JP2011183735A - Image recording composition and recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording composition which forms a layer that is to be cured and has improved flexibility after curing compared with the case using the image recording composition containing no urethane prepolymer having a functional group. <P>SOLUTION: The image recording composition contains a liquid absorption component, a UV ray-curing monomer, a surfactant and the urethane prepolymer having the functional group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image recording composition and a recording apparatus.

  Patent Document 1 proposes a recording method in which a liquid is attached to the surface of an intermediate transfer member, an ink droplet is attached onto the liquid, and then the ink on the intermediate transfer member is transferred to the printing medium together with the liquid. Yes. In Patent Document 1, a liquid obtained by removing a dye or a pigment from the constituent material of the ink droplet is used as the liquid deposited on the intermediate transfer body prior to the ink droplet.

In Patent Document 2, a first material that reduces the fluidity of a colored ink containing a colorant is applied on an intermediate transfer member, and a colored ink is applied on the material to form an ink image, which is then formed on a recording medium. A recording method for transferring an ink image formed on the intermediate transfer member to a recording medium after applying a second material for improving the scratch resistance of the image to be printed has been proposed. A liquid containing a metal salt is used as the first material, and a liquid containing a water-soluble resin is used as the second material.
In Patent Document 3, using an intermediate transfer recording medium provided with an intermediate transfer layer made of an uncured ionizing radiation curable resin composition on one surface of a substrate, an arbitrary image is printed on the intermediate transfer layer, There has been proposed a method in which fine irregularities are formed on the surface of an intermediate transfer layer after the attached transfer layer is transferred onto the object to be cured, and cured with ionizing radiation.

Japanese Patent Application Laid-Open No. 2001-212956 JP 2005-170036 A JP 2006-76042 A

  The problem of the present invention is that, in comparison with the case where an image recording composition not containing a urethane prepolymer having a functional group is used, the layer in the cured layer formed by the image recording composition is flexible. An object of the present invention is to provide an image recording composition having improved properties.

The above problem is solved by the following means. That is,
The invention according to claim 1 is an image recording composition containing a liquid-absorbing component, an ultraviolet curable monomer, a surfactant, and a urethane prepolymer having a functional group.

  The invention according to claim 2 is the image recording composition according to claim 1, wherein the urethane prepolymer contains a propylene oxide structure.

  The invention according to claim 3 is the image recording composition according to claim 1 or 2, wherein the urethane prepolymer includes an ethylene oxide structure.

  The invention according to claim 4 is the image recording composition according to any one of claims 1 to 3, further comprising a hydrophobic monomer having a functional group and a solubility parameter of 9.6 or less. is there.

  The invention according to claim 5 is the image recording composition according to claim 4, wherein the hydrophobic monomer has at least one of a propylene oxide structure and a propylene oxide structure.

The invention according to claim 6 is an intermediate transfer member, a supply device for supplying the image recording composition according to any one of claims 1 to 5 to the intermediate transfer member, and the intermediate transfer member. An ejection device that ejects droplets containing an aqueous solvent onto a cured layer formed of the image recording composition supplied to the recording medium, and records the cured layer ejected with the droplets from the intermediate transfer member. The recording apparatus includes a transfer device for transferring to a medium and an irradiation device for irradiating the cured layer with ultraviolet rays.
The invention according to claim 7 provides a supply device for supplying the image recording composition according to any one of claims 1 to 5 to a recording medium, and the image recording supplied to the recording medium. A recording apparatus comprising: a discharge device that discharges droplets containing an aqueous solvent to a cured layer formed of a composition; and an irradiation device that irradiates ultraviolet rays onto the cured layer onto which the droplets have been discharged. is there.

  According to the first aspect of the invention, the cured layer of the layer to be cured formed of the image recording composition is compared with the case of using the image recording composition that does not contain the functional group-containing urethane prepolymer. The effect that the composition for image recording in which the flexibility was improved is provided.

  According to the invention which concerns on Claim 2, compared with the case where a urethane prepolymer does not contain a propylene oxide structure, there exists an effect that a flexibility is easily adjusted.

  According to the third aspect of the present invention, the urethane prepolymer has an effect that the adhesion to the recording medium is improved as compared with a case where the urethane prepolymer does not include an ethylene oxide structure.

  According to the invention which concerns on Claim 4, compared with the case where the hydrophobic monomer in this invention is not included, there exists an effect of suppressing the viscosity increase of the composition for image recording.

  According to the invention which concerns on Claim 5, compared with the case where a hydrophobic monomer does not contain a propylene oxide structure and an ethylene oxide structure, there exists an effect that the flexibility of the composition for image recording is adjusted easily. .

  According to the invention which concerns on Claim 6 and Claim 7, there exists an effect that the to-be-hardened layer in which the flexibility was improved is formed.

It is also a schematic diagram showing an example of a recording apparatus according to the present embodiment. It is a schematic diagram which shows an example of the recording device which concerns on this Embodiment. It is a schematic diagram which shows an example of the recording device which concerns on this Embodiment. It is a schematic diagram which shows an example of the recording device which concerns on this Embodiment.

  Hereinafter, the image recording composition and recording apparatus of the present embodiment will be described in detail.

<Image recording composition>
The image recording composition according to the present embodiment is an image recording composition containing a liquid-absorbing component, an ultraviolet curable monomer, a surfactant, and a urethane prepolymer having a functional group.

  According to the image recording composition of the present embodiment, the cured layer formed by the image recording composition is transferred to the recording medium by including a urethane prepoly having a functional group. Even after being cured by ultraviolet irradiation, it is considered that a cured layer having improved flexibility can be obtained compared to the case of using an image recording composition not containing the urethane prepolymer having the functional group. .

  In the present embodiment, a layer obtained by curing a layer to be cured by ultraviolet irradiation is referred to as a “cured layer”.

  Subsequently, each component which comprises the composition for image recording which concerns on this embodiment is demonstrated in detail.

(Urethane prepolymer having functional groups)
First, the urethane prepolymer having a functional group contained in the image recording composition of the present embodiment will be described.

The urethane prepolymer having a functional group is formed by introducing a functional group into the urethane prepolymer. In the present embodiment, “prepolymer” refers to a polymer contained in an image recording composition in a state before being cured by ultraviolet irradiation.
This urethane prepolymer having a functional group exhibits compatibility with the monomer contained in the image recording composition.

  As this urethane prepolymer, a polyester urethane prepolymer, a polyether urethane prepolymer, a polyetherester urethane prepolymer, a polycarbonate urethane prepolymer, a chain extender and an acrylate by various diamines, triamines, and the hydrolysis product thereof, In addition to substituted hydrazine and the like, glycols include ethylene glycol, propylene 1,3 glycols, some diethylene glycol, butanediol, hexanediol, octanediol, neopentylglycol, methylpropanediol, various hydroxymethylcyclohexanes And a diol chain extender using a combination of alkylene glycols and the like. Among them, a low molecular weight polyester urethane prepolymer having an acrylate having two or more functional groups or a methacrylate group is desirable from the viewpoint of affinity for water-based ink.

  In addition, commercially available urethane prepolymers include (manufactured by Toa Gosei: 2 to polyfunctional urethane acrylates such as M1600, M1200, and M1960, polyester acrylates such as the polyfunctional M6100 and M7100, and EBECRYL12 polyether manufactured by Daicel Cytec. Triacrylate, polyester urethane acrylate 8804, lactone urethane acrylate 8402, and the like.

The urethane prepolymer desirably has an alkylene oxide structure in the urethane prepolymer main chain from the viewpoint of improving the flexibility of the cured layer.
Specific examples of the alkylene oxide structure include ethylene oxide, propylene oxide, butylene oxide, pentylene oxide, hexylene oxide, and combinations thereof (which may be combined in any of random and blocks). These may be polyalkylene oxides having a repeating number of 2 to 10,000.

  Among these alkylene oxide structures, the urethane prepolymer preferably includes at least one of a propylene oxide structure and an ethylene oxide structure, and more preferably includes both.

Specific examples of urethane prepolymers having a propylene oxide structure include diols having a terminal acrylate moiety and different PPG structures (polypropylene glycol structures) having different molecular weights (molecular weight adjustment range of about 1000 to 30000), aromatics and fats. Acrylate groups or methacrylate ester bonds at both ends, which are made by reacting the group (HDI, MDI) and various isocyanates (TDI, MDI, polymeric MDI, TDDI, IPDI, XDI, hydrogenated products thereof) and connecting them with urethane bonds And a polyester urethane prepolymer having a linear structure.
Specific examples of the urethane prepolymer having an ethylene oxide structure include polyethylene glycol having a polyethylene oxide structure (molecular weight 1000 to 30000), polyfunctional isocyanates, and the like. Examples of the polyfunctional isocyanates include those esterified between a urethane bond group and an acrylic group or a methacryl group. The number of functional groups of the photoreactive acrylic residue in the urethane prepolymer having an ethylene oxide structure is adjusted from 2 to 6 (bifunctional to 6 functional). Trifunctionality is desirable.
Furthermore, as a urethane prepolymer having both a propylene oxide structure and an ethylene oxide structure, specifically, polyols having both the above PEO (polyethylene oxide structure) and PPG unit (polypropylene glycol structure) are mixed. Then, a method of prepolymerizing as a block copolymer urethane component and converting it to a diol-based urethane having an acrylic reactive group at the terminal can be mentioned.
In addition to the polyether component, the diol component is mixed with an alkyl component such as tetramethylene, butadiene, hexamethylene, a reaction product with an acrylic polyol such as a lactone ring, a caprolactone ring, or a polycarbonate. Also good.

  By adjusting the content of the propylene oxide structure in the urethane prepolymer, the flexibility of the cured layer is easily adjusted. Further, by adjusting the content of the ethylene oxide structure in the urethane prepolymer, the releasability between the intermediate belts, the ink affinity, and the adhesion of the cured layer to the recording medium can be easily adjusted.

  And, if the urethane prepolymer has both a propylene oxide structure and an ethylene oxide structure, by adjusting the blending ratio (molar ratio) of the propylene oxide structure and the ethylene oxide structure in the urethane prepolymer Adjusting the surface tension according to the recording medium on which the cured layer is formed by the image recording composition and the surface tension according to the wettability of the ink to the cured layer formed by the image recording composition Adjustment, adhesion of the cured layer to the recording medium, flexibility of the cured layer, and the like are easily adjusted.

  The content of the propylene oxide structure in the urethane prepolymer is desirably 90 mol% or less, and more desirably 20 mol% or more and 50 mol% or less.

  Further, the content of the ethylene oxide structure in the urethane prepolymer is preferably 30 mol% or more and 100 mol% or less, and more preferably 50 mol% or more and 80 mol% or less.

  When the urethane prepolymer has both a propylene oxide structure and an ethylene oxide structure, the molar ratio of the propylene oxide structure and the ethylene oxide structure in the urethane prepolymer is 10: 1 to 1: It is desirable that the adjustment is within the range of 10, and it is further desirable that the adjustment is within the range of 5: 5 to 2: 8.

  As the number average molecular weight of the above urethane prepolymer (urethane prepolymer not containing a functional group), when the urethane prepolymer does not contain the above-described alkylene oxide structure, a range of 1000 or more and 30,000 or less, or 1000 The range below 5000 is mentioned above.

  On the other hand, when the urethane prepolymer includes at least one of a propylene oxide structure and an ethylene oxide structure as the above-described alkylene oxide structure, the number average molecular weight of the urethane prepolymer is in the range of 1000 to 30000. The range below 5000 is mentioned above.

  When the urethane prepolymer contains at least one of the above-described propylene oxide structure and ethylene oxide structure, the number average molecular weight is within the above range, so that the curing time by ultraviolet irradiation (before curing) It is considered that it is suppressed that the required time is slower than other curable materials (such as ultraviolet curable monomers) contained in the image recording composition.

The number average molecular weight is measured by gel permeation chromatography (GPC). For the measurement of the number average molecular weight by GPC, HLC-8120GPC manufactured by Tosoh Corporation is used, column temperature is 40 ° C., pump flow rate is 0.4 mL / min, and RI (built in the GPC main body) is used as a detector. In the data processing, the molecular weight is obtained from the PEG-converted molecular weight using a standard PEG calibration curve with a known molecular weight (calibration at a molecular weight of 1000 or more). Hereinafter, the number average molecular weight is measured by this method.
Column used: SuperAWM-H + SuperAWM-H + SuperAW3000
Mobile phase: 10 mM LiBr + N-methylpyrrolidone Injection volume: 20 μl
Sample concentration: 0.1% (w / w)

  Examples of the functional group introduced into the urethane prepolymer include an ultraviolet curable functional group (acrylic and methacrylic group) and a photopolymerizable functional group such as a vinyl group.

  Examples of the ultraviolet curable functional group include at least one selected from the group consisting of an acryl group, a methacryl group, epoxaacrylate, and a mixture thereof. Among these, as the ultraviolet curable group, it is desirable to use an acrylic group for reasons of flexibility.

  Examples of the photoreactive functional group include at least one selected from the group consisting of 1 to polyfunctional acrylic residues. Among these, it is desirable to use a bifunctional to trifunctional acrylic group for the reasons of reactivity and adjustment of the crosslinking density.

  The functional group introduced into the urethane prepolymer may be introduced at the end of the urethane prepolymer main chain or may be introduced as a side chain of the urethane prepolymer main chain. In consideration of the reactivity of the isocyanate used, the reactivity of the acrylic component may be adjusted by introducing a hydroxy group as an unreacted residue.

  Note that the urethane prepolymer having a functional group in the present embodiment may be monofunctional or polyfunctional. The number of functional groups is preferably 1 or more and 5 or less, and more preferably 2 from the viewpoint of compatibility with other materials contained in the image recording composition.

  Specific examples of the urethane prepolymer having a functional group used in the present embodiment include a component having excellent flexibility in a combination of a polyether component and an aliphatic diisocyanate component having an adjusted molecular weight. Among these, a urethane prepolymer having a polyether acrylate component and having 2 to 3 functional acrylic groups is desirable.

  Examples of commercially available urethane prepolymers having functional groups include M1600 manufactured by Toa Gosei Co., Ltd., M1100, 1200, M6100 manufactured by Toa Gosei Co., Ltd., CN3211 manufactured by Osaka Organic Chemical Co., Ltd., and EBCRY12 manufactured by Daicel-Cytec. .

As a method for introducing a functional group into a urethane prepolymer, a method using a functional group as a part of a monomer of a long-chain diol, a method using a part of a short-chain diol, or a urethane prepolymer obtained by polymerizing polyurethane Thereafter, a method of introducing a functional group by a polymer reaction may be mentioned. Further, in combination with a monomer component having a urethane bond, for example, mixing with propylene oxide-modified acrylates having an isocyanic acid structure, ethylene oxide-modified acrylates, etc., flexibility and adhesion can be adjusted.

  Examples of the content of the urethane prepolymer having a functional group in the image recording composition of the present embodiment include 1% by mass to 30% by mass, or 1% by mass to 10% by mass. In the present embodiment, the urethane prepolymer having a functional group is adjusted in molecular weight, type and number of functional groups, viscosity thereof, and the like, with a small addition amount as described above in the image recording composition. Even if it exists, it is thought that the flexibility is implement | achieved, maintaining the adhesiveness to the recording medium of the hardened layer formed of the composition for image recording.

The surface tension of the urethane prepolymer having a functional group is adjusted in the range of, for example, 20 mN / m or more and 50 mN / m or less from the viewpoint of suppressing increase in viscosity of the image recording composition and suppressing decrease in water resistance. It is good to be done.
This surface tension is prepared by the number average molecular weight, skeleton, functional group, and the like of the urethane prepolymer having a functional group.

(Liquid absorption component)
Next, the liquid absorbing component contained in the image recording composition of the present embodiment will be described.

  The image recording composition contains a liquid-absorbing component that absorbs ink as a material for fixing the colorant in the ink. This liquid-absorbing component contains a liquid-absorbing material as a main component. The “main component” refers to a component containing 50% by mass or more based on the whole. The liquid absorbing material means that the liquid absorbing material and the ink are mixed at a weight ratio of 30: 100 for 24 hours, and then the weight of the liquid absorbing material is equal to the weight of the liquid absorbing material when the liquid absorbing material is taken out from the mixed solution with a filter. It is increased by 5% or more compared with that before mixing.

Examples of the liquid-absorbing material include a resin (hereinafter sometimes referred to as a liquid-absorbing resin), inorganic particles (for example, silica, alumina, zeolite, etc.) having surface ink affinity, and the ink used. It is appropriately selected depending on.
Specifically, when water-based ink is used as the ink, it is desirable to use a water-absorbing material as the liquid-absorbing material. When oil-based ink is used as the ink, it is desirable to use an oil-absorbing material as the liquid-absorbing material.

  Specific examples of the water-absorbing material include polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, (meth) acrylic acid ester- (meth) acrylic acid and salts thereof, and styrene. -Copolymer composed of (meth) acrylic acid and its salt, styrene- (meth) acrylic ester-Copolymer composed of (meth) acrylic acid and its salt, styrene- (meth) acrylic ester A copolymer composed of an ester formed from an alcohol having an aliphatic or aromatic substituent having a carboxylic acid and a salt structure thereof and (meth) acrylic acid, (meth) acrylic acid ester-carboxylic acid and a salt thereof Copolymer composed of ester formed from alcohol having aliphatic or aromatic substituent having structure and (meth) acrylic acid Copolymer composed of ethylene- (meth) acrylic acid copolymer, butadiene- (meth) acrylic ester- (meth) acrylic acid and salts thereof, butadiene- (meth) acrylic ester-carboxylic acid and salts thereof A copolymer composed of an ester formed from an alcohol having an aliphatic or aromatic substituent having a structure and (meth) acrylic acid, a polymaleic acid and a salt thereof, a copolymer composed of styrene-maleic acid and a salt thereof Examples thereof include sulfonic acid-modified products of the respective resins, phosphoric acid-modified products of the respective resins, and the like, preferably from polyacrylic acid and salts thereof, styrene- (meth) acrylic acid and salts thereof. Consists of copolymer, styrene- (meth) acrylic acid ester- (meth) acrylic acid and its salts A copolymer composed of an ester produced from (meth) acrylic acid, an alcohol having an aliphatic or aromatic substituent having a styrene- (meth) acrylic acid ester-carboxylic acid and a salt structure thereof, and (Meth) acrylic acid ester- (meth) acrylic acid and a copolymer composed of a salt thereof. These resins may be uncrosslinked or crosslinked.

  Specific examples of the oil-absorbing material include low-molecular gelling agents such as hydroxystearic acid, cholesterol derivatives, and benzylidene sorbitol, polynorbornene, polystyrene, polypropylene, styrene-butadiene copolymers, and various rosins. Desirably, polynorbornene, polypropylene, and rosins are used.

  The liquid-absorbing component may be in the form of solid particles, or it may be in a state where the liquid is dispersed in the cured layer, such as an emulsion, or in a semi-dissolved state (for example, the polymer chain is broken and the molecular chain is extended) State).

  The diameter (volume average particle diameter) of the liquid-absorbing component is preferably in the range of 0.05 μm to 25 μm, and more preferably 0.05 μm to 5 μm.

  The specific gravity of the liquid-absorbing component is preferably relatively smaller than the specific gravity of the curable material contained in the image recording composition. The ratio of the liquid-absorbing component to the entire image recording composition is preferably 1% or more and 60% or less, more preferably 10% or more and 50% or less, and even more preferably 20% or more and 40% or less in terms of mass ratio. .

  When the liquid-absorbing component is resin particles containing a liquid-absorbing material, examples of a method for preparing the resin particles include a method of pulverizing a resin containing a liquid-absorbing material with a ball mill.

(Surfactant)
Next, the surfactant contained in the image recording composition of the present embodiment will be described.

  Examples of the surfactant contained in the image recording composition of the present embodiment include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. Among these, it is desirable to use an anionic surfactant or a nonionic surfactant, and a nonionic surfactant is particularly desirable.

  Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfuric acid of higher alcohol ether. Ester salts and sulfonates, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, etc. are used, preferably , Dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, monobutylbiphenylsulfonate, dibutylphenylsulfonate Nord disulfonic acid salts and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, poly Oxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkyl alkanolamide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, polyoxyethylene adduct of acetylene glycol Desirably, polyoxyethylene nonyl pheny is preferable. Ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, polyethylene glycol polypropylene glycol block copolymer , Acetylene glycol, and polyoxyethylene adducts of acetylene glycol.

  In addition, silicone surfactants such as polysiloxane oxyethylene adducts, fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers, spicrispolic acid and rhamnolipids Biosurfactants such as lysolecithin are also used as surfactants.

  These surfactants may be used alone or in combination. The hydrophilic / hydrophobic balance (hereinafter referred to as “HLB”) of the surfactant is preferably 8 or more and 18 or less in consideration of solubility and the like.

The hydrophilic group / hydrophobic group balance (HLB) is defined by the following formula (Griffin method).
・ HLB = 20 × (sum of formula weight of hydrophilic part / molecular weight)

  The surfactant is desirably modified with a silicone component for reasons of nonionic, liquid-absorbing particles controlled by HLB and monomer compatibility. Specific examples of the silicone component include photoreactivity having a side chain modified with a dimethylsiloxane derivative and a PPG / PEO component and an acrylic residue, and a certain degree of viscosity. As a method of modifying these surfactants with a silicone component, a known method may be used.

  Examples of the surfactant modified with the silicone component include a dimethyl silicone polymer having at least one of a polyethylene glycol component and a polypropylene glycol component as a side chain.

  Here, when the image recording composition contains a silicone-modified surfactant, adhesion to the recording medium is reduced during transfer of the cured layer formed of the image recording composition to the recording medium. However, the urethane prepolymer containing the above-mentioned ethylene oxide structure is used as the urethane prepolymer, and the adhesiveness of the cured layer to the recording medium is improved by adjusting the content of the ethylene oxide structure. In addition, it is considered that the wettability of the ink to the cured layer is improved.

  As the surfactant, a surfactant having an ultraviolet curable group may be used. Examples of the ultraviolet curable group include the functional groups listed above as the “functional group having ultraviolet curable properties”.

  The content of the surfactant in the image recording composition of the present embodiment is preferably from 0.1% by mass to 30% by mass, or more preferably from 0.5% by mass to 10% by mass.

(UV curable monomer)
The ultraviolet curable monomer contained in the image recording composition of the present embodiment may be any monomer having an ultraviolet curable group.

  The above-described urethane prepolypolymer having a functional group and an ultraviolet curable monomer are used in combination with the image recording composition of the present embodiment, thereby reducing the film thickness and reactivity due to a decrease in the viscosity of the blended dispersion. It is considered that the following effects can be obtained: control of liquid, compatibility with liquid-absorbing components, uniform dispersibility of the surfactant, and suppression of uneven distribution.

  Examples of the ultraviolet curable group include the functional groups listed above as the “functional group having ultraviolet curable properties”. Among these, as the ultraviolet curable group contained in the ultraviolet curable monomer, a methacryl group and an acrylic group are desirable for reasons of volatility, reactivity, and flexibility.

  Specific examples of the ultraviolet curable monomer include pentyl glycol diacrylate, glycidol dimethacrylate, cyanuric triacrylic ester, pentaerythritol triacrylate, trimethylolpropane ethoxytriacrylate, glyceryl propoxytriacrylate, dipentaerythritol hexaacrylate, Various hydroxy acrylates (HEA, HEMA, HPA, GDMA, PETA) and special acrylates include cyanuric acid-modified acrylate derivatives, polyethylene glycol-modified acrylates, polypropylene glycol-modified acrylates, fail-modified EO, PO acrylate, N-vinyl pyrrolidone, etc. One or more of these are used in combination.

  Among the UV curable monomers listed above, monofunctional monomers and polyfunctional monomers are used in combination for reactivity, urethane prepolymer compatibility, and viscosity adjustment, and there is some ink compatibility and liquid-absorbing particle swelling properties. Trimethylolpropane EO-modified acrylates, isocyanaric acid EO-modified acrylates, hydroxypropyl acrylates (monofunctional), and those having 2 to 3 functional groups are preferably used.

  The content of the ultraviolet curable monomer in the image recording composition of the present embodiment is preferably 1% by mass to 30% by mass, and more preferably 1% by mass to 10% by mass.

(Other materials included in image recording composition)
In addition to the above-described urethane prepolymer having a functional group, a liquid-absorbing component, a surfactant, and an ultraviolet curable monomer, the image recording composition of the present embodiment further comprises the following materials. An added configuration may be used.

The image recording composition of the present embodiment preferably further contains a hydrophobic monomer having a functional group and a solubility parameter (sp value) of 7 or more and 9.6 or less, and a hydrophobicity of 8 or more and 9.6 or less. It is further desirable to include at least one type of functional monomer.
Monomers having an sp value of 9.6 or less include neopentyl glycol diacrylate and its derivatives, hexanediol diacrylate, tripropylene glycol diacrylate, dipentaerythritol polyfunctional, various ethylene oxide-modified phenoxy acrylates, alkoxyalkyl Examples include acrylate, cyclohexyl acrylate, and cyclopentadiene acrylate.

The total content of the hydrophobic monomer exhibiting the sp value in the image recording composition is preferably in the range of 1% by mass to 30% by mass, and in the range of 5% by mass to 30% by mass. It is particularly desirable that

  By using the hydrophobic monomer in combination with the image recording composition of the present embodiment, an increase in the viscosity of the image recording composition is suppressed. In addition, when the hydrophobic monomer is used in combination with the image recording composition of the present embodiment, inhibition of liquid absorption of the image area by the ink ejected to the cured layer, image quality unevenness, density unevenness, and the like are also suppressed. It is thought that it is done.

  Hydrophobic monomers having a solubility parameter in the above-mentioned range may be used as a mixture of one or more, but this hydrophobic monomer is preferably monofunctional, bifunctional, or trifunctional. It is further desirable to be functional. Since the monofunctional, bifunctional, or trifunctional hydrophobic monomer is contained in the image recording composition, aggregation of the liquid-absorbing component contained in the image recording composition is suppressed, and the image recording composition It is considered that the increase in viscosity of the product is suppressed and the dispersion uniformity is controlled. For this reason, it is thought that the dispersion | variation in the layer thickness of the to-be-hardened layer formed with the composition for image recording is suppressed.

  Examples of the functional group possessed by the hydrophobic monomer include a functional group having a long-chain alkoxy group, such as an alkyl group, a cyclic alkyl group, a branched alkoxy group, cyclohexyl, or a dimethylsiloxane derivative. Specifically, lauryl Group, dodecyl group, hexamethylene group, pentaerythritol derivative, trimethylolpropane derivative, cyclohexyl derivative, butanediol, low molecular weight polyethylene glycol (molecular weight 200) derivative and the like.

Among these, as a functional group which a hydrophobic monomer has, a lauryl group and a dodecyl group are desirable.
The curing reactivity of the above-mentioned urethane prepolymer having a functional group contained in the image recording composition is easily affected by the molecular weight, the number of functional groups, the type of functional group, the branched state, etc. By using a hydrophobic monomer having at least one of a lauryl group and a dodecyl group in the composition, compatibility between components contained in the composition for image recording and uniformity of curing reaction upon irradiation with ultraviolet rays It is also considered that the flexibility of the cured layer is further improved. For this reason, when the layer to be cured formed of the image recording composition is transferred to a recording medium and irradiated with ultraviolet rays to form a cured layer, the ultraviolet irradiation time is, for example, an amount of light of less than 200 mJ / cm ^{2 and} irradiation of 100 msec. Even if it is, it is thought that the fall of the adhesiveness of the hardened layer to the recording medium is further suppressed, and the flexibility is further improved.

  In addition, the hydrophobic monomer preferably includes an alkylene oxide structure, more preferably includes at least one of a propylene oxide structure and an ethylene oxide structure, and includes both the propylene oxide structure and the ethylene oxide structure. It is particularly desirable to include.

  Hereinafter, an example of a hydrophobic monomer having a functional group and having an sp value of 9.6 or less is shown below. The numbers in () are sp values. The sp value is obtained from the structural formula of the compound by the fedors method.

Tetrahydrofurfuryl acrylate (THFA) (9.6), cyclohexyl acrylate (CHA) (9.6), isobornyl methacrylate (IBXMA) (9.6), ethylhexyl acrylate (HA) (8.9), dodecyl methacrylate ( DMA) (8.8), and lauryl acrylate (LA) (8.7) phenoxy (ethylene glycol) n = 4 or more monofunctional hydrophobic monomers such as acrylate (9.4) and ethoxyethylene oxide acrylate (8.3) ), Dipropylene glycol 1000 or more diacrylate (8.6), 1,6-hexadiol acrylate (9.6), diacrylates having a polyol main chain (PEG 200) (8.8), PEG 400 (8. 5), PEG600 (8.4), etc. Manufactured by Tech), and bifunctional hydrophobic monomers such as neopentyl glycol diacrylate (9.4) glycidol dimethacrylate (9.1),
Methoxypolyethylene glycol (n = 8): (9.3), pentamethylpiperidyl methacrylate (8.7), tetrahydrofluacrylate (9.2), dicyclopentanyl acrylate (9.3), di- or tripropylene chloride Recall acrylate (9 or more and 9.5 or less), vinyloxyethoxy acrylate) ethyl (8.7), and its methacrylic acid derivative (8.7), ethylene oxide-modified polypropylene glycol dimethacrylate (8.2), neo Various polyether modified, alicyclic, such as pentyl glycol diacrylate (9.4), polypropylene glycol (8.2), glycene propoxy triacrylate (9.2), trimethylol ethoxy triacrylate (9.1) What consists of acrylates is mentioned.

Next, other curable materials that may be contained in the image recording composition will be described.
The component having an ultraviolet curable group (the above-mentioned ultraviolet curable monomer) contained in the image recording composition functions as a curable material that is cured by irradiation with ultraviolet rays. However, the image recording composition has a curable property. As a material, the following curable material may be further added.

  Examples of the curable material include an ultraviolet curable monomer, an ultraviolet curable macromer, an ultraviolet curable oligomer, and an ultraviolet curable prepolymer.

  Examples of the ultraviolet curable monomer include alcohol / polyhydric alcohol / amino alcohol acrylic esters, alcohol / polyhydric alcohol methacrylates, acrylic aliphatic amides, acrylic alicyclic amides, and acrylic aromatic amides. Curable materials such as epoxy monomers; curable materials such as epoxy monomers, oxetane monomers, vinyl ether monomers; and the like. Examples of the ultraviolet curable macromer, the ultraviolet curable oligomer, and the ultraviolet curable prepolymer include those obtained by polymerizing these monomers at a predetermined polymerization degree, epoxy, urethane, polyester, polyether skeleton, acryloyl group, Examples thereof include epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, urethane methacrylate, and polyester methacrylate to which a methacryloyl group is added.

  The curable material contained in the image recording composition is desirably a silicone-modified silicone compound.

  The image recording composition preferably contains an ultraviolet polymerization initiator for allowing the ultraviolet curing reaction to proceed. Furthermore, the image recording composition may contain a reaction aid, a polymerization accelerator and the like for further proceeding the polymerization reaction, if necessary.

When the ultraviolet curing reaction in the image recording composition proceeds by a radical reaction, examples of the ultraviolet polymerization initiator include benzophenone, thioxanthone, benzyldimethyl ketal, α-hydroxyketone, α-hydroxyalkylphenone, α- Examples include amino ketone, α-aminoalkylphenone, monoacylphosphine oxide, bisacylphosphine oxide, hydroxybenzophenone, aminobenzophenone, titanocene type, oxime ester type, and oxyphenylacetate type.
When the ultraviolet curing reaction in the image recording composition proceeds by a cation reaction, examples of the ultraviolet polymerization initiator include arylsulfonium salts, aryldiazonium salts, diaryliodonium salts, triarylsulfonium salts, and allene-ion complexes. Examples thereof include derivatives and triazine initiators.

  The image recording composition according to this embodiment may be mixed with wax or rubber-like substances.

  Further, the image recording composition according to the present embodiment may further include a component for immobilizing the ink component on or inside the cured layer (hereinafter sometimes referred to as “immobilization component”). Good.

  Examples of the immobilization component include, but are not limited to, a component that adsorbs an ink component (for example, a coloring material) and a component that aggregates or thickens an ink component (for example, a coloring material). .

  Further, the image recording composition may contain water or an organic solvent for dissolving or dispersing the component contributing to the curing reaction.

  The image recording composition may contain various color materials for the purpose of controlling the color of the cured layer.

  In addition, the image recording composition may contain a thermoplastic resin for the purpose of adjusting the viscosity. Examples of the thermoplastic resin include acrylic resin, polyester resin, polycarbonate resin, polyurethane resin, polystyrene, polyether resin, polyethylene resin, polypropylene resin, polystyrene and its acrylic monomer copolymer and blends thereof. It is done.

  Examples of the surface tension of the image recording composition of the present embodiment include a range of 20 mN / m to 50 mN / m.

The image recording composition is used in this embodiment with a viscosity of 5 mPa · s to 30000 mPa · s, and the viscosity of the image recording composition is preferably higher than the viscosity of the ink.
The viscosity is a value measured by the following method, and the viscosity described in the present specification is a value measured by the following method.
As a viscometer, TV-22 (manufactured by Toki Sangyo Co., Ltd.) was used, and the viscosity (mPa · s) at 15 ° C. was measured at a shear rate = 2.25 to 750 (1 / s). In addition, it is a thing of the description speed 10s ^-1 in this specification.

  The image recording composition is preferably low-volatile or non-volatile at room temperature (25 ° C.). Here, low volatility means that the boiling point is 200 ° C. or higher under atmospheric pressure. Nonvolatile means that the boiling point is 300 ° C. or higher under atmospheric pressure.

(ink)
Next, the ink used in this embodiment will be described in detail. This ink corresponds to a droplet discharged to the cured layer in the recording apparatus of the present invention.
The ink can be used for both water-based ink and oil-based ink, but water-based ink is used from the viewpoint of environment. Aqueous ink (hereinafter simply referred to as ink) contains an ink solvent (for example, water, a water-soluble organic solvent) in addition to the recording material. In addition, other additives may be included as necessary.

  First, the recording material will be described. As the recording material, a color material is mainly used. As the color material, either a dye or a pigment can be used, but a pigment is preferable. As these coloring materials, known materials may be used.

  Other recording materials include hydrophilic anionic dyes, direct dyes, cationic dyes, reactive dyes, dyes such as polymer dyes and oil-soluble dyes, wax powders / resin powders and emulsions colored with dyes, Fluorescent dyes and fluorescent pigments, infrared absorbers, ultraviolet absorbers, magnetic materials such as ferromagnetic materials represented by ferrite and magnetite, semiconductors and photocatalysts represented by titanium oxide and zinc oxide, and other organic and inorganic electrons Examples include material particles.

  The content (density) of the recording material is, for example, in the range of 5% by mass to 30% by mass with respect to the ink.

Examples of the volume average particle diameter of the recording material include a range of 10 nm to 1000 nm.
The volume average particle diameter of the recording material refers to the particle diameter of the recording material itself, or the particle diameter to which the additive has adhered when an additive such as a dispersant is attached to the recording material. A Microtrac UPA particle size analyzer 9340 (manufactured by Leeds & Northrup) was used as the volume average particle diameter measuring apparatus. The measurement was performed according to a predetermined measurement method with 4 ml of ink placed in a measurement cell. As input values at the time of measurement, the viscosity of the ink was used as the viscosity, and the density of the dispersed particles was used as the recording material density.

  Next, the water-soluble organic solvent will be described. As the water-soluble organic solvent, polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, sulfur-containing solvents and the like are used.

  At least one kind of water-soluble organic solvent may be used. The content of the water-soluble organic solvent is, for example, in the range of 1% by mass to 70% by mass.

  Next, water will be described. As water, it is desirable to use ion-exchanged water, ultrapure water, distilled water, and ultrafiltered water from the viewpoint of preventing impurities from being mixed.

  Next, other additives will be described. A surfactant may be added to the ink.

  Examples of these surfactants include various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and the like. Desirably, anionic surfactants and nonionic surfactants are used. An activator is used.

  In addition, the ink contains other components such as penetrants for the purpose of adjusting the penetrability, polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethylene glycol, ethylcellulose, carboxymethylcellulose, etc. In order to adjust pH, compounds of alkali metals such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc., pH buffer, antioxidant, antifungal agent, viscosity adjuster, conductive agent as necessary Further, an ultraviolet absorber, a chelating agent and the like are also added.

  Next, preferred characteristics of the ink will be described. First, the surface tension of the ink is, for example, in the range of 20 mN / m to 45 mN / m.

  Here, as the surface tension, a value measured in an environment of 23 ° C. and 55% RH using a Wilhelmy type surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.) was adopted.

Examples of the viscosity of the ink include a range of 1.5 mPa · s to 30 mPa · s. Here, as the viscosity, a value measured using a rheomat 115 (manufactured by Contraves) as a measuring device under the conditions of a measurement temperature of 23 ° C. and a shear rate of 1400 s ⁻¹ was adopted.

  The ink is not limited to the above configuration. In addition to the recording material, for example, a functional material such as a liquid crystal material or an electronic material may be included.

<Recording device>
Next, a recording apparatus to which the image recording composition of the present embodiment is applied will be described.
The recording apparatus according to the present embodiment is formed by an intermediate transfer member, a supply device that supplies the above-described image recording composition onto the intermediate transfer member, and the image recording composition supplied onto the intermediate transfer member. The curing device is cured by irradiating ultraviolet rays to the ejection device that ejects the ink to the cured layer, the transfer device that transfers the cured layer from which the ink has been ejected to the recording medium. An irradiating device.

  Further, another aspect of the recording apparatus according to the present embodiment is formed by a supply device that supplies the above-described image recording composition onto a recording medium, and the image recording composition that is supplied onto the recording medium. The cured layer includes an ejection device that ejects the ink, and an irradiation device that cures the cured layer by irradiating ultraviolet rays.

  Next, the recording apparatus according to the present embodiment will be described with reference to the drawings. In addition, the same code | symbol is provided to the member which has the same function through all the drawings, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a configuration diagram illustrating a recording apparatus according to the first embodiment.

  As shown in FIG. 1, the recording apparatus 101 according to the first embodiment includes, for example, an intermediate transfer drum (intermediate transfer member) 10, an anionic liquid absorbing material on the intermediate transfer drum 10, and external stimulation (energy). A solution supply device 12 for supplying the image recording composition 12A containing at least a curable resin precursor that is cured by the above-described method to form a cured layer 12B formed of the image recording composition 12A; and a cured layer 12B An ink jet recording head 14 for ejecting ink droplets 14 </ b> A to form an image T, and a cured layer 12 </ b> B on which the image T is formed by applying a pressure by superimposing the recording medium P on the intermediate transfer drum 10, And a irradiating device 18 for supplying a curing stimulus for irradiating the cured layer 12B transferred onto the recording medium P with ultraviolet rays. To have.

  Further, downstream of the transfer device 16 in the rotation direction of the intermediate transfer drum 10, removal of the residue of the cured layer 12B remaining on the surface of the intermediate transfer drum 10 and foreign matters other than the residue (paper dust of the recording medium P, etc.) A cleaning device 20 for removing the deposits such as) is disposed.

The intermediate transfer drum 10 may have a configuration including, for example, a cylindrical substrate and a surface layer coated on the surface of the substrate. The intermediate transfer drum 10 has a width (length in the axial direction) equal to or greater than the width of the recording medium P.
Examples of the material of the cylindrical base include aluminum, stainless steel (SUS), and copper.
Examples of the material for the surface layer include various resins [for example, polyimide, polyamideimide, polyester, polyurethane, polyamide, polyethersulfone, fluorine resin, etc.], various rubbers (for example, nitrile rubber, ethylene propylene rubber, Chloroprene rubber, isoprene rubber, styrene rubber, butadiene rubber, butyl rubber, chlorosulfonated polyethylene, urethane rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluorine rubber, etc.). The surface layer may have a single layer structure or a stacked structure.

  The solution supply device 12 includes, for example, a supply roller 12D that supplies the image recording composition 12A to the intermediate transfer drum 10 in a housing 12C that stores the image recording composition 12A, and the supplied image recording composition. And a blade 12E that defines the layer thickness of the layer to be cured 12B formed by the object 12A.

  The solution supply device 12 may be configured such that the supply roller 12 </ b> D continuously contacts the intermediate transfer drum 10 or is separated from the intermediate transfer drum 10. Alternatively, the solution supply device 12 may supply the image recording composition 12A to the housing 12C from an independent solution supply system (not shown) so that the supply of the image recording composition 12A is not interrupted.

  The solution supply device 12 is not limited to the above-described configuration, and a known supply method (coating method: for example, bar coater coating, spray coating, ink jet coating, air knife coating, blade coating, roll coating) An apparatus using a method such as application) is applied.

  The inkjet recording head 14 includes, for example, a recording head 14K for discharging black ink, a recording head 14C for discharging cyan ink, and a magenta ink from the upstream side in the rotation direction of the intermediate transfer drum 10. The recording head 14 </ b> M and the recording head 14 </ b> Y for ejecting yellow ink are configured to include recording heads for each color. Of course, the configuration of the recording head 14 is not limited to the above configuration, and may be configured by only the recording head 14K, or may be configured by only the recording head 14C, the recording head 14M, and the recording head 14Y.

  For example, a line type ink jet recording head having a width equal to or larger than the width of the recording medium P is used for each recording head 14, but a conventional scanning ink jet recording head may be used. The ink ejection method of each recording head 14 is not limited as long as it is a method capable of ejecting ink, such as a piezoelectric element driving type and a heating element driving type.

  For example, the recording heads 14 are arranged in series in the order of the recording head 14K, the recording head 14C, the recording head 14M, and the recording head 14Y from the upstream side in the rotation direction of the intermediate transfer drum 10.

  Each recording head 14 is arranged such that the distance between the surface of the intermediate transfer drum 10 and the nozzle surface of the head is, for example, about 0.3 to 0.7 mm. Each recording head 14 is disposed, for example, such that its longitudinal direction intersects (preferably orthogonally intersects) the rotational direction of the intermediate transfer drum.

  The transfer device 16 includes a pressure roll 16 </ b> A disposed so as to be pressed against the intermediate transfer drum 10. The pressure roll 16 </ b> A is configured as in the material configuration of the intermediate transfer drum 10, for example.

  The irradiation device 18 is an ultraviolet irradiation device that irradiates the image recording composition 12A (the cured layer 12B formed thereby) with ultraviolet rays.

  As this ultraviolet irradiation device, for example, a metal halide lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a deep ultraviolet lamp, a lamp that uses a microwave to excite a mercury lamp from the outside without electrode, an ultraviolet laser, a xenon lamp, a UV-LED, etc. are applied. Is done.

  The ultraviolet irradiation condition is not particularly limited as long as the image recording composition 12A (the cured layer 12B formed thereby) is cured. For example, the high pressure mercury lamp 120 W / cm output density is 2 Irradiate for 2 seconds.

  Each cured state refers to a state in which permeable paper (plain paper) is superimposed on the cured layer obtained by curing the layer to be cured 12B by the irradiation device 18 and no transfer occurs even when a load of 200 g is applied.

  As the recording medium P, a penetrating medium (for example, plain paper or coated paper) or a non-penetrating medium (for example, art paper, resin film, metal film, or the like) is applied. Examples of the resin film include a polyethylene terephthalate (PET) film, a polycarbonate (PC) film, a polymethyl methacrylate (PMMA) film, and a polyphenylene oxide (PPO) film. Moreover, an aluminum film is mentioned as a metal film. The recording medium is not limited to these, and includes other industrial products such as semiconductor substrates.

  Hereinafter, an image recording process of the recording apparatus 101 according to the present embodiment will be described.

  In the recording apparatus 101 according to this embodiment, the intermediate transfer drum 10 is rotationally driven, and first, the image recording composition 12A is supplied to the surface of the intermediate transfer drum 10 by the solution supply apparatus 12 to form the cured layer 12B. To do.

  Here, the thickness of the curable layer 12B is not particularly limited, but is prepared in the range of 1 μm to 50 μm, for example.

  Further, for example, if the thickness of the cured layer 12B is set such that the ink droplet 14A does not reach the lowermost layer of the cured layer 12B, the ink droplet 14A exists in the cured layer 12B after transfer to the recording medium P. The area where the area is not exposed and the ink droplet 14A does not exist functions as a protective layer after curing.

  Next, the ink droplets 14 </ b> A are ejected by the inkjet recording head 14, and the ink droplets 14 </ b> A are applied to the cured layer 12 </ b> B supplied on the intermediate transfer drum 10. The ink jet recording head 14 applies ink droplets 14A to predetermined positions of the cured layer 12B based on predetermined image information.

  At this time, the ink droplets 14 </ b> A are ejected by the inkjet recording head 14 on the intermediate transfer drum 10. That is, the ink droplets 14A are ejected to the cured layer 12B in a state where the drum surface is not bent.

  Next, the recording medium P is sandwiched between the intermediate transfer drum 10 by the transfer device 16 and pressure is applied to the cured layer 12B, so that the cured layer 12B on which the image is formed by the ink droplets 14A is formed on the recording medium P. Transcribed.

  Next, the irradiating device 18 cures the curable layer 12B, whereby the image T by the ink droplet 14A is fixed on the recording medium P by the curable resin. Thereby, a curable resin layer (image layer) including the image T by the ink droplet 14A is formed on the recording medium P.

  In the present embodiment, since the image recording composition described above is used, the cured layer formed on the recording medium P (the state after the cured layer 12B is cured) is applied to the recording medium P. The adhesion is 1 N / 25 mm or more, and the Shore D hardness (JIS K7215) is 80 degrees or less, so that the adhesiveness to the recording medium P is maintained and the flexibility of the cured layer is realized. it is conceivable that.

  After the cured layer 12B is transferred to the recording medium P, the residue and foreign matter on the cured layer 12B remaining on the surface of the intermediate transfer drum 10 are removed by the cleaning device 20, and the solution is supplied onto the intermediate transfer drum 10 again. The image recording composition 12A is supplied from the apparatus 12 to form the cured layer 12B, and the image recording process is repeated.

  As described above, the recording apparatus 101 according to the present embodiment performs image recording.

  FIG. 2 is a configuration diagram illustrating a recording apparatus according to the second embodiment.

  As shown in FIG. 2, the recording apparatus 102 according to the second embodiment has a configuration in which an intermediate transfer belt (intermediate transfer member) 22 is disposed instead of the intermediate transfer drum 10 in the first embodiment.

  For example, the intermediate transfer belt 22 is rotatably supported by two support rolls 22A and a pressure roll 16B (transfer device 16) while applying tension from the inner peripheral surface side.

The intermediate transfer belt 22 has a width (length in the axial direction) equal to or greater than the width of the recording medium P.
The intermediate transfer belt 22 includes, for example, various resins [for example, polyimide, polyamideimide, polyester, polyurethane, polyamide, polyethersulfone, fluorine resin, and the like] and various rubbers (for example, nitrile rubber, ethylene propylene rubber, chloroprene). Rubber, isoprene rubber, styrene rubber, butadiene rubber, butyl rubber, chlorosulfonated polyethylene, urethane rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluorine rubber, etc.). The intermediate transfer belt 22 may be made of a metal material such as stainless steel. The intermediate transfer belt 22 may have a single layer configuration or a stacked configuration. Further, the intermediate transfer belt 22 may have a surface layer made of a releasable material such as a fluororesin or silicone rubber.

  Each recording head 14 has a non-bending region in the intermediate transfer belt that is rotationally supported under tension, and the distance between the surface of the intermediate transfer belt 22 and the nozzle surface of the head is, for example, about 0.7 mm to 1.5 mm. Are arranged.

  The transfer device 16 includes a pair of pressure rolls 16A and 16B arranged to face each other with the intermediate transfer belt 22 interposed therebetween.

  In the recording apparatus 102 according to the present embodiment, ink droplets 14 </ b> A are ejected by the inkjet recording head 14, and the ink droplets 14 </ b> A are applied to the cured layer 12 </ b> B formed on the intermediate transfer belt 22.

  At this time, the ejection of the ink droplets 14A by the ink jet recording head 14 is performed on a non-bent region in the intermediate transfer belt 22 that is rotated and supported by tension. That is, the ink droplets 14A are ejected to the cured layer 12B with the belt surface not deflected.

  Except for these, the aspects described in the first embodiment are applied, and thus the description thereof is omitted.

  FIG. 3 is a configuration diagram illustrating a recording apparatus according to the third embodiment.

  As shown in FIG. 3, the recording apparatus 103 according to the third embodiment is configured so that, in the first embodiment, before the layer to be cured 12 </ b> B formed with the ink droplets 14 </ b> A is transferred to the recording medium P, A second stimulus supply device 24 for supplying a stimulus for semi-curing the layer 12B is further arranged.

  For example, the second stimulus supply device 24 is disposed downstream of the inkjet recording head 14 in the rotation direction of the intermediate transfer drum 10 and upstream of the transfer device 16.

  The second stimulus supply device 24 applies, as the irradiation device 18, an ultraviolet irradiation device that irradiates the image recording composition 12 </ b> A (the cured layer 12 </ b> B formed thereby) with ultraviolet rays.

  The ultraviolet irradiation condition in the second stimulus supply device 24 is such that the layer to be cured 12B on the intermediate transfer drum 10 to which the ink droplets 14A are applied by the ink jet recording head 14 is semi-cured and applied to the recording medium P by the transfer device 16. There is no particular limitation as long as it is a transfer condition, and it can be selected according to the curable resin precursor species, the thickness of the layer to be cured, and the like.

  In the present embodiment, the second stimulus supply device 24 is arranged on the downstream side of the ink jet recording head 14 and the upstream side of the transfer device 16, but the second stimulus supply device 24 is arranged on the ink jet recording head. You may arrange | position upstream from 14.

  Here, the “semi-cured state” means that the image recording composition has not reached the “cured state”, but is hardened and not in a completely liquid state when supplied to the intermediate transfer member. State. One method for confirming the “semi-cured state” is as follows. Specifically, when permeable paper (for example, plain paper) is superimposed on the cured layer 12B, the cured layer 12B is not transferred to the paper side at all when no load is applied, and when a 200 g load is applied. When a part of the image is transferred, it is determined as a “semi-cured state”.

  In the recording apparatus 103 according to the present embodiment described above, the ink droplets 14A are ejected by the ink jet recording head 14, and the ink droplets 14A are applied to the cured layer 12B supplied onto the intermediate transfer drum 10, and then the second. The stimulus supply device 24 semi-cures the layer 12B to be cured. Then, the cured layer 12B is transferred to the recording medium P by the transfer device 16. During this transfer, the cured layer 12B is transferred to the recording medium P in a semi-cured state, that is, in a state having some rigidity.

  Except for these, the aspects described in the first embodiment are applied, and thus the description thereof is omitted.

  FIG. 4 is a configuration diagram illustrating a recording apparatus according to the fourth embodiment.

  As shown in FIG. 4, the recording apparatus 104 according to the fourth embodiment has a form (direct recording method) in which an image is directly formed on a recording medium P.

  The recording apparatus 104 supplies an image recording composition 12A containing, for example, an anionic liquid-absorbing material and a curable resin precursor that is cured by an external stimulus (energy) onto the recording medium P to record an image. Solution supply device 12 for forming cured layer 12B formed of composition 12A, inkjet recording head 14 for ejecting ink droplets 14A on cured layer 12B to form image T, and cured layer 12B And an irradiating device 18 that supplies the stimulation to be performed.

  The recording apparatus 104 includes a conveyance belt 13 that conveys the recording medium P. As the transport belt 13, for example, an endless belt described as the intermediate transfer belt 22 in the second embodiment is used. For example, the transport belt 13 is rotatably supported by three support rolls 13A while applying tension from the inner peripheral surface side. The conveyor belt 13 conveys the recording medium P sent from a storage container (not shown) or the like in the direction of the arrow by rotating.

  In the recording device 104, first, the solution supply device 12 supplies the image recording composition 12 </ b> A onto the surface of the recording medium P being conveyed by the conveyance belt 13 to form the cured layer 12 </ b> B. Next, based on predetermined image information, the ink droplets 14A are ejected by the ink jet recording head 14, and the image T is formed by applying the ink droplets 14A to the cured layer 12B formed on the recording medium P. Finally, the cured layer 12B is cured by the irradiation device 18, whereby a cured layer including the image T by the ink droplets 14A is formed on the recording medium P.

  Except for these, the aspects described in the first embodiment are applied, and thus the description thereof is omitted.

  In the recording apparatus according to any of the embodiments described above, the image recording composition 12A is applied to the intermediate transfer drum 10, the intermediate transfer belt 22, or the recording medium P to form the cured layer 12B. Then, after applying the ink droplets 14A to the cured layer 12B to form the image T (in the first to third embodiments, after being further transferred to the recording medium P), the image T was formed. The cured layer 12B is completely cured by irradiation with ultraviolet rays. At this time, the cured layer 12B is cured to become a cured layer. Therefore, regardless of whether the recording medium P is a non-penetrable medium or a permeable medium, image formation is performed on various recording media P.

  In this embodiment, since the image recording composition described above is used as the image recording composition 12A, the adhesiveness of the cured layer formed on the recording medium P to the recording medium P is determined. It is considered that the flexibility of the cured layer can be improved while maintaining the above.

  Hereinafter, an example is given and it demonstrates more concretely. However, it is not particularly limited by these examples. In the following, “part” is based on mass unless otherwise specified.

[Example 1]
-Preparation of image recording composition-
First, a mixture of the following materials was prepared.
Polyol urethane prepolymer having a bifunctional group (trade name: M1600, manufactured by Toa Gosei Co., Ltd., having an acrylate as a functional group, number average molecular weight 30000) ... 10% by mass
・ Lauryl acrylate (hydrophobic monomer (sp value 8.7)) (manufactured by Toagosei Co., Ltd.)
... 10% by mass
-TMP-3EOTAc (made by Shin-Nakamura Chemical Co., Ltd.) as other hydrophobic monomer: 40% by mass
・ Ethylene oxide ・ Propylene oxide modified ・ Trifunctional acrylic monomer (trade name: TEGO2200N (manufactured by Degussa), HLB = 11) (trifunctional acrylate UV curable monomer, surfactant) ・ ・ ・ 5% by mass

  Next, after adding 30% by mass of a mixture of aquaric CS7s (Nippon Catalyst) cross-linked sulfonic acid-modified sodium polyacrylate having a central particle size of 2.8 μm and spheronized as a liquid absorbing component, The mixture was mixed for 48 hours by stirring. Further, 5% by mass of IC184 (Ciba Specialty Chemicals) was added as a polymerization initiator to prepare an image recording composition A1.

―Preparation of ink―
・ Carbon black 5 parts ・ Styrene-acrylic acid-butyl acrylate ester 1.5 parts ・ Glycerin 25 parts ・ Diethylene glycol monobutyl ether 6 parts ・ Oxyethylene oleyl ether 0.5 parts And NaOH were added, followed by filtration through a 2 μm filter to obtain a black ink.

―Preparation of intermediate transfer member―
A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer was applied to a polyimide seamless belt having a thickness of 83 μm (centrifugal semiconductive belt manufactured by Nitto Denko Corporation) using a die coater (thickness: 33 μm) to obtain an intermediate transfer member.

  The intermediate transfer member is mounted as an intermediate transfer drum 10 on a recording apparatus having the structure shown in FIG. 1, and the image recording composition A1 prepared above is continuously applied to the intermediate transfer member with a thickness of 23 μm. A cured layer was formed. Then, a 100% solid and 2 dot thickness line image is printed on the cured layer with the black ink (resolution: 1200 × 1200 dpi, drop size: 2 pL), and then a recording medium (OK Kanto) with a weight of 1 kg. Transfer to top coat paper). Then, the cured layer on which the image was printed on the recording medium was irradiated with ultraviolet rays (160 seconds with a halogen lamp for 5 seconds) to cure the cured layer to obtain a cured layer.

<Evaluation>
The following measurements and evaluations were performed.

(Hardened layer thickness)
The thickness of the cured layer formed on the recording medium was measured. The measurement results are shown in Table 1.

(Shore D hardness of hardened layer)
The Shore D hardness of the cured layer formed on the recording medium was measured. The measurement results are shown in Table 1.
In addition, Shore D hardness of the hardened layer was performed according to the method described in JISK7215, and was performed using Shimadzu Dynamics micro hardness tester DUH-201S.

(water resistant)
The residue state of visual deformation after dropping one drop of water on the cured layer formed on the recording medium and wiping with a waste cloth after 60 seconds was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
-G1: When there is almost no dent / drop mark.
-G2: When the dent and the trace of dripping are confirmed visually.
G3: When dents and dripping marks are remarkable.

(Cross cut test)
For the cured layer formed on the recording medium, a cross-cut test is performed in accordance with JIS K5400, and it is peeled off from the recording medium with cello tape (registered trademark), and the number of debris of the cured layer remaining on the recording medium without peeling. I counted. The results are shown in Table 1.
The results of the cross cut test indicate that the larger the “remaining number” value shown in Table 1, the higher the adhesion (adhesiveness) of the cured layer to the recording medium.

(Adhesive strength)
The cured layer formed on the recording medium was subjected to a peeling test according to JIS K6301 in an environment of 22 ° C. and 55% RH, and the peeling strength from the recording medium was measured. In addition, the size of the strip-shaped test piece used in this peeling test was 25 mm in width and 90 mm in length. The tensile speed was 10 mm / min. The measurement results are shown in Table 1.

(Bending test)
The cured layer formed on the recording medium was bent at 180 ° to make a crease, and evaluated according to the following evaluation criteria.
G1: When there is no crease and there is recoverability after deformation.
G2: When the crease remains but there is no crack and the deformation remains.
G3: When cracks and deformation traces remain in the hardened layer along the crease.

(Transfer efficiency)
The transfer efficiency (%) of the cured layer to the recording medium was measured by the following method.
The mass of the intermediate transfer belt per unit area (10 × 10 cm) is measured in advance, and is obtained from the mass of the coating film when the curable solution is applied thereon, and the mass of the intermediate transfer belt after being transferred to a sheet and cured. It was. The measurement results are shown in Table 1.

(Adhesiveness)
For adhesiveness, two types of recording media are available: paper made of polyethylene terephthalate (PET) resin (trade name PETC50 manufactured by Oji Tac Co., Ltd.) and paper made of polypropylene (PP) resin (Yupo 80 manufactured by Oji Tac Co., Ltd.). For each recording medium, the adhesiveness of the cured layer to the recording medium was evaluated by the following method.
The evaluation criteria were as follows.
The transfer weight of the resin sheet after photocuring was weighed with respect to the initial coating weight, and the ratio from the weight before and after the transfer weight to the coating weight was defined as the transfer efficiency. Then, the evaluation was made according to the following evaluation criteria according to the transfer efficiency.
G1: When the transfer efficiency is 95% or more.
G2: When the transfer efficiency is 80% or more.
G3: When the transfer efficiency is less than 80%.

(Evaluation of uneven printing in the image area)
The density was measured using X-Rite 968 (manufactured by X-Rite), and the degree of occurrence of printing unevenness of the formed image was evaluated according to the following criteria.
G1: When density measurement is performed at any 10 locations (parts with different droplet ejection densities) in the image area, and the difference between the maximum density and the minimum density is 0.05 or less.
G2: When density measurement is performed at any 10 locations (parts with different droplet ejection densities) in the image area and the difference between the maximum density and the minimum density is 0.1 or less.
G3: When density measurement is performed at any 10 locations (parts with different droplet ejection densities) in the image area, and the difference between the maximum density and the minimum density exceeds 0.1.

(Evaluation of uneven density in image area)
The density unevenness of the image on the cured layer formed on the recording medium was visually confirmed. The evaluation criteria are as follows. The evaluation results are shown in Table 1.

G1: No density unevenness is observed in the highlight image.
G2: A slight unevenness in the density of the highlight image is observed, but there is no practical problem.
G3: Density unevenness of the highlight image is observed in some places, but at a level where there is no practical problem.
G4: A level in which the density unevenness of the highlight image is noticeable and becomes a problem in practical use.

[Example 2]
The urethane prepolymer (trade name: M1600) in the image recording composition A1 prepared in Example 1 is a polyester urethane prepolymer (trade name: M6100, manufactured by Toagosei Co., Ltd., having a diacrylate group as a functional group, number average. A cured layer was formed on the recording medium by the same production method as in Example 1 except that the image recording composition A2 having a molecular weight of 10,000) was prepared, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 3
The urethane prepolymer (trade name: M1600) in the image recording composition A1 prepared in Example 1 is a urethane prepolymer (trade name CN3211, manufactured by Osaka Organic Chemical Co., Ltd., having a diacrylate group as a functional group, and a number average molecular weight. In the same production method as in Example 1, except that an image recording composition A3 was prepared by adding ethylhexyl acrylate (manufactured by Daicel, trade name, sp value 9.0) as a hydrophobic monomer instead of 25000). A cured layer was formed on the medium, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 4
Instead of lauryl acrylate ((sp value 8.7) (manufactured by Toagosei Co., Ltd.)) used as the hydrophobic monomer in the image recording composition A1 prepared in Example 1, isobonyl methacrylate (manufactured by Toagosei Co., Ltd., commercial product) Name: IBXMA, sp value 9.6), except that the image recording composition A4 was prepared, a cured layer was formed on the recording medium by the same production method as in Example 1, and the same test as in Example 1 Went. The evaluation results are shown in Table 1.

Example 5
By not using the lauryl acrylate ((sp value 8.7) (manufactured by Toagosei Co., Ltd.)) used as the hydrophobic monomer in the image recording composition A1 prepared in Example 1, the composition does not contain a hydrophobic monomer. Except that the image recording composition A5 was prepared, a cured layer was formed on the recording medium by the same production method as in Example 1, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

[Comparative Example 1]
Except that the urethane prepolymer (trade name: M1600) in the image recording composition A1 prepared in Example 1 was not used, an image recording composition B1 having no urethane prepolymer was prepared. A cured layer was formed on the recording medium by the same production method as in Example 1, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 6
-Preparation of image recording composition-
First, a mixture of the following materials was prepared.
・ Polyethylene glycol urethane acrylate (trade name: EBECRY2000, manufactured by Daicel Cytec, number average molecular weight 8000, trifunctional acrylate) ・ 10 mass%
Trifunctional trimethylolpropane polypropylene oxide-modified triacrylate (trade name: M321, manufactured by Toa Gosei Co., Ltd.) 25% by mass
-As the hydrophobic monomer, ethylene oxide-modified trimethylolpropane triacrylate TMP-3EOn = 1TAc (manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 25% by mass
・ Ethylene oxide ・ Propylene oxide modified ・ Trifunctional acrylic monomer (trade name: TEGO2200N (Degussa), HLB = 11) (UV curable monomer, surfactant) ・ ・ ・ 5% by mass

  Next, after adding 30% by mass of a mixture of aquaric CS7s (Nippon Catalyst) cross-linked sulfonic acid-modified sodium polyacrylate having a central particle size of 2.8 μm and spheronized as a liquid absorbing component, The mixture was mixed for 48 hours by stirring. Further, 5% by mass of IC184 (Ciba Specialty Chemicals) was added as a polymerization initiator to prepare an image recording composition A6.

A cured layer was formed on the recording medium by the same production method as in Example 1 except that Image Recording Composition A6 was prepared as an image recording composition, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 7
Instead of the “polyethylene glycol urethane acrylate” used in the image recording composition A6 prepared in Example 6, a polypropylene-modified polyester bifunctional urethane acrylate (trade name EBCERYL270, manufactured by Daicel Cytec, number average molecular weight 1500) 10 mass A cured layer was formed on a recording medium by the same production method as in Example 1 except that the image recording composition A7 was prepared using%, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 8
Instead of the “polyethylene glycol urethane acrylate” used in the image recording composition A6 prepared in Example 6, 10% by mass of EBECRYL8804 (a polyester diacrylate manufactured by Daicel Cytec, molecular weight 1200) is used. A cured layer was formed on the recording medium by the same production method as in Example 1 except that A8 was prepared, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 9
Instead of the “polyethylene glycol urethane acrylate” used in the image recording composition A6 prepared in Example 6, 10% by mass of EBECRYL12 (a polyether urethane diacrylate molecular weight 1000 manufactured by Daicel Cytec) was used. A cured layer was formed on the recording medium by the same manufacturing method as in Example 1 except that the product A9 was prepared, and the same test as in Example 1 was performed. The evaluation results are shown in Table 1.

  As shown in Table 1, the flexibility of the cured layer was improved in the examples as compared with the comparative examples. In addition, compared with the comparative example, the adhesiveness of the cured layer to the recording medium was also improved in the examples.

DESCRIPTION OF SYMBOLS 10 Intermediate transfer drum (intermediate transfer body), 12 Solution supply apparatus, 12A Image recording composition, 12B Curing layer, 14 Inkjet recording head, 16 Transfer apparatus, 16A Pressure roll, 16B Pressure roll, 18 Irradiation apparatus, 22 intermediate transfer belt (intermediate transfer member), 24 second irradiation device, 101 recording device, 102 recording device, 103 recording device, 104 recording device

Claims (7)

An absorbent component;
UV curable monomers,
A surfactant,
A urethane prepolymer having a functional group;
A composition for image recording, comprising:   The image recording composition according to claim 1, wherein the urethane prepolymer includes a propylene oxide structure.   The image recording composition according to claim 1, wherein the urethane prepolymer contains an ethylene oxide structure.   The image recording composition according to any one of claims 1 to 3, further comprising a hydrophobic monomer having a functional group and a solubility parameter of 9.6 or less.   The image recording composition according to claim 4, wherein the hydrophobic monomer has at least one of a propylene oxide structure and a propylene oxide structure. An intermediate transfer member;
A supply device for supplying the image recording composition according to any one of claims 1 to 5 to the intermediate transfer member,
A discharge device that discharges droplets containing an aqueous solvent onto a cured layer formed by the image recording composition supplied on the intermediate transfer member;
A transfer device for transferring the cured layer to which the droplets have been discharged from the intermediate transfer member to a recording medium;
An irradiation device for irradiating the cured layer with ultraviolet rays;
Recording device. A supply device for supplying the image recording composition according to any one of claims 1 to 5 to a recording medium;
An ejection device for ejecting liquid droplets containing an aqueous solvent onto a cured layer formed of the image recording composition supplied on the recording medium;
An irradiation device for irradiating the cured layer on which the droplets are discharged with ultraviolet rays;
Recording device.

Images