JPH04248879A - Ink for ink jet recording - Google Patents

Abstract

PURPOSE:To produce the subject quick-drying ink for ink jet recording, capable of having a stable quality of printed letters independently of paper qualities and free from color mixture in color printing by mixing a specified silicone- based solvent with a colorant insoluble in this solvent in a specified ratio. CONSTITUTION:The objective ink containing (A) 2-95wt.% silicone-based solvent having 100-250 deg.C (preferably 130-200 deg.C) boiling point, preferably <=-20 deg.C flow- point, <=25dyne/cm (25 deg.C) surface tension, <=10mPa sec (25 deg.C) viscosity and <=20mmHg (25 deg.C) vapor pressure and (B) a colorant composed of an organic pigment insoluble in the component (A), carbon black, a dyestuff, etc.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention deforms a pressure generating member immersed in ink, changes the pressure of ink existing inside a nozzle forming substrate, and prints by ejecting ink droplets from a nozzle. The present invention relates to inkjet recording ink used in inkjet printers.

0002

2. Description of the Related Art Inkjet recording is excellent in quietness during recording and high-speed printing performance. Conventionally, liquid ink compositions based on water or organic solvents have been used as ink compositions for inkjet.

0003

[Problems to be Solved by the Invention] However, with conventional ink compositions, the transfer characteristics to the transfer object differ depending on the transfer object, so stable printing quality cannot be obtained and the transfer objects that can be printed are limited. There was a problem. In addition, for safety reasons, it is necessary to use a non-volatile solvent or a solvent with a flash point of 60°C or higher, and it takes several tens of seconds or more to dry, which slows down the printing speed and makes it difficult to print color images. In some cases, a plurality of inks transferred onto the paper at the same time mix together (hereinafter referred to as color mixing), making it impossible to express a clear image.

[0004] Therefore, the object of the present invention is to provide a method that has high compatibility with various types of transfer materials, provides stable print quality and quick drying properties for various types of transfer materials, and is capable of simultaneously transferring color images onto paper. To provide an inkjet recording ink capable of obtaining a clear image without color mixing of a plurality of inks.

[0005]

[Means for Solving the Problems] The inkjet recording ink of the present invention has a boiling point of at least 100°C to 250°C.
It is characterized by containing 2 to 95 wt (%) of a silicone solvent of °C and a coloring material insoluble in the solvent, and the coloring material is an organic pigment or carbon black, and furthermore, it is a dye. Features.

[0006]

[Function] With the inkjet recording ink of the present invention having the above characteristics, good print quality can be obtained regardless of the paper quality.
Further, sufficient printing durability can be obtained within a few seconds after printing, and a clear image without color mixture can be obtained in a color image.

[0007]

[Examples] The present invention will be specifically explained below with reference to Examples and Comparative Examples.

Examples of the structural formula of the silicone solvent that can be used in the inkjet recording ink of the present invention are shown below, but the invention is not limited thereto.

[0009]

[Chemical formula 1]

In addition to the above, methylphenyl silicone oil containing a phenylsiloxy group, methylhydrogen silicone oil containing a hydrogen siloxy group, or atomic groups such as a trifluoropropyl group, a chlorophenyl group, a nitrile group, a carboxyl group, an amino group, etc. Furthermore, there are modified silicone oils of the copolymer type with polyoxyalkylene, higher alcohols, fatty acids, etc., but the invention is not limited thereto.

The physical properties of the silicone solvent that can be used in the inkjet recording ink of the present invention include a boiling point of 100°C to 250°C, more preferably 130°C to 200°C, and a pour point of -20°C or lower. , surface tension 2
5 dyne/cm (at 25°C) or less, viscosity 10 mP
a second (at25°C) or less, steaming at 20mmHg (at2
5°C) or less is preferable.

Further, it is preferable that the flash point is either none or 60°C or higher, but there is no problem as long as the flash point of the ink is 60°C or higher.

FIG. 1 shows the configuration of an inkjet printer head on which transfer experiments of this ink were conducted. As shown in FIG. 1, the ink 2 is pressurized by the displacement of the pressure generating member 9.
is discharged from the nozzle 4 formed on the nozzle forming substrate 1,
The ink droplets 3 collide with the object to be transferred and form dots.

[0014] This principle has the advantage that the ink ejection speed can be improved and there is a wide degree of freedom in the types of ink that can be used.

FIG. 2 schematically shows the concept of the principle of penetrating fixation of the inkjet recording ink of the present invention.

As shown in FIG. 2, the silicone solvent 8 in the ink 5 that collides with the transfer target 7 instantaneously permeates into the transfer target due to capillary action, forming dots 6.

During this silicone-based solvent penetration phenomenon, it is desirable that the coloring material in the ink remains and adheres to the transfer target to form the dots 6, but even if it partially penetrates, the print quality will be affected. There is no problem as long as it does not affect the sharpness of edges.

Dyes that can be used in the inkjet recording ink of the present invention include nitro and nitroso dyes, stilbene dyes, pyrazolone dyes, thiazole dyes, azo dyes, pyrazolone dyes, carbonium dyes, azine dyes, oxazine dyes, and thiazine dyes. , sulfur dye,
Nigrosine dyes, pyridine and quinoline dyes, quinone imine dyes, indigo dyes, indigoid dyes, anthraquinone dyes, phthalocyanine dyes, cyanine dyes, C.I.
I. Direct yellow 1, 8, 11, 12, 24
, 26, 27, 28, 33, 39, 44, 50, 58,
85, 86, 87, 89, 98, C. I. Acid Yellow 1, 3, 7, 11, 17, 19, 23, 25,
29, 38, 44, 79, 127, 144, C. I. Basic Yellow 1, 2, 11, 34, C. I. Direct Red 1, 2, 4, 9, 11, 13, 17
, 20, 23, 24, 28, 31, 33, 37, 39,
44, 46, 62, 63, 75, 79, 80, 81, 8
3, 84, 89, 95, 99, 113, 197, 201
, 218, 220, 224, 225, 226, 227,
228, 229, 230, 231, C. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 26, 2
7, 35, 37, 42, 52, 82, 85, 87, 89
, 92, 97, 106, 111, 114, 115, 11
8, 134, 158, 186, 249, 254, 289
,C. I. Basic red 1, 2, 9, 12, 1
4, 17, 18, 37, C. I. direct blue
1, 7, 9, 22, 23, 25, 29, 40, 41, 4
3, 45, 78, 80, 82, 92, 127, 249,
C. I. Acid blue 1, 7, 9, 22, 23,
25, 29, 40, 41, 43, 45, 78, 80, 8
2, 92, 127, 24, C. I. basic blue
1, 3, 5, 7, 9, 22, 24, 25, 26, 28
, 29, C. I. Direct black 2, 7, 19
, 22, 24, 32, 38, 51, 56, 63, 71,
74, 75, 77, 108, 154C. I. Acid black 1, 2, 7, 24, 26, 29, 31, 44
, 48, 50, 52, 94C. I. Basic black 2,8C. I. Solvent Yellow 1, 2, 3
, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14,
15, 16, 17, 19, 21, 26, 27, 29, 3
0, 35, 39, 40, 46, 49, 50, 51, 56
, 61, 80, 86, 87, 89, 96C. I. Solvent red 1, 2, 3, 8, 16, 17, 18, 1
9, 20, 22, 23, 24, 25, 26, 27, 30
, 49, 52, 59, 60, 63, 67, 68, 81,
82, 84, 100, 121C. I. Solvent blue 2, 6, 11, 12, 15, 20, 25, 30, 3
1, 32, 35, 36, 55, 58, 71, 72, 73
,C. I. Solvent black 3, 5, 7, 10,
11, 12, 13, 22, 23C. I. Disperse Yellow 1, 3, 4, 7, 8, 31, C. I. Dispersed Red 1, 4, 5, 7, 11, 12, C. I
．． Disperse Blue 1, 3, 5, 6, 7, 27,
C. I. Disperse black 1, 2, 10, 26
, 27, 28, etc.

In the present invention, the above-mentioned dyes are not dissolved in a solvent, but are used after being dispersed.

Pigments that can be used in the inkjet recording ink of the present invention are not particularly limited.
For example, for monochrome use, carbon blacks such as furnace black, lamp black, acetylene black, and channel black, simple metals such as copper and iron, orthonitroaniline black, and the like can be used.

Furthermore, for color use, first yellow 10G, disazo yellow AAMX, disazo yellow AAOT, disazo yellow AAOA, yellow iron oxide,
Disazo Yellow HR, Orthonitroaniline Orange, Dinitroaniline Orange, Vulcan Orange, Toluidine Red, Chlorinated Para Red, Brilliant Fast Scar Red, Naphthol Red 23, Pyrazolone Red, Barium Red 2B, Calcium Red 2B,
Strontium Red 2B, Manganese Red 2B, Barium Lysome Red, Pigment Scarlet 3B Lake, Lake Bordeaux 10B, Ansosine 3B Lake, Ansosine 5B Lake, Rhodamine 6G Lake, Eosin Lake, Japanese Garla, Faftol Red FGR, Rhodamine B Lake, Methyl Bayer Red Lake, Dioxazine Violet, Basic Blue 5B Lake, Basic Blue 6G Lake, Fast Sky Blue, Alkaline Blue R Toner, Peacock Blue Lake, Deep Blue, Ultramarine, Reflex Blue 2G, Reflex Blue R,
Brilliant green lake, diamond green thioflavin lake, phthalocyanine green G, green gold, phthalocyanine green Y, iron oxide powder, rust, zinc white, titanium oxide, calcium carbonate, clay,
Barium sulfate, alumina white, aluminum powder, bronze powder, daylight fluorescent pigment, pearl pigment, naphthol carmine FB, naphthol red M, permanent carmine FB, fast yellow G, disazo yellow AA
A, Disazo Orange PMP, Lake Red C, Brilliant Carmine 6B, Phthalocyanine Blue, Quinacridone Red, Dioxane Violet, Victoria Pure Blue, Alkali Blue G toner, etc. can be used.

[0022] As the colorant, it is also possible to use a mixture of a dye and a pigment or carbon black.

Solvents other than silicone solvents that can be used in the inkjet recording ink of the present invention include aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, and ethers. solvents, acetal solvents, ketone solvents, ester solvents, polyhydric alcohol solvents and their derivatives, fatty acid solvents, phenol solvents, nitrogen compound solvents, fluorine solvents, water, etc., all of which can be used alone or A mixture of two or more types can be used.

However, for safety reasons, the flash point must be 60°C or higher.

[0025] Also, a solvent such as water, which has a high surface tension when used alone, is mixed with a low surface tension solvent. Alternatively, it is desirable to lower the surface tension by mixing with a surfactant.

Materials that can be added to the inkjet recording ink of the present invention to obtain effects include surfactants, dispersants, soluble resins, and resin emulsions. Surfactants and dispersants have effects such as lowering the surface tension of ink and solubilizing dyes.

[0027] Also, soluble resins, resin emulsions, etc. are effective in improving the printing durability of printed matter or adjusting the permeation area.

Table 1 shows ink composition examples of Examples 1 to 3 of the black ink for inkjet recording of the present invention.

[0029] The fluorine-based solvent contained in the inkjet recording ink of the present invention is preferably 2 to 95 wt%; if it is less than this, sufficient permeability cannot be obtained, and if it exceeds this range, the degree of inertness is improved. However, there is a problem that sufficient dispersion stability of the coloring material cannot be ensured.

[0030]

[Table 1]

Si solvent A: Technocare FRV manufactured by Toshiba
B: Technocare FRS manufactured by Toshiba
C: Silicone oil KF96 Shin-Etsu Chemical Organic solvent D: Aliphatic hydrocarbon solvent, organic pigment I: Aniline black Carbon black: Furnace black dye J: Nigrosine dye Dye K: Azo dye Surfactant: Nonionic surfactant oil Soluble resin: rosin resin Tables 2 to 4 show ink composition examples of Examples 4 to 7 of the color inks (three colors) for inkjet recording of the present invention.

[0032]

[Table 2]

Si solvent A: Technocare FRV manufactured by Toshiba
B: Technocare FRS manufactured by Toshiba
C: Silicone oil KF96 Shin-Etsu Chemical Organic solvent F: Alcohol solvent Organic pigment Y: Disazo Yellow HR Organic pigment M: Naphthol Red 23 Organic pigment C: Phthalocyanine blue Surfactant: Nonionic surfactant + fluorine surfactant Oil-soluble resin: rosin resin

[0034]

[Table 3]

Si solvent A: Technocare FRV manufactured by Toshiba
B: Technocare FRS manufactured by Toshiba
C: Silicone oil KF96 Shin-Etsu Chemical Organic solvent D: Aliphatic hydrocarbon solvent, organic solvent F: Alcohol solvent Dye Y: Acid Yellow 23 Dye M: Acid Red 254 Dye C: Phthalocyanine dye Surfactant: Nonionic interface Activator oil-soluble resin: rosin resin

[0036]

[Table 4]

Si solvent A: Technocare FRV manufactured by Toshiba
B: Technocare FRS manufactured by Toshiba
C: Silicone oil KF96 Shin-Etsu Chemical Organic solvent D: Aliphatic hydrocarbon solvent, Organic solvent G: Polyhydric alcohol solvent Organic pigment Y: Acid Yellow 23 Inkjet organic pigment M: Acid Red 254 Organic pigment C: Phthalocyanine dye Y: Acid Yellow 23 Dye M: Acid Red 254 Dye C: Phthalocyanine dye Surfactant: Nonionic surfactant Oil-soluble resin: Rosin resin Table 5 shows comparative examples of the inkjet recording ink of the present invention. Example 1 shows an example of a black ink composition that does not contain a silicone solvent, and Comparative Example 2 shows an example of a color ink composition that does not contain a silicone solvent.

[0038]

[Table 5]

Organic solvent F: alcoholic solvent organic solvent G
: Polyhydric alcohol solvent Carbon black: Furnace black Dye J: Nigrosine dye Organic pigment Y: Acid Yellow 23 Inkjet organic pigment M: Acid Red 254 Organic pigment C: Phthalocyanine dye Dye Y: Acid Yellow 23 Dye M: Acid Red 254 Dye C: Phthalocyanine dye Surfactant: Nonionic surfactant Oil-soluble resin: Rosin resin The above inkjet recording ink was prepared according to the following procedure. First, the composition shown in the above table is stirred and dispersed using an ultrasonic disperser, and uniform dispersion of the coloring material is confirmed. If the dispersion was insufficient, the mixture was stirred and dispersed using a ball mill for several hours. At this time, the particle size is 0.5 to 5 μm
is preferred, but not limited to this.

The method for producing the inkjet recording ink of the present invention is not limited to the above-mentioned method, but may also be produced by roll mill dispersion, emulsion method, microcapsule method, etc.

Next, using the black inkjet recording inks of Examples 1 to 3 and Comparative Example 1, a printing test was conducted using an inkjet printer as shown in FIG. The printing test was conducted at a resolution of 300 DPI with two types of patterns: one-dot line and solid printing, on five types of transfer papers with different characteristics.

Printing was evaluated by evaluating the dot shape stability using a one-dot line pattern and the quick-drying property of printing using a full solid pattern.

Table 6 shows the dot shape stability evaluation results of the present example and comparative example.

[0044]

[Table 6]

○ Dot shape is always stable △
Bleeding occurs partially due to paper fibers × Ink whiskers occur along the paper fibers Paper A: Copy paper Paper D: Inkjet paper Paper B: Recycled paper
Paper E: Art Paper Paper C: Low Smoothness Paper Table 7 shows the quick drying evaluation results of the present example and comparative example.

[0046]

[Table 7]

*The number of seconds in the table is from the time the ink is transferred,
As shown in Table 6, which is the time taken to fix, Example 1
- The ink of Example 3 provided printing with excellent shape stability without bleeding regardless of the paper type. However, with the ink of the comparative example, whisker-like bleeding was observed on copy paper and recycled paper, and stable printing could not be obtained.

Further, as shown in Table 7, the inks of Examples 1 to 3 were fixed in 10 seconds or less, whereas the inks of Comparative Examples all required 30 seconds or more.

Next, using the color inkjet recording inks of Examples 4 to 6 and Comparative Example 2, a three-color overlapping color image was printed. The resolution was 75 DPI, and the number of gradations was 16 using the dither method. The photographic paper used was the above-mentioned five types of transfer paper.

Table 8 shows the image quality evaluation results of the color inks of Examples 4 to 6 and Comparative Example 2.

[0051]

[Table 8]

○ Clear color with no color mixture △ Color mixture occurs in high-density areas × Color mixture occurs throughout, resulting in a blurred image Paper A:
Copy paper Paper D: Inkjet paper Paper B: Recycled paper Paper E: Art paper Paper C: Low smoothness paper As shown in Table 8, the inks of Examples 4 to 6 are clear with no color mixing regardless of the paper type. A great image was obtained. However, the ink of Comparative Example 2 not only caused whisker-like bleeding on copy paper and recycled paper, but also caused color mixing, resulting in a blurred image.

From the above results, if the inkjet recording ink of the present invention is used, good print quality can be obtained regardless of the paper quality, sufficient printing durability can be obtained within a few seconds after printing, and color mixing can be avoided in color images. This has the effect that a clear image without any blemishes can be obtained.

[0054]

[Effects of the Invention] As explained above, when the inkjet recording ink of the present invention is used, it has a high compatibility with various transfer objects, and stable print quality and quick drying properties can be obtained for various transfer objects. , and it becomes possible to obtain a clear color image without color mixture.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the concept of the ink ejection principle of an inkjet printer of the present invention.

FIG. 2 is a schematic diagram showing the concept of the fixing principle of the inkjet recording ink of the present invention.

[Explanation of symbols]

1 Nozzle forming substrate 2 Pressurized ink 3 Discharged ink 4 Nozzle 5. Ink that collided with the transferred object 6 Dots formed on paper 7 Transferred object 8 Penetrated silicone solvent 9 Pressure generating member

Claims (3)

[Claims] Claim 1: At least a boiling point of 100°C to 250°C
An inkjet recording ink characterized by containing 2 to 95 wt (%) of a silicone-based solvent having a temperature of 2 to 95 wt. 2. The inkjet recording ink according to claim 1, wherein the colorant is an organic pigment or carbon black. 3. The inkjet recording ink according to claim 1, wherein the coloring material is a dye.