JP2017074729A - Maintenance method for inkjet recording device and inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a maintenance method for an ink jet recording device being capable of improving image quality and durability of a recording image obtained while securing intermittent discharge stability of ink and reaction liquid, and the ink jet recording device.SOLUTION: A maintenance method for an ink jet recording device comprises a maintenance step of performing preliminary discharge for discharging droplets of reaction liquid and droplets of a clear ink composition containing resin from an ink jet head to a recording medium and bringing them into contact with one another in the ink jet recording device discharging a coloring ink composition containing a color material and the reaction liquid containing a reagent agglutinating or thickening components of the ink composition from the ink jet head and performing recording onto the recording medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a maintenance method for an ink jet recording apparatus and an ink jet recording apparatus that performs the maintenance method.

  Conventionally, an inkjet recording method for recording an image on a recording medium by ejecting minute ink droplets from a nozzle of a recording head of an inkjet recording apparatus is known, and use in a sign printing field and a high-speed label printing field is also examined. Has been. When an image is recorded on a recording medium with low ink absorption (for example, art paper or coated paper) or non-ink-absorbing recording medium (for example, plastic film), the ink is used as the global environment and the human body. From the viewpoint of safety, etc., use of a water-based resin ink composition containing a resin emulsion has been studied.

  Here, when recording on an ink low (non) absorbent recording medium using an aqueous resin ink composition (hereinafter also referred to as “ink”), a reaction liquid may be used to suppress ink bleeding. When the reaction liquid is ejected by inkjet, the reaction is performed in the same way as the preliminary ink ejection in order to prevent ejection failure due to thickening or clogging of the reaction liquid nozzle, or to recover ejection failure and ensure ejection stability. It is also necessary to preliminarily discharge the liquid.

  In view of this, for example, Patent Document 1 discloses a method in which a reaction liquid is preliminarily discharged onto a paper surface (hereinafter also referred to as “flushing” or “FL”). Patent Document 2 discloses a method in which a reaction liquid is not preliminarily ejected on a paper surface in order to prevent the flushing dots formed by the ink preliminarily ejected on the paper surface from becoming clear in a printer using the reaction liquid. Is disclosed. Further, Patent Document 3 discloses a method of hiding color dots with white dots by increasing white dots and reducing color dots in order to suppress deterioration in image quality due to preliminary ejection performed on paper. .

JP 2001-301145 A JP 2011-46068 A JP 2010-208217 A

  However, when the reaction liquid is preliminarily ejected onto the recording medium by the method disclosed in the above patent document, the durability of the image is deteriorated, the flocculant contained in the ink or the reaction liquid is precipitated, and the recorded image Problems such as odor caused by the flocculant may occur.

  Also, if both the reaction liquid and ink are preliminarily ejected to a preliminary ejection member such as a flushing box or cloth, the reaction liquid and ink react on the preliminary ejection member, and the solid content of the ink accumulates. Cleaning becomes difficult. For this reason, at the time of preliminary discharge, it is necessary to discharge the reaction liquid and the ink to separate preliminary discharge members.

Furthermore, in a line printer, it may be difficult to perform preliminary discharge to the preliminary discharge member due to the configuration. Therefore, there are methods of pre-ejection so that it is not conspicuous in the blank area where there is no image on the paper surface, or pre-ejection in the recorded image, but because the coagulant of the adhering reaction liquid remains on the recording medium As a result, the image quality may deteriorate. In addition, among nozzles that require preliminary ejection, there are nozzles that do not face the portion where the image of the recording medium exists at all.

  Therefore, some aspects of the present invention improve the image quality and durability of the recorded image obtained while ensuring intermittent ejection stability of the ink and the reaction liquid by solving at least a part of the above-described problems. An ink jet recording apparatus maintenance method and an ink jet recording apparatus are provided.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the maintenance method of the inkjet recording apparatus according to the present invention is as follows.
In an ink jet recording apparatus for recording on a recording medium by discharging a coloring ink composition containing a colorant and a reaction liquid containing a reaction agent that aggregates or thickens the components of the ink composition from an ink jet head,
A maintenance step is provided for performing preliminary discharge in which the droplets of the reaction liquid and the droplets of the clear ink composition containing a resin are discharged from an ink jet head to the recording medium and brought into contact therewith.

  According to the application example, in the maintenance process, the resin contained in the clear ink composition reacts with the reactant in the reaction liquid, so that the reactant reacts with the colored ink composition containing the color material on the surface of the recording medium. The dots are prevented from being sharpened and noticeable. For this reason, it is possible to ensure the intermittent ejection stability of the ink and the reaction liquid while suppressing the occurrence of problems caused by the reactants in the preliminary ejection of the ink and the reaction liquid, and furthermore, the image quality of the obtained recorded image And it becomes possible to improve durability.

[Application Example 2]
In the above application example,
The method may further comprise a step of preliminarily ejecting the colored ink composition onto a preejection member of the ink jet recording apparatus or a step of preliminarily ejecting the coloring ink composition onto the recording medium without contacting the droplets of the reaction liquid.

[Application Example 3]
In the above application example,
It is preferable that the amount of liquid droplets of the reaction liquid brought into contact with the recording medium is smaller than the amount of liquid droplets of the clear ink composition.

[Application Example 4]
In the above application example,
The reactive agent may be at least one selected from the group consisting of a polyvalent metal salt, an organic acid, and a cationic compound.

[Application Example 5]
In the above application example,
The inkjet head may be a line inkjet head or a serial inkjet head.

[Application Example 6]
In the above application example,
The ink jet recording apparatus can perform recording by discharging to the heated recording medium.

[Application Example 7]
In the above application example,
The reaction liquid and the colored ink composition each include a water-soluble organic solvent having a normal boiling point of 250 ° C. or less,
The content of the organic solvent having a normal boiling point of 280 ° C. or higher can be 1% by mass or less.

[Application Example 8]
In the above application example,
The resin may be a resin that reacts with the reactant.

[Application Example 9]
In the above application example,
The inkjet recording apparatus can use the clear ink composition for image formation.

[Application Example 10]
In the above application example,
The recording medium may be a transparent recording medium.

[Application Example 11]
In the above application example,
The pre-recording medium can be a low-absorbing or non-absorbing recording medium.

[Application Example 12]
One aspect of the ink jet recording apparatus according to the present invention is:
Maintenance is performed by the maintenance method of the ink jet recording apparatus according to any one of Application Examples 1 to 11.

1 is a diagram schematically illustrating an example of an ink jet recording apparatus that performs a maintenance method for an ink jet recording apparatus according to an embodiment. FIG.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below demonstrates an example of this invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

  In the inkjet recording apparatus maintenance method according to the present embodiment, a coloring ink composition containing a color material and a reaction liquid containing a reaction agent that aggregates or thickens the components of the ink composition are ejected from an inkjet head for recording. In the ink jet recording apparatus for recording on a medium, a maintenance process for performing preliminary discharge in which the droplet of the reaction liquid and the liquid droplet of the clear ink composition containing resin are discharged from the ink jet head to the recording medium and contacted It is characterized by providing.

Hereinafter, the maintenance method of the inkjet recording apparatus according to the present embodiment will be described in the order of the configuration of the inkjet recording apparatus that performs maintenance by this maintenance method, the reaction liquid, the ink composition (hereinafter also referred to as “ink”), and the recording medium. Then, the process will be described in detail.

1. Each configuration 1.1. Inkjet Recording Apparatus An example of an inkjet recording apparatus in which a maintenance method for an inkjet recording apparatus according to the present embodiment is performed will be described with reference to the drawings. The ink jet recording apparatus that can be used in the maintenance method according to the present embodiment is not limited to the following mode.

  Examples of the ink jet apparatus according to the present embodiment include an ink jet printer (hereinafter, a printer) equipped with the ink jet head shown in FIG. As shown in FIG. 1, the printer 1 is a device that records an image or the like by ejecting liquid ink onto the surface of a recording medium 2 such as recording paper. The printer 1 includes an inkjet head 3, a carriage 4 to which the inkjet head 3 is attached, a carriage moving mechanism 5 that moves the carriage 4 in the main scanning direction (the longitudinal direction of the printer 1, that is, the width direction of the recording medium 2), and recording. A transport mechanism 6 for transporting the medium 2 in the sub-scanning direction (a direction orthogonal to the main scanning direction) is provided.

  Here, the reaction liquid, the clear ink composition, and the colored ink composition used in the ink jet recording apparatus according to the present embodiment are stored in the ink cartridge 7. The ink cartridge 7 is detachably attached to the inkjet head 3. A configuration in which the ink cartridge 7 is disposed on the main body side of the printer 1 and is supplied from the ink cartridge 7 to the inkjet head 3 through an ink supply tube may be employed.

  The carriage moving mechanism 5 includes a timing belt 8. The timing belt 8 is driven by a pulse motor 9 such as a DC motor. Accordingly, when the pulse motor 9 is operated, the carriage 4 is guided by the guide rod 10 installed on the printer 1 and reciprocates in the main scanning direction.

  A platen 11 is arranged below the inkjet head 3 during the recording operation. The platen 11 is arranged at a distance from a nozzle formation surface (nozzle plate; not shown) of the inkjet head 3 when performing a recording operation, and supports the recording medium 2. Further, a flushing box as a preliminary ejection member is disposed at an end portion of the platen 11 in the main scanning direction, specifically, an area outside the area (recording area) where ink is ejected onto the recording medium 2 arranged on the platen 11. 12 is provided. The flushing box 12 is a member that collects the reaction liquid and ink ejected from the inkjet head 3 during preliminary ejection. The flushing box 12 of the present embodiment is formed in a box shape that opens upward (to the inkjet head 3 side). An ink absorbing material (not shown) made of, for example, urethane sponge is disposed on the bottom surface inside the flushing box 12. The flushing boxes 12 are preferably provided on both sides of the platen 11 in the main scanning direction, but may be provided on at least one side.

The ink jet head 3 is means for attaching a reaction liquid or an ink composition to the recording medium 2 and includes a nozzle (not shown) that discharges the reaction liquid or the ink composition. As a method of discharging the reaction liquid or ink composition from the nozzle, for example, a strong electric field is applied between the nozzle and the acceleration electrode placed in front of the nozzle, and the liquid reaction liquid is continuously discharged from the nozzle. A method in which droplets of the reaction liquid are ejected in response to a recording information signal while flying between the deflection electrodes (electrostatic suction method);
Pressure is applied to the reaction liquid with a small pump, and the nozzle is mechanically vibrated with a quartz vibrator, etc., forcing the droplets of the reaction liquid to be discharged; pressure and recorded information signals are output to the reaction liquid with piezoelectric elements At the same time, a method of ejecting and recording reaction liquid droplets (piezo method); a method of thermally foaming a resin liquid with a microelectrode according to a recording information signal, and ejecting and recording reaction liquid droplets (thermal jet method) Etc.

  As the ink-jet head 3, either a line-type ink-jet head or a serial-type ink-jet head can be used, but in this embodiment, a serial-type ink-jet head is used.

  Here, the ink jet recording apparatus provided with the serial ink jet head refers to recording by performing a plurality of scans (passes) for discharging the ink composition while moving the recording head relative to the recording medium. Is to do. In a specific example of the serial type recording head, a recording head is mounted on a carriage that moves in the width direction of the recording medium (a direction that intersects the conveyance direction of the recording medium), and the recording head accompanies the movement of the carriage. In which liquid droplets are ejected onto the recording medium by moving.

  On the other hand, an ink jet recording apparatus equipped with a line type ink jet head performs recording by performing a scan (pass) for discharging the ink composition once while moving the recording head relative to the recording medium. It is. A specific example of the line-type recording head is one in which the recording head is formed wider than the width of the recording medium, and droplets are ejected onto the recording medium without moving the recording head.

  Although not shown, the ink jet apparatus according to the present embodiment may be provided with a drying unit. By providing the drying means, the liquid medium can be quickly evaporated and scattered from the reaction liquid or ink composition attached to the recording medium, and a recorded image or the like can be formed quickly. The drying means that can be employed as the drying means is not particularly limited as long as it has a configuration that promotes evaporation and scattering of the liquid medium contained in the reaction liquid and the ink composition. For example, a means for applying heat to the recording medium, a means for blowing air to the reaction liquid, a means for combining them, and the like can be mentioned. Specifically, forced air heating, radiation heating, conductive heating, high frequency drying, microwave drying, and the like are preferably used.

  Further, the drying by the drying means is preferably drying accompanied by heating, and it is preferable that the ink jet recording apparatus perform recording by discharging to a heated recording medium. The heating method is not particularly limited, and examples thereof include a heat press method, a normal pressure steam method, a high pressure steam method, and a thermofix method. Examples of the heating means for the recording medium include infrared rays (lamps). It is done. In this case, the temperature of the heated recording medium is preferably 30 ° C. or higher and 50 ° C. or lower, and more preferably 30 ° C. or higher and 40 ° C. or lower. In the maintenance process, which will be described later, by preliminarily discharging the heated recording medium, the drying speed of the reaction liquid and the clear ink composition can be increased, and the colored ink composition can be quickly dried in the recording process. Can do.

1.2. Next, the reaction solution will be described. The reaction liquid used in this embodiment contains a reactive agent for aggregating or thickening the ink composition and other components. Hereinafter, components contained in the reaction solution used in the present embodiment and components that can be contained will be described in detail.

<Reactant>
The reaction liquid used in the present embodiment acts on at least one of the colored ink composition and the clear ink composition, preferably the resin contained in the colored ink composition and the clear ink composition, and the components of the ink composition Contains reactants that cause agglomeration or thickening. When the reaction liquid contains the reactive agent, the reactive agent and the resin contained in the ink composition react quickly in a maintenance process and a recording process described later. If it does so, the dispersion state of the colorant and resin in an ink composition will be destroyed, and a colorant and resin will aggregate. In the recording process, the aggregates inhibit the penetration of the colorant into the recording medium, which is considered to be excellent in terms of improving the image quality of the recorded image.

  Further, in the maintenance process, the resin contained in the clear ink composition reacts with the reactant in the reaction liquid, so that the action of the reactant is lost. Thereby, in a recording process, it is prevented that a reactive agent reacts with the coloring ink composition containing a coloring material excessively, and a dot sharpens and stands out. For this reason, it is possible to ensure the intermittent ejection stability of the ink and the reaction liquid while suppressing the occurrence of problems caused by the reactants in the preliminary ejection of the ink and the reaction liquid, and furthermore, the image quality of the obtained recorded image And it becomes possible to improve durability.

  Examples of the reactive agent include polyvalent metal salts, organic acids, and cationic compounds (cationic resins, cationic surfactants, etc.). These reactants may be used alone or in combination of two or more. Among these reactants, it is preferable to use at least one reactant selected from the group consisting of polyvalent metal salts and organic acids from the viewpoint of excellent reactivity with the resin contained in the colored ink composition. .

The polyvalent metal salt is a compound that is composed of divalent or higher polyvalent metal ions and anions that bind to these polyvalent metal ions and is soluble in water. Specific examples of the polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Zn ²⁺ and Ba ²⁺ ; trivalent metal ions such as Al ³⁺ , Fe ³⁺ and Cr ^3+. It is done. Examples of the anion include Cl ⁻ , I ⁻ , Br ⁻ , SO ₄ ²⁻ , ClO ³⁻ , NO ³⁻ , HCOO ⁻ , and CH ₃ COO ⁻ . Among these polyvalent metal salts, calcium salts and magnesium salts are preferable from the viewpoint of the stability of the reaction solution and the reactivity as a reactant.

  Examples of organic acids include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, and tartaric acid. , Lactic acid, sulfonic acid, orthophosphoric acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, or derivatives of these compounds, or salts thereof Etc. are preferable. An organic acid may be used individually by 1 type, and may use 2 or more types together.

  Examples of the cationic resin include a cationic urethane resin, a cationic olefin resin, and a cationic allylamine resin.

  As a cationic urethane resin, a well-known thing can be selected suitably and can be used. As the cationic urethane resin, commercially available products can be used. For example, Hydran CP-7010, CP-7020, CP-7030, CP-7040, CP-7050, CP-7060, CP-7610 (trade name, Dainippon Ink & Chemicals, Inc.), Superflex 600, 610, 620, 630, 640, 650 (trade names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), urethane emulsions WBR-2120C, WBR-2122C (trade names, Taisei) Fine Chemical Co., Ltd.) can be used.

The cationic olefin resin has an olefin such as ethylene or propylene in the structural skeleton, and a known one can be appropriately selected and used. The cationic olefin resin may be in an emulsion state dispersed in a solvent containing water, an organic solvent, or the like. As the cationic olefin resin, commercially available products can be used, and examples thereof include Arrow Base CB-1200, CD-1200 (trade name, manufactured by Unitika Ltd.) and the like.

  As the cationic allylamine resin, known ones can be appropriately selected and used. For example, polyallylamine hydrochloride, polyallylamine amide sulfate, allylamine hydrochloride / diallylamine hydrochloride copolymer, allylamine acetate / diallylamine acetate Copolymer, allylamine acetate / diallylamine acetate copolymer, allylamine hydrochloride / dimethylallylamine hydrochloride copolymer, allylamine / dimethylallylamine copolymer, polydiallylamine hydrochloride, polymethyldiallylamine hydrochloride, polymethyldiallylamine amide sulfate, polymethyldiallylamine acetate , Polydiallyldimethylammonium chloride, diallylamine acetate / sulfur dioxide copolymer, diallylmethylethylammonium ethyl sulfate It can be mentioned sulfur dioxide copolymers, methyl diallyl amine hydrochloride-sulfur dioxide copolymers, diallyldimethylammonium chloride-sulfur dioxide copolymers, diallyldimethylammonium chloride-acrylamide copolymer and the like. As such a cationic allylamine resin, commercially available products can be used. For example, PAA-HCL-01, PAA-HCL-03, PAA-HCL-05, PAA-HCL-3L, PAA-HCL- 10L, PAA-H-HCL, PAA-SA, PAA-01, PAA-03, PAA-05, PAA-08, PAA-15, PAA-15C, PAA-25, PAA-H-10C, PAA-D11- HCL, PAA-D41-HCL, PAA-D19-HCL, PAS-21CL, PAS-M-1L, PAS-M-1, PAS-22SA, PAS-M-1A, PAS-H-1L, PAS-H- 5L, PAS-H-10L, PAS-92, PAS-92A, PAS-J-81L, PAS-J-81 (trade name, Nittobo Medical Association Etsu Chemical Co., Ltd.), Haimo Neo-600, Haimorokku Q-101, Q-311, Q-501, high-Max SC-505, SC-505 (trade name, can be used Haimo Co., Ltd.), and the like.

  Examples of the cationic surfactant include primary, secondary and tertiary amine salt type compounds, alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, Quaternary alkyl ammonium salts, alkyl pyridinium salts, sulfonium salts, phosphonium salts, onium salts, imidazolinium salts and the like can be mentioned. Specific examples of the cationic surfactant include hydrochlorides such as laurylamine, coconutamine and rosinamine, acetates, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, dimethylethyllaurylammonium Ethyl sulfate, dimethyl ethyl octyl ammonium ethyl sulfate, trimethyl lauryl ammonium hydrochloride, cetyl pyridinium chloride, cetyl pyridinium bromide, dihydroxyethyl lauryl amine, decyl dimethyl benzyl ammonium chloride, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl ammonium chloride, hexa Decyldimethylammonium chloride, octadec Dimethyl ammonium chloride.

  The content of the reactant can be appropriately determined so that the above-described effect is exhibited. For example, in 1 kg of the reaction solution, the content of the reactant is preferably 0.1 mol / kg or more and 1.5 mol / kg or less. More preferably, it is 2 mol / kg or more and 1.3 mol / kg or less. The content of the reactant is, for example, preferably 0.5% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 10% by mass or less with respect to the total mass of the reaction solution. Is more preferable.

Confirmation that the reactive agent reacts with the resin contained in the colored ink composition and the clear ink composition can be performed by, for example, whether or not the resin aggregates in a “resin cohesiveness test”. The “resin cohesiveness test” is performed by, for example, visually stirring whether or not a precipitate is generated in the mixed solution while the reactant solution adjusted to the predetermined concentration is dropped into a resin solution containing the resin at a predetermined concentration. Do this by checking.

  Further, as described above, the reactant contained in the reaction liquid acts on at least one of the colored ink composition and the clear ink composition, preferably the resin contained in the colored ink composition and the clear ink composition, Although it has an action of causing aggregation or thickening of the components of the ink composition, the action of the reaction agent is also reduced by covering the reactant attached to the surface of the recording medium with a resin contained in the clear ink composition described later. Therefore, it is not always necessary to have an action of causing aggregation or thickening of the components of the clear ink composition.

<Water>
The reaction solution used in the present embodiment is preferably water as a main solvent. This water is a component that evaporates and scatters by drying after the reaction liquid is attached to the recording medium. The water is preferably water from which ionic impurities such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water are removed as much as possible. In addition, it is preferable to use water sterilized by ultraviolet irradiation or addition of hydrogen peroxide because generation of mold and bacteria can be prevented when the reaction solution is stored for a long time. The content of water contained in the reaction solution can be, for example, 50% by mass or more with respect to the total mass of the reaction solution.

<Organic solvent>
An organic solvent may be added to the reaction solution used in this embodiment. By adding an organic solvent, the wettability of the reaction liquid with respect to the recording medium can be improved. As the organic solvent, the same organic solvents as exemplified in the ink composition described later can be used. Although content of an organic solvent is not specifically limited, For example, it is 1 mass% or more and 40 mass% or less with respect to the total mass of a reaction liquid.

  In addition, it is preferable that a reaction liquid contains the water-soluble organic solvent whose standard boiling point is 250 degrees C or less as an organic solvent, and content of the organic solvent whose standard boiling point is 280 degrees C or more is 1 mass% or less. In this case, since the drying property of the reaction solution is good, drying in the maintenance process is performed quickly, and the sticking of the recorded matter obtained in the recording process is reduced and the abrasion resistance is excellent. In addition, since the drying property is good, the reaction liquid tends to thicken in the nozzle of the ink jet head, and preliminary discharge is essential, so the maintenance process in the present embodiment is effective.

  As the water-soluble organic solvent having a standard boiling point of 250 ° C. or lower, at least one water-soluble organic solvent of alkanediol and alkylene glycol monoether derivative is preferably used. The standard boiling point of the water-soluble organic solvent is preferably 230 ° C. or lower, more preferably 210 ° C. or lower, and further preferably 190 ° C. or lower. Further, the content of the water-soluble organic solvent having a standard boiling point of 250 ° C. or less is more preferably 20% by mass or more, and further preferably 24% by mass or more. Furthermore, the content of the organic solvent having a standard boiling point of 280 ° C. or higher is more preferably 0.8% by mass or less, and further preferably 0.6% by mass or less.

<Surfactant>
A surfactant may be added to the reaction solution used in this embodiment. By adding a surfactant, the surface tension of the reaction solution can be reduced and the wettability with the recording medium can be improved. Among the surfactants, for example, acetylene glycol surfactants, silicon surfactants, and fluorine surfactants can be preferably used. About the specific example of these surfactant, the thing similar to the surfactant illustrated with the below-mentioned coloring ink composition can be used. The content of the surfactant is not particularly limited, but with respect to the total mass of the reaction solution,
It can be 0.1 mass% or more and 1.5 mass% or less.

<Other ingredients>
You may add a pH adjuster, an antiseptic | preservative and antifungal agent, a rust preventive agent, a chelating agent etc. to the reaction liquid used by this embodiment as needed.

1.3. Next, the clear ink composition used in the maintenance process and the recording process will be described. The clear ink composition used in the present embodiment contains a resin and other components, and may be used in a recording process in addition to being used in a maintenance process. Hereinafter, components included in the clear ink composition used in the present embodiment and components that can be included will be described in detail.

<Resin>
The resin contained in the clear ink composition is a resin that reacts with the reactant contained in the reaction liquid described above, and reacts with the reactant in the maintenance process to lose its action. It has functions such as adjusting glossiness (OD) by smoothing the unevenness and improving durability by overcoating the surface of the recorded image. Further, the odor can be reduced by the reaction between the resin and the reactant contained in the clear ink composition. The clear ink composition is not a composition for coloring the recording medium into an image. Therefore, the content of the color material contained in the clear ink composition is preferably 0.3% by mass or less, more preferably 0.1% by mass or less, based on the total mass of the clear ink composition.

  Examples of the resin contained in the clear ink composition include urethane resin, acrylic resin, styrene acrylic resin, fluorene resin, polyolefin resin, rosin modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride. -Well-known resins, such as a vinyl acetate copolymer, ethylene vinyl acetate resin, and ionomer resin, are mentioned. These resins can be used singly or in combination of two or more.

  The resin contained in the clear ink composition preferably includes a resin having a glass transition temperature (Tg) of 0 ° C. or higher, and more preferably includes a resin of 30 ° C. or higher. Although the upper limit of Tg is not specifically limited, Preferably it is 80 degrees C or less, More preferably, it is 60 degrees C or less. By including a resin having a glass transition temperature (Tg) of 0 ° C. or higher, a film can be easily formed, and adhesion to a recording medium is improved. Furthermore, by performing the above heating step at a temperature equal to or higher than the Tg of the resin particles, the resin particles have fluidity, so that a smooth overcoat can be formed on the surface of the recorded image. The glass transition temperature of the resin can be measured by differential scanning calorimetry (DSC method) according to JIS K7121.

  As a form of resin, it is preferable that it is a resin particle at the point which the said effect is easy to be acquired. The average particle size of the resin particles is preferably 200 nm or less, more preferably 10 nm to 150 nm, and particularly preferably 30 nm to 150 nm. When the average particle diameter of the resin particles contained in the clear ink composition is within the above range, the effect of smoothing the unevenness of the surface of the recorded image caused by aggregation or thickening of the resin contained in the colored ink composition is high. Therefore, the gloss (OD) and durability of the recorded image can be further improved. The average particle diameter of the resin particles can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring apparatus include a particle size distribution meter (for example, “Microtrack UPA” manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

The solid content of the resin is preferably 0.5% by mass or more, more preferably from the viewpoint of forming a sufficient overcoat on the surface of the recorded image, with respect to the total mass of the clear ink composition. It is 1% by mass or more, particularly preferably 3% by mass or more. On the other hand, the upper limit value is preferably 17% by mass or less, more preferably 15% by mass or less, still more preferably 13% by mass or less, and particularly preferably 6% by mass in terms of storage stability and ejection stability of the clear ink composition. % Or less.

<Water>
The clear ink composition used in this embodiment preferably uses water as the main solvent. This water is a component that evaporates and scatters by drying after the clear ink composition is attached to the recording area of the recording medium. The water preferably used is the same as that described in the above colored ink composition. The content of water contained in the clear ink composition can be, for example, 50% by mass or more with respect to the total mass of the clear ink composition.

<Organic solvent>
The clear ink composition used in the present embodiment may contain an organic solvent. The organic solvent can give the ink functions such as improving the wettability of the clear ink composition with respect to the recording medium, and preventing the ink-jet head from being dried and improving the ejection stability. About the specific example of an organic solvent, the thing similar to the organic solvent illustrated by description of the above-mentioned coloring ink composition can be used. Although content of an organic solvent is not specifically limited, For example, it is 1 mass% or more and 40 mass% or less with respect to the total mass of a clear ink composition.

  The organic solvent is not particularly limited, and examples thereof include 1,2-alkanediols, polyhydric alcohols (excluding 1,2-alkanediols), pyrrolidone derivatives, glycol ethers, and the like.

  Examples of 1,2-alkanediols include 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, and the like. . 1,2-alkanediols are excellent in the action of increasing the wettability of the clear ink composition to the recording medium to wet it uniformly. When 1,2-alkanediols are contained, the content thereof can be 1% by mass or more and 20% by mass or less with respect to the total mass of the clear ink composition.

  Examples of polyhydric alcohols (excluding 1,2-alkanediols) include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6. -Hexanediol, trimethylolpropane, glycerin and the like. When polyhydric alcohols are contained, the content can be 2% by mass to 30% by mass with respect to the total mass of the clear ink composition.

  Examples of pyrrolidone derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, and 5-methyl-2-pyrrolidone. Etc. The pyrrolidone derivative acts as a good solubilizer for the resin.

Examples of glycol ethers include ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol monoisopropyl ether. Hexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoisoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether , Ethile Glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2 -Ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene glycol Monopropyl ether, dipropylene glycol Propyl ether, and tripropylene glycol monomethyl ether, and the like. These can be used individually by 1 type or in mixture of 2 or more types. Glycol ethers can control the wettability of the clear ink composition to the recording medium.

  In addition, it is preferable that clear ink composition contains the water-soluble organic solvent whose standard boiling point is 250 degrees C or less as an organic solvent, and content of the organic solvent whose standard boiling point is 280 degrees C or more is 1 mass% or less. In this case, since the drying property of the clear ink composition is good, the drying in the maintenance process is quickly performed, the stickiness of the recorded matter obtained in the recording step is reduced, and the obtained image is excellent in abrasion resistance. In addition, the good drying property makes it easy for the clear ink composition to thicken in the nozzles of the ink jet head, making preliminary ejection indispensable, and the maintenance process in this embodiment is effective.

  As the water-soluble organic solvent having a standard boiling point of 250 ° C. or lower, at least one water-soluble organic solvent of alkanediol and alkylene glycol monoether derivative is preferably used. The standard boiling point of the water-soluble organic solvent is preferably 230 ° C. or lower, more preferably 210 ° C. or lower, and further preferably 190 ° C. or lower. Further, the content of the water-soluble organic solvent having a standard boiling point of 250 ° C. or less is more preferably 20% by mass or more, and further preferably 24% by mass or more. Furthermore, the content of the organic solvent having a standard boiling point of 280 ° C. or higher is more preferably 0.8% by mass or less, and further preferably 0.6% by mass or less.

<Surfactant>
The clear ink composition used in the present embodiment may contain a surfactant. The surfactant has functions such as reducing the surface tension of the reaction solution and improving wettability with the recording medium. Among the surfactants, for example, acetylene glycol surfactants, silicon surfactants, and fluorine surfactants can be preferably used. About the specific example of these surfactant, the thing similar to the surfactant illustrated by description of the above-mentioned coloring ink composition can be used. The content of the surfactant is not particularly limited, but can be 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the clear ink composition.

<Other ingredients>
The clear ink composition used in the present embodiment may contain a pH adjuster, an antiseptic / fungicide, a rust inhibitor, a chelating agent, and the like as necessary. In addition, since the film formed by the clear ink composition attaching step is preferably transparent, it usually does not contain a colorant.

1.4. Colored ink composition Next, the colored ink composition used in the recording step described later will be described. The colored ink composition used in the present embodiment contains a resin, a colorant, and other components, and the droplets of the colored ink composition are ejected from the nozzles of the inkjet head to adhere to the recording medium. The image is recorded in the recording area of the recording medium. Thereby, an image made of the colored ink composition is formed in the recording area of the recording medium. Hereinafter, components included in the colored ink composition used in the present embodiment and components that can be included will be described in detail.

<Resin>
The resin contained in the colored ink composition has an action of improving the image quality of the recorded image by reacting with the reactant contained in the reaction liquid. Such a resin reacts with the above-mentioned reactants, the dispersion state of the colorant and the resin in the colored ink composition is destroyed, and the colorant and the resin are aggregated or thickened. Since this aggregate inhibits the penetration of the colorant into the recording medium, landing interference and bleeding of the colored ink composition can be prevented, and lines and fine images can be drawn uniformly. Therefore, it is excellent in terms of improving the image quality of the recorded image. Also, the odor can be reduced by the reaction between the resin and the reactive agent contained in the colored ink composition.

  In order to make such a highly reactive resin, it is not particularly limited, but (1) an anionic resin having an anionic functional group introduced on the surface, or (2) an acid value of 5 mgKOH / g or more. It is preferable to use a resin (preferably 20 mgKOH / g or more, more preferably 40 mg / KOH or more) or (3) a self-dispersing resin that does not depend on an emulsifier. Here, the “anionic resin” refers to a resin having a negative charge as a whole resin. The “self-dispersing resin” refers to a resin that does not require a dispersant and can be dispersed by itself.

  Examples of the resin material include acrylic resin, urethane resin, polyolefin resin, polyester resin, vinyl acetate copolymer resin, and ionomer resin.

  As the form of the resin, resin particles (resin emulsion) or water-soluble resin can be used, but resin particles (resin emulsion) are preferable in view of the above-mentioned effects.

  Among these, the anionic resin emulsion having an anionic functional group on the surface can increase the reactivity (reduce the volume related to the reaction) and can quickly bind to the reactant by electrostatic interaction. preferable. Examples of the anionic functional group include a carboxyl group, a sulfonic acid group, a phosphoric acid group, or a group derived therefrom.

  In the present specification, the “acid value” means the number of mg of KOH required to neutralize 1 g of resin solids, and can be measured by the method described in JIS K0070, for example, a potentiometric titration method. .

  The solid content of the resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, with respect to the total mass of the colored ink composition, in that the lower limit is sufficiently reacted with the reactant. Especially preferably, it is 0.5 mass% or more. On the other hand, the upper limit is preferably 13% by mass or less, more preferably 10% by mass or less, still more preferably 7% by mass or less, and particularly preferably 5% by mass, from the viewpoint of storage stability and ejection stability of the colored ink composition. % Or less.

<Colorant>
The colored ink composition used in the present embodiment contains a colorant. As the colorant, a pigment or an acid dye can be preferably used from the viewpoint that the effect of the present invention is easily obtained.

Among the pigments, examples of the inorganic pigment include carbon black, iron oxide, and titanium oxide. Although it does not specifically limit as said carbon black, For example, furnace black, lamp black, acetylene black, and channel black (CI pigment black 7) are mentioned. Further, as a commercially available product of carbon black, for example, No. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U, Special Black 6, 5, 4A, 4, 250 (all trade names, manufactured by Degussa AG), CONDUCTEX SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700 (all trade names, Columbia Carbon ( Columbian Carbon Japan Ltd), Columbian Chemicals, Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all above) Product name, Cabot Corporation)).

  Organic pigments include, for example, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketo Examples include pyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4 and 60 are listed.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213.

  In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used. These pigments may be used alone or in combination of two or more.

  Examples of the acid dye include acid dyes such as azo, anthraquinone, pyrazolone, phthalocyanine, xanthene, indigoid, and triphenylmethane. Specific examples of the acid dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid black 1, 2, 24, 94 etc. are mentioned. These acidic dyes may be used alone or in combination of two or more.

<Water>
The colored ink composition used in the present embodiment is preferably water as a main solvent. This water is a component that evaporates and disperses by drying after the colored ink composition is attached to the surface of the recording medium. The water is preferably water from which ionic impurities such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water are removed as much as possible. In addition, it is preferable to use water sterilized by ultraviolet irradiation or addition of hydrogen peroxide because generation of mold and bacteria can be prevented when the colored ink composition is stored for a long period of time. The content of water contained in the colored ink composition can be, for example, 50% by mass or more with respect to the total mass of the colored ink composition.

<Organic solvent>
An organic solvent may be added to the colored ink composition used in the present embodiment. By adding an organic solvent, the wettability of the colored ink composition with respect to the recording medium can be improved, the fixability of the recorded image on the recording medium can be improved, and the ejection stability can be improved by preventing drying with the ejection head. This function can be imparted to the ink.

  The organic solvent is not particularly limited, and examples thereof include 1,2-alkanediols, polyhydric alcohols (excluding 1,2-alkanediols), pyrrolidone derivatives, glycol ethers, and the like.

  Examples of 1,2-alkanediols include 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, and the like. . 1,2-alkanediols are excellent in the action of increasing the wettability of the colored ink composition to the recording medium and uniformly wetting it. When 1,2-alkanediols are contained, the content thereof can be 1% by mass or more and 20% by mass or less with respect to the total mass of the colored ink composition.

  Examples of polyhydric alcohols (excluding 1,2-alkanediols) include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6. -Hexanediol, trimethylolpropane, glycerin and the like. When polyhydric alcohols are contained, the content can be 2% by mass or more and 30% by mass or less based on the total mass of the colored ink composition.

  Examples of pyrrolidone derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, and 5-methyl-2-pyrrolidone. Etc. The pyrrolidone derivative acts as a good solubilizer for the resin.

Examples of glycol ethers include ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol monoisopropyl ether. Hexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoisoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether , Ethile Glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2
Ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-methylpentyl ether, diethylene glycol Examples thereof include mono-2-methylpentyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol monomethyl ether. These can be used individually by 1 type or in mixture of 2 or more types. Glycol ethers can control the wettability of the colored ink composition to the recording medium.

  Although content of an organic solvent is not specifically limited, For example, it is 1 mass% or more and 40 mass% or less with respect to the total mass of a coloring ink composition.

  The colored ink composition preferably includes a water-soluble organic solvent having a standard boiling point of 250 ° C. or lower as the organic solvent, and the content of the organic solvent having a standard boiling point of 280 ° C. or higher is preferably 1% by mass or less. In this case, since the drying property of the colored ink composition is good, the stickiness of the recorded matter obtained in the recording step is reduced, and the obtained recorded matter is excellent in abrasion resistance. In addition, due to the good drying property, the colored ink composition tends to thicken in the nozzles of the ink jet head, and preliminary discharge is essential, and the maintenance process in the present embodiment is effective.

  As the water-soluble organic solvent having a standard boiling point of 250 ° C. or lower, at least one water-soluble organic solvent of alkanediol and alkylene glycol monoether derivative is preferably used. The standard boiling point of the water-soluble organic solvent is preferably 230 ° C. or lower, more preferably 210 ° C. or lower, and further preferably 190 ° C. or lower. Further, the content of the water-soluble organic solvent having a standard boiling point of 250 ° C. or less is more preferably 20% by mass or more, and further preferably 24% by mass or more. Furthermore, the content of the organic solvent having a standard boiling point of 280 ° C. or higher is more preferably 0.8% by mass or less, and further preferably 0.6% by mass or less.

<Surfactant>
The colored ink composition according to this embodiment may contain a surfactant. The surfactant has a function of improving the wettability with the recording medium by reducing the surface tension of the ink. Among the surfactants, for example, acetylene glycol surfactants, silicon surfactants, fluorine surfactants and the like can be preferably used.

  Although it does not specifically limit as an acetylene glycol type surfactant, For example, Surfinol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (all are trade names, manufactured by Air Products and Chemicals. Inc.), Olphin B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP. 4001, EXP. 4036, EXP. 4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all trade names, Kawaken Fine Chemical Co., Ltd.).

Although it does not specifically limit as a silicon-type surfactant, A polysiloxane type compound is mentioned preferably. Although it does not specifically limit as the said polysiloxane type compound, For example, polyether modified organosiloxane is mentioned. Commercially available products of the polyether-modified organosiloxane include, for example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (above trade names, manufactured by BYK). KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515 , KF-6011, KF-6012, KF-6015, KF-6017 (above trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

  As the fluorine-based surfactant, a fluorine-modified polymer is preferably used, and specific examples thereof include BYK-340 (manufactured by BYK Japan).

  When the surfactant is contained, the content thereof can be 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the colored ink composition.

<Other ingredients>
The colored ink composition used in the present embodiment may contain a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, a chelating agent, and the like, as necessary.

1.5. Reaction Liquid and Physical Properties of Each Ink Composition The reaction liquid, the colored ink composition, and the clear ink composition (also simply referred to as “ink composition” in the present specification) used in this embodiment are image quality and ink jet recording. From the viewpoint of balance with the reliability of the ink for use, the surface tension at 20 ° C. is preferably 20 mN / m or more and 40 mN / m, and more preferably 20 mN / m or more and 35 mN / m or less. The surface tension is measured by, for example, measuring the surface tension when the platinum plate is wetted with ink in an environment of 20 ° C. using an automatic surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.). It can be measured by checking.

  From the same viewpoint, the viscosity at 20 ° C. of the reaction liquid and the ink composition used in the present embodiment is preferably 3 mPa · s or more and 10 mPa · s or less, and preferably 3 mPa · s or more and 8 mPa · s or less. It is more preferable. The viscosity can be measured, for example, by using a viscoelasticity tester MCR-300 (trade name, manufactured by Pysica) under a 20 ° C. environment.

1.6. Recording Medium In the present embodiment, the recording medium to be printed is not particularly limited, but it is preferable to record on a recording medium with low ink absorption or non-absorption. In a low-absorbing or non-absorbing recording medium, the reaction liquid hardly penetrates into the inside of the recording medium, and the reactant of the reaction liquid attached by the preliminary ejection tends to remain on the surface of the recording medium. There is a risk of image quality degradation. For this reason, the present invention is particularly effective for a low-absorbing or non-absorbing recording medium. However, since a good image quality can be obtained by attaching the colored ink composition or the clear ink composition as soon as possible after the maintenance process, a recording medium with low ink absorption that slightly absorbs ink is more preferable. .

In the present specification, the “ink-absorbing or non-absorbing recording medium” refers to a recording medium having a property of not absorbing or hardly absorbing an ink composition. Quantitatively, a non-ink-absorbing or low-absorbing recording medium is a “recording medium having a water absorption of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method”. Point to. This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method". On the other hand, an ink-absorbing recording medium refers to a recording medium that does not correspond to a non-ink-absorbing or low-absorbing recording medium.

  Examples of non-ink-absorbing recording media include plastic films that do not have an ink absorbing layer, those that are coated with plastic on a substrate such as paper, and those that have a plastic film adhered thereto. . Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

  Examples of the recording medium with low ink absorption include a recording medium provided with a coating layer for receiving ink on the surface. For example, as the base material is paper, art paper, coated paper, mat For example, when the base material is a plastic film, a hydrophilic polymer is applied to the surface of polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc. , Silica and titanium particles are coated with a binder. These recording media may be transparent recording media.

2. Each Step Next, an example of a maintenance method for the ink jet recording apparatus according to the present embodiment will be described.

2.1. Maintenance Step The maintenance step is a step of performing preliminary discharge in which droplets of a reaction liquid and droplets of a clear ink composition containing a resin are discharged from an ink jet head to a recording medium and contacted.

  Here, the preliminary ejection is not ejection of droplets for use in forming an image in the recording process, but is for preventing nozzle thickening and clogging, which is different from the recording process, and for recovering the nozzle. Discharge for maintenance. This preliminary ejection may be performed not only on the recording medium but also on a preliminary ejection member described later, but in this maintenance process, it is performed on the recording medium. The preliminary discharge is also called “flushing (FL)”.

  In the maintenance process of the present embodiment, when the clear ink composition is brought into contact with the reactant that aggregates or thickens the components of the colored ink composition or the clear ink composition contained in the reaction liquid, the clear ink composition includes The resin and the reactant react. Then, the reaction agent is consumed by the reaction of the resin contained in the clear ink with the reaction agent, and the pre-discharge does not remain on the surface of the recording medium, or the reaction agent is covered with the resin contained in the clear ink composition. . For this reason, in the recording process after the maintenance process, when the colored ink composition is attached to the surface of the recording medium, the color dots are prevented from being sharpened and noticeable, and are excellent in terms of improving the image quality of the recorded image. I think it can be done.

  In the present embodiment, the application amount of the reaction liquid and the ink composition can be controlled by using the ink jet method as a method for attaching the reaction liquid to the recording medium.

In the maintenance process, the method of discharging the droplet of the reaction liquid and the droplet of the clear ink composition containing the resin from the nozzle of the inkjet head is based on the inkjet method as described above. Further, the contact between the droplets of the reaction liquid ejected on the recording medium and the liquid droplets of the clear ink composition may cause the reaction liquid and the clear ink composition to be ejected during the same processing and contacted on the recording medium. preferable. Here, “ejection during the same process” means that both droplets of the reaction liquid and the clear ink composition are ejected at a timing at which they can be mixed with each other. For example, in a serial printer, the reaction liquid and the clear ink composition may be landed on the same area in the same scanning.

The maximum adhesion amount of the clear ink composition to the recording medium surface in the maintenance process is preferably 0.5 mg / inch ² or more and 8 mg / inch ² or less, and 2 mg / inch ² or more and 6 mg / inch ² or less. preferable. When the maximum adhesion amount of the clear ink composition to the surface of the recording medium is within the above range, the reactant in the reaction liquid is consumed, and the colored ink composition is adhered to the surface of the recording medium in the recording process after the maintenance process. In this case, it is possible to prevent the color dots from becoming sharp and conspicuous, and to improve the quality of the recorded image.

In addition, the maximum amount of the reaction liquid that adheres to the surface of the recording medium is preferably 0.2 mg / inch ² or more and 3.0 mg / inch ² or less, more preferably 0.5 mg / inch ² or more and 2.0 mg / inch ^2. It is as follows. Since the maximum amount of the reaction liquid adhering to the surface of the recording medium is within the above range, the intermittent ejection stability of the ink and the reaction liquid is suppressed while suppressing the occurrence of problems caused by the reactant in the reaction liquid used in the preliminary ejection. Can be ensured, and further, the image quality and durability of the obtained recorded image can be improved.

  In addition, it is preferable that the liquid amount of the liquid droplet of the reaction liquid brought into contact with the recording medium is smaller than the liquid amount of the liquid droplet of the clear ink composition. The liquid volume of the reaction liquid contacted with the recording medium is smaller than the liquid volume of the clear ink composition liquid droplet, which prevents the occurrence of problems caused by the reactants in the reaction liquid used for preliminary ejection. However, it is possible to ensure the intermittent ejection stability of the ink and the reaction liquid, and it is possible to improve the image quality and durability of the recorded image obtained.

  Further, the maintenance step may include a step of preliminarily discharging the colored ink composition to the above-described predischarge member, or a step of preliminarily discharging the recording medium without contacting the droplets of the reaction liquid. In this case, it is possible to ensure the intermittent ejection stability of the ink and the reaction liquid while suppressing the occurrence of problems due to the reactants in the preliminary ejection of the ink and the reaction liquid, and to obtain a recorded image. Image quality and durability can be improved.

2.2. Processes other than the maintenance process <Surface modification process>
Before the maintenance process, a surface modification process for modifying the surface of the recording medium may be performed in order to improve the wettability of the recording medium to the reaction liquid. For example, by performing surface modification so that the wetting tension index on the surface of a low-absorbing or non-absorbing recording medium is 40 mN / m or more, wetting and spreading properties of the reaction liquid can be improved, and the reaction liquid is recorded on the recording medium. It can be deposited uniformly on the top. Here, the “wetting tension index” is a wetting tension measured according to the “plastic-film and sheet-wetting tension test method (JIS K6768: 1999)”.

  Such a surface modification step is not particularly limited, and for example, corona treatment, atmospheric pressure plasma treatment, flame treatment, ultraviolet irradiation treatment, solvent treatment, resin liquid adhesion treatment (for example, primer treatment), etc. Is mentioned. These processing methods can be performed using a known apparatus.

<Drying process>
It is preferable to provide a drying step for drying the reaction liquid and the clear ink composition attached to the surface of the recording medium after the maintenance step. In this case, it is preferable to perform drying to such an extent that no stickiness is felt when the reaction liquid and the clear ink composition adhered to the surface of the recording medium are touched. This drying step may be performed by natural drying, but as described above, drying with heating is preferable. In this case, the temperature of the heated recording medium is preferably 30 ° C. or higher and 50 ° C. or lower, and more preferably 30 ° C. or higher and 40 ° C. or lower. By preliminarily discharging the heated recording medium, the drying speed of the reaction liquid and the clear ink composition can be increased.

<Recording process>
In the recording process, after the maintenance process described above, a coloring ink composition containing a color material and a reaction liquid containing a reactive agent that aggregates or thickens the components of the ink composition are ejected from an inkjet head onto a recording medium. This is a recording process. In the present embodiment, since the above-described maintenance process is performed before the recording process, the color dots due to the reaction between the colored ink composition and the reactant are prevented from being sharpened and noticeable, and the image quality of the recorded image is improved. Excellent in terms.

  Here, the recording step is to record an image by ejecting a droplet of a colored ink composition and a droplet of a reaction liquid containing a reactive agent from the nozzles of an inkjet head, and depositing them on the surface of a recording medium. Is. Thereby, an image made of a colored ink composition is formed on the surface of the recording medium.

  In the present invention, “image” refers to a recording pattern formed from a group of dots, and includes text printing and solid images. Note that a “solid image” means that dots are recorded for all of the pixels that are the minimum recording unit area defined by the recording resolution. Normally, the recording area of the recording medium is covered with ink and the ground of the recording medium is recorded. This means an image pattern that should be an image that cannot be seen.

The maximum adhesion amount of the colored ink composition to the surface of the recording medium is preferably 5 mg / inch ² or more and 15 mg / inch ² or less. When the maximum adhesion amount of the colored ink composition to the surface of the recording medium is within the above range, the relative ratio between the adhesion amount of the reactant contained in the reaction liquid and the adhesion amount of the resin contained in the color ink composition is It is preferable in that the amount is appropriate and the recording speed can be increased.

  In addition, you may provide the drying process which dries the colored ink composition adhering to the recording medium after the recording process. In this case, it is preferable to dry to such an extent that no stickiness is felt when the colored ink composition adhered to the surface of the recording medium is touched. The drying process of the colored ink composition may be performed by natural drying, but is preferably drying accompanied by heating from the same viewpoint as the drying process of the maintenance process described above. Although the heating method of a coloring ink composition is not specifically limited, The method similar to what was mentioned by the above-mentioned heating method is mentioned.

  Further, in the recording step, the clear ink composition may be used for image formation, or after the recording step, it may be ejected onto the image and overcoated. In this case, the resin and the reactive agent contained in the colored ink composition react with each other to improve the image quality of the recorded image, while the resin contained in the colored ink composition is aggregated or increased. It is recognized that unevenness tends to occur on the surface of the recorded image due to the viscosity, and the gloss (OD) and durability of the recorded image tend to be greatly deteriorated. Therefore, for example, if the surface of an image recorded with a colored ink composition is overcoated with a clear ink composition containing a resin, the gloss (OD) and durability of the recorded image can be greatly improved. And a recorded image having excellent image quality and durability can be recorded.

  When the clear ink composition is used for image formation, it is formed by ejecting droplets of the clear ink composition from the nozzles of the inkjet head and attaching the above-mentioned recording medium reaction liquid and / or colored ink composition. By adhering to the surface of the recorded image, the surface is overcoated.

The maximum adhesion amount of the clear ink composition to the recording medium during image formation is preferably 0.5 mg / inch ² or more and 4 mg / inch ² or less. It is preferable that the maximum adhesion amount of the clear ink composition is within the above range because the thickness of the overcoat can be reduced, the level difference on the surface of the recorded image can be eliminated, and the recording speed can be increased.

  In addition, after making a clear ink composition adhere, you may provide the drying process which dries the clear ink composition adhering to a recording medium. In this case, it is preferable to dry to the extent that no stickiness is felt when the clear ink composition adhered to the recording medium is touched. The drying process of the clear ink composition may be performed by natural drying, but may be drying with heating from the same viewpoint as the drying process in the maintenance process. Although the heating method of a clear ink composition is not specifically limited, The method similar to what was mentioned by the heating method of the above-mentioned reaction liquid is mentioned. In this case, the recording speed can be increased by heating so that the temperature of the recording medium is 40 ° C. or higher (preferably 45 ° C. or higher and 80 ° C. or lower).

3. Examples Hereinafter, the embodiments of the present invention will be described more specifically by way of examples. However, the present embodiments are not limited to these examples.

3.1. Preparation of reaction liquid and ink compositions <Preparation of reaction liquid>
Each component was mixed and stirred so as to have a blending ratio shown in Table 1, and then filtered through a 10 μm membrane filter to prepare each reaction solution. The numerical values in Table 1 all indicate mass%, and ion-exchanged water was added so that the total mass of the reaction solution was 100 mass%.

<Preparation of colored ink composition>
Each component was mixed and stirred so as to have the blending ratio shown in Table 1, and then filtered through a 10 μm membrane filter to prepare each colored ink composition. The numerical values in Table 1 all represent mass%, and ion exchange water was added so that the total mass of the colored ink composition was 100 mass%.

<Preparation of clear ink composition>
Each component was mixed and stirred so as to have the blending ratio shown in Table 1 to obtain each clear ink composition. The numerical values in Table 1 all indicate mass%, and ion exchange water was added so that the total mass of the clear ink composition was 100 mass%.

<Reaction liquid and composition and physical properties of each ink composition>
The composition, flushing (FL) location and flushing amount of each reaction solution and ink composition obtained above are shown in Table 1 below.

In addition, the components described in Table 1 other than the compound names are as follows.
<Color material>
・ Cyan pigment (PB15: 3)
<Resin>
・ Styrene acrylic resin (Brand name "Johncrill 67", manufactured by BASF)
・ Cationic resin (trade name “Kachio Master (registered trademark) PDT-2”, manufactured by Yokkaichi Gosei Co., Ltd.)
・ Silicon surfactant (trade name “BYK-348”, manufactured by Big Chemie Japan Co., Ltd.)

3.2. Printing Experiment Transparent PET (trade name “PL Shin”, manufactured by Lintec Corporation) was used as a recording medium, and SurePress L-4033AW (manufactured by Seiko Epson Corporation) was modified and used as a printer. The remodeling point is that an ink cartridge for one ink and a nozzle row are filled with the reaction liquid and the reaction liquid can be discharged. The ink cartridge and nozzle row for the other ink were filled with the color ink composition and the clear ink composition prepared as described above, respectively. The ink jet head is a long head having the width of the recording medium, and this is mounted on the carriage. The nozzle density of the nozzle row corresponding to one ink is 360 dpi. In addition, the printer used in this experiment was set so that recording can be performed by a single pass method or a multipass method.

In the printer set in this way, the platen heater is operated, the recording surface temperature of the recording medium is set to 40 ° C., and the recording medium fixed on the platen is recorded in the recording area by the multi-pass method. A solid pattern of 5 × 5 cm (recording resolution 1440 × 1440 dpi) was arranged in the vertical and horizontal directions and recorded with the color ink composition. Thereafter, the recorded material was heated at 100 ° C. for 1 minute with a heater arranged downstream of the platen.

  Here, the margin part at the end in the main scanning (pass) direction of the recording area of the recording medium is defined as an FL (flushing) area on the paper surface. For each main scan, the FL of all the nozzles of the ink performing the paper surface FL was performed in the FL area on the paper surface. In an example in which two or more kinds of ink are used as the paper surface FL, the ink is brought into contact with the FL region on the paper surface to make the paper surface FL (except for some examples). Ink with the FL location as the FL area will be in contact with each other when there are two or more types in the FL box provided on the side of the platen (position away from the platen) each time the pass is completed. FL was performed. In Comparative Example 6, the paper surface FL was divided into positions where the reaction liquid and the colored ink composition did not contact on the paper surface. The FL box was filled with non-woven fabric as an ink absorbing material. The FL amount is the total ink amount (mg) of 10 drops when 10 drops FL per second per nozzle.

3.3. Evaluation test <Cleaning of FL material>
Recording was performed continuously for 10 hours, and after recording, the FL box was visually inspected and evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: There is no solid deposit of ink on the upper part of the ink absorber filled in the FL box, or even if there is a deposit, it can be removed by rubbing with a spatula.
X: Even if the deposit is rubbed with a spatula, it cannot be removed.

<Odor>
By directly smelling the odor of the recorded matter obtained as described above, sensory evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
○: There is no odor.
Δ: Slight odor is felt.
X: A considerable odor is felt.

<Visibility of FL dots on paper>
The FL dots in the FL area on the paper surface were visually observed. Coloring with dots (in the case of color dots), the reaction solution dots appearing white (whitening), and whether or not precipitates were visible in the FL area were visually confirmed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: Coloring, whitening and precipitates of FL dots are not noticeable.
Δ: Coloring, whitening, and precipitates of FL dots are slightly noticeable.
X: Coloring, whitening and precipitates of FL dots are very conspicuous.

<Stickness on paper>
The recording surfaces of the two recordings obtained as described above were left over for one day, and the presence or absence of sticking of the recording surface was subjected to sensory evaluation based on the following evaluation criteria.
(Evaluation criteria)
○: No sticking even if left for 1 day.
△: When one sheet is lifted after standing for 1 day, two sheets stick together, but peel off within 1 minute.
X: If one sheet is lifted after standing for 1 day, it will not peel off even after 1 minute or more.

<Abrasion resistance>
The recorded matter obtained as described above was evaluated for abrasion resistance using a Gakushin type friction fastness tester (device name “AB-301”, manufactured by Tester Sangyo Co., Ltd.). Specifically, a pattern portion on which an image is recorded and an on-paper FL area adjacent to the pattern portion are printed on a white cotton cloth (JIS L 08).
03) was rubbed 100 reciprocating times with a load of 500 g. And the stain | pollution | contamination of the stain | pollution | contamination of white cotton cloth and the image (coating film) was observed visually, and it evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: The white cotton cloth is not dirty and the image is not peeled off.
Δ: Stain is observed on the white cotton cloth, but the image is not peeled off.
X: Peeling is recognized on the image.

<Discharge characteristics>
When recording a pattern, a carriage stop time of 10 seconds was provided between passes, and FL was not performed during this stop time. Also, the page FL was not performed. After recording for 1 hour, the nozzle ejection test was performed, and the occurrence of non-ejection nozzles in the nozzle array was tested.
A: The number of non-ejection nozzles is 5% or less.
Δ: The number of non-ejection nozzles exceeds 5%.

3.4. Evaluation Results Examples 1 to 8 and Comparative Examples 1 to 6 were performed based on the recording method and the evaluation test. The recording methods and evaluation results of Examples 1 to 8 and Comparative Examples 1 to 6 are summarized in Table 2 below.

  Examples 1 to 8 have higher evaluations than the comparative examples. In particular, in Examples 1 to 7 in which ejection defects are likely to occur unless flushing is performed, the maintenance method according to the present invention is used. It was possible to reduce the problems caused by the flocculant and was effective. In Example 8, since the reaction liquid and the ink composition contain a large amount of glycerin having a standard boiling point of 290 ° C., the ink is less likely to aggregate or thicken, the FL member can be easily cleaned, and the ejection of the nozzle The characteristics were good. However, since it contains a solvent having a high standard boiling point, glycerin remains on the paper surface, the paper surface becomes sticky, and further, the ink is slow to dry, resulting in poor abrasion resistance.

In Comparative Example 1, since there was no maintenance process before the recording process, the visibility of the dots of the image obtained in the recording process deteriorated. Further, in Comparative Example 2 in which the reaction liquid and the clear ink composition did not contact in the maintenance process, the deposits accumulated in the FL member could not be removed even when rubbed with a spatula and could not be cleaned. Further, in Comparative Example 3 in which the reaction liquid and the colored ink composition were flushed at different locations, the result was that the odor derived from the calcium acetate as the reactant was felt, and in Comparative Example 4, crystals of the reactant due to magnesium sulfate precipitated. In Comparative Example 5, the result was that the surface of the paper became sticky due to the calcium nitrate as a reactant. In Comparative Example 6, since the paper surface was flushed at the position where the reaction liquid and the colored ink composition did not contact on the paper surface, as in Comparative Example 3, the odor derived from the calcium acetate of the reactant was felt.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Printer (inkjet recording device), 2 ... Recording medium, 3 ... Inkjet head, 4 ... Carriage, 5 ... Carriage moving mechanism, 6 ... Conveyance mechanism, 7 ... Ink cartridge, 8 ... Timing belt, 9 ... Pulse motor, 10 ... Guide rod, 11 ... Platen, 12 ... Flushing box (preliminary discharge member)

Claims (12)

In an ink jet recording apparatus for recording on a recording medium by discharging a coloring ink composition containing a colorant and a reaction liquid containing a reaction agent that aggregates or thickens the components of the ink composition from an ink jet head,
A maintenance method for an ink jet recording apparatus, comprising: a maintenance step of performing preliminary ejection in which the droplets of the reaction liquid and the clear ink composition containing resin are ejected from an ink jet head and contacted with the recording medium.   The method further comprises: preliminarily ejecting the colored ink composition onto a preliminary ejection member of the inkjet recording apparatus; or preliminarily ejecting the colored ink composition onto the recording medium without contacting the droplets of the reaction liquid. The maintenance method of the inkjet recording device as described in 1 above.   The maintenance method for an ink jet recording apparatus according to claim 1, wherein a liquid amount of the liquid droplet of the reaction liquid brought into contact with the recording medium is smaller than a liquid amount of the liquid droplet of the clear ink composition.   4. The maintenance method for an ink jet recording apparatus according to claim 1, wherein the reactant is at least one selected from the group consisting of a polyvalent metal salt, an organic acid, and a cationic compound. 5. .   The maintenance method of the ink jet recording apparatus according to any one of claims 1 to 4, wherein the ink jet head is a line ink jet head or a serial ink jet head.   The ink jet recording apparatus maintenance method according to any one of claims 1 to 5, wherein the ink jet recording apparatus performs recording by discharging to the heated recording medium. The reaction liquid and the colored ink composition each include a water-soluble organic solvent having a normal boiling point of 250 ° C. or less,
The maintenance method for an ink jet recording apparatus according to any one of claims 1 to 6, wherein the content of the organic solvent having a standard boiling point of 280 ° C or higher is 1% by mass or less.   The ink jet recording apparatus maintenance method according to claim 1, wherein the resin is a resin that reacts with the reactant.   The maintenance method of the ink jet recording apparatus according to any one of claims 1 to 8, wherein the ink jet recording apparatus uses the clear ink composition for image formation.   The maintenance method of the ink jet recording apparatus according to any one of claims 1 to 9, wherein the recording medium is a transparent recording medium.   The maintenance method of the ink jet recording apparatus according to any one of claims 1 to 10, wherein the pre-recording medium is a low-absorbing or non-absorbing recording medium.   An inkjet recording apparatus that performs maintenance using the maintenance method for an inkjet recording apparatus according to any one of claims 1 to 11.

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