JP2003127518A - Method for ink jet recording, recording unit and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for ink jet recording capable of affording a stable and highly minute image by improving ink storage stability, bleeding resistance, stability (rub resistance or the like) after printing and smoothness, suppressing the deformation of a recording medium and obtaining the good image irrespective of the type of the medium (particularly the medium having no ink absorbability) and to provide a recording unit and an ink jet recorder. SOLUTION: The method for ink jet recording comprises the steps of imparting any injection energy to an ink composition containing a photopolymerizable compound, a photopolymerization initiator and a coloring agent to inject an ink liquid droplet to form the image, fixing the image on the recording medium and then irradiating the image with an ultraviolet ray. In this method, the ink composition contains 100 to 10,000 ppm of a polymerization inhibitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method, a recording unit and an ink jet recording using an ink composition suitable for recording on a recording medium regardless of the type of the recording medium such as paper, plastic film and metal. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, a water-soluble liquid ink composition has been widely used as an ink composition for ink jet recording (hereinafter, also simply referred to as an ink composition or an ink).

Further, a hot-melt type ink composition made of a wax or the like which is solid at room temperature is used to liquefy by heating or the like, to be jetted by applying some energy, to be cooled and solidified while adhering to a recording medium to be recorded. A hot melt type ink jet recording method for forming dots has been proposed.

Since this ink is solid at room temperature, it does not become dirty during handling, and since the amount of evaporation of the ink when melted can be minimized, the nozzle is not clogged.

Further, since it solidifies immediately after being attached, there is no bleeding, and various recording media such as Japanese paper, drawing paper, postcards, and plastic sheets can be used without pretreatment.

US Pat. Nos. 4,391,369 and 4,484,948 describe ink compositions that provide good print quality regardless of paper quality.

Further, Japanese Patent Application Laid-Open No. 56-93776 discloses an ultraviolet curable resin type ink composition having good adhesiveness to a metal surface, and further ink jet recording ink which is cured by exposure to ultraviolet rays. As
As disclosed in US Pat. No. 4,228,438, an ink using an epoxy-modified acrylic resin and a urethane-modified acrylic resin as a binder and using a pigment having a particle diameter of 5 μm or less as a coloring component, Ink using a cationically polymerizable epoxy resin as a binder, which is disclosed in JP-A-58-32674, and using a water-soluble or water-insoluble dye, as described in JP-A-5-186725. There is a disclosure that facilitates printing on plain paper and recycled paper.

However, when an aqueous ink is used for printing,
In particular, it is difficult to print on a recording medium that does not absorb ink, a large ink drying device is required even when using special paper, and high-definition printing is difficult due to bleeding problems and resolution is limited. There are limited uses.

The hot-melt type ink using wax can print on a recording medium having no ink absorbency, and high-speed printing is possible, but the abrasion resistance is very low and the reliability after printing is high. It was difficult to get sex. In addition, the ink adhering to the subject rises and it is difficult to improve the image quality.

The method of curing the recording liquid with light such as ultraviolet rays enables printing on a recording medium having no ink absorption, but high-definition printing is difficult due to the problem of bleeding due to insufficient curing speed, resulting in a high resolution. There was a limit.

Further, there are problems that it is difficult to store the ink for a long time, the head is apt to be clogged due to the curing of the ink in the head portion, and furthermore, the recording medium is heated by the irradiation of ultraviolet rays.

Since the ink jet recording method using an organic pigment as a colorant has many advantages over the ink jet recording method using a dye especially in terms of light resistance, OA
Not only equipment, office printers such as general household printers and facsimiles, but also indoor and outdoor posters, large signboards,
It is expected to find applications in cars, glass, elevators, wall and building decoration, and even printing on cloth.

Therefore, since the ink jet recording method using the organic pigment is excellent in light resistance, the ink storage stability, bleeding resistance, stability after printing (rubbing resistance) and smoothness are also improved. However, the deformation of the recording medium is suppressed, and a good image can be obtained regardless of the type of the recording medium such as paper, plastic film, or metal (especially the recording medium having no ink absorption), and a stable and high-definition image can be obtained. There has been a demand for an ink jet recording system capable of printing the.

[0014]

The present invention has been made in view of the above problems, and improves ink storage stability, bleed resistance, stability after printing (rubbing resistance, etc.), and smoothness, Deformation of the recording medium is suppressed, good images can be obtained regardless of the type of recording medium such as paper, plastic film, metal (especially recording medium that does not absorb ink), and stable high-definition images can be printed. An object is to provide an inkjet recording method, a recording unit, and an inkjet recording device.

[0015]

The above object of the present invention can be achieved by the following constitutions.

1. An image is formed by ejecting ink droplets by applying some ejection energy to an ink composition containing a photopolymerizable compound, a photopolymerization initiator and a colorant,
An inkjet recording method of irradiating an ultraviolet ray after fixing an image on a recording medium, wherein the ink composition contains 100 to 10,000 ppm of a polymerization inhibitor.

2. 2. The inkjet recording method as described in 1 above, wherein the colorant is a pigment, and the amount of the pigment added is 0.5 to 30 mass% with respect to the total ink composition.

3. 3. The inkjet recording method as described in 1 or 2 above, wherein the pigment is a dispersion, and the average dispersion particle diameter of the dispersion is 200 nm or less.

4. 4. The ink jet recording method according to any one of 1 to 3, wherein the photopolymerization initiator is contained in an amount of 0.1 to 20 mass% with respect to the total ink composition.

The viscosity of the ink composition at 5.30 ° C. is 40 to 500 mPa · s.
5. The inkjet recording method according to any one of items 4 to 4.

6. After heating the ink composition at 40 to 150 ° C., by applying some ejection energy, ink droplets are ejected onto the recording medium to form an image.
6. The inkjet recording method according to any one of 1 to 5 above, wherein an actinic ray is applied after the image is fixed on the recording medium kept at -40 ° C.

7. Total amount of ultraviolet light to be irradiated is 10 to 1000
7. The inkjet recording method described in any one of 1 to 6 above, wherein the inkjet recording method is 0 mJ / cm ² .

8. 8. The inkjet recording method according to any one of 1 to 7 above, wherein an ink droplet formed by an inkjet method is attached to a recording medium for recording.

9. 9. The inkjet recording method according to any one of 1 to 8 above, wherein the inkjet recording method is a recording method utilizing a piezoelectric action of a piezoelectric body.

10. 10. The inkjet recording method described in any one of 1 to 9 above, wherein the recording medium has no ink absorbability.

11. A recording unit having an ink containing portion containing ink and a head portion for ejecting ink as ink droplets, wherein the inkjet recording method described in 9 or 10 is used.

12. 12. The recording unit as described in 11 above, wherein the head section discharges ink by a method using a piezoelectric action of a piezoelectric body.

13. An ink jet recording apparatus, wherein the recording unit described in 11 or 12 includes a unit for irradiating ultraviolet rays.

The present invention will be described in more detail below. First,
The polymerization inhibitor will be described.

Examples of the polymerization inhibitor of the present invention include p
-Methoxyphenol, hydroquinone, methoxybenzoquinone, phenothiazine, catechols, alkylphenols, alkylbisphenols, zinc dimethyldithiocarbamate, copper dimethyldithiocarbamate,
Examples thereof include copper dibutyldithiocarbamate, copper salicylate, thiodipropionates, mercaptobenzimidazoles, phosphites, and the like, with p-methoxyphenol, catechols, and phenols being particularly preferable.

Examples of catechols include pt-butylcatechol. Further, as the phenols, 2,6-di-t-butylphenol, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,3 5-di-t-butyl-4-hydroxy-hydrocinnamide), 2,2 ′ methylenebis (4-methyl-)
6-t-butylphenol), 4,4'methylenebis (2,6-di-t-butylphenol), 4,4'butylidenebis (3-methyl-6-t-butylphenol), 2,6-bis (2'- Hydroxy-3′-t-butyl-5′-methylbenzyl) 4-methylphenol,
1,1,3-Tris (2'-methyl-5'-t-butyl-4'-hydroxyphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3'-5'- The-t-
Butyl-4'-hydroxybenzyl) benzene, triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythrityl tetrakis [3- (3,5-di- t-
Butyl-4-hydroxyphenyl) propionate],
2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate and the like can be mentioned, and it is preferably oil-soluble in the present invention.

The polymerization inhibitors may be used alone or in combination of two or more kinds. The amount of the polymerization inhibitor added is 100 to 10,000 ppm, preferably 300 to 2000 ppm, and more preferably 500 to 10,000 with respect to the total mass of all inks.
1,000 ppm is more preferable.

If it is less than 100 ppm, the effect of the present invention cannot be sufficiently obtained, and if it exceeds 10,000 ppm, it causes a color stain.

In the ink jet recording method of the present invention, after heating the ink of the present invention at 40 to 150 ° C., by applying some ejection energy, ink droplets are ejected onto a recording medium to form an image, and 15 After fixing the image on the recording medium kept at -40 ° C, it is preferable to apply actinic rays. Here, the actinic ray refers to ultraviolet rays.

Further, in the present invention, applying some jetting energy to the ink composition is preferably a method of applying energy by the piezoelectric action of the piezoelectric material in the present invention. In addition, for example, bubbles are generated by heat. There is a bubble jet (registered trademark) method in which the injection energy is applied by generating.

The temperature of the ink when ejecting the ink droplets is 40 to 150 ° C., more preferably 50 to 150 ° C.
It is 100 ° C. If the temperature is lower than 40 ° C or higher than 150 ° C, injection becomes difficult. Further, the temperature of the recording medium on which the ink droplets are ejected to form an image is preferably 15 to 40 ° C. If the temperature exceeds 40 ° C., the deterioration of image bleeding is large.

In the present invention, as described above, as a driving force (energy) for ink ejection of an ink jet printer, there is a system utilizing the piezoelectric action of a piezoelectric body capable of high-speed ejection, which has a wide range of application to ink. preferable. The method is specifically, for example, Japanese Patent Publication No. 4-48622.
As described in No. 3, the ink jet head method is one in which an electrode film is formed inside a fine groove formed on a piezoelectric substrate and is covered with an insulating film to form an ink flow path.

The ink jet recording method of the present invention is characterized in that after the ink composition is adhered to the recording medium, it is irradiated with ultraviolet rays. The UV irradiation is performed by jetting ink droplets, then irradiating UV rays having a wavelength of 340 to 380 nm for 0.1 to 10 seconds, and then 280 to 340.
It is more preferable to irradiate with ultraviolet rays having a wavelength of nm for 10 to 1000 seconds.

When UV irradiation is performed, the total UV irradiation amount is preferably 10 to 10000 mJ / cm ² , and more preferably 100 to 1000 mJ / cm ² .

Examples of the ultraviolet irradiation include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low pressure mercury lamps and high pressure mercury lamps.
For example, Fusion System H lamp, D
A commercially available lamp, V lamp, or the like can be used.

The metal halide lamp has a continuous spectrum as compared with a high pressure mercury lamp (main wavelength is 365 nm), has a good luminous efficiency in the range of 200 to 450 nm, and has a good luminous efficiency even in a long wavelength region. is there. Therefore, when a pigment is used in the ink composition of the present invention, a metal halide lamp is suitable.

The timing of irradiating the ultraviolet rays is preferably 0.1 to 100 seconds after the ink droplets are jetted. More preferably, after 1 to 10 seconds.

The wavelength of ultraviolet rays can be controlled by transmitting ultraviolet rays through a film containing an ultraviolet absorber or the like. Examples of the ultraviolet absorber include salicylic acid-based compounds such as salicylic acid phenyl ester, salicylic acid p-tert-butylphenyl ester, and salicylic acid p-octylphenyl ester.

A recording medium having no ink absorbability, a recording medium having low ink absorbability or an ink non-absorbent recording medium means a substrate having no ink absorbability, a substrate having poor ink absorbability and an ink non-absorbent material. A recording medium having a recording medium, a recording medium having a surface layer (printing layer) made of a material having a low ink absorbing property (or a material having a low ink absorbing property) having no ink absorbing property, and a material having no ink absorbing property. A material with low absorbency (or ink non-absorbent material) is, for example,
Various types of plastics and metals.

The photopolymerizable compound and photopolymerization initiator in the ink composition of the present invention will be described. The photopolymerizable compound is a radically polymerizable compound, for example, JP-A-7-1599.
No. 83, Japanese Patent Publication No. 7-31399, JP-A No. 8-2249.
82, JP-A-10-863, Japanese Patent Application No. 7-23144.
No. 4, etc. and a photo-curable material using a photo-polymerizable composition described in Japanese Patent Application No. 7-231444 and a cationic photo-curable resin are known. Recently, a photo-cationic polymerization type photo-curable resin sensitized to a long wavelength region longer than visible light is also disclosed in, for example, JP-A-6-43633.
And Japanese Patent Laid-Open No. 8-324137.

The radically polymerizable compound is a compound having a radically polymerizable ethylenically unsaturated bond, and may be any compound as long as it has at least one radically polymerizable ethylenically unsaturated bond in the molecule. Often,
Those having chemical forms such as monomers, oligomers and polymers are included. The radical-polymerizable compound may be used alone, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve target properties.

Examples of the radically polymerizable compound having an ethylenically unsaturated bond include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid, and salts and esters thereof.
Radical polymerizable compounds such as urethane, amide and anhydride, acrylonitrile, styrene, and various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated urethanes can be mentioned.

Specifically, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, benzyl acrylate, bis (4-acryloxypolyethoxyphenyl) propane, Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate. , Pentaerythritol tetraacrylate, Acrylic acid derivatives such as pentaerythritol tetraacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, N-methylol acrylamide, diacetone acrylamide, epoxy acrylate, methyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate. , Lauryl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, 1,6-hexanediol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, Trimethylol ethane trimethacrylate, trimethylol propane trimethacrylate, 2,2-bis (4-methacryloxy polyethoxy phenyl) methacrylamide derivatives such as propane, other, allyl glycidyl ether, diallyl phthalate,
Examples thereof include derivatives of allyl compounds such as triallyl trimellitate, and more specifically, Shinzo Yamashita, "Handbook of Crosslinking Agents", (1981, Taiseisha); Kiyomi Kato,
"UV / EB Curing Handbook (Raw Materials)" (1985)
Year, Polymer Society); Edited by Radtech, “UV / E”
Application and Market of B Curing Technology ", p. 79, (1989, CMC); Eiichiro Takiyama," Polyester Resin Handbook ", (1988, Nikkan Kogyo Shimbun), etc., or known in the industry. Radical polymerizable or crosslinkable monomers, oligomers and polymers can be used.

The amount of the radically polymerizable compound added is preferably 1 to 97% by mass, more preferably 30 to 9%.
It is 5% by mass.

As a radical polymerization initiator, Japanese Examined Patent Publication No. S59
-1281, Japanese Patent Publication No. 61-9621, and JP-A-6-6
Triazine derivatives described in each publication such as 0-60104,
JP-A-59-1504 and JP-A-61-243807
Organic peroxides described in each publication such as Japanese Patent Publication No. 43-23
684, Japanese Patent Publication No. 44-6413, Japanese Patent Publication No. 44-64
No. 13 and Japanese Patent Publication No. 47-1604, and diazonium compounds described in US Pat. No. 3,567,453, US Pat. Nos. 2,848,328, 2,852,379, and No. 2,940,853, organic azide compounds described in each specification, JP-B-36-2206
No. 2, JP-B-37-13109, JP-B-38-180
No. 15, Japanese Patent Publication No. 45-9610 and other ortho-quinone diazides, Japanese Patent Publication No. 55-39162,
JP-A-59-14023 and other publications and "Macromolecules", No. 10
Vol. 1, p. 1307 (1977), various onium compounds, azo compounds described in JP-A-59-142205, JP-A-1-54440, EP 109,851, and EP 126. , 712
No. etc., each statement, "Journal of Imaging
Science (J.Imag.Sci.) ", Volume 30,
Metal allene complexes described on page 174 (1986), Japanese Patent Application No. 4-56831 and Japanese Patent Application No. 4-89535.
(Oxo) sulfonium organoboron complex described in JP-A No. 61-151197, titanocene described in JP-A-61-151197, and "Coordination Chemistry R".
84), pages 85-277 (19).
1988) and transition metal complexes containing a transition metal such as ruthenium described in JP-A-2-182701, 2,4,5-triarylimidazole dimer described in JP-A-3-209477, tetra Carbon bromide and JP-A-59-1
Examples thereof include organic halogen compounds described in JP-A-07344. These polymerization initiators are added in an amount of 0. 0 with respect to 100 parts by mass of the compound having a radically polymerizable ethylenic unsaturated bond.
It is preferably contained in the range of 01 to 10 parts by mass.

As the cationic polymerization type photocurable resin, an epoxy type UV curable prepolymer of a type (mainly an epoxy type) in which polymerization is caused by cationic polymerization, and a monomer has two or more epoxy groups in one molecule. The prepolymer contained can be mentioned. Examples of such prepolymers include alicyclic polyepoxides, polyglycidyl esters of polybasic acids, polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyoxyalkylene glycols, and polyglycidyl aromatic polyols. Examples thereof include ethers, hydrogenated compounds of polyglycidyl ethers of aromatic polyols, urethane polyepoxy compounds and epoxidized polybutadienes. These prepolymers can be used alone, or in addition,
It is also possible to use a mixture of two or more thereof.

Other examples of the cationically polymerizable compound contained in the cationically polymerizable composition include the following (1) styrene derivative, (2) vinylnaphthalene derivative and (3).
Examples thereof include vinyl ethers and (4) N-vinyl compounds.

(1) Styrene derivative For example, styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, p-methoxy-β-
Methyl styrene etc.

(2) Vinylnaphthalene derivative For example, 1-vinylnaphthalene, α-methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4
-Methyl-1-vinylnaphthalene, 4-methoxy-1-
Vinyl naphthalene etc.

(3) Vinyl ethers For example, isobutyl vinyl ether, ethyl vinyl ether, phenyl vinyl ether, p-methylphenyl vinyl ether, p-methoxyphenyl vinyl ether,
α-methyl phenyl vinyl ether, β-methyl isobutyl vinyl ether, β-chloroisobutyl vinyl ether and the like.

(4) N-vinyl compounds such as N-vinylcarbazole, N-vinylpyrrolidone, N-vinylindole, N-vinylpyrrole, N-
Vinylphenothiazine, N-vinylacetanilide, N
-Vinylethylacetamide, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, N-vinylimidazole and the like.

The content of the above-mentioned cationically polymerizable compound in the cationically polymerizable composition is preferably 1 to 97% by mass, more preferably 30 to 95% by mass.

Examples of the initiator for the cationically polymerizable photocurable resin include aromatic onium salts. As the aromatic onium salt, a salt of a Group Va element of the periodic table, for example, a phosphonium salt (for example, triphenylphenacylphosphonium hexafluorophosphate), a salt of a Group VIa element, for example, a sulfonium salt (for example, triphenylsulfonium tetrafluoroborate) , Triphenylsulfonium hexafluorophosphate, tris (4-thiomethoxyphenyl) hexafluorophosphate, sulfonium and triphenylsulfonium hexisafluoroantimonate), and salts of Group VIIa elements, such as iodonium salts (eg, diphenyliodonium chloride). Etc.) can be mentioned.

The use of these aromatic onium salts as cationic polymerization initiators in the polymerization of epoxy compounds is described in US Pat. Nos. 4,058,401 and 4,06.
No. 9,055, No. 4,101,513 and No. 4,161,478.

Preferred cationic polymerization initiators include
Examples thereof include sulfonium salts of Group VIa elements. Among them, from the viewpoint of ultraviolet curability and storage stability of the ultraviolet curable composition, triarylsulfonium hexafluoroantimonate is preferable.

39 of Photopolymer Handbook (Photopolymer Forum, published by Industrial Research Society, 1989)
Known photopolymerization initiators described on pages 56 to 56, JP-A-64-1
The compounds described in JP-A No. 3142 and JP-A No. 2-4804 can be optionally used.

<Other Additives> Other additives such as a reaction diluent, a filler, a flow aid, a thixotropic agent, a wetting agent, a defoaming agent and a plasticizer as an additive of the ink composition of the present invention. Can be included. In addition, light resistance agent, ultraviolet absorber,
A stabilizer such as an antioxidant, a polymerization inhibitor or a corrosion inhibitor, or a Si compound, wax or the like may be added.

As the coloring agent in the ink composition of the present invention, conventionally known dyes and pigments can be used. As the coloring agent in the present invention, a pigment is more preferable.

Examples of the water-soluble dye include C.I. I. Direct Black-2, -4, -9, -11, -17,-
19, -22, -32, -80, -151, -154,
-168, -171, -194; C.I. I. Direct Blue-1, -2, -6, -8, -22, -34, -7
0, -71, -76, -78, -86, -112, -1
42, -165, -199, -200, -201, -2
02, -203, -207, -218, -236, -2
87; C.I. I. Direct Red-1, -2, -4,-
8, -9, -11, -13, -15, -20, -28,
-31, -33, -37, -39, -51, -59,-
62, -63, -73, -75, -80, -81, -8
3, -87, -90, -94, -95, -99, -10
1, -110, -189; C.I. I. Direct Yellow-1, -2, -4, -8, -11, -12, -26,-
27, -28, -33, -34, -41, -44, -4
8, -58, -86, -87, -88, -135, -1
42, -144; C.I. I. Food black-1, -2;
C. I. Acid Black-1, -2, -7, -16,
-24, -26, -28, -31, -48, -52,-
63, -107, -112, -118, -119, -1
21, -156, -172, -194, -208;
I. Acid Blue-1, -7, -9, -15, -2
2, -23, -27, -29, -40, -43, -5
5, -59, -62, -78, -80, -81, -8
3, -90, -102, -104, -111, -18
5, -249, -254; C.I. I. Acid Red-
1, -4, -8, -13, -14, -15, -18,-
21, -26, -35, -37, -110, -144,
-180, -249, -257; C.I. I. Acid Yellow-1, -3, -4, -7, -11, -12, -1
3, -14, -18, -19, -23, -25, -3
4, -38, -41, -42, -44, -53, -5
5, -61, -71, -76, -78, -79, -12
2 etc.

The oil-soluble dyes include azo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoimine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, and naphthalene dyes. Phthalimide dye,
Examples include perinone dyes and phthalocyanine dyes,
The present invention is not limited to these.

The water-insoluble dyes and pigments include, but are not limited to, organic pigments, inorganic pigments, colored polymer particles, water-insoluble dyes, disperse dyes and oil-soluble dyes.

As the black pigment, furnace black,
Examples include carbon black pigments such as lamp black, acetylene black, and channel black.
Raven7000, Raven5750, Raven
5250, Raven5000-ULTRAII, Rav
en3500, Raven2000, Raven150
0, Raven1250, Raven1200, Rav
en1190-ULTRAII, Raven1170, R
aven1255, Raven1080, Raven1
060 (above, Colombian Carbon), Reg
al400R, Regal330R, Regal660
R, Mogul-L, Black-Pearls-L,
Monarch700, Monarch800, Mon
arch, 880, Monarch900, Monar
ch1000, Monarch1100, Monarc
h1300, Monarch 1400 (above made by Cabot), Color Black FW1, Color
Black FW2, Color Black FW2
V, Color Black 18, ColorBla
ck FW200, Color Black S15
0, Color Black S160, Color
Black S170, Printex35, Print
xU, Printex Vrintex140U, Pri
ntex140V, Special Black 6,
Special Black 5, Special B
rack 4A, Special Black 4 (above, manufactured by Degussa), No. 25, no. 33, No.
40, No. 47, No. 52, No. 900, No.
2300, MCF-88, MA600, MA7, MA
8, MA100 (above, manufactured by Mitsubishi Chemical Co., Ltd.) and the like can be used. Further, magnetic fine particles such as magnetite and ferrite, titanium black and the like can be used as the black pigment.

Cyan pigments include C.I. I. Pigment Blue-1, C.I. I. Pigment Blue-2,
C. I. Pigment Blue-3, C.I. I. Pigment Blue-15, C.I. I. Pigment Blue-15:
1, C.I. I. Pigment Blue-15: 3, C.I. I.
Pigment Blue-15: 34, C.I. I. Pigment Blue-16, C.I. I. Pigment Blue-22,
C. I. Pigment Blue-60 and the like.

Examples of magenta pigments include C.I. I. Pigment Red-5, C.I. I. Pigment Red-7,
C. I. Pigment Red-12, C.I. I. Pigment Red-48, C.I. I. Pigment Red-4
8: 1, C.I. I. Pigment Red-57, C.I. I.
Pigment Red-112, C.I. I. Pigment Red-122, C.I. I. Pigment Red-123,
C. I. Pigment Red-146, C.I. I. Pigment Red-168, C.I. I. Pigment Red-
184, C.I. I. Pigment Red-202 and the like.

Examples of the yellow pigment include C.I. I. Pigment
Yellow-1, C.I. I. Pigment Yellow-2,
C. I. Pigment Yellow-3, C.I. I. Pigment yellow-12, C.I. I. Pigment Yellow-
13, C.I. I. Pigment Yellow-14, C.I. I.
Pigment yellow-16, C.I. I. Pigment Yellow-17, C.I. I. Pigment Yellow-73,
C. I. Pigment Yellow-74, C.I. I. Pigment Yellow-75, C.I. I. Pigment Yellow-83, C.I. I. Pigment Yellow-93, C.I.
I. Pigment Yellow-95, C.I. I. Pigment Yellow-97, C.I. I. Pigment Yellow-9
8, C.I. I. Pigment Yellow-114, C.I. I.
Pigment Yellow-128, C.I. I. Pigment
Yellow-129, C.I. I. Pigment Yellow-1
51, C.I. I. Pigment Yellow-154 and the like.

In addition to the three primary color pigments of black and cyan, magenta and yellow, specific color pigments such as red, green, blue, brown and white, metallic luster pigments such as gold and silver, colorless extender pigments,
It is also possible to use a plastic pigment or the like.

In addition to the above, a newly synthesized pigment may be used. Further, these pigments may be surface-treated.

Examples of the surface treatment method include treatment with a coupling agent such as alcohol, acid, base and silane compound, polymer grafting treatment and plasma treatment.

The colorant used in the present invention preferably has a small content of organic and inorganic impurities. Generally, commercially available coloring agents have a high content of impurities, so it is desirable to use a purified product thereof. The colorant used in the solid ink composition of the present invention is usually 0.1 to 30% by mass, preferably 0.4 to 10% by mass based on the total mass of the ink.
Used in the range of.

The present invention more preferably uses dispersed pigments. Examples of the dispersant used to disperse the pigment include higher fatty acid salts, alkyl sulfates, alkyl ester sulfates, alkyl sulfonates, sulfosuccinates, naphthalene sulfonates, alkyl phosphates and polyoxys. Alkylene alkyl ether phosphate,
Activator such as polyoxyalkylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, polyoxyethylene fatty acid amide, amine oxide, or styrene, styrene derivative, vinylnaphthalene derivative, acrylic acid, acrylic acid Examples thereof include block copolymers, random copolymers and salts thereof composed of two or more monomers selected from derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid derivatives. be able to.

For dispersing the pigment, various types such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill and a paint shaker can be used. It is also preferable to remove coarse particles from the pigment dispersion using a centrifugal separator or using a filter.

The average particle size of the pigment dispersion used in the ink of the present invention is preferably 200 nm or less, and 50 to 100 nm.
Is more preferable.

The addition amount of the pigment dispersion used in the ink of the present invention is generally preferably in the range of 0.5 to 30% by mass, more preferably 1 to 20%.

If necessary, a water-soluble organic solvent can be added to the ink of the present invention. The water-soluble organic solvent preferably used, for example, alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.), Polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
Butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (eg ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol mono) Ethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether Le, propylene glycol monophenyl ether), amines (e.g., ethanolamine, diethanolamine, triethanolamine, N-
Methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine,
Pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-) Pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-
Examples thereof include imidazolidinone and the like), sulfoxides (for example, dimethyl sulfoxide and the like), sulfones (for example, sulfolane and the like), urea, acetonitrile, acetone and the like.

In addition to the above, the ink of the present invention contains a preservative,
A mildew-proofing agent, a viscosity modifier, etc. may be contained as necessary.

The pH of the ink used in the present invention is 4 to 10.
Is preferred. Furthermore, it is preferably 5 to 9.

Although the reason for the effect of the present invention is not clear, it is presumed that the compatibility between the pigment and the photopolymerizable compound contributes to the dispersion stability of the pigment.

In the ink of the present invention, the surface tension of the ink needs to be in the range of 20 to 60 mN / m, preferably 25 to 50 mN / m, in consideration of the wettability to the recording medium and the head nozzle member. It is set in the range of m. When the surface tension of the ink is less than 25 mN / m, the ink easily overflows from the nozzle, and
When it exceeds 60 mN / m, the drying time becomes long, which is a problem in terms of productivity.

To adjust the surface tension, a surfactant may be contained if necessary. As the surfactant preferably used in the ink of the present invention, for example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates and fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyls. Examples thereof include nonionic surfactants such as ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. Of these, anionic surfactants and nonionic surfactants are particularly preferable.

The ink of the present invention is preferably a liquid having a viscosity at 30 ° C. of 40 to 500 mPa · s. More preferably, it is 50 to 500 mPa · s,
More preferably, it is 100 to 500 mPa · s. 40
If it is less than mPa · s, bleeding is deteriorated and 500 mP
When it exceeds a · s, the smoothness of the image quality is lost.

Next, an example of the ink jet recording apparatus of the present invention will be described with reference to FIG. An ink jet head 1 is mounted on a carriage 2, and the carriage 2 is provided with guide rails 4 and 5 which are installed in parallel to face the platen 3.
It is driven to reciprocate left and right along. A connection line 6 made of a flexible substrate or the like for transmitting a recording signal pulse is provided to the inkjet head 1, and an ink tube 7 for supplying ink from the ink tank 8 to the inkjet head 1.
Are connected. During recording, the sub-scan is performed while the recording medium 9 is successively moved upward along the surface of the platen 3. The recording medium 9 is sent upward by the platen 3,
Ink droplets are ejected from a plurality of nozzles 16 of the ink jet head 1 mounted facing each other in response to an image signal to form an image on the recording medium 9.

Note that, although 1 is an ink jet head, it is not limited to this, and any conventionally known multi-channel ink jet head can be used.

At the time of non-printing such as when the ink jet device is started or in standby, the ink jet head 1 moves away from the position of the platen 3 facing the carriage 2 and moves to the position of the cap 20, and the cap 20 is brought into close contact with the nozzle. It

The present invention further provides an apparatus (means) for irradiating a recording medium, which is printed during or after recording, with ultraviolet rays.
Are provided in FIG. 1 (not shown).

2 to 4 are a plan sectional view, a side sectional view and a schematic view showing an example of the recording unit of the present invention.

[0091]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these embodiments.

Example 1 Preparation of Ink Composition The following ink composition was heated to 50 ° C. and mixed and stirred, and then the obtained liquid was filtered with a filter under heating and cooled to obtain an ink composition. . The solid ink of the comparative sample was prepared by heating to 150 ° C. and mixing. Further, the ultraviolet curable ink of the comparative sample was prepared by mixing without heating.

Solid Ink (Ink 1: Comparison) Coloring agent CI pigment Blue 15: 3 5 parts by mass (average dispersed particle size: 100 nm) Paraffin wax (manufactured by Nippon Seiro Co., Ltd., 155) 45 parts by mass Behenic acid (manufactured by Wako Pure Chemical Industries, Ltd.) ) 30 parts by mass Oleic acid amide (manufactured by Kao, fatty acid amide ON) 20 parts by mass UV curable ink (ink 2: comparison) Colorant CI pigment Blue 15:35 5 parts by mass (average dispersed particle size: 100 nm) Photopolymerizable compound 1,6-Hexanediol diacrylate 15 parts by mass 2-phenoxyethyl acrylate 20 parts by mass Polypropylene glycol diacrylate 20 parts by mass Octyl acrylate 29 parts by mass Polymerization initiator Irgacure 184 (manufactured by Ciba Geigy) 5 parts by mass 2-phenoxyethanol 1 part by mass Part polymerization inhibitor p-Methoxyphenol, hydroquinone The amount added is shown in the table. Ink of the present invention (ink 3) Colorant CI pigment Blue 15: 3 5 parts by mass (average dispersed particle size: 100 nm) Photopolymerizable compound 1,6-hexanediol diacrylate Parts by mass in the table 2-phenoxyethyl acrylate 10 parts by mass Polypropylene glycol diacrylate 10 parts by mass Shin-Nakamura Chemical Co., Ltd. A-9300 Parts by mass in the table Polymerization initiator Irgacure 184 (manufactured by Ciba Geigy) 5 parts by mass 2-phenoxyethanol 1 part by mass Polymerization inhibitor p-methoxyphenol, hydroquinone Addition amount is shown in the table Ink of the present invention (ink 4) Colorant CI pigment Blue 15:35 5 parts by mass (average dispersed particle size: 100 nm) Photopolymerizable compound 1, 6-hexanedioldia Relate Table mass part 2-phenoxyethyl acrylate 10 mass parts Polypropylene glycol diacrylate 10 mass parts AT-600 (manufactured by Kyoeisha Chemical Co., Ltd.) Table mass part Polymerization initiator Irgacure 184 (manufactured by Ciba Geigy) 5 mass parts 2 -Phenoxyethanol 1 part by mass Polymerization inhibitors methoxybenzoquinone, phenothiazine The amount of addition is shown below.

(Inkjet Printer (Inkjet Recording Device)) The inkjet recording device shown in FIG. 1 was used.

(Recording Medium) As the recording medium, a PET sheet having a thickness of 50 μm was used. The PET sheet is at room temperature (2
The temperature was kept at 5 ° C.

These were set in the ink jet printer of FIG. 1 and the output was evaluated. In addition, the ink of the present invention,
The ink temperature is as shown in the table, and the comparison sample solid ink is 1
The comparative sample UV curable ink was printed on the recording medium at 50 ° C. and 25 ° C., respectively.

(UV irradiation) After printing, UV irradiation was performed under the following conditions.

(340-400 nm, 280-400 n
A metal halide type was used for the (ultraviolet light of m wavelength) irradiation lamp, the irradiation energy was 1000 mJ / m ² , and the irradiation timing was 0.5 seconds after printing.

(Output) Images were output using an inkjet printer. The ink temperature during printing was 25 ° C. for the ultraviolet curable ink, 150 ° C. for the solid ink, and 60 ° C. for the ink of the present invention.

(Evaluation of Storage Stability Test) The ink composition was allowed to stand in a constant temperature bath at 60 ° C. for 6 months and then evaluated as follows.

1-1. Dispersion stability test The precipitate and liquid separation were visually evaluated according to the following evaluation criteria.

If no liquid separation or precipitate was confirmed, ◎,
A slight liquid separation can be seen, but the one that returns to the original state by weak shaking is ○, the one in which slight precipitation is confirmed is △, the liquid separation and precipitation is severe, and the one that does not return even if shaken is × ,
The results are shown in the table.

1-2. Physical property change test The viscosity was measured before and after standing and the physical property change was visually evaluated according to the following evaluation criteria. The viscosity was measured at 30 ° C. using a rotational viscometer (EDL model manufactured by Tokimec).

No change in viscosity is indicated by ⊚, viscosity increase by less than 10% relative to the initial value is indicated by ○, viscosity increase by 10 to 50% of the initial value is indicated by △, gel or a solid precipitate is formed. The results are shown in the table.

(Printer Printability Test) The ink composition was used in the ink jet printer of FIG. 1 and the following examinations were conducted.

2-1. Continuous printing (ink ejection stability) test (blurring evaluation) 100 sheets were continuously printed with the inkjet printer of FIG. 1, and the printability was visually evaluated according to the following evaluation criteria.

⊚: No bleeding and good printability, ∘: slightly bleeding and print disorder occurred, Δ: bleeding but character recognition was possible, △: character recognition was impossible due to bleeding The results are shown in the table.

2-2. (Restart (ink clogging property) test) After printing with the inkjet printer of FIG. 1, 4
Printing was performed again with the ink cap left open at 0 ° C. for one day, and the clogging property was visually evaluated on the printed matter according to the following evaluation criteria.

◎, which has good printability without clogging
The results are shown in Table 1, in which a slight omission can be observed, in a case where there is clogging but can be printed by a simple recovery operation, in a case where printing is impossible, and in a case where printing is impossible.

(Image Durability Test) A scratch strength tester HEIDON-18 [manufactured by HEIDON] was used for the solid portion printed by the ink jet printer shown in FIG. 1, and a 0.8 mmR sapphire needle was used as a measuring needle. Measured. The measurement was carried out three times with a 10 cm scratch test at a constant load, and the limit load at which there was no scratched part up to the support was taken as the scratch strength of the present invention, and evaluated according to the following evaluation criteria.

◎: 200 g or more ○: 150 to less than 200 g Δ: 100 to less than 150 g × ... less than 100 g.

(Change in Substrate Temperature) A solid portion (black) was printed by the ink jet printer shown in FIG. 1, and after irradiation with ultraviolet rays, the degree of deformation of the substrate due to heat was visually evaluated according to the following evaluation criteria. did.

⊚: good without any deformation, ◯: slightly observable deformation, ◯: with deformation but no problem in practical use, Δ: with large deformation and unusable level.

(Smoothness) After printing a solid part (black) with the ink jet printer of FIG. 1 and irradiating with ultraviolet rays,
The ink film thickness was measured and the smoothness was visually evaluated.

The thin and good ones are ⊚, the thick ones that are not problematic for high-definition printing are ◯, the lower ones are Δ, and the thicknesses are unusable levels are x.

[0116]

[Table 1]

[0117]

[Table 2]

[0118]

As demonstrated in the examples, the ink jet recording method, the recording unit and the ink jet recording apparatus according to the present invention have ink storage stability, bleed resistance, stability after printing (rubbing resistance, etc.) and smoothness. Stable, high-definition image that improves, suppresses deformation of the recording medium, obtains a good image regardless of the type of recording medium such as paper, plastic film, or metal (especially recording medium that does not absorb ink) Can be printed and has an excellent effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of an example of an inkjet device of the present invention.

FIG. 2 is a plan sectional view showing an example of a recording unit of the present invention.

FIG. 3 is a side sectional view showing an example of a recording unit of the present invention.

FIG. 4 is a schematic diagram of a recording unit showing an example of the present invention.

[Explanation of symbols]

1 inkjet head 14 flow paths 15 Pressure chamber 16 nozzles 17 electrodes 18 Piezoelectric element 19 ink chamber 20 cap 21 Exhaust port 22 Exhaust pipe 23 Exhaust pump P pressure pulse B bubbles

Claims (13)

[Claims] 1. An ink composition containing a photopolymerizable compound, a photopolymerization initiator, and a coloring agent is applied with some ejection energy to eject ink droplets to form an image, and the image is fixed on a recording medium. Then, the inkjet recording method of irradiating ultraviolet rays, wherein the ink composition contains a polymerization inhibitor in an amount of 100 to 10,000 ppm. 2. The ink jet recording method according to claim 1, wherein the colorant is a pigment, and the amount of the pigment added is 0.5 to 30% by mass with respect to the total ink composition. 3. The ink jet recording method according to claim 1, wherein the pigment is a dispersion, and the dispersion has an average dispersed particle diameter of 200 nm or less. 4. The ink jet recording method according to claim 1, wherein the photopolymerization initiator is contained in an amount of 0.1 to 20 mass% with respect to the total ink composition. 5. The viscosity of the ink composition at 30 ° C. is 4
It is 0-500 mPa * s, It is characterized by the above-mentioned.
5. The inkjet recording method according to any one of items 4 to 4. 6. The ink composition is heated at 40 to 150 ° C., and then, by applying some ejection energy, ink droplets are ejected onto a recording medium to form an image.
The inkjet recording method according to any one of claims 1 to 5, wherein an actinic ray is applied after the image is fixed on the recording medium kept at 40 ° C. 7. The total amount of ultraviolet rays irradiated is 10 to 10,000.
The ink jet recording method according to claim 1, wherein the ink jet recording method is mJ / cm ² . 8. The ink jet recording method according to claim 1, wherein the ink droplets formed by the ink jet method are adhered to a recording medium for recording. 9. The ink jet recording method according to claim 1, wherein the ink jet recording method is a recording method utilizing a piezoelectric action of a piezoelectric body. 10. The ink jet recording method according to claim 1, wherein the recording medium has no ink absorbability. 11. A recording unit comprising an ink containing portion containing ink and a head portion for ejecting ink as ink droplets, wherein the inkjet recording method according to claim 9 or 10 is used. unit. 12. The recording unit according to claim 11, wherein the head section discharges ink by a method utilizing a piezoelectric action of a piezoelectric body. 13. An ink jet recording apparatus, wherein the recording unit according to claim 11 or 12 comprises means for irradiating ultraviolet rays.