JP2008188916A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device and an image recording method which suppress curing of ink at least in a nozzle by a simple means, perform inkjet discharge stably for a long term and which is effective and easy for maintenance. <P>SOLUTION: In the image recording method and the inkjet recording device for irradiating and curing the medium S to be recorded by an energy irradiating means 56 with an active energy ray by image forming by discharging an active energy ray-curable type liquid functional material from the nozzle of an inkjet head 51 based on an image signal toward the medium S to be recorded to be conveyed, before the liquid functional material is introduced into the inkjet head 51, a basic treating liquid is introduced into a nozzle inner wall, and curing of the liquid functional material on the nozzle inner wall is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet apparatus that forms an image by ejecting an active energy ray-curable liquid functional material onto a recording medium using an ink jet head.

  A liquid functional material (hereinafter also referred to as ink) that is cured by active energy rays such as ultraviolet rays and electron beams is ejected onto a recording medium using an inkjet head, and the liquid functional material is cured by energy irradiation to form an image. The inkjet apparatus to be performed has features such as being environmentally friendly, capable of being recorded at high speed on various recording media, and capable of obtaining a high-definition image that is difficult to bleed. In particular, an apparatus using ultraviolet curable ink has been developed from the viewpoint of easy handling of a light source and compactness.

However, such an ultraviolet curable ink has a characteristic that the curing is inhibited by the presence of oxygen and moisture due to the polymerization mechanism. improves. For this reason, the curability is improved by a process such as deaeration of the ink, which leads to an improvement in productivity. However, improvement in curability leads to a decrease in ink stability. That is, it becomes easy to harden. In particular, on the lower surface of the ink jet head, ink curing is likely to occur due to leakage light or reflected light from an ultraviolet light source, resulting in poor drawing. Therefore, in Patent Document 1 and Patent Document 2, reflection from each member is controlled to reduce leakage light. In addition, there is also known one that controls leakage light by an optical trap disclosed in Patent Document 3.
JP 2004-338264 A JP 2004-167968 A JP 2004-167968 A

However, it has been difficult to completely prevent irregularly reflected light from the recording medium. In particular, in a full-line type inkjet apparatus in which the recording medium always exists below the head, it is very difficult to suppress reflection from the recording medium. The leakage light control by the optical trap of Patent Document 3 also has a problem that the gap between the light source and the head is widened, so that the ejected ink spreads before being cured and the image quality is deteriorated. In addition, the apparatus described in Patent Document 3 has a drawback that the apparatus becomes large. Furthermore, when maintaining the head unit, it is necessary to remove the optical trap one by one to facilitate maintenance, and to reattach it after the maintenance is completed, and this operation requires precise adjustment of the distance from the recording medium. So a skilled worker was required.
Thus, conventionally, there has been no effective means for suppressing ink curing by a simple method and stably performing ink jet ejection for a long time.

  Accordingly, the present invention has been made to solve these problems, and an ink jet recording apparatus and an image forming apparatus that are effective and easy to maintain for performing ink jet ejection stably for a long period of time by suppressing ink curing with simple means. It aims to provide a method.

The above object is achieved by the following configuration.
(1) A head unit that collectively holds an inkjet head that discharges an active energy ray-curable liquid functional material from a nozzle based on an image signal toward a recording medium to be transported, and an active energy ray is applied to the recording medium. In an inkjet recording apparatus having energy irradiation means,
An inkjet apparatus comprising basic processing liquid supply means for supplying a basic processing liquid to at least the nozzles of the inkjet head.

  As described above, the basic treatment liquid supply means for supplying the basic treatment liquid to the nozzles of the inkjet head allows the basic treatment liquid to adhere to at least the nozzle inner wall before the liquid functional material is introduced into the inkjet head. Can be made. Since the basic treatment liquid inhibits the curing of the liquid functional material, the liquid functional material is prevented from being cured and adhered to the inner wall of the nozzle. Therefore, it is effective against leakage light, and ink jet discharge can be stably performed for a long time. Furthermore, there is no need to remove the light shielding member during maintenance, and fine adjustment of the alignment does not occur.

(2) The ink jet apparatus according to (1), wherein the basic processing liquid supply means includes means for introducing a basic processing liquid into the liquid functional material supply path upstream of the head unit.

  As described above, the basic processing liquid supply means includes means for introducing the basic processing liquid into the liquid functional material supply path upstream of the head unit, so that the base can be spread over the entire flow path in the head unit. The functional treatment liquid can be adhered, and the curing of the liquid functional material can be inhibited. Such a process can be carried out for each maintenance in which all the liquid functional material in the head unit is discharged, and it becomes possible to stably perform inkjet discharge over a longer period of time.

(3) The inkjet apparatus according to (1), wherein the basic processing liquid supply unit includes an injection unit that injects a basic processing liquid from a nozzle of the inkjet head.

  As described above, the basic processing liquid supply means includes the injection means for injecting the basic processing liquid from the nozzle of the inkjet head, so that the basic processing liquid can be attached at least in the nozzle portion. , The curing of the liquid functional material can be inhibited. In this case, even if the liquid functional material is introduced into the head unit, the basic treatment liquid can be injected, and the timing of introduction of the basic treatment liquid can be arbitrarily selected. Moreover, it is possible to adhere the basic treatment liquid to the surface where the nozzle is opened, and it is possible to more reliably suppress the curing adhesion of the liquid functional material.

(4) The ink jet apparatus according to any one of (1) to (3), wherein the basic treatment liquid contains a basic organometallic compound and an ether compound.

  By using such a basic compound, curing adhesion of the liquid functional material can be more reliably suppressed.

(5) An active energy ray-curable liquid functional material is ejected from a nozzle of an inkjet head based on an image signal toward a recording medium to be conveyed to form an image, and the active energy is applied to the recording medium by active energy ray irradiation means. In the image recording method of radiation curing the line,
An image recording method in which a basic processing liquid is introduced at least into the inner wall of the nozzle before the liquid functional material is introduced into the inkjet head.

  By doing so, the basic treatment liquid adheres at least on the inner wall of the nozzle before the liquid functional material is introduced into the inkjet head. Since the basic treatment liquid inhibits the curing of the liquid functional material, the liquid functional material is prevented from being cured and adhered to the inner wall of the nozzle. Therefore, it is effective against leakage light, and ink jet discharge can be performed stably for a long time.

(6) The image recording method according to (5), wherein the introduction of the basic treatment liquid is after the discharge of the liquid functional material in the inkjet head.
As described above, the basic functional liquid is introduced into the ink-jet head after the liquid functional material in the ink-jet head is discharged by maintenance or the like. Then, the basic treatment liquid can be adhered over the entire flow path in the inkjet head, and the curing of the liquid functional material can be inhibited. And since such a process is implemented for every maintenance, it becomes possible to perform inkjet discharge stably over a longer time.

(7) The image recording method according to (5), wherein the introduction of the basic treatment liquid is before the liquid functional material is first introduced into the inkjet head.

  As described above, the basic treatment liquid is introduced into the ink jet head before the liquid functional material is first introduced into the ink jet head. Then, since the basic treatment liquid is attached to at least the inner wall of the nozzle from the start of use of the ink jet head, and even after the liquid functional material is introduced, it is after the formation of the curing inhibition state, so the liquid at the nozzle position Curing of the functional material can be prevented from the beginning, and inkjet discharge can be stably performed over a long period of time.

  With the above configuration, it is possible to obtain an effective image recording method and ink jet recording apparatus that suppresses the curing of the liquid functional material at least on the inner wall of the nozzle and stably performs ink jet ejection for a long period from the start of use of the ink jet head. It will be. Moreover, it is not necessary to remove the light shielding member or the like for maintenance, and fine adjustment of the fixed position is also unnecessary.

Hereinafter, the present invention will be described in detail based on examples.
FIG. 1 is a configuration diagram of an active energy ray curable inkjet recording apparatus targeted by the present invention.
The active energy ray curable ink jet recording apparatus uses, as the active energy ray curable ink, a UV curable ink that is cured by irradiation with ultraviolet rays.

  In FIG. 1, in the case 22 of the active energy ray-curable inkjet recording apparatus 10, the recording medium S wound around the delivery-side roll 44 a is extended by the conveyance roller 130 and passes through the flexible light shielding door 14. Then, it is conveyed into the housing 12. The transported recording medium S is sent out from the flexible light shielding door 16 disposed on the opposite side of the housing 12 and wound around the winding-side roll 44b.

  The recording medium S carried into the housing 12 is held by the conveyance holding roller 45 a and is sent onto the plurality of support conveyance rollers 46. Further, the recording medium S is held by a conveyance holding roller 45 b disposed on the downstream side of the support conveyance roller 46, scanned and conveyed on the support conveyance roller 46, and sent out from the light shielding door 16. On the support conveyance roller 46, the image recording unit 50 is arranged at a position opposite to the recording medium S. In this way, the scanning conveyance unit 40 is formed by the delivery side roll 44 a, the winding side roll 44 b, the conveyance roller 130, the conveyance holding rollers 45 a and 45 b, and the support conveyance roller 46.

  The image recording unit 50 performs inkjet image recording and active energy ray (ultraviolet light in this embodiment) irradiation fixing on the recording medium S being scanned and conveyed on the support conveyance roller 46. Among them, an ink storage unit 80 (shown in FIG. 2) that supplies and stores ink to the head 51 of the image recording unit 50 through a supply path 53 is provided at an appropriate position in the housing 22. The ink jet head 51 of the head unit 52 is provided with the tip of the ink discharge section facing the transport surface of the support transport roller 46 at the image recording position, and the head unit 52 determines the length of the recording medium S in the width direction. It is a full line type head and adopts a piezo type head. Further, the head unit 52 ejects ink curable by active energy rays toward the recording medium S. The head unit 52 is connected to a head driver 54 which is an inkjet head driving device, and controls the ejection amount of each ink color. A coating mechanism other than inkjet or a surface treatment mechanism such as corona treatment may be provided around the image recording unit 50.

  An active energy ray irradiation unit 56 is disposed downstream of the inkjet head 51. A set of the inkjet head 51 and the active energy ray irradiation unit 56 is held and arranged on the head holder in the downstream direction by the number of inks (six sets in the figure) to form the head unit 52. The image recording unit 50 is connected to an ink supply unit (not shown) for supplying ink. In FIG. 1, the active energy ray irradiating units 56 are provided by the number of the head units 52, but it is not necessary to provide the irradiating units for each inkjet head, and an arbitrary number can be provided. Further, the type, light amount, and spectrum of each active energy ray irradiation unit may be different.

Next, the present invention will be described based on the vicinity of the head unit.
FIG. 2 is a schematic view of the vicinity of the head unit of the ink jet apparatus according to the first embodiment of the present invention.
In FIG. 2, in the image recording unit 50, in the supply path 53 to the inkjet head 51, a switching valve 61 is arranged for each head at an upstream position immediately before the inkjet head 51 corresponding to each color, and a basic processing liquid supply path. 63 is connected. The basic processing liquid supply path 63 is connected to a basic processing liquid supply unit 60 disposed at an appropriate position in the housing 22. The basic processing liquid supply unit 60 also includes a basic processing liquid storage tank.

  In the above-described image recording, first, when the head unit 52 is used for the first time, before the ink is introduced into each inkjet head 51, the switching valve 61 is set to the basic processing liquid supply unit 60 side, and each inkjet The basic processing liquid is introduced into the head 51 through the basic processing liquid supply path 63. The basic treatment liquid passes through each inkjet head 51 and is discharged from the nozzle. The discharged liquid is recovered by appropriate recovery (not shown). The basic treatment liquid may be stored in the ink jet head 51, but normally it is not necessary to store it, and it is sufficient to discharge it.

  In this state, when the switching valve 61 is switched to the supply path 53 side and each color ink is introduced into each inkjet head 51, the basic processing liquid remains at least on the nozzle inner wall surface of the inkjet head 51, and the liquid functionality It inhibits the curing of the material and suppresses the liquid functional material from being cured and adhered to the inner wall of the nozzle. Accordingly, it is effective against leakage light, and ink jet discharge can be performed stably.

  Next, the basic processing liquid supply unit 60 can be configured to monitor the status of ink ejection control of the head driver 54. The head unit 52 may discharge all ink from each inkjet head 51 mainly for maintenance. When such a state is monitored by the basic processing liquid supply unit 60, when all of the ink has been completely discharged, the switching valve 61 is switched to the basic processing liquid supply unit 60 side, and the basic processing liquid supply path to each inkjet head 51. A basic treatment solution is introduced through 63. Thereafter, the same treatment as in the case of introducing the basic treatment solution for the first time is performed.

As described above, by introducing the basic processing liquid into the ink jet head in the case of maintenance or the like, the basic processing liquid is adhered over the entire flow path in the ink jet head. Therefore, the curing of the liquid functional material can be inhibited, and since such a process is performed for each maintenance, it is possible to stably perform ink jet ejection for a longer time.
Further, it is not necessary to disassemble the parts of each part at the time of maintenance, so that simplification of the apparatus and ease of operation / maintenance can be obtained.

FIG. 3 is a partial schematic view of the vicinity of the head unit of the ink jet apparatus according to the second embodiment of the present invention.
In FIG. 3, the inkjet head 51 is sandwiched between holders 55. A basic treatment liquid injection unit 71 that covers the ink discharge side 57 of the inkjet head 51 and can be brought into close contact with the holder 55 is provided. The basic processing liquid injection unit 71 is disposed at a position outside the conveyance range of the recording medium S during image formation, and the maintenance of the inkjet head 51 is performed by a moving mechanism (not shown) in a state where the entire apparatus is turned off. The ink is moved to a position covering the ink discharge side 57 and is placed in close contact with the holder 55.

  In the above-described image recording, when an image is formed by the image recording unit 50, the image recording unit 50 is moved to a position outside the transport range of the recording medium S as described above. The moving means of the basic processing liquid injection unit 71 can be configured to be electrically connected to the control unit of the ink jet device and the image recording unit 50, whereby the use of the ink jet device can be started, maintained, It detects the timing such as at rest or when the power is turned off, and moves to the ink ejection side 57 position. This can also be a manual configuration.

  When the close contact with the inkjet head 51 is completed, the basic processing liquid injection unit 71 is connected to the injection path 72 from the basic processing liquid supply unit 60 and the like, and presses the basic processing liquid toward the ink discharge side 57. To do. Accordingly, the basic processing liquid enters at least the nozzle of the inkjet head 51 and adheres to the inner wall of the nozzle and the ink discharge surface. The injection state may be maintained as it is, or the process may be terminated at an arbitrary time interval.

Therefore, at least at the nozzle portion, the basic treatment liquid can be adhered, and the curing of the liquid functional material can be inhibited. In this case, even if the liquid functional material is introduced into the head 51, the basic treatment liquid can be injected, and the timing of introduction of the basic treatment liquid can be arbitrarily selected. Moreover, it is possible to adhere the basic treatment liquid to the surface where the nozzle is opened, and it is possible to more reliably suppress the curing adhesion of the liquid functional material.
Further, it is not necessary to disassemble the parts of each part at the time of maintenance, so that simplification of the apparatus and ease of operation / maintenance can be obtained.

The conditions for the basic treatment liquid include the following combinations of basic organometallic compounds and ether compounds.
(Basic organometallic compounds)
3-aminopropyltriethoxysilyl, 3-aminopropyltrimethoxysilyl, 3-dimethylaminopropyltriethoxysilyl, 3-dimethylaminopropyltrimethoxysilyl, 2-aminoethyltriethoxysilyl, 2-aminoethyltrimethoxysilyl, 2-dimethylaminoethyltriethoxysilyl, 2-dimethylaminoethyltrimethoxysilyl, 4-aminophenyltriethoxysilyl, 4-dimethylaminophenyltriethoxysilyl, 3-dimethylaminopropyltriethoxyzirconyl, 3-dimethylaminopropyltri The addition amount of ethoxy titanyl basic organometallic compound is 1 to 60 wt%, preferably 5 to 55 wt%, and more preferably 10 to 50 wt%.
(Ether compound)
Examples of the ether compound that can be used in the present invention include monoethers to ethers composed of polyols such as glycol, triol, and tetraol.
Examples of glycol ethers include compounds represented by the following general formula [I] or [II]. However, it is not limited to these.
[I] R1O- (CH2CH (R2) -O) m-R3
[II] R4O- (CH2CH2-O) p-CO-CH3
In the formula, R1 to R4 are independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a benzyl group, a phenyl group, a phenyl group, an allyl group, an acrylic group, a methacryl group, or a cyclic alkyl group having 5 to 10 carbon atoms. M and p represent an integer of 1-20. Specific examples include triethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol diacrylate, diethylene glycol diacrylate, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, ethylene Glycol monoethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, diethylene glycol diethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, trie Lenglycol monobutyl ether, diethylene glycol dibutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monobenzyl ether, diethylene glycol monobenzyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, propylene glycol Monoethyl ether, Dipropylene glycol monoethyl ether, Tripropylene glycol monoethyl ether, Dipropylene glycol diethyl ether, Tripropylene glycol divinyl ether, Dipropylene glycol divinyl ether, Tripropylene glycol diacrylate, Dipropi Glycol diacrylate and the like.
Examples thereof include polyethylene glycol and polypropylene glycol having a molecular weight of 200 to 1000, monomethyl ether, monoethyl ether, monopropyl ether, isopropyl ether, monobutyl ether and the like of these compounds.
Basically, it can be composed of 70% by weight of tripropylene glycol monomethyl ether and 30% by weight of 3-dimethylaminotrimethoxysilane.

  Here, the “active energy ray” as used in the present invention is not particularly limited as long as it can impart energy capable of generating a starting species in the ink composition by irradiation, and is widely expressed as α-ray. , Γ rays, X rays, ultraviolet rays, visible rays, electron beams, and the like. Among these, from the viewpoints of curing sensitivity and device availability, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable. Therefore, the ink composition of the present invention is preferably an ink composition that can be cured by irradiation with ultraviolet rays.

In the inkjet recording apparatus of the present invention, the peak wavelength of the active energy ray is, for example, 200 to 600 nm, preferably 300 to 450 nm, more preferably 350, although it depends on the absorption characteristics of the sensitizing dye in the ink composition. It is suitable that it is ˜450 nm. The (a) electron transfer type initiation system of the ink composition of the present invention has sufficient sensitivity even with a low-power active energy ray. Therefore, the output of the active energy ray is, for example, 2,000 mJ / cm ² or less, preferably 10 to 2,000 mJ / cm ² , more preferably 20 to 1,000 mJ / cm ² , and still more preferably 50 to An irradiation energy of 800 mJ / cm ² is appropriate. The active energy ray exposure surface illuminance (the maximum illuminance of the surface of the recording medium) is, for example, 10 to 2,000 mW / cm ^2, preferably, suitably be irradiated at 20 to 1,000 mW / cm ² It is.
In particular, in the ink jet recording apparatus of the present invention, the active energy ray irradiation is performed with ultraviolet rays having an emission wavelength peak of 390 to 420 nm and a maximum illuminance on the recording medium surface of 10 to 1,000 mW / cm ^2. Irradiation is preferably from a generated light emitting diode.

In the ink jet recording apparatus of the present invention, the active energy ray may be applied to the ink composition ejected on the recording medium, for example, for 0.01 to 120 seconds, preferably 0.1 to 90 seconds. Is appropriate.
Furthermore, in the ink jet recording apparatus of the present invention, the ink composition is heated to a constant temperature, and the time from the landing of the ink composition on the recording medium to the irradiation of the active energy ray is set to 0.01 to 0.5. It is desirable to set it to seconds, preferably 0.02 to 0.3 seconds, and more preferably 0.03 to 0.15 seconds. Thus, by controlling the time from the landing of the ink composition to the recording medium to the irradiation of the active energy ray to an extremely short time, it is possible to prevent the landed ink composition from bleeding before curing. Become.

  In order to obtain a color image using the ink jet recording apparatus of the present invention, it is preferable to superimpose in order from the color with the lowest brightness. By overlapping in this manner, the active energy rays can easily reach the lower ink, and good curing sensitivity, reduction of residual monomers, reduction of odor, and improvement of adhesion can be expected. In addition, although irradiation with active energy rays can be performed by injecting all colors and exposing them together, exposure for each color is preferable from the viewpoint of curing acceleration.

  Further, as described above, the active energy ray-curable ink such as the ink composition of the present invention desirably has a constant temperature in the ejected ink composition. It is preferable to perform temperature control by heat insulation and heating. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

  In addition, mercury lamps, gas / solid lasers, and the like are mainly used as active energy ray sources, and mercury lamps and metal halide lamps are widely known as ultraviolet light curable ink jets. Furthermore, replacement with a GaN-based semiconductor ultraviolet light emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as radiation sources for active energy ray-curable inkjets.

  Further, as described above, a light emitting diode (LED) and a laser diode (LD) can be used as the active energy ray source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. Furthermore, when shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can emit active energy rays centered between 300 nm and 370 nm. . Other ultraviolet LEDs are also available and can radiate radiation in different ultraviolet bands. A particularly preferable active energy ray source in the present invention is a UV-LED, and a UV-LED having a peak wavelength of 350 to 420 nm is particularly preferable.

[Recording medium]
The recording medium to which the ink composition of the present invention can be applied is not particularly limited, and various kinds of non-absorbing resin materials used for ordinary non-coated paper, coated paper, so-called soft packaging, or the like. A resin film formed into a film can be used, and examples of the various plastic films include PET film, OPS film, OPP film, ONy film, PVC film, PE film, and TAC film. In addition, examples of the plastic that can be used as a recording medium material include polycarbonate, acrylic resin, ABS, polyacetal, PVA, and rubbers. Metals and glasses can also be used as the recording medium.
In the ink composition of the present invention, when a material with low thermal shrinkage at the time of curing is selected, the adhesive property between the cured ink composition and the recording medium is excellent. Films that tend to curl and deform, such as heat-shrinkable PET film, OPS film, OPP film, ONy film, PVC film, etc., have the advantage that a high-definition image can be formed.

Below, each component used for the ink composition which can be used by this invention is demonstrated sequentially.
[Ink composition]
The ink composition used in the present invention is an ink composition that can be cured by irradiation with active energy rays, and includes a cationic polymerization-based ink composition in which curing inhibition occurs due to a basic compound. These compositions will be described in detail below.

(Cationically-polymerized ink composition)
The cationic polymerization ink composition contains (a) a cationic polymerizable compound and (b) a compound that generates an acid upon irradiation with active energy rays. If desired, it may further contain a colorant, an ultraviolet absorber, a sensitizer, an antioxidant, an antifading agent, a conductive salt, a solvent, a polymer compound, a surfactant, and the like.
Hereafter, each component used for a cationic polymerization type ink composition is demonstrated one by one.

[(A) Cationic polymerizable compound]
The (a) cationic polymerizable compound used in the present invention is not particularly limited as long as it is a compound that causes a polymerization reaction by an acid generated from a compound that generates an acid upon irradiation with an active energy ray described later and cures. In addition, various known cationic polymerizable monomers known as photo cationic polymerizable monomers can be used. Examples of the cationic polymerizable monomer include various publications such as 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-2001-220526. Examples thereof include epoxy compounds, vinyl ether compounds, oxetane compounds and the like.

Examples of the epoxy compound include aromatic epoxides, alicyclic epoxides, and aliphatic epoxides.
Aromatic epoxides include di- or polyglycidyl ethers produced by the reaction of polyphenols having at least one aromatic nucleus or their alkylene oxide adducts and epichlorohydrin, such as bisphenol A or its alkylene oxides. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or its alkylene oxide adducts, and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned preferably.

  Examples of the aliphatic epoxide include dihydric polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. Typical examples include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, di- or tri- or di- or tri-glycol or adducts thereof. Polyglycidyl ether of polyhydric alcohol such as glycidyl ether, diglycidyl ether of polyethylene glycol or alkylene oxide adduct thereof, diglycidyl ether of polyalkylene glycol represented by diglycidyl ether of polypropylene glycol or alkylene oxide adduct thereof, etc. Can be mentioned. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

The epoxy compound may be monofunctional or polyfunctional.
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-epoxy Hexylmethyl) 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) ), Dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 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 -Diepoxyoctane, 1,2,5,6-diepoxycyclooctane and the like.

  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 the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

The vinyl ether compound may be monofunctional or polyfunctional.
Specifically, examples of monofunctional vinyl ethers 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 , Methoxypolyethyleneglycol 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 can be arbitrarily selected and used as described in JP-A Nos. 2001-220526, 2001-310937, and 2003-341217. .
The compound having an oxetane ring that can be used in the ink composition of 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 within a good handling range, and obtain high adhesion between the cured ink composition and the recording medium. Can do.

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 herein 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 one oxetane ring from the viewpoint of the viscosity and tackiness of the ink composition.

In the ink composition of the present invention, these cationic polymerizable compounds may be used alone or in combination of two or more, but from the viewpoint of effectively suppressing shrinkage during ink curing. Is preferably a combination of at least one compound selected from an oxetane compound and an epoxy compound and a vinyl ether compound.
The content of the (a) cationic polymerizable compound in the ink composition is suitably 10 to 95% by mass, preferably 30 to 90% by mass, and more preferably 50 to 85%, based on the total solid content of the composition. It is the range of mass%.

[(B) Compound generating acid upon irradiation with active energy ray]
The ink composition of the present invention contains a compound that generates an acid upon irradiation with active energy rays (hereinafter, appropriately referred to as a “photoacid generator”).
Examples of the photoacid generator that can be used in the present invention include photoinitiators for photocationic polymerization, photoinitiators for photoradical polymerization, photodecolorants for dyes, photochromic agents, and light used for microresists. (400-200 nm ultraviolet rays, far ultraviolet rays, particularly preferably g-line, h-line, i-line, KrF excimer laser beam), ArF excimer laser beam, electron beam, X-ray, molecular beam, ion beam, etc. A compound capable of generating can be appropriately selected and used.

  Examples of such photoacid generators include onium salts such as diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts that decompose to generate an acid upon irradiation with active energy rays. , Organic halogen compounds, organic metal / organic halides, photoacid generators having an o-nitrobenzyl-type protecting group, compounds that generate sulfonic acids by photolysis, such as iminosulfonates, disulfone compounds, diazo Examples thereof include ketosulfone and diazodisulfone compounds.

  As the photoacid generator, oxazole derivatives and s-triazine derivatives described in JP-A No. 2002-122994, paragraphs [0029] to [0030] are also preferably used. Furthermore, onium salt compounds and sulfonate compounds exemplified in JP-A No. 2002-122994, paragraph numbers [0037] to [0063] can also be suitably used as the photoacid generator in the present invention.

(B) A photo-acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the (b) photoacid generator in the ink composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, and still more preferably in terms of the total solid content of the ink composition. Is 1-7 mass%.

[Colorant]
The ink composition of the present invention can form a visible image by adding a colorant. For example, when forming an image area of a lithographic printing plate, it is not always necessary to add it, but it is also preferable to use a colorant from the viewpoint of plate inspection of the obtained lithographic printing plate.
There is no restriction | limiting in particular in the coloring agent which can be used here, According to a use, well-known various color materials and (pigment, dye) can be selected suitably, and can be used. For example, when forming an image excellent in weather resistance, a pigment is preferable. As the dye, both water-soluble dyes and oil-soluble dyes can be used, but oil-soluble dyes are preferred.

[Pigment]
The pigment preferably used in the present invention will be described.
The pigment is not particularly limited, and all commercially available organic and inorganic pigments or pigments dispersed in an insoluble resin or the like as a dispersion medium, or the resin is grafted onto the pigment surface Can be used. Moreover, what dye | stained the resin particle with dye can be used.
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 pigment, for example, a dispersion 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.
It is also possible to add a dispersant when dispersing the pigment. Examples of the dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a high molecular weight unsaturated acid ester, a high molecular weight copolymer, a modified polyacrylate, an aliphatic Examples thereof include polyvalent carboxylic acids, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate esters, and pigment derivatives. It is also preferable to use a commercially available polymer dispersant such as the Solsperse series from Zeneca.
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.

  In the ink composition, as a dispersion medium for various components such as pigments, a solvent may be added, or the solvent-free low molecular weight component (a) cationic polymerizable compound may be used as a dispersion medium. However, the ink composition of the present invention is an active energy ray curable ink, and is preferably solventless in order to cure the ink after it is applied to a recording medium. This is because if the solvent remains in the cured ink image, the solvent resistance is deteriorated or a VOC (Volatile Organic Compound) problem of the remaining solvent occurs. From such a viewpoint, as the dispersion medium, (a) a cation polymerizable compound is used, and among them, it is preferable to select a cation polymerizable monomer having the lowest viscosity in terms of dispersion suitability and handling property of the ink composition. .

The average particle size of the pigment is preferably 0.02 to 4 μm, more preferably 0.02 to 2 μm, and more preferably 0.02 to 1.0 μm.
The selection of pigment, dispersant, dispersion medium, dispersion conditions, and filtration conditions are set so that the average particle diameter of the pigment particles is within the above-mentioned preferable range. By controlling the particle size, clogging of the head nozzle can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

〔dye〕
The dye used in the present invention is preferably oil-soluble. Specifically, it means that the solubility in water at 25 ° C. (the mass of the dye dissolved in 100 g of water) is 1 g or less, preferably 0.5 g or less, more preferably 0.1 g or less. Therefore, a so-called water-insoluble oil-soluble dye is preferably used.

The dye used in the present invention preferably has an oil-solubilizing group introduced into the above-described dye mother core in order to dissolve the necessary amount in the ink composition.
As the oil-solubilizing group, long chain, branched alkyl group, long chain, branched alkoxy group, long chain, branched alkylthio group, long chain, branched alkylsulfonyl group, long chain, branched acyloxy group, long chain, branched alkoxycarbonyl group, Long chain, branched acyl group, long chain, branched acylamino group long chain, branched alkylsulfonylamino group, long chain, branched alkylaminosulfonyl group and these long chains, aryl groups containing branched substituents, aryloxy groups, aryloxycarbonyl Group, arylcarbonyloxy group, arylaminocarbonyl group, arylaminosulfonyl group, arylsulfonylamino group and the like.
In addition, for water-soluble dyes having carboxylic acid and sulfonic acid, long chain, branched alcohol, amine, phenol, aniline derivatives are used as oil-solubilizing alkoxycarbonyl groups, aryloxycarbonyl groups, alkylaminosulfonyl groups, A dye may be obtained by conversion to an arylaminosulfonyl group.

The oil-soluble dye preferably has a melting point of 200 ° C. or lower, more preferably has a melting point of 150 ° C. or lower, and still more preferably has a melting point of 100 ° C. or lower. By using an oil-soluble dye having a low melting point, the precipitation of dye crystals in the ink composition is suppressed, and the storage stability of the ink composition is improved.
Further, it is desirable that the oxidation potential is noble (high) in order to improve fading, particularly resistance to oxidizing substances such as ozone and curing characteristics. For this reason, as the oil-soluble dye used in the present invention, those having an oxidation potential of 1.0 V (vs SCE) or more are preferably used. The oxidation potential is preferably higher, the oxidation potential is more preferably 1.1 V (vs SCE) or more, and particularly preferably 1.15 V (vs SCE) or more.

As the yellow dye, a compound having a structure represented by the general formula (Y-I) described in JP-A No. 2004-250483 is preferable.
Particularly preferred dyes are dyes represented by the general formulas (Y-II) to (Y-IV) described in paragraph [0034] of JP-A No. 2004-250483. And the compounds described in paragraph numbers [0060] to [0071] of JP-A-250483. The oil-soluble dye of the general formula (Y-I) described in the publication may be used not only for yellow but also for inks of any color such as black ink and red ink.

The magenta dye is preferably a compound having a structure represented by the general formulas (3) and (4) described in JP-A No. 2002-114930. Specific examples include paragraphs of JP-A No. 2002-114930. Examples include the compounds described in [0054] to [0073].
Particularly preferred dyes are azo dyes represented by the general formulas (M-1) to (M-2) described in paragraph numbers [0084] to [0122] of JP-A No. 2002-121414, and specific examples Examples thereof include compounds described in paragraph numbers [0123] to [0132] of JP-A No. 2002-121414. The oil-soluble dyes represented by the general formulas (3), (4) and (M-1) to (M-2) described in the publication are used not only for magenta but also for any color ink such as black ink and red ink. May be.

Examples of cyan dyes include dyes represented by formulas (I) to (IV) described in JP-A No. 2001-181547, and paragraphs [0063] to [0078] of JP-A No. 2002-121414. The dyes represented by the general formulas (IV-1) to (IV-4) are mentioned as preferable examples, and specific examples include paragraph numbers [0052] to [0066] of JP-A No. 2001-181547. Examples thereof include the compounds described in paragraph Nos. [0079] to [0081] of Kai 2002-121414.
Particularly preferred dyes are phthalocyanine dyes represented by general formulas (CI) and (C-II) described in paragraphs [0133] to [0196] of JP-A No. 2002-121414, A phthalocyanine dye represented by formula (C-II) is preferred. Specific examples thereof include the compounds described in JP-A No. 2002-121414, paragraph numbers [0198] to [0201]. The oil-soluble dyes of the formulas (I) to (IV), (IV-1) to (IV-4), (CI) and (C-II) are not only cyan but also black ink or green ink. The ink may be used for any color ink.

These colorants are preferably added in an amount of 1 to 20% by mass in terms of solid content in the ink composition, and more preferably 2 to 10% by mass.
In the ink composition of the present invention, various additives can be used in combination with the essential components according to the purpose. These optional components will be described.

[Ultraviolet absorber]
In the present invention, an ultraviolet absorber can be used from the viewpoint of improving the weather resistance of the obtained image and preventing discoloration.
Examples of the ultraviolet absorber are described in JP-A-58-185679, JP-A-61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Benzotriazole compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194843, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492 and 56-21141 Cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368, JP-A-10-182621, JP The triazine compounds described in JP-A-8-501291, Research Disclosure No. Examples thereof include compounds described in No. 24239, compounds that emit ultraviolet light by absorbing ultraviolet rays typified by stilbene and benzoxazole compounds, so-called fluorescent brighteners, and the like.
The addition amount is appropriately selected according to the purpose, but is generally about 0.5 to 15% by mass in terms of solid content.

[Sensitizer]
A sensitizer may be added to the ink composition of the present invention as necessary for the purpose of improving the acid generation efficiency of the photoacid generator and increasing the photosensitive wavelength. Any sensitizer may be used as long as the photoacid generator is sensitized by an electron transfer mechanism or an energy transfer mechanism. Preferably, aromatic polycondensed compounds such as anthracene, 9,10-dialkoxyanthracene, pyrene and perylene, aromatic ketone compounds such as acetophenone, benzophenone, thioxanthone and Michlerketone, heterocyclic compounds such as phenothiazine and N-aryloxazolidinone Is mentioned. The addition amount is appropriately selected according to the purpose, but is generally 0.01 to 1 mol%, preferably 0.1 to 0.5 mol%, based on the photoacid generator.

〔Antioxidant〕
An antioxidant can be added to improve the stability of the ink composition. Examples of the antioxidant include European published patents, 223739, 309401, 309402, 310551, 310552, 359416, and 3435443. JP, 54-85535, 62-262417, 63-113536, 63-163351, JP-A-2-262654, JP-A-2-71262, Examples thereof include those described in Kaihei 3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Anti-fading agent]
In the ink composition of the present invention, various organic and metal complex anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of the metal complex anti-fading agent include nickel complexes and zinc complexes. No. 17643, VII, I to J, No. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544 at page 527, ibid. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used. .
The addition amount is appropriately selected according to the purpose, but is generally about 0.1 to 8% by mass in terms of solid content.

[Conductive salts]
Conductive salts such as potassium thiocyanate, lithium nitrate, ammonium thiocyanate, and dimethylamine hydrochloride can be added to the ink composition of the present invention for the purpose of controlling ejection properties.

〔solvent〕
In order to improve the adhesion to the recording medium, it is also effective to add a very small amount of an organic solvent to the ink composition of the present invention.
Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, and diethyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, and tert-butanol, and chlorine such as chloroform and methylene chloride. Solvents, aromatic solvents such as benzene and toluene, ester solvents such as ethyl acetate, butyl acetate and isopropyl acetate, ether solvents such as diethyl ether, tetrahydrofuran and dioxane, glycols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether And ether solvents.
In this case, it is effective to add the solvent within a range that does not cause the problem of solvent resistance and VOC, and the amount is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the whole ink composition. % Range.

[Polymer compound]
Various polymer compounds can be added to the ink composition of the present invention in order to adjust film physical properties. High molecular 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. Of these, vinyl copolymer obtained by copolymerization of acrylic monomers is preferred. Furthermore, a copolymer containing “carboxyl group-containing monomer”, “methacrylic acid alkyl ester”, or “acrylic acid alkyl ester” as a structural unit is also preferably used as the copolymer composition of the polymer binder.

[Surfactant]
A surfactant may be added to the ink composition of the present invention.
Examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457. For example, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene blocks Nonionic surfactants such as copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. An organic fluoro compound may be used in place of the 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 addition to this, if necessary, for example, leveling additives, matting agents, waxes for adjusting film physical properties, polymerization to inhibit the adhesion to recording media such as polyolefin and PET, and the like, The tackifier which does not do can be contained.
As the tackifier, specifically, a high molecular weight adhesive polymer described in JP-A-2001-49200, 5-6p (for example, (meth) acrylic acid and an alkyl group having 1 to 20 carbon atoms). An ester with an alcohol having, an ester of (meth) acrylic acid with an alicyclic alcohol having 3 to 14 carbon atoms, a copolymer comprising an ester of (meth) acrylic acid with an aromatic alcohol having 6 to 14 carbon atoms) And a low molecular weight tackifying resin having a polymerizable unsaturated bond.
[Preferred physical properties of ink composition]
The ink composition of the present invention preferably has an ink viscosity of 20 mPa · s or less, more preferably 10 mPa · s or less at the temperature at the time of ejection in consideration of ejection properties. It is preferable to adjust and determine the composition ratio.

  The common surface tension of the ink composition of the present invention is preferably 20 to 40 mN / m, more preferably 25 to 35 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and uncoated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and the wettability is preferably 40 mN / m or less.

The ink composition of the present invention thus adjusted is suitably used as an ink for inkjet recording. When used as an ink for ink jet recording, the ink composition is ejected onto a recording medium by an ink jet printer, and then the ejected ink composition is cured by irradiation with active energy rays to perform recording.
In the printed matter obtained with this ink, the image portion is cured by irradiation with active energy rays such as ultraviolet rays, and the strength of the image portion is excellent. Therefore, in addition to image formation with ink, for example, an ink receiving layer of a lithographic printing plate It can be used for various purposes such as formation of (image part).

1 is a configuration diagram of an active energy ray curable inkjet recording apparatus targeted by the present invention. FIG. FIG. 2 is a schematic view of the vicinity of a head unit of the inkjet device according to the first embodiment of the present invention. FIG. 6 is a partial schematic view of the vicinity of a head unit of an inkjet device according to a second embodiment of the present invention.

Explanation of symbols

10 Inkjet recording device 40 Scanning conveyance section (conveyance means)
50 Image recording unit 51 Full line type inkjet head 57 Nozzle side 60 Basic processing liquid supply unit 61 Switching valve 71 Basic processing liquid injection unit S is a recording medium

Claims (7)

A head unit that collectively holds an inkjet head that discharges an active energy ray-curable liquid functional material from a nozzle based on an image signal toward a recording medium to be conveyed, and an active energy ray that irradiates the recording medium with the active energy ray In an inkjet recording apparatus having irradiation means,
An inkjet apparatus comprising basic processing liquid supply means for supplying a basic processing liquid to at least the nozzles of the inkjet head.   The ink jet apparatus according to claim 1, wherein the basic processing liquid supply means includes means for introducing a basic processing liquid into a liquid functional material supply path upstream of the head unit.   The inkjet apparatus according to claim 1, wherein the basic processing liquid supply unit includes an injection unit that injects a basic processing liquid from a nozzle of the inkjet head.   The inkjet apparatus according to any one of claims 1 to 3, wherein the basic treatment liquid contains a basic organometallic compound and an ether compound. An active energy ray-curable liquid functional material is ejected from the nozzle of an inkjet head based on an image signal toward the recording medium to be conveyed to form an image, and the active energy ray is irradiated to the recording medium by the active energy ray irradiation means. In the image recording method to be cured,
An image recording method in which a basic processing liquid is introduced at least into the inner wall of the nozzle before the liquid functional material is introduced into the inkjet head.   6. The image recording method according to claim 5, wherein the introduction of the basic processing liquid is after the liquid functional material is discharged from the ink jet head.   6. The image recording method according to claim 5, wherein the introduction of the basic treatment liquid is before the liquid functional material is first introduced into the inkjet head.

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