JP2007268788A - Method and equipment for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inkjet recording which is hardly affected by retardation of polymerization due to oxygen or moisture at the time when an image of a low density part is cured and polymerized by using a low illuminance light source. <P>SOLUTION: A recording solution containing at least a polymerizable compound and a treating solution different in composition from the recording solution being used, a droplet (I) of 100 pl or less consisting of the recording solution and a droplet (II) of 100 pl or less consisting of the treating solution are discharged onto a recording medium by an inkjet recording head, and after the discharge, they are polymerized and cured by low illuminance exposure wherein the illuminance on the surface of the recording medium is 1,000 mW/cm<SP>2</SP>or less, so as to form the image. On the occasion, the vertically projected area S1 of the droplet (I) to the recording medium, the vertically projected area S2 of the droplet (II) and the vertically projected area S3 of a superposed part of the droplets (I) and (II), in the low illuminance exposure, are in the relations of S1<S2 and S1=S3 in this inkjet recording method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording method using an ink for ultraviolet curable ink jet recording, and an ink jet recording apparatus, and more specifically, ink jet recording excellent in curability even when a small ultraviolet light source such as an LED is used. The present invention relates to a method and an ink jet recording apparatus using the method.

  An ink jet system that ejects ink from an ink ejection port such as a nozzle is small and inexpensive, and is used in many printers because it can form an image in a non-contact manner on a recording medium. Among these ink jet systems, the piezoelectric ink jet system that ejects ink using deformation of piezoelectric elements and the thermal ink jet system that ejects ink using the boiling phenomenon of ink due to thermal energy are excellent in high resolution and high speed printability. Has characteristics.

  In the printing field using the ink jet system, there is an increasing demand for high speed and high image quality when printing on a non-permeable recording medium such as plain paper or plastic. However, an image on a non-permeable recording medium can be obtained by using an aqueous ink (an ink mainly composed of a colorant and water) or an oil-based ink (an ink mainly composed of a colorant and a volatile organic solvent). When it is intended to form the ink droplets, it takes time to dry the droplets after printing, so that the ink droplets spread or ooze and hinder sharp image formation. Further, as another problem when printing on a non-permeable recording medium with these inks, it is known that the fixing property of the colorant to the recording medium is poor and the abrasion resistance and water resistance are poor. .

In order to improve the fixability and bleeding in the non-penetrable recording medium as described above, as one of the methods for promoting the curing of the ink and fixing it to the recording medium, an ultraviolet ray that is cured and fixed by ultraviolet rays. A curable ink jet recording ink has been proposed.
As an ultraviolet irradiation means widely used in conventional ultraviolet curable ink jet printers, a high pressure ultraviolet lamp having high ultraviolet illuminance and good ink curability is known. However, the high-pressure ultraviolet lamp generates a large amount of heat because most of the applied power is converted into heat. Therefore, in order to secure sufficient illuminance for curing the ink, it is necessary to increase the power source capacity, resulting in an increase in cost. Furthermore, since it is necessary to provide a duct for exhaust heat, there is a problem that not only the manufacturing cost increases but also the printer becomes large.
Furthermore, another problem when using a high-pressure ultraviolet lamp is not only the ink curing shrinkage and the heat generated during the curing reaction, but also the heat generated from the irradiating ultraviolet lamp causes curling and undulation of the recording material. The value as a printed matter is reduced.

As means for solving the above-described enlargement of the printer and deformation at the time of curing, an ultraviolet curable inkjet recording method using an LED and a printer are disclosed (for example, see Patent Documents 1 to 3).
However, when an LED is used as compared with a high-pressure ultraviolet lamp, the illuminance on the recording medium is often lowered. Therefore, when curing UV-curable ink for inkjet recording using LED, radical polymerization type UV curable ink has an effect of inhibition of polymerization by oxygen, and cationic polymerization type UV curable ink has inhibition of polymerization by moisture (humidity). It is easily affected by As a result, in low density areas where the ink droplets are in contact with the air at large areas (images formed without overlapping areas between adjacent ink droplets on the recording medium), poor curing is a major problem. It has become.
Moreover, even if it is going to obtain illumination intensity equivalent to a high pressure ultraviolet lamp using LED, it is technically difficult, and since it is necessary to install many light sources, it is disadvantageous in terms of cost.
JP 2004-243548 A International Publication No. WO03 / 057488 Pamphlet JP 2005-254560 A

The present invention has been made in view of the above-described conventional problems, and an object thereof is to achieve the following object. That is,
An object of the present invention is to use a light source with low illuminance such as an LED to cure and polymerize an image of a low density portion (an image formed with an ink droplet that does not overlap with an adjacent ink droplet). An object of the present invention is to provide an ink jet recording method which is not easily affected by polymerization inhibition by oxygen or moisture, and an ink jet recording apparatus using the ink jet recording method.
Specifically, an independent ink liquid having a volume of 100 pl or less even when low-illuminance exposure (illuminance on the recording medium surface: 1000 mW / cm ² or less) is performed in the atmosphere under high humidity (70% RH or more). Provided is an ink jet recording method in which a droplet is cured and polymerized even with an exposure energy integrated amount of 30 mJ / cm ² or less.

The means for solving the above problems are as follows. That is,
<1> A recording liquid containing at least a colorant and a polymerizable compound, and a treatment liquid substantially not containing a colorant, and comprising 100 pl or less of the recording liquid (I) and the treatment liquid. A droplet (II) of 100 pl or less is ejected onto a recording medium by an ink jet recording head, and after the ejection, the surface of the recording medium is polymerized and cured by low illumination exposure with an illuminance of 1000 mW / cm ² or less. An ink jet recording method for forming an image, comprising:
The vertical projection area S1 of the droplet (I) onto the recording medium, the vertical projection area S2 of the droplet (II), and the droplet (I) and the droplet (II) at the time of low-illuminance exposure The vertical projection area S3 of the overlapping portion is S1 <S2 and S1 = S3.

<2> The inkjet recording method according to <1>, wherein the relationship between the surface tension γ1 of the recording liquid and the surface tension γ2 of the treatment liquid is γ2 <γ1 (mN / m).

<3> The inkjet recording method according to <1> or <2>, wherein a polymerization initiator is contained in at least one of the recording liquid and the treatment liquid.

<4> The inkjet recording method according to any one of <1> to <3>, wherein the polymerizable compound is water-insoluble.

<5> An inkjet recording apparatus using the inkjet recording method according to any one of <1> to <4>.

  According to the present invention, when a light source with low illuminance such as an LED is used to cure and polymerize an image of a low density portion (an image formed by an ink droplet that does not overlap with an adjacent ink droplet), It is possible to provide an ink jet recording method which is not easily affected by polymerization inhibition by oxygen or moisture, and an ink jet recording apparatus using the ink jet recording method.

The inkjet recording method of the present invention uses at least a recording liquid containing a colorant and a polymerizable compound, and a treatment liquid that does not substantially contain a colorant. A droplet (II) of 100 pl or less made of the treatment liquid is ejected onto a recording medium by an ink jet recording head, and after the ejection, low-illuminance exposure with an illuminance on the recording medium surface of 1000 mW / cm ² or less is performed. An ink jet recording method for forming an image by polymerizing and curing, wherein a vertical projection area S1 of the droplet (I) onto a recording medium at the time of low illumination exposure, a vertical projection area S2 of the droplet (II), The vertical projected area S3 of the overlapping portion of the droplet (I) and the droplet (II) is S1 <S2 and S1 = S3.
By using the ink jet recording method of the present invention as described above, when a low-illuminance light source such as an LED is used as an ultraviolet irradiation device, a low-density portion (an image formed with ink droplets that do not overlap with adjacent ink droplets). It is possible to reduce curing failure due to polymerization inhibition due to oxygen (such as radical polymerization type ink) generated in the water and moisture (such as cationic polymerization type ink).
First, the ink set (recording liquid, processing liquid) used in the ink jet recording method of the present invention will be described.

(Recording liquid and processing liquid)
The ink set used in the present invention is composed of a recording liquid containing at least a colorant and a polymerizable compound, and a treatment liquid that does not substantially contain a colorant. From the recording liquid and the treatment liquid, droplets ( I), droplet (II) is obtained. From the viewpoint of image definition, the volume of the droplet (I) and the droplet (II) is 100 pl or less, preferably 50 pl or less, more preferably 10 pl or less. In the printing, it is preferable that the droplet (I) is ejected after the droplet (II) is ejected. In the following description, the order of the droplet ejection is described as a premise.
The recording liquid containing at least the colorant and the polymerizable compound may be liquid at room temperature, but from the viewpoint of ink jetting appropriateness, the viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less. Preferably there is. Moreover, it is preferable that the composition of the polymerizable compound is 50% by mass or more and 98% by mass or less from the viewpoint of fixing the ink to a recording medium and preventing ink bleeding. In addition, when water or an aqueous solvent is included, fixing takes time, so that it is preferably non-aqueous.

The treatment liquid that does not substantially contain a colorant may be liquid at room temperature, but from the viewpoint of droplet ejection by inkjet, the viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less. It is preferable.
The phrase “substantially does not contain a colorant” does not exclude the inclusion of a colorless and transparent dye / pigment, or a very small amount that cannot be visually recognized. The allowable amount is preferably 1% by mass or less and particularly preferably not contained with respect to the total mass of the spread suppressing liquid.
Moreover, it is preferable that a process liquid contains a high boiling-point solvent from a viewpoint of discharge | emission suppression of a volatile organic compound (VOC).

(Polymerizable compound)
As described above, the recording liquid in the invention contains at least a polymerizable compound.
As the polymerizable compound, a known polymerizable or crosslinkable material such as a radical polymerization reaction, a cationic polymerization reaction, or a dimerization reaction can be applied.
Addition polymerizable compound having at least one ethylenically unsaturated double bond, epoxy compound, oxetane compound, oxirane compound, polymer compound having maleimide group in side chain, photodimerization adjacent to aromatic nucleus is possible Examples thereof include a polymer compound having a side chain of a cinnamyl group having an unsaturated double bond, a cinnamylidene group, a chalcone group, or the like.
The addition polymerizable compound having at least one ethylenically unsaturated double bond is selected from compounds having at least one terminal ethylenically unsaturated bond, more preferably two or more (monofunctional or polyfunctional compound). Is.
Specifically, it can be appropriately selected from those widely known in the industrial field according to the present invention, for example, monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof, and Those having a chemical form such as a copolymer of

  Specifically, the polymerizable compound preferably has a polymerizable group such as an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, or an internal double bond group (such as maleic acid) in the molecule. A compound having an acryloyl group or a methacryloyl group is preferable in that it can cause a curing reaction.

  Examples of the polyfunctional compound include a vinyl group-containing aromatic compound, an (meth) acrylate that is an ester of a divalent or higher alcohol and (meth) acrylic acid, an amide of a divalent or higher amine and (meth) acrylic acid. It can be obtained by combining (meth) acrylamide, polyester (meth) acrylate obtained by introducing (meth) acrylic acid into polycaprolactone, ester obtained by combining polybasic acid and dihydric alcohol, or coupling of alkylene oxide and polyhydric alcohol. Polyether (meth) acrylate in which (meth) acrylic acid is introduced into ether, (meth) acrylic acid is introduced into epoxy resin, or epoxy (meth) obtained by reacting a bivalent or higher alcohol with an epoxy-containing monomer Acrylate, urethane acrylate with urethane bond, amino resin Relate, acrylic resin acrylate, alkyd resin acrylate, spirane resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and photopolymerizable monomer, reaction product of waxes and polymerizable monomer, and the like. .

Among them, (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, epoxy acrylate, urethane acrylate, acrylic resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and the photopolymerizable monomer are preferable. Acrylate, polyester acrylate, polyether acrylate, epoxy acrylate, and urethane acrylate are particularly preferable.
In addition, in this specification, (meth) acrylic acid shows that it can take both acrylic acid and methacrylic acid.

  Specific examples of the polyfunctional compound include divinylbenzene, 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, 1, 6-acryloylaminohexane, hydroxypivalate ester neopentyl glycol diacrylate, polyester acrylate having a (meth) acryloyl group at the molecular chain end of a polyester having a molecular weight of 500 to 30,000 consisting of a dibasic acid and a dihydric alcohol, polyethylene glycol di An acrylate, an epoxy acrylate having a molecular weight of 450 to 30,000 having a bisphenol (A or S, F) skeleton, and a skeleton of a phenol novolac resin Epoxy acrylates amount from 600 to 30,000, the reaction product of a polyvalent isocyanate and a hydroxyl group (meth) acrylate monomer having a molecular weight of 350 to 30,000, and urethane modified products having urethane bonds and the like in the molecule.

Examples of monofunctional compounds include (meth) acrylate, styrene, acrylamide, vinyl group-containing monomers (vinyl esters, vinyl ethers, N-vinylamide, etc.), (meth) acrylic acid, and the like. , Acrylamide, vinyl esters and vinyl ethers are preferable, and (meth) acrylate and acrylamide are particularly preferable.
The polymerizable compound may be unsubstituted or may have a substituent, and examples of the substituent that can be introduced include a halogen atom, a hydroxyl group, an amide group, and a carboxylic acid group.

  Specific examples of the monofunctional compound include hydroxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, 2-acryloyloxyethyl phosphate, allyl acrylate, N, N-dimethylaminoethyl acrylate, N, N- Dimethylacrylamide, N, N-diethylaminopropylacrylamide, N-butoxymethylacrylamide, acryloylmorpholine, 2-hydroxyethyl vinyl ether, N-vinylformamide, N-vinylacetamide, 2-cyclohexylcarbamoyloxyethyl acrylate, polybutyl acrylate moiety on ester An acrylate having a polydimethylsiloxane moiety in an ester

  Examples of the cationic polymerizable monomer used in the present invention include JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, and JP-A-2001-2001. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like described in each publication such as 220526.

Examples of the epoxy compound include aromatic epoxides and alicyclic epoxides.
Examples of monofunctional epoxy compounds that can be used in the present invention include, for example, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monooxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxymethylcyclohexene oxide, 3 -Vinylcyclohexene oxide etc. are mentioned.

Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, and brominated bisphenol. S diglycidyl ether, epoxy novolac resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxy 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclo) Xylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6 '-Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate) , Epoxyhexahydrophthalate dioctyl, epoxyhexahydrophthalate di-2-ethylhexyl, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether Glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8- Examples include diepoxyoctane and 1,2,5,6-diepoxycyclooctane.
Among these epoxy compounds, aromatic epoxides and alicyclic epoxides are preferable from the viewpoint of excellent curing speed, and alicyclic epoxides are particularly preferable.

  Examples of monofunctional vinyl ethers that can be used in the present invention include, for example, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether, lauryl vinyl ether, cyclohexyl vinyl ether, Cyclohexylmethyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether Methoxypolyethylene Coal vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, Examples include chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxypolyethylene glycol vinyl ether, and the like.

Examples of polyfunctional vinyl ethers include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, and bisphenol F. Divinyl ethers such as alkylene oxide divinyl ether; trimethylolethane trivinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipentaerythritol Hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, propylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, propylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, propylene oxide addition Examples thereof include polyfunctional vinyl ethers such as pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether, and propylene oxide-added dipentaerythritol hexavinyl ether.
As the vinyl ether compound, a di- or trivinyl ether compound is preferable from the viewpoints of curability, adhesion to a recording medium, surface hardness of the formed image, and the like, and a divinyl ether compound is particularly preferable.

The oxetane compound in the present invention refers to a compound having an oxetane ring, and a known oxetane compound is arbitrarily selected as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. Can be used.
The compound having an oxetane ring that can be used in the ink set according to the present invention is preferably a compound having 1 to 4 oxetane rings in the structure. By using such a compound, it becomes easy to maintain the viscosity of the ink composition in a good handling property range, and it is possible to obtain high adhesion of the cured ink to the recording medium. .

  Examples of the monofunctional oxetane used in the present invention include, for example, 3-ethyl-3-hydroxymethyloxetane, 3- (meth) allyloxymethyl-3-ethyloxetane, (3-ethyl-3-oxetanylmethoxy) methyl Benzene, 4-fluoro- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, 4-methoxy- [1- (3-ethyl-3-oxetanylmethoxy) methyl] benzene, [1- (3- Ethyl-3-oxetanylmethoxy) ethyl] phenyl ether, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl- 3-Oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl) 3-oxetanylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether, dicyclopentadiene (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyloxyethyl (3-ethyl-3-oxetanylmethyl) ) Ether, dicyclopentenyl (3-ethyl-3-oxetanylmethyl) ether, tetrahydrofurfuryl (3-ethyl-3-oxetanylmethyl) ether, tetrabromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2- Tetrabromophenoxyethyl (3-ethyl-3-oxetanylmethyl) ether, tribromophenyl (3-ethyl-3-oxetanylmethyl) ether, 2-tribromophenoxyethyl (3-ethyl-3-oxetanyl) Til) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, butoxyethyl (3-ethyl-3-oxetanylmethyl) ether, Examples include pentachlorophenyl (3-ethyl-3-oxetanylmethyl) ether, pentabromophenyl (3-ethyl-3-oxetanylmethyl) ether, bornyl (3-ethyl-3-oxetanylmethyl) ether, and the like.

  Examples of the polyfunctional oxetane include, for example, 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) Bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1 , 3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, Triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl -3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3- Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3 -Oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl) 3-oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis ( 3-ethyl-3-oxetanylmethyl) ether, ditrimethylolpropanetetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis ( 3-ethyl-3-oxetanylmethyl) ether, EO-modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified hydrogenated bisphenol A bis (3-ethyl) And polyfunctional oxetanes such as ru-3-oxetanylmethyl) ether and EO-modified bisphenol F (3-ethyl-3-oxetanylmethyl) ether.

The compound having such an oxetane ring is described in detail in the above-mentioned JP-A No. 2003-341217, paragraph numbers [0021] to [0084], and the compounds described therein can be suitably used in the present invention.
Among the oxetane compounds used in the present invention, it is preferable to use a compound having 1 to 2 oxetane rings from the viewpoint of the viscosity and tackiness of the ink composition.

  In the present invention, when an oxetane compound is used, it is preferable to use in combination with at least one compound selected from an epoxy compound and a vinyl ether compound.

A polymeric compound may be used individually by 1 type, and may be used in combination of 2 or more type. However, since fixing takes time when water or an aqueous solvent is included, the polymerizable compound is preferably water-insoluble.
The content in the recording liquid (each droplet) is 50 to 98 mass with respect to the total mass of the recording liquid (each droplet) from the viewpoint of fixability to a recording medium and prevention of ink bleeding. % Is preferable, a range of 40 to 95% by mass is more preferable, and a range of 50 to 90% by mass is particularly preferable. By setting this range, it is preferable to set the range because the fixability to a recording medium can be improved and ink bleeding can be prevented.
The content of the polymerizable compound in the recording liquid (each liquid droplet) is the total solid content in the recording liquid (each liquid droplet) from the viewpoint of fixability to a recording medium and prevention of ink bleeding. Mass), a range of 50 to 99.6% by mass is preferable, a range of 70 to 99.0% by mass is more preferable, and a range of 80 to 99.0% by mass is more preferable. By setting this range, it is preferable to set the range because the fixability to a recording medium can be improved and ink bleeding can be prevented.

(Coloring agent)
As described above, the recording liquid in the present invention contains at least a colorant.
The colorant is not particularly limited and can be appropriately selected from known water-soluble dyes, oil-soluble dyes, pigments and the like. Among them, the recording liquid and the processing liquid according to the present invention are preferably composed of a water-insoluble organic solvent system from the viewpoint of the effect of the present invention, and an oil-soluble dye that is easily dispersed and dissolved in a water-insoluble medium, Preference is given to using pigments.
Hereinafter, the oil-soluble dye and pigment suitable for the present invention will be mainly described.

~ Oil-soluble dye ~
There is no restriction | limiting in particular as oil-soluble dye, Any things can be selected and used. Hereinafter, oil-soluble dyes are exemplified for each hue.
Examples of yellow dyes include phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; open-chain active methylene compounds as coupling components. Azomethine dyes; methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and the like. Other dye species include quinophthalone dyes, nitro / nitroso dyes, Examples include acridine dyes and acridinone dyes.

  Examples of magenta dyes include aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; azomethine dyes having pyrazolones and pyrazolotriazoles as coupling components; arylidene dyes, styryl dyes, and merocyanine dyes Methine dyes such as oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, quinone dyes such as naphthoquinone, anthraquinone and anthrapyridone, condensed polycyclic dyes such as dioxazine dyes Etc.

  Examples of cyan dyes include indoaniline dyes, indophenol dyes, or azomethine dyes having pyrrolotriazoles as coupling components; polymethine dyes such as cyanine dyes, oxonol dyes, and merocyanine dyes; diphenylmethane dyes, triphenylmethane dyes, Carbonium dyes such as xanthene dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components, and indigo / thioindigo dyes.

  Each of the dyes may exhibit yellow, magenta, and cyan colors only after a part of the chromophore group is dissociated. In this case, the counter cation is an alkali metal or an inorganic substance such as ammonium. Or an organic cation such as pyridinium or quaternary ammonium salt, or a polymer cation having such a cation in a partial structure.

  When an oil-soluble dye is used as the colorant, the content of the oil-soluble dye in the recording liquid is preferably in the range of 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content. 0.2 to 6% by mass is preferable. Moreover, as content in each liquid of an oil-soluble dye in case an oil-soluble dye is contained in a process liquid, the range of 0-1 mass% is preferable with respect to the total solid mass.

~ Pigment ~
The pigment preferably used in the present invention will be described.
The pigment is not particularly limited, and all commercially available organic pigments and inorganic pigments, and those obtained by dyeing resin particles with a dye can be used. Furthermore, commercially available pigment dispersions and surface-treated pigments, for example, pigments dispersed in an insoluble resin or the like as a dispersion medium, or those obtained by grafting a resin on the pigment surface, etc., impair the effects of the present invention. It can be used as long as it is not.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Specific examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow AAA, etc.), C.I. I. Disazo pigments such as C.I. Pigment Yellow 17; I. Non-benzidine type azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Condensed azo pigments such as CI Pigment Yellow 95 (Condensed Azo Yellow GR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as CI Pigment Yellow 18 (Thioflavin Lake, etc.), anthraquinone pigments such as Flavantron Yellow (Y-24), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), and quinophthalone yellow Quinophthalone pigments such as (Y-138), isoindoline pigments such as isoindoline yellow (Y-139), C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. And metal complex salt azomethine pigments such as CI Pigment Yellow 117 (copper azomethine yellow, etc.).

  C. As a thing which exhibits red or magenta color, C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Azo lake pigments such as C.I. Pigment Red 57: 1 (Brilliant Carmine 6B); I. Condensed azo pigments such as C.I. Pigment Red 144 (condensed azo red BR, etc.); I. Acidic dye lake pigments such as C.I. Pigment Red 174 (Phloxine B Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G 'lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as C.I. Pigment Red 194 (perinone red, etc.); I. Perylene pigments such as C.I. Pigment Red 149 (perylene scarlet, etc.); I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Quinacridone pigments such as CI Pigment Red 122 (quinacridone magenta, etc.); I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. And alizarin lake pigments such as CI Pigment Red 83 (Mada Lake, etc.).

  As a pigment exhibiting blue or cyan, C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Phthalocyanine pigments such as C.I. Pigment Blue 15 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1).

As a pigment exhibiting green, C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. And azo metal complex pigments such as CI Pigment Green 8 (Nitroso Green).
As a pigment exhibiting an orange color, C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. And anthraquinone pigments such as CI Pigment Orange 51 (dichloropyrantron orange).

Examples of the black pigment include carbon black, titanium black, and aniline black.
Specific examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), Strontium titanate (SrTiO ₃ , so-called titanium strontium white) or the like can be used.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

For dispersing the colorant, for example, a dispersing device such as a ball mill, a sand mill, an attritor, a roll mill, a jet mill, a homogenizer, a paint shaker, a kneader, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, or a wet jet mill is used. be able to.
When dispersing the colorant, a commercially available dispersant can be used. As the dispersant, a polymer dispersant is preferable. Examples of the polymer dispersant include a polymer dispersant such as 4000 series manufactured by efka, Solsperse series manufactured by Zeneca, and a dispersbyk series manufactured by BYK-chemie. Moreover, it is also possible to use a synergist according to various pigments as a 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.

  As a dispersion medium for various components such as a colorant in the recording liquid, a solvent may be added, or the polymerizable compound which is a low molecular weight component without a solvent may be used as the dispersion medium. Is preferably an active energy ray-curable liquid, and is preferably solvent-free in order to cure after applying the recording liquid onto the recording medium. This is because if the solvent remains in the image formed from the cured recording liquid, the solvent resistance is deteriorated or a problem of VOC (Volatile Organic Compound) of the remaining solvent occurs. From such a viewpoint, it is preferable to use a polymerizable compound as the dispersion medium, and in particular, to select a polymerizable compound having the lowest viscosity from the viewpoint of improving dispersibility and handling properties of the ink composition.

The average particle diameter of the colorant used here is preferably from 0.01 to 0.4 μm, more preferably from 0.02 to 0.2 μm, because the finer the particle, the better the color developability. (A) Selection of colorant, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so that the maximum particle size is 3 μm or less, preferably 1 μm or less. By controlling the particle size, clogging of the head nozzle can be suppressed, and the storage stability of the recording liquid, the transparency of the processing liquid, and the curing sensitivity can be maintained. In the present invention, by using the dispersant having excellent dispersibility and stability, a uniform and stable dispersion can be obtained even when a fine particle colorant is used.
The particle diameter of the colorant in the droplet (I) can be measured by a known measurement method. Specifically, it can be measured by a centrifugal sedimentation light transmission method, an X-ray transmission method, a laser diffraction / scattering method, and a dynamic light scattering method. In the present invention, a value obtained by measurement using a laser diffraction / scattering method is employed.
The concentration of the colorant is preferably 50% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and particularly preferably 2% by mass or more and 20% by mass or less. On the other hand, the addition concentration of the colorant in the treatment liquid is preferably 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably no colorant is contained in the treatment liquid.

(Relationship between surface tension of recording liquid and processing liquid)
Before the droplet (I) containing at least a polymerizable compound is deposited on the recording medium, a droplet (II) having a composition different from that of the droplet (I) is formed as the droplet (I). When an image is formed by applying to a wider area than the image to be printed (that is, S1 <S2), a distorted image may be obtained due to bleeding of a recording droplet or enlargement of the droplet size. Thus, in order to form an excellent image free from image disturbance due to bleeding or enlargement of the recording liquid, the recording liquid and the treatment liquid included in the ink set for ink jet recording of the present invention are as follows: It is preferable to satisfy all of B) and (C).

(A) The surface tension of the treatment liquid is smaller than the surface tension of any recording liquid included in the ink set for ink jet recording.
(B) At least one of the surfactants contained in the treatment liquid is
γs (0) −γs (saturated)> 1 mN / m
Satisfy the relationship.
(C) The surface tension of the treatment liquid is
γs <(γs (0) + γs (saturation) maximum) / 2
Satisfy the relationship.

  Here, γs is the value of the surface tension of the treatment liquid. γs (0) is the value of the surface tension of the liquid component excluding all the surfactants in the treatment liquid. γs (saturation) is the surface of the liquid component that becomes saturated when one of the surfactants contained in the treatment liquid is added to the liquid component and the concentration of the surfactant is increased. The value of tension. The γs (saturation) maximum is the maximum value of γs (saturation) obtained for all surfactants satisfying the condition (B) among the surfactants contained in the treatment liquid.

(Condition (A))
In the present invention, as described above, in order to form a recording liquid dot of a desired size on a recording medium, the surface tension γs of the processing liquid is set to any of the recording liquids included in the ink set for ink jet recording. The surface tension is preferably smaller than γk.
Further, from the viewpoint of more effectively preventing the expansion of the recording liquid dots from the landing to the exposure, γs <γk-3 (mN / m) is more preferable, and γs <γk-5 (mN / m) is particularly preferable. preferable.

When printing a full-color image, from the viewpoint of improving the sharpness of the image, the surface tension γs of the treatment liquid should be at least smaller than the surface tension of a recording liquid containing a colorant having high visibility. Is preferable, and it is more preferable that the surface tension of all the recording liquids included in the ink set for inkjet recording is smaller. Here, the colorant having high visibility includes a magenta, black, or cyan colorant.
Even if the surface tension γk of the recording liquid and the surface tension γs of the processing liquid satisfy the above relationship, if both values are less than 15 mN / m, it becomes difficult to form droplets during ink jetting. Non-ejection may occur. On the other hand, if it exceeds 50 mN / m, the wettability with the ink jet head may be deteriorated, resulting in a problem of non-ejection. Therefore, from the viewpoint of proper ejection, the surface tension γk of the recording liquid and the surface tension γs of the processing liquid are preferably 15 mN / m or more and 50 mN / m or less, more preferably 18 mN / m or more and 40 mN / m or less, and more preferably 20 mN / m or more. 38 mN / m or less is particularly preferable.
Here, the surface tension was measured at a liquid temperature of 20 ° C. by the Wilhelmy method using a commonly used surface tension meter (for example, Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z, etc.). Value.

(Conditions (B) and (C))
In the present invention, in order to form an ink dot having a desired size on a recording medium, the treatment liquid preferably contains at least one kind of surfactant. In this case, at least one of the surfactants contained in the treatment liquid preferably satisfies the following condition (B).
γs (0) −γs (saturation)> 1 mN / m Condition (B)
Furthermore, the surface tension of the treatment liquid preferably satisfies the following condition (C).
γs <(γs (0) + γs (saturation) maximum) / 2 Condition (C)

  Here, γs is the value of the surface tension of the treatment liquid. γs (0) is the value of the surface tension of the liquid component excluding all the surfactants in the treatment liquid. γs (saturation) is the surface of the liquid component that becomes saturated when one of the surfactants contained in the treatment liquid is added to the liquid component and the concentration of the surfactant is increased. The value of tension. The γs (saturation) maximum is the maximum value of γs (saturation) obtained for all surfactants satisfying the condition (B) among the surfactants contained in the treatment liquid.

  The γs (0) can be obtained by measuring the surface tension value of the liquid component excluding all the surfactants in the treatment liquid. The γs (saturation) is obtained when one surfactant among the surfactants contained in the treatment liquid is added to the liquid component and the concentration of the surfactant is increased by 0.01% by mass. Further, it is obtained by measuring the surface tension of the liquid component when the amount of change in surface tension becomes 0.01 mN / m or less.

Hereinafter, the γs (0), γs (saturated), and γs (saturated) maximum will be specifically described.
For example, the components constituting the treatment liquid (Example 1) are a high boiling point solvent (diethyl phthalate, manufactured by Wako Pure Chemical Industries), a polymerization initiator (TPO-L, exemplary compound-initiator-1), a fluorine-based surfactant. (Megafac F475, manufactured by Dainippon Ink and Chemicals), hydrocarbon surfactants (di-2-ethylhexyl sodium sulfosuccinate), γs (0), γs (saturated) ¹ (fluorine surfactant added) ), Γs (saturated) ² (when a hydrocarbon-based surfactant is added), γs (saturated), and γs (saturated) maximum are as follows.

That is, γs (0) is the surface tension value of the liquid component excluding all the surfactants in the treatment liquid, and was 36.7 mN / m. When the saturation value of the surface tension of the liquid component when the concentration is increased by adding a fluorosurfactant to the liquid component is γs (saturation) ¹ , the value is 20.2 mN / m. became. Similarly, when a hydrocarbon-based surfactant is added to the liquid component and the concentration is increased, the saturation value of the surface tension of the liquid component is γs (saturation) ^2, and the value is 30.5 mN. / M.

Since the treatment liquid (Example 1) contains two types of surfactants that satisfy the condition (B), γs (saturated) is a hydrocarbon when a fluorosurfactant is added (γs (saturated) ¹ ) and hydrocarbons. Two values (γs (saturated) ² ) can be taken when the system surfactant is added. From these, the γs (saturation) maximum is the maximum value of the γs (saturation) ¹ and γs (saturation) ² , and thus becomes the value of γs (saturation) ² .

From the above, they are summarized as follows.
γs (0) = 36.7 mN / m
γs (saturated) ¹ = 20.2 mN / m (when a fluorosurfactant is added)
γs (saturated) ² = 30.5 mN / m (when a hydrocarbon-based surfactant is added)
γs (saturation) maximum = 30.5 mN / m

From the above results, as the surface tension γs of the treatment liquid,
γs <(γs (0) + γs (saturation) maximum) /2=33.6 mN / m
It is preferable to satisfy the relationship.
Regarding the condition (C), from the viewpoint of more effectively preventing the expansion of ink droplets from landing to exposure, the surface tension of the treatment liquid is as follows:
γs <γs (0) −3 × {γs (0) −γs (saturated)} / 4
It is more preferable to satisfy the relationship
γs ≦ γs (saturated)
It is particularly preferable to satisfy this relationship.
Here, the surface tension was measured at a liquid temperature of 20 ° C. by the Wilhelmy method using a commonly used surface tension meter (for example, Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z, etc.). Value.

(Surfactant)
In the present invention, as described above, in order to form an ink dot of a desired size on a recording medium, the treatment liquid preferably contains at least one type of surfactant.
The surfactant can be selected from the following. Examples thereof include those described in JP-A Nos. 62-173463 and 62-183457. Specifically, for example, anionic surfactants such as dialkyl sulfosuccinates, alkyl naphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene -Nonionic surfactants such as polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used instead of the known surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compounds include fluorine surfactants, oily fluorine compounds (eg, fluorine oil) and solid fluorine compound resins (eg, tetrafluoroethylene resin). No. (columns 8 to 17) and those described in JP-A Nos. 62-135826.

  In particular, the surfactant used in the present invention is not limited to the above-mentioned surfactant, and may be any additive that has the ability to efficiently reduce the surface tension of the treatment liquid with respect to the added concentration. .

-Lipophilic solvent-
The oleophilic solvent is effective in preventing the occurrence of blurring of the image and line width variations such as fine lines in the image, and can adjust the sp value of the processing liquid to the above-described range.
“Lipophilic” refers to a compound having a solubility of 1 g or less with respect to 100 ml of water.

  The lipophilic solvent can be contained in the above-described recording liquid (recording liquid) with or without being contained in the processing liquid (processing liquid). Further, it may be contained in a liquid other than the processing liquid and the recording liquid.

  Examples of the oleophilic solvent include a high-boiling organic solvent described later, the above-described polymerizable compound, and the like, and a high-boiling organic solvent is preferable for avoiding nozzle solidification, etc. Is preferably a polymerizable compound.

(Polymerization initiator)
At least one of the recording liquid and the processing liquid preferably contains a polymerization initiator in order to accelerate the polymerization reaction quickly. The polymerization initiator preferably contains a polymerization initiator for radical polymerization or cationic polymerization, and particularly preferably contains a photopolymerization initiator. Among these, from the viewpoint of liquid storage stability of the recording liquid and the processing liquid, since the polymerization initiator is preferably independent of the polymerizable compound, the polymerization initiator is preferably contained in the processing liquid.

The polymerization initiator in the present invention is a compound that undergoes a chemical change through the action of light or the interaction with the electronically excited state of a sensitizing dye to generate at least one of radicals, acids, and bases. Among them, the photo radical generator or the photo acid generator is preferable from the viewpoint that polymerization can be initiated by a simple means of exposure.
As the photopolymerization initiator, those having sensitivity to ultraviolet rays irradiated at the time of low illumination exposure, for example, ultraviolet rays of 400 to 200 nm can be appropriately selected and used.

  Specific photopolymerization initiators known to those skilled in the art can be used without limitation, and specifically, for example, Bruce M. et al. Monroe et al., Chemical Review, 93, 435 (1993). R. S. By Davidson, Journal of Photochemistry and biologic A: Chemistry, 73.81 (1993). J. P. Faussier “Photoinitiated Polymerization—Theory and Applications”: Rapra Review vol. 9, Report, Rapra Technology (1998). M. Tsunooka et al. , Prog. Polym. Sci. , 21, 1 (1996). Many are described. There are many chemical amplification type photoresists and compounds used for photocationic polymerization described in (Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), pages 187-192). Has been. Further, F.I. D. Saeva, Topics in Current Chemistry, 156, 59 (1990). G. G. Maslak, Topics in Current Chemistry, 168, 1 (1993). H., et al. B. Shuster et al, JACS, 112, 6329 (1990). I. D. F. Eaton et al, JACS, 102, 3298 (1980). A group of compounds that undergo oxidative or reductive bond cleavage through interaction with the electronically excited state of a sensitizing dye as described in the above.

  Preferred photopolymerization initiators include (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, (e) ketoxime ester compounds, f) borate compounds, (g) azinium compounds, (h) metallocene compounds, (i) active ester compounds, (j) compounds having a carbon halogen bond, and the like.

  (A) As a preferable example of aromatic ketones, “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. Examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in RABEK (1993), p77-117. More preferable examples of (a) aromatic ketones include α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, and JP-B-47-22326. Α-substituted benzoin compounds, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, Benzoin ethers described in JP-A-60-26403, JP-A-62-81345, JP-B-1-34242, US Pat. No. 4,318,791, and α-aminobenzophenones described in European Patent 0284561A1, P-di (dimethyla) described in JP-A-2-211452 Nobenzoyl) benzene, thio-substituted aromatic ketone described in JP-A-61-194062, acylphosphine sulfide described in JP-B-2-9597, acylphosphine described in JP-B-2-9596, JP-B-63- Examples thereof include thioxanthones described in Japanese Patent No. 61950, and coumarins described in Japanese Patent Publication No. 59-42864.

  (B) Aromatic onium salts include Group V, VI and VII elements of the Periodic Table, specifically N, P, As, Sb, Bi, O, S, Se, Te, or I fragrances Group onium salts are included. For example, iodonium salts described in European Patent No. 104143, US Pat. No. 4,837,124, Japanese Patent Laid-Open No. 2-150848, Japanese Patent Laid-Open No. 2-96514, European Patent Nos. 370693, 233567, and 297443 are disclosed. , 294442, 279210, and 422570, U.S. Pat. Nos. 3,902,144, 4,933,377, 4,760013, 4,734,444, and 2,833,827, sulfonium salts and diazonium salts (Such as benzenediazonium which may have a substituent), diazonium salt resins (formaldehyde resin of diazodiphenylamine, etc.), N-alkoxypyridinium salts, etc. (for example, US Pat. No. 4,743,528, JP 63-1383 No. 5, JP-A-63-142345, JP-A-63-142346, and JP-B-46-42363, specifically 1-methoxy-4-phenylpyridinium tetrafluoro And the compounds described in JP-B Nos. 52-147277, 52-14278, and 52-14279 are preferably used. Generates radicals and acids as active species.

  (C) “Organic peroxide” includes almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. Examples thereof include 3,3 ′, 4,4′-tetra- (T-Butylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra- (t-amylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra- (t-hexylperoxycarbonyl) Benzophenone, 3,3′4,4′-tetra- (t-octylperoxycarbonyl) benzophenone, 3,3′4,4′-tetra- (cumylperoxycarbonyl) benzophenone, 3,3′4,4 ′ Peroxide esters such as tetra- (p-isopropylcumylperoxycarbonyl) benzophenone and di-t-butyldiperoxyisophthalate are preferred.

  (D) Examples of hexaarylbiimidazoles include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5. , 5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2, 2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′, 5,5 ′ -Tet Phenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′ , 5,5′-tetraphenylbiimidazole and the like.

  (E) As ketoxime esters, 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentane-3-one 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminobutan-2-one, 2-ethoxycarbonyloxy Examples include imino-1-phenylpropan-1-one.

Examples of the (f) borate salt which is another example of the photopolymerization initiator in the present invention include U.S. Pat. Nos. 3,567,453 and 4,343,891, European Patents 109,772 and 109,773. The compounds described in No. are listed.
Examples of (g) azinium salt compounds which are other examples of photopolymerization initiators include JP-A Nos. 63-138345, 63-142345, 63-142346, and 63-63. No. 143537 and Japanese Examined Patent Publication No. 46-42363.

Examples of (h) metallocene compounds which are other examples of photopolymerization initiators include JP 59-152396, JP 61-151197, JP 63-41484, and JP 2-249. And titanocene compounds described in JP-A-2-4705 and iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109.
Specific examples of the titanocene compound include di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, and di-cyclopentadienyl-Ti-bis-2,3. 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti- Bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4 -Difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti- -2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyridin-1-yl) phenyl) titanium, bis (cyclopentadienyl) bis [2,6-difluoro-3- (methylsulfonamido) phenyl] titanium, bis (cyclopenta And dienyl) bis [2,6-difluoro-3- (N-butylbialoyl-amino) phenyl] titanium.

  (I) Examples of the active ester compound include European Patent Nos. 0290750, 046083, 156153, 271851, and 0388343, U.S. Pat. Nos. 3,901,710, and 4,181,531, Nitrobenzol ester compounds described in JP-A-60-198538 and JP-A-53-133022, European Patents 0199672, 84515, 199672, 0441115, and 0101122 U.S. Pat. Nos. 4,618,564, 4,371,605, and 4,431,774, JP-A 64-18143, JP-A-2-245756, and JP-A-4-365048, respectively. 62-6223, Shoko 63 No. 14340, and include compounds described in JP-59-174831 each publication.

  (J) Preferred examples of the compound having a carbon halogen bond include those described in Wakabayashi et al., Bull. Chem. Soc. Examples include compounds described in Japan, 42, 2924 (1969), compounds described in British Patent 1388492, compounds described in JP-A-53-133428, compounds described in German Patent 3333724, and the like. .

  F.F. C. J. Schaefer et al. Org. Chem. 29, 1527 (1964), compounds described in JP-A-62-258241, compounds described in JP-A-5-281728, and the like. A compound as described in German Patent No. 2641100, a compound described in German Patent No. 3333450, a compound group described in German Patent No. 3021590, or a compound group described in German Patent No. 3021599, etc. Can be mentioned.

  Preferable specific examples of the compounds represented by the above (a) to (j) include those shown below.

A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.
Moreover, it is preferable that the mass concentration of a polymerization initiator is 0.1-8.0 mass%, More preferably, it is 1.0-7.0 mass%, More preferably, it is 2.0-6.0 mass%. It is.
When the polymerization initiator is contained only in the treatment liquid, a relatively low molecular weight polymerization initiator is preferred in order to increase the diffusibility of the polymerization initiator. As the polymerization initiator having a low molecular weight and excellent curability, TPO-L (Exemplary Compound-Initiator-1)), Irgacure 1870, DAROCUR TPO (manufactured by Ciba Special Chemicals) and the like are preferable.
When the polymerization initiator is contained only in the treatment liquid, the weight concentration of the polymerization initiator is preferably 1 to 20% by mass, more preferably 2.0 to 15.0% by mass, and still more preferably. Is 3.0-10.0 mass%.

(Sensitizing dye)
If necessary, a sensitizing dye may be added to the recording liquid and / or processing liquid in the present invention for the purpose of improving the sensitivity of the photopolymerization initiator. The sensitizing dye is preferably contained in the treatment liquid containing the photopolymerization initiator from the viewpoint of liquid stability.
Examples of preferred sensitizing dyes include those belonging to the following compounds and having an absorption wavelength in the 350 nm to 450 nm region.
Polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thiacarbocyanine, oxacarbocyanine), merocyanines ( For example, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), anthraquinones (eg, anthraquinone), squalium (eg, squalium) ), Coumarins (eg 7-diethylamino-4-methylcoumarin).

  More preferable examples of the sensitizing dye include compounds represented by the following general formulas (IX) to (XIII).

In formula (IX), A ¹ represents a sulfur atom or NR ⁵⁰ , R ⁵⁰ represents an alkyl group or an aryl group, and L ² forms a basic nucleus of the dye together with the adjacent A ¹ and the adjacent carbon atom. R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁵¹ and R ⁵² may be bonded to each other to form an acidic nucleus of the dye. Good. W represents an oxygen atom or a sulfur atom.
In formula (X), Ar ¹ and Ar ² each independently represent an aryl group and are linked via a bond with —L ³ —. Here, L ³ represents —O— or —S—. W is synonymous with that shown in the general formula (IX).
In the formula (XI), A ² represents a sulfur atom or NR ⁵⁹ , L ⁴ represents a nonmetallic atomic group that forms a basic nucleus of the dye together with the adjacent A ² and carbon atom, R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ and R ⁵⁸ each independently represents a monovalent nonmetallic atomic group, and R ⁵⁹ represents an alkyl group or an aryl group.

In formula (XII), A ³ and A ⁴ each independently represent —S— or —NR ⁶² — or —NR ⁶³ —, wherein R ⁶² and R ⁶³ each independently represent a substituted or unsubstituted alkyl group, substituted or represents an unsubstituted aryl group, L to ^5, L ⁶ are each independently, together with the adjacent a ^3, a ⁴ and adjacent carbon atoms represents a nonmetallic atom group necessary for forming a basic nucleus of a dye, R ⁶⁰ , R ⁶¹ each independently represents a hydrogen atom or a monovalent non-metallic atomic group, or may be bonded to each other to form an aliphatic or aromatic ring.
In formula (XIII), R ⁶⁶ represents an aromatic ring or a hetero ring which may have a substituent, and A ⁵ represents an oxygen atom, a sulfur atom or —NR ⁶⁷ —. R ⁶⁴ , R ⁶⁵ and R ⁶⁷ each independently represent a hydrogen atom or a monovalent nonmetallic atomic group, and R ⁶⁷ and R ⁶⁴ , and R ⁶⁵ and R ⁶⁷ each represent an aliphatic or aromatic ring. Can be combined to form.

  Preferred specific examples of the compounds represented by the general formulas (IX) to (XIII) include the exemplified compounds (A-1) to (A-20) shown below.

(Co-sensitizer)
Further, a known compound having an action such as further improving sensitivity or suppressing polymerization inhibition by oxygen may be added as a co-sensitizer to the recording liquid and / or processing liquid in the present invention. Like the sensitizing dye, the co-sensitizer is preferably contained in the treatment liquid containing the photopolymerization initiator from the viewpoint of liquid stability.
Examples of such cosensitizers include amines such as M.I. R. Sander et al., “Journal of Polymer Society”, Vol. 10, 3173 (1972), Japanese Patent Publication No. 44-20189, Japanese Patent Publication No. 51-82102, Japanese Patent Publication No. 52-134692, Japanese Patent Publication No. 59-138205. No. 60-84305, JP-A 62-18537, JP-A 64-33104, Research Disclosure 33825, and the like. Specific examples include triethanolamine. P-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline and the like.

Other examples include thiols and sulfides, for example, thiol compounds described in JP-A-53-702, JP-B-55-500806, JP-A-5-142772, and JP-A-56-75643. Examples thereof include disulfide compounds, and specific examples include 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-4 (3H) -quinazoline, β-mercaptonaphthalene and the like.
Other examples include amino acid compounds (eg, N-phenylglycine), organometallic compounds described in Japanese Patent Publication No. 48-42965 (eg, tributyltin acetate), and hydrogen described in Japanese Patent Publication No. 55-34414. Donors, sulfur compounds described in JP-A-6-308727 (eg, trithiane), phosphorus compounds described in JP-A-6-250387 (diethylphosphite, etc.), Si-- described in JP-A-8-65779 H, Ge-H compound, etc. are mentioned.

In the recording liquid and / or processing liquid in the present invention, in addition to the sensitizing dye and co-sensitizer used together with the polymerization initiator component and polymerization initiator component which are essential components and optional components, there are various types depending on the purpose. Additives can be used in combination. For example, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration. In addition, an antioxidant can be added to improve the stability of the recording liquid and / or the processing liquid.
The recording liquid and / or processing liquid in the present invention further includes various organic and metal complex anti-fading agents, potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride for the purpose of controlling ejection properties. In order to improve the adhesiveness with conductive salts such as salts and the recording medium, a trace amount of organic solvent can be added.

Various polymer compounds can be added to the recording liquid and / or the processing liquid in order to adjust the film properties. Examples of polymer compounds include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, vinyl resins, acrylic resins. Rubber resins, waxes and other natural resins can be used. Two or more of these may be used in combination.
In addition, nonionic surfactants, cationic surfactants, organic fluoro compounds, and the like can be added to adjust liquid properties. In addition, for example, leveling additives, matting agents, In order to improve the adhesion to the recording medium such as waxes for adjusting film physical properties, polyolefin, PET, etc., a tackifier that does not inhibit the polymerization can be contained.

(High boiling point organic solvent)
In the present invention, as described in the above “lipophilic solvent”, the recording liquid or the processing liquid may contain a high boiling point organic solvent. As described above, from the viewpoint of suppressing the emission of volatile organic compounds (VOC). The treatment liquid preferably contains a high boiling point organic solvent.
As the high boiling point organic solvent, (1) a viscosity at 25 ° C. of 100 mPa · s or less or a viscosity at 60 ° C. of 30 mPa · s or less and (2) a boiling point higher than 100 ° C. is preferable.

  In a high boiling point organic solvent that does not satisfy any of the viscosity conditions of (1), the viscosity becomes high, which may hinder application on a recording medium, and the boiling point condition of (2) is satisfied. If the organic solvent has a high boiling point, the boiling point becomes too low and the solvent evaporates during image recording, which may reduce the effect of the present invention.

  Among the conditions (1), the viscosity at 25 ° C. is further preferably in the range of 70 mPa · s or less, more preferably in the range of 40 mPa · s or less, and particularly preferably in the range of 20 mPa · s or less. The viscosity at 60 ° C. is more preferably in the range of 20 mPa · s or less, and particularly preferably in the range of 10 mPa · s or less. Regarding the condition (2), the boiling point is more preferably in the range of 150 ° C. or higher, and particularly preferably in the range of 170 ° C. or higher. Moreover, as a lower limit of melting | fusing point, the range of 80 degrees C or less is preferable. Furthermore, the solubility (25 ° C.) of water is preferably 4 g or less, more preferably 3 g or less, further preferably 2 g or less, and particularly preferably 1 g or less.

  The “viscosity” here is a viscosity determined using a RE80 viscometer manufactured by Toki Sangyo Co., Ltd. The RE80 type viscometer is a conical rotor / flat plate type viscometer corresponding to the E type, and the rotor code No. 1 rotor was used and the measurement was performed at a rotation speed of 10 rpm. However, for those having a viscosity higher than 60 mPa · s, the rotational speed is 5 r.p.m., 2.5 r.p.m., 1 r.p.m., 0.5 r.p.m. The measurement was performed by changing to.

  The “water solubility” is the saturation concentration of water in a high boiling point organic solvent at 25 ° C., and means the mass (g) of water that can be dissolved in 100 g of the high boiling point organic solvent at 25 ° C.

  As the high boiling organic solvent, compounds represented by the following formulas [S-1] to [S-9] are preferable.

In the formula [S-1], R ₁ , R ₂ and R ₃ each independently represents an aliphatic group or an aryl group. A, b and c each independently represent 0 or 1;

In the formula [S-2], R ₄ and R ₅ each independently represents an aliphatic group or an aryl group, and R ₆ represents a halogen atom (F, Cl, Br, I and so on), an alkyl group, an alkoxy group, Represents an aryloxy group, an alkoxycarbonyl group or an aryloxycarbonyl group, and d represents an integer of 0 to 3. When d is plural, plural R ₆ may be the same or different.

In the formula [S-3], Ar represents an aryl group, e represents an integer of 1 to 6, and R ₇ represents an e-valent hydrocarbon group or a hydrocarbon group bonded to each other through an ether bond.

In the formula [S-4], R ₈ represents an aliphatic group, f represents an integer of 1 to 6, and R ₉ represents an f-valent hydrocarbon group or a hydrocarbon group bonded to each other through an ether bond.

In the formula [S-5], g represents an integer of 2 to 6, R ₁₀ represents a g-valent hydrocarbon group (excluding an aryl group), and R ₁₁ represents an aliphatic group or an aryl group.

In the formula [S-6], R ₁₂ , R ₁₃ and R ₁₄ each independently represents a hydrogen atom, an aliphatic group or an aryl group. X represents —CO— or —SO ₂ —. R ₁₂ and R ₁₃ or R ₁₃ and R ₁₄ may be bonded to each other to form a ring.

In the formula [S-7], R ₁₅ represents an aliphatic group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an aryl group or a cyano group, and R ₁₆ represents a halogen atom, an aliphatic group or an aryl group. Represents a group, an alkoxy group or an aryloxy group, and h represents an integer of 0 to 3. When h is plural, plural R ₁₆ may be the same or different.

In the formula [S-8], R ₁₇ and R ₁₈ each independently represents an aliphatic group or an aryl group, R ₁₉ represents a halogen atom, an aliphatic group, an aryl group, an alkoxy group or an aryloxy group, and i Represents an integer of 0 to 5. When i is plural, plural R ₁₉ may be the same or different.

In the formula [S-9], R ₂₀ and R ₂₁ each independently represents an aliphatic group or an aryl group. j represents 1 or 2; R ₂₀ and R ₂₁ may be bonded to each other to form a ring.

In the formulas [S-1] to [S-9], when R _{1 to} R ₆ , R ₈ and R _{11 to} R ₂₁ are an aliphatic group or a group containing an aliphatic group, the aliphatic group is a straight chain, It may be branched or cyclic, and may contain an unsaturated bond or may have a substituent. Examples of the substituent include a halogen atom, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, a hydroxyl group, an acyloxy group, and an epoxy group.

In the formulas [S-1] to [S-9], R _{1 to} R ₆ , R ₈ and R _{11 to} R ₂₁ are cyclic aliphatic groups, that is, cycloalkyl groups, or groups containing cycloalkyl groups. Sometimes, the cycloalkyl group may contain an unsaturated bond in the 3- to 8-membered ring, and may have a substituent or a bridging group. Examples of the substituent include a halogen atom, an aliphatic group, a hydroxyl group, an acyl group, an aryl group, an alkoxy group, and an epoxy group, and examples of the crosslinking group include methylene, ethylene, isopropylidene, and the like.

In the formulas [S-1] to [S-9], when R _{1 to} R ₆ , R ₈ , R _{11 to} R ₂₁ , Ar is an aryl group or a group containing an aryl group, the aryl group is a halogen atom, aliphatic It may be substituted with a substituent such as a group, an aryl group, an alkoxy group, an aryloxy group, or an alkoxycarbonyl group.

In the formulas [S-3], [S-4], and [S-5], when R ₇ , R _9, or R ₁₀ is a hydrocarbon group, the hydrocarbon group is a cyclic structure (for example, a benzene ring, a cyclopentane ring, A cyclohexane ring) or an unsaturated bond, and may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an acyloxy group, an aryl group, an alkoxy group, an aryloxy group, and an epoxy group.

Hereinafter, among the high boiling point organic solvents represented by the formulas [S-1] to [S-9], particularly preferred high boiling point organic solvents will be described.
In the formula [S-1], R ₁ , R ₂ and R ₃ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, n-butyl, n-hexyl, n -Octyl, EH-octyl, 2-ethylhexyl, 3,3,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, n-octadecyl, benzyl, oleyl, 2-chloroethyl, 2,3-dichloro Propyl, 2-butoxyethyl, 2-phenoxyethyl, cyclopentyl, cyclohexyl, 4-t-butylcyclohexyl, 4-methylcyclohexyl) or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, Cresyl, p-nonylphenyl, xylyl, cumenyl, p-methoxyphenyl, p-methoxycarbonylphenyl) are preferred Yes. Among these, R ₁ , R ₂ and R ₃ are particularly n-hexyl, n-octyl, EH-octyl, 2-ethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, 2-chloroethyl, 2- Butoxyethyl, cyclohexyl, phenyl, cresyl, p-nonylphenyl and cumenyl are preferred.
a, b, and c are each independently 0 or 1, and more preferably, all of a, b, and c are 1.

In the formula [S-2], R ₄ and R ₅ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, the same group as the aliphatic group mentioned for R ₁ above). , Heptyl, ethoxycarbonylmethyl, 1,1-diethylpropyl, 2-ethyl-1-methylhexyl, cyclohexylmethyl, 1-ethyl-1,5-dimethylhexyl, 3,5,5-trimethylcyclohexyl, menthyl, bornyl, 1-methylcyclohexyl) or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for R ₁ , 4-t-butylphenyl, 4-t-octylphenyl, 1, 3,5-trimethylphenyl, 2,4, -di-t-butylphenyl, 2,4, -di-t-pentylphenyl) are preferred. Among these, R ₄ and R ₅ are more preferably aliphatic groups, and particularly preferably n-butyl, heptyl, 2-ethylhexyl, n-dodecyl, 2-butoxyethyl, and ethoxycarbonylmethyl.
R ₆ is a halogen atom (preferably a chlorine atom), an alkyl group having 1 to 18 carbon atoms (eg, methyl, isopropyl, t-butyl, n-dodecyl), an alkoxy group having 1 to 18 carbon atoms (eg, methoxy, n -Butoxy, n-octyloxy, methoxyethoxy, benzyloxy), an aryloxy group having 6 to 18 carbon atoms (for example, phenoxy, p-tolyloxy, 4-methoxyphenoxy, 4-t-butylphenoxy) or 2 carbon atoms A C-19 alkoxycarbonyl group (for example, methoxycarbonyl, n-butoxycarbonyl, 2-ethylhexyloxycarbonyl) or an aryloxycarbonyl group having 6 to 25 carbon atoms is preferred. Among these, R ₆ is further preferably an alkoxycarbonyl group, and particularly preferably n-butoxycarbonyl.
d is 0 or 1.

In the formula [S-3], Ar is an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, 4-chlorophenyl, 2,4-dichlorophenyl, 4-methoxyphenyl, 1-naphthyl, 4- n-butoxyphenyl, 1,3,5-trimethylphenyl, 2- (2-n-butoxycarbonylphenyl) phenyl) are preferable, and among these, Ar is phenyl, 2,4-dichlorophenyl, 2- (2 -N-Butoxycarbonylphenyl) phenyl is preferred.
e is an integer of 1 to 4 (preferably 1 to 3).
R ₇ is an e-valent hydrocarbon group having 2 to 24 (preferably 2 to 18) carbon atoms [for example, the aliphatic group mentioned above for R ₄ , n-octyl, the aryl group mentioned for R ₄ ,-( CH _{2) 2} -,

] Or an e-valent hydrocarbon group having 4 to 24 (preferably 4 to 18) carbon atoms and bonded to each other by an ether bond [for example, —CH ₂ CH ₂ OCH ₂ CH ₂ —, —CH ₂ CH ₂ (OCH _{2 CH 2) 3 -, - CH} 2 CH 2 CH 2 OCH 2 CH 2 CH 2 -,

] Is preferable. Among these, R ₇ is more preferably an alkyl group, and particularly preferably n-butyl, n-octyl and 2-ethylhexyl.

In the formula [S-4], R ₈ is an aliphatic group having 1 to 24 (preferably 1 to 17) carbon atoms (for example, methyl, n-propyl, 1-hydroxyethyl, 1-ethylpentyl, n-heptyl, n - undecyl, n- tridecyl, pentadecyl, 8,9-epoxy heptadecyl, cyclopropyl, cyclohexyl, 4-methylcyclohexyl). among them, R ₈ in particular, n- heptyl, n- tridecyl, 1-hydroxy Ethyl, 1-ethylpentyl, and 8,9-epoxyheptadecyl are preferred.
f is an integer of 1 to 4 (preferably 1 to 3).
R ₉ is a hydrocarbon group having 2 to 24 (preferably 2 to 18) f-valent carbon atoms or a hydrocarbon group linked to each other by an ether bond having 4 to 24 (preferably 4 to 18) f-valent carbon atoms. (For example, the groups mentioned for R ₇ , 1-methyl-2-methoxyethyl, 2-hexyldecyl) are preferable, and among these, R ₉ is particularly 2-ethylhexyl, 2-hexyldecyl, 1-methyl-2 -Methoxyethyl,

Is preferred.

In the formula [S-5], g is 2 to 4 (preferably 2 or 3).
R ₁₀ represents a g-valent hydrocarbon group [for example, —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₄ —, — (CH ₂ ) ₇ —, — (CH ₂ ) ₈ —,

Among these, R ₁₀ is particularly — (CH ₂ ) ₄ —, — (CH ₂ ) ₈ —,

Is preferred.
R ₁₁ is an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms, or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aliphatic groups mentioned for R ₄ above, Aryl group). Among these, R ₁₁ is more preferably an alkyl group, and n-butyl, n-octyl, and 2-ethylhexyl are particularly preferable.

In the formula [S-6], R ₁₂ is a hydrogen atom, an aliphatic group having 1 to 24 carbon atoms (preferably 3 to 20) [for example, n-propyl, 1-ethylpentyl, n-undecyl, n-pentadecyl, 2,4-di-t-pentylphenoxymethyl, 4-t-octylphenoxymethyl, 3- (2,4-di-t-butylphenoxy) propyl, 1- (2,4-di-t-butylphenoxy) propyl Cyclohexyl, 4-methylcyclohexyl, 8-N, N-diethylcarbamoyloctyl], or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for Ar, 3-methylphenyl) , 2-(N, N-di -n- octylcarbamoyl) phenyl). among them, R ₁₂ is especially, n- undecyl, 8-N, N-di Ji carbamoyl octyl, 3-methylphenyl, 2-(N, N-di -n- octylcarbamoyl) phenyl are preferred.
R ₁₃ and R ₁₄ are each a hydrogen atom or an aliphatic group having 1 to 24 (preferably 1 to 18) carbon atoms (eg, methyl, ethyl, isopropyl, n-butyl, n-hexyl, n-octyl, 2-ethylhexyl). , N-dodecyl, n-tetradecyl, cyclopentyl, cyclopropyl) or an aryl group having 6 to 18 carbon atoms (preferably 6 to 15) (for example, phenyl, 1-naphthyl, p-tolyl), among these, R ₁₃ and R ₁₄ are particularly preferably methyl, ethyl, n-butyl, n-octyl, n-tetradecyl and phenyl.
R ₁₃ and R ₁₄ may be bonded to each other to form a pyrrolidine ring, piperidine ring or morpholine ring together with N, and R ₁₂ and R ₁₃ may be bonded to each other to form a pyrrolidone ring or piperidine ring together with N. Also good.
X is —CO— or —SO ₂ —, and preferably X is —CO—.

In the formula [S-7], R ₁₅ is an aliphatic group having 1 to 24 (preferably 3 to 18) carbon atoms (for example, methyl, isopropyl, t-butyl, t-pentyl, t-hexyl, t-octyl, 2 -Butyl, 2-hexyl, 2-octyl, 2-dodecyl, 2-hexadecyl, t-pentadecyl, cyclopentyl, cyclohexyl), an alkoxycarbonyl group having 2 to 24 (preferably 5 to 17) carbon atoms (for example, n-butoxy) Carbonyl, 2-ethylhexyloxycarbonyl, n-dodecyloxycarbonyl), aryloxycarbonyl group having 7 to 24 carbon atoms (preferably 7 to 18) (for example, phenoxycarbonyl group, naphthoxycarbonyl group, cresyloxycarbonyl group) An alkylsulfonyl group having 1 to 24 (preferably 1 to 18) carbon atoms ( For example, methylsulfonyl, n-butylsulfonyl, n-dodecylsulfonyl), arylsulfonyl groups having 6 to 30 carbon atoms (preferably 6 to 24) (for example, p-tolylsulfonyl, p-dodecylphenylsulfonyl, p-hexadecyloxy) Phenylsulfonyl), an aryl group having 6 to 32 carbon atoms (preferably 6 to 24 carbon atoms) (for example, phenyl, p-tolyl), or a cyano group is preferable, and among these, R ₁₅ is further having 1 to 24 carbon atoms. An aliphatic group and an alkoxycarbonyl group having 2 to 24 carbon atoms are more preferable, and an aliphatic group having 1 to 24 carbon atoms is particularly preferable.
R ₁₆ is a halogen atom (preferably Cl), an aliphatic group having 1 to 24 carbon atoms (preferably 1 to 18 carbon atoms) {more preferably an alkyl group (for example, the alkyl groups mentioned for R ₁₅ above), carbon atoms 3-18 (more preferably 5-17) cycloalkyl group (for example, cyclopentyl, cyclohexyl)}, aryl group having 6-32 (preferably 6-24) carbon atoms (for example, phenyl, p-tolyl), carbon atom An alkoxy group of 1 to 24 (preferably 1 to 18) (for example, methoxy, n-butoxy, 2-ethylhexyloxy, benzyloxy, n-dodecyloxy, n-hexadecyloxy) or 6 to 32 carbon atoms (preferably Is an aryloxy group (for example, phenoxy, pt-butylphenoxy, pt-octylphenoxy, m-pen) Decylphenoxy, a p- dodecyloxy-phenoxy) Of these, R ₁₆ is further more preferably an aliphatic group having 1 to 24 carbon atoms, particularly preferably an aliphatic group having 1 to 12 carbon atoms.
h is an integer of 1-2.

In the formula [S-8], preferred examples of R ₁₇ and R ₁₈ are the same as the examples other than the hydrogen atom in R ₁₃ and R ₁₄ , and among these, R ₁₇ and R ₁₈ further have an aliphatic group. More preferred are n-butyl, n-octyl and n-dodecyl. However, R ₁₇ and R ₁₈ are not bonded to each other to form a ring.
Preferred examples of R ₁₉ are the same as R ₁₆ described above, and among these, R ₁₉ is more preferably an alkyl group and an alkoxy group, and particularly preferably n-octyl, methoxy, n-butoxy and n-octyloxy. .
i is an integer of 1-5.

In the formula [S-9], preferred examples of R ₂₀ and R ₂₁ are the same as those of R ₁ , R ₂ and R ₃ when they are not bonded to form a ring. Among these, R ₂₀ and R ₂₁ Is particularly preferably a substituted or unsubstituted aliphatic group having 1 to 24 carbon atoms.
R ₂₀ and R ₂₁ may be bonded to each other to form a ring, and the formed ring is preferably a 3- to 10-membered ring, particularly preferably a 5- to 7-membered ring.
j represents 1 or 2, and preferably j is 1.

Hereinafter, specific examples of high-boiling organic solvents (Exemplary Compounds S-1 to S-53) and viscosities of the respective high-boiling organic solvents (values measured by the above means in an environment at 25 ° C. and 60 ° C .; mPa · s) And the boiling point (° C.).
Here, the boiling point of the high-boiling organic solvent is a value converted from the boiling point during vacuum distillation to normal pressure. In the following specific examples, those having no boiling point are confirmed not to boil at 170 ° C., and those having no viscosity at 25 ° C. are solid at 25 ° C.

  Even if one kind of high-boiling organic solvent is used alone, two or more kinds [for example, tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di (2-ethylhexyl) sebacate, dibutyl phthalate and poly (Nt- Butylacrylamide)]] may be used in combination.

  Examples of other high boiling point organic solvents and / or methods for synthesizing these high boiling point organic solvents include, for example, U.S. Pat. Nos. 2,322,027, 2,533,514, and 2, 772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3,700,454, 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4,004 , 928, 4,080,209, 4,127,413, 4,193,802, 4,207,393, 4,220,711, No. 4,239,851, No. 4,278,757, No. 4,353,9 No. 9, No. 4,363,873, No. 4,430,421, No. 4,430,422, No. 4,464,464, No. 4,483,918, No. 4,540,657, 4,684,606, 4,728,599, 4,745,049, 4,935,321, 5,013,639 European Patent Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A, 309,160A, 509,311A No. 510,576A, East German Patent No. 147,009, No. 157,147, No. 159,573, No. 225,240A, British Patent No. 2,091,124A, etc. Description, JP-A-48-47335, 50 No. 26530, No. 51-25133, No. 51-26036, No. 51-27921, No. 51-27922, No. 51-149028, No. 52-46816, No. 53-1520, No. 53-1521 53-15127, 53-146622, 54-91325, 54-106228, 54-118246, 55-59464, 56-64333, 56-81836, 59-204041, 61-84641, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941, 63-94552, 64-945 9454, 64-68745, JP-A-1-101543, 1-102454, 2-792, and 2 No. 4239, No. 2-43541, No. 4-29237, No. 4-30165, No. 4-232946, No. 4-346338, and the like.

  In the present invention, a high boiling organic solvent having a boiling point higher than 100 ° C. is preferable, and a high boiling organic solvent having a boiling point higher than 170 ° C. is more preferable.

  The amount of the high-boiling organic solvent added in the treatment liquid is preferably in the range of 50% to 100% by weight, more preferably 70% to 100% by weight, more preferably 90% by weight with respect to the total weight of the liquid. % To 100% by mass is particularly preferable.

<Other ingredients>
In addition to the components described above, known additives can be used in combination according to the purpose.
~ Storage stabilizer ~
A storage stabilizer can be added to the recording liquid and the processing liquid (preferably recording liquid) according to the present invention for the purpose of suppressing undesirable polymerization during storage. The storage stabilizer is preferably used in combination with the polymerizable compound, and it is preferable to use a storage stabilizer that is soluble in the contained droplets, liquid, or other coexisting components.

  Storage stabilizers include quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, and the like. Specific examples include benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, hydroquinone monomethyl ether, hydroquinone monobutyl ether, and copper naphthenate. It is done.

  The addition amount of the storage stabilizer is preferably adjusted as appropriate based on the activity of the polymerization initiator, the polymerizability of the polymerizable compound, and the type of the storage stabilizer, but in terms of the balance between storage stability and curability, In terms of solid content in the liquid, 0.005 to 1% by mass is preferable, 0.01 to 0.5% by mass is more preferable, and 0.01 to 0.2% by mass is more preferable.

~ Conductive salts ~
Conductive salts are solid compounds that improve conductivity. In the present invention, it is preferable not to use it substantially because there is a great concern of precipitation during storage, but it is possible to increase the solubility of conductive salts or use a highly soluble liquid component. If it is good, an appropriate amount may be added.
Examples of the conductive salts include potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride and the like.

~solvent~
In the present invention, a solvent other than the high-boiling solvent described above can be used. The solvent can be used for the purpose of improving the polarity and viscosity of liquid (ink), surface tension, solubility and dispersibility of coloring materials, adjusting conductivity, and adjusting printing performance.
Note that the solvent is a water-insoluble liquid and does not contain an aqueous solvent because it is preferable in terms of recording a high-quality image with quick drying and uniform line width. The configuration used is desirable.

  A low boiling point organic solvent that is an organic solvent at 100 ° C. or lower is also exemplified, but there is a concern that the curability is affected, and it is desirable not to use the low boiling point organic solvent in consideration of environmental pollution. When used, it is preferable to use a highly safe solvent, and a highly safe solvent is a solvent having a high management concentration (an index indicated by the work environment evaluation criteria), preferably 100 ppm or more, More preferably, it is 200 ppm or more. Specific examples include alcohols, ketones, esters, ethers, hydrocarbons, and the like, and specific examples include methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran.

  Solvents can be used in combination other than one kind alone, but when water and / or a low-boiling organic solvent is used, the amount of both used is preferably 0 to 20% by mass in each solution. 10 mass% is still more preferable, and it is preferable not to contain substantially. When water is contained in the recording liquid and the processing liquid according to the present invention, the time stability such as non-uniformity with time, liquid turbidity due to dye precipitation, etc. This is not preferable in terms of drying when a recording medium is used. In addition, it does not contain substantially means accepting presence of an inevitable impurity.

~ Other additives ~
Furthermore, known additives such as polymers, surface tension adjusters, ultraviolet absorbers, antioxidants, anti-fading agents and pH adjusters can be used in combination.
Regarding the surface tension adjusting agent, ultraviolet absorber, antioxidant, anti-fading agent, and pH adjusting agent, known compounds may be appropriately selected and used. For example, JP-A-2001-181549 discloses a specific example. The additives described can be used.

In addition to the above, the recording liquid and the processing liquid according to the present invention can be separately contained in the recording liquid and the processing liquid according to the present invention. The set of compounds has a feature of rapidly forming aggregates or rapidly thickening the liquid, thereby more effectively suppressing coalescence between adjacent droplets. Can do.
Examples of the reaction of the set of compounds include an acid / base reaction, a hydrogen bonding reaction with a carboxylic acid / amide group-containing compound, a crosslinking reaction represented by boronic acid / diol, and a reaction by electrostatic interaction with a cation / anion. Etc.

≪Inkjet recording method≫
In the ink jet recording method of the present invention, the above ink set, that is, the recording liquid and the processing liquid are used, and the droplet (I) of 100 pl or less made of the recording liquid and the liquid droplet of 100 pl or less made of the processing liquid. (II) is ejected onto a recording medium by an inkjet recording head, and after the ejection, an image is formed by polymerizing and curing by low-illuminance exposure with an illuminance on the surface of the recording medium of 1000 mW / cm ² or less. Then, the vertical projection area S1 of the droplet (I) onto the recording medium, the vertical projection area S2 of the droplet (II), and the droplet (I) and the droplet ( II) The vertical projection area S3 of the overlapping portion is S1 <S2 and S1 = S3.

  In the present invention, as a liquid for forming an image, a recording liquid containing a colorant and a polymerizable compound and a treatment liquid substantially not containing a colorant are used, and a liquid of 100 pl or less comprising the recording liquid. Droplets (I) and droplets (II) of 100 pl or less made of the treatment liquid are ejected onto a recording medium by an ink jet recording head to form an image.

(Relationship between S1, S2, and S3)
In the present invention, the vertical projection area S1 of the droplet (I) onto the recording medium, the vertical projection area S2 of the droplet (II), and the overlap of the droplet (I) and the droplet (II) at the time of exposure The vertical projection area S3 of the part is S1 <S2 and S1 = S3. This condition is synonymous with the fact that the boundary line between the droplet (I) and the droplet (II) is completely surrounded by the droplet (II). Therefore, whether or not this condition is satisfied is whether the relationship between the boundary line between the droplet (I) and the droplet (II) and the droplet (II) is observed visually or by an optical microscope on the recording medium after exposure. Can be judged by.
Since the ink is solidified and fixed by exposure, the relationship between S1, S2, and S3 at the time of exposure is substantially equal to the relationship between S1, S2, and S3 after the exposure, and S1, S2, and S3 at the time of exposure are the same after the exposure. It can be evaluated by microscopic observation.

  The boundary line between the droplet (I) and the droplet (II) can be defined as follows. When the colorant is not included in the droplet (I), the contour of the droplet (I) or the droplet (II) is a part of the boundary line between the droplet (I) and the droplet (II). On the other hand, when the droplet (I) contains a colorant, the boundary between the colored portion and the non-colored portion due to the colorant is defined as a boundary line between the droplet (I) and the droplet (II).

The relationship between the above S1, S2, and S3 will be described with reference to the drawings. FIG. 1A is a cross-sectional view showing the state of the droplet (I) and the droplet (II) during exposure, and FIG. 1B is a vertical projection of each droplet in the state of FIG. In FIGS. 1A and 1B, both ends of each droplet are shown connected by wavy lines. Specifically, FIG. 1 (A) shows a cross-section of a state in which the droplet (I) is deposited on the droplet (II) after the droplet (II) is deposited and then exposed. 1B shows the vertical projection area S1 of the droplet (I), the vertical projection area S2 of the droplet (II), and the vertical projection area of the overlapping portion of the droplet (I) and the droplet (II). S3 is shown. In FIG. 1, the vertical projection area S1 of the droplet (I) is smaller than the vertical projection area S2 of the droplet (II), and S1 is included in S2, that is, S1 <S2 and S1 = S3 It is. In other words, the boundary line between the droplet (I) and the droplet (II) is completely surrounded by the droplet (II).
With the above-described configuration, oxygen (such as radical polymerization type ink) and moisture (cations) generated in a low-density portion (an image formed by an ink droplet that does not overlap with an adjacent ink droplet), in particular. It is possible to reduce curing failure due to polymerization inhibition due to polymerization type inks and the like.

In the ink jet recording method of the present invention, the aforementioned droplet (I) and droplet (II) can be ejected using an ink jet recording head. This ink jet recording head will be described in the ink jet recording apparatus of the present invention described later.
In order to satisfy the relationship of S1, S2, and S3, an image in which droplet (II) is formed in advance by droplet (I) on a recording medium before droplet (I) is applied. It is preferable to apply to the same area or a wider area than the image. Furthermore, in order to satisfy the relationship of S1, S2, and S3, the droplet size of the droplet (I) is preferably smaller than the droplet size of the droplet (II), and the droplet of the droplet (I) As a balance between the size and the droplet size of the droplet (II), the applied amount (mass ratio) of the droplet (II) when the amount of the droplet (I) is 1 is preferably in the range of 1 to 5. The range of 1-3 is more preferable, and the range of 1-2 is especially preferable.

Next, an ejection method (inkjet recording method) by the ink jet recording head will be described.
In the present invention, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electric signal is converted into an acoustic beam into ink. Known systems such as an acoustic ink jet system that irradiates and discharges ink using radiation pressure, and a thermal ink jet (bubble jet (registered trademark)) system that uses ink to form bubbles by heating ink and generate pressure Is preferred.
Inkjet recording methods include a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different densities, and colorless and transparent inks. The method using is included.

In the present invention, after the treatment liquid and the recording liquid are deposited as described above, a step of fixing the recorded image by exposure is provided from the viewpoint of obtaining excellent fixability. By exposure, the curing reaction by polymerization or cross-linking of the polymerizable or cross-linkable material contained can be promoted, and a stronger image can be formed more efficiently. For example, in a system containing a polymerization initiator, generation of active species due to decomposition of the polymerization initiator is promoted by exposure, and polymerization of a polymerizable or crosslinkable material caused by the active species is caused by an increase in active species or a temperature rise. Curing reaction by crosslinking is promoted. In the present invention, low illuminance exposure is employed in which the illuminance on the surface of the recording medium is 1000 mW / cm ² or less. Next, the light source will be described.

(light source)
The low illuminance exposure in the inkjet recording method of the present invention is such that the illuminance between the wavelength region of 220 nm and 400 nm on the surface of the recording medium is 1000 mW / cm ² or less, from the viewpoint of reducing the amount of heat during exposure, preferably該照degree or less 800 mW / cm ^2, further preferably 500 mW / cm ² or less. (In addition, the spectroradiometer URS-40D made by USHIO ELECTRIC CO., LTD. Can be used for illuminance measurement, and a value obtained by integrating the wavelength between 220 nm and 400 nm can be used.)
The exposure energy accumulated amount due to the low illumination intensity exposure in the present invention, from the viewpoint of improving the printing speed, is preferably 30 mJ / cm ² or less, particularly preferably 30 mJ / cm ² or less.

  As a low illuminance light source for performing low illuminance exposure, it is preferable to use an LED that is relatively easily available and easy to handle. The LED preferably has an emission wavelength of 400 nm or less. Since the light emitting characteristics of the LED element are excellent in wavelength selectivity compared to a xenon lamp or the like, it is only necessary to select a wavelength that acts only on the photopolymerizable polymer or photopolymerization initiator contained in the ink. By using, decomposition, modification, etc. of other components (for example, colorants such as dyes and pigments) not involved in polymerization in the ink composition can be minimized. As such an LED element, for example, an ultraviolet LED manufactured by Nitride Semiconductor can be suitably used.

  The time until exposure after the droplets (I) and (II) are deposited is preferably 0.1 to 10 seconds, more preferably 0.1 to 5 seconds, 0 .1 to 2 seconds is particularly preferable.

<Recording medium>
As the recording medium, a non-permeable or slowly permeable recording medium is used.
Examples of the non-permeable recording medium include synthetic resin, rubber, resin-coated paper, glass, metal, earthenware, and wood. In addition, for the purpose of adding a function, a base material obtained by combining a plurality of these materials can be used.

Here, the non-permeable recording medium refers to a medium in which droplets do not substantially permeate. “Substantially does not penetrate” means that the penetration rate of a droplet after 1 minute is 5% or less. Further, the slow penetrable recording medium refers to a medium in which when a 10 pl (picoliter) droplet is dropped on a recording medium, the time until the entire liquid amount permeates is 100 milliseconds or more. Examples include art paper. Details of the non-permeable or slowly permeable recording medium will be described later.
Note that the permeable recording medium is a medium in which the time until the total liquid amount penetrates when a 10 pl droplet is dropped on the recording medium is 100 ms or less, specifically, plain paper, porous For example, quality paper.

  As the synthetic resin, any synthetic resin can be used. For example, polyesters such as polyethylene terephthalate and polybutadiene terephthalate, polyolefins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene, acrylic resins, polycarbonates, and acrylonitrile-butadiene. -Styrene copolymer etc., Diacetate, Triacetate, Polyimide, Cellophane, Celluloid etc. are mentioned. When the synthetic resin is used, the thickness and shape may be any of a film shape, a card shape, and a block shape, and are not particularly limited, and may be either transparent or opaque.

  The synthetic resin is preferably used in the form of a film used for so-called soft packaging, and various non-absorbable plastics and films thereof can be used. Examples of the plastic film include a PET film, an OPS film, an OPP film, a PNy film, a PVC film, a PE film, and a TAC film. Other plastics that can be used include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers.

  Examples of the resin-coated paper include a transparent polyester film, an opaque polyester film, an opaque polyolefin resin film, and a paper support in which both sides of paper are laminated with a polyolefin resin. Particularly preferred is a paper support in which both sides of the paper are laminated with a polyolefin resin.

  There is no restriction | limiting in particular as said metal, For example, aluminum, iron, gold | metal | money, silver, copper, nickel, titanium, chromium, molybdenum, silicon | silicone, lead, zinc etc., or stainless steel etc., and these composite materials are suitable. .

  Further, a read-only optical disk such as a CD-ROM or DVD-ROM, a write-once optical disk such as a CD-R or DVD-R, a rewritable optical disk, or the like can also be used. And a gloss-imparting layer.

<Inkjet recording apparatus>
The ink jet recording apparatus of the present invention is an ink jet recording apparatus using the above-described ink jet recording method of the present invention, and includes a recording liquid containing at least a colorant and a polymerizable compound, and a treatment liquid containing substantially no colorant. And a droplet (I) of 100 pl or less composed of the recording liquid and a droplet (II) of 100 pl or less composed of the treatment liquid are ejected onto a recording medium by an ink jet recording head, and after the ejection An inkjet recording apparatus that forms an image by polymerization and curing by low-illuminance exposure with a illuminance of 1000 mW / cm ² or less on the surface of the recording medium, wherein the droplet (I) is recorded on the recording medium at the time of low-illuminance exposure Vertical projection area S 1, vertical projection area S 2 of the droplet (II), and overlap of the droplet (I) and the droplet (II) Vertical projection area S3 parts is, S1 <S2, and wherein the discharging so that S1 = S3.

Next, a preferred embodiment of the ink jet recording apparatus of the present invention will be described with reference to FIGS. FIG. 2 is an overall configuration diagram of an example of the ink jet recording apparatus 10. The inkjet recording apparatus 10 applies at least two types of liquids, that is, a recording liquid containing at least a colorant and a polymerizable compound, and a treatment liquid substantially not containing a colorant to a recording medium 16 to obtain a desired image. Are formed on the recording medium 16.
In FIG. 2, the ink jet recording apparatus 10 includes a liquid applying unit 12 that applies a recording liquid and a processing liquid to a recording medium 16 by droplet ejection.

  The ink jet recording apparatus 10 also includes a liquid storage / loading unit 14 that stores recording liquid and processing liquid supplied to the liquid applying unit 12, a paper feeding unit 18 that supplies the recording medium 16, and a curl of the recording medium 16. The decurling unit 20 that removes the ink, the belt conveying unit 22 that is disposed to face the ejection surface of the liquid applying unit 12, and conveys the recording medium 16 while maintaining the flatness of the recording medium 16, and the liquid applying unit 12 An image detection unit 24 that reads an image as a result of ink droplet ejection (in an ink droplet landing state) and a paper discharge unit 26 that discharges a recorded recording medium to the outside are provided.

  In FIG. 2, as an example of the paper supply unit 18, one that feeds roll paper (continuous paper) is shown, but one that feeds cut paper that has been cut in advance may be used. In the case of an apparatus configuration that uses roll paper, a cutter 28 is provided. Incidentally, the recording medium 16 delivered from the paper supply unit 18 generally retains curl and curls. In order to remove the curl, heat is applied to the recording medium 16 by the heating drum 30 in the direction opposite to the curl direction in the decurling unit 20. After the decurling process, the cut recording medium 16 is sent to the belt conveyance unit 22.

  The belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and a portion facing the ejection surface of the liquid application unit 12 and the sensor surface of the image detection unit 24 is flat (flat). Surface). The belt 33 has a width that is wider than the width of the recording medium 16, and a plurality of suction holes (not shown) are formed on the belt surface. An adsorption chamber 34 is provided at a position facing the ejection surface of the liquid application unit 12 and the sensor surface of the image detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. The recording medium 16 on the belt is sucked and held by sucking with the fan 35 to be a negative pressure. The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, whereby the belt 33 is driven in the counterclockwise direction in FIG. The recording medium 16 is conveyed from right to left in FIG. Note that when a borderless print or the like is formed, the ink also adheres to the belt 33, so the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the recording area). In this embodiment, an example of holding the recording medium by negative pressure as an example of holding and conveying the recording medium has been described. However, other holding and conveying means (electrostatic adsorption conveyance, roller conveyance, etc.) are selectively used. You can also.

FIG. 3 is a plan view showing the liquid application unit 12 and its peripheral portion of the inkjet recording apparatus 10.
In FIG. 3, the liquid application unit 12 includes a droplet ejection head 12 </ b> P for treating liquid that ejects the treatment liquid onto the recording medium 16 in a single pass, and a recording liquid ejector that ejects the recording liquid onto the recording medium 16 in a single pass. The droplet ejection heads 12Y, 12M, 12C, and 12K. Specifically, a line-type head having a length corresponding to the entire recordable width of the recording medium 16 is perpendicular to the medium conveyance direction (the sub-scanning direction indicated by arrow S in FIG. 3) (main scanning direction). This is a so-called full-line type head.

Each of the droplet ejection heads 12P, 12Y, 12C, 12M, and 12K in this example has a plurality of nozzles (liquid ejection ports) over a length that exceeds at least one side of the maximum-size recording medium 16 targeted by the inkjet recording apparatus 10. It is arranged.
Further, along the medium transport direction S, from the upstream side (the right side in FIG. 3), the processing liquid (P), the yellow recording liquid (Y), the cyan recording liquid (C), and the magenta recording liquid ( M) and black recording liquid (K) are arranged in the order of droplet ejection heads 12P, 12Y, 12C, 12M, and 12K corresponding to the liquids, and a color image can be formed on the recording medium 16.

  Specifically, first, a treatment liquid droplet (II) is applied onto the recording medium 16 by the treatment liquid being ejected from the treatment liquid droplet ejection head 12P toward the recording medium 16, and this droplet is applied. Next, the recording liquid droplet (I) is ejected from the recording liquid droplet ejection heads 12Y, 12M, 12C, and 12K toward the recording medium 16 so as to overlap the region to which (II) is applied.

  Further, according to the liquid application unit 12 including a full-line type droplet ejection head, the operation of relatively moving the recording medium 16 and the liquid application unit 12 in the medium conveyance direction (sub-scanning direction) is performed only once. An image can be recorded on the entire surface of the recording medium 16. Thereby, high-speed printing is possible and productivity can be improved as compared with a shuttle type head in which the droplet ejection head reciprocates in a direction (main scanning direction) orthogonal to the medium conveyance direction.

The main scanning direction and the sub scanning direction are used in the following meaning. That is, when driving nozzles with a full line head having a nozzle row corresponding to the entire width of the recording medium, (1) whether all nozzles are driven simultaneously, or (2) whether the nozzles are driven sequentially from one side to the other (3) The nozzles are divided into blocks, and one of the nozzles is driven sequentially from one side to the other for each block, and the width direction of the recording medium (the conveying direction of the recording medium) Driving a nozzle that prints one line (a line made up of one row of dots or a line made up of a plurality of rows of dots) in an orthogonal direction is defined as main scanning. A direction indicated by one line (longitudinal direction of the belt-like region) recorded by the main scanning is called a main scanning direction.
On the other hand, by relatively moving the above-described full line head and the recording medium, printing of one line (a line composed of one line of dots or a line composed of a plurality of lines) formed by the above-described main scanning is repeatedly performed. Is defined as sub-scanning. A direction in which sub-scanning is performed is referred to as a sub-scanning direction. After all, the conveyance direction of the recording medium is the sub-scanning direction, and the direction orthogonal to it is the main scanning direction.

  In this embodiment, the configuration of the standard colors (4 colors) of YMCK is exemplified. However, the number of colors of the recording liquid and the combination of colors are not limited to the examples shown in this embodiment, and if necessary, Light ink, dark ink, white or other special color ink may be added. For example, a configuration in which a droplet ejection head that discharges a light recording liquid such as light cyan or light magenta is added, a configuration in which a background is drawn with white ink, or a glossiness adjustment with a transparent ink is possible.

The UV light source 27 irradiates the recording medium 16 with ultraviolet rays to cure the ink containing the polymerizable compound, and performs low-illuminance exposure with an illuminance of 1000 mW / cm ² or less. As the UV light source 27, it is preferable to use an LED. For example, an ultraviolet LED manufactured by Nitride Semiconductor can be suitably used. Although omitted in FIG. 2, in the case of ink containing a radical polymerizable compound, the ink is cured and fixed better by replacing the curing atmosphere of the UV irradiation part with an inert gas (such as nitrogen). be able to.

  The liquid storage / loading unit 14 shown in FIG. 2 has a processing liquid tank for storing a processing liquid and a liquid tank for storing ink for each color of YMCK, and each droplet ejection head 12P via a pipe line (not shown). , 12Y, 12C, 12M, and 12K.

  The image detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the liquid application unit 12, and as means for checking nozzle clogging and other ejection abnormalities from an image read by the image sensor. Function.

  The recording medium 16 as a printed matter on which an image is formed is discharged from the paper discharge unit 26. The ink jet recording apparatus 10 is provided with a selecting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharging portions 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by the cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when a test print is performed on an image margin. Although not shown, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

[Structure of droplet ejection head]
FIG. 4A shows a basic overall structure of the droplet ejection head 50 by adding a reference numeral 50 to the droplet ejection head representing the droplet ejection heads 12P, 12Y, 12C, 12M, and 12K shown in FIG. It is a plane perspective view which shows an example.

  The droplet ejection head 50 shown as an example in FIG. 4A is a so-called full-line head, and is in a direction (in the drawing) orthogonal to the conveyance direction of the recording medium 16 (in the sub-scanning direction indicated by arrow S in the drawing). A number of nozzles 51 (liquid ejection ports) that eject liquid toward the recording medium 16 are two-dimensionally arranged over a length corresponding to the width Wm of the recording medium 16 in the main scanning direction indicated by the arrow M). It has a structure.

The droplet ejection head 50 includes a nozzle 51, a pressure chamber 52 communicating with the nozzle 51, and a plurality of pressure chamber units 54 including a liquid supply port 53 in a predetermined manner with respect to the main scanning direction M and the main scanning direction M. They are arranged along two oblique directions forming an acute angle θ (0 degree <θ <90 degrees). In FIG. 4A, only a part of the pressure chamber units 54 is shown for convenience of illustration.
Specifically, the nozzles 51 are arranged at a constant pitch d in an oblique direction that forms a predetermined acute angle θ with respect to the main scanning direction M, and thus, “on a straight line along the main scanning direction M” d × cos θ ”can be handled equivalently.

FIG. 4B shows a cross-sectional view taken along the line bb in FIG. 4A with respect to the pressure chamber unit 54 described above as one ejection element constituting the droplet ejection head 50.
As shown in FIG. 4B, each pressure chamber 52 communicates with a common liquid chamber 55 via a liquid supply port 53. The common liquid chamber 55 communicates with a tank which is a liquid supply source (not shown), and the liquid supplied from the tank is distributed and supplied to each pressure chamber 52 via the common liquid chamber 55.

  A piezoelectric body 58a is disposed on the diaphragm 56 constituting the top surface of the pressure chamber 52, and an individual electrode 57 is disposed on the piezoelectric body 58a. The diaphragm 56 is grounded and functions as a common electrode. These diaphragm 56, individual electrode 57 and piezoelectric body 58a constitute a piezoelectric actuator 58 as means for generating a liquid ejection force.

  When a predetermined drive voltage is applied to the individual electrode 57 of the piezoelectric actuator 58, the piezoelectric body 58a is deformed to change the volume of the pressure chamber 52, and the pressure in the pressure chamber 52 is changed accordingly. Liquid is discharged. After the liquid is discharged, when the volume of the pressure chamber 52 is restored, a new liquid is supplied from the common liquid chamber 55 through the liquid supply port 53 to the pressure chamber 52.

  FIG. 4A shows an example in which a plurality of nozzles 51 are two-dimensionally arranged as a structure capable of forming a high-resolution image on the recording medium 16 at a high speed. The droplet head is not particularly limited to a structure in which a plurality of nozzles 51 are two-dimensionally arranged, and may have a structure in which a plurality of nozzles 51 are one-dimensionally arranged. The pressure chamber unit 54 shown in FIG. 4B as an ejection element constituting the droplet ejection head is an example, and is not particularly limited to such a case. For example, instead of disposing the common liquid chamber 55 below the pressure chamber 52 (that is, the discharge surface 510 side than the pressure chamber 52), the common liquid is disposed above the pressure chamber 52 (that is, opposite to the discharge surface 510). The chamber 55 may be disposed. Further, for example, instead of using the piezoelectric body 58a, a liquid discharge force may be generated using a heating element.

In the present invention, as means for applying the treatment liquid onto the recording medium, other means such as coating may be used in addition to the means for discharging the treatment liquid from the nozzle.
There is no restriction | limiting in particular as an apparatus used for the said application | coating, A well-known coating apparatus can be suitably selected according to the objective. Examples include air doctor coaters, blade coaters, lot coaters, knife coaters, squeeze coaters, impregnation coaters, reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, extrusion coaters, etc. It is done.

[Description of liquid supply system]
FIG. 5 is a schematic diagram showing the configuration of the liquid supply system in the inkjet recording apparatus 10.
The liquid tank 60 is a base tank for supplying liquid to the droplet ejection head 50. A liquid supply pump 62 that feeds liquid from the liquid tank 60 to the droplet ejection head 50 is provided in the middle of a pipe line that connects the liquid tank 60 and the droplet ejection head 50. It is preferable that the temperature of the liquid tank 60 and the droplet ejection head 50 and the pipe connecting the both are adjusted together with the ink inside by the temperature detection means and the heater. The ink temperature at this time is preferably adjusted to 40 ° C to 80 ° C.

Further, the inkjet recording apparatus 10 includes a cap 64 as a means for preventing the meniscus from drying of the nozzle 51 during the long discharge pause period or preventing a rise in viscosity near the meniscus, and a cleaning as a means for cleaning the discharge surface 50a. A blade 66 is provided.
The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the droplet ejection head 50 by a moving mechanism (not shown), and can be moved from a predetermined retraction position to a position below the droplet ejection head 50 as necessary. It is moved to the maintenance position.
Further, the cap 64 is moved up and down relatively with respect to the droplet ejection head 50 by a lifting mechanism (not shown). The elevating mechanism raises the cap 64 to a predetermined ascending position and contacts the droplet ejection head 50 to cover at least the nozzle region of the ejection surface 50a with the cap 64.
Preferably, the inside of the cap 64 is divided into a plurality of areas corresponding to the nozzle rows by a partition wall, and each of the partitioned areas can be selectively sucked by a selector or the like.

  The cleaning blade 66 is made of an elastic member such as rubber, and can slide on the ejection surface 50a of the droplet ejection head 50 by a cleaning blade moving mechanism (not shown). When droplets or foreign matter adhere to the discharge surface 50a, the discharge surface 50a is wiped by sliding the cleaning blade 66 on the discharge surface 50a, and the discharge surface 50a is cleaned.

The suction pump 67 sucks the liquid from the nozzle 51 of the droplet ejection head 50 in a state where the discharge surface 50 a of the droplet ejection head 50 is covered with the cap 64, and sends the sucked liquid to the recovery tank 68.
Such a suction operation is stopped for a long time, when the liquid tank 60 is loaded in the ink jet recording apparatus 10 and liquid is filled from the liquid tank 60 to the droplet ejection head 50 (at the time of initial filling), and the viscosity is increased by stopping for a long time. It is also performed when removing the liquid (when starting to use for a long time).

  Here, when the discharge from the nozzle 51 is arranged, firstly, there is normal discharge performed toward the recording medium in order to form an image on the recording medium such as paper, and secondly, the cap 64 is liquid. There is a purge (also referred to as idle discharge) performed toward the cap 64 as a receptacle.

  Further, if bubbles are mixed in the nozzle 51 or the pressure chamber 52 of the droplet ejection head 50 or if the viscosity increase in the nozzle 51 exceeds a certain level, the liquid cannot be discharged from the nozzle 51 by the above-described empty discharge. An operation in which the cap 64 is applied to the ejection surface 50 a of the droplet ejection head 50 and the liquid in which the bubbles in the pressure chamber 52 of the droplet ejection head 50 are mixed or the liquid having increased viscosity is sucked by the suction pump 67.

  Here, the liquid tank 60, the droplet ejection head 50, the liquid supply pump 62, the cap 64, the cleaning blade 66, the suction pump 67, the recovery tank 68, the ink flow path connecting them, and other members and devices that are in direct contact with ink are: It preferably has resistance to dissolution and swelling. Moreover, it is preferable that these members and equipment have light shielding properties.

[Description of control system]
FIG. 6 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10.
6, the ink jet recording apparatus 10 mainly includes a liquid application unit 12, an image detection unit 24, a UV light source 27, a communication interface 110, a system controller 112, memories 114 and 152, a transport motor 116, a motor driver 118, and a heater. 122, heater driver 124, medium type detection unit 132, ink type detection unit 134, illuminance detection unit 135, environmental temperature detection unit 136, environmental humidity detection unit 137, medium temperature detection unit 138, liquid supply unit 142, liquid supply driver 144 , A print control unit 150, a head driver 154, and a light source driver 156.
Since the liquid application unit 12, the image detection unit 24, and the UV light source 27 are the same as those described in FIG. 2 and have already been described, description thereof will be omitted here.

  The communication interface 110 is an image data input unit that receives image data transmitted from the host computer 300. As the communication interface 110, a wired or wireless interface such as USB (Universal Serial Bus) or IEEE1394 can be applied. The image data input to the inkjet recording apparatus 10 via the communication interface 110 is temporarily stored in the first memory 114 for storing image data.

  The system controller 112 includes a central processing unit (CPU) and its peripheral circuits, and is a main control unit that controls the entire inkjet recording apparatus 10 according to a predetermined program stored in the first memory 114 in advance. That is, the system controller 112 controls each unit such as the communication interface 110, the motor driver 118, the heater driver 124, the medium type detection unit 132, the ink type detection unit 134, and the print control unit 150.

  A conveyance motor 116 applies power to a roller, a belt, or the like for conveying a recording medium such as paper. By this transport motor 116, the droplet ejection head 50 and the recording medium constituting the liquid applying unit 12 are relatively moved. The motor driver 118 is a circuit that drives the conveyance motor 116 in accordance with an instruction from the system controller 112.

  The heater 122 is a circuit that drives the heating drum 30 and other heaters 122 in FIG. The heater driver 124 is a circuit that drives the heater 122 in accordance with an instruction from the system controller 112.

  The medium type detection unit 132 detects the type of the recording medium. There are various detection modes for the type of recording medium. For example, an aspect in which a sensor is provided in the paper feeding unit 18 in FIG. 2, an aspect in which the sensor is input by a user operation, an aspect in which the image is input from the host computer 300, and an image input from the host computer 300 There is a mode in which data (for example, resolution and color) or additional data of the image data is automatically detected by analyzing the data.

  The ink type detection unit 134 detects the type of ink. There are various types of ink type detection modes. For example, a mode in which a sensor is provided in the liquid storage / loading unit 14 in FIG. 2, a mode in which the liquid is input by a user operation, a mode in which the liquid is input from the host computer 300, and a mode in which the data is input from the host computer 300 There is a mode in which image data (for example, resolution and color) or additional data of the image data is automatically detected by analysis.

  The illuminance detection unit 135 detects the illuminance of ultraviolet rays emitted from the UV light source 27. As an illuminance detection mode, for example, an illuminance sensor is provided in the vicinity of the UV light source 27 in FIG.

The environmental temperature detector 136 detects the temperature of the outside air or the ink jet recording apparatus. As an environmental temperature detection mode, for example, there is a mode of detection by providing a temperature sensor outside or inside the device.
The environmental humidity detector 137 detects the outside air or humidity in the ink jet recording apparatus. As an environmental humidity detection mode, for example, there is a mode of detection by providing a humidity sensor outside or inside the device.

  The medium temperature detection unit 138 detects the temperature at the time of image formation on the recording medium. There are various medium temperature detection modes. For example, there are a mode in which a contact-type temperature sensor is provided in the belt conveyance unit 22 of FIG.

The liquid supply unit 142 includes a conduit for flowing ink from the liquid tank 60 to the liquid applying unit 12 in FIG.
The liquid supply driver 144 is a circuit that drives the liquid supply pump 62 and the like constituting the liquid supply unit 142 so that the liquid is supplied to the liquid application unit 12.

  Based on the image data input to the inkjet recording apparatus 10, the print control unit 150 is data necessary for each droplet ejection head 50 constituting the liquid application unit 12 to eject (droplet ejection) toward the recording medium. (Droplet ejection data) is generated. That is, the print control unit 150 functions as an image processing unit that performs image processing such as various processes and corrections for generating droplet ejection data from image data in the first memory 114 according to the control of the system controller 112. The generated droplet ejection data is supplied to the head driver 154.

The print controller 150 also determines the thickness of the liquid film formed on the recording medium by the processing liquid based on the medium type detected by the medium type detector 132 and the ink type detected by the ink type detector 134. And the thickness of the liquid film is switched by controlling the droplet ejection amount of the processing liquid using the head driver 154.
The print controller 150 is accompanied by a second memory 152, and droplet ejection data and the like are temporarily stored in the second memory 152 during image processing in the print controller 150.
In FIG. 6, the second memory 152 is shown in a form associated with the print control unit 150, but it can also be used as the first memory 114. Also possible is an aspect in which the print controller 150 and the system controller 112 are integrated and configured with one processor.

  The head driver 154 applies the droplet ejection data provided from the print control unit 150 (actually, the droplet ejection data stored in the second memory 152) to each droplet ejection head 50 constituting the liquid application unit 12. On the other hand, an ejection drive signal is output. The ejection drive signal output from the head driver 154 is applied to each droplet ejection head 50 (specifically, the actuator 58 shown in FIG. 4B), so that the liquid is ejected from the droplet ejection head 50 toward the recording medium. (Droplet) is discharged.

  The light source driver 156 detects an instruction from the print control unit 150, the illuminance detected by the illuminance detection unit 135, the environmental temperature detected by the environmental temperature detection unit 136, the environmental humidity detected by the environmental humidity detection unit 137, and the medium temperature detection. This is a circuit that controls the voltage, time, and timing input to the UV light source 27 based on the medium temperature detected by the unit 138 and drives the UV light source 27.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited to these.

[Preparation of pigment dispersion A]
Components having the following composition were mixed and stirred with a stirrer for 1 hour. The mixture after stirring was dispersed with an Eiger mill to obtain pigment dispersion A. Here, dispersion conditions were such that zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 1 hour.
(Composition of pigment dispersion A)
Monomer 1 (OXT221 (manufactured by Toagosei Co., Ltd.)) ... 60 parts by mass of cyan pigment A (PB15: 3 (IRGALITE BLUE GLO; manufactured by Ciba Specialty Chemicals)) ... 20 parts by mass of pigment dispersant A (BYK-168 (Bic Chemie) 20 parts by mass)

(Preparation of recording liquid and processing liquid)
Next, the components shown in Table 1 below were mixed by stirring and dissolved to prepare a recording liquid and a processing liquid. The surface tension was measured using a surface tension meter (CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.).

Monomer 2: Celoxide 3000 (manufactured by Daicel Chemical Industries)
Initiator A: Irgacure 250 (Ciba Specialty Chemicals)
Sensitizer A: Dibutoxyanthracene surfactant A: Fluorosurfactant (manufactured by Dainippon Ink & Chemicals, Megafac F475)

(Preparation of ink set)
The prepared recording liquid (1) and the treatment liquids (1) and (2) were combined to prepare ink sets shown in Table 2 in each example and comparative example. However, in Comparative Examples 1, 2, and 4, only the recording liquid was used without using the processing liquid.

(Printing)
The prepared ink set (recording liquid (recording liquid (1)) and processing liquid (processing liquid (1), (2))) was used as an ink jet printer (an experimental machine equipped with a head manufactured by Toshiba TEC, print density: 300 dpi, Using a droplet ejection frequency of 2 kHz, the number of nozzles: 64, and a two-row arrangement, 25 recording liquid droplets and a treatment liquid droplet were deposited per 1 cm ² to form an image. In this case, the recording liquid droplets were ejected at the same position as the processing liquid droplets after the treatment liquid droplets were ejected, and the recording liquid droplets did not overlap each other. In forming the image, the droplet sizes (droplet amounts) of the recording liquid and the processing liquid were varied in each of the examples and the comparative examples.
As the recording medium, a polyethylene terephthalate (PET) sheet having a thickness of 60 μm was used.

(exposure)
After printing, the recording medium on which the image was formed was exposed by the LED. In this embodiment, NCC A03C manufactured by Nichia Corporation was used as the LED. This LED outputs ultraviolet light having a wavelength of 365 nm from one chip. When a current of about 500 mA is applied, light of about 100 mW is emitted from the chip. A plurality of these are arranged at intervals of 7 mm, and a power of 0.3 W / cm ² can be obtained on the media surface. The exposure time after the droplet ejection and the exposure time can be changed according to the medium transport speed and the distance between the head and the LED transport direction. In this embodiment, the exposure is performed about 0.5 seconds after landing.
Depending on the setting of the distance to the medium and the conveyance speed, the exposure energy on the medium can be adjusted between 0.01 and 15 J / cm ² . In this embodiment, the exposure energy is adjusted according to the conveyance speed.
For the measurement of the exposure power and exposure energy, a spectroradiometer URS-40D manufactured by USHIO INC. Was used, and a value obtained by integrating the wavelength between 220 nm and 400 nm was used.
The environment during printing and exposure (printing environment) was performed under the conditions (room temperature 25 ° C., humidity 80%).

(Curability evaluation)
High quality paper was superimposed on the print sample immediately after exposure, and the following evaluation was made based on the degree of transfer of the colorant to the high quality paper when passed through a pressure roller (50 kg / cm ² ). The evaluation results are shown in Table 2.
○: No transfer at all.
Δ: Partially transferred.
X: Almost all transferred.

(Relationship between S1, S2, and S3)
At the time of exposure, the droplets printed on the recording medium were observed with an optical microscope, and the relationship among S1, S2, and S3 was judged from the size of the droplets and the degree of overlap. S1 is the vertical projection area of the recording liquid droplet onto the recording medium, S2 is the vertical projection area of the processing liquid droplet onto the recording medium, and S3 is the recording liquid droplet and the processing liquid droplet. This is the vertical projection area of the overlapping portion onto the recording medium.

From the above results, it can be seen that when printing is performed only with the recording liquid (Comparative Examples 1, 2, and 4), the curability is lowered. In particular, since the curability deteriorated under high humidity conditions, it was suggested that the polymer was strongly influenced by moisture.
When printing is performed using only the recording liquid and using the recording liquid and the processing liquid (Invention 1 to 6, Comparative Examples 3, 5, and 6), the vertical projection of the recording liquid droplet onto the recording medium is performed. The relationship among the area S1, the vertical projection area S2 of the treatment liquid droplet on the recording medium, and the vertical projection area S3 of the overlapping portion of the recording liquid droplet and the treatment liquid droplet on the recording medium is expressed as S1 <S2. And when S1 = S3, it turns out that sclerosis | hardenability has improved.
From the above, it is considered that it is possible to prevent the influence of polymerization inhibition due to moisture by printing using the recording liquid and the processing liquid.

On the other hand, if the relationship between the surface tension γ1 of the recording liquid and the surface tension γ2 of the processing liquid is “γ2> γ1,” the recording liquid covers the entire surface of the processing liquid due to the action of reducing the surface energy. The vertical projection area S1 of the droplet onto the recording medium, the vertical projection area S2 of the processing liquid droplet onto the recording medium, and the vertical projection area onto the recording medium at the overlapping portion of the recording liquid droplet and the processing liquid droplet The relationship of S3 is S1 = S2 and S1 = S3. At this time, it was found that even when the integrated energy of the LED light exceeded 100 mJ / cm ³ , the colorant was transferred to the high-quality paper and the curability of the image area was lowered. Therefore, it is considered that the relationship between the surface tension γ1 of the recording liquid and the surface tension γ2 of the treatment liquid is preferably “γ2 <γ1”.

It is sectional drawing which shows the mode of droplet (I) at the time of exposure, and droplet (II), (B) is a vertical projection figure of each droplet in the state of (A). 1 is an overall configuration diagram illustrating an example of an inkjet recording apparatus of the present invention. It is a top view which shows a liquid provision part and its periphery. (A) is a plane perspective view which shows an example of the fundamental whole structure of a droplet ejection head, (b). It is sectional drawing along the bb line in (a). It is the schematic which showed the structure of the liquid supply system in an inkjet recording device. It is a principal block diagram showing the system configuration of the ink jet recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet recording device 12 Liquid provision part 14 Liquid storage / loading part 16 Recording medium 18 Paper supply part 22 Belt conveyance part

Claims (5)

Using a recording liquid containing at least a colorant and a polymerizable compound, and a treatment liquid substantially not containing a colorant, a droplet (I) of 100 pl or less made of the recording liquid, and 100 pl or less of the treatment liquid. The droplet (II) is ejected onto a recording medium by an ink jet recording head, and after the ejection, an image is formed by polymerizing and curing by low-illuminance exposure with an illuminance on the recording medium surface of 1000 mW / cm ² or less. An ink jet recording method comprising:
The vertical projection area S1 of the droplet (I) onto the recording medium, the vertical projection area S2 of the droplet (II), and the droplet (I) and the droplet (II) at the time of low-illuminance exposure An inkjet recording method, wherein the vertical projection area S3 of the overlapping portion is S1 <S2 and S1 = S3.   2. The ink jet recording method according to claim 1, wherein the relationship between the surface tension γ1 of the recording liquid and the surface tension γ2 of the treatment liquid is γ2 <γ1 (mN / m).   The inkjet recording method according to claim 1 or 2, wherein a polymerization initiator is contained in at least one of the recording liquid and the processing liquid.   The inkjet recording method according to any one of claims 1 to 3, wherein the polymerizable compound is water-insoluble.   An ink jet recording apparatus using the ink jet recording method according to claim 1.

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