JP2003326825A - Imaging method, printed matter, and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging method using an ink jet recording process applicable to all kinds of recording materials, with a recorded high definition image showing a high character quality and without the generation of a color mixture and creases and curling in printed matter, and also to provide a printed matter and a recording device. <P>SOLUTION: The imaging method discharges an active ray-curable ink onto a recording material by a recording head with at least a single nozzle capable of selectively controlling ink droplets. The ink contains a photooxidation generating agent and is cured with the help of an active ray having a maximum illuminance in the wavelength range of 280 to 320 nm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, a printed matter and a recording apparatus by an ink jet recording method capable of stably reproducing a high definition image on any recording material without shrinkage of the recording material.

[0002]

2. Description of the Related Art In recent years, the inkjet recording method has been simple and easy.
Since it is possible to create images at low cost, it has been applied to various printing fields such as photography, various printing, marking, and special printing such as color filters. In particular, a recording device that emits and controls fine dots, and ink and ink absorption with improved color reproduction range, durability, emission suitability, coloring of color materials, and surface gloss have been dramatically improved. Using special paper,
It is also possible to obtain image quality comparable to silver salt photography. The improvement in image quality of today's inkjet recording system is achieved only when all of the recording device, ink, and special paper are provided.

However, the ink jet system requiring special paper has problems that the recording medium is limited and the cost of the recording medium is increased. Therefore, many attempts have been made to record on a transfer medium different from dedicated paper by an inkjet method. Specifically, a phase change inkjet method using a solid wax ink at room temperature, a solvent inkjet method using an ink mainly composed of a quick-drying organic solvent, and a UV inkjet method in which cross-linking is performed by ultraviolet (UV) light after recording. Is.

Among them, the UV ink jet system has been attracting attention in recent years because it has a relatively low odor as compared with the solvent type ink jet system and can perform recording on a recording medium having a fast drying property and no ink absorbing property. Fair 5-
54667, JP-A-6-200204, Special Table 200
No. 0-504778, a UV curable inkjet ink is disclosed.

However, even if these inks are used, the dot diameter after landing changes greatly depending on the type of recording material and the working environment, and a high-definition image is formed on all recording materials. Is impossible.

Further, the ink used in the conventional UV ink jet system has a problem that the recording material tends to shrink. In particular, in thin film plastic films used in soft packaging such as food packaging and adhesive labels, shrinkage is particularly likely to occur, and as a result, the UV inkjet method has not yet been put to practical use in soft packaging printing and label printing. is the current situation.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide excellent character quality for all recording materials without causing color mixing.
An object of the present invention is to provide an image forming method, a printed matter, and a recording apparatus by an inkjet recording method capable of recording a high-definition image and without causing wrinkles and curls of the printed matter.

[0008]

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

1. In an image forming method of ejecting an ink cured by an actinic ray onto a recording material in a recording head having at least one nozzle capable of selectively ejecting an ink droplet, the ink contains a photo-acid generator, An image forming method, characterized in that the ink is cured by using an actinic ray having a maximum illuminance in a wavelength region of 280 to 320 nm.

2. 2. The image forming method as described in 1 above, wherein the photo-acid generator is at least one sulfonium compound.

3. 3. The image forming method as described in 1 or 2 above, wherein the ink contains at least one oxetane compound as a photopolymerizable compound.

4. Any one of the items 1 to 3, wherein at least one color of the ink is white ink.
The image forming method according to item.

5. 0.001 after the ink has landed
The method for forming an image according to any one of items 1 to 4, wherein the actinic ray is irradiated for about 2.0 seconds.

6. Item 6. The image forming method described in any one of Items 1 to 5, wherein the total ink film thickness after the ink has landed and irradiated with actinic rays to be cured is 2 to 20 µm.

7. 7. The image forming method according to any one of items 1 to 6, wherein the amount of ink droplets ejected from each nozzle of the recording head is 2 to 15 pl.

8. Using a non-absorbent recording material,
A printed matter produced by the image forming method according to any one of items 7.

9. The printed matter according to item 8, wherein the surface energy of the non-absorbent recording material is 35 to 60 dyn / cm.

10. A recording apparatus used in the image forming method according to any one of items 1 to 7.

11. A recording apparatus, which is used for producing the printed matter according to the item 8 or 9.

12. 10. The total power consumption of the light source for irradiating the actinic ray is less than 1 kW · hr.
Alternatively, the recording device according to item 11.

The present invention will be described in detail below. In the image forming method of the present invention, the ink composition is ejected onto a recording material by an inkjet recording method to draw an image, and then the ink is cured by irradiating with actinic rays such as ultraviolet rays.

The image forming method of the present invention is characterized in that the ink contains a photo-acid generator and is cured with an actinic ray having a maximum illuminance in the wavelength region of 280 to 320 nm. The configuration according to the present invention is particularly effective when ejecting a large amount of white ink. The inventor
By curing the ink with an actinic ray having the highest illuminance in the wavelength range of 80 to 320 nm, the thickness of the printed ink film becomes thicker than in ordinary printing. It has been newly found that the curl and wrinkle of the recording material can be remarkably reduced. In the conventional actinic ray curable ink jet recording, a high pressure mercury lamp or a metal halide lamp has been used for curing the ink. However, since these rays have large illuminance wavelength peaks near 365 nm and 254 nm, conventionally, soft packaging printing is performed. In the field of label printing and label printing, from the viewpoint of wrinkles and curls of recording materials, actinic radiation-curable inkjet recording has not been put to practical use, but by adopting the constitution of the present invention, it is possible to use it in those fields as well. It is fully effective.

Next, the photoacid generator that can be used in the present invention will be described. As the photoacid generator, for example, a chemically amplified photoresist or a compound used for photocationic polymerization is used (Organic Electronic Materials Research Group, "Organic Materials for Imaging", Bushin Publishing (1993), 187). (See page 192). Examples of compounds suitable for the present invention are given below.

[0024] First, diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium _{B (C 6 F 5) 4} -, PF 6 -, AsF 6 -,
Mention may be made of SbF ₆ ⁻ and CF ₃ SO ₃ ⁻ salts.

Specific examples of onium compounds that can be used in the present invention are shown below.

[0026]

[Chemical 1]

Secondly, a sulfonated compound which generates a sulfonic acid can be mentioned, and its specific compound is exemplified below.

[0028]

[Chemical 2]

Thirdly, a halide which photo-generates a hydrogen halide can also be used, and its specific compound is exemplified below.

[0030]

[Chemical 3]

Fourthly, an iron allene complex can be mentioned.

[0032]

[Chemical 4]

The ink according to the present invention is disclosed in JP-A-8-248.
No. 561 and JP-A No. 9-34106, it is preferable to contain an acid proliferating agent that newly generates an acid by an already-known acid generated by irradiation with actinic rays. By using the acid multiplying agent, it is possible to further improve the ejection stability.

The ink according to the present invention preferably contains at least one sulfonium compound as a photoacid generator among the above compounds. At least 1
By using one kind of sulfonium compound, there is an effect that the problem of wrinkles at the time of ink curing is further reduced and the ejection stability is improved.

Next, the photopolymerizable compound used in the present invention will be described. As the cationic photopolymerizable monomer, various known cationically polymerizable monomers can be used. For example, JP-A-6-9714 and JP-A-2001-31
892, JP 2001-40068, JP 2001-5
5507, JP 2001-310938 A, JP 2001 A
-310937, the epoxy compound, the vinyl ether compound, the oxetane compound etc. which were illustrated by Unexamined-Japanese-Patent No. 2001-220526 are mentioned.

Preferred aromatic epoxides are:
A di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or its alkylene oxide adduct with epichlorohydrin, for example, bisphenol A or its di- or polyglycidyl ether of an alkylene oxide adduct. , Di- or polyglycidyl ether of hydrogenated bisphenol A or its alkylene oxide adduct, and novolac type epoxy resin. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

At least one alicyclic epoxide is used.
A cyclohexene oxide- or cyclopentene oxide-containing compound obtained by epoxidizing a compound having a cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid is preferable. .

Preferred aliphatic epoxides are aliphatic polyhydric alcohols or di- or polyglycidyl ethers of their alkylene oxide adducts. Typical examples thereof are diglycidyl ether of ethylene glycol and diglycidyl propylene glycol. Diglycidyl ether of alkylene glycol such as glycidyl ether or diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, polyethylene glycol or its alkylene Polyalkylene such as diglycidyl ether of oxide adduct, polypropylene glycol or diglycidyl ether of alkylene oxide adduct thereof Diglycidyl ethers of recall and the like. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

Among these epoxides, in consideration of the rapid curing property, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable. In the present invention, one of the above epoxides may be used alone,
You may use it in combination of 2 or more types as appropriate.

As the vinyl ether compound, for example,
Diethylene glycol such as ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane trivinyl ether. Or trivinyl ether compound, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-
Examples thereof include monovinyl ether compounds such as ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl ether-O-propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether and octadecyl vinyl ether.

Of these vinyl ether compounds, di- or trivinyl ether compounds are preferable, and divinyl ether compounds are particularly preferable, in consideration of curability, adhesion and surface hardness. In the present invention, one of the above vinyl ether compounds may be used alone, or two or more thereof may be used in an appropriate combination.

In the present invention, it is preferable to contain at least one oxetane compound as the photopolymerizable compound for the purpose of suppressing the shrinkage of the recording material when the ink is cured.

The oxetane compound according to the present invention is a compound having an oxetane ring, and is disclosed in JP-A-2001-2.
Any known oxetane compound such as those introduced in 20526 and JP 2001-310937 A can be used.

In the oxetane compound according to the present invention,
When a compound having 5 or more oxetane rings is used, the viscosity of the ink composition becomes high, which makes it difficult to handle, and the glass transition temperature of the ink composition becomes high. It will not be enough. The compound having an oxetane ring used in the present invention is
A compound having 1 to 4 oxetane rings is preferable.

Specific examples of the compound having an oxetane ring according to the present invention will be described below, but the present invention is not limited thereto.

An example of the compound having one oxetane ring is a compound represented by the following general formula (1).

[0047]

[Chemical 5]

In the general formula (1), R ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, and an allyl group. , An aryl group, a furyl group or a thienyl group. R ² is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, a 2-methyl- group. 2-propenyl group, 1-butenyl group,
2-butenyl group, alkenyl group having 2 to 6 carbon atoms such as 3-butenyl group, phenyl group, benzyl group, fluorobenzyl group, methoxybenzyl group, group having aromatic ring such as phenoxyethyl group, ethylcarbonyl group, Propylcarbonyl group, butylcarbonyl group, etc., C2-C6 alkylcarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, etc., C2-C6
6 alkoxycarbonyl groups, or N-C2-C6 groups such as ethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group and pentylcarbamoyl group
And an alkylcarbamoyl group. As the oxetane compound used in the present invention, it is particularly preferable to use a compound having one oxetane ring because the resulting composition has excellent tackiness, low viscosity and excellent workability.

Examples of compounds having two oxetane rings include compounds represented by the following general formula (2).

[0050]

[Chemical 6]

In the general formula (2), R ¹ is the same group as that in the general formula (1). R ³ is, for example, a linear or branched alkylene group such as ethylene group, propylene group, butylene group, poly (ethyleneoxy) group,
Linear or branched unsaturated hydrocarbon group such as poly (propyleneoxy) group or linear or branched poly (alkyleneoxy) group, propenylene group, methylpropenylene group, butenylene group, or carbonyl group or carbonyl group An alkylene group containing a group, an alkylene group containing a carboxyl group, an alkylene group containing a carbamoyl group, and the like.

Further, as R ³ , the following general formula (3),
A polyvalent group selected from the groups represented by (4) and (5) can also be mentioned.

[0053]

[Chemical 7]

In the general formula (3), R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, a methoxy group, an ethoxy group, a propoxy group and a butoxy group. It is an alkoxy group having 1 to 4 carbon atoms such as a group, a halogen atom such as a chlorine atom and a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkoxycarbonyl group, a carboxyl group, or a carbamoyl group.

[0055]

[Chemical 8]

In the general formula (4), R ⁵ is an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C
It represents (CF ₃ ) ₂ or C (CH ₃ ) ₂ .

[0057]

[Chemical 9]

In the general formula (5), R ⁶ has 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group and butyl group.
Is an alkyl group or an aryl group. n is 0 to 2
It is an integer of 000. R ⁷ is a methyl group, an ethyl group, a propyl group, a butyl group, an alkyl group having 1 to 4 carbon atoms, or an aryl group. Examples of R ^{7 also} include a group selected from the groups represented by the following general formula (6).

[0059]

[Chemical 10]

In the general formula (6), R ⁸ is a methyl group, an ethyl group, a propyl group, a butyl group or the like having 1 to 4 carbon atoms.
Is an alkyl group or an aryl group. m is 0 to 1
00 is an integer.

The following compounds may be mentioned as specific examples of the compound having two oxetane rings.

[0062]

[Chemical 11]

Exemplified compound 1 is a compound in which R ¹ is an ethyl group and R ³ is a carboxyl group in the general formula (2). Further, Exemplified Compound 2 is a compound in which, in the general formula (2), R ¹ is an ethyl group, R ³ is the general formula (5), R ⁶ and R ⁷ are methyl groups, and n is 1.

Among the compounds having two oxetane rings, preferred examples other than the above compounds include compounds represented by the following general formula (7). In general formula (7), R ¹ has the same meaning as R ¹ in the general formula (1).

[0065]

[Chemical 12]

As an example of the compound having 3 to 4 oxetane rings, a compound represented by the following general formula (8) can be given.

[0067]

[Chemical 13]

[0068] In the general formula (8), R ¹ is the same meaning as R ¹ in the general formula (1). R ⁹ is, for example, a branched alkylene group having 1 to 12 carbon atoms such as the groups represented by the following A to C, a branched poly (alkyleneoxy) group such as the group represented by the following D, or the following E. Examples thereof include branched polysiloxy groups such as the groups shown. j is 3 or 4.

[0069]

[Chemical 14]

In the above A, R ¹⁰ is a lower alkyl group such as methyl group, ethyl group or propyl group. Moreover, in said D, p is an integer of 1-10.

Exemplified Compound 3 is mentioned as an example of the compound having 3 to 4 oxetane rings.

[0072]

[Chemical 15]

Further, examples of compounds having 1 to 4 oxetane rings other than those described above include compounds represented by the following general formula (9).

[0074]

[Chemical 16]

[0075] In the general formula (9), R ⁸ has the same meaning as R ⁸ in the general formula (6). R ¹¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or a trialkylsilyl group, and r is 1 to 4.

The following compounds are preferred specific examples of the oxetane compound used in the present invention.

[0077]

[Chemical 17]

The method for producing each of the above-mentioned compounds having an oxetane ring is not particularly limited and may be according to a conventionally known method. For example, Pattison (DB Pattiso)
n, J. Am. Chem. Soc. , 3455, 79
(1957)) disclosed is a method for synthesizing an oxetane ring from a diol. In addition to these, compounds having 1 to 4 oxetane rings having a high molecular weight of about 1000 to 5000 are also included. The following compounds are mentioned as an example of these concrete compounds.

[0079]

[Chemical 18]

When coloring the ink composition according to the present invention, a coloring material is added. As the colorant, various colorants that can be dissolved or dispersed in the main component of the polymerizable compound can be used, but a pigment is preferable from the viewpoint of weather resistance.

The pigments that can be preferably used in the present invention are listed below. C. I Pigment Yellow-1, 3, 1
2, 13, 14, 17, 81, 83, 87, 95, 10
9, 42, C.I. I Pigment Orange-16, 36,
38, C.I. I Pigment Red-5, 22, 38, 4
8: 1, 48: 2, 48: 4, 49: 1, 53: 1, 5
7: 1, 63: 1, 144, 146, 185, 101, C.I. I Pigment Violet-19, 23, C.I. I Pigment Blue-15: 1, 15:
3, 15: 4, 18, 60, 27, 29, C.I. I Pigment Green-7, 36, C.I. I Pigment White-6, 18, 2
1, C.I. I Pigment Black-7, and in the present invention, it is preferable to use a white ink in order to improve the color hiding property on a transparent substrate such as a plastic film. In particular, in soft packaging printing and label printing, it is preferable to use a white ink, but since the ejection amount is large, from the viewpoints of the ejection stability described above and the occurrence of curling and wrinkling of the recording material, the amount used is naturally There is a limit.

For the dispersion of the above pigment, for example, 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, a paint shaker or the like can be used. Further, it is possible to add a dispersant when the pigment is dispersed. It is preferable to use a polymer dispersant as the dispersant, and examples of the polymer dispersant include Solsperse series manufactured by Avecia. It is also possible to use synergists corresponding to various pigments as the dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. A solvent or a polymerizable compound is used as the dispersion medium, but the irradiation ray-curable ink used in the present invention is preferably solvent-free because it reacts and cures immediately after the ink impacts. If the solvent remains in the cured image, problems of solvent resistance deterioration and residual solvent VOC occur. Therefore, it is preferable in view of dispersion suitability that the dispersion medium is selected from a polymerizable compound, not a solvent, and a monomer having the lowest viscosity among them.

The dispersion of the pigment is carried out by adjusting the average particle diameter of the pigment particles to 0.
08-0.5 μm is preferable, and the maximum particle size is 0.3-10 μm, preferably 0.3-3 μm, the selection of pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are appropriately set. To do. By controlling the particle size, clogging of the head nozzle can be suppressed, and the ink storage stability, ink transparency, and curing sensitivity can be maintained.

In the ink according to the present invention, the coloring material concentration is preferably 1% by mass to 10% by mass of the total ink.

Various additives other than those described above can be used in the ink according to the present invention. For example, in order to enhance the storage stability of the ink composition, a polymerization inhibitor of 200 to
20000 ppm can be added. Since it is preferable that the ultraviolet curable ink is heated and reduced in viscosity before being ejected, it is preferable to add a polymerization inhibitor in order to prevent head clogging due to thermal polymerization. In addition to these, if necessary, a surfactant, a leveling additive, a matting agent, a polyester resin for adjusting the film physical properties, a polyurethane resin, a vinyl resin, an acrylic resin, a rubber resin,
Waxes can be added. In order to improve the adhesion to the recording medium, it is also effective to add an extremely small amount of organic solvent. In this case, it is effective to add it within a range that does not cause problems of solvent resistance and VOC.
It is in the range of ~ 5%, preferably 0.1-3%.
In addition, a radical polymerizable monomer and an initiator are combined,
It is also possible to use a radical / cation hybrid type curing ink.

In the image forming method of the present invention, the ink composition is ejected onto a recording material by an ink jet recording method to draw an image, and then the active ray such as ultraviolet rays is irradiated to cure the ink.

In the present invention, the total ink film thickness after the ink has landed and is irradiated with actinic rays and cured is 2 to 20 μm.
Is preferred. In the actinic ray-curable inkjet recording in the screen printing field, the total ink film thickness is 20μ.
Although the current value is more than m, in the flexible packaging printing field where the recording material is often a thin plastic material, not only the curling and wrinkling problems of the recording material described above but also the stiffness and texture of the entire printed matter It cannot be used because it has the problem of changing.

As the ink ejection conditions, it is preferable in terms of ejection stability that the recording head and the ink are heated to 35 to 100 ° C. and then ejected. Actinic ray curable ink has a wide range of viscosity fluctuation due to temperature fluctuations, and viscosity fluctuations directly affect the droplet size and droplet ejection speed, causing image quality deterioration. It is necessary to keep. The control range of the ink temperature is set temperature ± 5 ° C, preferably set temperature ± 2 ° C, and more preferably set temperature ± 1 ° C.

Further, in the present invention, it is preferable that the amount of droplets ejected from each nozzle is 2 to 15 pl. In order to form a high-definition image, it is necessary that the droplet amount is within this range. However, when ejecting with this droplet amount, the ejection stability described above becomes particularly severe, and an acid multiplying agent is essential. Become.

In the image recording method of the present invention, the irradiation condition of the generated light rays is 0.001 to 2.0 after the ink has landed.
Irradiation with actinic rays is preferably performed for 2 seconds, more preferably 0.001 to 1.0 seconds. In order to form a high-definition image, it is especially important that the irradiation timing is as early as possible.

As a method for irradiating actinic rays, the basic method is disclosed in JP-A-60-132767.
According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain time has elapsed after the ink has landed. Furthermore,
Curing is completed by another light source that is not driven. US Pat. No. 6,145,979 discloses, as an irradiation method, a method using an optical fiber and a method of irradiating a recording section with UV light by applying a collimated light source to a mirror surface provided on the side surface of the head unit. There is. Any of these irradiation methods can be used in the image forming method of the present invention.

Further, the irradiation of the active ray is divided into two stages. First, the active ray is irradiated by the above-mentioned method within 0.001 to 2.0 seconds after the ink has landed, and after the completion of all printing, the active ray is further irradiated. The method of irradiating is also one of the preferable embodiments. By dividing the irradiation of actinic rays into two stages, it becomes possible to further suppress the shrinkage of the recording material that occurs during ink curing.

Conventionally, in the UV ink jet system, in order to suppress dot spread and bleeding after ink landing, it has been usual to use a high illuminance light source whose total power consumption of the light source exceeds 1 kW · hr. However, when these light sources are used, the shrinkage of the recording material is so large that it cannot be practically used particularly in printing such as shrink labels. In the present invention, by using an actinic ray having the highest illuminance in the wavelength region of 280 to 320 nm, a high-definition image can be formed even when using a light source having a total power consumption of 1 kW · hr or more, and a recording material The shrinkage can be kept within an acceptable level for practical use. Further, in the present invention, the total power consumption of the light source for irradiating the actinic ray is 1 kW.
It is preferably less than hr. Total power consumption is 1kW
Examples of the light source less than hr include fluorescent tubes, cold cathode tubes, LE
However, the present invention is not limited to these.

As the recording material that can be used in the present invention, in addition to ordinary non-coated paper, coated paper and the like, various non-absorbent plastics and films thereof used for so-called soft packaging can be used. Examples of the film include PET film, OPS film, OPP film, ONy film, PVC film, PE film, and TAC film. Other plastics include polycarbonate, acrylic resin, ABS, polyacetal, PVA,
Rubber etc. can be used. Further, it is also applicable to metals and glasses. Among these recording materials, the constitution of the present invention is effective especially when an image is formed on a PET film, an OPS film, an OPP film, an ONy film, or a PVC film, which can be shrunk by heat.
In these base materials, not only the film is easily curled and deformed due to the curing shrinkage of the ink and the heat generated during the curing reaction, but also the ink film is difficult to follow the shrinkage of the base material.

It has been a problem in the past that the surface energies of these various plastic films are greatly different and the dot diameter after the ink has landed varies depending on the recording material. With the constitution of the present invention, the surface energy including the OPP film having a low surface energy, the OPS film, and the PET having a relatively large surface energy is 35.
A good and high-definition image can be formed on a wide range of recording materials of -60 dyn / cm.

In the present invention, a long material (web) is used in terms of recording material costs such as packaging costs and production costs, print production efficiency, and compatibility with prints of various sizes.
It is advantageous to use different recording materials.

[0097]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

Example 1 << Preparation of Ink Compositions >> Ink composition sets 1 to 3 having the constitutions shown in Tables 1 to 3 were prepared.

[0099]

[Table 1]

[0100]

[Table 2]

[0101]

[Table 3]

The abbreviations of the inks shown in Tables 1 to 3 and details of each compound are as follows. K: Dark black ink C: Dark cyan ink M: Dark magenta ink Y: Dark yellow ink Lk: Light black ink Lc: Light cyan ink Lm: Light magenta ink Ly: Light yellow ink color material 1: C.I. I. pigment Black 7 coloring material 2: C.I. I. Pigment Blue 15: 3 Colorant 3: C.I. I. pigment Red 57: 1 coloring material 4: C.I. I. Pigment Yellow 13 Celoxide 2081: Daicel Chemical Industries Celoxide 3000: Daicel Chemical Industries V-1: RAPI-CURE DVE-3 ISPE Japan OXT-212: Toagosei Kagaku OXT-221: Toagosei Chemical Company Akpress 11: Nippon Chemix SP152: Asahi Denka Kagaku CS7102: Nippon Soda * 1: Triethanolamine * 2: N-Ethyldiethanolamine * 3: Tributylamine

[0103]

[Chemical 19]

<Inkjet image forming method> An inkjet recording apparatus equipped with a piezo type inkjet nozzle was loaded with each of the ink composition sets prepared above, and Table 4
Width 600 mm, length 10 with surface energy described in
The following image recordings were continuously performed on each recording material having a length of 00 m. The ink supply system consists of an ink tank, a supply pipe, an anterior chamber ink tank in front of the head, piping with a filter, and a piezo head.
The temperature was adjusted to. The piezo head unit was driven so that multi-size dots of 2 to 15 pl could be ejected at a resolution of 720 × 720 dpi, and each ink was ejected continuously. 0.2 seconds after landing, curing treatment was performed under the irradiation conditions shown in Table 4. After recording, the total ink film thickness was measured and found to be in the range of 2.3 to 13 μm. The term "dpi" in the present invention means the number of dots per 2.54 cm.

[0105]

[Table 4]

Details of the abbreviations of the recording materials shown in Table 4 are as follows. OPP: oriented polypropylen
e PET: polyethylene terephth
ATE ONy: Oriented nylon PVC: polyvinyl chloride The details of the irradiation light source shown in Table 4 are as follows.

Irradiation light source 1: Electrodeless UV lamp (F450 series manufactured by Fusion UV Systems Japan Co., Ltd.)
Electric power: 3 kW / hr) Irradiation light source 2: Cold-cathode tube (custom-made product made by Hibeck Co., power: less than 1 kW-hr) Irradiation light source 3: Fluorescent lamp (custom-made product from Nippon Electric Co., Ltd. Power:
<1 kW · hr) << Evaluation of Inkjet-Recorded Image >> The following evaluations were performed on each image recorded by the image forming method. Each evaluation was carried out on a 10 m sample, a 100 m sample and a 500 m sample after printing of continuously discharged image recording.

(Evaluation of character quality) For each color of Y, M, C, and K, 6-point MS Mincho typeface characters were printed at the target density, and the rubbing of the letters was observed under a magnifying glass, and the following criteria were used. Therefore, the character quality was evaluated.

⊚: No rustling ○: Slight rustling is observed Δ: Roughness is recognized, but it can be discerned as characters X: The rustling is severe and the characters are so faint that they cannot be used (color mixing ( Evaluation of bleeding) Each color of Y, M, C, and K is printed with a 6-point MS Mincho typeface character at a target density, each adjacent color dot is magnified with a loupe, and the bleeding condition is visually observed. The color mixture was evaluated according to the standard.

⊚: Adjacent dot shapes maintain a perfect circle and no blurring ○: Adjacent dot shapes maintain a nearly perfect circle and almost no blurring Δ: Adjacent dot shapes are slightly blurred and the dot shapes are slightly distorted However, the level is within an allowable range. X: Adjacent dots are bleeding and mixed with each other, which is a level that cannot be used (evaluation of wrinkles and curls on printed matter) 10 m, 100 m and 5
After printing for 00 m, each printed matter was visually observed for wrinkles and curls due to irradiation and curing, and evaluated according to the following evaluation criteria.

◯: No wrinkles or curls are generated, which is good Δ: Some wrinkles or curls are observed, but is in a practically acceptable range ×: Strong wrinkles or curls are observed in the printed matter, which is practical Table 5 shows each evaluation result obtained by the above problems.

[0112]

[Table 5]

As is clear from Table 5, the image recording method using the ink composition set according to the present invention is excellent in character quality, does not cause color mixing, and produces a high-definition image for all recording materials. It can be seen that the printed matter can be recorded and there is no wrinkle or curl in the printed matter.

Example 2 << Preparation of Ink Compositions >> Ink composition sets 4 to 6 having the constitutions shown in Tables 6 to 8 were prepared.

[0115]

[Table 6]

[0116]

[Table 7]

[0117]

[Table 8]

Details of each compound shown in Tables 6 to 8 are as follows. K: Dark black ink C: Dark cyan ink M: Dark magenta ink Y: Dark yellow ink Lk: Light black ink Lc: Light cyan ink Lm: Light magenta ink Ly: Light yellow ink W: White ink color material 1: C.I. I. pigment Black 7 coloring material 2: C.I. I. Pigment Blue 15: 3 Colorant 3: C.I. I. pigment Red 57: 1 coloring material 4: C.I. I. Pigment Yellow 13 Coloring Material 5: Titanium Oxide (Anatase Type Average Particle Size 0.20
μm) Celoxide 2081: manufactured by Daicel Chemical Industries, Ltd. (partly,
* A in the table) Celoxide 3000: manufactured by Daicel Chemical Industries, Ltd. (partly,
(* B in the table) OXT-212: Toa Gosei Kagaku OXT-221: Toa Gosei Kagaku SP152: Asahi Denka Kagaku Kogyo CS7102: Nippon Soda * 2: N-ethyldiethanolamine * 4: Tripropylamine * 5: Diethylthioxanthone

[0119]

[Chemical 20]

<Inkjet image forming method> An inkjet recording apparatus equipped with a piezo type inkjet nozzle was loaded with each of the ink composition sets prepared above, and Table 9
Width 600 mm, length 10 with surface energy described in
The following image recordings were continuously performed on each recording material having a length of 00 m. The ink supply system consists of an ink tank, a supply pipe, a front chamber ink tank just before the head, a pipe with a filter, and a piezo head.
The temperature was adjusted to. The piezo head unit was driven so that multi-size dots of 2 to 15 pl could be ejected at a resolution of 720 × 720 dpi, and each ink was ejected continuously. 0.15 seconds after landing, curing treatment was performed under the irradiation conditions shown in Table 9. After recording, the total ink film thickness was measured and found to be in the range of 2.3 to 19.6 μm.

[0121]

[Table 9]

The details of the abbreviations of the recording materials shown in Table 9 are as follows. OPP: oriented polypropylen
e PET: polyethylene terephth
ate ONy: Oriented nylon Shrink PVC: Shrink polyvinyl
chloride Shrink OPS: Shrinked oriented
polystyrene The details of the irradiation light source shown in Table 9 are as follows.

Irradiation light source 4: Black light (custom-made product manufactured by Nippon Electric Co., power: less than 1 kW.hr) Irradiation light source 5: Cold cathode tube (custom-made product manufactured by Hibeck, power: less than 1 kW.hr) Irradiation light source 6: LED (Custom-made product made by Nichia Corporation, power: less than 1 kW · hr) << Evaluation of inkjet recording image >> For each image recorded by the above-mentioned image forming method, a sample of 10 m after printing of a continuously ejected image record, a sample of 100 m According to the method described in Example 1, the quality of characters, color mixing, wrinkles on printed matter, and curl were evaluated for the samples of 500 m and 500 m, and the obtained results are shown in Table 10.

[0124]

[Table 10]

As is clear from Table 10, as with the results of Example 1, the image recording method using the ink composition set containing the white ink according to the present invention showed good character quality for all recording materials. It can be seen that it is excellent, it is possible to record a high-definition image without causing color mixing, and there is no wrinkling or curling of the printed matter.

[0126]

INDUSTRIAL APPLICABILITY According to the present invention, an ink jet recording having excellent character quality, capable of recording a high-definition image without generation of color mixture, and generation of wrinkles and curls of printed matter can be performed on any recording material. The image forming method, the printed matter, and the recording apparatus according to the method can be provided.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA04 EC72 FC01 FC06 FD20                 2H086 BA01 BA05 BA15 BA17 BA41                       BA54 BA55 BA59                 4J039 AD21 AE05 AE07 AE11 BC05                       BC06 BC33 BC40 BC41 BC44                       BC50 BC52 BC54 BC55 BC56                       BC58 BC59 BC65 BC74 BE27                       EA05 EA18 EA44 EA47 FA02                       GA24

Claims (12)

[Claims] 1. An image forming method for ejecting an ink, which is cured by an actinic ray, onto a recording material in a recording head having at least one nozzle capable of selectively ejecting an ink droplet, wherein the ink generates photo-acid. Containing agents, and 2
An image forming method, characterized in that the ink is cured using an actinic ray having a maximum illuminance in a wavelength region of 80 to 320 nm. 2. The image forming method according to claim 1, wherein the photo acid generator is at least one sulfonium compound. 3. The image forming method according to claim 1, wherein the ink contains at least one oxetane compound as a photopolymerizable compound. 4. The image forming method according to claim 1, wherein at least one color of the ink is white ink. 5. From 0.001 after the ink has landed
The image forming method according to claim 1, wherein the actinic ray is irradiated for 2.0 seconds. 6. The image according to claim 1, wherein the ink has a total ink film thickness of 2 to 20 μm after the ink has landed and is irradiated with actinic rays to be cured. Forming method. 7. The image forming method according to claim 1, wherein the amount of ink droplets ejected from each nozzle of the recording head is 2 to 15 pl. 8. A non-absorptive recording material is used to claim 1.
7. A printed matter produced by the image forming method according to any one of 7 above. 9. The printed matter according to claim 8, wherein the surface energy of the non-absorbent recording material is 35 to 60 dyn / cm. 10. A recording apparatus which is used in the image forming method according to claim 1. 11. A recording apparatus, which is used for producing the printed matter according to claim 8 or 9. 12. The total power consumption of a light source for irradiating with actinic rays is less than 1 kW · hr.
Or the recording device according to item 11.