JP2001226615A - Ink set for ink jet-recording and ink jet-recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set for ink jet-recording capable of obtaining a sufficient image density, showing a good light fastness and having a good reliability regarding to the drying property and ejection of the ink, and an ink-jet recording method. SOLUTION: An ink for the ink jet-recording contains water, a water-soluble organic solvent and a coloring material; the ink set for the ink jet recording having a light fastness-improving liquid for the ink jet-recording containing water, an organic ultraviolet light-absorbing agent and a nonionic surfactant, and the method for recording by using the above ink, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ink jet recording ink set and an ink jet recording method used for an ink jet recording apparatus, for example, a printer, a copying machine, a facsimile, a word processor, a plotter and the like.

[0002]

2. Description of the Related Art A so-called ink jet recording apparatus which discharges a liquid or a molten solid ink from a nozzle, a slit, a porous film or the like, and performs recording on paper, cloth, film, or the like is small, inexpensive, quiet, etc. Vigorous studies are being conducted because of the advantages. Recently, many products capable of full-color recording, which can provide good printing quality on so-called plain paper such as copy paper, are commercially available, and occupy a large position in the field of recording apparatuses.

[0003] The ink used in the ink jet recording apparatus mainly contains a solvent, a coloring material and additives. It is desired that the inkjet ink has the following properties (1) to (5). That is, (1) bleeding on paper,
A high-resolution, high-density, uniform image without fogging can be obtained; (2) No clogging due to ink drying at the nozzle tip, always good ejection responsiveness and ejection stability; (3) ) Good drying properties of the ink on paper; (4) good image fastness; and (5) good long-term storage stability.

The fastness of the image (4) includes water fastness, light fastness, and rub fastness. In recent years, an ink jet printer has been used to output a photograph taken by a digital camera. There is also a relation to be compared, and there is a tendency that light resistance is emphasized. In addition, printed materials such as posters for outdoor use are also printed by an ink jet printer, and light resistance is naturally an important characteristic in such applications.

[0005] As a method for improving the light fastness of an image, several methods described below have been proposed. For example, JP
As shown in JP-A-11-61015 and JP-A-11-116873, it has been proposed to improve light fastness by using a new dye. However, these are merely improvements in the light fastness of one color ink, and it is doubtful that secondary colors or tertiary colors can exhibit high light fastness. Due to the color difference, the color balance of the image deteriorates.

Further, Japanese Patent Application Laid-Open Nos. 9-254522 and
In JP-78218, a benzotriazole-based ultraviolet absorber is contained in an ink receiving layer to prevent fading. JP
In JP-A-5-335578, an antioxidant is added to silica-coated paper to prevent fading due to oxidation. However, in the case of a method in which a specific substance is added to a recording medium as described above, high light resistance can be naturally exhibited only on a specific recording medium.

Further, Japanese Patent Application Laid-Open No. 7-97540 discloses that a benzotriazole-based material as an ultraviolet absorber is contained in ink to prevent discoloration. However, in this case, the benzotriazole-based material is added to the colored polyester emulsion, and the clogging resistance and the storage stability of the ink cannot be said to be sufficient. JP-A-8-60059 discloses that a cerium oxide-based ultraviolet absorber is contained in an ink or contained in a colorless liquid,
A method of attaching a recording material before or after the ink is provided. However, in this case, there are problems in that the light resistance is not sufficient, the storage stability of the ink or the colorless liquid, and the drying property on the recording material.

Japanese Patent Application Laid-Open No. 10-278379 discloses a method in which a surface modifier such as silica / alumina containing an ultraviolet absorber is applied, dried, and then printed with ink. However, in this case, a drying device is required, which requires space / time / energy. Also,
In addition to these, the precondition is the surface modification of plain paper, and in glossy paper for inkjet or inkjet coated paper, the surface treatment layer is rather disturbed, and the image quality of the recorded image is degraded. Furthermore, since silica / alumina and the ultraviolet absorber are mixed and dispersed, the storage stability of the surface modifier is low.

As described above, no matter what kind of paper is used for printing, high color development and good light fastness are exhibited, the color balance of the image is not lost, and there are also problems with ink drying and storage stability. No inkjet ink sets and inkjet recording methods have been found.

[0010]

As described above, measures for improving the light fastness of an image have been proposed in the past, but none of these methods has reached a level that can sufficiently satisfy the requirements. That is, an object of the present invention is to provide an ink jet recording ink set and an ink jet recording method, which can obtain a sufficient image density, exhibit good light fastness, and have good drying properties and ejection reliability of the ink. And

[0011]

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have found that ink for inkjet recording containing water, a water-soluble organic solvent and a coloring material; water, an organic ultraviolet absorber,
It has been found that the above object can be achieved by using an ink set for ink jet recording comprising a light resistance improving liquid for ink jet recording containing a nonionic surfactant and, if desired, a dispersant. Reached.

The present inventors have found the following inventions <1> to <11>. That is, <1> an ink for inkjet recording containing water, a water-soluble organic solvent and a coloring material; and a lightfastness improving liquid for inkjet recording containing water, an organic ultraviolet absorber and a nonionic surfactant. Ink set for inkjet recording. <2> In the above item <1>, the viscosity of the light resistance improving liquid for ink jet recording is 1.3 to 7.0 mPa · s, the surface tension is 20 mN / m to 50 mN / m, and the conductivity is 0.000.
The pH is preferably 1 to 3.0 S / m and the pH is 4 to 12.

<3> In the above item <1> or <2>,
The UV absorber is preferably a benzotriazole-based compound, a benzophenone-based compound, or a salicylate-based compound. <4> In any one of the above items <1> to <3>, the lightfastness improving liquid for inkjet recording may contain at least a compound selected from the group consisting of a cationic polymer, a cationic saccharide, and an organic quaternary ammonium salt. It is better to further contain one kind.

<5> In any one of the above items <1> to <3>, it is preferable that the ink jet recording ink is composed of at least a cyan ink, a magenta ink, a yellow ink and a black ink. <6> In the above item <5>, at least one of the cyan ink, the magenta ink, the yellow ink and the black ink further contains a light-colored photo ink, and the maximum value in the absorbance spectrum of the light-colored ink is 1 The maximum value is preferably イ ン ク to 1/10 of the maximum value in the absorbance spectrum of the color ink.

<7> In any one of the above items <1> to <6>, the light fastness improving liquid may further contain a dispersant. <8> In the above item <7>, the dispersant may be a polymer dispersant. <9> In any one of the above items <1> to <8>, the nonionic surfactant is a polyoxyethylene polyoxypropylene block copolymer, tetramethyldesinediol, tetramethyldesinediol ethylene oxide adduct, polyoxyethylene higher It is preferably an alkyl ether.

<10> An ink jet recording ink containing water, a water-soluble organic solvent, and a coloring material; and a lightfastness improving liquid for ink jet recording containing water, an organic ultraviolet absorber, and a nonionic surfactant. An ink jet recording method in which recording is performed on a recording material by discharging from an orifice according to the conditions. <11> In the above item <10>, the discharge amount of the ink and the light resistance improving liquid per drop is 0.01 to 30 n.
g.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The ink set for ink jet recording according to the present invention includes an ink for ink jet recording and a lightfastness improving liquid for ink jet recording. Hereinafter, each will be described.

The light resistance improving liquid for ink jet recording is
It contains water, an organic ultraviolet absorber, and a nonionic surfactant as essential components, and may further contain a dispersant, if desired. The organic ultraviolet absorber used in the present invention is preferably an ultraviolet absorber such as a benzophenone-based compound, a benzotriazole-based compound, or a salicylate-based compound in consideration of the ultraviolet absorption effect and the storage stability of the lightfastness improving liquid for inkjet recording itself. preferable. In particular, benzotriazole-based compounds are preferred in terms of storage stability, and among them, 2-2-2-hydroxy-3-t-butyl-5-methyl-phenyl-5-chlorobenzotriazole is most preferred. The content of the organic ultraviolet absorber is the light resistance improving liquid 1 for inkjet recording.
In 00 wt%, the range is preferably 0.01 to 10 wt%, more preferably 0.05 to 5 wt%.

(Dispersant) Since this organic ultraviolet absorber has low water solubility, it is preferable to use it together with a dispersant. As the dispersant, those generally used as a pigment dispersant can be used. For example, in addition to classical anionic, nonionic and cationic dispersants, polymer dispersants such as polysulfonate dispersants such as alkylnaphthalenesulfonic acid formalin condensate; (meth) acrylic acid- (meth) acrylic Polycarboxylate dispersants such as acid ester copolymers and styrene-maleic anhydride copolymers; polyphosphate dispersants such as hexametaphosphate; nonionic polymer dispersants such as other oxyethylene compounds A cationic polymer dispersant such as polyethyleneimine; and an anionic dispersant having another nonionic unit. Among them, a polymer dispersant is particularly preferable in order to further exhibit effects such as storage stability of the light resistance improving liquid for recording.

(Nonionic Surfactant) The nonionic surfactant, when present in the lightfastness improving liquid of the present invention, lowers its surface tension and causes the lightfastness improving liquid to wet a recording medium or a head. Exhibits the function of adjusting the permeability / permeability.
In addition, the nonionic surfactant also has a function of improving the dispersion stability of the ultraviolet absorber.

Examples of these nonionic surfactants include polyoxyethylene polyoxypropylene block copolymer, tetramethyldecine diol ethylene oxide adduct, and polyoxyethylene higher alkyl ether. These are highly permeable and are desirable from the viewpoint of improving the drying property and image quality on paper. The content of the nonionic surfactant is 100% by weight of the light resistance improving liquid.
Medium, 0.001 to 5 wt%, preferably 0.005 to 3
It is good to be wt%.

By using a combination of an organic ultraviolet absorber and a nonionic surfactant in the light fastness improving liquid of the present invention, if desired, further combining these with a dispersant, the light fastness is increased. Not only will it be improved,
It exerts its effects in terms of image quality such as an increase in optical density (OD) and a reduction in feathering / ICB. Furthermore, since there is no problem in terms of dischargeability and storage stability of the light resistance improving liquid,
It can be used for inkjet applications.

(Water) In the light fastness improving liquid of the present invention, water is used as a main solvent of an organic ultraviolet absorbent and a nonionic surfactant and, if desired, a dispersant for discharging by ink jet. In addition to water, a water-soluble organic solvent may be contained as a sub-solvent for preventing evaporation of water. The water-soluble organic solvent is preferably a polyhydric alcohol, a polyhydric alcohol ether, a sulfur-containing solvent, a nitrogen-containing solvent, or the like.

Further, the lightfastness improving liquid for ink jet recording of the present invention may contain at least one compound selected from a cationic polymer, a cationic saccharide and an organic quaternary ammonium salt. These compounds mainly have an effect of improving water resistance, but also contribute to improvement of image density and further improvement of light resistance. The mechanism of the improvement in light resistance is not necessarily clear, but by containing these compounds, the coloring material in the ink aggregates to improve the water resistance and suppress the penetration of the coloring material into the paper. It is presumed that the light resistance is also improved in order not to make the distance to the ultraviolet absorbent long. In addition, the lightfastness improving liquid for inkjet recording may contain a pH adjuster, a physical property adjuster, an antioxidant, a fungicide, a rust preventive, a bactericide, and the like.

The light resistance improving liquid for ink jet recording of the present invention has a surface tension of 50 mN / m or less, preferably 20 to 50 mN / m, more preferably 20 to 45 mN / m. . If the surface tension is too high, the wettability to the recording material is poor, and the drying property tends to be insufficient. On the other hand, if the surface tension is too low, bleeding or strike-through tends to occur when the ink is printed because the recording material is too wet.

The steady-state flow viscosity of the lightfastness improving liquid for ink jet recording is 1.3 to 7.0 mPa · s, preferably 1.
The pressure is preferably 5 to 5.0 mPa · s. If this value is too low, the supply to the nozzles tends to be excessive, and a phenomenon such as face flooding tends to occur. On the other hand, if this value is too high, the resistance to the ejection force tends to increase.

If the conductivity of the lightfastness improving liquid for ink-jet recording is too high, it can easily cause a head failure, and is preferably in the range of 0.0001 to 3.0 S / m. Furthermore, the pH of the lightfastness improving liquid for inkjet recording
Takes into account the erosion of the head and cartridge members,
H4-12, preferably pH5-11.

(Ink Set for Ink Jet Recording) The ink set for ink jet recording of the present invention contains water, a water-soluble organic solvent and a coloring material as essential components. That is,
As the ink for inkjet recording in the present invention, basically, an ink having a composition usually used in an inkjet ink can be used.

(Coloring Material) As the coloring material used in the ink jet recording ink, various dyes, pigments, oil emulsions colored with oil-soluble dyes and pigments, colored polymers / waxes, and the like can be used. As the coloring material, a pigment is more advantageous in terms of discoloration and fading. However, in the case of a color pigment, a dye is preferred because of problems in color development and transmittance. In the case of the dye, from the viewpoint of solubility and storage stability, a water-soluble anionic dye having a substituent selected from the group consisting of at least a carboxylic acid and a salt thereof as a solubilizing group; and a sulfonic acid and a salt thereof is more preferable. Is preferably an acid dye or a direct dye.

For example, CI Direct Black-2, -4,
-9, -11, -17, -19, -22, -32, -80, -151, -154, -16
8, -171, -194, 195; CI Direct Blue-1, -2,-
6, -8, -22, -34, -70, -71, -76, -78, -86, -112, -1
42, -165, -199, -200, -201, -202, -203, -207, -21
8, -236, -287, -307; CI Direct Red-1, -2,-
4, -8, -9, -11, -13, -15, -20, -28, -31, -33, -3
7, -39, -51, -59, -62, -63, -73, -75, -80, -81, -8
3, -87, -90, -94, -95, -99, -101, -110, -189, -22
7; CI Direct Yellow-1, -2, -4, -8, -11, -1
2, -26, -27, -28, -33, -34, -41, -44, -48, -58, -8
6, -87, -88, -132, -135, -142, -144, -173; CI Direct Violet 107; CI Food Black-1,-
2; CI Acid Black-1, -2, -7, -16, -24, -26,
-28, -31, -48, -52, -63, -107, -112, -118, -119,-
121, -156, -172, -194, -208; CI Acid Blue-
1, -7, -9, -15, -22, -23, -27, -29, -40, -43, -5
5, -59, -62, -78, -80, -81, -83, -90, -102, -104,
-111, -185, -249, -254; CI Acid Red-1, -4,
-8, -13, -14, -15, -18, -21, -26, -35, -37, -52,-
110, -144, -180, -249, -257; CI Acid Yellow-
1, -3, -4, -7, -11, -12, -13, -14, -18, -19, -23,
-25, -34, -38, -41, -42, -44, -53, -55, -61, -71,
-76, -78, -79, -122 and the like.

Among the above, dyes which are originally slow in decomposition by ultraviolet light and have high light resistance are preferred. That is, CI Direct Blue-86, -199, -307 as a cyan dye;
And CI Acid Blue-249, CI as magenta dye
Direct Red-75; and CI Acid Red-37, CI Direct Yellow-86, -132,-as the yellow dye
142, -144, -173, and CI Food Black-2 as black dye; and CI Direct Black -154, -16
It is preferable to use a dye selected from 8, and -195 as the main component dye in the ink, including the point of coloring.

In the case of a black ink, there is generally a method of using carbon black as a pigment for a coloring material. However, when printing on glossy paper for inkjet, the carbon black ink tends to give a matte feeling as if the carbon black ink was thickly applied to the surface of the paper. Therefore, when printing a photographic image on glossy paper, dye ink is more preferable.

The content of these coloring materials is in the range of 0.05 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.1 to 7% by weight, based on 100% by weight of the ink for ink jet recording. It is good. If the content of the coloring material is too large, clogging when water evaporates at the nozzle tip tends to deteriorate. Also, if the content is small, a sufficient image density tends not to be obtained.

In recent ink-jet ink printers, in order to reduce the granularity of an image, a light-colored ink having a reduced colorant density is usually provided or optionally provided in addition to an ink set having a normal colorant density. Often. Also in the present invention, each color, the intensity of the maximum value in the absorbance spectrum with respect to the normal ink is 1/2 to 2
The ink set may include a light-colored ink having a color material density reduced to 1/10. In general, when a light-colored ink is used, the amount of the coloring material is small. Therefore, the ink set for ink jet recording of the present invention works effectively with light color ink.

The ink jet recording ink of the present invention comprises:
In addition to the coloring material, it contains water and a water-soluble organic solvent as essential components. The water-soluble organic solvent is used to prevent evaporation of water in the ink jet recording ink. Examples of these include ethylene glycol, diethylene glycol, propylene glycol, polyethylene glycol, triethylene glycol, glycerin, trimethylolpropane, 1,2,6-hexanetriol,
Polyhydric alcohols such as 5-pentanediol and dipropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether,
Glycol ethers such as propylene glycol monomethyl ether and propylene glycol monobutyl ether; sulfur-containing solvents such as thiodiethanol, 2-mercaptoethanol, thioglycerol, sulfolane, dimethyl sulfoxide; 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl Nitrogen-containing solvents such as pyrrolidone, triethanolamine, diethanolamine and the like.

In consideration of nozzle clogging in a head with a reduced drop amount, sulfur-containing solvents and nitrogen-containing solvents are more preferable. Even if these are used alone,
More than one kind may be mixed. However, if the content of these water-soluble organic solvents is too large, the viscosity of the ink increases, and the ejection stability and ejection responsiveness decrease. Therefore, the amount of these solvents is 100% by weight of the inkjet recording ink.
It is preferably about 1 to 60% by weight, preferably about 5 to 40% by weight.

The ink for ink-jet recording may further contain additives. For example, it may contain a surfactant. This surfactant has a function of reducing the surface tension of the ink and adjusting the wettability of the ink on a recording medium or a head. As the surfactant, any of nonionic, anionic, cationic, and amphoteric surfactants can be used. In many cases, an anionic dye is used as a coloring material. Therefore, it is preferable to use a nonionic surfactant, an anionic surfactant, or an amphoteric surfactant in consideration of dye dissolution stability.

For example, nonionic surfactants include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid Ester, polyoxyethylene sorbite fatty acid ester, polyoxyethylene sterol, polyoxyethylene polyoxypropylene ether, polyoxyethylene fatty acid amide, polyoxyethylene polyoxypropylene block copolymer, tetramethyldesinediol, tetramethyldesinediol ethylene oxide adduct And so on.

As anionic surfactants, alkyl benzene sulfonate, alkyl phenyl sulfonate, alkyl naphthalene sulfonate, higher fatty acid salt,
Higher fatty acid ester sulfate, higher fatty acid ester sulfonate, higher alcohol ether sulfate and sulfonate, higher alkyl sulfosuccinate, naphthalene sulfonate formalin condensate, polystyrene sulfonate, polyacrylic Acid salts, polyoxyethylene alkyl ether phosphates, alkyl ether carboxylates, alkyl sulfates, acrylic acid-acrylate copolymers and the like.

Further, as the amphoteric surfactant, betaine, sulfobetaine, sulfate betaine, imidazoline and the like can be used. In addition, silicone-based surfactants such as polysiloxane polyoxyethylene adducts and fluorine-based surfactants such as perfluoroalkyl carboxylate, perfluoroalkyl sulfonate and oxyethylene perfluoroalkyl ether, spiculisporic acid, Biosurfactants such as rhamnolipid and lysolecithin can also be used. The amount of the surfactant added is in the range of 0.001 to 5% by weight, preferably 0.0%, based on 100% by weight of the inkjet recording ink.
The content is preferably in the range of 0.5 to 3% by weight.

The ink-jet recording ink of the present invention comprises:
Other additives can be included. Other additives include pH adjusters, for example, hydrochloric acid, sulfuric acid,
Nitric acid, acetic acid, citric acid, oxalic acid, malonic acid, boric acid,
Acids such as phosphoric acid, phosphorous acid and lactic acid; sodium hydroxide,
Bases such as potassium hydroxide, lithium hydroxide and ammonia; and various buffers such as phosphates, oxalates, amine salts and Good buffer are used.

The p of the ink for ink jet recording of the present invention
H is p considering the erosion of the head and the cartridge member.
H4-12, preferably pH5-11.
The ink jet recording ink of the present invention may contain an antioxidant as an auxiliary role for improving light fastness. The addition amount of the antioxidant in 100% by weight of the inkjet recording ink is 0.001 to 3% by weight, preferably 0.001% by weight.
It is preferably in the range of 1 to 1% by weight. Further, these antioxidants may be added to glossy paper or coated paper, or may be added to a laminate film.

The ink-jet recording ink of the present invention comprises:
Polyethyleneimine, polyamines as physical property modifiers,
Polyvinylpyrrolidone, polyethylene glycol, cellulose derivatives, etc .; cyclodextrin, polycyclodextrin, macrocyclic amines, crown ethers, etc. as inclusion compounds; acetamide, betaine, urea and analogs thereof may be contained as solubilizers If necessary, a fungicide, a rust preventive, a bactericide, a chelating agent, a dendrimer and the like may be contained.

The ink jet recording ink of the present invention has a surface tension of 20 mN / m
Not less than 45 mN / m or less, preferably 25 to 43 m
It is preferably in the range of N / m. If the value of the surface tension is too high, the wettability to the recording material is poor, and the drying property of the ink tends to be insufficient.
Bleeding between colors called B) tends to worsen. If the value of the surface tension is too low, the recording material is too wet, and bleeding or strike-through tends to occur.

The steady flow viscosity of the ink is 1.4 to
5.0 mPa · s range, preferably 1.7 to 4.0 m
It is good to be in the range of Pa · s. If the value is too low, the ink supply to the nozzles tends to be excessive, which causes a phenomenon such as face flooding, which causes the flashing light. Further, the conductivity of the ink is
If it is too high, it is likely to cause a head failure. Therefore, it is preferably in the range of 0.001 to 3.0 S / m.

The ink set for ink jet recording of the present invention comprises the ink for ink jet recording described above and a light resistance improving liquid for ink jet recording. By using the ink set for inkjet recording of the present invention, it is possible to achieve the object of the present invention that a sufficient image density is obtained, good light fastness is obtained, and ink drying property and discharge reliability are good. Can be.

As described above, the good result was obtained because the organic ultraviolet absorbent in the lightfastness improving liquid for ink jet recording absorbs the ultraviolet light which causes the decomposition reaction of the coloring material on the medium. Therefore, it is presumed that discoloration is unlikely to occur. In addition, by using a combination with a nonionic surfactant and optionally using a dispersant in combination, the dispersion stability of the organic ultraviolet absorber becomes extremely high. Therefore, even when used for a head having a small nozzle diameter for discharging a small drop, clogging does not occur over time. In addition, it is presumed that the organic ultraviolet absorber hardly coagulates on the paper, and the light fastness works in a direction to be further improved.

In addition, although the mechanism is still unknown, it also works to reduce ink bleeding on paper and improve image density. In addition, the wettability of the lightfastness improving liquid on paper increases, and the lightfastness improving liquid spreads, so that the amount of the organic ultraviolet absorber added can be reduced. In addition, since the lightfastness improving liquid for ink jet recording is rapidly absorbed into the paper,
It is presumed that the drying time is fast and that no color mixing occurs between the inks. In addition, since the ink does not contain an ultraviolet absorber, it is possible to prevent secondary obstacles such as aggregation due to interaction with the colorant during storage of the ink.

An ink jet recording ink set comprising the above ink jet recording ink and the ink jet recording lightfastness improving liquid is ejected from an orifice in accordance with a recording signal to perform recording on a recording material. It has been found that by using this, an image showing good light fastness with a sufficient image density and little discoloration is obtained, and that the drying property and the ejection reliability of the ink are good.

The ejection of the ink for ink jet recording and the lightfastness improving liquid for ink jet recording may be performed by either a thermal method in which a bubble is generated by a heater or a piezo method in which a piezoelectric element is used. In the case of the thermal method, by forming a single droplet by applying a plurality of pulses, the effect of increasing the ejection stability during continuous ejection can be obtained with a stable drop amount.

The ejection amount of the ink and the lightfastness improving liquid is preferably 30 ng or less per drop, and more preferably 0.1 to 20 ng, in order to reduce the roughness of the image. The lightfastness improving liquid for ink jet recording may be ejected to the entire surface of the recording medium, but it is preferable that the liquid is attached only to the image portion in consideration of curl / cuckle and printing time. (Amount of light-improving liquid for ink jet recording on recording medium) :( Fixed amount of ink for ink jet recording on recording medium) is preferably in the range of 0.2: 1 to 1.5: 1. The lightfastness improving liquid may be attached to the recording medium either before or after printing with the ink, but the lightfastness improving effect is more pronounced after printing.

As the recording medium, a commonly used recording medium can be used. For example, it is desirable to print on plain paper, plain paper for inkjet, glossy paper for inkjet, coated paper for inkjet, and glossy film for inkjet. In particular, it is unclear whether this is due to the effects of additives or surface structure contained in the paper, but glossy inkjet paper and inkjet coated paper are clearly more discolored and discolored than plain paper. In printing on such a recording medium, the ink set for inkjet recording of the present invention works more effectively.

[0053]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. (Example 1) The following components were sufficiently mixed, and 0.45 μm
The resulting mixture was filtered under pressure with a filter to prepare a cyan ink. CIDirect Blue 199 3 parts by weight Diethylene glycol 20 parts by weight Butyl carbitol 6 parts by weight Pure water 71 parts by weight

The following components were thoroughly mixed, and 0.45 μm
The mixture was filtered under pressure with a filter to prepare a magenta ink. CIAcid Red 37 3 parts by weight Glycerin 20 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 75 parts by weight

The following components were sufficiently mixed to form a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a yellow ink. CIDirect Yellow 142 2 parts by weight Thiodiglycol 5 parts by weight Ethylene glycol 15 parts by weight Triethylene glycol monobutyl ether 5 parts by weight Oxyethylene oleyl ether 0.5 parts by weight Pure water 72.5 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a black ink. CIDirect Black 168 3 parts by weight Propylene glycol 15 parts by weight Oxyethylene oxypropylene block polymer 1.5 parts by weight Urea 5 parts by weight Pure water 75.5 parts by weight

The following components were sufficiently mixed, and filtered under pressure through a 2 μm filter to prepare a light resistance improving liquid for ink jet recording. 2- (2'-Hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole 1 part by weight Dispersant 0.2 part by weight (styrene-acrylate-sodium acrylate copolymer) Ionic surfactant 1 part by weight (tetramethyldecinediol ethylene oxide adduct) Diethylene glycol 10 parts by weight Water 87.8 parts by weight

The above four colors of ink for ink jet recording and the light resistance improving liquid for ink jet recording were used as ink sets for ink jet recording.

Comparative Example 1 A four-color ink set was prepared in the same manner as in Example 1 except that the light resistance improving liquid for ink jet recording was omitted.

(Comparative Example 2)
0.5% by weight of 2-hydroxy-3-t-butyl-5-methyl-phenyl-5-chlorobenzotriazole was added, and pure water was added at 0.
A four-color ink set was prepared, which was the same except that the amount was reduced by 5% by weight and the lightfastness improving liquid for inkjet recording was omitted.

(Comparative Example 3) A light resistance improving solution for ink jet recording having the same composition as in Example 1 except that the nonionic surfactant was removed from the light resistance improving solution for ink jet recording and the amount was increased with pure water. It was prepared and used as an ink set for inkjet recording.

(Ink and Evaluation) (1) Surface tension: In an environment of 23 ° C. and 55% RH,
It measured using the Wilhelmy type surface tensiometer. (2) Viscosity: METT in an environment of 23 ° C and 55% RH
The measurement was performed using a LER260 Rheomat RM260.

(3) Conductivity: Measured using a conductivity meter (manufactured by DKK) in an environment of 23 ° C. and 55% RH. (4) pH: 23 ° C, 55% RH environment, Orio
n Measured using a pH meter.

(5) Light resistance evaluation test: 23 ° C., 55%
In an RH environment, using a prototype head with a resolution of 800 dpi, solid patches are printed on glossy paper RW-P2A4 (manufactured by SHARP) dedicated to inkjet, and optical density (OD),
L *, a * and b * were measured. After that, the printed matter is Suntest CPS
+ (Atlas) for about 50 hours, and the total irradiation light quantity is almost 100800 kJ / m ² (all wavelength range 300 ~
800 nm), and L *, a *,
b * (parameter in CIELAB color coordinates) was measured to determine ΔE due to light irradiation.

ΔE = √ [(L * _ini −L * _exp ) ² + (a * _ini −a *
_exp ) ² + (b * _ini − b * _exp ) ² ]

In the formula, ini is an abbreviation of initial and before irradiation, exp is e
Abbreviation of xposure means after irradiation. In addition, a test chart of a photographic image was printed in the same manner, and the unirradiated print sample and the irradiated print sample were visually visually evaluated for changes in color balance.

(6) Ink drop amount: 23 ° C., 55%
In a RH environment, using a prototype head with a resolution of 800 dpi, 1/4 tone (2035) at a frequency of 6 kHz.
× 128 dots) was ejected three times, the ink was received on a small piece of the ink absorber, the weight was measured, and the ejection weight of one drop was calculated.

(7) Drying time test: 23 ° C., 55% R
In the environment of H, using a prototype head with a resolution of 800 dpi, an image area ratio of 10 mm × 50 mm 100 to FX-L paper (manufactured by Fuji Xerox Co., Ltd.) as a typical plain paper.
% Of the solid image was printed, and the time from when the solid image was printed until when the droplets were visually invisible from the paper was measured.

(8) Image quality test: 23 ° C., 55% R
In the environment of H, a print test of 1 dot line and a solid image was performed on FX-L paper (manufactured by Fuji Xerox Co., Ltd.) as a typical plain paper using a prototype head having a resolution of 800 dpi. As the evaluation items, line bleeding and the uniformity of the edge of the solid image were examined, and the evaluation was performed according to the following criteria.

A) Line bleeding: ・: no bleeding, Δ: slight bleeding, x: bleeding bleeding in many parts b) Solid uniformity: ：: no disturbance; Δ: slight disturbance; ×: rattling and lack of smoothness.

(9) Clogging resistance test: The prepared ink and the lightfastness improving liquid were tested using a thermal ink jet printer with a resolution of 800 dpi for evaluation, at 23.degree.
The sample was left in the environment of H, and when the ejection was restarted, the standing time until image disturbance occurred was measured. The evaluation was performed according to the following criteria.・: 1 minute or more, Δ ・: 0.5 to less than 1 minute, ×: less than 0.5 minute.

(10) Storage stability test: The prepared ink and the light resistance improving liquid were stored at 60 ° C. and -20 ° C. for one month, and then printed using a thermal ink jet printer having a resolution of 800 dpi. The evaluation was performed according to the following criteria. ○ ・ ・ ・ ・ ・ ・ ・ No change in filter clogging before and after storage. No change in image density, Δ: Some filter clogging was observed after storage, but image density did not change, x: Filter clogging was severe after storage, and the image density was greatly reduced.

The results of the evaluation of Example 1 and Comparative Examples 1 to 3 are shown in Table 1 (where "C" indicates cyan,
"M" means magenta, "Y" means yellow, "K" means black ink, and "S" means lightfastness improving liquid). In Example 1, there was no problem with high light fastness, print quality, ink clogging, and ink storage stability.
In Comparative Examples 1 to 3, all of the required characteristics could not be satisfied.

[0074]

[Table 1]

Example 2 The following components were thoroughly mixed,
Pressure filtration was performed with a 0.45 μm filter to prepare a cyan ink. CIDirect Blue 307 3 parts by weight CIAcid Blue 9 0.3 parts by weight Glycerin 12 parts by weight Sulfolane 8 parts by weight Butyl carbitol 5 parts by weight Pure water 71.7 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a magenta ink. CIDirect Red 75 2.5 parts by weight Diethylene glycol 10 parts by weight Sulfolane 10 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 75.5 parts by weight

The following components were thoroughly mixed, and 0.45 μm
The mixture was filtered under pressure with a filter to prepare a yellow ink. CIDirect Yellow 132 2.0 parts by weight Diethylene glycol 10 parts by weight Thiodiglycol 10 parts by weight Oxyethylene oxypropylene block polymer 2.0 parts by weight Pure water 76 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a black ink. CIFood Black 2 4.0 parts by weight Ethylene glycol 20 parts by weight Hexyl carbitol 3 parts by weight Pure water 73 parts by weight

The following components were sufficiently mixed, and filtered under pressure through a 2 μm filter to prepare a light resistance improving liquid for ink jet recording. 2- (2'-human peroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole 1 part by weight Dispersant (acrylate ester-Na acrylate copolymer) 0.4 part by weight butyl carbitol 5 parts by weight Ethylene glycol 12 parts by weight Nonionic surfactant 0.2 parts by weight (oxyethyleneoxypropylene block polymer) Sulfolane 10 parts by weight Water 70.4 parts by weight

Using the above ink set for ink jet recording, the same evaluation as in Example 1 was performed. As a result, there was no problem in print image quality, clogging resistance and storage stability with high light fastness and no color balance shift. I understand.

Example 3 The following components were thoroughly mixed,
Pressure filtration was performed with a 0.45 μm filter to prepare a cyan ink. CIAcid Blue 9 1 part by weight CIDirect Blue 199 2 parts by weight Glycerin 10 parts by weight 2-pyrrolidone 10 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 75 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a magenta ink. CIAcid Red 52 0.5 parts by weight CIDirect Red 75 1.5 parts by weight Glycerin 10 parts by weight 2-pyrrolidone 10 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 76 parts by weight

The following components were thoroughly mixed, and 0.45 μm
The mixture was filtered under pressure with a filter to prepare a yellow ink. CIAcid Yellow 23 0.5 parts by weight CIDirect Yellow 144 1.5 parts by weight Glycerin 10 parts by weight 2-Pyrrolidone 10 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 76 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a black ink. X-34 (manufactured by BASF) 0.5 parts by weight CIDirect Black 195 2.5 parts by weight Glycerin 10 parts by weight 2-pyrrolidone 10 parts by weight Tetramethyldecinediol ethylene oxide adduct 2 parts by weight Pure water 75 parts by weight

The following components were sufficiently mixed, and filtered under pressure through a 2 μm filter to prepare a light resistance improving liquid for ink jet recording. 2-2-human peroxy-5-methylphenylbenzenetriazole 1.5 parts by weight Dispersant 0.2 parts by weight (styrene-methacrylic acid ester-sodium methacrylate copolymer) triethylene glycol monobutyl ether 5 parts by weight Nonionic surfactant 0.8 parts by weight (oxyethylene oxypropylene block polymer) Glycerin 15 parts by weight Water 77.5 parts by weight

Using the above ink set for ink jet recording, the same evaluation as in Example 1 was performed. As a result, there was no problem in print image quality, clogging resistance and storage stability with high light fastness and no color balance shift. I understand.

Example 4 The following components were thoroughly mixed,
Pressure filtration was performed with a 0.45 μm filter to prepare a cyan ink. CIDirect Blue 86 3.0 parts by weight Polyoxyethylene polyoxypropylene block polymer 1.5 parts by weight Urea 5 parts by weight Propylene glycol 20 parts by weight Pure water 70.5 parts by weight

The following components were thoroughly mixed, and 0.45 μm
The mixture was filtered under pressure with a filter to prepare a magenta ink. CIAcid Red 37 1.5 parts by weight CIDirect Violet 107 1.0 parts by weight Thiodiglycol 15 parts by weight Butyl carbitol 3 parts by weight Tetramethyldecinediol ethylene oxide adduct 0.4 parts by weight Pure water 79.1 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a yellow ink. CIDirect Yellow 86 2.5 parts by weight Tetramethyldecinediol ethylene oxide adduct 1.0 parts by weight (high molar adduct) Tetramethyldecinediol ethylene oxide adduct 1.0 parts by weight (low molar adduct) Glycerin 10 parts by weight Sulfolane 10 parts by weight Pure water 75.5 parts by weight

The following components were sufficiently mixed to form a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a black ink. CIFood Black 2 3.5 parts by weight Diethylene glycol 25 parts by weight Dipropylene glycol monobutyl ether 3 parts by weight Oxyethylene oleyl ether 0.5 parts by weight Sodium benzoate 3 parts by weight N, N-bis- (2-hydroxyethyl) -2- Aminoethanesulfonic acid 0.5 parts by weight NaOH 0.04 parts by weight Pure water 64.46 parts by weight

The following components were thoroughly mixed, and 0.45 μm
The mixture was filtered under pressure with a filter to prepare a light cyan ink. CIDirect Blue 86 0.7 parts by weight Polyoxyethylene polyoxypropylene block polymer 1.5 parts by weight Urea 5 parts by weight Diethylene glycol 20 parts by weight N-2-acetamidoiminodiacetic acid 0.3 parts by weight NaOH 0.04 parts by weight Pure water 72 .46 parts by weight

The following components were sufficiently mixed to obtain a mixture of 0.45 μm
The mixture was filtered under pressure with a filter to prepare a light-colored magenta ink. CIAcid Red 37 0.4 parts by weight CIDirect Violet 107 0.1 parts by weight Propylene glycol 15 parts by weight Butyl carbitol 3 parts by weight Tetramethyldecinediol ethylene oxide adduct 0.4 parts by weight Pure water 81.1 parts by weight

The following components were sufficiently mixed, and filtered under pressure with a 2 μm filter to prepare a light resistance improving liquid for ink jet recording. 2-Hydroxy-4-n-octoxybenzophenone 1 part by weight Dispersant 0.2 part by weight (sodium naphthalene sulfonate formalin condensate) Nonionic surfactant 1.0 part by weight (tetramethyldecine diol ethylene oxide adduct) ) Ethylene glycol 10 parts by weight Sulfolane 10 parts by weight Urea 4 parts by weight Pure water 73.8 parts by weight

The above ink set was put into a prototype ink jet printer, and an image was printed. An evaluation test was performed in the same manner as in Example 1. As a result, it was found that the print quality, clogging resistance, and storage stability had no problem with high light fastness and no color balance shift.

Example 5 The following components were thoroughly mixed,
The mixture was filtered under pressure through a 2 μm filter to prepare a lightfastness improving liquid for inkjet recording. p-octylphenyl salicylate 2 parts by weight Dispersant (styrene sulfonate Li salt polymer) 0.2 parts by weight Ethylene glycol 15 parts by weight Diethylene glycol monobutyl ether 4 parts by weight Nonionic surfactant 0.2 parts by weight (polyoxy Ethylene polyoxypropylene block polymer) Urea 5 parts by weight Pure water 73.6 parts by weight

With respect to cyan, magenta, yellow, and black inks, the same inks as in Example 1 were used, and an ink set was formed together with the above-mentioned light resistance improving liquid for ink jet recording. The above-mentioned ink set was put into a prototype inkjet printer, an image was printed, and an evaluation test was performed in the same manner as in Example 1. As a result, it was found that there was no problem in print image quality, clogging resistance, and storage stability with high light fastness and no color balance shift.

Example 6 The following components were thoroughly mixed,
The mixture was filtered under pressure through a 2 μm filter to prepare a lightfastness improving liquid for inkjet recording. 2,2-dihydroxy-4,4-dimethoxybenzophenone 0.5 part by weight Dispersant 0.2 part by weight (methyl acrylate-sodium acrylate copolymer) N-methyl-2-pyrrolidone 15 parts by weight Trimethylolpropane 5 parts by weight Part Nonionic surfactant 1 part by weight (tetramethyldecinediol ethylene oxide adduct) Pure water 78.3 parts by weight

With respect to cyan, magenta, yellow, and black inks, the same inks as in Example 2 were used, and an ink set was formed together with the above-mentioned light resistance improving liquid for ink jet recording. The above-mentioned ink set was put into a prototype inkjet printer, an image was printed, and an evaluation test was performed in the same manner as in Example 1. As a result, it was found that there was no problem in print image quality, clogging resistance, and storage stability with high light fastness and no color balance shift.

(Example 7) The following components were thoroughly mixed, and
The mixture was filtered under pressure through a 2 μm filter to prepare a lightfastness improving liquid for inkjet recording. 2- (2'-Hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole 1.5 parts by weight Dispersant 0.5 parts by weight (Naphthalenesulfonic acid sodium formalin condensate) Nonionic surfactant 0.1 part by weight (tetramethyldecine diol ethylene oxide adduct) Nonionic surfactant 0.5 part by weight (oxyethylene stearyl ether) diethylene glycol 15 parts by weight Pure water 82.4 parts by weight

With respect to the cyan, magenta, yellow, and black inks, the same inks as in Example 3 were used, and an ink set was formed together with the above-mentioned light resistance improving liquid for ink jet recording. The above-mentioned ink set was put into a prototype inkjet printer, an image was printed, and an evaluation test was performed in the same manner as in Example 1. As a result, it was found that there was no problem in print image quality, clogging resistance, and storage stability, with high light fastness and no color balance shift.

Example 8 The following components were thoroughly mixed,
The mixture was filtered under pressure through a 2 μm filter to prepare a lightfastness improving liquid for inkjet recording. Phenyl salicylate 2.0 parts by weight Dispersant (Na styrene sulfonate polymer) 0.4 parts by weight Diethylene glycol monobutyl ether 5 parts by weight Glycerin 15 parts by weight Nonionic surfactant 0.3 parts by weight (polyoxyethylene oleyl ether) 77.3 parts by weight of pure water

With respect to the cyan, magenta, yellow, and black inks, the same inks as in Example 3 were used, and an ink set was prepared together with the above-described light-resistance improving liquid for ink jet recording. The above-mentioned ink set was put into a prototype inkjet printer, an image was printed, and an evaluation test was performed in the same manner as in Example 1. As a result, it was found that there was no problem in print image quality, clogging resistance, and storage stability with high light fastness and no color balance shift.

[0103]

According to the present invention, there is provided an ink-jet recording ink set and an ink-jet recording method which can obtain a sufficient image density, exhibit good light fastness, and have good ink drying properties and reliability regarding ejection. be able to.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mihoko Tani 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Akihiko Nakajo 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72 ) Inventor Hiromi Nagai 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Taiga Iinuma 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 1600 Takematsu Fuji Xerox Co., Ltd. (72) Inventor Hoharu Endo 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Takeshi Hashimoto 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Terms (reference) 2C056 EA05 EA13 FD20 HA42 HA44 2H086 BA02 BA52 BA53 BA55 BA59 4J039 AE07 BC09 BC12 BC13 BC35 BC50 BC54 BC55 BE01 BE04 BE05 BE12 EA10 EA15 EA16 EA17 EA19 EA35 EA42 EA44 GA24

Claims (2)

[Claims] 1. An ink jet recording ink containing water, a water-soluble organic solvent and a colorant; and a light fastness improving liquid for ink jet recording containing water, an organic ultraviolet absorber and a nonionic surfactant. Ink set for inkjet recording. 2. An ink jet recording ink containing water, a water-soluble organic solvent, and a coloring material; and a light fastness improving liquid for ink jet recording containing water, an organic ultraviolet absorber and a nonionic surfactant as a recording signal. An ink jet recording method in which recording is performed on a recording material by discharging from an orifice in response to the recording.