JPH10195357A - Recording ink and ink jet printer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording means in which an ink to be used for full-color recording is specified by use of spectral characteristics, which is one of physical properties, and hence a full-color recording of high quality is performed at a low cost, by utilizing a recording ink comprising a colorant and a solvent dissolving the same which has a value in a specific range for a proportion of the integral of the absorbance thereof in a specific range of wave length. SOLUTION: Use is made of an ink in the analysis of which with a spectrophotometer a/b value is as follows, wherein a represents an integral of the absorbance in the range of λ±25nm wherein λnm is the wave length at which the maximum absorbance is observed and b represents an integral of the absorbance between 400 and 700nm: a/b >=0.40 when λnm (the wave length at which the maximum absorbance is observed) is less than 500nm, a/b>=0.45 when λnm is 500 to 600nm, and a/b >=0.40 when λnm is 600nm or more. This recording ink has high lightness and high saturation of color and, in full-color recording, the decrease in lightness and saturation of color upon color mixing can be reduced by using this ink, so that matching of primary colors can be carried out with ease. This also enables the reduction of the time, expense and cost required to the development of an ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for full-color recording, and more particularly to a recording ink used in an ink-jet type full-color printer used for a terminal printer for a personal computer.

[0002]

2. Description of the Related Art As a means for performing recording on a recording material such as paper, a solution in which various dyes or pigments are dissolved or dispersed in a solvent such as water or an organic solvent (hereinafter, such a solution is referred to as ink). ) Is applied to or impregnated with the recording material to be colored.

[0003] For example, an ink jet recording method in which minute ink droplets are made to fly and adhere to a recording material is one of the recording means. When full-color printing is performed by such a printing means, a method of mixing and coloring three primary colors of ink of magenta, cyan, and yellow on a recording material is generally used. Therefore, the color of the recorded image depends on the color of the ink of the three primary colors to be mixed. Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 54-89811, it is possible to limit the wavelength at which a specific rate of the absorbance among the spectral characteristics of each of the three primary colors is limited.
As disclosed in Japanese Patent Application Publication No. 04-2004, by using a specific dye for the inks of the three primary colors, the colors of the three primary colors are specified, and the hue, lightness, and saturation of the recorded image are improved. And had

[0004]

The above-described color mixing method is a subtractive color mixing method. For example, ink jet recording is performed by adhering a coloring material in the ink onto a recording material, but in a recording image of full-color recording, three primary color materials, which are different coloring materials, are printed on the recording material. Full-color recording is achieved by overlapping and mixing. Since the color mixture is a superposition of color materials of different colors, the wavelength range of the absorbed light increases, and the perceived color of the recording is darker and less vivid than the color of the recording of each of the three primary colors alone. It will be.

It is ideal that each of the three primary colors does not have the hues of the other primary colors. However, in actual color materials, the hues of the other primary colors are always included, although the degree is different. . Therefore, in addition to the hue that produces pure color by mixing colors, there are more hue parts that produce extra color. This also contributes to a decrease in brightness and saturation.

[0006] Since the lightness and saturation of the ink colors are reduced due to color mixing, in full-color printing, the inks of the three primary colors have different lightness and lightness when recorded independently.
Unless a material having high saturation is used, it is impossible to prevent a decrease in recording quality due to a decrease in lightness and saturation after color mixing. In addition, since the recording is a full-color recording, the three primary colors need to match each other.

Conventionally, there has been no simple method for obtaining a color material that makes good full-color printing a good color, or a simple method for matching three primary colors, and trial production and printing of inks until a desired good full-color printing is obtained. The color measurement cycle was repeated. This has led to a prolonged development of the ink and an increase in cost, which has led to an increase in the cost of products using this ink.

Accordingly, the present invention has been made to solve such a problem, and an ink for performing full-color recording is specified by using a spectral characteristic which is one of physical characteristics. , The quality of full color recording is good,
It is an object of the present invention to provide an inexpensive recording means such as an ink jet printer.

[0009]

The recording ink of the present invention is a recording ink comprising at least a coloring material such as a dye or pigment for coloring a recording material and a solvent dissolving the coloring material. When the ink was analyzed with a spectrophotometer, the wavelength showing the maximum absorbance was λ nm, and λ-25n
The integrated absorbance in the wavelength range from m to λ + 25 nm is a, 40
When the absorbance integrated value in the wavelength range from 0 nm to 700 nm is b, a / b ≧ 0.40 when the wavelength showing the maximum absorbance is 500 nm or less, and when the wavelength showing the maximum absorbance is from 500 nm to 600 nm. Is a / b ≧ 0.4
5, and when the wavelength showing the maximum absorbance is 600 nm or more, a / b ≧ 0.40.

According to the present invention, the saturation and lightness of the colors at the time of recording are high, and the decrease in the lightness and saturation of the color of the recorded image due to the color mixture at the time of full color printing can be reduced. Quality can be improved.

Further, according to the present invention, good hue of ink for full color recording and matching of three primary color inks can be easily performed, and the time required for ink development can be reduced.
The cost can be reduced, and the cost of a product using the recording means, for example, a printer using an ink jet recording method does not increase.

Regarding the absorbances a and b of the ink, when the wavelength showing the maximum absorbance is 500 nm or less, a
/B≧0.50 and the wavelength showing the maximum absorbance is 500
When it is in the range of nm to 600 nm, it is more preferable that a / b ≧ 0.65, whereby the saturation and brightness of the color of the ink can be further increased, and the recording quality can be improved.

The ink jet printer according to the present invention includes a first nozzle for discharging a first recording ink which satisfies at least a / b ≧ 0.40 and has a wavelength showing a maximum absorbance of 500 nm or less; a / b ≧ 0.45, and the wavelength showing the maximum absorbance is 500 nm to 600 nm
And a third nozzle for ejecting a third ink that satisfies a / b ≧ 0.40 and has a wavelength of 600 nm or more that satisfies a / b ≧ 0.40. A nozzle is provided. Since the recording inks ejected from the nozzles are adjusted in advance so that the color saturation and lightness do not decrease when they are superimposed, good full-color recording can be performed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to examples, and the effects will be illustrated together.

The present invention relates to a recording ink comprising a coloring material such as a dye or pigment for coloring a recording material and a solvent for dissolving the coloring material. Adjustable surfactants, preservatives, pH adjusters and the like can be added.

The content of the coloring material used for coloring in the present invention with respect to the ink is determined by the type of the ink component, the characteristics required for the ink, and the like. , Preferably in the range of 0.5 to 10 wt%.

When the ink is used as the coloring material in the above-described amount, the ink is analyzed by a spectrophotometer.
When the wavelength indicating the maximum absorbance is 500 nm or less, a / b ≧ 0.40, and the wavelength indicating the maximum absorbance is 50 nm.
A / b ≧ 0.45 when the wavelength is 0 nm to 600 nm, and a / b ≧ 0.40 when the wavelength showing the maximum absorbance is 600 nm or more, alone or in combination. It is desirable to use. For example, C.I. I. Ac
id Red-287, C.I. I. Acid Red-9
2, C.I. I. Acid Yellow-23, C.I. I.
Direct Yellow-142, C.I. I. Aci
d Blue-9, C.I. I. Direct Blue-
199 and the like, but are not limited thereto.

As the solvent component in the ink of the present invention,
Various organic solvents having a moisturizing effect can be used alone or in combination to ensure the moisturizing properties of the ink. Examples thereof include water-soluble organic solvents having a low vapor pressure, such as polyalkylene glycols such as polypropylene glycol, glycols such as ethylene glycol, and lower alkyl ethers of polyhydric alcohols such as erylene glycol monomethyl ether. The amount of the organic solvent to be added is preferably in the range of 1 to 50% by weight based on the total weight of the ink, and more preferably in the range of 1 to 30% by weight in view of the ink viscosity, evaporability and the like.

[0019]

EXAMPLES After mixing and dissolving the compositions shown in Table 1 with sufficient stirring, they were filtered using a membrane filter having a hole diameter of 0.8 μm to prepare inks of Examples of the present invention. Color recording was performed using these inks. All formulations are "parts by weight".

Table 1 also shows comparative examples produced in the same manner.

[0021]

[Table 1]

Each of the inks of Examples 1 to 6 and Comparative Examples 1 to 3 was diluted 1000 times with pure water, and the absorbance of the spectral characteristics was measured under the measurement conditions shown in Table 2.

[0023]

[Table 2]

In the color recording for determining the print quality of the inks of the present embodiment and the comparative example, PPC paper of neutral paper, register paper of acidic paper, 45 kg high quality paper, 70 k
g Recording was performed on each recording medium of high-quality paper using our MJ-510C which is an inkjet printer having an on-demand type recording head as recording means.

The color of each recorded matter is measured by a spectrophotometer (CM-501).
i, manufactured by Minolta Co.) for each sheet under standard light D65, and the average of the colors of the recorded matter on the four sheets was taken as the color of recording with each ink. The color obtained by the measurement is JI
This is based on the L * a * b * color system defined by SZ8729, and the degree of vividness “saturation”, which is one of the color elements, is calculated using the hue components a * and b *. a * ×
a * + b * × b *). Based on the color obtained by the measurement, the color name of the obtained recording was obtained from the color name of the object color specified in JIS Z8102.

In Examples 1 to 6 and Comparative Examples 1 to 3, 400
Wavelength [lambda] (nm) showing the maximum peak of the absorbance in the spectral characteristics at -700 nm, from [lambda] -25 nm to [lambda] +25.
Table 3 shows the ratio of the integrated value of the absorbance a in the wavelength region of nm to the integrated value of the absorbance b in the wavelength region of 400 to 700 nm, L *, a *, b * and the saturation, which are the color components of the recording of each ink alone. Show.

[0027]

[Table 3]

Examples 1 to 6 and Comparative Example 1 were applied to a recording medium.
Each of the three inks is used in two colors, "red" using magenta and yellow inks, "green" using yellow and cyan inks, and "blue" using magenta and cyan inks. Was recorded in three colors. Table 4 shows the obtained three colors and the color names defined in JIS Z8102.

[0029]

[Table 4]

According to the color names of the object colors defined in JIS Z8102, the colors of the obtained recordings are “bright yellowish red” in the color recording using the first to sixth embodiments.
“Green” or “yellowish green”, “brilliant bluish purple” or “purple blue” are all bright and highly saturated colors, and each ink is an excellent primary color liquid for color recording. It is a thing.

On the other hand, the colors of the color records according to Comparative Examples 1 to 3 are “yellowish red”, “dull yellowish green”,
It was a dark, dull, low-saturation color, “purple purple”.

[0032]

As described above, according to the present invention, with respect to the color of ink for full-color recording, a good color ink can be obtained, and the quality of the color at the time of recording can be judged at the stage of ink preparation. Therefore, in the development of ink, the cycle of trial production, recording, and color measurement of ink can be minimized, the time and cost required for ink development can be reduced, and the cost of recording means using the ink can be reduced. Therefore, an inexpensive recording means such as an ink jet printer can be provided.

Claims (4)

[Claims] 1. A recording ink comprising at least a coloring material such as a dye or a pigment for coloring a recording material and a solvent dissolving the coloring material, when the ink is analyzed by a spectrophotometer, the maximum value is obtained. The wavelength indicating the absorbance is λ nm,
When the integrated value of the absorbance in the wavelength range of λ-25 nm to λ + 25 nm is a, and the integrated value of the absorbance in the wavelength range of 400 nm to 700 nm is b, a / b ≧ 0.40 when the wavelength showing the maximum absorbance is 500 nm or less. A / b when the wavelength showing the maximum absorbance is between 500 nm and 600 nm.
≧ 0.45 and the wavelength showing the maximum absorbance is 600 nm
In the above case, a / b ≧ 0.40, the recording ink. 2. The recording ink according to claim 1, wherein
When the ink is analyzed with a spectral altimeter, a / b ≧ 0.50 when the wavelength showing the maximum absorbance is 500 nm or less for the absorbance integrated values a and b described in the preceding section, indicating the maximum absorbance. A / b ≧ 0.65 when the wavelength is from 500 nm to 600 nm. 3. An ink jet printer using the recording liquid according to claim 1, wherein at least a / b ≧ 0.4.
A first nozzle for discharging a first recording ink that satisfies 0 and has a wavelength indicating a maximum absorbance of 500 nm or less;
a / b ≧ 0.45 and the wavelength showing the maximum absorbance is 5
A second nozzle for ejecting a second recording ink having a wavelength of 00 nm to 600 nm, and a second nozzle for ejecting a third ink which satisfies a / b ≧ 0.40 and has a maximum absorbance of 600 nm or more. An ink jet printer comprising a third nozzle. 4. The ink-jet printer according to claim 3, wherein the ratio of the integrated absorbances a and b of the first recording liquid is a / b ≧ 0.50, and the integrated absorbance of the second recording liquid. An ink jet printer, wherein the ratio of the values a and b satisfies a / b ≧ 0.6.