JP3047435B2 - Image recording ink - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image recording ink for recording characters and images using liquid ink.

[Conventional technology]

Conventionally, aqueous inks have been the mainstream ink used for ink jet recording systems in terms of odor, safety, etc., and various water-soluble dyes are dissolved in water or a mixed solvent of water and a water-soluble organic solvent. Currently, dissolution-based inks to which various additives are added are used. Advantages of these ink jet recordings are direct recording, which simplifies the process, is noiseless, is easy to colorize, is capable of high-speed recording, and has low running costs because plain paper can be used. In addition, the ink jet recording apparatus has excellent features such as high-resolution recording because it ejects minute ink droplets, and is attracting attention in the future.

[Problems to be solved by the invention]

However, according to the above-mentioned prior art, (1) the ink bleeds on the object to be transferred, and a high-quality recorded image cannot be obtained.

(2) The drying speed of the ink on the transfer object is low, and tailing occurs.

(3) Poor fixability.

(4) Clogging is easy.

(5) The concentration is low.

(6) No water resistance.

And other issues.

Also, in order to solve the above-mentioned problem, for example,
Japanese Patent No. 29546 discloses a method in which a specific surfactant is added to reduce the surface tension to increase the absorbability of ink on paper.Japanese Patent Application Laid-Open No. 56-57862 discloses a strong base. JP-A-58-13675 discloses a method for controlling the spread and absorption of dots by chemically dissolving a sizing agent or pulp material which is a water-resistant treatment agent for plain paper by adding a substance to a high pH (paper). Has proposed a method in which polyvinylpyrrolidone having a molecular weight of 40,000 or more is added to ink to control the spread of dots and the absorbability to paper. However, these attempts are not intended to completely solve the above problems. is not.

Therefore, the present invention solves such a problem, and a first object of the present invention is to provide a high-density image with a clear outline that does not cause bleeding of characters and images on any transfer target.
An object of the present invention is to provide an ink for image recording that enables high gloss printing.

A second object of the present invention is to provide an ink for image recording that can be dried and fixed quickly, has no tailing, enables high-speed printing, and enables full-color images by overlapping process colors.

A third object of the present invention is to provide an image recording ink which is excellent in ejection stability and storage stability in which clogging does not occur in a nozzle and an ink circulation path.

A fourth object of the present invention is to provide an image recording ink having excellent water resistance and light resistance.

[Means for solving the problem]

The image recording ink of the present invention is an image recording ink used for a printing device that performs recording of characters and images with liquid ink, wherein the constituent components of the image recording ink include at least water and a colorant, and at least water It contains an insoluble component.

〔Example〕

Hereinafter, the form and components of the image recording ink of the present invention will be specifically exemplified.

The ink of the present invention comprises at least water and a colorant,
Contains at least components that do not dissolve in water.

As the coloring agent used in the present invention, any dyes which do not change color tone or generate precipitates by adding other ink components to water-soluble dyes and oil-soluble dyes used in conventional inks can be used. But can be used.

Pigments can also be used as colorants, and inorganic pigments (carbon black), organic pigments (insoluble azo pigments,
Soluble azo pigments, phthalocyanine-based pigments, isoindolinone-based higher pigments, quinacridone-based higher pigments, perinone / perylene-based higher pigments, and the like can be used. In addition, a processed pigment (graft carbon or the like) having a pigment surface treated with a resin or the like can be used.

It is preferable that the particle diameter of the colored particles and the pigment is 1.0 μm or less.

If the amount of the dye / pigment added is less than 0.5% by weight,
The desired color tone and density cannot be obtained, and if the content exceeds 20% by weight, clogging and storage stability may be impaired.
5 to 20% by weight is preferred.

When a dye is used as a coloring agent, it is used in combination with a water-insoluble component. For example, the dye can be used by impregnating, chemically adsorbing, and supporting it in the water-insoluble polymer dispersed particles.

When a pigment is used as the colorant, the pigment itself can be used as a water-insoluble component dispersed in water, or can be used in combination with another water-insoluble component.

Examples of the water-insoluble component other than the colorant include vinyl ester type, acrylic ester type, methacrylic ester type styrene type, olefin type and amino group, carboxyl group, amide group, and monomers having a hydrophilic functional group such as a hydroxyl group. Homopolymerized or copolymerized resin emulsion, organic three-dimensionally crosslinked organic ultrafine particles, microemulsion,
Colloidal dispersion, or natural or synthetic wax emulsions such as paraffin wax, microcrystalline wax, polyethylene wax carnauba wax and the like can be used. These can be produced by emulsion polymerization, suspension polymerization, dispersion polymerization, or pulverizing a polymer polymerized by any method. In addition, inorganic ultrafine particles such as colloidal silica can also be used.

The above emulsion can be used as a colored emulsion which is colored with a dye and insoluble in water. Further, it can be added as a water-insoluble component separate from the coloring agent.

Solvents used in the present invention include ion-exchanged water, water-soluble organic solvents such as alkyl alcohols having 1 to 4 carbon atoms, ketones or keto alcohols, ethers, polyalkylene glycols, and alkylene groups having 2 to 6 carbon atoms. Alkylene glycols, glycerin, lower alkyl ethers of polyhydric alcohols, N-methyl-2-pyrrolidone, triethanolamine, and the like, but are not limited thereto.

Examples of the water-soluble resin used for improving fixability, viscosity control, and quick drying include glue, gelatin, casein, albumin, gum arabic, alginic acid, methylcellulose, carboxymethylcellulose, polyethylene oxide, hydroxyethylcellulose, polyvinyl alcohol, and polyacrylic acid. , Polyvinyl ether, polyvinyl pyrrolidone and the like can be used in combination with the water-insoluble component.

In addition, other than those in which the dye is dissolved in water, only a solvent is allowed to permeate, leaving a coloring component on a transferred body, and various surfactants, methyl Alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, diethylene glycol monobutyl ether,
Triethylene glycol monomethyl ether, N-methyl-pyrrolidone, 1,3 dimethylimidazolidinone and the like can be used.

Although the basic constitution of the present invention is as described above, conventionally known dispersants, viscosity modifiers, surface tension modifiers, specific resistance modifiers,
A pH adjuster, a fungicide, a chelating agent and the like can be added as needed.

In terms of the physical properties of the ink, the ink viscosity when the temperature during operation is set to 0 ° C. to 5 ° C. is close to the ejection nozzle in consideration of the stability of ink supply and the stability of ink droplet flight under high-speed response of the head. 20 mPa · s or less is required in
1010 mPa · s is more preferable.

The surface tension of the ink is preferably not less than 40 dyne / cm, and if it is less than 40 dyne / cm, bleeding occurs on a transfer medium having a low size treatment, and the paper handling rate is reduced.

Means for uniformly dispersing the water-insoluble component in the dispersion medium include the action of charge repulsion, the action of protecting the adsorption layer formed by the surfactant or the polymer protective colloid, and the function having a reactive group soluble in the dispersion medium. There is a method in which a polymer having a group is bonded to the surface of the coloring component by a chemical reaction, a method in which a known coupling agent is bonded to the surface of the coloring component by a chemical reaction, and the like. Therefore, stable dispersibility can be obtained.

Among the pigment dispersion methods of the recording ink production method of the present invention, a ball mill, a sand mill, an attritor, a roll mill, an agitator mill, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a high-pressure homogenizer,
A fine pulverizer / ultra-pulverizer such as a pearl mill, a jet mill, an ong mill, a mechanofusion (Hosokawa Micron), a hybridization (Nara Machinery Co., Ltd.) and the like can be used.

Further, if necessary, it is necessary to perform filtration under reduced pressure and pressure through a filter or the like to remove giant particles, dust, contaminants, etc., or to stir, mix and prepare the ink to form a final ink.

Further, the image recording ink of the present invention may be provided with hot air or
Drying and fixing can also be performed by a heat fixing means such as a heating roll or infrared rays.

Further, the image recording ink according to the present invention is a conventional on-demand type ink jet, a nozzle forming substrate having a plurality of nozzles in addition to the ink mist method of generating a mist by ultrasonic waves, and the like, A piezoelectric transducer that is disposed in the vicinity and constitutes a vibrator that can be driven independently by being immersed in ink is provided, and the piezoelectric transducer is displaced by applying voltage to pressurize the ink inside the nozzle forming substrate and In an ink jet system in which printing is performed by discharging from a nozzle, a portion in contact with the ink of the piezoelectric converter can be used by insulating it. Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not intended to limit the present invention.

(Example 1) The amounts (%) of the ink compositions shown in the following examples are all% by weight.

CI Solvent Black 233 3% Methyl methacrylate 11% n-butyl acrylate 7% Glycidyl methacrylate 2% Deionized water 67.5% Sodium dodecyl sulfate 1% Potassium persulfate 0.5% Glycerin 8% Temperature control device, stirrer, nitrogen gas inlet tube, dropping After replacing with a nitrogen gas in a flask equipped with a funnel, sodium dodecyl sulfate and ion-exchanged water are added, and the mixture is heated to 70 ° C., and potassium persulfate is added dropwise over 3 hours, and is composed of methyl methacrylate and n-butyl acrylate glycidyl methacrylate. The monomer mixture was added dropwise over 2 hours.

After the completion of the dropwise addition of potassium persulfate, the temperature was raised to 80 ° C., the mixture was stirred for 1 hour, and filtered under reduced pressure with a filter having a pore size of 1.2 μm to prepare a resin emulsion having an average particle size of 0.8 μm.

A solution prepared by dissolving CI Solvent Black 23 in acetone was added to the prepared resin emulsion, and the mixture was stirred for 2 hours.
Remove acetone with evaporator and add glycerin
After stirring for 30 minutes and filtering under reduced pressure through a filter having a pore size of 1.2 μm, a recording ink having a surface tension of 48 dyne / cm was prepared.

Example 2 5% of ethyl alcohol was added as a penetrant to the recording ink experimentally produced in Example 1 to prepare a recording ink having a surface tension of 42 dyne / cm.

(Example 3) Carbon black 6% Acrylic resin 3% Glycerin 10% Deionized water 80% After kneading an acrylic resin and carbon black by a roll mill, disperse them for 10 hours using a sand mill, transfer to a stirrer, and remove glycerin. The mixture was filtered under reduced pressure using a 1 μm filter to obtain an average particle size of 0.08 μm and a surface tension of 58 dy.
A recording ink of ne / cm was prepared.

(Example 4) N- as a penetrant was added to the recording ink experimentally produced in Example 3.
Add 5% methyl-2-pyrrolidone, surface tension 49dyne / c
m of recording ink was prepared.

(Example 5) Carbon black 6% Polyvinylpyrrolidone 3% (K = 15) Nonionic dispersant 0.8% Glycerin 10% Deionized water 79.2% Polyvinylpyrrolidone, carbon black and dispersant are dispersed for 15 hours using a paint shaker. Then, the mixture was transferred to a stirrer, glycerin was added, and the mixture was filtered under reduced pressure using a 1 μm filter to give an average particle size of 0.2 μm and a surface tension of 63 dyne / cm.
Was prepared.

(Example 6) As a penetrant for the recording ink experimentally produced in Example 5,
3 Dimethyl 2 imidazolidinone 5% added, surface tension 5
A recording ink of 1 dyne / cm was prepared.

(Example 7) Carbon black 6% Super microemulsion 30% (Solid content 20% PB-300 manufactured by Kao) Glycerin 15% Ion exchange water 48.2% Nonionic dispersant 0.8% Ion exchange water, nonionic dispersant and carbon black Was dispersed in a sand mill for 10 hours, the supermicroemulsion and glycerin were added thereto, stirred for 1 hour, and filtered under reduced pressure using a 1 μm filter to obtain a recording ink having an average particle size of 0.08 μm and a surface tension of 48 dyne / cm. Produced.

Example 8 5% of diethylene glycol monobutyl ether was added as a penetrant to the recording ink prepared in Example 7 to prepare a recording ink having a surface tension of 41 dyne / cm.

(Example 9) CI Direct Black 154 3% Organic ultrafine particles (solid content 25%) 40% (Microgel Nippon Paint) Ion exchange water 52% Glycerin 6% Dissolve CI Direct Black 154 in ion exchange water,
Organic ultrafine particles (solid content 25%) and glycerin were added, and the mixture was stirred for 1 hour with a stirrer. The mixture was filtered under reduced pressure using a 0.8 μm membrane filter to obtain an average particle size of 0.03 μm and a surface tension of 45 dyne / c.
m of recording ink was prepared.

(Example 10) CI.PIG. Yellow 12 6% Polyvinylpyrrolidone 4% Nonionic dispersant 4% Glycerin 10% Deionized water 76% CI.PIG. Red 146 6% Polyvinylpyrrolidone 4% Nonionic dispersant 4% Glycerin 10% ion exchange water 76% CI.PIG. Glue 15-3 6% polyvinylpyrrolidone 4% nonionic dispersant 4% glycerin 10% ion exchange water 76% polyvinylpyrrolidone, yellow, magenta, cyan pigments and nonionic dispersion Each of the agents was dispersed for 20 hours using a paint shaker, transferred to a stirrer, added with glycerin, and filtered under reduced pressure using a 1 μm filter.
A recording color ink having an average particle size of 0.2 μm and a surface tension of 61 dyne / cm was prepared.

Example 11 1% of sodium dioctylsulfosuccinate was added as a penetrant to the color ink prepared in Example 10 to prepare a recording color ink having a surface tension of 43 dyne / cm.

(Comparative Example) As Comparative Example 1, a commercially available ink for an on-demand inkjet printer was used, and as Comparative Example 2, a commercially available ink for a bubble jet printer was used. Each composition is as follows.

Comparative Example 1 CI Direct Black 19 2% Glycerin 15% Ion-exchanged water 83% Surface tension 48dyne / cm Comparative Example 2 CI Direct Black 19 2% Diethylene glycol 10% Ethanol 5% Ion-exchanged water 83% Surface tension 46dyne / cm or more ink As a recording method, a commercially available on-demand type ink jet printer and a prototype multi-head (discharge orifice diameter 50 μm, piezo vibrator drive voltage 80
V, drive frequency 3kHz), general quality paper, bond paper, P
Characters, graphics, etc. were printed on various types of transfer media such as PC paper, recycled paper, and general OHP sheets, and the following evaluations were made.

 The evaluation method is shown below.

1. Bleeding evaluation Observation at 100x and 400x with a microscope and visual observation ◎: Dots are retained on the fiber without bleeding along the fiber ○: There is little bleeding along the fiber but it is not visible △: Slight bleeding is visually observed. ×: Quite blurred and jagged edges 2. Evaluation of quick-drying After 10 seconds, 30 seconds, and 60 seconds after printing, rub the printed portion with the edge of paper ◎: 10 seconds No tailing afterwards ○: No tailing after 30 seconds △: No tailing after 60 seconds ×: With tailing after 90 seconds 3. Fixability evaluation One hour after printing, the printed surface is clipped at 200 g / cm Evaluation of the presence or absence of dirt due to rubbing by applying a load of ◎: No dirt after 30 round trips ○: Dirt after 20 to 30 round trips ×: Dirt below 20 round trips 4.Evaluation of clogging Filled with ink and stored in a 50 ° C environment for 1 month with no nozzle cap After standing ○: Immediately printable △: Printable by circulating ink and cleaning ×: Not printable 5. Ink preservability Put the ink in a sample bottle, store in a sealed state at 50 ° C for 6 months, and remove foreign matter -Confirm the presence or absence of off-flavor, aggregation and precipitation ◎: None ○: Sedimentation is observed but easily re-dispersed ×: Not re-dispersed 6. Recording density Measurement of reflection O / D value by Macbeth densitometer 7. Water resistance evaluation Printed matter 1 hour after printing is immersed in water for 5 minutes and the outflow of ink is observed. ○: No ×: Yes 8. Glossiness measurement Measurement of 75-degree specular glossiness with a digital gloss meter (Murakami Color Research Laboratory) ○ : 80 or more △: 51-79 ×: 50 or less 9. Recording on OHP paper ○: Recordable ×: Not recordable 10.Evaluation of light resistance Discoloration of xenon lamp 100 hours irradiation blue scale ○: Less than 50% ×: 50% The method for investigating the physical properties of ink is shown below.

A. Viscosity Steady-state viscosity measurement at 20 ° C with a fluid spectrometer manufactured by Rheometrics Far East B. Surface tension Measurement with a surface tensiometer (Kyowa Interface Science) C. Average particle size Laser light scattering zeta potentiometer ELS800 ( Particle size distribution measurement by Otsuka Electronics Co., Ltd. The above results are shown in Table 1.

As is evident from Table 1, the recording inks of Examples 1 to 6 have a conventional printing quality (bleeding, density, gloss, water resistance and light resistance), fast drying property, fixability, clogging and ink storability. Very good results were obtained compared to the inkjet ink.

As described above, according to the embodiment of the present invention, when the recording ink adheres to the transfer receiving member, as shown in FIG. 1, the coloring component remains at the position where the coloring component adheres due to the cohesive force of the component that does not dissolve in water. , Dots with sharp outlines are solidified and fixed.

[Effects of the Invention] As described above, according to the image recording ink of the present invention, the dispersion system contains at least water and a colorant and contains at least a component that is insoluble in water. High-density, clear recording with excellent water resistance and light resistance, enabling unprecedented quick-drying and fixing properties, no clogging, and excellent ink storage stability. This has the effect of enabling the performance.

Further, the image recording ink of the present invention has an effect that high-speed, high-quality printing is possible even on general OHP paper that cannot be used in ordinary ink jet recording.

Further, since the recording ink has good drying and fixing properties, a high-resolution full-color image can be recorded by using three process color inks.

In addition, the present invention has an effect of enabling clear recording without bleeding on recycled paper which is expected to spread rapidly in the future.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing ink dots on a transfer object according to the present invention. 1 Outline 2 Fiber A Transferee

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 11/00-11/20

Claims (11)

(57) [Claims] An average particle size of at least 1.0 μm, comprising at least water, a colorant and glycerin, and not soluble in water.
An ink jet recording ink comprising at least one of the following components. 2. The water-insoluble component has an average particle size of 0.8.
The ink for inkjet recording according to claim 1, which has a size of not more than μm. 3. The component insoluble in water is a colorant.
The ink for inkjet recording according to claim 1. 4. The ink jet recording ink according to claim 3, wherein said colorant is a pigment. 5. The method according to claim 1, further comprising a water-soluble resin.
5. The ink jet recording ink according to any one of items 4 to 4. 6. The ink for ink-jet recording according to claim 5, wherein said water-soluble resin is polyvinylpyrrolidone. 7. The ink jet recording ink according to claim 1, comprising a water-insoluble resin as the water-insoluble component, and wherein the colorant is a dye. 8. The method according to claim 1, wherein the water-insoluble resin is a resin emulsion,
The inkjet recording ink according to claim 7, which is in the form of organic ultrafine particles, microemulsion, or colloidal dispersion. 9. The ink jet recording ink according to claim 1, wherein the glycerin content is 6% by weight or more. 10. An ink jet recording method for ejecting droplets of an ink composition and attaching the droplets to a recording medium to perform printing, wherein the ink composition is any one of claims 1 to 9. Using the inkjet recording ink of the description,
Ink jet recording method. 11. A recorded matter on which an image has been recorded by the ink jet recording method according to claim 10.