: 1, 129, 138, 143, 175, 181, 205, 207, 220, 221, 230, 232, 247, 258, 260, 264, 271, 277, 278, 279, 280, 288, 290, 326
And the like.
The content of these water-soluble organic solvents relative to the total weight of the cyan ink is appropriately adjusted in view of the content of the water-soluble organic solvent in the other color inks so that the hue balance of the image can be maintained for a long time. A range of from 30% to 30% by weight is preferred. In this case, at least the content of the water-soluble organic solvent with respect to the total weight of the magenta ink is set to be higher. The content of additives other than the water-soluble organic solvent with respect to the total weight of the cyan ink is the same as the numerical range described in [Magenta ink].

[Light magenta ink]
“Light magenta ink” refers to a plurality of magenta inks in the same ink set that have a low reflection density when recorded on a recording medium. Other than that. More specifically, the addition amount of the dye in the light magenta ink is 50% or less of the magenta ink.
As a colorant for light magenta ink, one or more dyes similar to those used in the magenta ink described above can be contained.
The other components other than the colorant are the same as in the case of [Light magenta ink], but the content of the water-soluble organic solvent relative to the total weight of the light magenta ink is such that the hue balance of the image can be maintained for a long time. In view of the content of the water-soluble organic solvent in the other color ink, it is appropriately adjusted and is preferably in the range of 5% by weight to 20% by weight. However, the content of the water-soluble organic solvent with respect to the total weight of the light magenta ink is at least equal to or lower than the content of the water-soluble organic solvent with respect to the total weight of the magenta ink. The content of additives other than the water-soluble organic solvent with respect to the total weight of the light magenta ink is the same as the numerical range described in [Magenta ink].

[Light cyan ink]
“Light cyan ink” refers to a plurality of cyan inks in the same ink set that have a low reflection density when recorded on a recording medium. Say. More specifically, the addition amount of the dye in the light cyan ink is 50% or less of the cyan ink.
As a colorant for light cyan ink, one or more dyes similar to the dyes used in the cyan ink described above can be contained.
The other components other than the colorant are the same as in the case of [Light Cyan Ink], but the content of the water-soluble organic solvent relative to the total weight of the light cyan ink is different from other colors so that the hue balance of the image can be maintained for a long time. In view of the content of the water-soluble organic solvent in the ink, it is appropriately adjusted, and the range of 7.5 wt% to 25 wt% is preferable. However, the content of the water-soluble organic solvent relative to the total weight of the light cyan ink is at least equal to or lower than the content of the water-soluble organic solvent relative to the total weight of the cyan ink and higher than the content of the water-soluble organic solvent relative to the total weight of the magenta ink. To be. Preferably, the content of the water-soluble organic solvent relative to the total weight of the light cyan ink is set lower than the content of the water-soluble organic solvent relative to the total weight of the cyan ink. The content of the additives other than the water-soluble organic solvent with respect to the total weight of the light cyan ink is the same as the numerical range described in [Magenta ink].

  As described above, the inkjet recording ink set according to the embodiment of the present invention includes at least a magenta ink and a cyan ink, and each of the magenta ink and the cyan ink contains a water-soluble organic solvent. In the set, “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of cyan ink” is set. Therefore, in a magenta ink that is considered to be significantly fading or discolored with respect to light due to the water-soluble organic solvent, the content of the water-soluble organic solvent in the magenta ink is thus cyan. Since the water-soluble organic solvent is lower than the water-soluble organic solvent in the ink, the content of the water-soluble organic solvent with respect to magenta and cyan light in the image is lower than when using the same ink set for magenta ink and cyan ink. The speed difference between fading and discoloration can be reduced. Thereby, the hue balance of the image can be maintained for a long time after the image formation.

  The ink set for inkjet recording according to the present invention includes at least magenta ink, light magenta ink, cyan ink, and light cyan ink, and each of magenta ink, light magenta ink, cyan ink, and light cyan ink contains a water-soluble organic solvent. In the ink set for ink jet recording, “content ratio of water-soluble organic solvent relative to the total weight of light magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” <“water-soluble organic relative to the total weight of light cyan ink” Since the content of the solvent is set so that the content ratio of the water-soluble organic solvent relative to the total weight of the cyan ink, the content ratio of the water-soluble organic solvent is compared with the case of using an ink set with the same content Magenta, light magenta , It is possible to reduce the speed difference between the fading, discoloration for cyan and light cyan light between the respective colors. Therefore, even when the dark and light inks are used in this way to form a photographic image, for example, the hue balance of the image can be maintained for a long time after the image is formed.

  The ink set for inkjet recording according to the present invention is preferably a combination of a magenta ink, a light magenta ink, a cyan ink, and a light cyan ink, preferably a yellow ink, a dark yellow ink, and a black ink. In addition, it is preferable to use a total of 4 to 7 color ink sets having all of yellow and yellow colors because, for example, a photographic image can be formed.

Examples of the dye used for the yellow ink include CI direct yellow 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53, 58, 59, 68, 86, 87, 93, 95, 96, 98, 100, 106, 108, 109, 110, 130, 132, 142, 144, 161, 163, CI direct yellow 86 and / or 132 should be used Is preferred.
Examples of the dye used for the black ink include CI direct black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97, 108, 112, 113, 114, 117, 118, 121, 122, 125, 132, 146, 154, 166, 168, 173, 199.

In addition, the yellow ink, dark yellow ink and black ink preferably contain at least water and a water-soluble organic solvent together with the dye, preferably contain a low-boiling organic solvent, a water-soluble resin, a pH adjuster, As in the case of the magenta ink, it is preferable to add an antiseptic / antifungal agent or the like.
In addition, the addition amount of the dye in the dark yellow ink with respect to the total weight of the ink is an amount that is 1.5 times or more that of the yellow ink.

  The ink jet recording method according to the present invention can be performed by applying an ink cartridge which is an embodiment of an ink set to a known ink jet printer. Therefore, by the ink jet recording method according to the present invention, that is, by simply adjusting the content of the wetting agent with respect to the total weight of ink between the colors, it is possible to easily record an image whose hue balance is maintained for a long time after image formation. Can do.

  Further, since the recorded matter printed in this way is recorded using the ink set for ink jet recording according to the embodiment of the present invention, an image whose hue balance is maintained for a long time after the image formation is obtained. It can be set as a recorded matter.

  Next, the present invention will be specifically described with reference to examples of the present invention, but the present invention is not limited thereto.

(Example)
Magenta ink, light magenta ink, cyan ink, light cyan ink, and yellow ink were prepared as in the following compositions.

[Magenta ink]
・ C. I. Direct Red 227 (Magenta dye) 4% by weight
・ Styrene-acrylic acid copolymer (molecular weight = 7000) (water-soluble resin) 2% by weight
・ Diethylene glycol (wetting agent) 5% by weight
・ Glycerin (wetting agent) 5% by weight
・ Triethylene glycol mono-n-butyl ether (penetrating agent) 5% by weight
-Potassium hydroxide (pH adjuster) 0.2% by weight
・ Pure water balance

  According to the above composition, a magenta ink containing 15% by weight of a water-soluble organic solvent was obtained.

[Light magenta ink]
C. I. Direct Red 227 was changed to 2% by weight, styrene-acrylic acid copolymer was 3% by weight, and water-soluble organic solvents diethylene glycol, glycerin and triethylene glycol mono-n-butyl ether were respectively 5% by weight, 2.5% A light magenta ink containing 12.5% by weight of a water-soluble organic solvent was obtained by using the same composition as that of the magenta ink except that the amount was 5% by weight and 5% by weight.

[Cyan ink]
The magenta dye is a cyan dye, C.I. I. Direct blue 199 (4% by weight), styrene-acrylic acid copolymer 1% by weight, water-soluble organic solvents diethylene glycol, glycerin and triethylene glycol mono-n-butyl ether 10% by weight, 10% by weight, respectively A cyan ink containing 30% by weight of a water-soluble organic solvent was obtained by using the same composition as that of the magenta ink except that the amount was 10% by weight.

[Light cyan ink]
C. I. Direct Blue 199 was changed to 1% by weight, styrene-acrylic acid copolymer was 2% by weight, and water-soluble organic solvents diethylene glycol, glycerin and triethylene glycol mono-n-butyl ether were 10% by weight and 5% by weight, respectively. A light cyan ink containing 25% by weight of a water-soluble organic solvent was obtained by using the same composition as the cyan ink except that the amount was 10% by weight.

[Yellow ink]
The yellow ink of the color ink cartridge IC5CL05 (trade name of Seiko Epson Corporation) was used as it was.

  The magenta ink, light magenta ink, cyan ink, and light cyan ink prepared as described above were refilled into a color ink cartridge IC5CL05 (trade name of Seiko Epson Corporation) to produce an ink cartridge of the example.

(Comparative example)
In each of the magenta ink, light magenta ink, cyan ink, and light cyan ink, the water-soluble organic solvents diethylene glycol, glycerin, and triethylene glycol mono-n-butyl ether are 10% by weight, 5% by weight, and 10% by weight, respectively. The ink cartridge of the comparative example was produced by setting it as the composition similar to the Example except having made 1 weight% of styrene-acrylic acid copolymers.

The examples and comparative examples were evaluated by the methods described below.
(1) Image quality test immediately after image formation Using the ink cartridges produced in the examples and comparative examples and the black ink cartridge IC5BK05 (trade name of Seiko Epson Corporation), PM photo paper (trade name of Seiko Epson Corporation) An image name portrait (sample number 1, image identification symbol N1) of high-definition color digital standard image data (ISO / JIS-SCID) was printed. Printing was performed using an inkjet printer PM-800C (trade name of Seiko Epson Corporation) and an inkjet printer EM-900C (trade name of Seiko Epson Corporation) as printers. As a result of visual observation of the sharpness of the image immediately after the image formation, it was confirmed that the image was colorfully reproduced in any case in the ink cartridge filled with the ink prepared in Examples and Comparative Examples. . The ink jet printer PM-800C is a printer designed to print a total of six colors, magenta ink, light magenta ink, cyan ink, light cyan ink, yellow ink, and black ink, and is an ink jet printer EM-900C. Is a printer designed to print a total of four colors, magenta ink, cyan ink, yellow ink and black ink.

(2) Hue balance test Magenta and cyan images on PM photographic paper (manufactured by Seiko Epson Corporation) using the ink cartridges produced in the examples and comparative examples, the ink jet printer PM-800C, and the ink jet printer EM-900C. Printing was performed so that the density (OD value) was about 1.0. The obtained image, using a xenon fade meter (C135A), were each acceleration test at each light energy of ^{15kJ / m 2, 30kJ / m} 2, 45kJ / m 2. Measure the OD value before and after the test with a spectrophotometer Gretag SPM100-II (manufactured by Gretag)

“Density reduction rate (%)” = “OD value after acceleration test / OD value before acceleration test” × 100

Thus, the density reduction of each color printing was compared. “Cyan image density reduction rate and magenta for each light energy amount when printing using a total of four colors of magenta ink, light magenta ink, cyan ink and light cyan ink (when using inkjet printer PM-800C) The difference in the image density reduction rate ”is shown in Table 1, and a graph of this is shown in FIG. Further, when printing is performed using a total of two colors of magenta ink and cyan ink (when the ink jet printer EM-900C is used), “cyan image density reduction rate and magenta image density reduction rate” The difference is shown in Table 1, and a graph of this difference is shown in FIG.

  From the above results, it was possible to reproduce the image quality satisfactorily when performing color printing by using the ink cartridge which is an embodiment of the ink set for inkjet recording according to the present invention. In addition, both “when printing using a total of four colors of ink, magenta ink, light magenta ink, cyan ink and light cyan ink” and “when printing using a total of two colors of magenta ink and cyan ink” Compared to the case of using the ink cartridge of the comparative example (the ink cartridge in which the content of the water-soluble organic solvent is equivalent to each color), the ink cartridge of the example “the cyan image density reduction rate and the magenta density reduction rate The difference was small, and the speed difference between fading and discoloration with respect to light between magenta and cyan in the image could be reduced. Therefore, it is possible to obtain a recorded matter that maintains the image quality for a long time by maintaining the hue balance of the image after the image formation.

Claims (7)

  In an ink jet recording ink set having at least a magenta ink and a cyan ink, and each of the magenta ink and the cyan ink each containing water and a water-soluble organic solvent, the “content ratio of the water-soluble organic solvent relative to the total weight of the magenta ink” An ink set for ink-jet recording, which is set to satisfy “≦ content of water-soluble organic solvent relative to the total weight of cyan ink”.   Ink for inkjet recording, comprising at least magenta ink, light magenta ink, cyan ink, and light cyan ink, wherein the magenta ink, light magenta ink, cyan ink, and light cyan ink each contain water and a water-soluble organic solvent. In the set, “content ratio of water-soluble organic solvent relative to the total weight of light magenta ink” ≦ “content ratio of water-soluble organic solvent relative to the total weight of magenta ink” <“content ratio of water-soluble organic solvent relative to the total weight of light cyan ink” ≦ “ An ink set for ink-jet recording, which is set so as to have a "content ratio of a water-soluble organic solvent relative to the total weight of cyan ink".   The ink set for ink-jet recording according to claim 1 or 2, wherein the ink set for ink-jet recording has a yellow ink.   The ink set for inkjet recording according to any one of claims 1 to 3, wherein the water-soluble organic solvent is a high-boiling low-volatile organic solvent.   The ink for inkjet recording according to claim 4, wherein the high-boiling low-volatile organic solvent is at least one of diethylene glycol, glycerin, diethylene glycol mono-n-butyl ether, and triethylene glycol mono-n-butyl ether. set.   An ink jet recording method using the ink set for ink jet recording according to claim 1.   A recorded matter recorded using the ink set for ink jet recording according to claim 1.