JPWO2008111333A1 - Ink jet printer and ink jet recording method - Google Patents

Abstract

The present invention suppresses the occurrence of precipitates at the ink contact portion in an ink jet recording method in which an image is formed on a recording medium by ejecting at least a cationic polymerization type ink from a nozzle of an ink jet recording head and an ink jet printer used therefor. In addition, an inkjet printer and an inkjet recording method capable of recording an image with excellent ejection stability are provided. This ink jet printer is an ink jet printer used to form an image on a recording medium by ejecting an ink jet ink containing at least a cationic polymerizable monomer from a nozzle of an ink jet recording head. At least one part is comprised with the heat conductive resin whose heat conductivity is 1 W / m * k or more, It is characterized by the above-mentioned.

Description

  The present invention relates to an ink jet printer capable of forming an image using an ink jet ink containing a cationic polymerizable monomer, and an ink jet recording method using the same.

  In recent years, the inkjet recording method is simple and inexpensive, and has been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters. In general, recording is performed using a special inkjet paper having water absorption ability of water-based inkjet ink using water as a main solvent. However, the phase change inkjet method using a solid wax ink at room temperature, mainly a fast-drying organic solvent. Various ink-jet inks other than water-based ink-jet inks have been put into practical use, such as a solvent-based ink-jet system using the ink-jet ink and an actinic ray curable ink-jet method in which crosslinking is performed by irradiation with actinic rays such as ultraviolet rays after recording.

  In particular, the ink jet recording method using actinic ray curable ink jet ink can record on a recording medium having relatively low odor, quick drying, and no ink absorption ability, as compared with the ink jet recording method using solvent ink jet ink. In this respect, attention has been paid in recent years, and techniques of actinic ray curable inkjet inks having various configurations have been disclosed.

  As actinic ray curable ink-jet inks, those using radically polymerizable compounds represented by (meth) acrylates have been put into practical use, but recently, adhesion to recording media, low odor, and polymerization inhibition by oxygen Actinic ray curable ink jet ink using a cationically polymerizable compound and an ink jet printer using the same have been proposed (for example, see Patent Documents 1 and 2).

  On the other hand, in an ink jet printer, a metal such as stainless steel or aluminum is often used as a material constituting an ink supply path or the like in contact with ink jet ink from the viewpoint of economy and ease of processing. (For example, refer to Patent Documents 3 and 4.)

  By using an ink jet printer composed of the metal material as described above, an ink jet ink containing a cationic polymerizable monomer (hereinafter also referred to as a cationic polymerization type ink or simply an ink) is ejected onto a recording medium to record an image. Depending on the environmental conditions used and the constituent materials of the ink supply path inside the ink jet recording head, precipitates may be generated in the ink jet ink, and these precipitates may block the ink supply path and reach the nozzle part. As a result, it has been found that it causes an emission failure. In general, precipitation in actinic ray curable ink-jet inks may be caused by actinic ray leakage light or pigment aggregation, and various measures have been taken to date. It has been found that when a metal material is used as a liquid contact member of an ink jet printer, an undesirable electrochemical reaction occurs and a decomposition product or a polymer of the ink component is generated. As described above, it has been found that when a metal material is used as a liquid contact member of an ink jet printer, an unexpected ink polymerization reaction occurs when the cationic polymerization type ink is brought into contact with the metal material for a long period of time.

Based on the above problems, as a result of examining that the liquid contact member is made of a resin having low conductivity compared to metal, the cationic polymerization type ink is usually in a state of high viscosity. It is warmed to about 40-80 ° C. and discharged after the viscosity is lowered. As described above, it has been found that even when the cationic polymerization type ink is heated, the discharge state varies depending on the type of resin used for the liquid contact material, and stable discharge cannot be performed.
JP 2005-290246 A JP 2004-34543 A JP 2005-238742 A JP 2006-159619 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an inkjet recording method for forming an image on a recording medium by ejecting at least a cationic polymerization type ink from a nozzle of an inkjet recording head, and an inkjet printer used therefor In other words, it is an object of the present invention to provide an ink jet printer and an ink jet recording method capable of suppressing the generation of precipitates at an ink contact portion and performing image recording excellent in ejection stability.

  The above object of the present invention is achieved by the following configurations.

  1. In an inkjet printer used for forming an image on a recording medium by ejecting an inkjet ink containing at least a cationic polymerizable monomer from a nozzle of an inkjet recording head, at least a part of a liquid contact member in contact with the inkjet ink is: An ink-jet printer comprising a heat conductive resin having a heat conductivity of 1 W / m · k or more.

  2. 2. The ink jet printer according to item 1, wherein at least an ink jet recording head of the liquid contact member is made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more.

  3. 3. The ink jet printer according to 1 or 2, wherein at least an intermediate tank of the liquid contact member is made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more.

  4). Among the liquid contact members, at least the ink jet recording head, the intermediate tank, and the connection flow path connecting the ink jet recording head and the intermediate tank are made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more. 4. The ink jet printer according to any one of 1 to 3, wherein the ink jet printer is provided.

  5. The inkjet printer according to any one of 1 to 4, wherein the thermal conductivity of the thermal conductive resin is 2 W / m · k or more.

  6). 6. The ink jet printer according to any one of 1 to 5, wherein the heat conductive resin is an insulating resin.

  7). The inkjet printer according to any one of 1 to 6, wherein the inkjet ink contains a compound having an oxetane ring and an epoxy compound as a cationic polymerizable monomer.

  8). The inkjet printer according to any one of 1 to 7, wherein the inkjet ink contains a vinyl ether compound as a cationic polymerizable monomer.

  9. Using the inkjet printer according to any one of 1 to 6, an inkjet ink containing at least a cationic polymerizable monomer is ejected from a nozzle of an inkjet recording head of the inkjet printer to form an image on a recording medium. An ink jet recording method comprising forming the ink jet recording method.

  10. 10. The ink jet recording method as described in 9 above, wherein the ink jet ink contains a compound having an oxetane ring and an epoxy compound as a cationic polymerizable monomer.

  11. 11. The ink jet recording method as described in 9 or 10 above, wherein the ink jet ink contains a vinyl ether compound as a cationic polymerizable monomer.

  According to the present invention, in an ink jet recording method for forming an image on a recording medium by ejecting at least a cationic polymerization type ink from a nozzle of an ink jet recording head and an ink jet printer used therefor, generation of precipitates at an ink wetted portion is suppressed. In addition, an ink jet printer and an ink jet recording method capable of recording an image with excellent ejection stability can be provided.

1 is a diagram illustrating an overall configuration of an ink jet printer including a filter and an intermediate tank according to an embodiment of the present invention. It is a schematic block diagram which shows an example of the ink supply path structure in the inkjet printer of this invention. FIG. 2 is an exploded perspective view illustrating an example of a configuration of an ink jet recording head applicable to the ink jet printer of the present invention. FIG. 4 is a perspective view showing one of two sets of manifolds provided in the ink jet printer shown in FIG. 3. FIG. 4 is a perspective view showing the other of two sets of manifolds provided in the ink jet printer shown in FIG. 3. It is the front view shown about the irradiation means to irradiate an inkjet recording head and actinic light among the inkjet printers of this invention. FIG. 2 is a top view illustrating an example of a configuration of a main part in a line head type inkjet recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Ink tank 2,73,104 Recording head 3 Active energy ray source 4,103 Carriage 6,110 Filter box 7,108 Intermediate tank 8,102 Ink supply path 41 Inkjet head chip 48a, 48b Manifold 51a, 51b Filter 59 Supply ink channel 61 First communication channel 63 Second communication channel 71 Recording device 72 Head carriage 81 Ink ejection port 74 Irradiation means 75 Platen portion 76 Guide member 77 Bellows structure 78 Irradiation light source 105 Intermediate tank unit 106 Intermediate Tank front chamber 107 Filter 109, 111 Filter adjacent part J1-J6 Joint N Nozzle P Recording material

  Usually, in an inkjet ink containing a cationically polymerizable monomer, a photoacid generator present at the same time generates an acid when irradiated with an actinic ray, and the polymerization of the cationically polymerizable monomer is started by the acid. However, the ink containing the cationic polymerizable composition supplies electrons from the liquid contact portion when it has been stagnated for a long period of time in an ink tank, an ink flow path, and an ink jet recording head (hereinafter also simply referred to as a recording head). When received, an acid is generated in the ink by the transfer of the electrons without irradiation of actinic rays, thereby starting polymerization, and thus an illegal polymerization composition is generated.

  On the other hand, a resin material such as polypropylene is used as a constituent member of an ink jet printer that comes into contact with the ink jet ink from the viewpoint of ink resistance and prevention of the exchange of electrons as described above. In addition, since the cationic polymerization type ink is usually in a high viscosity state, when discharged from an ink jet printer, it is warmed to about 40 to 80 ° C. in order to improve the discharge property, and is discharged after the viscosity is lowered. The However, when the above resin materials are used for the ink wetted part, most of these resin materials have poor thermal conductivity, and in particular, the resin in the vicinity of the heating means and the resin in the region farther from it. The resin in the vicinity of the heating means has a high temperature, while the resin in a region farther from it has a low temperature, and naturally the temperature of the ink in contact with each resin is high and low. Will be mixed. Therefore, the ink viscosity also varies, and as a result, the emission property varies.

  As a result of intensive studies in view of the above-described problems, the present inventors have ejected an inkjet ink containing at least a cationic polymerizable monomer from a nozzle of an inkjet recording head of an inkjet printer to form an image on a recording medium. In the inkjet printer to be formed, an ink jet printer in which a thermal conductive resin having a thermal conductivity of 1 W / m · k or more is applied to at least a part of a liquid contact member of the inkjet printer that is in contact with the inkjet ink. As soon as the present invention has been found, it has been found that a gel can be prevented from being generated due to an illegal polymerization reaction in the channel, and a stable light output can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

<Inkjet printer>
The ink jet printer of the present invention is mainly supplied from an ink tank for storing ink containing a cationic polymerizable monomer, an ink supply path for feeding ink from the ink tank to a recording head, and the ink supply path. A recording head for emitting the ink onto the recording medium, and an actinic ray irradiation light source for curing the ink droplets landed on the recording medium, and the ink supply path of the ink tank and the recording head includes A filter or an intermediate tank is provided.

  FIG. 1 is a diagram showing an overall configuration of an inkjet printer including a filter and an intermediate tank according to an embodiment of the present invention.

  Reference numeral 1 denotes an ink tank that stores and supplies ink containing a cationic polymerizable monomer. In FIG. 1, for example, the ink tank includes a yellow ink tank 1Y, a magenta ink tank 1M, a cyan ink tank 1C, and a black ink tank 1K. Is shown. Reference numeral 2 denotes a recording head having nozzles for ejecting ink droplets onto a recording medium to form an image, and includes a yellow recording head 2Y, a magenta recording head 2M, a cyan recording head 2C, and a black recording head 2K. Reference numeral 3 denotes an active energy ray source that irradiates ink that has landed on the recording medium with ultraviolet rays that are active energy rays.

  Reference numeral 4 denotes a carriage. The carriage 4 integrally mounts the recording head 2 and the energy beam source 3, and is reciprocated as indicated by arrows WX 1 and WX 2 guided by the carriage guide 5 to scan the recording medium P. Then, an image is formed on the recording medium P.

  A filter box 6 includes a yellow filter box 6Y, a magenta filter box 6M, a cyan filter box 6C, and a black filter box 6K. An intermediate tank 7 includes a yellow intermediate tank 7Y, a magenta intermediate tank 7M, a cyan intermediate tank 7C, and a black intermediate tank 7K.

  Ink is sent from the ink tank 1 to the intermediate tank 7 and supplied from the intermediate tank 7 to the recording head 2 through the ink supply path 8. The ink supply path 8 is composed of supply paths for yellow ink, magenta ink, cyan ink, and black ink. Each single color ink is independently supplied from the ink tank 1 via the ink supply path 8 and the recording head. 2 is supplied.

  A maintenance unit 10 performs a recovery process of the recording head 2 and includes a suction cap 9 for capping the recording head 2. A waste ink container 12 for storing waste ink receives and stores ink forcedly ejected from the recording head 2 during flushing.

  FIG. 2 is a schematic configuration diagram showing an example of the ink supply path configuration of the ink jet printer of the present invention.

  In FIG. 2a, the ink tank 101 is connected to the ink supply path 102 via the joint J1, and the end of the ink supply path 102 is stored in the carriage 103 via the joint J2. It is connected to the head 104. Ink droplets are ejected onto the recording medium from the nozzles N of the recording head 104 in accordance with the image formation information, and then, the active energy rays are instantaneously irradiated from the active energy ray source L to cure the ink. .

  FIG. 2B is an example in which an intermediate tank unit 105 with a built-in filter is provided in the middle of the ink supply path 102. The discharge port of the ink tank 101 and the ink supply path 102A are connected by a joint J1, and are connected to the intermediate unit tank 105 via a joint J3. The ink is fed from the joint J3 to the intermediate tank front chamber 106, and then is fed to the intermediate tank 108 by removing a foreign substance or the like by the filter 107. Next, the intermediate tank 108 and the ink supply path 102 </ b> B are connected via a joint J <b> 4, and an ink supply line that supplies filtered ink stored in the intermediate tank 108 to the recording head 104. Note that reference numeral 109 shown in FIG. 2B denotes a filter adjacent portion adjacent to the filter 107.

  FIG. 2c) shows an example in which a filter box 110 is provided in place of the intermediate tank unit 105 in FIG. A filter 107 is provided in the filter box 110 connected to the ink supply path 102A and 102B via the joint J5 and the ink outlet side via the joint J6. , An ink supply line for supplying ink to the recording head 104 after removing foreign matters in the ink. 2 indicates a filter adjacent portion adjacent to the filter 107.

  In FIG. 2 described above, for convenience, only lines for supplying ink to the magenta recording head are shown. However, as shown in FIG. 1, similar supply lines are provided for the yellow recording head and the cyan recording head. The head and the black recording head are also provided. In addition, FIG. 2 shows only the configuration necessary for the description, and although not shown in FIG. 2, for example, an electromagnetic valve, a branch joint, and a liquid feed pump for controlling the liquid delivery of ink, a record A head control unit and the like are provided.

  In the ink jet recording method of the present invention, for example, in the ink jet printer or ink ink supply line shown in FIG. 1 or FIG. 2, 1) an ink tank member for storing ink, 2) an intermediate tank, and 3) ejecting ink from the ink tank. Or at least a part of the liquid contact member constituting the ink supply path to the ink jet recording head, or 4) a heat conductive resin having a thermal conductivity of 1 W / m · k or more. It is configured.

  In the present invention, the liquid contact part is an ink tank, each ink supply path, an intermediate tank unit, a filter box, a joint group connecting them, an ink jet recording head, and an ink containing the cationic polymerizable monomer according to the present invention. For example, in the ink supply line shown in FIG. 2A, the ink supply line includes the inside of the ink tank 101, the inside of the ink supply path 102, the joints J1 and J2, and the inside 104 of the recording head. 2B), the inside of the ink tank 101, the inside of the ink supply path 102, the joints J1 to J4, the filter 107 and the filter adjacent portion 109 of the intermediate tank unit 105, and the inside 104 of the recording head. is there. Further, in the ink supply line shown in FIG. 2C, the inside of the ink tank 101, the inside of the ink supply path 102, the joints J1, J2, J5, and J6, the filter 107 in the filter box 110, the filter adjacent portion 111, and the recording. This is the inside 104 of the head.

  In the present invention, among them, 1) the ink jet recording head, 2) the intermediate tank, or 3) the ink jet recording head, the intermediate tank, and the connection flow path connecting the ink jet recording head and the intermediate tank have a thermal conductivity of 1 W / It is preferable that it is comprised with the heat conductive resin of m * k or more from a viewpoint which can exhibit the objective effect of this invention especially.

  Further, the configuration of the ink jet recording head will be described in detail.

  FIG. 3 is an exploded perspective view of the ink jet recording head 104 applicable to the ink jet printer of the present invention. As shown in FIG. 3, the ink jet recording head 104 includes two ink jet head chips (for ejecting ink). (Hereinafter referred to as a head chip) 41 is provided in an overlapping manner. The head chip 41 has a long outer shape, and a plurality of discharge ports (nozzles) are arranged on the lower end surface (discharge surface). In addition, a substantially rectangular ink supply port 43 is provided on the outer surface of each of the two stacked head chips 41, and the ink supply port 43 and the nozzle are connected via an ink flow path (not shown). Communicate with each other. A part of the ink flow path forms a pressure chamber, and the pressure is changed by the action of a piezoelectric element (not shown) to eject ink droplets from the ejection port. In the head chip 41, two sets of head drive substrates 46 that transmit control signals from the control unit to the piezoelectric elements are connected to the piezoelectric elements via flexible wiring boards 47.

  Two sets of manifolds 48 a and 48 b for supplying ink from the outside to the head chip 41 are attached to both sides of the two head chips 41. 4 and 5 are perspective views showing the structure of each of the two sets of manifolds 48a and 48b. As shown in FIGS. 4 and 5, connecting portions 49 a and 49 b that are connected to the ink supply port 43 and supply ink are provided on the surfaces of the manifolds 48 a and 48 b that face the head chip 41. The connecting portions 49a and 49b have an outer shape substantially the same shape as the ink supply port 43, and first recesses 491a and 491b serving as ink flow paths are provided therein. In addition, the connecting portions 49a and 49b are divided walls 492a and 492a and 491b that secure the communication between the upper and lower portions of the divided first recesses 491a and 491b while dividing the first recesses 491a and 491b in the vertical direction. 492b is formed in a plate shape along the horizontal. In addition, blocking walls 493a and 493b formed in a substantially L shape are provided on the upper rear side of the connecting portions 49a and 49b, and are blocked from the first recesses 491a and 491b by the blocking walls 493a and 493b. Second recesses 494a and 494b are formed.

  In addition, behind the connecting portions 49a and 49b, there are provided third recesses 50a and 50b cut off from the first recesses 491a and 491b and the second recesses 494a and 494b.

  In the front end portions of the manifolds 48a and 48b, injection ports 481a and 481b for injecting ink into the first recesses 491a and 491b are provided in communication with the lower portions of the first recesses 491a and 491b. Above the injection ports 481a and 481b, first communication ports 482a and 482b communicating with the upper portions of the first recesses 491a and 491b are provided. The injection ports 481a and 481b and the first communication ports 482a and 482b are shifted in the front-rear direction so that the injection ports 481a and 481b are positioned forward. In addition, ink receiving portions 483a and 483b that receive ink and guide it to the injection ports 481a and 481b are provided substantially horizontally below the front and lower sides of the injection ports 481a and 481b, respectively, and below the front and lower sides of the first communication ports 482a and 482b. The first floor portions 484a and 484b of the first communication ports 482a and 482b extend substantially horizontally.

  On the opposite sides of the first floor portions 484a and 484b and the ink receiving portions 483a and 483b to the head chip 41, vertical first side walls 485a and 485b are formed.

  Cleaning pipes 486a and 486b for cleaning the inside of the ink flow path immediately after assembly of the ink jet recording head 104 are communicated with the third recesses 50a and 50b at the rear ends of the manifolds 48a and 48b. It is provided to extend toward. Above the cleaning pipes 486a and 486b, second communication ports 487a and 487b communicating with the second recesses 494a and 494b are provided. Second floor portions 488a and 488b of the second communication ports 487a and 487b extend substantially horizontally below the second communication ports 487a and 487b. On the opposite side of the head chip 41 in the second floor portions 488a and 488b, vertical second side walls 489a and 489b are formed.

  Engagement pieces 490a and 490b are provided at the front end portion and the rear end portion of the manifolds 48a and 48b with the head chip 41 interposed therebetween, and the engagement pieces 490a of the one manifold 48a and the other end are provided. Two sets of manifolds 48 a and 48 b are attached to the head chip 41 by engaging with the engaging pieces 490 b of the manifold 48 b.

  The connecting portions 49a and 49b of the manifolds 48a and 48b cover the first recesses 491a and 491b and the second recesses 494a and 494b, and are in contact with the dividing walls 492a and 492b and the blocking walls 493a and 493b (see FIGS. 4 and 5 are indicated by dotted lines). The filters 51 a and 51 b cover the ink supply port 43 of the head chip 41 when the manifolds 48 a and 48 b are attached to the head chip 41. Here, there is a gap between the ink supply port 43 and the filters 51 a and 51 b, and this gap serves as an ink flow path that guides the ink filtered by the filters 51 a and 51 b to the ink supply port 43.

  A holding plate (not shown) that holds the manifolds 48a and 48b and the head chip 41 is attached to the lower portion of the head chip 41 so that the ejection surface is exposed.

  Further, as shown in FIG. 3, the inkjet recording head 104 has a housing in which the components of the inkjet recording head 104 such as the head chip 41, the manifolds 48a and 48b, the head drive substrate 46, and the holding plate are attached and fixed. A body frame 54 is provided, and the housing frame 54 is covered with a cover (not shown).

  In the ink jet recording head having the configuration shown in FIGS. 3 to 5, the main liquid contact members include manifolds 48a and 48b, connecting portions 49a and 49b, filters 51a and 51b, a housing frame 54, and the like.

  In the present invention, a part of the members constituting the liquid contact part is a heat conductive resin having a thermal conductivity of 1 W / m · k or more. It is preferable that all the members constituting the liquid part are made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more. When metal is used for these wetted parts, for example, when contact is made over a long period of time, precipitates are generated, and as a result, the precipitates reach the recording head, resulting in nozzle clogging, nozzle missing or oblique emission. This results in a failure. In addition, when a resin having low thermal conductivity is used, the ejection property becomes unstable due to variations in ink viscosity when heated.

  Therefore, in the ink jet printer of the present invention, the generation of precipitates can be suppressed by making the liquid contact portion a highly heat conductive resin.

<Heat conductive resin>
In the present invention, the heat conductive resin may be either a resin itself having a heat conductivity or a resin that has been made heat conductive by containing a heat conductive filler. .

  The heat conductive resin material applied to the ink wetted part of the ink jet printer of the present invention is not particularly limited as long as it is a thermoplastic resin forming a resin matrix, and any one of known thermoplastic resins can be used. It can be appropriately selected and used. Examples of such thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, nylon resins such as nylon 6, nylon 6,6, nylon 11, nylon 12, and aromatic polyamide, polyethylene terephthalate, polybutylene terephthalate. Polyester resins such as polycyclohexylmethylene terephthalate, ABS resin, polycarbonate resin, modified polyphenylene ether resin, polyacetal resin, polyphenylene sulfide resin, wholly aromatic polyester resin, polyether ether ketone resin, polyether sulfone resin, polysulfone resin, polyamide Examples thereof include imide resins and copolymer resins composed of two or more constituent components of these resins. These thermoplastic resins may be used alone or in combination of two or more.

  On the other hand, as the thermally conductive resin material according to the present invention, a filler-containing high thermal conductive resin containing a filler dispersed in a thermoplastic resin matrix can be used. There is no particular limitation as long as the conductivity is high, and various types of fillers can be used. Specifically, oxide powder such as aluminum oxide (alumina), zinc oxide, magnesium oxide, silicon dioxide, nitride powder such as boron nitride, aluminum nitride, silicon nitride, gold, silver, aluminum, iron, copper, etc. Metal powder, silicon carbide powder, or the like can be used.

  When the particle size of the high thermal conductive filler is small, the viscosity of the compound is remarkably increased at the time of filling, and the filling tends to be difficult. As a result, a resin material having high thermal conductivity cannot be obtained. There is. Further, when the particle diameter is increased, the resin material may be peeled off and mixed into the ink. Therefore, the average particle size of the high thermal conductive filler used for the filler-containing high thermal conductive resin is preferably 2 to 80 μm, more preferably 3 to 50 μm.

  In the present invention, the high thermal conductive filler may be used alone or in combination of two or more. Further, the content thereof is preferably 30% by volume or more from the viewpoint of conductivity of the resin material, and preferably 70% by volume or less from the viewpoint of moldability with respect to the total volume of the heat conductive resin material. Considering the balance between thermal conductivity and moldability, the preferable content of the high thermal conductivity filler is selected in the range of 50 to 70% by volume.

If necessary, additives such as other fillers, flame retardants, heat resistance improvers, weather resistance improvers and the like can be blended with the heat conductive resin material used in the present invention. Examples of the other fillers include mica, talc, fibers such as carbon fiber and glass fiber, and fillers having a large reinforcing effect such as whiskers. Specific examples of whiskers include non-oxide whiskers made of silicon carbide, silicon nitride, etc., metal oxide whiskers made of ZnO, MgO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , potassium titanate, and the like. In addition, a double oxide whisker made of aluminum borate, basic magnesium sulfate, or the like can be mentioned. Of these, a double oxide whisker is preferable because it can be easily combined with plastic.

  In order to prepare the heat conductive resin material according to the present invention, a conventionally known method, for example, a thermoplastic resin, a high heat conductive filler, and other additives used as required are blended, and a heat kneader, for example, uniaxial extrusion. A melt kneading method using a machine, a twin screw extruder, a roll, a Banbury mixer, a plastic bender, a kneader, a high shear mixer, or the like can be used.

  The heat conductive resin according to the present invention has a heat conductivity of 1 W / m · k or more, preferably 2 W / m · k or more, more preferably 2 W / m · k or more, 50 W. / M · k or less, particularly preferably 5 W / m · k or more and 30 W / m · k or less.

  The thermal conductivity according to the present invention can be measured according to a method in accordance with JIS-A-1412. As a specific measuring device, for example, a thermal conductivity meter (AUTO-AHC-072) manufactured by Hidehiro Seiki Co., Ltd. is used. ), Thermophysical property measuring apparatus TPA-501 (manufactured by Kyoto Electronics Industry Co., Ltd.) using a hot disk method.

Further, as the heat conductive resin according to the present invention, it can be used even if it is conductive or insulating, but from the viewpoint that the object effect of the present invention can be further exerted, it is insulating. The resin material is preferably 1 × 10 ¹⁰ Ω · cm ² or more as the surface resistivity.

<Inkjet ink>
Next, each component of the inkjet ink used in the inkjet recording method of the present invention will be described sequentially.

[Cationically polymerizable monomer]
One feature of the ink according to the present invention is that it is a cation polymerizable curable inkjet ink containing at least a cation polymerizable monomer.

  In the ink according to the present invention, various known cationic polymerizable monomers can be used as the cationic polymerizable monomer, and among them, it is preferable to use a compound having an oxetane ring and an epoxy compound, and further to them. In addition, it is preferable to contain a vinyl ether compound.

(Compound having oxetane ring)
The compound having an oxetane ring that can be suitably used in the present invention will be described.

<Oxetane compound having an oxetane ring substituted at the 2-position>
In the ink according to the present invention, an oxetane compound having at least one oxetane ring substituted at the 2-position represented by the following general formula (14) in the molecule is preferably used as the cationic polymerizable monomer.

In the general formula (14), R _{1 to} R ₆ each represent a hydrogen atom or a substituent. However, at least one of the groups represented by R _{3 to} R ₆ is a substituent. In the general formula (14), examples of the substituent represented by R _{1 to} R ₆ include a fluorine atom and an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, or a butyl group). ), A C1-C6 fluoroalkyl group, an allyl group, an aryl group (for example, a phenyl group, a naphthyl group, etc.), a furyl group, or a thienyl group. Moreover, these groups may further have a substituent.

<Oxetane compound having one oxetane ring in the molecule>
Furthermore, among the general formula (14), compounds having an oxetane ring represented by the following general formulas (15) to (18) are preferably used.

In the formula, R _{1 to} R ₆ each represent a hydrogen atom or a substituent, R ₇ and R ₈ each represent a substituent, and Z independently represents an oxygen or sulfur atom, or contains an oxygen or sulfur atom in the main chain. The divalent hydrocarbon group which may be sufficient. In the general formula (15) to (18), the substituent represented by R ₁ to R ₆ have the same meanings as the substituents represented by R ₁ to R ₆ in the general formula (14).

In the general formulas (15) to (18), the substituent represented by R ₇ or R ₈ is an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, or a butyl group). An alkenyl group having 1 to 6 carbon atoms (for example, 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group) Or a 3-butenyl group), an aryl group (for example, a phenyl group, a naphthyl group, etc.), an aralkyl group (for example, a benzyl group, a fluorobenzyl group, a methoxybenzyl group, etc.), an acyl group having 1 to 6 carbon atoms (for example, , A propylcarbonyl group, a butylcarbonyl group or a pentylcarbonyl group), an alkoxycarbonyl group having 1 to 6 carbon atoms (for example, an ethoxycarbonyl group, a propoxycarbonyl group). Group, butoxycarbonyl group etc.), represents the number 1-6 alkylcarbamoyl group having a carbon (e.g., propylcarbamoyl group, butyl pentylcarbamoyl group), alkoxy carbamoyl group (e.g., such as ethoxy carbamoyl group).

  In the general formulas (15) to (18), an oxygen or sulfur atom represented by Z or a divalent hydrocarbon group which may contain an oxygen or sulfur atom in the main chain is an alkylene group (for example, ethylene Group, trimethylene group, tetramethylene group, propylene group, ethylethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, etc.), alkenylene group (for example, vinylene group, propenylene group) Etc.) and alkynylene groups (for example, ethynylene group, 3-pentynylene group, etc.), and the carbon atom of the alkylene group, alkenylene group or alkynylene group may be replaced by an oxygen atom or a sulfur atom.

Among the above substituents, R ₁ is preferably a lower alkyl group (eg, a methyl group, an ethyl group, a propyl group, etc.), and an ethyl group is particularly preferably used. R ₇ and R ₈ are preferably a propyl group, a butyl group, a phenyl group or a benzyl group, and Z is preferably a hydrocarbon group containing no oxygen or sulfur atom (an alkylene group, an alkenylene group, an alkynylene group or the like).

<Compounds having two or more oxetane rings in the molecule>
In the present invention, a compound having two or more oxetane rings in a molecule represented by the following general formulas (19) and (20) can be used.

In the formula, Z is synonymous with the group used in the general formulas (15) to (18), and m represents 2, 3 or 4. R _{1 to} R ₆ are a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, etc.), a fluoroalkyl group having 1 to 6 carbon atoms, allyl Represents a group, an aryl group (for example, a phenyl group, a naphthyl group, etc.) or a furyl group. However, in General formula (19), at least one of R < ₃ > -R < ₆ > is a substituent.

In the formula, R ₉ is selected from the group consisting of a linear or branched alkylene group having 1 to 12 carbon atoms, a linear or branched poly (alkyleneoxy) group, or the following general formulas (22), (23) and (24). Represents a divalent group.

  As an example of the branched alkylene group having 1 to 12 carbon atoms, an alkylene group represented by the following general formula (21) is preferably used.

In the formula, R ₁₀ represents a lower alkyl group (for example, a methyl group, an ethyl group, a propyl group, etc.).

In the formula, n represents 0 or an integer of 1 to 2000, and R ₁₂ represents an alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group). R ₁₁ represents an alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, Nonyl group or the like) or a group represented by the following general formula (25).

In the formula, j represents 0 or an integer of 1 to 100, and R ₁₃ represents an alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group). Octyl group, nonyl group and the like.

Wherein, R ₁₄ is a hydrogen atom, C 1 -C 10 alkyl group having a carbon (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, etc.), C1-C10 alkoxy group (for example, methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, etc.), halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), nitro group , A cyano group, a mercapto group, an alkoxycarbonyl group (for example, a methyloxycarbonyl group, an ethyloxycarbonyl group, a butyloxycarbonyl group, etc.) or a carboxyl group.

In the formula, R ₁₅ represents an oxygen atom, a sulfur atom, —NH—, —SO—, —SO ₂ —, —CH ₂ —, —C (CH ₃ ) ₂ —, or —C (CF ₃ ) ₂ —. To express.

The aspect of preferred partial structure of the compound having an oxetane ring used in the present invention, for example, the general formula (19), in (20), R ₁ is a lower alkyl group (e.g., methyl group, ethyl group, propyl Group, etc.), preferably an ethyl group. Further, R ₉ is preferably a hexamethylene group or one in which R ₁₄ is a hydrogen atom in the general formula (23).

In the general formula (21), R ₁₀ is an ethyl group, R ₁₂ and R ₁₃ are methyl groups, and Z is a hydrocarbon group containing no oxygen or sulfur atom.

  Furthermore, as an example of the preferable aspect of the compound which has an oxetane ring which concerns on this invention, the compound represented by following General formula (26) is mentioned.

In the formula, r is an integer of 25 to 200, and R ₁₆ represents an alkyl group having 1 to 4 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc.) or a trialkylsilyl group. R ₁ , R ₃ , R ₅ and R ₆ have the same meanings as the substituents represented by R _{1 to} R ₆ in the general formula (14). However, at least one of R _{3 to} R ₆ is a substituent.

  Hereinafter, although the specific example of the compound which has an oxetane ring substituted by 2-position which concerns on this invention is shown as exemplary compounds 1-15, this invention is not limited to these.

1: trans-3-tert-butyl-2-phenyloxetane 2: 3,3,4,4-tetramethyl-2,2-diphenyloxetane 3: di [3-ethyl (2-methoxy-3-oxetanyl)] Methyl ether 4: 1,4-bis (2,3,4,4-tetramethyl-3-ethyl-oxetanyl) butane 5: 1,4-bis (3-methyl-3-ethyloxetanyl) butane 6: di ( 3,4,4-trimethyl-3-ethyloxetanyl) methyl ether 7: 3- (2-ethyl-hexyloxymethyl) -2,2,3,4-tetramethyloxetane 8: 2- (2-ethyl-hexyl) Oxy) -2,3,3,4,4-pentamethyl-oxetane 9: 4,4'-bis [(2,4-dimethyl-3-ethyl-3-oxetanyl) methoxy] biphenyl 1 : 1,7-bis (2,3,3,4,4- pentamethyl - oxetanyl) heptane)
11: Oxetanyl silsesquioxane 12: 2-methoxy-3,3-dimethyloxetane 13: 2,2,3,3-tetramethyloxetane 14: 2- (4-methoxyphenyl) -3,3-dimethyloxetane 15: Di (2- (4-methoxyphenyl) -3-methyloxetane-3-yl) ether The compound having an oxetane ring substituted at least at the 2-position was synthesized with reference to the documents described below. can do.

(1) Hu Xianming, Richard M. et al. Kellogg, Synthesis, 533-538, May (1995)
(2) A. O. Fitton, J .; Hill, D.C. Ejane, R.A. Miller, Synth. , 12, 1140 (1987)
(3) Toshiro Imai and Shinya Nishida, Can.
J. et al. Chem. Vol. 59, 2503-2509 (1981)
(4) Nobujiro Shimizu, Shintaro Yamaoka, and Yuho Tsuno, Bull. Chem. Soc. Jpn. 56, 3853-3854 (1983)
(5) Walter Fisher and Cyril A.M. Grob, Helv. Chim. Acta. , 61, 2336 (1978)
(6) Chem. Ber. 101, 1850 (1968)
(7) “Heterocyclic Compounds with Three- and Four-membered Rings”, Part Two, Chapter IX, Interscience Publishers, John Wiley & Sons, NewYor (1964).
(8) Bull. Chem. Soc. Jpn. 61, 1653 (1988)
(9) Pure Appl. Chem. , A29 (10), 915 (1992)
(10) Pure Appl. Chem. , A30 (2 &amp; 3), 189 (1993)
(11) JP-A-6-16804 (12) German Patent 1,021,858 The content of the compound having an oxetane ring substituted at least at the 2-position in the ink according to the present invention is as follows. 1-97 mass% is preferable, More preferably, it is 30-95 mass%.

<Combination of oxetane compound and other monomers>
In addition, the compound having an oxetane ring substituted at least at the 2-position according to the present invention may be used alone, or two types having different structures may be used in combination, and a photopolymerizable monomer described later. And photopolymerizable compounds such as polymerizable monomers can be used in combination. When used in combination, the mixing ratio is preferably adjusted so that the compound having an oxetane ring substituted at least at the 2-position is 10 to 98% by mass in the mixture, and other photopolymerizable monomers and polymerizable monomers. It is preferable to adjust the photopolymerizable compound such as 2 to 90% by mass.

<Oxetane compound having a substituent only at the 3-position>
In the ink according to the present invention, the oxetane compound having a substituent at the 2-position and a conventionally known oxetane compound can be used in combination, and among them, an oxetane compound having a substituent only at the 3-position can be preferably used together.

  Here, as the oxetane compound having a substituent only at the 3-position, for example, known compounds as introduced in JP-A Nos. 2001-220526 and 2001-310937 can be used.

  Examples of the compound having a substituent only at the 3-position include a compound represented by the following general formula (27).

In the general formula (27), R ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, an allyl group, or an aryl group. , Furyl group or thienyl group. R ² is a methyl group, an ethyl group, a propyl group, butyl alkyl group having 1 to 6 carbon atoms such as, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl group, 2-methyl-2 -Alkenyl groups having 2 to 6 carbon atoms such as propenyl group, 1-butenyl group, 2-butenyl group and 3-butenyl group, aromatic groups such as phenyl group, benzyl group, fluorobenzyl group, methoxybenzyl group and phenoxyethyl group A group having a ring, an alkylcarbonyl group having 2 to 6 carbon atoms such as an ethylcarbonyl group, a propylcarbonyl group and a butylcarbonyl group, an alkoxy having 2 to 6 carbon atoms such as an ethoxycarbonyl group, a propoxycarbonyl group and a butoxycarbonyl group Carbonyl group, ethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group, pentylcarbamoyl group Number 2-6 carbons of an N- alkylcarbamoyl group.

  As the oxetane compound that can be used in the present invention, it is particularly preferable to use a compound having one oxetane ring because it has excellent adhesion to a recording medium, low viscosity, and excellent workability.

  An example of a compound having two oxetane rings includes a compound represented by the following general formula (28).

In the general formula (28), R ¹ is the same group as that in the general formula (27).
R ³ is, for example, a linear or branched alkylene group such as an ethylene group, a propylene group or a butylene group, a linear or branched poly (alkyleneoxy) such as a poly (ethyleneoxy) group or a poly (propyleneoxy) group. ) Group, propenylene group, methylpropenylene group, butenylene group or other linear or branched unsaturated hydrocarbon group, alkylene group containing carbonyl group or carbonyl group, alkylene group containing carboxyl group, alkylene containing carbamoyl group Group.

R ³ can also include a polyvalent group selected from the groups represented by the following general formulas (29), (30) and (31).

In the general formula (29), R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or a carbon such as a methoxy group, an ethoxy group, a propoxy group or a butoxy group. It is a C 1-4 alkoxy group, a halogen atom such as a chlorine atom or a bromine atom, a nitro group, a cyano group, a mercapto group, a lower alkoxycarbonyl group, a carboxyl group or a carbamoyl group.

In the general formula (30), R ⁵ represents an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (CF ₃ ) ₂ or C (CH ₃ ) ₂ .

In General Formula (31), R ⁶ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, or an aryl group. n is an integer of 0-2000. R ⁷ is a methyl group, an ethyl group, a propyl group, a butyl group having 1 to 4 carbon atoms, or an aryl group. Examples of R ^{7 also} include a group selected from the group represented by the following general formula (32).

In the general formula (32), R ⁸ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or a butyl group, or an aryl group. m is an integer of 0-100.

  Specific examples of the compound having two oxetane rings include the following compounds.

Illustrative compound 1 is a compound in which R ¹ is an ethyl group and R ³ is a carboxyl group in the general formula (28). Exemplary compound 2 is a compound in which R ¹ is an ethyl group, R ³ is the general formula (31), R ⁶ and R ⁷ are methyl groups, and n is 1 in the general formula (28).

In the compound having two oxetane rings, a preferred example other than the above compound is a compound represented by the following general formula (33). In the general formula (33), R ¹ has the same meaning as R ¹ in the general formula (27).

  An example of a compound having 3 to 4 oxetane rings is a compound represented by the following general formula (34).

In the general formula (34), R ¹ has the same meaning as R ¹ in the general formula (27). As R ⁹ , for example, a branched alkylene group having 1 to 12 carbon atoms such as groups represented by the following A to C, a branched poly (alkyleneoxy) group such as a group represented by the following D, or the following E And branched polysiloxy groups such as those shown. j is 3 or 4.

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

  Illustrative compound 3 is an example of a compound having 3 to 4 oxetane rings.

  Furthermore, examples of the compound having 1 to 4 oxetane rings other than those described above include compounds represented by the following general formula (35).

In the general formula (35), R ⁸ has the same meaning as R ⁸ in the general formula (32). R ¹¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group or a trialkylsilyl group, and r is 1 to 4.

  In the present invention, preferred specific examples of the oxetane compound include the exemplified compounds 4, 5, and 6 shown below.

  The method for producing each compound having an oxetane ring described above is not particularly limited, and may be a conventionally known method. (1957)) discloses a method for synthesizing an oxetane ring from a diol. In addition to these, compounds having 1 to 4 oxetane rings having a high molecular weight of about 1000 to 5000 are also included. Specific examples of these compounds include the following exemplified compounds 7, 8, and 9.

(Epoxy compound)
As an epoxy compound applicable to the ink according to the present invention, any of a monomer having an epoxy group and an oligomer thereof can be used. Specific examples include conventionally known aromatic epoxy compounds, alicyclic epoxy compounds, and aliphatic epoxy compounds. Hereinafter, the epoxy compound means a monomer or an oligomer thereof. As the oligomer in the present invention, a low molecular weight compound is preferable, and an oligomer having a molecular weight of less than 1000 is more preferable.

  A preferable aromatic epoxy compound is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, for example, bisphenol A or its Examples thereof include di- or polyglycidyl ethers of alkylene oxide adducts, hydrogenated bisphenol A or di- or polyglycidyl ethers of alkylene oxide adducts thereof, and novolak-type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxy compound, 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. Alternatively, a cyclopentene oxide-containing compound is preferable, and specific examples include the compounds shown below.

  Preferred examples of the aliphatic epoxy compound include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol and diglycidyl ether of propylene glycol. Or polyglycidyl ether of polyhydric alcohol such as diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, glycerin or alkylene oxide adduct thereof, polyethylene glycol or alkylene oxide thereof Diglycidyl ether, poly (alkylene glycol) such as polypropylene glycol or diglycidyl ether of alkylene oxide adducts thereof Include diglycidyl ether of. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  In addition to these compounds, monoglycidyl ethers of aliphatic higher alcohols and monoglycidyl ethers of phenol and cresol, which are monomers having one oxirane ring in the molecule, can also be used. Among these epoxy compounds, in view of fast curability, aromatic epoxy compounds and alicyclic epoxy compounds are preferable, and alicyclic epoxy compounds are particularly preferable. In the present invention, one of the above epoxy compounds may be used alone, but two or more may be used in appropriate combination.

  Specific examples of the epoxy compound that can be preferably used in the present invention are listed below.

  The addition amount of the alicyclic epoxy compound is preferably 10% by mass or more from the viewpoint of reducing the variation in curability with respect to temperature and humidity with respect to the total mass of the ink, and maintains the strength of film physical properties after curing. It is preferable to contain at 80 mass% or less from the point of carrying out. In the present invention, one type of alicyclic epoxy compound may be used alone, or two or more types may be used in appropriate combination.

  These alicyclic epoxy compounds may be produced by any method, for example, see Maruzen KK Publishing, 4th Edition Experimental Chemistry Course 20 Organic Synthesis II, 213, 1992, Ed. By Alfred Hasfner, The Chemistry of Heterocyclic compounds, Vol. 5, No. 5, Advertisement, Small Ring Heterocycles Part 3, Oxilanes, John & Wiley and Sons, An Inc. 42, 1986, Yoshimura, Adhesion, Vol. 30, No. 7, 42, 1986, Japanese Patent Application Laid-Open No. 11-1000037, Japanese Patent No. 2906245, Japanese Patent No. 2926262, and the like.

  The actinic ray curable composition of the present invention contains an epoxidized fatty acid ester or an epoxidized fatty acid glyceride as an epoxy compound.

  By using epoxidized fatty acid ester or epoxidized fatty acid glyceride in combination with oxetane compound / alicyclic epoxy compound system, it is not only preferable from the viewpoint of safety / environment such as AMES and sensitization, skin irritation, odor, etc. Conventional problems such as generation of wrinkles due to curing shrinkage and poor curability and dischargeability can be solved depending on the curing environment (temperature, humidity).

  The epoxidized fatty acid ester and epoxidized fatty acid glyceride that can be used in the present invention are not particularly limited as long as an epoxy group is introduced into the fatty acid ester or fatty acid glyceride.

  The epoxidized fatty acid ester is produced by epoxidizing an oleic acid ester, and examples thereof include methyl epoxy stearate, butyl epoxy stearate, octyl epoxy stearate and the like. Similarly, epoxidized fatty acid glyceride is produced by epoxidizing soybean oil, linseed oil, castor oil and the like, and epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil and the like are used.

(Vinyl ether compound)
Examples of vinyl ether compounds that can be used in the ink of the present invention include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, and hexanediol divinyl ether. Di- or trivinyl ether compounds such as vinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane trivinyl ether, ethyl vinyl ether, butyl vinyl ether, i-butyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethano Mono vinyl ether, propyl vinyl ether, i- propyl vinyl ether, i- propenyl ether -O- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.

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

(Cationic polymerization initiator)
In the present invention, an onium salt can be used as a cationic polymerization initiator (photopolymerization initiator). Examples of onium salts include sulfonium salts, oxonium salts, iodonium salts, and the like.

  The sulfonium salt used as the cationic polymerization initiator in the present invention is preferably a sulfonium salt compound represented by the following general formulas [1] to [4].

In the above general formulas [1] to [4], R _{31 to} R ₄₇ each represent a hydrogen atom or a substituent, R _{31 to} R ₃₃ do not simultaneously represent a hydrogen atom, and R _{34 to} R ₃₇ simultaneously represent It does not represent a hydrogen atom, R _{38 to} R ₄₁ do not represent a hydrogen atom at the same time, and R _{42 to} R ₄₇ do not represent a hydrogen atom at the same time.

The substituent represented by R _{31 to} R ₄₇ is preferably an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, or a hexyl group, Alkoxy groups such as methoxy group, ethoxy group, propyl group, butoxy group, hexyloxy group, decyloxy group, dodecyloxy group, acetoxy group, propionyloxy group, decylcarbonyloxy group, dodecylcarbonyloxy group, methoxycarbonyl group, ethoxycarbonyl Group, carbonyl group such as benzoyloxy group, phenylthio group, halogen atom such as fluorine, chlorine, bromine and iodine, cyano group, nitro group and hydroxy group.

X ₃₁ represents a non-nucleophilic anion residue, and examples thereof include halogen atoms such as F, Cl, Br, and I, B (C ₆ F ₅ ) ₄ , R ₁₈ COO, R ₁₉ SO ₃ , SbF ₆ , AsF ₆ , PF ₆ , BF _{4 and the} like can be mentioned. However, R ₁₈ and R ₁₉ are each an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, a halogen atom such as fluorine, chlorine, bromine or iodine, a nitro group, a cyano group, a methoxy group or an ethoxy group. Represents an alkyl group or a phenyl group which may be substituted with an alkoxy group. Among these, B (C ₆ F ₅ ) ₄ and PF ₆ are preferable from the viewpoint of safety.

  The above compounds can be obtained from THE CHEMICAL SOCIETY OF JAPAN Voi. 71 no. 11, 1998, as well as the photoacid generator described in “Organic Materials for Imaging”, edited by Organic Electronics Materials Research Group, Bunshin Publishing (1993), can be easily synthesized by a known method.

In the present invention, it is particularly preferable that the sulfonium salt represented by the general formulas [1] to [4] is at least one sulfonium salt selected from the following general formulas [5] to [13]. X ₃₁ represents a non-nucleophilic anion residue and is the same as described above.

  In the present invention, the sulfonium salt represented by the general formulas (1) to (4) is particularly preferably at least one of the sulfonium salts selected from the general formulas (5) to (13). X represents a non-nucleophilic anion residue and is the same as described above.

Illustrative compounds including iodonium salts include the following compounds in addition to X = PF _{6 in} the formulas (5) to (13).

  In the actinic ray curable composition of the present invention, the photopolymerization initiator preferably contains an onium salt in an amount of 1% by mass to less than 5% by mass. If the onium salt is less than 1% by mass, the curability may be deteriorated. On the other hand, when it is contained in an amount of 5% by mass or more, the curability is improved, but the storage stability is liable to deteriorate.

[Color material]
The ink according to the present invention preferably contains a pigment as a coloring material. The pigments that can be preferably used in the present invention are listed below.

C. I Pigment Yellow-1, 3, 12, 13, 14, 17, 42, 74, 81, 83, 87, 93, 95, 109, 120, 128, 138, 139, 151, 166, 180, 185
C. I Pigment Orange-16, 36, 38
C. I Pigment Red-5, 22, 38, 48: 1, 48: 2, 48: 4, 49: 1, 53: 1, 57: 1, 63: 1, 101, 122, 144, 146, 177, 185
C. I Pigment Violet-19, 23
C. I Pigment Blue-15: 1, 15: 3, 15: 4, 18, 60, 27, 29
C. I Pigment Green-7, 36
C. I Pigment White-6, 18, 21
C. I Pigment Black-7
For the dispersion of the pigment, for example, a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, or the like can be used. As the dispersion medium, it is preferable in view of dispersion suitability to select a photopolymerizable compound, and among them, a monomer having the lowest viscosity.

  The pigment is preferably dispersed so that the average particle size of the pigment particles is 0.08 to 0.5 μm, and the maximum particle size is 0.3 to 10 μm, preferably 0.3 to 3 μm. Select the dispersion medium, dispersion conditions, and filtration conditions as appropriate. 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.

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

  As the pigment dispersant, one having a basic anchor portion is preferably used, and a polymer dispersant having a comb structure is more preferably used.

  Specific examples of pigment dispersants that can be used in the present invention include Solsperse 9000, 17000, 18000, 19000, 20000, 24000SC, 24000GR, 24000GR, 28000, 32000, Ajinomoto Fine-Techno Co., Ltd. manufactured by Avecia. Examples include Addispar PB821, PB822, PLAAD ED214, ED251, DISPARLON DA-325, DA-234, EFKA-5207, 5244, 6220, 6225, etc. manufactured by Enomoto Kasei. In addition, pigment derivatives (synergists) that can be used in combination with the pigment dispersant include specific examples of pigment derivatives such as Avecia Solsperse 5000, 12000, 22000, EFKA EFKA-6746, 6750, and the like. Can be mentioned.

  In the ink according to the present invention, the viscosity at 25 ° C. is preferably 10 mPa · s or more and less than 50 mPa · s.

(Additive)
In the ink according to the present invention, various additives other than those described above can be used. For example, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes can be added. In addition, for the purpose of improving storage stability, any known basic compound can be used, but representative examples include basic alkali metal compounds, basic alkaline earth metal compounds, amines, fatty acid amine salts, Examples include basic organic compounds such as various rust inhibitors.

"recoding media"
Various recording media can be used as the recording medium used when forming an image with the ink jet printer of the present invention. From the viewpoint that the characteristics of the actinic radiation curable ink according to the present invention can be fully exhibited. It is preferable that the recording medium does not substantially have the absorption capacity of, such as ordinary non-coated paper, coated paper, etc., as well as various non-absorbing plastics and films used for so-called soft packaging, As various plastic films, for example, polyethylene terephthalate (PET) film, stretched polystyrene (OPS) film, stretched polypropylene (OPP) film, stretched nylon (ONy) film, polyvinyl chloride (PVC) film, polyethylene (PE) film, Triacetyl cellulose (TAC) And the like can be given Irumu. As other plastics, polycarbonate, acrylic resin, ABS, polyacetal, polyvinyl alcohol (PVA), rubbers and the like can be used. Moreover, it is applicable also to metals and glass. Among these recording media, the configuration of the present invention is effective particularly when an image is formed on a PET film, OPS film, OPP film, ONy film, or PVC film that can be shrunk by heat. These substrates are not only susceptible to curling and deformation of the film due to ink curing shrinkage and heat generation during the curing reaction, but also the ink film is difficult to follow the substrate shrinkage.

  The surface energies of these various plastic films differ greatly, and depending on the recording medium, the dot diameter after ink landing has been a problem in the past. The ink according to the present invention forms a good high-definition image on a wide range of recording media having a surface energy of 35 to 60 mN / m, including OPP films having a low surface energy, OPS films, and PET having a relatively large surface energy. it can.

  In the present invention, it is more advantageous to use a long (web) recording medium in terms of the cost of the recording medium such as the packaging cost and production cost, the production efficiency of the print, and the ability to cope with printing of various sizes. is there.

<Inkjet recording method>
Next, an ink jet recording method using the ink jet printer of the present invention will be described.

  In the ink jet recording method of the present invention, a method is preferred in which the ink according to the present invention is ejected and drawn on a recording medium by an ink jet recording method, and then the ink is cured by irradiation with an actinic ray such as ultraviolet rays.

(Total ink film thickness after ink landing)
In the present invention, the total ink film thickness after the ink has landed on the recording medium and cured by irradiation with actinic rays is preferably 2 to 25 μm. In the actinic ray curable inkjet recording in the screen printing field, the total ink film thickness currently exceeds 25 μm, but in the flexible packaging printing field where the recording medium is often a thin plastic material, the recording medium described above is used. In addition to the problem of curling and wrinkles, there is a problem in that the entire printed material is changed in its strain and texture.

  Here, “total ink film thickness” means the maximum value of the film thickness of the ink drawn on the recording medium, and even for a single color, other two colors are superimposed (secondary color), three colors are superimposed, four colors are used. Even when recording is performed by the overlapping (white ink base) inkjet recording method, the meaning of the total ink film thickness is the same.

(Ink ejection conditions)
As the ink ejection conditions, it is preferable from the viewpoint of ejection stability that the recording head and ink are heated to 35 to 100 ° C. and ejected. Actinic radiation curable ink has a large viscosity fluctuation range due to temperature fluctuations, and the viscosity fluctuations directly affect the droplet size and droplet ejection speed, causing image quality degradation, so keep the temperature constant while raising the ink temperature It is necessary. The control range of the ink temperature is set temperature ± 5 ° C., preferably set temperature ± 2 ° C., more preferably set temperature ± 1 ° C. Moreover, in this invention, it is preferable that the amount of droplets discharged from each nozzle is 2 to 15 pl.

(Light irradiation conditions after ink landing)
In the image forming method of the present invention, the active light is preferably irradiated for 0.001 second to 1 second after the ink landing, more preferably 0.001 second to 0.5. Seconds. In order to form a high-definition image, it is particularly important that the irradiation timing is as early as possible.

In the ink jet recording method according to the present invention, after the ink composition is attached to a recording medium, light irradiation is performed. The light irradiation may be visible light irradiation or ultraviolet irradiation, and ultraviolet irradiation is particularly preferable. When performing ultraviolet irradiation, ultraviolet ray irradiation quantity is 100 mJ / cm ² or more, preferably 500 mJ / cm ² or more and 10,000 / cm ² or less, preferably performed at 5,000 mJ / cm ² or less. An ultraviolet irradiation amount within such a range is advantageous because a sufficient curing reaction can be carried out and the colorant can be prevented from fading due to ultraviolet irradiation. Examples of ultraviolet irradiation include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low-pressure mercury lamps, and high-pressure mercury lamps. For example, a commercially available product such as an H lamp, a D lamp, or a V lamp manufactured by Fusion System can be used.

  A metal halide lamp has a continuous spectrum as compared with a high-pressure mercury lamp (main wavelength is 365 nm), has high luminous efficiency in the range of 200 to 450 nm, and has a long wavelength range. Therefore, a metal halide lamp is suitable when a pigment is used as a coloring material, as in the actinic ray curable inkjet ink according to the present invention.

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

  Further, a method of irradiating actinic rays in two stages, first irradiating actinic rays by the above-described method within 0.001 to 2 seconds after ink landing, and irradiating actinic rays after completion of all printing is also preferable. This is one aspect. By dividing the irradiation of actinic rays into two stages, it is possible to further suppress the shrinkage of the recording medium that occurs during ink curing.

  Conventionally, in the UV ink jet system, a light source with high illuminance in which the total power consumption of the light source exceeds 1 kW · hr is usually used in order to suppress dot spreading and bleeding after ink landing. However, when these light sources are used, particularly in printing on a shrink label or the like, the shrinkage of the recording medium is so large that it cannot be used practically.

  In the present invention, it is preferable to use an actinic ray having a maximum illuminance in a wavelength region of 254 nm, and a high-definition image can be formed even when a light source having a total power consumption of 1 kW · hr or more is used, and the recording medium is contracted. Within practically acceptable level.

  In the present invention, it is preferable that the total power consumption of the light source for irradiating actinic rays is less than 1 kW · hr. Examples of the light source having a total power consumption of less than 1 kW · hr include, but are not limited to, a fluorescent tube, a cold cathode tube, a hot cathode tube, and an LED.

(Inkjet printer)
Next, an image recording method using the ink jet printer of the present invention described in detail with respect to the configuration will be described with reference to the drawings.

  FIG. 6 is a front view showing the ink jet recording head and the irradiation means for irradiating actinic rays among the ink jet printers shown in FIGS.

  The recording apparatus 71 includes a head carriage 72, a recording head 73, an irradiation unit 74, a platen unit 75, and the like. In the recording apparatus 71, a platen unit 75 is installed under the recording medium P. The platen unit 75 has a function of absorbing ultraviolet rays, and absorbs excess ultraviolet rays that have passed through the recording medium P. As a result, a high-definition image can be reproduced very stably.

  The recording medium P is guided by the guide member 76, and moves from the near side to the far side in FIG. 6 by the operation of the conveying means (not shown). The head scanning means (not shown) scans the recording head 73 held by the head carriage 72 by reciprocating the head carriage 72 in the Y direction in FIG.

  The head carriage 72 is installed on the upper side of the recording medium P, and accommodates a plurality of recording heads 73 to be described later according to the number of colors used for image printing on the recording medium P and an ink discharge port 81 on the lower side. . The head carriage 72 is installed with respect to the main body of the recording apparatus 71 in such a manner that it can reciprocate in the Y direction in FIG. 6, and reciprocates in the Y direction in FIG. 6 by driving the head scanning means.

  In FIG. 7, the head carriage 72 is white (W), yellow (Y), magenta (M), cyan (C), black (K), light yellow (Ly), light magenta (Lm), light cyan ( Lc), light black (Lk), and white (W) are drawn as storage heads 73, but in the implementation, the number of colors of the recording heads 73 stored in the head carriage 72 is appropriately set. It can be decided.

  The recording head 73 is configured to discharge ink by operating an ejection unit (not shown) provided with a plurality of actinic ray curable inks (for example, UV ink) supplied by an ink supply unit (not shown). The ink is discharged from the outlet 81 toward the recording medium P. The UV ink ejected by the recording head 73 is composed of a coloring material, a polymerizable monomer, an initiator, and the like. The monomer crosslinks and polymerizes when the initiator acts as a catalyst when irradiated with ultraviolet rays. It has the property of being cured by reaction.

  The recording head 73 moves from one end of the recording medium P to the other end of the recording medium P in the Y direction in FIG. 6 by driving the head scanning means. On the other hand, UV ink is ejected as ink droplets, and ink droplets are landed on the landable area.

  The above scanning is performed as many times as necessary, and after UV ink is ejected toward one landable area, the recording medium P is appropriately moved from the front to the back in FIG. 6 by the conveying means, and scanning by the head scanning means is performed again. 6, the recording head 73 discharges UV ink to the next landable area adjacent to the rearward direction in FIG.

  An image is formed on the recording medium P by repeating the above operation and discharging UV ink from the recording head 73 in conjunction with the head scanning unit and the conveying unit.

  The irradiation unit 74 includes an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength. Here, as the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (Light Emitting Diode) and the like can be applied. A cathode tube, a hot cathode tube, a mercury lamp or black light is preferred. In particular, a low-pressure mercury lamp, a hot cathode tube, a cold cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can effectively prevent bleeding and control the dot diameter. By using black light as the radiation source of the irradiation means 74, the irradiation means 74 for curing the UV ink can be produced at low cost.

  The irradiating means 74 has substantially the same shape as the maximum area that can be set by the recording apparatus (UV inkjet printer) 71 among the landable areas in which the recording head 73 ejects UV ink by a single scan driven by the head scanning means. , Having a shape larger than the landable area.

  The irradiation means 74 is fixed on both sides of the head carriage 72 so as to be substantially parallel to the recording medium P.

  As described above, as means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 73 is shielded, but in addition, the ink discharge of the recording head 73 is determined from the distance h1 between the irradiation means 74 and the recording medium P. It is effective to increase the distance h2 between the outlet 81 and the recording medium P (h1 <h2) or to increase the distance d between the recording head 73 and the irradiation means 74 (d is increased). Further, it is more preferable that a bellows structure 77 is provided between the recording head 73 and the irradiation means 4.

  Here, the wavelength of the ultraviolet rays irradiated by the irradiation unit 74 can be changed as appropriate by exchanging the ultraviolet lamp or filter provided in the irradiation unit 74.

  The ink jet printer of the present invention can also form an image using a line head type recording apparatus.

  FIG. 7 is a top view showing another example of the configuration of the main part of the line head type inkjet recording apparatus. The ink jet recording apparatus shown in FIG. 7 is called a line head system, and a plurality of ink jet recording heads 73 of each color are fixedly arranged on a head carriage 72 so as to cover the entire width of the recording medium P. Yes.

  On the other hand, on the downstream side of the head carriage 72, there is provided irradiation means 74 that is arranged so as to cover the entire area of the ink printing surface so as to cover the entire width of the recording medium P. As the ultraviolet lamp used for the illumination means 74, the same one as described in FIG. 6 can be used.

  In this line head system, the head carriage 72 and the irradiation means 74 are fixed, and only the recording medium P is conveyed, and ink ejection and curing are performed to form an image. In the present invention, the recording medium P is desirably heated to 35 to 60 ° C.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<Preparation of ink set>
(Preparation of pigment dispersion)
(Preparation of yellow pigment dispersion)
A yellow pigment dispersion was prepared according to the method described below.

  The following two compounds were placed in a stainless beaker and dissolved on a hot plate with heating and stirring at 65 ° C.

Azisper PB822 (dispersant manufactured by Ajinomoto Fine Techno Co., Ltd.) 8 parts by mass Aron Oxetane OXT-221 (Oxetane compound manufactured by Toagosei Co., Ltd.) 72 parts by mass Next, after cooling to room temperature, C.I. I. After adding 20 parts by mass of Pigment Yellow 150 (manufactured by LANXESS, E4GN-GT CH20015) and sealing with 200 parts of zirconia beads having a diameter of 0.3 mm in a glass bottle, the mixture was subjected to a dispersion process for 4 hours using a paint shaker. The zirconia beads were removed to prepare a yellow pigment dispersion.

(Preparation of magenta pigment dispersion)
In the preparation of the yellow pigment dispersion, the pigment is C.I. I. In place of Pigment Yellow 150, C.I. I. A magenta pigment dispersion was prepared in the same manner except that it was changed to Pigment Red 122 (manufactured by Dainichi Seika Co., Ltd., custom-made).

(Preparation of cyan pigment dispersion)
In the preparation of the yellow pigment dispersion, the pigment is C.I. I. In place of Pigment Yellow 150, C.I. I. A cyan pigment dispersion was prepared in the same manner except that it was changed to Pigment Blue 15: 4 (Sanyo Color Co., Ltd., Cyanine Blue 4044).

(Preparation of black pigment dispersion)
In the preparation of the yellow pigment dispersion, the pigment is C.I. I. In place of Pigment Yellow 150, C.I. I. A black pigment dispersion was prepared in the same manner except that it was changed to Pigment Black 7 (Mitsubishi Chemical Corporation, # 52).

[Preparation of ink set 1]
An ink set 1 including the following yellow ink Y1, magenta ink M1, cyan ink C1, black ink K1, light yellow ink Ly1, light magenta ink Lm1, light cyan ink Lc1, and light black ink Lk1 was prepared.

(Preparation of yellow ink Y1)
Using the yellow pigment dispersion prepared above (yellow pigment: 20% by mass, dispersant PB822: 8% by mass, photopolymerizable compound OXT-221: 72% by mass) and the following additives, yellow ink Y1 Was prepared.

  Specifically, after mixing all the following additives other than the yellow pigment dispersion and confirming that it was sufficiently dissolved, this mixed solution was added little by little to the yellow pigment dispersion with stirring for 15 minutes. After stirring, filtration was performed with a PP3 μm disk filter manufactured by Loki Techno.

Yellow pigment 3.0 parts by weight Dispersant: PB822 (manufactured by Ajinomoto Fine Techno) 1.0 part by weight Vinyl ether compound: DVE-3 (triethylene glycol divinyl ether (manufactured by ISP)) 86.4 parts by weight Photopolymerization initiator: UVI6992 (triphenylsulfonium salt, manufactured by Dow Chemical Company)
5.0 parts by mass Polymerization inhibitor (triisopropanolamine) 0.1 parts by mass Propylene carbonate 2.0 parts by mass Silicon surfactant: KF-351 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by mass Sensitizer: DBA (9,10-dibutoxyanthracene) 0.5 part by mass Water 1.0 part by mass Next, after preparing the ink liquid, the surface tension value at 25 ° C. was adjusted to 27 mN / m, and then the hollow fiber membrane Using a degassing module (Dainippon Ink Chemical Co., Ltd., SEPAREL PF-004D), a yellow ink Y1 having a pigment concentration of 3.0% by mass was prepared.

(Preparation of magenta ink M1, cyan ink C1, black ink K1)
In the preparation of the yellow ink Y1, a magenta pigment having a pigment concentration of 3.0% by mass was similarly obtained except that the yellow pigment dispersion was changed to a magenta pigment dispersion, a cyan pigment dispersion, and a black pigment dispersion, respectively. Ink M1, cyan ink C1, and black ink K1 were prepared.

(Preparation of light yellow ink Ly1, light magenta ink Lm1, light cyan ink Lc1, and light black ink Lk1)
In the preparation of the yellow ink Y1, the magenta ink M1, the cyan ink C1, and the black ink K1, the light yellow ink Ly1, the light magenta ink Lm1, and the light cyan were similarly changed except that the pigment concentrations were changed to 0.6% by mass. Ink Lc1 and light black ink Lk1 were prepared.

[Preparation of ink set 2]
An ink set 2 including the following yellow ink Y2, magenta ink M2, cyan ink C2, black ink K2, light yellow ink Ly2, light magenta ink Lm2, light cyan ink Lc2, and light black ink Lk2 was prepared.

(Preparation of yellow ink Y2)
Using the yellow pigment dispersion prepared above (yellow pigment: 20% by mass, dispersant PB822: 8% by mass, photopolymerizable compound OXT-221: 72% by mass) and the following additives, yellow ink Y2 Was prepared.

  Specifically, after mixing all the following additives other than the yellow pigment dispersion and confirming that it was sufficiently dissolved, this mixed solution was added little by little to the yellow pigment dispersion with stirring for 15 minutes. After stirring, filtration was performed with a PP3 μm disk filter manufactured by Loki Techno.

Yellow pigment 3.0 parts by weight Dispersant: PB822 (manufactured by Ajinomoto Fine Techno) 1.0 part by weight Compound having an oxetane ring: Oxetane OXT221 (manufactured by Toagosei Co., Ltd., bifunctional)
50.0 parts by mass A compound having an oxetane ring: Oxetane OXT212 (manufactured by Toagosei, monofunctional)
7.0 parts by mass A compound having an oxetane ring: Oxetane OXT101 (manufactured by Toagosei, monofunctional)
3.0 parts by mass Alicyclic epoxy compound: Celoxide 2021P (manufactured by Daicel Chemical Industries, Ltd., bifunctional)
26.4 parts by mass Photopolymerization initiator: Exemplified compound S-2 5.0 parts by mass Polymerization inhibitor (triisopropanolamine) 0.1 part by mass Propylene carbonate 2.0 parts by mass Silicon surfactant: KF-351 ( (Shin-Etsu Chemical Co., Ltd.) 0.1 parts by mass Sensitizer: DBA (9,10-dibutoxyanthracene) 0.5 parts by mass water 0.6 parts by mass Next, after preparing the ink liquid, the surface at 25 ° C. The tension value was adjusted to 27 mN / m, then degassing was performed using a degassing module (Dainippon Ink & Chemicals, SEPAREL PF-004D) using a hollow fiber membrane, and the pigment concentration was 3. A 0 mass% yellow ink Y2 was prepared.

(Preparation of magenta ink M2, cyan ink C2, black ink K2)
In the preparation of the yellow ink Y2, a magenta pigment having a pigment concentration of 3.0% by mass was similarly obtained except that the yellow pigment dispersion was changed to a magenta pigment dispersion, a cyan pigment dispersion, and a black pigment dispersion, respectively. Ink M2, cyan ink C2, and black ink K2 were prepared.

(Preparation of light yellow ink Ly2, light magenta ink Lm2, light cyan ink Lc2, and light black ink Lk2)
In the preparation of the yellow ink Y2, the magenta ink M2, the cyan ink C2, and the black ink K2, the light yellow ink Ly2, the light magenta ink Lm2, and the light cyan are the same except that the respective pigment concentrations are changed to 0.6% by mass. Ink Lc2 and light black ink Lk2 were prepared.

(Preparation of ink sets 3 and 4)
Ink sets 3 and 4 were prepared in the same manner as in the preparation of the ink set 2 except that the types and amounts of the additives were changed as shown in Table 1.

  In addition, the detail of each compound described by the abbreviation in Table 1 is as follows. Moreover, the numerical value of Table 1 represents a mass part.

(Cationically polymerizable monomer)
<Compound having oxetane ring>
OXT221: Oxetane OXT221 (Toagosei, bifunctional)
OXT101: Oxetane OXT101 (manufactured by Toagosei, monofunctional)
OXT212: Oxetane OXT212 (manufactured by Toagosei, monofunctional)
<Vinyl ether compound>
DVE-3: Triethylene glycol divinyl ether (manufactured by ISP)
<Alicyclic epoxy compound>
S2021P: Celoxide 2021P (manufactured by Daicel Chemical Industries, bifunctional)
S3000: Celoxide 3000 (manufactured by Daicel Chemical Industries, bifunctional)
EP-1: Exemplary compound EP-1
(Photopolymerization initiator)
UVI6992: triphenylsulfonium salt, manufactured by Dow Chemical Company S-2: exemplary compound S-2
CI 5102: iodonium salt, manufactured by Nippon Soda Co., Ltd. (basic compound)
TPA: Triisopropanolamine (surfactant)
KF-351: manufactured by Shin-Etsu Chemical Co., Ltd., silicon-based surfactant (dispersant)
PB822: Ajinomoto Fine Techno Co., Ltd., polymer dispersant (sensitizer)
DBA: 9,10-dibutoxyanthracene (others)
PC: Propylene carbonate << Inkjet printer >>
[Inkjet printer 1]
The ink tank 101 and the joints J1 to J4 are made of SUS316 (stainless steel: 18% chromium, 12% nickel, 2.5% molybdenum) using an ink jet printer having the ink supply line shown in FIG. The ink supply path 102A is an insulating member in which an ink-resistant Teflon (registered trademark) tube having a thermal conductivity of 0.2 W / m · k is covered with a black polyolefin tube.

  The intermediate unit tank 105 and the recording head 104 are also made of SUS316, and the ink supply path 102B that connects the intermediate unit tank 105 and the recording head 104 is an insulating member and has a heat conductivity of 0.2 W / m · k. An ink Teflon (registered trademark) tube covered with a black polyolefin tube was used.

  Further, heating members were attached to the intermediate unit tank 105 and the recording head 104, and heating was performed at 50 ° C. from the outside.

[Production of inkjet printers 2 to 25]
In the production of the inkjet printer 1, the same applies except that the members constituting the intermediate unit tank 105, the recording head 104, and the ink supply path 102B connecting the intermediate unit tank 105 and the recording head 104 are changed as shown in Table 2. Thus, inkjet printers 2 to 25 were produced.

  In addition, the detail of each structural member described with the abbreviation in Table 2 is as follows.

SUS316: Stainless steel (chrome 18%, nickel 12%, molybdenum 2.5%)
AL6061: Aluminum Table 3 shows the details of the thermally conductive resin (thermal conductivity, electrical conductivity).

<Evaluation>
The following evaluations were performed on recording methods 1 to 100 in which the ink jet printers and ink sets described in Tables 4 to 7 were combined.

[Evaluation of precipitation resistance]
Each ink jet printer produced above was filled with ink sets from the ink tank 101 to the recording head 104 in the combinations shown in Tables 4-7. After being filled for 3 days in an environment of 23 ° C., the presence or absence of precipitates in the intermediate unit tank 105 and the recording head 104 was visually observed, and the precipitation resistance was evaluated according to the following criteria.

5: No occurrence of precipitates on the inner wall of the target member 4: Slight generation of fine precipitates is observed on the inner wall of the target member, but there is no problem 3: Deposits on the inner wall of the target member Although the generation | occurrence | production of generation | occurrence | production is recognized somewhat, there is no influence on output property Level 2: Although generation | occurrence | production of deposit is recognized in the wide range of the inner wall of a target member, the level which influence on output property is a concern 1: The inner wall of an object member The generation of coarse precipitates is observed in a wide range of the above, and the level is not practical (Evaluation of ejection stability)
Each ink jet printer produced above was filled with ink sets from the ink tank 101 to the recording head 104 in the combinations shown in Tables 4-7. The recording head 104 is configured to be able to eject multi-size dots with 256 nozzles and 2 to 20 pl at a resolution of 720 × 720 dpi (dpi represents the number of dots per 2.54 cm), and recording with the intermediate unit tank 105. A heating member was attached to the head 104, and continuous discharge was performed for 3 hours while heating at 50 ° C. from the outside. Next, the emission state of each color ink was visually observed to determine the average emission state of each color ink, and the ejection stability was evaluated according to the following criteria.

5: No nozzle missing or exit bend is observed in all nozzles 4: No nozzle missing is observed in all nozzles, but weak exit bend is observed in only a few nozzles 3: No nozzle missing is observed in all nozzles, but nozzles with exit bends are observed in 1 to 3 locations. 2: Nozzle missing is observed with some nozzles, but nozzles with exit bends are clearly 1 or more recognized at four or more locations 1: Obvious nozzle missing and exiting bending occur frequently, and cannot be practically used. Tables 4 to 7 show the results obtained as described above.

  As is clear from the results shown in Tables 4 to 7, the thermal conductivity according to the present invention is 1 W / m · k or more in the recording head, the intermediate unit tank, or the recording head, the intermediate unit tank, and the ink supply path 102B. The recording method of the present invention using the inkjet printer of the present invention composed of the heat conductive resin of the present invention has better deposition resistance than the comparative example, and the continuous emission is performed while heating the intermediate unit tank 105 and the recording head 104. It can be seen that the ejection stability when performed is excellent.

Claims (11)

  In an inkjet printer used for forming an image on a recording medium by ejecting an inkjet ink containing at least a cationic polymerizable monomer from a nozzle of an inkjet recording head, at least a part of a liquid contact member in contact with the inkjet ink is: An ink-jet printer comprising a heat conductive resin having a heat conductivity of 1 W / m · k or more.   2. The ink jet printer according to claim 1, wherein at least an ink jet recording head of the liquid contact member is made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more.   The at least intermediate tank among the said liquid contact members is comprised with the heat conductive resin whose heat conductivity is 1 W / m * k or more, The range of Claim 1 or 2 characterized by the above-mentioned. Inkjet printer.   Among the liquid contact members, at least the ink jet recording head, the intermediate tank, and the connection flow path connecting the ink jet recording head and the intermediate tank are made of a heat conductive resin having a thermal conductivity of 1 W / m · k or more. The ink jet printer according to any one of claims 1 to 3, wherein the ink jet printer is provided.   The inkjet printer according to any one of claims 1 to 4, wherein the thermal conductivity of the thermal conductive resin is 2 W / m · k or more.   The inkjet printer according to any one of claims 1 to 5, wherein the heat conductive resin is an insulating resin.   The inkjet printer according to any one of claims 1 to 6, wherein the inkjet ink contains a compound having an oxetane ring and an epoxy compound as a cationic polymerizable monomer.   The inkjet printer according to any one of claims 1 to 7, wherein the inkjet ink contains a vinyl ether compound as a cationically polymerizable monomer.   Using the inkjet printer according to any one of claims 1 to 6, an inkjet ink containing at least a cationic polymerizable monomer is ejected from a nozzle of an inkjet recording head of the inkjet printer, An ink-jet recording method comprising forming an image on a recording medium.   The ink jet recording method according to claim 9, wherein the ink jet ink contains a compound having an oxetane ring and an epoxy compound as a cationically polymerizable monomer.   11. The ink jet recording method according to claim 9, wherein the ink jet ink contains a vinyl ether compound as a cationic polymerizable monomer.