JP2002038063A - Ink set containing white ink and ink jet recording method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set containing a white ink and capable of reproducing a vivid color image without being influenced by the ground color of a recording medium even when color printing is made on a colored paper or a white recording medium having a yellowish ground color on the surface on which printing is made, and a method of recording using the ink set. SOLUTION: The ink set for a color image contains a white ink used for the treatment of the substrate of a recording medium on which an image is formed, or for the treatment for color correction depending upon the ground color of a recording medium. The manner of delivering the white ink is regulated depending upon the ground color of a recording medium. The white ink is delivered over the whole region of a recording medium in which an image can be formed, thus making the ground color of the recording medium white. Alternatively, the region of a recording medium in which an image is to be formed is detected beforehand, and the white ink is delivered into the region. Alternatively, the recording medium is subjected to a treatment for color correction with the white ink, and an image is then formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink set containing white ink in an ink set for ink jet recording for a color image and an ink jet recording method using the same.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, in order to print a high-definition color image, yellow,
An ink set combining color inks such as magenta, light magenta, cyan, and light cyan is used. The vividness of a color image obtained using such an ink jet recording apparatus using a conventional ink set is affected by the ground color of the printing surface of the recording medium. Therefore, in order to reproduce a vivid color image, recording media such as inkjet dedicated paper and inkjet dedicated glossy paper having a high whiteness of the ground color of the surface to be printed are generally used.

[0003]

However, using such an ink jet recording apparatus using the conventional ink set, a color is applied to a white recording medium, such as recycled paper or government-made postcard, in which the ground color of the surface to be printed is yellowish. If you print,
Compared to the case where color printing is performed on the above-described inkjet-only paper, inkjet-only glossy paper, or the like, the image is printed in a yellowish color, so that there is a problem that a colorful color image cannot be reproduced. Therefore, in order to reproduce a colorful color image with an ink jet recording apparatus using a conventional ink set, an expensive recording medium such as an ink jet dedicated paper or an ink jet dedicated glossy paper needs to be used. Further, when reproducing white color with the conventional ink set, the ground color of the recording medium is used as white, so that white color cannot be reproduced on a recording medium having a ground color other than white, such as colored paper. In addition, there is a problem in that when reproducing other colors, the image is affected by the ground color of colored paper or the like and is reproduced in a color different from the original color.

The present invention has been made in view of the above-mentioned conventional problems, and is intended to be applied to a case where color printing is performed on a recording medium or colored paper having a yellowish ground on a printing surface. It is another object of the present invention to provide an ink set including a white ink capable of reproducing a colorful color image without being affected by the ground color of a recording medium, and an ink jet recording method using the same.

[0005]

That is, an ink set containing white ink according to the present invention is an ink set for ink jet recording for a color image, which is used for a base treatment of a recording medium for forming an image. Or an ink set for inkjet recording for a color image, wherein the ink set includes a white ink used for a complementary color process according to a ground color of a recording medium on which an image is formed. (Claim 2), and
The above object is achieved by "the white ink is composed of pigment ink" (claim 3).

The ink jet recording method using an ink set containing a white ink according to the present invention is "using a white ink for a base treatment of a recording medium on which an image is formed" (Claim 4). Controlling how the white ink is applied in accordance with the ground color of the recording medium (Claim 5); by applying the white ink to the entire surface of the image forming area of the recording medium, Setting the ground color to white (Claim 6); detecting an image forming area of the recording medium in advance and applying the white ink to the image forming area (Claim 7); The image forming apparatus is controlled so that image formation is performed after a predetermined time (claim 8). Alternatively, a white ink is used for a complementary color process according to a ground color of a recording medium on which an image is formed (claim 9). By having these features, the above object is achieved.

According to the present invention, the ink set includes a white ink used for a base treatment of a recording medium on which an image is to be formed. A color image printed using this ink set reproduces a vivid color image without being affected by the ground color of the recording medium. Alternatively, by including a white ink used for a complementary color process corresponding to the ground color of a recording medium on which an image is formed, the color of the surface to be printed such as colored paper is originally the same as that for a recording medium other than white. A color image is reproduced with a color balance (claim 2). further,
When a pigment ink is used as the white ink, the pigment ink generally has an opaque property, so that the background color of the recording medium is hidden and a more vivid color image is reproduced (claim 3).

Further, by applying an ink jet recording method using a white ink for a base treatment of a recording medium on which an image is formed to a printing method of an ink jet recording apparatus, a white color in which the ground color of a printing surface is yellowish is obtained. When color printing is performed on a medium, a colorful color image is reproduced without being affected by the ground color of the recording medium.
Further, the amount of white ink to be used can be adjusted to an appropriate amount by controlling the method of ejecting the white ink according to the ground color of the recording medium. In addition, a vibrant color image can be reproduced by a simple control device by ejecting the white ink over the entire area of the recording medium where an image can be formed. Further, by detecting the image forming area of the recording medium in advance and ejecting white ink into the image forming area, the processing area of the white ink can be adjusted corresponding to the image forming area. In addition, by controlling the image formation after a certain period of time after the white ink is injected, it is possible to prevent color mixture and bleeding between the white ink and other color inks. In addition, by using a white ink for a complementary color process corresponding to the ground color of a recording medium on which an image is formed, a color image can be formed on a recording medium having a color other than white, such as colored paper, with the same color balance as the original. It can be reproduced (claim 9).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An ink set including a white ink according to the present invention includes a white ink used for a base treatment of a recording medium on which an image is formed. Alternatively, it contains white ink used for complementary color processing according to the ground color of a recording medium on which an image is formed. Further, a pigment is preferably used as a coloring material of the white ink.

Further, the ink jet recording method according to the present invention uses the above-described white ink for a base treatment of a recording medium on which an image is formed, and controls a method of ejecting the white ink according to the ground color of the recording medium. is there. A specific control method is to control how white ink is ejected according to the ground color of the recording medium. By ejecting the white ink over the entire area of the image forming area of the recording medium, the white ink is ejected. It is characterized in that the ground color is white, or an image forming area of the recording medium is detected in advance, and white ink is injected into the image forming area. Alternatively, white ink is used in a complementary color process corresponding to the ground color of a recording medium on which an image is formed, and the method of ejecting the white ink is controlled.

Next, preferred embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments, and may be appropriately modified within the scope of the matters specifying the invention. Is what you can do.

The present embodiment includes a color ink set including six colors of yellow ink, magenta ink, light magenta ink, cyan ink, light cyan ink, and white ink, and an ink set including black ink.

The coloring material of the white ink is a pigment and contains one or more of the following. Examples of the coloring agent of the white ink include zinc, lead, barium, titanium, oxides such as antimony, and white inorganic pigments such as sulfates and carbonates, among which anatase-type titanium dioxide, rutile-type titanium dioxide, Titanium dioxide having a crystal structure such as brookite-type titanium dioxide can be suitably used. In order to improve dispersibility, the particle size of the colorant is preferably set to 2.
0 μm or less, more preferably 0.2 μm or less. Further, the addition amount is preferably 1 to 50% by weight, more preferably 2 to 30% by weight.

The white ink contains at least water together with the pigment. Further, it preferably contains an organic solvent. The organic solvent is preferably a low-boiling organic solvent, and preferred examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol and iso-butanol. And pentanol. Particularly, a monohydric alcohol is preferable. In order to shorten the ink drying time, the content is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight.

It is preferable that the white ink further contains a wetting agent to prevent clogging of the nozzles of the recording head. 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, thioglycol, hexyleneglycol, glycerin, trimethylolethane, trimethylolpropane, urea, 2-pyrrolidone,
1,3-dimethyl-2-imidazole, imidazole,
N-methyl-2-pyrrolidone and the like, and further,
Saccharides can also be included, and examples of saccharides include monosaccharides, disaccharide oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose. , Galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose and the like. Here, the polysaccharide means a sugar in a broad sense, and is used to include a substance widely existing in nature such as cellulose. The amount of these wetting agents added is 0.5
A range of from about 40% by weight to about 20% by weight is suitable.

Further, the white ink preferably contains a penetrating agent such as an alkyl ether derivative of a polyhydric alcohol. Specific examples of the alkyl ether derivative of the 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. Triethylene glycol mono-n
Preference is given to using butyl ether and mixtures containing it. The addition amount of the alkyl ether derivative of these polyhydric alcohols is 0.5 to 20% by weight based on the dispersion to be produced.
It is preferably in the range of 3 to 15% by weight.

The amount of the pigment to be added to the white ink 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 pigment.
A range of 〜10% by weight is preferred.

When a pigment is used as a colorant, the pigment is preferably added as a pigment dispersion obtained by dispersing the pigment in an aqueous medium with a dispersant or a surfactant. As the dispersant, any one which has already been generally used as a dispersant for dispersing a pigment can be used. For example, a polymer compound and a surfactant can be used, and more preferably a high-dispersion agent is used. It is a molecular compound. It is obvious to those skilled in the art that a polymer compound can be preferably used as a dispersant, but it is generally considered that dispersion is obtained when a repulsive force occurs that can repel the attractive force generated between pigment particles. . It is said that the repulsion is caused by a surface potential provided by an electric double layer generated on the surface of the particles, and by steric hindrance caused by an adsorption layer adsorbed on the surface of the particles and spreading from the surface. When these repulsions are greater (dense) and further away from the particle surface, a stable dispersion can be obtained. It is generally said that a more stable dispersion can be obtained with a polymer compound having a molecular weight ranging from thousands to tens of thousands than a surfactant having a molecular weight ranging from tens to hundreds.

Preferred examples of the polymer dispersant include natural polymers, and specific examples thereof include proteins such as glue, gelatin, casein and albumin, natural rubbers such as gum arabic and tragacanth, and savonin. Glucosides, alginic acid and propylene glycol alginate, alginic acid derivatives such as triethanolamine alginate, ammonium alginate and sodium alginate, and cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose and ethylhydroxyethylcellulose.

Preferred examples of the polymer dispersant include synthetic polymers, such as polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, and vinyl acetate. Acrylic resins such as acrylic ester copolymers, acrylic acid-alkyl acrylate copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid-alkyl acrylate copolymers, styrene-α-methyl Styrene-acrylic resin such as styrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid, styrene-maleic anhydride, vinylnaphthalene-acrylic acid copolymer Polymer, vinyl acetate And a vinyl acetate-fatty acid vinyl ethylene copolymer, a vinyl acetate maleate ester copolymer, and salts thereof.

Of 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 particularly preferable. Examples of the above salts include diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, triethanolamine,
Salts with diethanolamine, aminomethylpropanol morpholine and the like can be mentioned. These copolymers preferably have a weight average molecular weight of about 3,000 to 30,000, more preferably about 5,000 to 15,000. The amount of the dispersant added is not particularly limited, but is preferably in the range of 0.06 to 3, more preferably 0.125 to 3, with respect to the pigment 1.

Examples of preferred surfactants include:
Anionic surfactants (eg, sodium dodecylbenzenesulfonate, sodium laurate, ammonium salts of polyoxyethylene alkyl ether sulfate, etc.), nonionic surfactants (eg, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, Polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc.), and these can be used alone or in combination of two or more.

Further, it may contain acetylene glycol represented by the following formula (1).

[0024]

Embedded image

In the above formula (1), R ¹ , R ² , R
^3, and the alkyl group having 1 to 6 carbon atoms represented by R ⁴ is preferably an alkyl of 1 to 4 carbon atoms, more preferably a methyl group. Further, n and m are such that their sum is 0
Is an integer of up to 30. Preferred examples of the acetylene glycol compound represented by the formula (1) include 2,4,
7,9 tetramethyl-5-decyne-4,7-diol,
3,6-dimethyl-4-octyne-3,6-diol,
And 3,5-dimethyl-1-hexyn-3-ol. In addition, a commercially available product can be used as the compound of the formula (1). For example, Surfynol 104, 82, 465, 485 or TG manufactured by Nissin Chemical Co., Ltd. can be used. The amount of the acetylene glycol compound added is preferably about 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on the dispersion to be produced.

Further, a pH adjuster can be added to the white ink for the purpose of further improving the dispersion stability of the colorant. It is preferable to adjust the pH of the white ink in the range of 5 to 12, more preferably in the range of 6 to 10. p
Specific examples of the H adjustor include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, lithium carbonate, sodium phosphate, potassium phosphate, lithium phosphate, and diphosphate. Potassium hydrogen, dipotassium hydrogen phosphate, sodium oxalate, potassium oxalate, lithium oxalate, sodium borate, sodium tetraborate, potassium metal such as potassium hydrogen phthalate, potassium hydrogen tartrate, ammonia, methylamine, ethylamine , Diethylamine,
Amines such as tris (hydroxymethyl) aminomethane hydrochloride, triethanolamine, morpholine and propanolamine are preferred.

Further, the white ink may contain a viscosity modifier, an antioxidant, an ultraviolet absorber, an antiseptic / antifungal agent and the like.

When a pigment is used as a colorant, the white ink is preferably prepared by first dispersing the pigment in water to which the above-mentioned dispersant or surfactant is added, thereby preparing a pigment dispersion. The pigment dispersion is mixed with an aqueous solution obtained by adding the various additives described above to water or water, if necessary, and the pigment is added to water, if necessary, May be mixed and dispersed in an aqueous solution obtained by adding the various additives described above.

[Other Inks] Other inks use the following dyes as coloring materials. In addition, other inks contain at least water with a dye, preferably contain an organic solvent, a dispersant, a surfactant, a penetrant, a wetting agent, a pH adjuster, and a preservative.
It is similar to the case of the above-described white ink that a fungicide or the like is preferably added. The preparation of other inks is the same as the method of preparing a white ink when the above-mentioned dye is used as a coloring material.

Dyes used in other inks include the following dyes.・ As a dye used for magenta ink, for example, CI 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, 211,21
2, 214, 218,221, 223, 224, 225, 226, 227, 232, 23
3, 240, 241, 242, 243, 247, CI Acid Red 35, 4
2, 52, 57, 62, 80, 82, 111, 114, 118, 119, 127,12
8, 131, 143, 151, 154, 158, 249, 254, 257, 261,26
3, 266, 289,299, 301,305, 336, 337, 361, 396, 397,
CI Reactive Red 3, 13, 17, 19, 21, 22, 23, 2
4, 29, 35, 37, 40,41, 43, 45,49, 55, CI Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29,
35, 36, 38, 39, 45, 46 and the like. -As a dye used in the yellow ink, for example, 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, 1
06, 108, 109, 110, 130, 132, 142, 144, 161, 163, but CI Direct Yellow 86 and / or 132 is preferably used. -As a dye used for cyan ink, for example, CI Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 8
0, 84, 86, 87, 90, 98, 106, 108, 109, 151, 156, 15
8,159,160,168,189,192,193,194,199,200,20
1, 202, 203, 207, 211, 213, 214, 218, 225, 229, 23
6,237,244,248,249,251,252,264,270,280,28
8, 289 and 291 can be mentioned, but it is preferable to use CI Direct Blue 199. -As a dye used in black ink, for example, CI Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 9
1,94,97,108,112,113,114,117,118,121,12
2, 125, 132, 146, 154, 166, 168, 173, 199.

Next, the ink jet recording method of the present embodiment will be described in detail with reference to the drawings. Figure 1
1 is a perspective view showing a cartridge of a color ink set according to one embodiment of the present invention. FIG. 2 is a perspective view illustrating a configuration of a carriage that holds a color ink set and a black ink cartridge according to an embodiment of the present invention. FIG. 3 is a schematic configuration diagram of an inkjet printer that performs an inkjet recording method according to an embodiment of the present invention.

An ink jet printer to which a color ink cartridge is applied will be described with reference to FIG. As shown in FIG. 3, the printer 30 has a mechanism for transporting the paper P by a paper feed remotor 302, a mechanism for causing the carriage 20 to reciprocate while facing the platen 301 by a carriage motor 305, and is mounted on the carriage 20. And a control circuit 310 that controls the ejection of ink and the formation of dots by driving the print head 303, and the control circuit 310 that controls the exchange of signals with the paper feed motor 302, the carriage motor 305, the print head 303, and the operation panel 311. It is configured.

The mechanism for transporting the sheet P as a recording medium is as follows.
A gear train for transmitting the rotation of the paper feed remotor 302 not only to the platen 301 but also to a paper transport roller (not shown) is provided. The mechanism for reciprocating the carriage 20 is provided in parallel with the axis of the platen 301, and
A carriage 305, a pulley 308 for extending an endless drive belt 306, a position detection sensor 309 for detecting the origin position of the carriage 20, and the like. Have been.

Although the control system is not shown,
The control circuit provided in the printer is, for example, a well-known CP.
Character generator (CG) storing U, P-ROM and RAM storing programs, dot matrix of characters
It is configured as an arithmetic and logic operation circuit centered on the above, etc., and in addition to this, an I / F dedicated circuit dedicated to interfacing with an external motor or the like, and connected to the I / F dedicated circuit to drive the print head 303 And a motor drive circuit for driving the paper feed motor 302 and the carriage motor 305.

Next, the color ink cartridge 10 and the carriage 2 on which the color ink cartridge 10 is mounted
0 will be described. As shown in FIG. 2, the carriage 20 includes a black ink cartridge 307 (see FIG. 3).
And a color ink cartridge 10 (see FIG. 1), and includes, for example, a partition plate 201 that partitions both cartridges so that they can be mounted. The print head 303 below the carriage has a total of seven ink discharge heads. The bottom of the carriage 20 has an inlet pipe 20 for guiding ink from the ink tank to each color head.
2 to 208 are provided upright. When the black ink cartridge 307 and the color ink cartridge 10 are mounted on the carriage 20 from above, the introduction pipes 202 to 208 are pushed into the connection holes provided in each cartridge.

The color ink cartridge 10 shown in FIG. 1 contains two types of magenta and cyan inks, two types of dark and light, and a total of six types of inks of yellow and white. The color ink cartridge 10 is formed in a rectangular parallelepiped shape as a whole.
Ink storage chamber 10 that stores yellow and white inks
1 to 106 are sectioned.

In the color ink cartridge 10, both ends of the frame 107 are formed inside the outer wall 110 and protrude from ink supply ports (not shown) at both ends. Therefore, the end face of the frame 107 has a sufficient area. For example, the tape 107 for sealing which seals the ink supply port at the time of storage does not protrude from the outside wall 110 at both ends, and all the ink It can be attached so as to simultaneously seal the supply port.

When the tape 108 is applied, the air inside the frame 107 is allowed to flow into an air escape portion formed inside the frame 107, and then is allowed to escape from the cutout provided in the upper green of the frame 107. It has been. Therefore, tape 1
08 can be adhered to the end face of the frame 107 without difficulty. In addition, on the upper part of the color ink cartridge 10,
A lid 111 that seals the opening of the color ink cartridge 10 can be fitted.

As described above, using an ink jet printer provided with the ink set including the white ink described above, the method of ejecting the white ink is controlled according to the ground color of the recording medium. In this control method, the ground color of the recording medium is set to white by ejecting the image forming white ink over the entire surface of the recording medium. Alternatively, the ground color of the image forming area is set to white by ejecting white ink into the image forming area of the recording medium. Preferably, after the white ink is injected, control is performed such that an image is formed with another color ink after a certain period of time until the white ink dries. This can prevent color mixture and bleeding between the white ink and another color ink. Further, it can also be used for complementary color processing according to the ground color of the recording medium on which the image is formed, whereby the image to be actually printed can be printed after correcting the color balance according to the ground color.

[0040]

Next, the present invention will be described in detail with reference to examples of the present invention, but the present invention is not limited to these examples.

A color ink set for ink jet recording comprising the following white ink, yellow ink, cyan ink, magenta ink, light cyan ink, and light magenta ink was used.

[White ink] Anatase titanium dioxide 1.5% by weight Styrene-acrylic acid copolymer (dispersant) Molecular weight = 7000 4.0% by weight Diethylene glycol 5.0% by weight Glycerin 10% by weight Triethylene glycol mono-n-butyl ether 8.0% by weight Surfy NOL 465 1.0% by weight Potassium hydroxide 0.2% by weight Pure water Remainder All of the above components were added to Minimill 100 (Eiger Machinery Inc.,
Bensenbille IL) and milled at 3000 rpm for 2 hours. The resulting dispersion was filtered through a 5 μm membrane filter to obtain an ink composition containing 2% by weight of a pigment.

[Each Ink] The following coloring agents were used in place of the dispersing agent in place of the coloring agent in the white ink. The above milling and filtration operations are not performed.・ Light magenta ink: CI Direct Red 227 0.8% by weight ・ Magenta ink: CI Direct Red 227 3.0% by weight ・ Yellow ink: CI Direct Yellow 86 2.5% by weight ・ Light cyan ink: CI Direct Blue 199 0.8% by weight ・ Cyan ink: CI Direct Blue 199 3.0% by weight

Example 1 As a base treatment for a recording medium described below, white ink was previously applied to the entire surface, and evaluation was performed by the following test method (1) image quality evaluation immediately after image formation (2) color reproducibility test. Inkjet recording paper Recycled paper Government-made postcard Colored paper

(Example 2) As a base treatment for a recording medium described below, white ink was previously applied only to an area where an image was actually formed, and the following test methods (1) image quality evaluation immediately after image formation (2) color reproducibility test Was evaluated. Inkjet recording paper Recycled paper Government-made postcard Colored paper

(Example 3) As a base treatment and a complementary color treatment, white ink is ejected together with a color ink according to the ground color of the recording medium described below, and the following test methods (1) Image quality evaluation immediately after image formation (2) Color The evaluation was performed in a reproducibility test. Inkjet recording paper Recycled paper Government-made postcard Colored paper

(Comparative Example) A color ink set for ink jet recording comprising a yellow ink, a cyan ink, a magenta ink, a light cyan ink, and a light magenta having the same composition as in Example 1 (a conventional ink set having no white ink) was used. An image was formed on the following recording medium, and evaluated by the following test method (1) Image quality evaluation immediately after image formation (2) Color reproducibility test. Inkjet recording paper Recycled paper Government-made postcard Colored paper

The above Examples and Comparative Examples were evaluated by the following methods, and the results are shown. ◇ Test method (1) Evaluation of image quality immediately after image formation Ink cartridges manufactured in Examples and Comparative Examples
Examples 1 to 3 were performed using a black ink cartridge IC5BK05 (trade name of Seiko Epson Corporation).
And the image name portrait of high-definition color digital standard image data (ISO / JIS-SCID) on the recording medium by the recording method of the comparative example (sample number 1, image identification symbol N1)
Was printed. Printing was performed using an inkjet printer PM-800C (trade name of Seiko Epson Corporation) as a printer. Immediately after image formation, the sharpness of the image was visually confirmed and evaluated according to the following evaluation criteria. A: Vivid image is reproduced. B: The effect of ground color is seen only in the area where no image is formed. C: The effect of ground color is seen on the image.

(2) Color Reproducibility Test Using the ink cartridges prepared in Examples and Comparative Examples and the black ink cartridge IC5BK05 (trade name of Seiko Epson Corporation),
The solid printing of black (Bk), yellow (Y), magenta (M), and cyan (C) was performed by the inkjet printer PM-800C using the recording methods of Examples 1 to 3 and the comparative example. The area was determined from the * b * chromaticity diagram, and the area obtained by the recording method of the comparative example was taken as 100% and evaluated according to the following evaluation criteria. A: The area ratio is 120% or more B: The area ratio is 100% or more and less than 120% C: The area ratio is less than 100%

Test results (1) Image quality evaluation results immediately after image formation

[0051]

[Table 1]

(2) Result of color reproducibility test

[Table 2]

As shown in the above results, Examples 1 and 2 in which the base processing was performed with white ink and Example 3 in which the base processing and the complementary color processing were performed were compared with the comparative example in which the base processing was not performed. As a result, good results were obtained in the image quality test and color reproducibility test immediately after image formation on a recording medium (recycled paper, government-made postcard) or colored paper with a yellow ground color.

[0054]

According to the ink set including the white ink according to the present invention, the ground color of the printing surface is yellowish white by including the white ink used for the base treatment of the recording medium for forming an image in the ink set. A color image printed on this recording medium using this ink set can reproduce a vivid color image without being affected by the ground color of the recording medium (claim 1). Further, by including a white ink used for a complementary color process corresponding to the ground color of a recording medium on which an image is formed, the ink set is used for a white recording medium or a colored paper in which the ground color of a printing surface is yellowish. The color image printed in this way can reproduce a vivid color image with the same color balance as the original without being affected by the ground color of the recording medium. Further, when a pigment ink is used as the white ink, the pigment ink generally has an opaque property, so that the ground color of the recording medium is hidden, and a more vivid color image can be reproduced (claim 3).

According to the ink jet recording method using the ink set containing the white ink according to the present invention, the ink jet recording method using the white ink for the base treatment of the recording medium on which the image is formed is different from the printing method of the ink jet recording apparatus. By applying the method, when color printing is performed on a white recording medium whose background color is yellowish, a colorful color image can be reproduced without being affected by the background color of the recording medium. 4). Further, the amount of white ink to be used can be adjusted to an appropriate amount by controlling the method of ejecting the white ink according to the ground color of the recording medium. In addition, a vibrant color image can be reproduced by a simple control device by ejecting the white ink over the entire area of the recording medium where an image can be formed. Further, by detecting the image forming area of the recording medium in advance and ejecting white ink into the image forming area, the processing area of the white ink can be adjusted corresponding to the image forming area. Further, by controlling the image formation after a certain period of time after the white ink is applied, it is possible to prevent color mixture and bleeding of the white ink with other color inks. Claim 8) In addition, by using white ink for a complementary color process corresponding to the ground color of a recording medium on which an image is formed, the same color balance can be obtained even on a recording medium other than white, such as colored paper, in which the color of the printing surface is other than white. To reproduce colorful images (claim 9)

As described above, by performing color printing with the ink set containing the white ink of the present invention and the ink jet recording apparatus to which the ink jet recording method using the same is applied, yellowed recording paper such as recycled paper, government-made postcard, or the like is obtained. Even when color printing is performed on colored paper, a colorful color image can be printed as when printing is performed on an expensive recording medium such as inkjet-only paper or inkjet glossy paper.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cartridge of a color ink set according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a carriage that holds a color ink set and a black ink cartridge according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an ink jet printer that performs a recording method according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 color ink cartridge 20 carriage 30 printer 101 to 106 ink storage chamber 107 frame 108 tape 110 outer wall 111 lid 201 partition plate 202 to 208 introduction tube 301 platen 302 paper feed motor 303 print head 304 sliding shaft 305 carriage motor 306 drive Belt 307 Black ink cartridge 308 Pulley 309 Position detection sensor 310 Control circuit 311 Operation panel

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B41J 3/04 101A F term (reference) 2C056 EA09 EA11 EB29 EC07 EC28 EC36 EC72 ED07 EE03 EE18 FA10 FC02 KC01 KC13 2H086 BA04 BA55 4J039 BA13 BA16 BA18 BA30 BA31 BA34 BA35 BE01 CA06 EA18 EA29 EA47 GA24

Claims (9)

[Claims] 1. An ink set for inkjet recording for a color image, comprising a white ink used for a base treatment of a recording medium on which an image is formed. 2. An ink set for inkjet recording for a color image, comprising a white ink used for a complementary color process according to a ground color of a recording medium on which an image is formed. 3. The ink set including the white ink according to claim 1, wherein the white ink is a pigment ink. 4. An ink jet recording method using a white ink for a base treatment of a recording medium on which an image is formed. 5. The ink jet recording method according to claim 4, wherein a method of ejecting the white ink is controlled according to a ground color of the recording medium. 6. The ink-jet recording method according to claim 5, wherein the ground color of the recording medium is set to white by ejecting the white ink onto the entire surface of the image forming area of the recording medium. 7. An image forming area of a recording medium is detected in advance.
6. The ink jet recording method according to claim 5, wherein the ground color of the image forming area is set to white by ejecting the white ink into the image forming area. 8. The ink-jet recording method according to claim 4, wherein control is performed such that an image is formed after a predetermined time has elapsed after the white ink has been ejected. 9. An ink jet recording method using a white ink for a complementary color process according to a ground color of a recording medium on which an image is formed.