JPH0892513A - Ink for color ink jet and method for recording - Google Patents

Abstract

PURPOSE: To obtain the subject ink, designed to rapidly separate colored resin particles in the ink from a solvent on paper and capable of preventing the bleeding and outputting a high-quality color image without any roughness or color shift regardless of the paper quality or an ink in the ground. CONSTITUTION: This ink for color ink jet contains colored resin particles dispersed in the form of fine particles in a solvent consisting essentially of water. The ink is capable of separating the solvent from the colored resin particles when applied onto a colored resin recorded on a medium to be recorded. Furthermore, the colored resin particles have preferably 0.1-5μm weight-average particle diameter and 0.95-1.2 specific gravity. This method for recording comprises preferably rapidly separating the solvent 5 in the ink from the colored resin particles 1 in the ink preapplied onto the medium 4 to be recorded, fixing the colored resin particles 1 and then discharging ink droplets 20 of the second color into overlapped positions in forming the color image on the recording medium according to a color ink jet recording method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink jet ink and a recording method.

[0002]

2. Description of the Related Art Conventionally, as the ink used in a color ink jet recording method, an ink in which a dye is dissolved in water and an organic solvent or the like is further added, if necessary, has predominated. Hereinafter referred to as water-based ink.

However, conventional water-based inks are slow to dry after printing, and the printing quality on plain paper has not been sufficiently satisfactory. In particular, since a color image is generally formed from each color of yellow, magenta, cyan, and black, when the dots are to be formed by an inkjet recording method, ink may be mixed in a portion where areas of different colors are in contact with each other, Flowed out into the area of color, causing deterioration of the color image.

Therefore, in order to obtain a clear color image,
The following proposals have been made. For example, JP-A-63-
In US Pat. No. 2,338,811 and US Pat. No. 5,196,056, a solvent such as diethylene glycol monobutyl ether is contained in the ink to increase the penetrability into a recording medium, thereby causing ink mixing or running between adjacent dots. We have realized a color image that suppresses this.

Further, for the purpose of preventing bleeding onto paper, colored particles which are difficult to penetrate into paper are dispersed in a solvent, and a colored portion formed of the particles is formed on the paper to prevent bleeding. Such a proposal has been made. For example, Japanese Patent Publication No. 3-807470 has a surface tension of 5
Bleeding was prevented by using an ink in which fine particles having a particle diameter of 0.01 μm or more were dispersed in a non-aqueous solvent composed of a liquid of 0 mN / m or less. Also, in JP-A-4-185672, an ink in which sedimentation and bleeding of particles are prevented by using an ink in which a difference in specific gravity between an aqueous medium and colored resin particles dispersed in the aqueous medium is less than 0.04 Is disclosed.

[0006]

However, in the conventional image forming method using the color ink, when the water absorption of the paper is changed by the surface shape of the paper into which the ink permeates or the thickness of the paper fiber, or the ink is overlaid. When the color and pattern of the underlying ink at that time changes, the way the ink spreads changes, which causes the dot diameter to fluctuate, resulting in a rough texture or color shift. was there.

Further, in the ink in which the bleeding is prevented by dispersing the colored particles in the solvent, the bleeding of the first color can be prevented, but when two or more inks are superposed, the image is printed first. There is a problem in that another ink that has been printed later bleeds on the ink, and a rough feeling and a color shift occur in a color image.

Therefore, the present invention solves these problems, and its purpose is to prevent bleeding regardless of the paper quality and the ink of the base, so that a high-quality color image free from graininess and color misregistration is obtained. It is an object of the present invention to provide a color inkjet ink and a recording method capable of outputting the same.

[0009]

The color inkjet ink of the present invention comprises a solvent containing at least water as a main component,
An ink consisting of colored resin particles finely dispersed in this solvent, and when the recording medium or the colored resin particles in the ink previously recorded on the recording medium adheres to the solvent and the colored resin particles, Are separated.

In the color ink-jet ink of the present invention, the weight average particle diameter of the colored resin particles is preferably 0.1 to 5 μm, and the specific gravity of the colored resin particles is 0.95 to 1.2. Is preferred.

Further, the color ink jet recording method of the present invention is a color ink jet recording method in which ink droplets are ejected from a recording head onto a recording medium to form an ink image, and the ink is recorded selectively according to image data. When a color image is formed on the recording medium by ejecting ink, the solvent of the ink previously attached to the recording medium and the colored resin particles are separated, and then an ink droplet of another color is ejected at the overlapping position. It is characterized by doing.

Further, when the color image is printed, the recording medium is heated by the heating means, and after the color image is printed, the heating means heats and fixes the image.

[0013]

The color ink-jet ink of the present invention is one in which colored resin particles are dispersed in a solvent containing water as a main component, and the dot diameter variation can be suppressed and high image quality can be achieved by the following mechanism.

As shown in FIG. 1, the solvent 5 in the ink of the first color and the colored resin particles 1 are quickly separated on the paper surface 4, and the colored resin particles 1 are fixed and cannot move.
Overprint the color inks.

Then, the second color ink comes into contact with the colored resin particles 1 in the first color ink, so that the colored resin particles 2 are separated from the solvent 5 and fixed on the colored resin particles 1.
It is possible to prevent the second color ink from mixing, flowing, spreading, and the like. Similarly, for the third color, after the first and second colored resin particles 1 and 2 are fixed, the third colored ink is superposed and printed, so that the third colored resin particle 3 becomes the solvent 5.
By being separated and fixed on the colored resin particles of the first or second color, mixing, flow, spread, etc. of the third color can be prevented.

Further, when the weight average particle diameter is in the range of 0.1 to 5 μm, the resistance against movement of particles on the paper is increased, and the colored resin particles are fixed more quickly, so that the color overlapping time is increased. Can be shortened.

Further, by setting the specific gravity of the particles to 0.95 to 1.2, not only the sedimentation of the particles due to the difference in the specific gravity is prevented, but also the uniformity of the ink appears, so that the heavy and large particles cause the surface of the paper to come out. If the solvent is covered, the solvent component is not impeded to permeate the paper, and uniform permeation is performed, so that the solvent and the colored resin particles can be separated more quickly.

Further, by heating the recording medium in the above process, the separation speed becomes faster, the time interval of superposition can be shortened, and the printing speed can be increased.

Further, by post-fixing the image in which the inks of a plurality of colors are superposed by the heating means, the image quality can be improved by clarifying the edges and making the dots of each color uniform.

Further, the heat-fixed image has a scratch resistance,
The image has water resistance and excellent fastness.

[0021]

EXAMPLES The color ink-jet ink and recording method according to the present invention will be described below with reference to examples.

First, the ink will be described.

The main constituent components of the ink used in the present invention are a colored resin particle component and a solvent having water as a dispersion medium as a main component.

The colored resin particles of the present invention are composed of at least a resin component, a colorant, and an additive which is appropriately added to improve its properties.

Resins that can be used for the colored resin particles of the present invention include polystyrene, styrene-acrylic acid ester copolymer, polyacrylic acid ester, polymethacrylic acid ester, polyethylacrylic acid ester,
Styrene-butadiene copolymer, butadiene copolymer,
Acrylonitrile-butadiene copolymer, chloroprene copolymer, crosslinked acrylic resin, crosslinked styrene resin, vinylidene fluoride, benzoguanamine resin, polyethylene resin, polypropylene resin, styrene-methacrylic acid ester copolymer, styrene-acrylamide copolymer,
It is possible to use n-isobutyl acrylate, vinyl acetate, acrylamide, polyvinyl acetal, rosin resin, vinylidene chloride resin, ethylene-vinyl acetate copolymer, vinyl acetate-acrylic copolymer, vinyl chloride resin and the like.

The above resins are preferably fused by the heating means described later, and the phase change temperature thereof is 50 ° C. to 100 ° C. in order to prevent deterioration of the ink when it is left at a high temperature and to reduce the energy required for heat fusion. ℃ is preferred, more preferably 6
5 ° C to 90 ° C is preferable.

As the colorant for the resin particles, a pigment, an oil-soluble dye or a disperse dye is used, and it is preferable that the resin particles are excellent in colorability and dyeability and do not dissolve in water as a dispersion medium.

Pigments that can be used in the colored resin particles of the ink of the present invention include organic pigments and inorganic pigments. For black, for example, furnace black, lamp black, acetylene black, channel black and the like can be used. Carbon black (C.I. pigment black 7), or copper, iron (C.I. pigment black 1)
1), metals such as titanium oxide, aniline black (C.
I. Pigment Black 1) and other organic pigments.

Further, for color, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Genius Yellow AA)
A), 13, 14, 17, 24, 34, 35, 37, 4
2 (yellow iron oxide), 53, 55, 81, 83 (this as yellow HR), 95, 97, 98, 100, 101, 104,
108, 109, 110, 117, 120, 138, 1
53, C.I. I. Pigment Orange 5, 13, 16, 1
7, 36, 43, 51, C.I. I. Pigment Red 1,
2, 3, 5, 17, 22 (Brilliant First Scarlet), 2
3, 31, 38, 48: 2 (Permanentlet 2B (Ba)), 4
8: 2 (Permanentlet 2B (Ca)), 48: 3 (Permanentlet 2B)
(Sr)), 48: 4 (Permanentlet 2B (Mn)), 49: 1, 5
2: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1,
63: 1, 63: 2, 64: 1, 81 (Rotamine 6G rake), 8
3, 88, 101 (Bengara), 104, 105, 10
6, 108 (Cadmium Let), 112, 114, 122
(Quinacrid magenta), 123, 146, 149, 166,
168, 170, 172, 177, 178, 179, 1
85, 190, 193, 209, 219, C.I. I. Pigmen Violet 1 (Rotamine Lake), 3, 5: 1, 16,
19 (quinacridlet), 23, 38, C.I. I. Pigment Blue 1, 2, 15 (Phthalocyanine Blue R), 15: 1, 1
5: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6
(Phthalocyanine blue E), 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 3
6, etc., and other processed pigments such as graft carbon whose surface is treated with a resin can be used. The addition amount thereof is preferably 0.5 to 30% by weight with respect to the resin, and further 1.
0 to 12% by weight is more preferable.

The oil-soluble dyes and disperse dyes used for the colored resin particles of the ink of the present invention include C.I. I. Solvent Black 3, 5, 22, C.I. I. Solvent Yellow 1
9, 44, 98, 104, 105, 112, 113, 1
14 C. I. Solvent Red 8, 24, 71, 109, 1
52, 155, 176, 177, 179 C.I. I. Solvent Blue 2, 11, 25, 78, 9
4, 95, C.I. I. Solvent Green 26, C.I. I.
Solvent Orange 5, 40, 45, 72, 63, 6
8, 78 C.I. I. Solvent Violet 13, 31, 32, 3
3, C.I. I. Disperse Yellow 3, 5, 56, 6
0, 64, 160 C.I. I. Day Super Red 4, 5, 60, 72, 7
3, 91, C.I. I. Desperce Blue 3, 7, 56,
60, 79, 198 C.I. I. Disperse oranges 13, 30 and the like are used, but not limited to these.

The amount of these dyes added is determined depending on the type of resin, the properties required for the ink, etc., but is generally 1 to 20% by weight, preferably 2 to 15% by weight with respect to the resin component. % Range is good.

The particle size of the colored resin particles is 0.1 to 0.1% from the viewpoint that the solvent and the colored resin particles are quickly separated, and that clogging at the nozzle is unlikely to occur.
The range is preferably 5 μm, more preferably 0.3 to 1
μm is desirable.

The specific gravity of the colored resin particles is set to 0.95 to 1.5 in order to prevent sedimentation in an aqueous solvent, instability of ejection due to nonuniformity of particle concentration, and uniform solvent permeability.
2 is preferred.

As a means for reducing the specific gravity of the colored resin particles, it is effective to swell the colored resin particles, make voids in the resin particles, use activated carbon as a coloring agent, and the like.

Water, which is the main solvent of this ink, is ion-exchanged,
Pure water or ultrapure water that has undergone a purification process such as distillation is desirable.

A hydrophilic high-boiling point low-volatile solvent is added to the solvent of the ink of the present invention in order to impart the effects of nozzle clogging resistance, moisture retention and dispersion stability. Examples of the hydrophilic high-boiling point low-volatile solvent used in the present invention include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, etc. Polyhydric alcohols are used, or their monoethers, diethers, and esters, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether. Butyl ether etc. are used,
Others N-methyl-2-pyrrolidone, 1.3-dimethylimidazolidinone, monoethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, diethanolamine, N-n-butyldiethanolamine, triisopropanolamine, triethanol A water-soluble organic solvent such as a nitrogen-containing organic solvent such as an amine can be added within a range in which the flow of printing does not cause bleeding.

Further, with respect to water, which is the main solvent, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol, Highly volatile monohydric alcohols such as can be added.

Examples of the water-soluble polymer that can be used by dissolving it in the aqueous solvent of the present ink include polyalkyl oxides such as polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl butyral, alkali-soluble acrylic resin, Glue, gelatin,
Monosaccharides such as casein, albumin, gum arabic, alginic acid, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl ether, polyvinyl methyl ether, polyethylene glycol, α-cyclodextrin, glucose, xylose, sucrose, maltose, arabinose, maltitol and starch. , Disaccharides, polysaccharides, glycosides and the like.

The water-soluble polymer has an effect of preventing the colored resin particles from moving and peeling by adhering the colored resin particles to the paper after the colored resin particles and the solvent component in the ink are separated. The addition amount is 1 by weight with respect to the colored resin particles.
/ 10 to 1/1 is preferable. In addition, excessive addition may increase the viscosity of the ink itself, and may adversely affect ink supply, stable ejection, and the like.
t% or less is preferable.

Further, as a surfactant which can be added for controlling the surface tension of the solvent or for obtaining the dispersion stability of the colored resin particles, for example, anionic surfactants include higher fatty acid salts and higher alkyldicarboxylic acids. Salt, higher alcohol sulfate ester salt, higher alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonic acid salt (Na,
K, Li, Ca) formalin polycondensate, condensate of higher fatty acid and amino acid, dialkyl sulfosuccinate ester salt, alkyl sulfosuccinate, naphthenate, etc., alkyl ether carboxylate, acylated peptide, α-olefin sulfonic acid Salt, N-acyl methyl taurine, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, monoglycer sulfate, alkyl ether phosphate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether sulfate ammonium salt, polyoxyethylene alkyl ether sulfate Sodium salt, polyoxyethylene alkylphenyl ether sulfate ammonium salt, polyoxyethylene alkylphenyl ether sulfate sodium salt, polyoxyethylene alkyl sulfate monoethanolamine , Polyoxyethylene alkyl ether phosphate salts, polyoxyethylene alkyl ether phosphate potassium salt, polyoxyethylene alkyl ether phosphate diethanolamine, sodium alkylnaphthalenesulfonate, sodium laurylsulfate.

As the nonionic surfactant, a fluorine-based surfactant, a silicone-based surfactant, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene alkylphenyl ether, sorbitan monostearate. ,
There are acetylene glycol, ethylene oxide adduct of acetylene glycol, propylethanolamide, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and the like.

If the addition amount is too large, the foaming property becomes large, and there is a risk of impairing the ejection stability.
The amount is preferably wt% or less, more preferably 1 wt% or less.

Further, urea, thiourea, ethylene urea and the like can be added for the purpose of preventing nozzle drying.

The ink was manufactured by the following procedure, but the invention is not limited to this.

The colored particles used in this example are the following three types.

Colored Resin Particles A Resin component (polystyrene) and carbon black or organic pigment are sufficiently uniformly mixed, heated and melted and kneaded by using a kneader, a load mill, etc., and after cooling, coarsely cut into a few mm by a hammer mill or a cutter mill. The mixture was pulverized, subsequently added to water containing a dispersant, and finely pulverized with a jet mill to obtain an aqueous colored resin dispersion liquid. After that, undesired dissolved components, undersized particles, and coarse particles are removed by centrifugation and filtration so that the average particle size becomes 0.1 to 10 μm, and the colored fine particles of four colors of yellow, magenta, cyan, and black are dispersed. A liquid was obtained.

Colored Resin Particle B A monomer of a resin component (methyl acrylate or methyl methacrylate) is emulsion-polymerized in water to prepare polymer particles having an average particle size of 0.1 to 5 μm. After that, coarse particles, unreacted monomers, and semi-dissolved particles are removed to obtain an aqueous resin emulsion consisting only of polymer particles having an average particle diameter of 0.1 to 5 μm. After that, the polymer particles in the emulsion are dyed with an oil dye or a disperse dye,
An aqueous colored resin emulsion having four colors of yellow, magenta, cyan and black is obtained.

Colored Resin Particles C A polymerizable monomer (styrene, methyl acrylate) is dissolved or dispersed in a non-aqueous solution in which a non-aqueous solvent is dissolved, and then the polymerizable monomer is suspended. Copolymerize by the turbid polymerization method. By adjusting the concentration of the polymerizable monomer, the reaction temperature, and the reaction time, a colored resin particle dispersion liquid having a desired particle size distribution is obtained. Furthermore, by replacing the solvent from a non-aqueous solvent to an aqueous solvent, yellow, magenta,
A four-color aqueous colored resin particle dispersion liquid of cyan and black is obtained.

The ink is manufactured by the following procedure, but the invention is not limited to this. First, a colored resin particle dispersion liquid, or a surfactant as another additive and a water-soluble organic solvent are added to water and mixed with stirring. It is confirmed by microscopic observation that the monodispersed state has been obtained, and other additives such as a water-soluble polymer and a preservative are added thereto, and further stirred sufficiently to completely dissolve. The dispersion was filtered under pressure with a membrane filter of 5 to 15 μm to remove dust and coarse particles to obtain an ink.

All the physical properties of the above ink examples are adjusted within the following ranges.

The ink viscosity is 25 m in order to ensure stable ejection from the head and stable ink supply to the head.
Pa · sec or less is desirable, and more preferably 15 mPa · sec or less.

The surface tension of the ink is 3 in order to satisfy the water repellency of the nozzle and the spreading and wetting on the recording medium.
0-60 mN / m is preferable.

FIG. 1 shows a first embodiment according to the present invention, and FIG.
The cross-sectional views of the recording method of the second embodiment of the present invention are shown in FIG.

This printer is a printer that expresses full color by using four colors of ink.

As the ink, the ink having the composition shown in Table 1 was prepared. The inks of the respective examples are composed of four colors of ink, black, yellow, magenta and cyan.

[0056]

[Table 1]

First, the first embodiment of FIG. 2 will be described.

An ink jet type recording head 7 is mounted on a carriage device that moves in the axial direction of the platen at a position facing the platen 6, and the platen 6 is in contact with paper pressing rollers 8 and 9 for recording medium. Record paper 11
Along the platen 6.

The platen 6 is formed by laminating silicone rubber or the like as a surface layer on the periphery of an aluminum tube and is rotated by a driving device (not shown).

The recording head 7 is an ink jet recording head of the type using a piezoelectric element, and has color ink nozzles of 32 nozzles for each color for four colors of yellow, magenta, cyan, and black, each of which is arbitrary. Are arranged in a matrix.

Then, each of the nozzles ejects ink by an electric signal from a head driving device (not shown) on the basis of print data given to a computing device (not shown). It should be noted that the ink is supplied from the ink container 71 in which four colors of ink are filled in different chambers.

The paper pressing roller 8 is a rubber roller made of a steel core material made of acrylonitrile rubber.
And is driven by the rotation of the platen 6.

The paper pressing roller 9 is a roller in which nylon threads are planted on a steel core material, and is in light contact with the platen 6 and rotates at a speed slightly higher than that of the platen 6.

Next, the operation will be described. At the start of the printing operation, the recording paper is fed between the platen 6 and the paper pressing roller 8 by a paper feeding device (not shown), and the platen 6 and the paper pressing roller 9 are rotated by a predetermined amount, so that the recording paper 11 is moved to the recording head 7 Located directly under
The recording paper 11 is brought into close contact with the platen 6.

The recording head 7 supplied with the ink from the ink tank 71 selectively ejects ink droplets from its nozzle according to the movement of the carriage and the printing pattern, and writes an ink image on the recording paper 11.

At this time, each ink droplet separates the colored resin particles and the solvent on the recording medium and fixes the colored resin particles, so that the time difference until the next dot is overlapped is at least 2 seconds. As described above, the carriage movement, the ink ejection frequency, and the nozzle arrangement are adjusted.

By repeating a predetermined amount of rotation of the platen 6 and the paper pressing roller 9 and printing by moving the carriage,
After printing on the entire recording paper, the recording paper is discharged to a paper discharge tray (not shown), and the printing is completed.

Next, the second embodiment of FIG. 3 will be described.

According to this method, it is possible to heat the recording medium at the time of writing an image to increase the separation speed between the colored resin particles and the solvent.

A heater 12 is disposed inside the fixed platen 6, and the platen 6 is heated by a temperature sensing means (not shown) and a heater control means (not shown) so that the surface temperature can increase the separation speed of the colored resin particles in the ink and the solvent. The temperature is controlled so that it becomes the temperature. In this embodiment, the temperature of the platen 6 is controlled to be 80 ° C.

Further, in the recording method of this embodiment, an example in which the platen temperature is 80 ° C., the ink ejection frequency is 12 kHz at a carriage moving speed of 510 mm / sec, and the time difference until the next dot is overlapped is 2 sec. However, the present invention is not limited to this, and writing at a higher speed is possible at a higher temperature, and various other combinations are possible. Further, the permeability of the solvent in the ink is affected by the ink components, so that if the ink components are changed, it is necessary to change the combination of temperature and speed.

A preferable platen temperature is to ensure a sufficient writing speed and prevent excessive energy consumption.
The temperature is preferably 50 to 100 ° C, more preferably 50 to 80 ° C.

Next, the third embodiment of FIG. 4 will be described.

The third embodiment is characterized in that the recording image obtained by the method of the first and second embodiments is thermally fixed by another heating means 14. The heating temperature is preferably 10 ° C. to 100 ° C. higher than the Tg (glass transition temperature) of the colored resin particles, the softening temperature or the MFT of the ink,
Furthermore, it is preferable that the temperature is higher by 10 ° C to 80 ° C.

In the apparatus of FIG. 4, the heating means 14 is composed of a metal roll having good thermal conductivity, and the metal roll has a heater 13 disposed therein, and is heated by a temperature sensing means (not shown) and a heater control means (not shown). The temperature is controlled to be the fusion temperature of the colored resin particles in the ink (the fusion temperature of the ink of the present invention was 60 ° C. to 70 ° C.) + 50 ° C. In this embodiment, the temperature of the roll surface of the heating means 14 is controlled to 120 ° C.

Further, in order to prevent the colored resin particles on the recording medium from transferring to the roll side, it is preferable to coat the surface of the metal roll with Teflon resin, silicone resin or the like. Alternatively, a method in which a belt coated with the above resin is rotated, the surface of the belt is brought into contact with a recording medium, and then contact heating is performed with a heating roll is also effective.

As another heating means, as shown in FIG. 5, a recording medium on which an ink image is written is heated in a non-contact manner by radiant heat from a heating means 15 composed of a heater and a reflecting mirror. You may.

The evaluation results of printing according to the present invention are shown in Table 2.

The following items were evaluated as evaluation items.

1) The paper used for the dot diameter variation evaluation depending on the paper type is a paper having different ink permeability.
a. Recycled paper with relatively large ink bleeding among the typical papers on the market, b. Medium bleed copy paper, c. There are three types of inkjet paper that have almost no bleeding. The evaluation was performed by the following level judgment. Among the black ink dots printed on the above three types of paper, ⊚: The dot diameter variation is 25% or less in the range. ◯: The dot diameter variation is 30% or less in the range. ×: The dot diameter variation exceeds 30% in the range.

2) The pattern used for evaluation of dot diameter variation due to color superimposition is a. 1-dot pattern of cyan ink printed as the first color on paper, b. 1-dot pattern of cyan ink printed as a second color on solid printing of yellow ink on paper, c. Solid ink of yellow ink, solid ink of magenta ink are overprinted on paper, and one dot pattern of cyan ink is printed as the third color on it.
The evaluation was performed by the following level judgment. In the three patterns of cyan ink dots, ⊚: The dot diameter variation is 25% or less in the range. ◯: The dot diameter variation is 30% or less in the range. ×: The dot diameter variation exceeds 30% in the range.

In addition to the printing results according to the present invention, the followings were evaluated as comparative examples.

Comparative Example 1: As an ink, an ink containing water, a water-soluble organic solvent, and a water-soluble dye as a main component and having permeability is used, and the same evaluation is performed using the recording method of Example 1. I went.

Comparative Example 2: For the ink, the same dot as that of Ink Example 1 was used, and the next dot was overprinted before the colored resin particles and the solvent in the ink were separated.

[0085]

[Table 2]

According to the print evaluation results, when the ink and recording method of the present invention were used, uniform high image quality of each dot was obtained regardless of the paper type and color overlap.

When the image on which the inks of a plurality of colors are superposed is post-fixed by the heating means, the edges are clarified,
High-definition image quality was obtained by making the dots uniform.

On the other hand, when the ink of Comparative Example 1 was used, the way in which the ink spreads was not uniform depending on the paper type, and the dot diameter varied greatly, causing color misregistration.

When the recording method of the comparative example is used,
Although there was no effect of the paper type, the dot diameter differs depending on the printing pattern when color overlapping is performed, and the dot diameter becomes larger when printing on a solid pattern than when printing on paper. It was

From the above results, by using the ink and recording method of the present invention, it is possible to prevent the ink from mixing and flowing,
Higher image quality is possible by making each dot uniform regardless of paper type and color overlap.

Further, by post-fixing the image in which the inks of a plurality of colors are superposed by the heating means, it is possible to improve the image quality by clarifying the edges and making the dots of each color uniform.

[0092]

According to the present invention, the colored resin particles in the ink are quickly separated from the solvent in the ink on the paper, and after the colored resin particles are fixed and cannot move, another ink is overprinted. By doing so, it is possible to prevent mixing of different inks, flow, etc., and to fix the colored resin particles. Therefore, it is possible to improve image quality by making each dot uniform regardless of paper type and color overlap.

Further, by post-fixing the image on which the inks of a plurality of colors are superposed by the heating means, the edges can be made clearer and the dots of each color can be made uniform, so that the image quality can be improved. You

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a printing principle of ink and a recording method according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an inkjet printer according to a first embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an inkjet printer according to a second embodiment of the present invention.

FIG. 4 is a conceptual diagram showing an inkjet printer according to a third embodiment of the present invention.

FIG. 5 is a conceptual diagram showing an inkjet printer using another heating method according to the present invention.

[Explanation of symbols]

 1: Colored resin particles for the first color 2: Colored resin particles for the second color 3: Colored resin particles for the third color 4: Recording paper surface 5: Solvent penetration 10: 1st color dot 20: 2nd color dot 30: 3rd color Dots 6: Platen 7: Recording head 8: Paper pressing roller 9: Paper pressing roller 11: Recording paper 12: Heater 13: Post heating heater 14: Post heating roller 15: Non-contact heater 71: Ink container

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B41M 5/00 E

Claims (6)

[Claims] 1. An ink containing at least a solvent containing water as a main component and colored resin particles finely dispersed in the solvent, the ink being recorded on a recording medium or an ink recorded on the recording medium. A color inkjet ink, wherein the solvent and the colored resin particles are separated when attached to the colored resin particles. 2. The weight average particle diameter of the colored resin particles is 0.1.
The color inkjet ink according to claim 1, wherein the color inkjet ink has a thickness of ˜5 μm. 3. The specific gravity of the colored resin particles is 0.95 to 1.2.
The color inkjet ink according to claim 1, wherein 4. A color inkjet recording method for forming an ink image by recording ink droplets from a recording head onto a recording medium to record the ink according to claim 1, wherein the ink is selectively discharged according to image data. Then, when forming a color image on the recording medium, after the solvent of the ink previously attached to the recording medium and the colored resin particles are separated, ink droplets of different colors may be ejected at overlapping positions. A characteristic feature is a color inkjet recording method for performing multicolor or multiple printing. 5. The color ink jet recording method according to claim 4, wherein the recording medium is heated by a heating means when a color image is printed. 6. The color inkjet recording method according to claim 4, wherein after the color image is printed, the image is heated and fixed by a heating unit.