JPH10158560A - Ink set for color ink jet recording and recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject ink set capable of providing a sharp and clear image by preventing mixing color bleeding by influx of the ink by regulating inorganicity (hydrophilicity)/organicity (hydrophobicity) of dyes in each color ink used in combination. SOLUTION: This ink set is the one for color ink jet color recording capable of forming a color image on a material to be recorded by using two or more kinds selected from plural aqueous color inks containing a block ink, in each of which a value of inorganicity/organicity (I/O value) of the dye is regulated to 1-3. The content of the coloring agent comprising the dye in the ink composition is preferably 1-10wt.% in terms of solid in the ink composition. Polyfunctional alcohols is preferable as a solvent in a water-soluble organic solvent used because of having a large dry-preventing effect for preventing defect of ejection. A penetrating agent such as diethylene glycol monobuthyl ether, or a surfactant is preferably added to each of the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording ink set and a recording method for a color ink jet printer.

[0002]

2. Description of the Related Art In general, a color printer performs printing by superimposing each color of yellow, magenta, and cyan. Therefore, in the case of ink jet recording, there is a serious problem that inks, which are liquids, mix with each other or flow out. I have.

[0003] Conventionally, in order to solve the above problems,
For example, as in JP-A-60-197778, the surface tension of the recording liquid of each color for forming a color image is in the range of 30 to 60 dyn / cm at 20 ° C., and the surface tension of the recording liquid of each color is uniform. A method has been proposed in which the use of such a material makes the fixing time and the degree of bleeding of the recording liquid of each color on the recording material equal, thereby suppressing the deterioration of the color image. However, the method using the recording ink does not reduce the degree of bleeding of the recorded matter, and cannot be a means for improving image deterioration. In addition, the recording ink has a problem that the print quality is inferior when a black recorded matter is compared with a monochrome printer.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording ink set which can prevent color mixture bleeding due to ink flowing between black ink and color ink and can provide a sharp and clear color image. It is in.

[0005]

In order to achieve the above-mentioned object, the present invention provides a recording material using two or more inks selected from a plurality of aqueous color inks including a black ink by an ink jet recording method. In the method of forming a color image, the inorganic / organic value (I / O value) of the dye contained in each color ink was adjusted to be in the range of 1.0 to 3.0. It is characterized in that two or more types of color inks are used in combination to form a mixed color portion on a recording material.

In the present invention, the dye in each color ink (including the black ink here) used in combination to form a color image is converted into an organic (hydrophobic) and inorganic (hydrophilic) dye. Selection is based on the balance characteristic of gender. And adjusting the inks so that the balance characteristics of each dye are similar to each other;
By adjusting the balance characteristics of the respective dyes to the balance characteristics of the recording material, the above-mentioned object is achieved without the occurrence of separation of dyes of different colors in the recording material.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a value obtained from the calculation specified below is used as a standard as a balance property between organic (hydrophobic) and inorganic (hydrophilic) properties of a dye to be used.

Method for Determining Inorganic / Organic Value of Dye The overall properties of an organic compound are represented by a combination of inorganic and organic properties as shown in the following formula.

[0009]

(Equation 1)

[0010] The hydrocarbon has an organic value of 20 for one carbon atom, indicating that it is completely organic. From this and the inorganic values of the various inorganic groups, the inorganic / organic value (I / O value) can be calculated for each dye. Dyes having an equal ratio of inorganic to organic are considered to exhibit similar properties.

According to the knowledge obtained by the present inventors as a result of intensive studies, the inorganic / organic values (I / O) of the dyes in the respective color inks used in combination on the same recording material.
Value), and found that bleeding hardly occurs in practical use when any one of the following six items has a relationship between them.

(1) The I / O value of the dye is at least 1.0
To 3.0. (2) The difference between the I / O values of the dyes is at least within 0.6. (3) The difference between the IO value of the ink water obtained by removing the dye from the ink and the IO value of the dye is at least 0.8 or more. (4) The difference between the I / O value of the dye and the I / O value of the recording material is at least within 0.3. (5) When the recording material is paper (cellulose), the I /
The O value is at least in the range of 2.3 to 3.1.

That is, when the I / O values of the dye and the paper are close to each other, a strong affinity (adsorption force) acts between the two to prevent color bleeding. Conversely, the I / O value of the dye is
When the value is close to the / O value, the dye exerts a strong affinity (adsorption force) on the ink water side and causes bleeding.

Further, the inorganic / organic value (I / O value)
It has been found that the definition of す る improves water resistance in addition to bleed.

It was also found that this I / O value had a very close correlation with the transfer rate Rf value determined by the paper chromatography method. Therefore, the I / O of the dye
If the value cannot be determined by calculation, the dye can be adjusted based on the Rf value determined from the dye chromatographic method.

When the color ink used in the present invention is prepared and prepared, for example, cyan, magenta, yellow,
Various water-soluble dyes that exhibit black color are used. Among them, the dyes listed below are particularly suitable in the present invention. In addition, each numerical value in parentheses added to the dyes exemplified below indicates the I / O value obtained by the above method. In calculating the I / O value, it was calculated based on Table 1.1, "Inorganic base table", page 13 of "Organic Conceptual Diagram-Basics and Applications-" by Yoshio Koda.

Cyan dye

[0018]

Embedded image

(2.40)

[0020]

Embedded image

(1.30)

[0022]

Embedded image

(0.93)

[0024]

Embedded image

(1.62)

[0026]

Embedded image

(2.33)

[0028]

Embedded image

(1.60)

[0030]

Embedded image

(1.57)

[0032]

Embedded image

(0.94)

[0034]

Embedded image

(1.67)

[0036]

Embedded image

(1.50) Magenta dye

[0038]

Embedded image

(1.32)

[0040]

Embedded image

(2.31)

[0042]

Embedded image

(2.97)

[0044]

Embedded image

(3.08)

[0046]

Embedded image

(2.10)

[0048]

Embedded image

(1.87) Yellow dye

[0050]

Embedded image

(2.42)

[0052]

Embedded image

(1.94)

[0054]

Embedded image

(1.60)

[0056]

Embedded image

(2.02)

[0058]

Embedded image

(1.79)

[0060]

Embedded image

(1.34)

[0062]

Embedded image

(1.89)

[0064]

Embedded image

(2.76) Black dye

[0066]

Embedded image

(1.63)

[0068]

Embedded image

(1.63)

[0070]

Embedded image

(1.42)

[0072]

Embedded image

(1.57)

[0074]

Embedded image

(1.41)

[0076]

Embedded image

(2.32)

[0078]

Embedded image

(2.07)

[0080]

Embedded image

(2.63) The cyan, magenta, yellow, and black inks used in the ink set for color ink jet recording of the present invention are suitable for the above-mentioned colorants such as dyes and water or various organic solvents. It consists of various additives.

The content of these colorants in the ink composition is preferably in the range of 1 to 10% by weight in terms of solid content in consideration of print density, clogging, ejection characteristics and the like of the recorded matter.

The solvent used in the ink jet recording ink of the present invention is a water-soluble organic solvent other than ion-exchanged water, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol. , Sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol and the like, alkyl alcohol ethers having 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketones and keto alcohols such as acetone and diacetone alcohol Ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol;
Ethylene glycol, propylene glycol, 1, 2,
Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as 6-hexanetriol, thiodiglycol, hexylene glycol; glycerin; ethylene glycol methyl ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl ( Or lower alkyl ethers of other alcohols such as ethyl) ether.

Among the above water-soluble organic solvents, polyhydric alcohols are formed by evaporating water in the ink jet recording ink.
This is preferable because the effect as a drying inhibitor for preventing ejection failure due to nozzle clogging due to deposition of the recording agent is large.

These water-soluble organic solvents can be used alone or in combination of two or more.

Further, cyan, magenta, yellow, and the like used in the ink set for color ink jet recording of the present invention.
In order to satisfy both print quality and penetrability, a penetrant such as diethylene glycol monobutyl ether or triethylene glycol monobutyl ether, or Olfin STG or Olfin E1010 is used for each black ink.
It is necessary to add a surfactant such as a penetrant. This increases the permeability of the ink into the paper and is effective in preventing bleeding.

In addition to the above, recording inks used in the ink set for color ink jet recording of the present invention include conventionally known dispersants, surfactants, viscosity adjusters, surface tension adjusters, specific resistance adjusters, pH adjusters, and the like. An antioxidant, a fungicide, a chelating agent and the like can be added as needed.

The content of these various additives in the ink composition varies depending on the purpose, but excessive amounts may cause foaming, precipitation, deterioration of storage stability, etc.
It is desirable to use in the range of wt%.

[0089]

Hereinafter, the ink set for color inkjet recording of the present invention will be described with reference to specific examples and comparative examples of the present invention.

(Examples 1 to 9) The basic ink compositions of the respective colors shown in Table 1 were combined with the dyes of the respective colors shown in Table 2, and the compositions of the respective colors were individually stirred and then filtered using a filter. The cyan ink, magenta ink, yellow ink and black ink of Examples 1 to 8 of the present invention were prepared. In Example 9, the I / O value shown in Table 3 was 1.
Inks were prepared by combining the dyes of each color shown in Table 2 with the basic ink composition of No. 5. The following two items were evaluated. The evaluation results are shown in Table 2.

[0091]

[Table 1]

[0092]

[Table 2]

[0093]

[Table 3]

[Test 1] Characters of 7 colors and 10
0% duty printing Using the adjusted ink compositions of cyan, magenta, yellow, and black, a predetermined printing is performed using a 360 dpi, 48 nozzle on-demand ink jet recording apparatus which is a prototype equipped with a piezo vibrator. In accordance with the image signal, the recording medium is ejected onto recording materials having different I / O values listed in Table 4 to print seven colors (cyan, magenta, yellow, red, green, blue, and black) ( Character, solid). The obtained color printing was good in character printing quality, with no color unevenness in solid portions, and high quality was realized.

[0095]

[Table 4]

The I / O values of the recording materials shown in Table 4 were obtained by multiplying the I / O values of the respective constituent materials of each paper by the compounding amount, and the total of each was defined as the I / O value of the paper. XERO # 7 in Table 4
The calculation method will be described below taking the case of X (recycled paper) as an example. Table 5 shows the constituent materials of XEROX (recycled paper) paper, the I / O value of each material, and the compounding fee.

[0097]

[Table 5]

I / O value of the regenerated balm × the compounding amount of the I / O value of the spherical cellulose × the compounding amount of the cationic starch × the compounding amount of the I / O value of the cationic starch × the I / O value of the filler (light calcium) × compounding amount + alkyl kentener dimer I / O value × compounding amount = 3.01 × 0.5 + 2.
83 × 0.2 + 2.00 × 0.1 + 2.50 × 0.1 + 1.00 × 0.1 = 2.62 [Test 2] Bleed due to mixed color of black ink and yellow ink (image by contact) The yellow ink was printed at 100% duty on the XEROX paper shown in FIG. 4, and the bleeding of the image due to the contact by the mixed color of the black ink and the yellow ink was visually observed on the sample in which the character was printed with the black ink on the yellow ink. Was evaluated as follows. X: The image is remarkably blurred and the image is deteriorated. Δ: Bleeding is noticeable. ：: Slight bleeding is observed, but there is no effect on the entire image. A: Bleeding is not noticeable.

In Examples 1 to 5, the I / O value of the dye is at least in the range of 1.0 to 3.0, whereby the color bleed of the dye is suppressed.

In Example 6, the I / O values of the dye were in the range of 1.3 to 1.9, and the color bleed of the dye was suppressed because the I / O values were uniform within this range.

In the seventh embodiment, the I / O value of the recording material is 2.2.
When the I / O value of the dye is in the range of 1.90 to 2.70 when the value is 0 to 2.40, it indicates that color bleeding can be suppressed. The I / O values of the dyes are in the range from 2.02 to 2.42.

In Example 8, the recording material was paper (cellulose).
, The I / O value of the paper is 2.83, so the I / O value of the dye
A value in the range of at least 2.3 to 3.1 indicates that color bleed is suppressed. The I / O values of the dyes are in the range from 2.32 to 3.08.

In Example 9, the I / O value of the ink water having the composition shown below was 1.50. When this ink water was used, the I / O value of the dye and the I / O value of the ink water were Is 0.
It indicates that the presence of 8 or more suppresses color bleed. The I / O value of the dye is from 2.32 to 3.08
In the range.

In all of the ink compositions of Examples 1 to 9, a penetrant or a surfactant is blended.

(Comparative Examples 1 and 2) In the following comparative examples, images were formed in the same manner as in the examples, and the occurrence of color bleed was visually observed. As a result, in each case, occurrence of color unevenness (color bleed) was observed in the mixed color portion.

(Comparative Example 1) Color bleeding occurred when a dye having an I / O value of 1.0 or less was used in the basic ink composition shown in Table 1.

(Comparative Example 2) Color bleeding occurred when a dye having an I / O value of 3.0 or more was used in the basic ink composition shown in Table 1.

The recording inks of Comparative Examples 1 and 2 were evaluated in the same manner as in Tests 1 and 2, and the results are shown in Table 6.

[0109]

[Table 6]

[0110]

According to the ink set for color ink jet recording of the present invention, by defining the inorganic / organic value (I / O value) of the color ink and the recording material, it is possible to obtain the black ink and the color ink. For both colors, a sharp and clear color image can be obtained without flowing of ink when mixing colors on recording paper and without bleeding.

Claims (9)

[Claims] 1. An ink set for color inkjet recording used in a method for forming a color image on a recording material using two or more types of inks selected from a plurality of aqueous color inks including a black ink, An ink set for color inkjet recording, wherein an inorganic / organic value (I / O value) of a dye contained in each color ink is at least a value in a range of 1.0 to 3.0. 2. The method according to claim 1, wherein the difference between the I / O values of the dyes is at least 0.6.
2. The ink set for color inkjet recording according to claim 1, wherein: 3. An ink water I obtained by removing a dye from the ink.
2. The ink set for color inkjet recording according to claim 1, wherein the difference between the / O value and the I / O value of the dye is at least 0.8 or more. 4. An ink set for color inkjet recording, wherein the difference between the I / O value of the dye and the I / O value of the recording material is at least within 0.3. 5. The color ink jet recording according to claim 4, wherein when the recording material is paper (cellulose), the I / O value of the dye is at least in the range of 2.3 to 3.1. Ink set. 6. An ink composition for ink jet recording, comprising at least water, a dye, a hydrophilic high-boiling low-volatile solvent, a polyhydric alcohol lower alkyl ether, and acetylene glycol represented by the following formula (I). 2. The composition according to claim 1, wherein the lower alkyl ether comprises 7 to 12% by weight of a polyhydric alcohol and 0.5 to 1.2% by weight of an acetylene glycol represented by the following formula (I). Ink set for color inkjet recording. Embedded image (Where R ¹ , R ² , R ³ , and R ⁴ each independently represent an alkyl group having 1 to 6 carbon atoms, and n + m is 0 to 3)
Represents 0. ) 7. The color according to claim 6, wherein the color contains 7 to 10% by weight of a lower alkyl ether of a polyhydric alcohol and 0.5 to 2% by weight of the acetylene glycol represented by the formula (I). Ink set for inkjet recording. 8. The ink set for color ink jet recording according to claim 6, wherein the amount of the hydrophilic high-boiling low-volatile solvent is 50% by weight or more based on the lower alkyl ether of the polyhydric alcohol. 9. A recording method for recording on a recording medium using the ink set for color inkjet recording according to claim 1.