JPH04185672A - Ink for ink jet printer and its fixation - Google Patents

Abstract

PURPOSE:To obtain the title ink which does not blot when applied to recording paper and excels in the dispersion stability of the contained colored resin particles during storage, etc., by dissolving a water-soluble compound in an aqueous medium so that a difference in the specific gravity between the medium and the particle may be below a specified value. CONSTITUTION:An ink for an ink jet printer comprising colored resin particles and an aqueous medium in which the particles are dispersible, wherein a water- soluble compound (desirably one having a specific gravity of 1.00 or above, particularly desirably an inorganic salt) is dissolved in the medium so that a difference in the specific gravity between the medium and the particle may be below 0.04. Since the above ink is one in which the colorant is not a conventional water-soluble dye but is the colored resin particles, and these particles are dispersed in the medium, ink dots jetted from the nozzle of an ink jet printer do not blot on recording paper. Since the difference in the specific gravity between the medium and the particle is below 0.04, the dispersion stability of the particles during storage, etc., can be improved, and plugging of an ink jet can be prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an inkjet printer ink and its fixing method, and more specifically, an inkjet printer ink that prevents bleeding when applied to recording paper and its fixing method. Regarding the fixing method.

(Prior art and problems to be solved by the invention) Inkjet recording does not require processes such as development, can use plain paper as a recording medium, is quiet in its printing operation, and can be Can record characters, figures, etc.
It has the characteristic that it can be easily colored.

Traditionally, ink for inkjet printers uses a solution containing dissolved dyes, but when the ink is applied to recording paper, the recorded dots bleed, causing the image to spread and contrast to decrease. It also has the disadvantage that the recorded image lacks water resistance.

For this reason, great efforts are being made to prevent bleeding in inkjet printer inks that use dyes. For example, ■ By combining the types and amounts of water, organic solvents, and water-soluble dyes, The solubility in the solvent is 5% by weight or less, and the content of the solvent is 3 to
30% range (Japanese Unexamined Patent Publication No. 124166/1982), ■ Invention of containing a specific diether compound in the ink (Special Publication No. 321/1988), ■ Invention containing beef sauce or An invention containing an alkylene oxide adduct of the sugar alcohol, a pentose or an alkylene oxide adduct of the sugar alcohol, or an alkylene oxide adduct of glucose (JP-A-62-15272.62-15273.62-15)
274), (2) inventions using water-soluble direct dyes and acid dyes from which surface-active substances have been removed by adsorption resins (Japanese Patent Application Laid-open No. 60-49070), etc. have been proposed.

Although these inventions are effective in reducing the extent of ink smearing on recording paper, they cannot completely prevent the tendency for ink to spread around dots due to the capillary action of the fibers that make up recording paper. is impossible in principle.

Therefore, in Japanese Patent Application No. 2-45685, the present applicant developed an ink made by dispersing colored resin particles in an aqueous medium as an inkjet printer ink that prevents ink dots ejected onto recording paper from smearing. Proposed. When using such ink, the aqueous medium contained in the ink jetted onto the recording paper permeates into the recording paper, but the colored resin particles cannot pass through the pores formed between the fibers of the recording paper. It remains on the recording paper, so the ink dots do not bleed.

In this way, in order to prevent ink bleeding, it is sufficient to make the diameter of the colored resin particles larger than a predetermined diameter, but as the diameter of the colored resin particles increases, the dispersion stability of the colored resin particles during storage decreases. There is a drawback that it does. This is because as the particle size of the colored resin particles increases, the dispersibility due to Brownian motion decreases, so that, for example, if the specific gravity of the colored resin particles is greater than the specific gravity of the medium, they will settle. Furthermore, when the particle size of the resin particles is increased, the permeability into the recording paper decreases, and thus the fixability of the colored resin particles to the recording paper decreases. Therefore,
For example, if a hand or the like touches an image formed on recording paper, there is a risk that the image will be rubbed and become unreadable.

The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to prevent the aqueous medium initially formed on the recording paper from permeating through the recording paper due to capillary action. To provide an ink for an ink jet printer capable of forming an image of high density, high contrast and high resolution without causing any spreading of ink dots, and in which the formed image has excellent water resistance. Another object of the present invention is to provide an ink for inkjet printers that can improve the dispersion stability of colored resin particles during storage of the ink. Still another object of the present invention is to provide a method for fixing ink for an inkjet printer that can improve fixing properties to recording paper.

<Means for Solving the Problems> The ink for an inkjet printer of the present invention contains colored resin particles and an aqueous medium in which the colored resin particles can be dispersed, and the aqueous medium and It is characterized in that the water-soluble compound is dissolved so that the difference in specific gravity of the colored resin particles is 0.605 or less, thereby achieving the above object.

The ink for an inkjet printer of the present invention contains colored resin particles and an aqueous medium in which the colored resin particles can be dispersed, and the aqueous medium contains a water-soluble medium in which the colored resin particles can be dispersed in the aqueous medium. It is characterized by containing a dispersion stabilizer, thereby achieving the above object.

The method for fixing ink for inkjet printers of the present invention includes inkjet printer ink containing colored resin particles having a glass transition point of 10 to 200°C and a medium capable of dispersing the colored resin particles. The above object is achieved by including the steps of forming an image by ejecting it onto recording paper from a nozzle of a printer, and melting the colored resin particles by heating the image with a heating means.

(Function) The ink for inkjet printers of the present invention uses colored resin particles as a colorant instead of conventional water-soluble dyes, and the colored resin particles are dispersed in an aqueous medium. Therefore, the ink dots ejected from the nozzles of the inkjet printer do not smear on the recording paper. The mechanism by which this ink penetrates into the recording paper will be explained with reference to FIG.

In step A of FIG. 1, when ink is ejected in the form of droplets 2 from an inkjet nozzle (not shown) onto the recording paper 1, the droplets 2 collide with the recording paper 1 and form dots, as shown in the step. 5 is formed.

The droplets 2 consist of colored resin particles 4 dispersed in a continuous phase of an aqueous medium 3. Simultaneously with the formation of the dots 5, the aqueous medium 3 is absorbed and permeated in the thickness direction and surface direction of the paper due to the capillary action of the paper, causing the paper to spread, but as shown in step C, the colored resin particles 4 are printed on the paper surface. The dot 5 remains in the shape and maintains the shape of the dot 5. As described above, when the ink of the present invention is used, even if the aqueous medium permeates and spreads through the paper, the occurrence of image bleeding is prevented, and the image formed is made up of colored resin particles deposited on the paper surface and has a pigment effect. Because of this, it has the advantage of high density, high contrast, and excellent resolution. Further, since the formed image is made of resin, it does not dissolve again even when it comes into contact with water, and has water resistance.

In particular, in the present invention, by dissolving a water-soluble compound in an aqueous medium to make the difference in specific gravity between the aqueous medium and the colored resin particles less than 0°04, the dispersion stability of the colored resin particles during ink storage is improved. can do.

In other words, when the specific gravity of the colored resin particles is very large compared to the specific gravity of the aqueous medium, the settling rate of the colored resin particles is determined by Stokes' law, and the colored resin particles settle over time, resulting in uniform dispersibility. However, by setting the specific gravity of the colored resin particles and the specific gravity of the aqueous medium within a predetermined range, sedimentation of the colored resin particles can be prevented, and agglomerates of the sedimented particles can cause inkjet printing. It does not cause clogging.

Furthermore, by containing a dispersion stabilizer in the ink,
In addition to improving the dispersion stability of the ink, it is also possible to improve the fixing properties. This function will be explained based on FIGS. 2(a) and 2(b). As shown in the figures, a part of the dispersion stabilizer 7 is adsorbed on the surface of the colored resin particles 4. Therefore, when this ink is ejected onto the recording paper 1, the dispersion stabilizer 7 has a very high affinity with the recording paper 1, so when the aqueous medium evaporates after image formation, the colored resin particles 4 and the recording paper 1 The dispersion stabilizer 7 acts as a binder between the
The colored resin particles 4 can be firmly fixed onto the recording paper 1.

In the present invention, colored resin particles having a glass transition point of 10 to 200°C are used, and after the ink is ejected onto the recording paper, if the ink is heated by a heating means, the colored resin particles contained in the ink are heated and melted. By allowing the colored resin particles to penetrate between the fibers of the recording paper and fusing the colored resin particles to each other, the fixability to the recording paper can be further improved.

<Preferred Embodiment of the Invention> The colored resin particles used in the present invention can be produced, for example, according to the following method.

First, as shown in step A in FIG. 3, a bimarunion in which spherical resin particles 4A are dispersed in an aqueous medium 3 is formed by an emulsion polymerization method or a dispersion polymerization method.

The particle size of the resin particles 4A is preferably controlled to be submicron. Then, as shown in the process steps,
A dye 6 such as a disperse dye is added to this emulsion to dye the resin particles A.

In this way, as shown in Step C, colored resin particles 4 having substantially all of the dye dyed are formed, and this dispersion can be used as an inkjet printer ink as it is or after performing various operations necessary for ink production. use.

These resin particles are, for example, emulsion polymer particles formed by an emulsion polymerization method or post-emulsification (phase inversion method) of a polymer, or dispersion polymerization method, in which the monomer is dissolved but the resulting polymer is For the coalescence, dispersed polymer particles obtained by polymerizing monomers in a solvent in which they do not dissolve can be used.

The particle size of these resin particles is preferably micron size or h-submicron size from the viewpoint of dispersion stability and prevention of nozzle clogging, but the median diameter according to the Coulter Counter method is preferably 0.01 to 20 μm. In particular, it is preferably in the range of 0.05 to 5 μm.

The particles of the emulsion polymer or the dispersion polymer can be produced by any method known per se, except that the particle size is adjusted within the above-mentioned range. For example, in the emulsion polymerization method, monomers are emulsified and dispersed in an aqueous medium to micron size or submicron particle size using an emulsifier such as a surfactant, and emulsion polymerization is performed in the presence of a radical polymerization initiator. In the dispersion polymerization method,
The monomers are polymerized in an organic solvent that dissolves the monomers but not the resulting polymer. In this dispersion polymerization method, in order to improve the dispersibility of the produced colored resin particles, it is preferable to use a dispersant or a combination with a dispersion aid.

In order to produce an emulsion polymer by post-emulsification (phase inversion method), a melt or solution of the polymer and an aqueous medium containing an emulsifier are kneaded, if necessary, at high temperature and high pressure to form a polymer. A method of inverting the phase from a continuous phase to a dispersed particle phase can be used, and this method is suitable for producing emulsion polymers from polymers other than radical polymerization types.

The above polymers include polyethylene, polypropylene,
Olefin resins and olefin copolymers such as ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, and ionomers, vinyl aromatic hydrocarbon polymers such as polystyrene and styrene copolymers, (meth)acrylic acid ester polymers, etc. Acrylic polymers such as polymers; vinyl chloride polymer polyamides, polyesters, polyvinyl acetal resins, nivoxy resins, phenol resins, and the like.

In the present invention, it is particularly preferable to use an emulsion polymerization method or a dispersion polymerization method in order to produce resin particles that are fine and uniform in particle size. Hydrocarbons and (meth)acrylic acid esters are preferred.

Vinyl aromatic monomers include the formula (wherein R1 is a hydrogen atom, a lower alkyl group, or a halogen atom, and R2 is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, a nitro group, or vinyl group), such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, 0-1m-1p-chlorostyrene, p-ethylstyrene, and divinylbenzene alone. Or a combination of two or more types can be mentioned.

In the formula, R3 is a hydrogen atom or a lower alkoxyl group, R4 is a hydrogen atom, a hydrocarbon group having up to 12 carbon atoms, a hydrocyalgyl group, or a vinyl (meth)acrylic acid ester monomer. Acrylic it represented by ester group)
Examples include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl acrylate, acrylic acid/chloromethane, phenyl acrylate, methyl methacrylate, methacrylate, and methacrylate. Examples thereof include 2-ethyl acid-beef sil, β-hydroethyl bovine methacrylate, γ-propyl hydroxyacrylate, butyl δ-hydroxyacrylate, ethyl β-hydrobovine methacrylate ethylene glycol dimethacrylate, and the like.

These oil-soluble monomers can be used alone or in combination of two or more, and can also be used for the purpose of modifying the resin particles, such as improving dyeability or water dispersion stability. It is also possible to copolymerize small amounts of, for example 1 to 30% by weight, in particular 2 to 20M11%, based on the total.

This water-soluble monomer has a small number (or one) of anionic groups such as sulfonic acid, phosphoric acid, and carboxylic acid type, and these acid groups can be used in the form of alkali metal salts such as sodium salts, ammonium salts, etc. , even in the form of salts such as amine salts.
! It may also be in the form of M acid. Suitable examples thereof are styrene sulfonsane, sodium styrene sulfonate, 2-acrylamido 2-methylpropanesulfonic acid, 2-acid phosphooxy/ethyl methacrylate, 2-anrad phosphooxy/ethyl methacrylate, 3-r:! o2-andphosphooxybrobyl methacrylate, acrylic acid, methacrylic acid, fumaric acid, crotonic acid, tetrahydroterephthalic acid, itaconic acid, maleic acid, and the like.

As the emulsifier, any anionic or nonionic surfactant known per se can be used,
This emulsifier is present in the system from O to 101! ffi%, especially in a concentration of 0 to 5% by weight.

In this case, if the emulsifier is present in excess in the system, it will cause clogging of the inkjet nozzle, so it is preferable that the emulsifier concentration is within a limit that maintains the dispersion stability of the resin particles. If the surface active substance is strongly adsorbed on the surface of the resin particles, it is not necessary to add an emulsifier.

The weight ratio of the monomer to the aqueous medium is generally 1=99 to 50:50.

Examples of polymerization initiators used in dispersion polymerization include azo compounds such as azobisisobutyronitrile, cumenehydroboro, t-butyl hydroperoxide, dicumyl peroquinde, and di-t-butyl peroquine. Those soluble in oil-soluble monomers such as peroxides can be used. Potassium persulfate, sodium persulfate, azobisisobutyroamide hydrochloride, azobisisobutyroamide nitrate, and the like are used as initiators for emulsion polymerization. In addition, combinations of ionizing radiation such as 7-rays, accelerated electron beams, ultraviolet rays, and various photosensitizers may also be used.

The amount of the polymerization initiator such as an ab compound or peroxide may be a so-called catalytic amount, and is generally preferably used in an amount of 0.1 to 10% by weight based on the monomers charged. The polymerization temperature and time may be those known in the art, and generally polymerization at a temperature of 40 to 100°C for 1 to 50 hours is sufficient.

Note that the reaction system may be stirred at a gentle level so that a homogeneous reaction occurs as a whole.Also, in order to prevent the polymerization from being inhibited by oxygen, the reaction system may be replaced with an inert gas such as nitrogen to carry out the polymerization. You can.

In the case of the dispersion polymerization method, the organic solvents used include lower alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone, and methyl butyl ketone; ethers such as tetrahydrofuran and dioxane; and esters such as ethyl acetate. Amides such as dimethylformamide are appropriately selected and used depending on the type of monomer used. These organic solvents can also be used in combination with water for the purpose of controlling precipitation of resin particles.

In addition to the above-mentioned surfactants, for the purpose of increasing the dispersion stability of resin particles, polymeric dispersion stabilizers such as polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, etc. meth)acrylic acid-(meth)acrylic acid ester copolymer, acrylic acid-vinyl ale copolymer, methacrylic acid-styrene copolymer, carboxymethylcellulose, polyethylene oxide, polyacrylamide, methylcellulose, ethylcellulose, polyvinyl alcohol, etc. It can also be used.

The dye used for dyeing the resin particles needs to be a water-insoluble dye from the standpoint of selectively dyeing the resin particles. Examples of the water-insoluble dye include disperse dyes, water-insoluble metal-containing dyes, vat dyes, and oil-soluble dyes.

Among these, disperse dyes are particularly desirable in terms of good dyeability. Water-soluble dyes such as acid dyes, provided, of course, that there are no appreciable amounts of dissolved dye in the aqueous medium.
Cationic dyes, basic dyes, etc. may also be used. ] of the dye used is generally 0.1 to 20% by weight based on the resin particles.
, particularly preferably in the range of 1 to 10% by weight.

When dyeing resin particles, add to the aqueous dispersion of resin particles,
The dye described above is added to dye the resin particles, but the treatment may be carried out at a temperature that does not cause coalescence of individual resin particles. This treatment temperature varies depending on the type of polymer and the type of dye, but is generally lower than the softening point of the resin particles +40°C.

The glass transition point of the colored resin particles thus obtained is preferably 10 to 200°C, more preferably 30 to 7°C.
It is 0°C. In the present invention, it is also possible to use resin particles having a glass transition point lower than that of toner particles obtained by the conventional Carlson method. This makes it possible to use even resins such as

The ink for inkjet printers of the present invention generally contains colored resin particles dispersed in an aqueous medium in an amount of from 1 to 50% by weight, particularly from 5 to 25% by weight, based on the total amount.

As the aqueous medium, water or a mixed medium of water and a water-soluble organic solvent can be used, and examples of the organic solvent include the organic solvents used in the dispersion polymerization method described above.

Furthermore, in addition to the above aqueous medium and colored resin particles, the ink of the present invention also contains desirable components for dispersion, such as an emulsifier, a dispersion stabilizer, and a dispersion stabilizing aid derived for preparing a dispersion, and the ink. may contain desirable ingredients. As the dispersion stabilizer, the above-mentioned water-soluble dispersion stabilizers can be used. For example, when polyvinyl alfur, sodium polyacrylate, starch, cellulose, polyethylene oxide, etc. are used, the fixability of colored resin particles to recording paper is improved. can also be improved. When this water-soluble dispersion stabilizer is used to improve fixing properties, the amount thereof is preferably 10 to 200% by weight based on the resin particles.

Further, as the water-soluble compound soluble in the aqueous medium used to reduce the difference in specific gravity between the colored resin particles and the aqueous medium, both inorganic compounds and organic compounds can be used. This water-soluble compound preferably has a specific gravity of 1.00 or more when made into an aqueous solution. Examples of the inorganic compound include the following, with inorganic salts being particularly preferred.

AgNOs, AlCl3. AIK(SOJ2.
AIN)I4(sOd2. Al(NO3)31
Al2(SOJ)3. AS203. BaC
1z, Ba(NO3)2. BeCl2, B
e(NOa)2. BeSO4, Br2. CaB
r2. CaCl2. Ca12゜Ca(NO3)
2. Ca(OH)2. CaSO4, CdCl2
．． Cd(NOi)2. Cd50a, Ce2
(SOa)s, COCl2. Co(NO3)2
．． C03Oa, CrCl3, Cr(NO3
)3. CrO3, Cr2(SO4)3. C52
SO,,CuCl2°Cu(NO3)2. CuS
O4, FeCl2. FeCl3. Fe(N
O3)3. FeSO4, Fe2(SOa)3.
B3ASOA, H3BO3,)IBr, HC
I, HCl031 HCl041 8F, old,
)+103. HIOA, HNO3, H2O2
, H3P0A, H2SO3, H2S203. H
2Se0a, H2S1Fa, H2SO4,H2
SO4/HNO3 mixed acid, t(gcI2.KBr
, KBrO3, KCI, KClO3゜KCrO
a, )FCN, )F2CO3,K2S1Oa,
K2Cr2O7, KCr(SOa)2, KF,
KFe(SO4)2. K3Fe(CN)s,
K4Fe(CN)a, KHCO3, KH2PO4,
KHSO4, Kl, K103. KMnO4, 2M0OA, KSCN, KNO2, KNOs,
KOH, K2S, KSH, K2SOs, K
2S0t.

K2S1Oa, K2WO4, La(NO3)2.
LiBr, LiC1, Lit, LiNO3,
LiOH, Li25Oa, MgBr2. MgC
+2. Mgh, Mg(N.

3)2. Mg5Oa, MnCl2.
Mn(NO3)2. Mn5Oa, NH20
FI, NH2OH-HCl, NH3,NHa
Br, (NHa)2cO3, NHaCl, (N
H4) Cr(SOa>2.NHaF, (NL)
Fe(SOa)2. (NHa)2Fe(SOa)2
．． N) lzl, NHaSCN, NHtNO
3+ (NHahSOa, Li14. N2H
t-2Hcl, Na5AsOt, NaBO2,
Na2BaOt, NaBr, NaBrO3,N
aCl, NaClO3, NaCl0a, Na2
CO3, Na2CO3, Na2crOj, Na2
Cr20), NaF, Na2HAsOa,
Na) I2PO4, Na2HPOa, NaH
SOa, Nal, Na25nOa, NaN
O2, NaN0z, Nao)I, NaPO3,
Na3PO4, NaCl0a, Na2S, Na
5CN, Na2S2O3, Na2SO3, Na25
Dt, Na25nOa, Na2WOa, N
iCl2, Ni(NO3)2. N15Oa,
Pb(NOs)2. PtC1a, RbNO3
゜Rb0)I, Rb2SO4,5nC12,5nC
14, SrCl2. 5r(NOs)2゜ThCla,
Th(NO3)4. TI (NO3)2. T
l2SO4, UO2(NO3)2゜WO3(H2LO+
3), ZnCla, Zn(NOs)2. Zn
5Oa, water glass, milk of lime.

One or more water-soluble compounds may be used in combination.

By dissolving these water-soluble compounds in an aqueous medium, the specific gravity of the aqueous medium can be increased, thereby reducing the difference in specific gravity between the colored resin particles and the water-soluble medium and improving dispersibility. .

Furthermore, the ink of the present invention may include, for example, ethylene glycol, for the purpose of increasing the wettability and rewetability of the colored resin particles.
It may contain glycerin, various polyhydric alcohols, etc. Furthermore, in order to sequester metal ions mixed into the ink, various metal sequestering agents such as oxidizing agents are added, and in order to improve the shelf life of the ink and images, various bactericidal agents, antifungal agents, fragrances, Ultraviolet absorbers, acid inhibitors, etc. may be added.

Typical formulation examples (by weight) of ink are shown below.

Colored resin particles 10-30 parts by weight Surfactant 0.05-1 Water-soluble polymer dispersant 0.01-20 Polyhydric alcohol
10-20 // Chelating agent 05-1
〃Mildewproofing agent 01-05 //Water-soluble compound 2-30 ~Water
50 to 200 Next, the ink fixing method of the present invention will be explained. As mentioned above, the glass transition point of the colored resin particles used in this method is 1.
Preferably 0 to 200°C, more preferably 30 to 70°C
It is ℃.

As the heating means used in the present invention, known heating means such as a heat roller and a flash can be used. By heating the ink ejected onto the recording paper by the heating means, the resin particles are melted and penetrated between the fibers of the recording paper, and the resin particles are fused together to form the recording paper. It is possible to improve the fixing properties of

(Effects of the Invention) According to the present invention, by using colored resin particles as a coloring agent for inkjet printer ink, a recorded image with high density, high contrast, and high resolution can be formed while preventing bleeding of ink dots. Moreover, the images formed have the advantage of being excellent in water resistance and fixing properties. Furthermore, the dispersion stability of the ink can be improved to prevent clogging, and the improved image fixing properties prevent the image from becoming blurred due to rubbing or the like.

(Example) Hereinafter, the present invention will be explained in more detail based on examples.

5 points of isopropyl alcohol in a separable flask
00g, 170g of styrene, and 5g of 2,2-azobisisobutychnitrile were charged, and the stirring speed was 100r.
pl, reacted at 70°C for 18 hours, and the volume average particle size was 3.
Resin particles of μm were obtained. Anthraquinone black disperse dye (BASF Palanil Black) was added to this flask.
k FD-BS) was dispersed and dyed at 80°C for 5 hours. This emulsion was filtered to obtain black resin particles.

The above black particles (density = approximately 1.05) log and 1 g of tricalcium phosphate powder were dispersed in 90 g of an 8% by weight aqueous sodium chloride solution (density = approximately 1.05) to obtain an ink for an inkjet printer.

When this ink was printed using an inkjet printer with a nozzle diameter of 70 μm, no bleeding occurred at all.

Further, although this ink was left to stand for 24 hours, no sedimentation of particles was observed.

1 dish, 5 λ, 90 g of water, high molecular weight polyvinyl alcohol (GL-03 manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., polymerization degree of 1500 or more,
1 g of partially saponified product) and low molecular weight polyvinyl alcohol (
Nihon Kagaku Kogyo (manufactured by NHK Co., Ltd. GH-17, degree of polymerization 1000)
After completely dissolving 20 g of the partially saponified product, log of the black resin particles synthesized in Example 1 were dispersed to obtain an ink for an inkjet printer. When this ink was printed using the printer used in Example 1, no bleeding occurred at all.

Furthermore, even if the printed characters were rubbed by hand after they had dried, the characters were not disturbed at all.

Tomo Superintendent ■ 4 pieces of isopropyl alcohol in A's separable flask
00g, water 150g, styrene 1.30g, 2-
40 g of ethylhexyl methactulate, 1 g of divinylbenzene and 5 g of 2,2'-azobisisobutyronitrile were charged, stirring speed was 1100 rpm, and the mixture was heated at 70°C.
After reacting for 8 hours, resin particles having a volume average particle size of 3 μm were obtained. In this flask, add 15 g of ab-based black disperse dye (SPRBlack 1200 manufactured by Mitsui Toatsu Dye Co., Ltd.)
was dispersed and dyed at 80°C for 5 hours. This emulsion was filtered to obtain black resin particles. T of this resin particle
g was measured with a differential scanning calorimeter (DSC) and found to be 63°C.
Met.

10 g of the above black particles and 1 g of sodium dodecylbenzene sulfate were dispersed and dissolved in 90 g of water to obtain a black ink for an inkjet printer. When this ink was printed with the printer used in Example 1, no bleeding occurred.

The images of documents printed with the above ink did not appear distorted under normal usage conditions, but if the printed characters were rubbed vigorously with one's fingers, they became faded. However, this document cannot be fixed at a fixing temperature of 180''.
When I applied it to a heat fixing machine (C), the letters remained clear even if I rubbed them strongly with my fingers.

4. Important words B Figure 1 is a diagram for explaining the functions of the ink for inkjet printers of the present invention, and Figures 2 (a) and (b) are diagrams for explaining the effect of improving fixing properties by a dispersion stabilizer. diagram,
FIG. 3 is a diagram for explaining the manufacturing process of the ink for an inkjet printer of the present invention.

that's all

Claims (1)

[Scope of Claims] 1. An ink for an inkjet printer containing colored resin particles and an aqueous medium in which the colored resin particles can be dispersed, the aqueous medium and the colored resin An ink for an inkjet printer, characterized in that a water-soluble compound is dissolved so that the difference in specific gravity of particles is less than 0.04. 2. An ink for an inkjet printer containing colored resin particles and an aqueous medium in which the colored resin particles can be dispersed, the ink being water-soluble in which the colored resin particles can be dispersed in the aqueous medium. An inkjet printer ink characterized by containing a dispersion stabilizer. 3. An ink for an inkjet printer containing colored resin particles having a glass transition point of 10 to 200°C and a medium capable of dispersing the colored resin particles is ejected onto a recording paper from a nozzle of an inkjet printer to produce an image. 1. A method for fixing an ink for an inkjet printer, the method comprising the steps of: forming an image; and melting the colored resin particles by heating the image with a heating means.