JP2003105239A - Ink-jet recording method and ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording method and an ink which print an image excellent in character quality and image durability without color mixing on any recording material. SOLUTION: In the method which forms an ink image by ejecting the ink on a recording material from a recording head equipped with plural nozzles capable of selectively controlling the discharge of ink droplets, it is characterized in that the ink does not contain a wax, it is a viscous matter at an ordinary temperature, becomes a liquid state to be ejected by heating to 80 deg.C or more and a surface of the recording material is thermo-controlled at 10-30 deg.C after the ink image is formed on the material until it is completed, the image after forming is cured with at least one process selected from a radiation irradiation and heat. The ink can be used in the method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording method capable of reproducing a high-definition image on any recording material and an ink used in the recording method.

[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. In addition, a hot-melt ink composition that is made of a wax that is solid at room temperature is used to liquefy by heating, etc., to be jetted by applying some energy, and to cool and solidify while adhering to the recording medium to form recording dots. A hot-melt type ink jet recording method 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 at the time of melting can be minimized, clogging of nozzles does not occur. Further, since it solidifies immediately after being adhered, there is no "bleeding", and various recording media such as Japanese paper, drawing paper, and postcards can be used without pretreatment. U.S. Pat. No. 4,3
91,369 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 size of 5 μm or less as a coloring component, or a special ink. Inks using a cationically polymerizable epoxy resin as a binder disclosed in JP-A-58-32674, and water-soluble or water-insoluble dyes as described in JP-A-5-186725 are used. Some of them have been disclosed to facilitate printing on plain paper and recycled paper.

On the other hand, as an image forming method on a plastic substrate, there is known a method using a sublimable dye in an ultraviolet curable resin as described in JP-A-52-142516. Japanese Unexamined Patent Publication No. 9-183927 discloses an ultraviolet curable resin composition coated by an inkjet recording method. JP-A-9-165
Japanese Patent No. 540 discloses an ink which eliminates nozzle clogging with an aqueous ink containing a pigment and an ultraviolet curable resin.

When the above water-based ink is used for printing, it is difficult to print on a recording medium that does not absorb ink, and a large-sized ink drying device is required even when using special paper. Further, due to the problem of bleeding, high-definition printing is difficult and the resolution is limited, so that the application is limited.

High-speed printing is possible with hot melt type ink using wax, but not only the printed dots become thick and the image quality deteriorates, but also the abrasion resistance of the image is very low and the reliability after printing is high. Was hard to get.

The method in which the recording liquid is simply cured with light such as ultraviolet rays has a limited curing speed, and high-definition printing is difficult due to the problem of bleeding and its resolution is limited, so that its application is limited.

Further, when an organic pigment is used as a colorant in an ink composition for ink jet, it has a drawback that it is easily separated in a molten state. As is well known, the sedimentation of particles dispersed in a liquid changes depending on the particle diameter of the particles, the viscosity of the dispersion medium and the sedimentation time, and the higher the viscosity of the dispersion medium, the less likely it is to sediment. On the other hand, when printing with an inkjet printer, the lower viscosity of the ink used is advantageous for high speed and high density and is suitable for high reliability printing, and both have conflicting characteristics. It was

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, particularly in terms of weather resistance, OA
Equipment, general household printers, facsimiles, office printers, indoor / outdoor posters, large signboards, cars,
It is expected to find applications in glass, elevators, wall and building decoration, and even printing on cloth.

[0011]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an ink jet recording method which is very excellent in ink stability, high-speed stable ejection, bleeding resistance, and stability after printing (rubbing resistance, etc.), and any recording method. An object of the present invention is to provide an inkjet recording method capable of stably printing a high-definition image on a material, and further an ink used in the recording method.

[0012]

The above objects of the present invention have been achieved by the following constitutions.

1. In an inkjet recording method for forming an ink image by ejecting ink onto a recording material with a recording head having a plurality of nozzles capable of selectively ejecting ink droplets, the ink does not contain wax and is viscous at room temperature. Yes, the liquid material is discharged by being heated to 80 to 150 ° C., and further, the surface of the recording material is 10 to 30 ° C. before the ink image is formed on the recording material until the end of the ink image formation. An ink jet recording method, wherein the temperature of the image is controlled, and after the image is formed, the image is cured by at least one method selected from radiation irradiation and heat.

2. The ink jet recording method as described in 1 above, wherein the temperature control condition of the surface of the recording material is set based on the recording data for 2.1 pages.

3. 3. The inkjet recording method described in 1 or 2 above, wherein the recording material is a non-absorbent recording material.

4. The contact angle between the ink and the recording material at 25 ° C. is in the range of 20 to 70 degrees.
4. The inkjet recording method according to any one of 3 above.

5. The ink used in the ink jet recording method according to any one of the above 1 to 4 is 0.5 to 50 Pa · s at 25 ° C. and 0.003 to 80 at 150 to 150 ° C.
An ink which is a radiation curable ink having a viscosity of 0.02 Pa · s and containing no wax.

6. 6. The ink according to the above 5, wherein the color material is a pigment. 7. The ink according to 5 or 6 above, which is a radiation curable ink comprising a polyfunctional monomer of 7.30 to 97% by mass and a photopolymerization initiator.

The present invention will be described in more detail. In order to print a high-definition image without bleeding on any recording material, it is desired that the ink viscosity at the time of landing of the ink on the recording material is higher. In particular, when the coloring material is a pigment, it is desired that the ink viscosity be higher in order to obtain an ink having good dispersion stability in which the pigment does not easily settle.

On the other hand, when printing with an ink jet printer, a lower viscosity of the ink ejected from the recording head is advantageous for higher speed and higher density, and is suitable for high speed and high definition printing. ing.

In the ink jet recording method of the present invention, the ink is viscous at room temperature and is ejected from the recording head in a liquid state when heated to 80 ° C. or higher. Furthermore, according to the present invention, the surface of the recording material is kept at a level of 10 before the ink image is formed on the recording material until the end of the ink image formation.
The temperature is controlled to -30 ° C.

The viscosity of the ink is preferably 0.003 to 0.02 Pa · s at 80 ° C. or higher, and if it is out of this range, stable ejection cannot be obtained. The ink viscosity at room temperature of 25 ° C. is preferably 0.5 to 50 Pa · s, and 0.5
When it is lower than Pa · s, the bleeding is deteriorated, and when it is higher than 50 Pa · s, for example, when it is solid, the print dots become thick and the image quality is deteriorated and high-definition printing cannot be performed. Therefore, in the present invention, the conventionally used wax is not included in the ink. When the wax is contained, not only the printed dots become thick and the image quality is inferior, but also there is a problem in the abrasion resistance of the image after printing, and a reliable printed matter cannot be obtained. The viscosity was measured by a rotational viscometer (Tokimec EDL model).

In the present invention, it is important that the high temperature ink is quickly cooled after landing on the recording material. For example, cold air is applied to the recording material in the pre-printing step by the recording head and the printing start portion. There is a method in which a device is provided and the temperature of the recording material surface is adjusted even when high-temperature ink lands.

There is also a method of controlling the temperature of the recording material by adjusting the temperature of a guide which contacts the recording material on the side opposite to the recording head. By uniformly controlling the surface temperature of the recording material to be equal to or lower than a certain level, the image quality is significantly improved, as compared with the case where the recording material is in a room temperature state and the viscosity is increased by natural cooling. This is especially noticeable when the recording material is non-absorbent.

In the present invention, preferably, the temperature control condition of the surface of the recording material is set based on the recording data for one page. By this, without being affected by the recording duty,
High quality images can be obtained stably.

Examples of the composition of the ink used in the ink jet recording method of the present invention include the following photopolymerizable compounds and photopolymerization initiators.

The photopolymerizable compound is a radically polymerizable compound, for example, JP-A-7-159983 and JP-B-7-
No. 31399, JP-A-8-224982, JP-A-10
No. 863, JP-A-9-134011 and other publications, and JP-A-9-134011, a photocurable material using a photopolymerizable composition. Also,
Cationic polymerization type photocurable resins are known, and recently, cationic polymerization type photocurable resins sensitized in the long wavelength region of visible light or longer are also disclosed, for example, in JP-A-6-43633 and JP-A-8-33. It is disclosed in Japanese Patent Publication No.-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 a chemical form of monomer, oligomer and polymer are included.

The radical-polymerizable compound may be used alone, or two or more kinds may be used in combination at an arbitrary ratio in order to improve the desired 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, dipentaerythritol tetraacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate, acrylic acid derivatives such as N-methylol acrylamide, diacetone acrylamide, epoxy acrylate, methyl methacrylate, n- Butylme Acrylate, 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, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxy) Methacryl derivatives such as polyethoxyphenyl) propane, other, allyl glycidyl ether, diallyl phthalate, derivatives of allyl compounds such as triallyl trimellitate, more specifically, Shinzo Yamashita, "Crosslinking agent handbook", (1981 Taiseisha); Kiyomi Kato, "UV / EB curing handbook (raw materials)" (1985, Kobunshi Kogyokai); Radtech Research Group, "UV / EB" Application of technology and the market ", 79
Page, (1989, CMC); Eiichiro Takiyama,
Commercially available products described in "Polyester Resin Handbook" (1988, Nikkan Kogyo Shimbun) and the like, or radically polymerizable or crosslinkable monomers, oligomers and polymers known in the art can be used.

As a radical polymerization initiator, Japanese Patent Publication No.
-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 the like, 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.)", No. 30
Vol., Page 174 (1986), metal allene complexes, JP-A-5-213861 and JP-A 5-2.
(Oxo) sulfonium organoboron complex described in JP-A-55347, titanocene described in JP-A-61-151197, and "Coordination Chemistry Review".
ry Review) ", Vol. 84, No. 85-277.
Page (1988) and transition metal complexes containing a transition metal such as ruthenium described in JP-A-2-182701, 2,4,5 in JP-A-3-209477.
-Triarylimidazole dimer, carbon tetrabromide, organic halogen compounds described in JP-A-59-107344, and the like. These polymerization initiators are preferably contained in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the compound having a radically polymerizable ethylenic unsaturated bond.

As the cationic polymerization type photocurable resin, an epoxy type UV curable prepolymer of a type (mainly an epoxy type) in which polymerization occurs 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 cationically polymerizable compounds contained in the cationically polymerizable composition include, for example, the following (1) styrene derivatives, (2) vinylnaphthalene derivatives, 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-.
Methylstyrene etc. (2) Vinylnaphthalene derivative, for example, 1-vinylnaphthalene, α-methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4
-Methyl-1-vinylnaphthalene, 4-methoxy-1-
(3) Vinyl ethers such as vinyl naphthalene, for example, isobutyl vinyl ether, ethyl vinyl ether, phenyl vinyl ether, p-methylphenyl vinyl ether, p-methoxyphenyl vinyl ether,
α-Methylphenyl vinyl ether, β-methyl isobutyl vinyl ether, β-chloroisobutyl vinyl ether, etc. (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.

Examples of the initiator for the cationic polymerization type 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 hexafluoroantimonate), and salts of Group VIIa elements such as iodonium salts (eg, diphenyliodonium chloride) ) Can be mentioned.

The use of such an aromatic onium salt as a cationic polymerization initiator in the polymerization of epoxy compounds is described in US Pat. Nos. 4,058,401 and 4,0.
69,055, 4,101,513 and 4,161,478.

The preferred cationic polymerization initiator is
Examples thereof include sulfonium salts of Group VIa elements. Of these, triarylsulfonium hexafluoroantimonate is preferable from the viewpoint of the ultraviolet curability and the storage stability of the ultraviolet curable composition. Further, known photopolymerization initiators described on pages 39-56 of Photopolymer Handbook (published by Industrial Research Society, published by Photopolymer Society, 1989) are described in JP-A-64-13142 and JP-A-2-4804. It is possible to use any of these compounds.

The amount of the photopolymerizable compound added to the ink of the present invention is preferably 30 to 97% by mass, more preferably 50 to 95% by mass.

From the viewpoint of safety such as odor and skin irritation, the ink is more preferably composed of 30 to 97% by mass of a polyfunctional monomer.

Further, in the present invention, it is necessary to select the photopolymerizable compound so that it is a viscous substance at room temperature and becomes a liquid state by heating at 80 ° C. or higher.

In the present invention, a pigment having excellent weather resistance is preferable as the coloring material, but any known coloring material such as a soluble dye and an oil dye can be used.

The pigment preferably used in the present invention will be described. The color developability (color density per added concentration) is not always high, and in addition, since it is difficult to produce a uniform fine particle dispersion, there is a phenomenon in which the melt viscosity increases excessively when the concentration is high. Those that have not been put to practical use can be used. Although not particularly limited, for example, the following organic or inorganic pigments described in the color index can be used in the present invention.

As the red or magenta pigment, Pig
ment Red 3, 5, 19, 22, 31, 38,
43, 48: 1, 48: 2, 48: 3, 48: 4, 4
8: 5, 49: 1, 53: 1, 57: 1, 57: 2, 5
8: 4, 63: 1, 81, 81: 1, 81: 2, 81:
3, 81: 4, 88, 104, 108, 112, 12
2, 123, 144, 146, 149, 166, 16
8, 169, 170, 177, 178, 179, 18
4, 185, 208, 216, 226, 257, Pig
ment Violet 3, 19, 23, 29, 3
0, 37, 50, 88, Pigment Orange
13, 16, 20, 36, as blue or cyan pigments, Pigment Blue 1, 15, 15: 1,
15: 2, 15: 3, 15: 4, 15: 6, 16, 17
-1, 22, 27, 28, 29, 36, 60, and as the green pigment, Pigment Green 7, 26, 3
6, 50, as a yellow pigment, Pigment Yell
ow 1, 3, 12, 13, 14, 17, 34, 35,
37, 55, 74, 81, 83, 93, 94, 95, 9
7, 108, 109, 110, 137, 138, 13
9,153,154,155,157,166,16
7, 168, 180, 185, 193, and as the black pigment, Pigment Black 7, 28, 26 or the like can be used according to the purpose.

Specific product names are, for example, Chromo Fine Yellow 2080, 5900, 5930, AF.
-1300, 2700L, Chromo Fine Orange 37
00L, 6730, Chromo Fine Scarlet 675
0, Chromo Fine Magenta 6880, 6886, 68
91N, 6790, 6887, Chromo Fine Violet RE, Chromo Fine Red 6820, 683
0, Chromo Fine Blue HS-3, 5187, 510
8, 5197, 5085N, SR-5020, 502
6, 5050, 4920, 4927, 4937, 482
4, 4933GN-EP, 4940, 4973, 520
5, 5208, 5214, 5221, 5000P, Chromo Fine Green 2GN, 2GO, 2G-550D,
5310, 5370, 6830, Chromo Fine Black A-1103, Seika Fast Yellow 10GH, A-
3, 2035, 2054, 2200, 2270, 230
0, 2400 (B), 2500, 2600, ZAY-2
60, 2700 (B), 2770, Seika Fast Red 8040, C405 (F), CA120, LR-11.
6, 1531B, 8060R, 1547, ZAW-26
2, 1537B, GY, 4R-4016, 3820, 3
891, ZA-215, Seika Fast Carmine 6B1
476T-7, 1483LT, 3840, 3870, Seika Fast Bordeaux 10B-430, Seika Light Rose R40, Seika Light Violet B800, 78
05, Seika Fast Maroon 460N, Seica Fast Orange 900, 2900, Seica Light Blue C7
18, A612, cyanine blue 4933M, 4933
GN-EP, 4940, 4973 (manufactured by Dainichi Seika Kogyo),
KET Yellow 401, 402, 403, 40
4, 405, 406, 416, 424, KET Ora
nge 501, KET Red 301, 302, 3
03, 304, 305, 306, 307, 308, 30
9, 310, 336, 337, 338, 346, KET
Blue 101, 102, 103, 104, 10
5, 106, 111, 118, 124, KET Gre
en 201 (Dainippon Ink and Chemicals), Colorte
x Yellow 301, 314, 315, 316,
P-624, 314, U10GN, U3GN, UNNN,
UA-414, U263, Finecol Yellow
w T-13, T-05, Pigment Yellow
w1705, Colortex Orange 20
2, Colortex Red 101, 103, 11
5, 116, D3B, P-625, 102, H-102
4, 105C, UFN, UCN, UBN, U3BN, U
RN, UGN, UG276, U456, U457, 10
5C, USN, Colortex Maroon60
1, Colortex Brown B610N, Col
ortex Violet 600, Pigment R
ed 122, Colortex Blue 516, 5
17, 518, 519, A818, P-908, 51
0, Colortex Green 402, 403, C
colortexBlack 702, U905 (manufactured by Sanyo Pigment), Lionol Yellow 1405G, Li
onol Blue FG7330, FG7350, F
G7400G, FG7405G, ES, ESP-S (manufactured by Toyo Ink), Toner Magenta E02,
Permanent Rubin F6B, Toner
Yellow HG, Permanent Yellow
w GG-02, Hostapeam BlueB2G
(Manufactured by Hoechst Industry), carbon black # 26
00, # 2400, # 2350, # 2200, # 100
0, # 990, # 980, # 970, # 960, # 95
0, # 850, MCF88, # 750, # 650, MA
600, MA7, MA8, MA11, MA100, MA
100R, MA77, # 52, # 50, # 47, # 4
5, # 45L, # 40, # 33, # 32, # 30, # 2
5, # 20, # 10, # 5, # 44, CF9 (manufactured by Mitsubishi Chemical) and the like.

It is also possible to use a dispersion liquid in which the pigment is dispersed in water or a solvent in a high concentration in advance. For example, MICRO
PIGMO WMBK-5, WMBE-5, WMRD-
5, WMYW-5, AMBK-2, AMYW-2, AM
BE-4 (manufactured by Orient Chemical Co., Ltd.) and the like can be mentioned.

The appropriate amount of the pigment added is 0.1 to 20 parts by mass. If the amount is less than 0.1 parts by mass, the image quality will deteriorate,
If the amount is more than the amount by mass, the ink viscosity characteristics are adversely affected. Further, two or more kinds of color materials can be mixed and used at appropriate times for color adjustment or the like.

In order to further develop the functionality of the ink composition of the present invention, various sensitizers, light stabilizers, surface treatment agents, surfactants, viscosity reducing agents, antioxidants, antiaging agents, crosslinkers. Accelerators, polymerization inhibitors, plasticizers, preservatives, pH adjusters, defoamers, humectants, dispersants and the like can be mixed.

In the present invention, 25 inks and recording materials are used.
The contact angle at 0 ° C. is preferably in the range of 20 to 70 degrees.

If it is less than 20 degrees, the wettability of the ink is too good, and bleeding becomes a problem, and if it exceeds 70 degrees, the part where the ink is not wet becomes visible as streaks and the quality is poor. Especially, it becomes remarkable in the non-absorbent material.

As a method of adjusting the contact angle, it is possible to adjust the amount of the surfactant in the ink and / or the surface of the recording material by corona discharge treatment, etc., as already known.

An automatic contact angle measuring device CA-Z type manufactured by Kyowa Interface Science Co., Ltd. was used for measuring the contact angle. In the present invention, after the image is formed on the recording material, the image is rapidly cured.
Examples of the curing means include an ultraviolet (UV) irradiation lamp, an electron beam, heat and the like. Since heat may be generated in the UV irradiation lamp and the recording medium may be deformed, it is desirable to provide a cooling mechanism such as a cold mirror, a cold filter, and work cooling. Types of lamps include high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halides, and the like. The ultra-high pressure mercury lamp is a point light source,
DeepU with high light utilization efficiency in combination with optical system
The V type is capable of irradiation in the short wavelength region. The metal halide has a wide wavelength range and is effective for coloring.
Halides of metals such as Pb, Sn and Fe are used and can be selected according to the absorption spectrum of the photoinitiator.
Any lamp that is effective for curing can be used without particular limitation.

There are many books on UV curing technology, such as "UV / EV Curing Technology" Comprehensive Technology Center (1982) edited by Minoru Imoto. By this curing, the image durability is significantly improved and the reliability after printing is secured.

[0053]

Example 1 Ink composition The ink composition of the present invention shown in Table 1 was heated to 80 ° C., mixed and stirred, filtered through a filter in a heated state, and cooled to obtain a viscous ink composition. Got

As comparative ink A, a solid ink was prepared by heating at 150 ° C. and mixing. Further, as a comparative ink B, a liquid ultraviolet curable ink was prepared by mixing without heating.

[0055]

[Table 1]

The ink viscosity was measured by measuring the melt viscosity at 25 ° C. and 80 ° C. using a rotational viscometer (EDL model manufactured by Tokimec).

As an ink jet printer, a large format ink jet printer "IGUAZU 1044SD" manufactured by Konica Corp. was improved, a device for blowing cooling air on the surface of the recording material, a sensor for detecting the temperature of the surface of the recording material, The temperature of the ink supply line to the recording head was adjusted (80 ° C. setting).

Recording materials listed in Table 2 (OPP, OPS, P
An image was formed on ET, aluminum, plain paper, PVC) using the above ink under the conditions shown in Table 2.

The contact angle at 25 ° C. was measured by an automatic contact angle measuring device CA-Z type manufactured by Kyowa Interface Science Co., Ltd.

After printing out, ultraviolet rays were irradiated under the following conditions. The irradiation lamp used was a metal halide lamp manufactured by Nippon Battery Co., Ltd. 120 W / cm, and ultraviolet irradiation was performed at an ultraviolet irradiation amount of 1000 mJ / cm ² at 365 nm.

The obtained samples were evaluated by the following methods, and the results are shown in Table 2. [Character quality] Using each color ink of Y, M, C, and K, print 6-point MS Mincho typeface characters at the target density, magnify the rubbing of the characters with a magnifying glass, and evaluate the character quality according to the following criteria. I went.

◎ ・ ・ ・ No rustling ○ ・ ・ ・ Slightly rustling is visible △ ・ ・ ・ Rattle is visible, but it can be discerned as characters and is at the level where it can be used as close as possible × ... Level [color mixture (bleeding)] Y, M, C, K at 720 dpi
1 dot for each color is printed so as to be adjacent to each other, and each adjacent color d
ot was magnified with a magnifying glass, the degree of bleeding was visually observed, and color mixing was evaluated according to the following criteria. In addition, dpi represents the number of dots per 2.54 cm.

∘: Adjacent dot shapes maintain a perfect circle without blurring ○: Adjacent dot shapes maintain a nearly perfect circle with almost no bleeding Δ: Adjacent dots slightly blur However, the dot shape is slightly distorted, but it is at a level where it can be used at the last minute × ... Adjacent dots are blurred and mixed together, and they cannot be used [Image durability] Transfer layers after solid image formation for each color are transferred to Tokubishi Art Scratch strength tester HEIDON-18
[HEIDON] was used, and the measuring needle was a 0.8 mmR sapphire needle. Measurement is a constant load 10
The scratch test of cm was carried out three times, and the limit load at which there was no scratched portion up to the support was taken as the scratch strength of the present invention, and judged according to the following criteria.

[0064] ○: 200g or more △: 100 g or more and less than 200 g × ... less than 100 g

[0065]

[Table 2]

It can be seen from Table 2 that the samples of the present invention are printed on all recording materials with images having excellent character quality, no color mixing, and excellent image durability.

[0067]

EFFECT OF THE INVENTION Ink jet recording method which is very excellent in ink stability, high-speed stable ejection, bleeding resistance, and stability after printing (rubbing resistance, etc.), and stable and high-definition images can be obtained on any recording material. Inkjet recording method that can print
Furthermore, the ink used in the above recording method could be provided.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B41J 3/04 101Y F term (reference) 2C056 EA05 EA13 EC13 EC29 FC02 FD01 FD07 FD20 HA44 2H086 BA01 BA02 BA05 BA15 BA41 BA54 BA59 BA61 BA62 4J039 AD21 AE04 AE05 AE06 AE07 AE08 BE01 BE06 BE07 BE27 EA03 EA04 EA36 EA44 EA47 EA48 GA24

Claims (7)

[Claims] 1. An ink jet recording method for forming an ink image by ejecting ink onto a recording material with a recording head having a plurality of nozzles capable of selectively ejecting ink droplets, wherein the ink does not contain wax and is at room temperature. Is a viscous substance, and when it is heated to 80 to 150 ° C., it becomes a liquid state and is ejected. Further, before the ink image is formed on the recording material until the end of the ink image formation, the surface of the recording material is Is a temperature controlled to 10 to 30 ° C., and the image is cured by at least one method selected from radiation irradiation and heat after image formation. 2. The ink jet recording method according to claim 1, wherein the temperature control condition of the surface of the recording material is set based on the recording data for one page. 3. The ink jet recording method according to claim 1, wherein the recording material is a non-absorbent recording material. 4. The contact angle between the ink and the recording material at 25 ° C. is in the range of 20 to 70 degrees.
4. The inkjet recording method according to any one of 3 above. 5. The ink used in the ink jet recording method according to claim 1, wherein the ink is 0.5 to 50 Pa · s at 25 ° C. and 0.003 to 80 at 150 to 150 ° C.
An ink which is a radiation curable ink having a viscosity of 0.02 Pa · s and containing no wax. 6. The ink according to claim 5, wherein the color material is a pigment. 7. The ink according to claim 5, which is a radiation-curable ink comprising 30 to 97% by mass of a polyfunctional monomer and a photopolymerization initiator.