JP4903530B2 - Inkjet recording method and inkjet recording apparatus - Google Patents

Description

  The present invention relates to an ink jet recording method and an ink jet recording apparatus, and more particularly to an ink jet recording method and an ink jet recording apparatus suitable for forming a high-quality image at high speed using multiple liquids.

  An ink jet system that discharges ink in droplets from an ink discharge port such as a nozzle is used in many printers because it is small and inexpensive, and can form an image without contact with a print medium. Among these ink jet methods, the piezo ink jet method that ejects ink using deformation of piezoelectric elements and the thermal ink jet method that ejects ink droplets by utilizing the boiling phenomenon of ink due to thermal energy achieve high resolution and high printability. It has the feature of being excellent.

  2. Description of the Related Art Currently, high speed and high image quality when ink is ejected onto a non-water-absorbing recording medium such as plain paper or plastic by an ink jet printer are important issues.

  Ink-jet recording continuously discharges ink (liquid) droplets as droplet n1, droplet n2, droplet n3,..., Droplet nx, and droplets n1 and n2 on a recording medium. , Droplets n3,..., Lines are formed with droplets nx, and an image is formed. However, when it takes a long time to dry the droplets after droplet ejection, bleeding occurs in the image. It is likely to occur, and mixing occurs between the adjacent ink droplets n1 and n2, which not only prevents sharp image formation, but also when a non-water-absorbing recording medium is used, the solvent is dried. Because of its slow speed, there was a problem in practical use, such as the need to dry the recorded material without stacking immediately after printing. When mixing between droplets, adjacent droplets that have been struck are united to cause movement of the droplets, so that they deviate from the landing position, and when drawing thin lines, the line width is uneven. When a colored surface is drawn, color unevenness or the like occurs.

  One of the methods for suppressing image bleeding and non-uniform line width is a method for promoting ink curing. As one of them, a technique for hardening and fixing by radiation rather than volatilization of the ink solvent has been proposed. Furthermore, in order to give a high-definition drawing property, there is one that uses a two-component ink and causes both to react on a recording medium. For example, after attaching a liquid having a basic polymer, an anion A method of recording an ink containing a dye (for example, see Patent Document 1) or a method of applying an ink containing an anionic compound and a coloring material after applying a liquid composition containing a cationic substance (for example, patents) Document 2), a recording method using an ink containing a photocurable resin on one side and a photopolymerization initiator on the other (for example, see Patent Document 3), and the like.

  However, these methods have a certain effect in suppressing blurring of the image, but are insufficient for eliminating the non-uniform line width and color unevenness caused by mixing between droplets. Therefore, there is a concern that the drying speed is slow due to the presence of the dye, and the precipitated dye is likely to be unevenly distributed, resulting in a decrease in image quality.

As a technique related to the above, there is a technique in which a pigment is used as a coloring component and cured and fixed by radiation (for example, see Patent Document 4). Here, a pixel is formed using one of an ink containing a solidifying monomer and an ink containing a pigment dispersion, and then the pixel is formed at the same point as the image on the other side. Etc. are described.
In addition, an ink composition containing a reactive monomer, a colorant, and the like together with water and an aggregating solution containing an aggregating agent that generates an agglomerate are used, and after the aggregating solution is adhered onto a recording medium, the ink composition There is one that describes attaching an object (for example, see Patent Document 5). Furthermore, there is a description that a monomer-containing ink composition is applied after the reaction liquid containing a photopolymerization initiator is applied over the entire surface, and ultraviolet irradiation is performed (for example, see Patent Document 6).

  In addition to the above, there is also a description relating to ink ejection that is divided into two types and overlapped with each other (see, for example, Patent Document 7).

  On the other hand, when an image is recorded on, for example, a transparent plastic film with the two-component ink that is cured by radiation as described above, it is difficult to obtain a sufficient density in observation by visible light reflection. In the case of observing a recorded image by visible light reflection, it is effective to use an ink containing a white pigment to obtain a sufficient reflection density (see, for example, Patent Documents 8 to 10).

However, the white pigment-containing ink is applied as a reflective layer, and it is a standard method to drop ink of each color onto it after solidifying. However, when image formation is performed according to this standard method, there is a problem that the inks of the respective colors interfere on the white pigment-containing ink layer. In order to avoid this problem, it is conceivable that the ink for each color is ejected after forming a white pigment-containing ink layer as a liquid for avoiding droplet ejection interference. In the case of liquid inks, separately applying a liquid for avoiding droplet ejection interference and a white pigment-containing ink causes a further increase in the thickness of the film, resulting in a problem of distortion of the film due to shrinkage or the like. It was.
Japanese Unexamined Patent Publication No. 63-60783 JP-A-8-174997 Japanese Patent No. 3478495 Japanese Patent Laid-Open No. 8-21818 JP 2001-348519 A Japanese Patent No. 3642152 JP 2000-135781 A JP 2003-183551 A JP 2004-59627 A JP 2004-18546 A

  The present invention has been made in view of the above, and is capable of forming a high-quality image with excellent long-term storage stability, with reduced bleeding and droplet ejection interference between adjacent jet inks, and a recording medium. It is an object of the present invention to provide an ink jet recording method which is excellent in fixability with an image and which can obtain a sufficient reflection density, and an ink jet recording apparatus suitable for carrying out the recording method.

The present invention has been made by finding that the increase in ink film thickness as described above can be avoided by giving white ink the ability to prevent droplet ejection interference. That is, the present invention
(1) In an inkjet recording method for recording a desired image by ejecting the first liquid A onto a recording medium with at least a first droplet a1 and a droplet a2.
The first liquid A contains a polymerizable or crosslinkable material for forming the image, and the droplet a1 and the droplet a2 are overlapped with an overlapping ratio of 10% or more and 90% or less. The second liquid B, which is a white ink containing a white pigment and having a composition different from that of the first liquid A, is the same as or more than the image formed with the first liquid A. even leave granted in advance the recording medium in a wide range, during the period from by applying a second liquid B until the first liquid a ejects droplets, the applied surface of the second liquid B An ink jet recording method characterized by maintaining a liquid state.

(2) The ink jet recording method according to (1), wherein an overlapping rate at an overlapping portion of the droplet a1 and the droplet a2 is 30% or more and 70% or less .

(3) The second liquid B contains at least a polymerization initiator that causes a crosslinking reaction of the polymerizable or crosslinkable material in the first liquid A. (1) or (2) Ink jet recording method.

(4) From (1), wherein the second liquid B contains a lipophilic solvent, and the content of the lipophilic solvent is 50% by mass or more of the total mass of the second liquid B. (3) The inkjet recording method according to any one of (3).

(5) The inkjet recording method according to (4), wherein the lipophilic solvent is a high-boiling organic solvent having a boiling point higher than 100 ° C.

(6) The inkjet recording method according to any one of (1) to (5), wherein the first liquid A further includes a colorant.

(7) After the application of the second liquid B, the droplet ejection interval until the first droplet a1 is ejected is set to 5 μs or more and 400 milliseconds or less. (1) to (6 The inkjet recording method according to any one of the above.

(8) The droplet size of the first droplet a1 and the droplet a2 is set to 0.1 picoliter or more and 100 picoliter or less, according to any one of (1) to (7) Inkjet recording method.

(9) The method according to any one of (1) to (8), wherein after the first droplet a1 is deposited, active energy is applied to the image to polymerize or crosslink the polymerizable or crosslinkable material. The inkjet recording method described.

(10) transport means for transporting the recording medium;
A liquid application unit for applying a liquid to the recording medium;
An energy applying unit that is disposed on the downstream side in the transport direction of the recording medium from the liquid applying unit, and applies active energy to the liquid applied on the recording medium;
Control means for controlling the conveying means and the energy applying means while discharging liquid from the liquid applying section;
The liquid application unit is provided with a plurality of line-type droplet ejection heads arranged in a direction orthogonal to the conveyance direction of the recording medium to be conveyed and having a length corresponding to the entire width of the recordable area of the recording medium. And
As the plurality of droplet ejection heads, a droplet ejection head that ejects droplets of the first liquid A containing a polymerizable or crosslinkable material for forming an image is different in composition from the first liquid A, And a droplet ejection head that ejects droplets of the second liquid B, which is white ink containing a white pigment,
The droplet ejection head for ejecting the second liquid B, the droplet ejection head for ejecting the first liquid A, and the energy applying means are sequentially arranged from the upstream side in the transport direction of the recording medium , (1) To an inkjet recording method according to any one of (9) to (9) .

(11) Further, it has a droplet ejection head for ejecting droplets of the third liquid C that is white ink containing at least one kind of white pigment, the surface tension γ3 of the third liquid C, and the second In the ink jet recording apparatus described in (10), the surface tension γ2 of the liquid B is γ2 <γ3-3 (mN / m).

(12) A liquid application unit that applies the second liquid B to the upstream side in the transport direction of the recording medium from the liquid application unit instead of the droplet ejection head that ejects the droplet of the second liquid B. The inkjet recording apparatus according to (10) or (11), wherein

  According to the present invention, it is possible to form a high-quality image with excellent long-term storage stability, suppression of bleeding and droplet ejection interference between adjacent jet inks, and excellent fixability between a recording medium and an image. Furthermore, it is possible to provide an ink jet recording method capable of obtaining a sufficient reflection density, and an ink jet recording apparatus suitable for carrying out the recording method.

<Inkjet recording method>
First, the ink jet recording method of the present invention will be described.
The inkjet recording method of the present invention is the inkjet recording method for recording a desired image by ejecting the first liquid A onto the recording medium with at least the first droplet a1 and the droplet a2. The liquid A contains a polymerizable or crosslinkable material for forming the image, and the droplet a1 and the droplet a2 are ejected with overlapping portions, and the composition is different from that of the first liquid A. In addition, the second liquid B, which is a white ink containing a white pigment, is applied to the recording medium in advance in the same range as the image formed with the first liquid A or wider than the image, The surface of the second liquid B that has been ejected is maintained in a liquid state between the time when the second liquid B is applied and the time when the first liquid A is ejected.

  In order to obtain a high image density, if adjacent droplets (first droplet a1 and droplet a2) applied with overlapping portions stay on and contact each other before drying, they merge together. A white ink containing a white pigment in advance before the first droplet a1 and the droplet a2 is deposited, although the blurring of the image and the line width of the thin line are not uniform, and the sharp image formation is likely to be impaired. The second liquid B, which is the same as the image formed with the first liquid A or in a wider range than the image, is applied to the first liquid droplet a1 before the second liquid B is solidified. In addition, by ejecting the droplet a2, even if the droplet a1 and the droplet a2 are applied with overlapping portions, the union between the droplet a1 and the droplet a2 is suppressed, and the bleeding of the image and the image Since the occurrence of line width variations such as thin lines inside is effectively prevented, high image density image resolution While ensuring, it is possible width, sharp line shapes, and thus it is possible to record high quality images. In addition, there is no stickiness and excellent scratch resistance. Furthermore, since the second liquid is white ink, the reflection density of the image by the first liquid A can be sufficiently ensured. That is, the second liquid B has both a function of preventing droplet ejection interference and a function as white ink, and prevents droplet ejection interference by using only one second liquid B. The same effect as that obtained by applying both the liquid and the white ink can be obtained.

In the present invention, it is preferable to use a non-permeable or slowly permeable recording medium as the recording medium in that the effects of the present invention can be remarkably exhibited.
Here, the non-permeable recording medium refers to a medium in which droplets do not substantially penetrate. “Substantially does not penetrate” means that the penetration rate of a droplet after 1 minute is 5% or less. Further, the slowly penetrating recording medium refers to a medium in which when the drop of 10 pl (picoliter) is dropped on the recording medium, the time until the entire liquid amount permeates is 100 milliseconds or more. An example is art paper. Details of the non-permeable or slowly permeable recording medium will be described later.
Note that the permeable recording medium is a medium in which the time until the entire liquid amount penetrates when a 10 pl droplet is dropped on the recording medium is 100 ms or less, specifically, plain paper, For example, porous paper.

  On the recording medium, after the first droplet a1 is ejected, the subsequent first droplet a2 is ejected so as to overlap the droplet a1. Before applying the first droplet a1 and the droplet a2, the second liquid B, which is a white ink containing a white pigment and having a composition different from that of the first liquid A, is previously applied on the recording medium. It is applied to the same area as the image formed by the droplets a1 and the droplet a2 or an area wider than the image, the second liquid B is applied, and then the first liquid A is ejected. In the meantime, the surface of the second liquid B that has been ejected is maintained in a liquid state.

  In the present invention, as the liquid for forming the image, the first liquid A including the first droplet a1 and the droplet a2 and the second liquid B having a composition different from the first liquid A are used. Here, the first droplet a1 and the droplet a2 are droplets in droplets a1, a2, a3,... Ax that are ejected from the ink ejection port using the single first liquid A. It means something that is overlapped and hit by droplets. The droplets may be droplets that are ejected at the same time, or may be the preceding droplet and the succeeding droplet that are the relationship between the preceding droplet and the subsequent droplet, and may be the preceding droplet and the subsequent droplet. preferable. The first liquid A and the second liquid B are liquids having different compositions.

In the present invention, the sp value of the second liquid B to be applied in advance before the application of the first liquid A is set to 35 or less, and the first liquid A and the second liquid B It is preferable to set the difference in sp value between 10 and 10.
When the sp value is 35 or less, the second liquid B is, for example, between the first liquid A (droplet a1, droplet a2,...) containing a polymerizable or crosslinkable material as described later. Affinity is increased, and when the first droplet a1 and the droplet a2 are applied with overlapping portions, the coalescence of the droplets can be suppressed, and the line width of the image blur and the thin line in the image Variations can be effectively prevented.

  In the second liquid, the sp value is more preferably 30 or less, and particularly preferably 25 or less. Further, the difference in sp value between the first liquid A and the second liquid B is more preferably 5 or less.

  In addition, when the difference in sp value between the first liquid A and the second liquid B is within the above range, the liquid a is easily dissolved, and the liquid droplet a1 is the second liquid than the liquid droplet a2. B has a larger contact area with the second liquid B, so that the affinity with the second liquid B is better. Therefore, for example, the droplet a1, the droplet a2,. When .. contains a colorant, it is effective in causing color bleeding and color mixing between the droplets a1 and a2, and avoiding line width variation of a colored line image.

The sp value is defined for various solvents and solutes, and is a value indicating the ease of dissolution between solvent / solvent and between solvent / solute. This value is calculated from the change in energy when the solvent and the solvent are mixed, and when the solute dissolves in the solvent, the sp value used in the present invention is specifically the sp value by Tohoku University RLsmith. It is obtained by calculation with a value calculation program. In the calculation, with reference to 25 ° C., except for compounds not containing carbon atoms, the structural units such as polymers and polyethylene chains are saturated repeating units having bonds (for example, —CH ₂ —CH (C in the case of styrene). ₆ H ₅₎ -) and then, water _{(H 2} O) is calculated as 47.8.

  In the ink jet recording method of the present invention, the first droplet a1 and the droplet a2 described above are ejected using an ink jet nozzle or the like, and the ink jet nozzle is not necessarily used for the second liquid B. It is not limited to application by spraying, but can be applied by other liquid application means such as coating.

  Next, an application unit for applying the second liquid B onto the recording medium will be described. The droplet ejecting means for ejecting the first droplet a1 and the droplet a2 (first liquid A) will be described focusing on the ejection using the inkjet nozzle as described above. A specific example is shown below.

(I) Coating using a coating device A second liquid B is coated on a recording medium using a coating device, and then droplets a1 and a2 (first liquid A) are ejected by an inkjet nozzle. A mode in which an image is recorded by dropping is suitable.

The coating apparatus is not particularly limited and can be appropriately selected from known coating apparatuses according to the purpose, for example, an air doctor coater, a blade coater, a lot coater, a knife coater, a squeeze coater, an impregnation coater, Examples include reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, and extrusion coaters. For details, see Yuji Harasaki's “Coating Engineering”.
The ink jet nozzle is not particularly limited and can be appropriately selected from known nozzles according to the purpose. The ink jet recording method will be described later.

  Note that liquids other than the first liquid droplet a1 and the liquid droplet a2 (first liquid A) and the second liquid B may be used. It may be applied on the recording medium by any method such as jetting by the above-mentioned method, and the timing of application is not particularly limited. In the case of containing a colorant, it is preferable to spray by an ink jet nozzle, and it is preferable to apply after applying the second liquid B.

(Ii) Ejection by inkjet nozzle The second liquid B is ejected by the inkjet nozzle as droplet b1, droplet b2, droplet b3,... Droplet bx, and then the first droplet a1 and droplet A mode in which an image is recorded by ejecting droplets a2, droplets a3,... droplets ax (first liquid A) with an inkjet nozzle is suitable. The ink jet nozzle is the same as described above.

  In this case as well, for any liquid other than the first liquid droplet a1 and the liquid droplet a2 (first liquid A) and the second liquid B, any method such as coating by a coating apparatus or jetting by an inkjet nozzle may be used. And may be applied on the recording medium, and the timing of application is not particularly limited. In the case of containing a colorant, it is preferable that the colorant is injected by an ink jet nozzle, and it is preferable that the second liquid B is applied after being injected from the nozzle.

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

  In the case of the applying means (i), at least the first droplet a1 and the first droplet a2 are ejected onto the second liquid B previously applied on the recording medium by the ink jet recording method. An image is formed. In the case of using the applying unit (ii), at least the first liquid droplet a1 and the first liquid droplet a2 are further ink-jetted on the second liquid B previously applied onto the recording medium by the ink jet recording method. The droplets are ejected by the recording method to form an image.

In the present invention, since the droplet a1 and the droplet a2 have an overlapping portion, the number of droplets deposited per unit length increases, and higher resolution image recording is possible. At this time, the surface of the ejected second liquid B is maintained in a liquid state between the time when the second liquid B is applied and the time when the first liquid A is ejected.
When the second liquid B contains a polymerizable compound or a crosslinkable compound, the liquid state is not solidified, and polymerization or crosslinking may not occur at all. Even if it is progressing, it should be solidified. As a method for determining whether the liquid is liquid or non-liquid, the plain paper is brought into close contact with the portion to which the second liquid B is applied, and when the second liquid B does not move to the plain paper, it is solidified. If it moves, it is determined to be liquid. Here, when a solidification process such as light irradiation enters, the above determination is made within 1 second after the completion of the solidification process. Even if there is a sticky feeling on the surface of the second liquid B, it is determined that it has solidified unless it moves to plain paper. The viscosity in the liquid state may be any viscosity, but is preferably in the range of 1 mPa · s to 100 Pa · s.

The overlap rate when droplets are ejected with an overlapping portion is an overlap rate at least one second after the droplets a1 and a2 overlap and are ejected, and in particular the first droplet a1 is ejected. It is preferable that droplets are ejected such that the overlapping rate at the overlapping portion after 1 second from the droplets of the first droplet a2 after the droplets is 10% or more and 90% or less. It is effective for higher resolution image recording.
Among these, the overlapping rate is preferably 20% or more and 80% or less, and more preferably 30% or more and 70% or less.

  The overlap rate is an index indicating at what rate the adjacent droplets (droplet a1, droplet a2,...) Overlap. Assuming that the diameter of the droplet after landing on the recording medium is a, the overlap ratio is 50% when (1/2) a overlaps. In the case of the present invention, adjacent droplets that are ejected adjacently can maintain the droplet ejection shape without being united with each other, but the overlapping rate is defined as b being the radius of the droplet one second after droplet ejection. When the interval between adjacent droplets is c, 100 × (2b−c) / (2b) [%].

  At the time of image recording, as the balance of the application amount of the second liquid B per droplet of the first droplet a1 and the first droplet a2, the amount of the droplet a1 or the droplet a2 is set to 1. In this case, the application amount (mass ratio) of the second liquid B is preferably in the range of 0.05 to 5, more preferably in the range of 0.07 to 1, and particularly preferably in the range of 0.1 to 1.

The first droplet a1 and / or the droplet a2 are preferably ejected with a droplet size of 0.1 pL (picoliter; the same applies hereinafter) to 100 pL (preferably by an inkjet nozzle). When the droplet size is within the above range, it is effective in that an image having a high sharpness can be drawn with a density. More preferably, it is 0.5 pL or more and 50 pL or less.
The droplet size of the second liquid B is preferably in the same range as the recording liquid.

  In the present invention, the surface of the ejected second liquid B is maintained in a liquid state after the second liquid B is applied until the first liquid A is ejected. In other words, it does not include a process of curing until the surface of the second liquid B becomes solid until the droplet ejection of the first liquid A is completed. In the period, if the second liquid is solidified without being maintained in a liquid state, the function of preventing the second liquid from causing droplet ejection interference is not exhibited.

  Moreover, it is preferable that the droplet ejection interval after the application of the second liquid B until the first droplet a1 is ejected is in the range of 5 μsec or more and 400 ms or less. It is effective in that the effect of the present invention can be remarkably exhibited when the droplet ejection interval is within the above range. The droplet ejection interval is more preferably 10 μs or more and 300 ms or less, and particularly preferably 20 μs or more and 200 μs or less.

In the present invention, after applying the second liquid B in advance as described above and then depositing the first droplet a1 and the droplet a2, energy is applied from the viewpoint of obtaining excellent fixability. A step of fixing the recorded image by applying can be provided. By applying energy, a curing reaction by polymerization or crosslinking of the polymerizable or crosslinkable material contained therein can be promoted, and a stronger image can be formed more efficiently. For example, in a system including a polymerization initiator, generation of active species due to decomposition of the polymerization initiator is promoted by application of active energy such as actinic light and heating, and due to the increase of active species and temperature rise, the result is due to the active species. The curing reaction by polymerization or crosslinking of the polymerizable or crosslinkable material is accelerated.
The application of energy can be suitably performed by irradiation with active light or heating.

Examples of the active light include ultraviolet rays and visible rays, as well as α rays, γ rays, X rays, electron rays, and the like. Among these, ultraviolet rays and visible rays are preferably used from the viewpoint of cost and safety, and ultraviolet rays are particularly preferred.
The amount of energy required for the curing reaction varies depending on the type and content of the polymerization initiator, but is generally about 1 to 500 mJ / cm ² .

In addition, when energy is applied by heating, it is preferable to heat for 0.1 to 1 second under the condition that the surface temperature of the recording medium is in a temperature range of 40 to 80 ° C.
Heating can be performed using a non-contact type heating means, such as a heating means for passing through a heating furnace such as an oven, a heating means by full exposure of ultraviolet light to visible light to infrared light, etc. are suitable. It is. Examples of light sources suitable for exposure as the heating means include metal halide lamps, xenon lamps, tungsten lamps, carbon arc lamps, mercury lamps and the like.

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

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

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

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

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

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

  Next, the first liquid A (droplet a1, droplet a2,...) And the second liquid B used in the ink jet recording method of the present invention, and various components constituting them will be described in detail.

-1st liquid A (1st droplet a1, droplet a2 ...)-
The first liquid A (first droplet a1, droplet a2,...) According to the present invention is ejected onto a second liquid B, which will be described later, applied in advance on the recording medium and recorded. It constitutes an image and comprises at least a polymerizable or crosslinkable material, preferably a colorant and an oleophilic solvent. Furthermore, it can comprise using a polymerization initiator and another component as needed.

<Polymerizable or crosslinkable material>
The first liquid A (first droplet a1, droplet a2,...) Contains at least one polymerizable or crosslinkable material. The polymerizable or crosslinkable material has a function of causing a polymerization or crosslinking reaction by an initiating species such as a radical generated from a polymerization initiator described later, and curing.

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

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

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

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

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

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

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

The polymerizable or crosslinkable material may be used alone or in combination of two or more.
The content of the polymerizable material in the first liquid or, if necessary, in the second liquid is preferably in the range of 50 to 99.6% by mass with respect to the total solid content (mass) of each droplet. The range of 70-99.0 mass% is more preferable, and the range of 80-99.0 mass% is more preferable.
Moreover, as content in a droplet, the range of 20-98 mass% is preferable with respect to the total mass of each droplet, The range of 40-95 mass% is more preferable, The range of 50-90 mass% is preferable. Particularly preferred.

The first liquid A (first droplet a1, droplet a2,...) Is prepared such that the difference in sp value from the second liquid B is 10 or less. The difference in sp value with the second liquid B applied in advance before the first droplet a1 is ejected is 10 or less and the affinity is high, and when the droplet is ejected in contact with the subsequent droplet a2. The coalescence of droplets can be effectively prevented.
The sp value can be suitably adjusted using a lipophilic solvent, a polymerizable material, etc., which will be described later. For example, the sp value can be further lowered by increasing the ratio of the lipophilic solvent in the droplets.

  Details and preferred embodiments of the colorant, lipophilic solvent, polymerization initiator, and other components that can be contained in the first liquid A (first droplet a1, droplet a2,...) Will be described later. .

-Second liquid B-
In the present invention, before the above-described first droplet a1 is deposited, droplets are previously formed on the recording medium with at least the first droplet a1 and the droplet a2 on the recording medium. The first ink is a white ink having a composition different from that of the first droplet a1, the droplet a2,... (First liquid A) and containing a white pigment in the same region as that of the image or a region wider than the image. The liquid B of 2 is provided.

  The second liquid B which is a white ink according to the present invention includes a white pigment, a pigment dispersant, a solvent, and may include other necessary components.

  White pigments include calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amorphous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, lithopone, zeolite, barium sulfate, calcium sulfate, titanium oxide, Inorganic white pigments such as zinc sulfide, zinc oxide, zinc carbonate, barium carbonate, silica antimony trioxide, titanium phosphate, magnesium oxide and magnesium hydroxide, organic pigments such as styrene pigment, acrylic pigment, urea resin and melamine resin Etc. are preferable. Among these white pigments, inorganic white pigments are preferable, and titanium oxide is particularly preferable. These pigments may be used alone or in combination of two or more.

  The particle size of the white pigment is preferably a number average particle size of 0.1 to 0.5 μm. By setting the particle size in the above range, it is possible to effectively avoid a decrease in whiteness or a decrease in gloss.

  The titanium oxide may be either a rutile type or an anatase type, and these may be used alone or in combination. Further, any of those manufactured by the sulfuric acid method and those manufactured by the chlorine method may be used. Examples of the titanium oxide include hydrous alumina treatment, hydrous silicon dioxide treatment, or surface coating treatment with an inorganic substance such as zinc oxide treatment, trimethylolmethane, trimethylolethane, trimethylolpropane, and 2,4-dihydroxy-2. -It can select suitably from what carried out surface coating processing by organic substances, such as methylpentane, or siloxane processing, such as polydimethylsiloxane.

  The refractive index of the white pigment is preferably 1.5 or more. When a white pigment having a refractive index in this range is included, a high-quality image can be formed.

  In the present invention, any dispersant may be used, but a polymer dispersant is preferably used.

  Examples of the polymer dispersant include a polymer dispersant such as 4000 series manufactured by efka, a Solsperse series manufactured by Zeneca, and a dispersbyk series manufactured by BYK-chemie. Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment.

  For the dispersion of the pigment, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, a paint shaker, or the like can be used.

  The solvent used for the second liquid B may be any liquid as long as it is a liquid, but is preferably an organic solvent, and particularly preferably a high-boiling organic solvent or a polymerizable compound. High boiling point organic solvents and polymerizable compounds may be used alone or in combination of two or more.

  The second liquid B is preferably prepared so as to have an sp value of 35 or less, and is preferably water-insoluble and adjusted to the properties of the oil-soluble organic solvent system. The aforementioned at least first droplet a1 can be suitably prepared in an organic solvent system containing a polymerizable or crosslinkable material, and when prepared in an organic solvent system, it can be easily mixed with the second liquid B, and It is possible to effectively avoid coalescence between the first droplet a1 and the droplet a2 which are ejected so as to contact and have an overlapping portion. Thereby, as described above, it is possible to effectively prevent the occurrence of blurring of the image and line width variations such as fine lines in the image.

  Adjustment of the sp value of the second liquid B can be suitably performed using a lipophilic solvent or the like. As one of the preferable adjustment modes, the lipophilic solvent may be contained in the range of 50% by mass or more and 100% by mass or less of the total mass of the second liquid B. When the content of the lipophilic solvent is within the above range, the sp value can be reduced and adjusted to a range of 35 or less. A preferred range for the sp value is 30 or less.

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

  The lipophilic solvent can be contained in the first liquid A described above with or without being contained in the second liquid B. Further, it may be contained in a liquid other than the second liquid B and the first liquid A.

Examples of the oleophilic solvent include high-boiling organic solvents and the aforementioned polymerizable materials, and high-boiling organic solvents are preferred.
Hereinafter, the high boiling point organic solvent suitable for the present invention will be mainly described.

  As the high-boiling organic solvent, (1) a viscosity at 25 ° C. of 100 mPa · s or less or a viscosity at 60 ° C. of 30 mPa · s or less and (2) a boiling point higher than 100 ° C. is preferable.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

] Or e-valent hydrocarbon groups linked together by an ether bond of carbon atoms from 4 to 24 (preferably 4 to 18) [for _{example, -CH 2 CH 2 OCH 2 CH} 2 -, - CH 2 CH 2 (OCH 2 _{CH 2) 3 -, - CH} 2 CH 2 CH 2 OCH 2 CH 2 CH 2 -,

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

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

Is preferred.

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

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

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

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

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

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

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

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

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

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

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

  The addition amount of the lipophilic solvent in the second liquid is preferably in the range of 50% by mass to 100% by mass, more preferably in the range of 70% by mass to 100% by mass, with respect to the total mass of the liquid, 90 A mass% or more and 100 mass% or less is particularly preferable.

  The second liquid B preferably contains a polymerization initiator. More preferably, it further contains a lipophilic solvent, and a colorant, a polymerizable material, and other components can be used as necessary. The details of the polymerizable material are as described above.

<Polymerization initiator>
The second liquid B can preferably contain at least one polymerization initiator. This polymerization initiator is a compound that generates a starting species such as a radical by applying energy of actinic light, heat, or both, and initiates, accelerates and cures a polymerization or crosslinking reaction of a polymerizable or crosslinkable material. .

  This polymerization initiator is preferably contained separately from the polymerizable material from the viewpoint of ensuring the storage stability of the first liquid A and the second liquid B described above. It is preferable to make it contain in 2nd liquid B other than the 1st liquid A containing material, and other liquids.

  As the polymerization initiator, a known photopolymerization initiator (including a radical generator), a thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, and the like can be selected and used.

  Examples of photopolymerization initiators (including radical generators) include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid Compounds, disulfonic acid compounds, onium salt compounds, and the like.

Preferable examples of the polymerization initiator include the following photopolymerization initiators.
For example, light of acetophenone derivative, benzophenone derivative, benzyl derivative, benzoin derivative, benzoin ether derivative, benzyldialkyl ketal derivative, thioxanthone derivative, acylphosphine oxide derivative, metal complex, p-dialkylaminobenzoic acid, azo compound, peroxide compound, etc. Examples of the polymerization initiator include acetophenone derivatives, benzyl derivatives, benzoin ether derivatives, benzyl dialkyl ketal derivatives, thioxanthone derivatives, and acylphosphine oxide derivatives. Among them, acetophenone derivatives, benzoin ether derivatives, benzyl dialkyl ketal derivatives, Acylphosphine oxide derivatives are particularly preferred.

Specific examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, benzophenone, p, p′-dichlorobenzophenone, p, p. '-Bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin-n-propyl ether, benzoin isobutyl ether, benzyldimethyl ketal, 1-hydroxy-cyclohexyl phenyl ketone, tetramethylthiuram monosulfide, thioxanthone , 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,2-dimethylpropioyl diphenylphosphine oxide, 2-methyl 2-ethylhexanoyldiphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6 -Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,3,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,3,6-trimethylbenzoyl) -phenylphosphine oxide, 2, 4,6-trimethoxybenzoyl-diphenylphosphine oxide, 2,4,6-trichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylnaphthyl phospho Chromatography, bis (eta ^{5-2,4-cyclopentadiene-1-yl)} - bis (2,6-difluoro-3-(1H-pyrrol-1-yl) - phenyl) titanium, p- dimethylaminobenzoic acid , P-diethylaminobenzoic acid, azobisisobutyronitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), benzoin peroxide, di-tert-butyl peroxide and the like.

  In addition to the above, examples of other preferable photopolymerization initiators include photopolymerization initiation described on pages 65 to 148 of “Ultraviolet curing system” by Kato Kiyomi (published by General Technology Center Co., Ltd .: 1989). An agent can be mentioned.

  The polymerization initiator preferably has excellent sensitivity. For example, it is not preferable to use one that causes thermal decomposition at a temperature of 80 ° C. or lower from the viewpoint of storage stability, and thermal decomposition occurs at a temperature up to 80 ° C. It is preferred to select a polymerization initiator that is not present.

  A polymerization initiator can be used 1 type or in combination of 2 or more types. Moreover, a well-known sensitizer can also be used together for the purpose of a sensitivity improvement in the range which does not impair the effect of this invention.

  The content of the polymerization initiator in the second liquid B is the maximum amount required for image formation of the first liquid A and the second liquid B from the viewpoint of stability over time, curability, and curing speed. When droplets are ejected onto the medium, the content is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and particularly preferably 3 to 10% by mass with respect to the polymerizable material applied per unit area. . When the content is too large, precipitation or separation with time may occur, or performance such as strength and rubbing resistance of the ink after curing may be deteriorated.

The polymerization initiator may be contained in the second liquid B and may be contained in the first liquid A described above. In this case, the storage stability of the first liquid A is maintained to a desired level. It can be appropriately selected and contained within a possible range.
Further, the polymerization initiator may be contained in the first liquid A described above without being contained in the second liquid B. In this case, the content in the first droplet is preferably 0.5 to 20% by mass and more preferably 1 to 15% by mass with respect to the polymerizable or crosslinkable compound in the first liquid A. .

<Colorant>
The first liquid A described above can contain at least one kind of colorant, and can be configured to record a monochromatic or multicolor visible image.
The colorant may be contained in the second liquid B other than the first liquid A or other liquids.

The colorant is not particularly limited, and can be appropriately selected from known water-soluble dyes, oil-soluble dyes, pigments, and the like. Among them, the first liquid A and the second liquid B according to the present invention are preferably composed of a water-insoluble organic solvent system from the viewpoint of the effect of the present invention, and are uniformly dispersed and dissolved in a water-insoluble medium. It is preferable to use oil-soluble dyes and pigments that are easily treated.
Hereinafter, the oil-soluble dye and pigment suitable for the present invention will be mainly described.

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

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

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

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

  When an oil-soluble dye is used as the colorant, the content of the oil-soluble dye in the first liquid A is preferably in the range of 0.05 to 20% by mass with respect to the total solid mass, 0.1 to 15 % By mass is more preferable, and 0.2 to 6% by mass is particularly preferable. Moreover, as content in each liquid of an oil-soluble dye in the case of containing an oil-soluble dye in the 2nd liquid B or another liquid, the range of 0-1 mass% is with respect to the total solid content mass. preferable.

~ Pigment ~
An embodiment using a pigment as the colorant is also preferable in that aggregation is likely to occur when a plurality of liquids are mixed. As the pigment, either an organic pigment or an inorganic pigment can be used, and as the black pigment, a carbon black pigment or the like is preferable. In general, pigments of three primary colors of black and cyan, magenta, and yellow are used, but other hues such as pigments having hues such as red, green, blue, brown, white, gold, silver, etc. Metal luster pigments, colorless or light extender pigments, and the like can also be used depending on the purpose.

  In addition, particles having silica, alumina, resin, or the like as a core material and having a dye or pigment fixed on the surface, an insoluble raked product of a dye, a colored emulsion, a colored latex, or the like can also be used as a pigment. Furthermore, resin-coated pigments can also be used. This is called a microcapsule pigment, and commercially available products such as those manufactured by Dainippon Ink and Chemicals and Toyo Ink are available.

  The volume average particle diameter of the pigment particles contained in the liquid is preferably in the range of 10 to 250 nm, more preferably 50 to 200 nm, from the viewpoint of balance between optical density and storage stability. Here, the volume average particle diameter of the pigment particles can be measured by a measuring device such as LB-500 (manufactured by HORIBA).

  When using a pigment as the colorant, the content of the pigment in the first liquid A is 0.1 to 20% by mass with respect to the total solid mass, from the viewpoint of optical density and stability during injection. The range is preferable, and the range of 1 to 10% by mass is more preferable. Moreover, as a content in each liquid of a pigment in the case of containing a pigment in the 2nd liquid B or another liquid, the range of 0-1 mass% is preferable with respect to the total solid content mass.

  The colorant may be used alone or in combination of two or more. Different colorants may be used for each droplet and liquid to be ejected, or the same colorant may be used.

In the present invention, as a preferred form,
(1) Form in which the first liquid A contains a polymerizable material and the second liquid B contains a polymerization initiator (2) The first liquid A contains a polymerizable material and a colorant, and the second liquid B (3) The first liquid A contains a polymerizable material and a colorant, and the second liquid B contains a polymerization initiator and a lipophilic solvent.
In the above, the polymerizable material may be contained in the first liquid A and may be contained in the second liquid B within a range that does not impair the effects of the present invention. In addition to being contained in the second liquid B, it may be contained in the first liquid A as long as the effects of the present invention are not impaired.

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

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

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

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

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

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

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

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

In addition to the above, each of the first liquid A and the second liquid B according to the present invention contains a pair of compounds that react by mixing to form aggregates or thicken, respectively. Can do. The set of compounds has a feature of rapidly forming aggregates or rapidly thickening the liquid, thereby more effectively suppressing coalescence between adjacent droplets. Can do.
Examples of the reaction of the set of compounds include an acid / base reaction, a hydrogen bonding reaction with a carboxylic acid / amide group-containing compound, a crosslinking reaction represented by boronic acid / diol, and a reaction by electrostatic interaction with a cation / anion. Etc.

(Relationship between surface tensions of first liquid A and second liquid B)
Before the droplet (I) made of the first liquid A containing at least a polymerizable compound is deposited on the recording medium, the droplet made of the second liquid B having a composition different from that of the first liquid A ( When an image is formed by applying II) to a wider area than the image formed by the droplets of the droplet (I), the recorded droplets are blurred or the droplet size is enlarged and the image is distorted May be obtained. Thus, in order to form an excellent image free from image disturbance due to bleeding or enlargement of the first liquid, the first liquid A and the second liquid B according to the present invention have the following conditions (A), It is preferable to satisfy all of (B) and (C).
In the following, a combination of at least one kind of first liquid A and at least one kind of second liquid B, which is used in the ink jet recording method of the present invention, is referred to as an “ink set for ink jet recording”. Sometimes.

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

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

(Condition (A))
In the present invention, as described above, in order to form a first liquid dot having a target size on a recording medium, the surface tension γs of the second liquid is any of the ink sets for ink jet recording. It is preferable to make it smaller than the surface tension γk of the first liquid.
Further, from the viewpoint of more effectively preventing expansion of the first liquid dot from landing to exposure, γs <γk-3 (mN / m) is more preferable, and γs <γk-5 (mN / m). Is particularly preferred.

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

(Conditions (B) and (C))
In the present invention, in order to form an ink dot of a desired size on a recording medium, the second liquid preferably contains at least one kind of surfactant. In this case, at least one of the surfactants contained in the second liquid preferably satisfies the following condition (B).
γs (0) −γs (saturation)> 1 mN / m Condition (B)
Furthermore, the surface tension of the second liquid preferably satisfies the following condition (C).
γs <(γs (0) + γs (saturation) ^maximum ) / 2 Condition (C)
Here, γs is the value of the surface tension of the second liquid. γs (0) is the value of the surface tension of the liquid component excluding all the surfactants in the second liquid. γs (saturation) is a liquid component that is saturated when one surfactant among the surfactants contained in the second liquid is added to the liquid component and the concentration of the surfactant is increased. This is the surface tension value. The γs (saturation) ^maximum is the maximum value among the γs (saturation) obtained for all the surfactants satisfying the condition (B) among the surfactants contained in the second liquid.

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

Hereinafter, the γs (0), γs (saturation), and γs (saturation) ^maximum will be specifically described.
For example, the component constituting the second liquid (Example 1) is a high boiling point solvent (diethyl phthalate, manufactured by Wako Pure Chemical Industries), a polymerization initiator (Irg907, manufactured by Ciba Specialty Chemicals Co., Ltd.), a fluorine-based surfactant. (Megafac F475, manufactured by Dainippon Ink & Chemicals, Inc.) and hydrocarbon surfactant (sodium di-2-ethylhexyl sulfosuccinate), γs (0), γs (saturated) ¹ (fluorine-based interface) When an activator is added), γs (saturated) ² (when a hydrocarbon-based surfactant is added), γs (saturated), and γs (saturated) ^maximum are as follows.

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

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

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

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

(Surfactant)
In the present invention, as described above, in order to form an ink dot having a target size on a recording medium, the second liquid preferably contains at least one surfactant.
In the present invention, the surfactant is hexane, cyclohexane, p-xylene, toluene, ethyl acetate, methyl ethyl ketone, butyl carbitol, cyclohexanone, triethylene glycol monobutyl ether, 1,2-hexanediol, propylene glycol monomethyl ether, isopropanol, It is a substance having strong surface activity against at least one solvent among methanol, water, isobornyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate, preferably hexane, toluene, propylene glycol monomethyl ether , Isobornyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate have strong surface activity against at least one solvent More preferably, it is a substance having strong surface activity against at least one kind of solvent among propylene glycol monomethyl ether, isobornyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate, and particularly preferable. Is a substance having a strong surface activity against at least one solvent among isobornyl acrylate, 1,6-hexane diacrylate, and polyethylene glycol diacrylate.

Whether or not a certain compound has a strong surface activity with respect to the solvents listed above can be determined by the following procedure.
(procedure)
One solvent is selected from the solvents listed above, and the surface tension γ (0) solvent of the solvent is measured. When the compound is added to the same solution as the solvent for which the γ (0) solvent was obtained, the concentration of the compound is increased by 0.01% by mass, and the change in the surface tension becomes 0.01 mN / m or less The surface tension γ (saturated) solvent of the solution is measured. The relationship between the γ (0) solvent and the γ (saturated) solvent is
γ (0) solvent-γ (saturated) solvent> 1 mN / m
If so, the compound is judged to be a substance having a strong surface activity with respect to the solvent.

  Specific examples of the surfactant contained in the second liquid include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers. , Nonionic surfactants such as acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, cationic surfactants such as alkylamine salts and quaternary ammonium salts, and fluorosurfactants. . In addition, examples of the surfactant include those described in JP-A Nos. 62-173463 and 62-183457.

  The above-described inkjet recording method of the present invention can be carried out in the so-called shuttle scan type inkjet recording apparatus shown in FIG. 8 in addition to the inkjet recording apparatus (so-called single pass system) of the present invention described later. Among these, the single pass method is preferable from the viewpoint of high speed. Since the single pass method will be described later, the shuttle scan method will be briefly described here. A shuttle scan type ink jet recording apparatus is known.

  FIG. 8 is a perspective view showing a main part of the shuttle scan type ink jet recording apparatus. In FIG. 8, the direction orthogonal to the transport direction of the recording medium 16 is a main scanning direction (represented by an arrow M), and the transport direction of the recording medium 16 is a sub-scanning direction (represented by an arrow S).

  As shown in FIG. 8, a carriage 15 on which a droplet ejection head (K ink, Y ink, M ink, C ink, Ws ink (white ink)) is mounted is positioned above the recording medium 16, and this carriage 15 is It is configured to be able to reciprocate in the main scanning direction M. On the downstream side of the carriage 15 in the sub-scanning direction, a UV light source 27 is disposed in a state where the irradiation unit faces the recording medium 16. Further, the recording medium 16 is configured to be conveyed at a predetermined pitch in the sub scanning direction S by a sub scanning mechanism (not shown).

  During recording, the recording medium 16 is conveyed at a predetermined pitch in the sub-scanning direction S by the sub-scanning mechanism. The droplet ejection head mounted on the carriage 15 ejects droplets from a nozzle (not shown) to the recording medium 16 while moving in the main scanning direction M by a main scanning mechanism (not shown). An image is recorded with a predetermined bandwidth.

  When one movement of the carriage 15 in the main scanning direction is completed, the recording medium 16 is transported at a predetermined pitch in the sub-scanning direction S, and the carriage 15 is moved again in the main scanning direction M while the predetermined bandwidth is reached. The image is recorded with. By repeating such an operation a plurality of times, an image based on the image data is recorded on almost the entire surface of the recording medium 16.

As described above, after recording with droplets from the droplet ejection head mounted on the carriage 15, the recording medium 16 is conveyed, and the recorded image moves directly below the UV light source 27 and is exposed by the UV light source 27. The image is cured.
It is also known that a UV light source is mounted on the carriage, and exposure is performed immediately after the droplet is ejected during scanning of the carriage. In the ink jet recording method of the present invention, the second liquid B is used. Since it is necessary to maintain the surface of the second liquid B, which has been deposited, in a liquid state between the time when the first liquid A is deposited and the time when the first liquid A is deposited, such a configuration is not suitable.

<Inkjet recording apparatus>
The above-described ink jet recording method of the present invention is preferably carried out by the ink jet recording apparatus of the present invention described below.
The ink jet recording apparatus of the present invention is disposed on the downstream side in the transport direction of the recording medium with respect to the transporting means for transporting the recording medium, the liquid applying unit for applying liquid to the recording medium, and the liquid applying unit. An energy applying unit that applies active energy to the liquid applied on the recording medium; and a control unit that controls the transport unit and the energy applying unit while discharging the liquid from the liquid applying unit. The liquid application unit includes a line-type droplet ejection head that is disposed in a direction orthogonal to a conveyance direction of the recording medium to be conveyed and has a length corresponding to the entire width of the recordable area of the recording medium. A plurality of droplet ejection heads, and as the plurality of droplet ejection heads, a droplet ejection head that ejects droplets of the first liquid A containing a polymerizable or crosslinkable material for forming an image, and the first liquid A and A droplet ejection head for ejecting droplets of the second liquid B, which is a white ink containing a white pigment and having a different composition, and the droplet ejection head for ejecting the second liquid B; A droplet ejection head that discharges one liquid A and an energy applying unit are arranged in order from the upstream side in the transport direction of the recording medium.
The ink jet recording apparatus of the present invention is a so-called single-pass ink jet recording apparatus, and includes a droplet ejection head that discharges the second liquid B in order from the upstream side in the transport direction of the recording medium, and the first liquid A. Since the droplet ejection head for discharging and the energy applying means are arranged, the second droplet that has been ejected between the time when the second liquid B is applied and the time when the first liquid A is ejected is provided. The surface of the liquid B can be maintained in a liquid state.

  Next, with reference to FIGS. 1-6, the preferable aspect of the inkjet recording device of this invention is demonstrated. FIG. 1 is an overall configuration diagram of an example of an ink jet recording apparatus 10. The ink jet recording apparatus 10 applies at least two types of liquid, a first liquid A containing at least a polymerizable or crosslinkable material, and a second liquid B, which is a white ink containing a white pigment, to a recording medium 16. The desired image is formed on the recording medium 16 by applying. In the following description, the first liquid A is referred to as a recording liquid, and the second liquid B is referred to as a white processing liquid.

In FIG. 1, an ink jet recording apparatus 10 includes a liquid applying unit 12 that applies a recording liquid and a white processing liquid to a recording medium 16 by ejecting the liquid.
The ink jet recording apparatus 10 also includes a liquid storage / loading unit 14 that stores recording liquid and white processing liquid supplied to the liquid applying unit 12, a paper feeding unit 18 that supplies the recording medium 16, and a recording medium. A decurling unit 20 that removes curl 16, a belt conveyance unit 22 that is disposed to face the ejection surface of the liquid application unit 12, and conveys the recording medium 16 while maintaining the flatness of the recording medium 16; An image detection unit 24 that reads an image as a result of ink droplet ejection by the liquid application unit 12 (in an ink droplet landing state) and a paper discharge unit 26 that discharges a recorded recording medium to the outside.

  In FIG. 1, as an example of the paper supply unit 18, one that feeds roll paper (continuous paper) is shown. However, as shown in FIG. 7, one that feeds cut paper that has been cut in advance is used. May be. In the case of an apparatus configuration that uses roll paper, a cutter 28 is provided. Incidentally, the recording medium 16 delivered from the paper supply unit 18 generally retains curl and curls. In order to remove this curl, heat is applied to the recording medium 16 by the heating drum 30 in the direction opposite to the curl direction in the decurling unit 20. After the decurling process, the cut recording medium 16 is sent to the belt conveyance unit 22.

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

The liquid applicator 12 and its peripheral portion of the ink jet recording apparatus 10 are shown in the plan view of FIG.
In FIG. 2, the liquid application unit 12 ejects the white processing liquid droplet ejection head 12 </ b> Ws for ejecting the white processing liquid onto the recording medium 16 in a single pass, and the droplets on the recording medium 16 in a single pass. The recording liquid droplet ejection heads 12C, 12M, 12Y, and 12K are configured. Specifically, a line-type head having a length corresponding to the entire recordable width of the recording medium 16 is perpendicular to the medium transport direction (the sub-scanning direction indicated by arrow S in FIG. 2) (main scanning direction). ) Is a so-called full-line type head.

Each of the droplet ejection heads 12Ws, 12C, 12M, 12Y, and 12K in this example has a plurality of nozzles (liquid ejection ports) over a length exceeding at least one side of the maximum size recording medium 16 targeted by the inkjet recording apparatus 10. Are arranged.
Further, from the upstream side (the right side in FIG. 2) along the medium transport direction S, the white processing liquid (Ws), the cyan recording liquid (C), the magenta recording liquid (M), and the yellow recording liquid. The droplet ejection heads 12Ws, 12C, 12M, 12Y, and 12K corresponding to the respective liquids are arranged in the order of (Y) and the black recording liquid (K), and a color image can be formed on the recording medium 16. .

  Specifically, first, the white processing liquid droplet (II) is applied onto the recording medium 16 by the white processing liquid being ejected from the droplet ejection head 12 Ws for the white processing liquid toward the recording medium 16. Next, the recording liquid droplets (I) are directed from the recording liquid droplet ejection heads 12C, 12M, 12Y, and 12K toward the recording medium 16 so as to overlap the region to which the liquid droplets (II) have been applied. Is ejected.

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

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

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

The UV light source (energy applying means) 27 irradiates the recording medium 16 with ultraviolet rays in order to cure the ink containing the polymerizable compound. A known light source such as a high pressure mercury lamp, a medium pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, a xenon lamp, a carbon arc lamp, an ultraviolet fluorescent lamp, an ultraviolet LED, an ultraviolet LD, etc. can be used as the ultraviolet light source. From the viewpoint of properties, it is preferable to use a high-pressure mercury lamp or a metal halide lamp. The UV light source preferably has a light amount peak in the wavelength range of 200 nm to 400 nm, and preferably has an irradiation light amount in the range of 1 to 500 mJ / cm ^{2 at} the light amount peak wavelength. The UV light source preferably uses a cold mirror for the reflector and an infrared cut glass for the cover glass to prevent a temperature rise of the recording medium due to heat ray irradiation. Although omitted in FIG. 2, in the case of ink containing a radical polymerizable compound, the ink is cured and fixed better by replacing the curing atmosphere of the UV irradiation part with an inert gas (such as nitrogen). be able to.

  The liquid storage / loading unit 14 shown in FIG. 1 has a white processing liquid tank for storing a white processing liquid and a liquid tank for storing ink for each color of YMCK, and each droplet ejection via a pipe line (not shown). The heads 12Ws, 12C, 12M, 12Y, and 12K are communicated with each other.

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

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

[Structure of droplet ejection head]
FIG. 3A shows a basic overall structure of the droplet ejection head 50 by adding a reference numeral 50 to the droplet ejection head representing the droplet ejection heads 12Ws, 12C, 12M, 12Y, and 12K shown in FIG. It is a plane perspective view which shows an example.

  The droplet ejection head 50 shown as an example in FIG. 3A is a so-called full-line type head, and is a direction (in the drawing) orthogonal to the conveyance direction of the recording medium 16 (the sub-scanning direction indicated by the arrow S in the drawing). In a main scanning direction indicated by an arrow M), two or more nozzles 51 (liquid ejection ports) that eject liquid toward the recording medium 16 are two-dimensionally formed over a length corresponding to the width Wm of the recording medium 16. It has an arrayed structure.

  The droplet ejection head 50 includes a nozzle 51, a pressure chamber 52 communicating with the nozzle 51, and a plurality of pressure chamber units 54 including a liquid supply port 53 in a predetermined manner with respect to the main scanning direction M and the main scanning direction M. They are arranged along two oblique directions forming an acute angle θ (0 degree <θ <90 degrees). In FIG. 3A, only a part of the pressure chamber units 54 is shown for convenience of illustration.

  Specifically, the nozzles 51 are arranged at a constant pitch d in an oblique direction that forms a predetermined acute angle θ with respect to the main scanning direction M, and thus, “on a straight line along the main scanning direction M” d × cos θ ”can be handled equivalently.

  FIG. 3B shows a cross-sectional view taken along the line bb in FIG. 3A for the pressure chamber unit 54 described above as one ejection element constituting the droplet ejection head 50.

As shown in FIG. 3B, each pressure chamber 52 communicates with a common liquid chamber 55 through a liquid supply port 53. The common liquid chamber 55 communicates with a tank which is a liquid supply source (not shown), and the liquid supplied from the tank is distributed and supplied to each pressure chamber 52 via the common liquid chamber 55.
A piezoelectric body 58a is disposed on the diaphragm 56 constituting the top surface of the pressure chamber 52, and an individual electrode 57 is disposed on the piezoelectric body 58a. The diaphragm 56 is grounded and functions as a common electrode. These diaphragm 56, individual electrode 57 and piezoelectric body 58a constitute a piezoelectric actuator 58 as means for generating a liquid ejection force.

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

  FIG. 3A shows an example in which a plurality of nozzles 51 are two-dimensionally arranged as a structure capable of forming a high-resolution image on the recording medium 16 at high speed. The droplet ejection head is not particularly limited to a structure in which a plurality of nozzles 51 are two-dimensionally arranged, and may have a structure in which a plurality of nozzles 51 are one-dimensionally arranged. Further, the pressure chamber unit 54 shown in FIG. 3B as an ejection element constituting the droplet ejection head is an example, and is not particularly limited to such a case. For example, instead of disposing the common liquid chamber 55 below the pressure chamber 52 (that is, the discharge surface 50a side than the pressure chamber 52), the common liquid is disposed above the pressure chamber 52 (that is, opposite to the discharge surface 50a). The chamber 55 may be disposed. Further, for example, instead of using the piezoelectric body 58a, a liquid discharge force may be generated using a heating element.

In addition to the droplet ejection heads 12Ws, 12C, 12M, 12Y, and 12K, a white ink droplet ejection head 12W may be provided on the downstream side of the droplet ejection heads 12C to 12K. The droplet ejection head 12W is a droplet ejection head that ejects the third liquid C described above. FIG. 4A is a diagram showing the form. In FIG. 4, the same components as those in FIG. This form is useful, for example, when an image is recorded on a transparent recording medium and the image is observed from a surface opposite to the image recording surface. That is, when recording an image on a transparent recording medium, the droplet ejection heads 12W, 12C, 12M, 12Y, and 12K are used instead of the droplet ejection heads 12Ws, and the droplet ejection heads 12C, 12M, 12Y, and By applying white ink by the droplet ejection head 12W after droplet ejection by 12K, a sufficient reflection density can be obtained when an image is observed from the side opposite to the image recording surface.
The preferred composition and preferred white pigment of the third liquid C are the same as those of the second liquid B.

  In the present invention, as means for applying the white processing liquid onto the recording medium, other means such as coating may be used in addition to the means for discharging the white processing liquid from the nozzle. FIG. 4B shows a form in which the white treatment liquid is applied by coating. In this configuration, instead of the droplet ejection head 12Ws in the configuration of FIG. 2, a coating mechanism 13Ws is provided on the upstream side in the transport direction, and the white treatment liquid is applied by the coating mechanism 13Ws, and then the droplet ejection head 12C. It is transported directly under ~ 12K. Other configurations are the same as those in FIGS.

  There is no restriction | limiting in particular as an apparatus used for the said application | coating, A well-known coating apparatus can be suitably selected according to the objective. Examples include air doctor coaters, blade coaters, lot coaters, knife coaters, squeeze coaters, impregnation coaters, reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, extrusion coaters, etc. It is done.

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

  Further, the inkjet recording apparatus 10 includes a cap 64 as a means for preventing the meniscus from drying of the nozzle 51 during the long discharge pause period or preventing a rise in viscosity near the meniscus, and a cleaning as a means for cleaning the discharge surface 50a. A blade 66 is provided.

  The maintenance unit including the cap 64 and the cleaning blade 66 can be moved relative to the droplet ejection head 50 by a moving mechanism (not shown), and can be moved from a predetermined retraction position to a position below the droplet ejection head 50 as necessary. It is moved to the maintenance position.

Further, the cap 64 is moved up and down relatively with respect to the droplet ejection head 50 by a lifting mechanism (not shown). The elevating mechanism raises the cap 64 to a predetermined ascending position and contacts the droplet ejection head 50 to cover at least the nozzle region of the ejection surface 50a with the cap 64.
Preferably, the inside of the cap 64 is divided into a plurality of areas corresponding to the nozzle rows by a partition wall, and each of the partitioned areas can be selectively sucked by a selector or the like.

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

  The suction pump 67 sucks the liquid from the nozzle 51 of the droplet ejection head 50 in a state where the discharge surface 50 a of the droplet ejection head 50 is covered with the cap 64, and sends the sucked liquid to the recovery tank 68.

  Such a suction operation is stopped for a long time, when the liquid tank 60 is loaded in the ink jet recording apparatus 10 and liquid is filled from the liquid tank 60 to the droplet ejection head 50 (at the time of initial filling), and the viscosity is increased by stopping for a long time. It is also performed when removing the liquid (when starting to use for a long time).

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

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

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

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

The liquid application unit 12, the image detection unit 24, and the UV light source 27 are the same as those described in FIG. 1 and have already been described.
The communication interface 110 is an image data input unit that receives image data transmitted from the host computer 300. As the communication interface 110, a wired or wireless interface such as USB (Universal Serial Bus) or IEEE1394 can be applied. The image data input to the inkjet recording apparatus 10 via the communication interface 110 is temporarily stored in the first memory 114 for storing image data.

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

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

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

  The medium type detection unit 132 detects the type of the recording medium. There are various detection modes for the type of recording medium. For example, a mode in which a sensor is provided in the paper feed unit 18 in FIG. 1, a mode in which the sensor is input by a user operation, a mode in which the sensor is input from the host computer 300, and an image input from the host computer 300 There is a mode in which data (for example, resolution and color) or additional data of the image data is automatically detected by analyzing the data.

  The ink type detection unit 134 detects the type of ink. There are various types of ink type detection modes. For example, a mode in which a sensor is provided in the liquid storage / loading unit 14 in FIG. 1, a mode in which the liquid is input by a user operation, a mode in which the liquid is input from the host computer 300, and a mode in which the data is input from the host computer 300 There is a mode in which image data (for example, resolution and color) or additional data of the image data is automatically detected by analysis.

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

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

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

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

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

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

  The print control unit 150 also detects the liquid film formed on the recording medium by the white processing liquid based on the medium type detected by the medium type detection unit 132 and the ink type detected by the ink type detection unit 134. The thickness of the liquid film is switched by determining the thickness and controlling the droplet deposition amount of the white processing liquid using the head driver 154.

The print controller 150 is accompanied by a second memory 152, and droplet ejection data and the like are temporarily stored in the second memory 152 during image processing in the print controller 150.
In FIG. 6, the second memory 152 is shown in a form associated with the print control unit 150, but it can also be used as the first memory 114. Also possible is an aspect in which the print controller 150 and the system controller 112 are integrated and configured with one processor.

  The head driver 154 applies the droplet ejection data provided from the print control unit 150 (actually, the droplet ejection data stored in the second memory 152) to each droplet ejection head 50 constituting the liquid application unit 12. On the other hand, an ejection drive signal is output. The ejection drive signal output from the head driver 154 is applied to each droplet ejection head 50 (specifically, the actuator 58 shown in FIG. 3B), so that the droplet ejection head 50 is directed toward the recording medium. Liquid (droplet) is discharged.

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

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

[Example 1]
<Preparation of white pigment dispersion W-1>
Mixing 16g of titanium oxide (JR-805 manufactured by Teica Co., Ltd.), 60.8g of 1,6-hexanediol diacrylate (HDODA; manufactured by Daicel Cytec Co., Ltd.), and 3.2g of BYK-111 (manufactured by BYK Chemie) And stirred with a stirrer for 1 hour. The mixture after stirring was dispersed with an Eiger mill to obtain pigment dispersion W-1.
Here, dispersion conditions were such that zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 1 hour.

<Preparation of Inkjet Recording Liquids I-1 and I-2 Containing White Pigment>
Ingredients having the following composition were stirred, mixed, and dissolved to prepare inkjet recording liquid I-1 (second liquid B). The sp value of the inkjet recording liquid I-1 was 20, and the surface tension was 23 mN / m.
・ Pigment dispersion W-1 ... 9g
・ 1,6 hexanediol diacrylate (polymerizable compound) 2.7g
(HDODA; manufactured by Daicel Cytec Co., Ltd.)
・ The following polymerization initiator-1
(Irg907, manufactured by Ciba Specialty Chemicals)… 1.5g
-The following sensitizer-1
(Darocur ITX, manufactured by Ciba Specialty Chemicals)… 0.75g
-The following sensitizer-2
(Darocur EDB, manufactured by Ciba Specialty Chemicals)… 0.75g
・ Megafac F475 (Dainippon Ink Chemical Co., Ltd.) ... 0.3g

  As described above, the sp value was calculated by the sp value calculation program by R.L.smith (Tohoku University) (25 ° C.). The same applies hereinafter. However, the compound containing no carbon atom was excluded from the calculation, and the structural unit such as a polymer or polyethylene chain was a saturated repeating unit having a bond, and water was calculated as 47.8.

  Further, F475 was removed from the inkjet recording liquid I-1, and the equivalent amount was replaced with HDODA to prepare an inkjet recording liquid I-2. The SP value of the inkjet recording liquid I-2 was 20, and the surface tension was 32 mN / m.

<Preparation of Pigment Dispersion P-1>
16 g of PB15: 3 (IRGALITE BLUE GLO; manufactured by Ciba Specialty Chemicals Co., Ltd.), 48 g of 1,6-hexanediol diacrylate (HDODA; manufactured by Daicel Cytec Co., Ltd.), and 16 g of BYK-168 (manufactured by BYK Chemie) Mix and stir with a stirrer for 1 hour. The mixture after stirring was dispersed with an Eiger mill to obtain pigment dispersion P-1.
Here, dispersion conditions were such that zirconia beads having a diameter of 0.65 mm were filled at a filling rate of 70%, the peripheral speed was 9 m / s, and the dispersion time was 1 hour.

<Preparation of Inkjet Recording Liquid II-1 Containing Pigment>
Ingredients having the following composition were stirred, mixed, and dissolved to prepare inkjet recording liquid I-1 (first liquid A). The sp value of Inkjet Recording Liquid II-1 was 20, and the surface tension was 32 mN / m.
・ Pigment dispersion P-1: 3.75 g
・ 1,6-hexanediol diacrylate (polymerizable compound): 11.25 g
(HDODA; manufactured by Daicel Cytec Co., Ltd.)

<Preparation of Inkjet Recording Liquid III-1 Containing No Pigment>
Inkjet recording liquid III-1 was prepared by stirring, mixing and dissolving the components having the following composition. The sp value of Inkjet Recording Liquid III-1 was 20, and the surface tension was 23 mN / m.
・ 1,6-hexanediol diacrylate (polymerizable compound): 11.7 g
(HDODA; manufactured by Daicel Cytec Co., Ltd.)
・ Polymerization initiator-1 1.5g
(Irg907, manufactured by Ciba Specialty Chemicals Co., Ltd.)
・ Sensitizer-1 0.75g
(Darocur ITX Ciba Specialty Chemicals Co., Ltd.)
・ Sensitizer-2 ... 0.75g
(Darocur EDB, manufactured by Ciba Specialty Chemicals)
・ Megafuck F475 ... 0.3g
(Dainippon Ink Chemical Co., Ltd.)

<Preparation of Comparative Inkjet Recording Liquid II-0 Containing Pigment>
Inkjet recording liquid II-0 was prepared by stirring, mixing and dissolving the components having the following composition. The sp value of Inkjet Recording Liquid II-0 was 20, and the surface tension was 32 mN / m.
-The above-mentioned pigment dispersion P-1 ... 3.75 g
・ 1,6-hexanediol diacrylate (polymerizable compound): 8.25 g
(HDODA; manufactured by Daicel Cytec Co., Ltd.)
・ Polymerization initiator-1 1.5g
(Irg907, manufactured by Ciba Specialty Chemicals Co., Ltd.)
・ Sensitizer-1 0.75g
(Darocur ITX, manufactured by Ciba Specialty Chemicals)
・ Sensitizer-2 ... 0.75g
(Darocur EDB, manufactured by Ciba Specialty Chemicals)

<Image recording and evaluation>
(Image recording method 1)
Prepared inkjet recording liquid I-1 and liquid II-1 using inkjet printer (Toshiba tech head (CA3) mounted jig: droplet ejection frequency: 4.8 KHz, number of nozzles: 318, nozzle density 150 npi (nozzle per inch) drop size 2 heads that can be varied in 7 steps from 6 pl to 42 pl, load 4 sets of 300 npi headsets) and eject each ink from the 2 headsets (42 pl). Draw uniformly. At this time, a polyethylene terephthalate (PET) sheet (trade name: PPL / Xerox film for laser printers, manufactured by Fuji Xerox Co., Ltd .; hereinafter referred to as PET sheet) having a thickness of 60 μm was used as a recording medium.

  The discharge order was liquid I-1 → liquid II-1, and the droplet ejection interval when droplets were ejected between liquid I-1 and liquid II-1 was 400 milliseconds. At this time, the transport speed is adjusted so that the liquid I-1 has an adjacent droplet (first liquid) so that the overlapping ratio between the adjacent droplets is 5%. The overlap ratio between the droplet a1 and the first droplet a2) was set to 50%.

  In addition, as described above, the overlap rate is 100 × (2b−c) / (2b), where b represents the radius of a droplet after one second is deposited and b represents the interval between adjacent droplets. %].

After the ejection, the image was fixed by irradiating with a metal halide lamp at a wavelength of 365 nm with an ultraviolet ray amount of ~ 500 mJ / cm ² . Irradiation was performed 1 second after II-1 droplet ejection.

  Further, the liquid II-1 was ejected in the form of a line. Also in this case, the overlapping rate between adjacent droplets (the first droplet a1 and the first droplet a2) was set to 50%.

  Further, a lattice-like pattern was drawn with the liquid II-1. Also in this case, the overlapping rate between adjacent droplets (the first droplet a1 and the first droplet a2) was set to 50%. As the lattice pattern, 80 μm lines were drawn at 240 μm intervals.

(Image recording method 2)
Similar image formation was performed with respect to the image recording method 1 except that the liquid I-1 was replaced with III-1.

(Image recording method 3)
In addition, II-1 was replaced with II-0 in the image recording method 1, and the same image formation was performed except that I-1 was not used.

The image recording method 1 was exposed after I-1 droplet ejection, and the image recording method 2 was exposed immediately after III-1 droplet ejection. Exposure amount was ^{500mJ / cm 2, 30mJ / cm} 2. Although when exposed at 500 mJ / cm ² was cured, when exposed at 30 mJ / cm ^2, sufficient curing although increase in viscosity was observed was observed.

The following evaluation was performed, and the evaluation results are shown in Table 1.
-1. Evaluation of line quality
The liquid I and liquid II were overlaid in a line shape, and the quality of the line was evaluated according to the following evaluation criteria. However, only one liquid was ejected in a line form as the liquid I-0 for ink jet recording.
<Evaluation criteria>
A: The dot shape was maintained and a uniform line shape was obtained.
A ′: The dot shape is not maintained, but a uniform line shape is obtained.
B: There was no independence of each dot, and disturbance of the line width due to coalescence between adjacent droplets was observed in some places.
C: There was no independence of each dot, and disturbance of the line width due to coalescence between adjacent droplets as a whole was recognized.

-2. Line Width The width of the drawn line image was measured with a dot analyzer DA6000 (manufactured by Oji Scientific Instruments).

-3. Reflection density
The reflection density was visually observed.
<Evaluation criteria>
A: The density is felt to be sufficient B: The density is felt light C: The density is felt very light

-4. Evaluation of lattice distortion
The lattice distortion was evaluated.
<Evaluation criteria>
A: Good image quality without distortion.
B: Distortion resulting from line disturbance has occurred.
C: The undropped portion of the lattice is narrowed by 10% or more and 30% or less than the set value.
D: The undropped portion of the lattice is narrowed by 30% or more than the set value.

-5. Evaluation of stickiness −
Immediately after UV irradiation, the image surface (recording surface) was touched with a finger and evaluated according to the following evaluation criteria.
<Evaluation criteria>
A: There was no stickiness.
B: Some stickiness was recognized.
C: Significant stickiness was recognized.

-6. Evaluation of scratch resistance
The PET sheet and art paper on which a line-shaped image was recorded were observed for changes when the image was rubbed 10 times with an eraser after 30 minutes had passed after UV irradiation, and evaluated according to the following evaluation criteria.
<Evaluation criteria>
A: There was no decrease in density due to abrasion.
B: A slight decrease in density due to rubbing was observed.
C: The concentration was remarkably reduced by rubbing.

-7. Evaluation of light resistance
A PET sheet on which a line-shaped image is recorded is irradiated with xenon light (85,000 Lux) using a weather meter (Atlas C.I65) for one week, and the density before and after irradiation is measured with a microdensitometer (model name). : MICRO-PHOTOMETER MPM-No. 172, manufacturer name: manufactured by Union Optical Co., Ltd.) to obtain a dye residual ratio [%], and evaluated in 5 stages according to the following evaluation criteria.
<Evaluation criteria>
A: The pigment residual ratio was 90% or more.
B: Dye remaining rate was 89-80%.
C: The pigment residual ratio was 79 to 70%.
D: Dye residual ratio was 69 to 50%.
E: Dye remaining rate was less than 49%.

-8. Evaluation of ozone resistance
A PET sheet on which a line-shaped image was recorded was stored for 1 week under an ozone concentration of 5.0 ppm, and the concentration of the image before and after storage was measured using a microdensitometer (model name: MICRO-PHOTOMETER MPM-No. Name: Union Optical Co., Ltd.) to obtain a dye residual ratio (%), and evaluated in five stages according to the following evaluation criteria. The ozone resistance was evaluated only for the image on the PET sheet.
<Evaluation criteria>
A: The pigment residual ratio was 90% or more.
B: Dye remaining rate was 89-80%.
C: The pigment residual ratio was 79 to 70%.
D: Dye residual ratio was 69 to 50%.
E: Dye remaining rate was less than 49%.

  As shown in Table 1, a sufficient reflection density is obtained when the second liquid B according to the present invention is used, whereas a sufficient density is obtained when the second liquid B is not used. Absent. Further, when the second liquid B according to the present invention is used, good line quality can be obtained, and both the line quality and the concentration can be achieved only by using this liquid. However, when the liquid B of the present invention is used, the effects (line quality, film quality) of the present invention cannot be obtained when the liquid B is sufficiently cured while droplets such as I-1 and II-1 are ejected. I understand.

[Example 2]
For Example 1, the liquid used is III-1, II-1, and I-2, and the droplet ejection order is III-1 → II-1 → I-2. Evaluated droplet ejection in the same manner as in Example 1. In this case, however, the surface was observed from the surface opposite to the surface on which the droplets were deposited. The results are shown in Table 2.

  It can be seen that good line quality, concentration, film quality and the like can be obtained even when such a three-liquid system is used. In this way, the present invention is also effective when observing from the back side.

Example 3
In the same manner as in Example 1 except that HDODA (manufactured by Daicel Cytec Co., Ltd.) was replaced with an equal mass of the high-boiling organic solvent S-32 when liquid I-1 was prepared in Example 1. Liquid IV-1 was prepared, image recording was performed, and line quality and lattice distortion were evaluated. In this example, the same results as in Example 1 were obtained.

Example 4
In the same manner as in Example 2, except that HDODA (manufactured by Daicel Cytec Co., Ltd.) used in the preparation of Liquid III-1 in Example 2 was replaced with an equal mass of the above high-boiling organic solvent S-32. Then, liquid V-1 was prepared, image recording was performed, and line quality and lattice distortion were evaluated. In this example, the same result as in Example 2 was obtained.

1 is an overall configuration diagram illustrating an example of an inkjet recording apparatus of the present invention. It is a top view which shows a liquid provision part and its peripheral part. (A) is a plane perspective view which shows an example of the fundamental whole structure of a droplet ejection head, (b). It is sectional drawing along the bb line in (a). It is a figure which shows the form different from FIG. 2 which shows a liquid provision part and its peripheral part. It is the schematic which showed the structure of the liquid supply system in an inkjet recording device. It is a principal block diagram showing the system configuration of the ink jet recording apparatus. It is a figure which shows the form different from FIG. 2 which shows a liquid provision part and its peripheral part. It is a figure which shows the principal part of the inkjet recording apparatus of a shuttle scan system.

Explanation of symbols

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

Claims (12)

In an inkjet recording method for recording a desired image by ejecting a first liquid A onto a recording medium with at least a first droplet a1 and a droplet a2.
The first liquid A contains a polymerizable or crosslinkable material for forming the image, and the droplet a1 and the droplet a2 are overlapped with an overlapping ratio of 10% or more and 90% or less. The second liquid B, which is a white ink containing a white pigment and having a composition different from that of the first liquid A, is the same as or more than the image formed with the first liquid A. even leave granted in advance the recording medium in a wide range, during the period from by applying a second liquid B until the first liquid a ejects droplets, the applied surface of the second liquid B An ink jet recording method comprising maintaining a liquid state. 2. The ink jet recording method according to claim 1, wherein an overlapping ratio in an overlapping portion between the droplet a <b> 1 and the droplet a <b> 2 is 30% to 70% .   3. The ink jet recording method according to claim 1, wherein the second liquid B includes at least a polymerization initiator that causes a crosslinking reaction of the polymerizable or crosslinkable material in the first liquid A. 4.   The said 2nd liquid B contains a lipophilic solvent, Content of this lipophilic solvent is 50 mass% or more of the total mass of the said 2nd liquid B, Any one of Claim 1 to 3 characterized by the above-mentioned. The ink jet recording method according to claim 1.   5. The ink jet recording method according to claim 4, wherein the lipophilic solvent is a high boiling point organic solvent having a boiling point higher than 100.degree.   The inkjet recording method according to claim 1, wherein the first liquid A further contains a colorant.   7. The droplet ejection interval from when the second liquid B is applied to when the first droplet a <b> 1 is ejected is set to 5 μs or more and 400 ms or less. 7. The inkjet recording method according to item.   8. The ink jet recording method according to claim 1, wherein a droplet size of the first droplet a <b> 1 and the droplet a <b> 2 is 0.1 picoliter or more and 100 picoliter or less. .   9. The inkjet according to claim 1, wherein after the first droplet a <b> 1 is ejected, active energy is applied to the image to polymerize or crosslink the polymerizable or crosslinkable material. Recording method. Conveying means for conveying a recording medium;
A liquid application unit for applying a liquid to the recording medium;
An energy applying unit that is disposed on the downstream side in the transport direction of the recording medium from the liquid applying unit, and applies active energy to the liquid applied on the recording medium;
Control means for controlling the conveying means and the energy applying means while discharging liquid from the liquid applying section;
The liquid application unit is provided with a plurality of line-type droplet ejection heads arranged in a direction orthogonal to the conveyance direction of the recording medium to be conveyed and having a length corresponding to the entire width of the recordable area of the recording medium. And
As the plurality of droplet ejection heads, a droplet ejection head that ejects droplets of the first liquid A containing a polymerizable or crosslinkable material for forming an image is different in composition from the first liquid A, And a droplet ejection head that ejects droplets of the second liquid B, which is white ink containing a white pigment,
A droplet ejection head for ejecting the second liquid B, a droplet ejection head for ejecting the first liquid A, and the energy application means, are disposed in order from the upstream side in the transport direction of the recording medium, according to claim 1 An ink jet recording apparatus, which is used for the ink jet recording method according to any one of items 1 to 9 .   And a droplet ejection head that ejects droplets of the third liquid C that is white ink containing at least one type of white pigment, the surface tension γ3 of the third liquid C, and the second liquid B. The ink jet recording apparatus according to claim 10, wherein the relationship of the surface tension γ2 is γ2 <γ3-3 (mN / m).   Instead of the droplet ejection head that discharges the droplet of the second liquid B, a liquid application unit that applies the second liquid B is provided upstream of the liquid application unit in the conveyance direction of the recording medium. An ink jet recording apparatus according to claim 10 or 11, wherein:

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