JP2018051823A - Recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording method which reduces discharge failure of a nozzle of a head and can obtain an excellent image quality.SOLUTION: A recording method includes: a heating step of heating a reaction liquid containing a flocculant which flocculates a component of an ink composition by a heating mechanism; a reaction liquid adhesion step of causing the reaction liquid heated by the heating step to adhere to a recording medium by a reaction liquid adhesion mechanism; and an ink adhesion step of discharging the ink composition from the nozzle of an inkjet head, and causing the ink composition to adhere to the recording medium.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recording method.

  Inkjet recording methods are known in which fine ink droplets are ejected from the nozzles of a recording head of an inkjet recording apparatus to record an image on a recording medium, and use in the sign printing field and high-speed label printing field is also being studied. Yes. 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, in order to heat the recording medium in order to obtain an excellent image quality, or to fix the ink early, A reaction liquid containing an ink flocculant may be used after being ejected by inkjet. However, when the recording medium is heated, the nozzle surface of the head that discharges the ink or the reaction liquid is dried, and ejection failure may occur due to nozzle clogging.

  Therefore, for example, in Patent Document 1, when recording using water-based ink containing resin particles made of urethane and acrylic resin, a first heating step of 40 ° C. or higher and 60 ° C. or lower and 40 ° C. or higher and 90 ° C. or lower is performed. A recording method in which the recording medium is heated in the second heating step is disclosed. Patent Document 2 discloses a technique that uses a water-based inkjet ink containing a core-shell resin in order to improve printability, dischargeability, and the like.

JP 2011-201230 A JP 2012-201692 A

  However, even with the above technique, improvement in ejection failure of the head nozzle and improvement in image quality are not sufficient.

  Accordingly, some aspects of the present invention provide a recording method that solves at least a part of the above-described problems, thereby reducing defective ejection of the nozzles of the head and obtaining excellent image quality.

  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 recording method according to the present invention is:
A heating step of heating a reaction liquid containing a flocculant for aggregating the components of the ink composition by a heating mechanism;
A reaction liquid attachment step of attaching the reaction liquid heated in the heating step to a recording medium by a reaction liquid adhesion mechanism;
An ink adhering step of ejecting the ink composition from a nozzle of an ink jet head and adhering the ink composition to a recording medium.

  According to the above application example, the reaction liquid is heated and then adhered, thereby accelerating the drying of the reaction liquid on the recording medium, reducing the solvent component of the reaction liquid remaining on the recording medium, and for the remaining solvent component The image quality can be prevented from being deteriorated due to the slow drying of the ink and the image quality can be improved. Further, the wettability of the reaction liquid on the recording medium is improved, and the reaction liquid can be applied uniformly. Thereby, since the ink sufficiently reacts with the reaction liquid, the image quality can be improved without increasing the primary heating temperature. Moreover, since the image quality is improved by the above, the required amount of the reaction solution itself is reduced. Thereby, the application amount of the reaction solution can be reduced, and a decrease in abrasion resistance can be prevented. Furthermore, compared to the case where the recording medium is heated, it is possible to provide a recording method that can suppress the influence of heat on the head that ejects ink and that is less likely to cause ejection failure due to nozzle clogging. .

[Application Example 2]
In the above application example,
The heating step can be performed in a reaction liquid channel between a reaction liquid container that contains the reaction liquid and the reaction liquid adhesion mechanism.

  According to the above application example, the influence of heat on the ink jet head can be suppressed.

[Application Example 3]
In the above application example,
The temperature of the reaction liquid when adhering to the recording medium can be higher than the temperature of the ink composition when adhering to the recording medium.

  According to the application example, when the temperature of the reaction liquid is higher than the temperature of the ink composition, the reactivity between the reaction liquid and the ink is increased, and the image quality is further improved. In addition, by not increasing the temperature of the ink, the influence of heat on the inkjet head can be further suppressed.

[Application Example 4]
In the above application example,
The temperature of the reaction liquid when adhering to the recording medium may be 30 ° C. or higher and 55 ° C. or lower.

  According to the application example, it is possible to improve the image quality while suppressing the influence of heat on the inkjet head.

[Application Example 5]
In the above application example,
The reaction liquid adhesion mechanism is a mechanism that discharges the reaction liquid from a nozzle of the ink jet head by applying pressure to the reaction liquid in the pressure chamber of the ink jet head by a piezo element and adheres the reaction liquid to the recording medium. be able to.

  According to the application example described above, in an inkjet head having a piezo element, it is possible to improve ejection failure of the nozzles of the head and improve image quality.

[Application Example 6]
In the above application example,
The surface temperature of the recording medium when attaching the reaction solution may be 40 ° C. or less.

  According to the above application example, it is possible to further suppress the influence of heat on the inkjet head.

[Application Example 7]
In the above application example,
In the ink composition, the content of an organic solvent having a standard boiling point of 280 ° C. or more may be 3% by mass or less.

  According to the above application example, the image quality can be further improved.

[Application Example 8]
In the above application example,
It can be used for recording on either non-absorbing or low-absorbing recording media.

  According to the above application example, it is possible to improve the image quality even when recording on a non-absorbing or low-absorbing recording medium.

[Application Example 9]
In the above application example,
The reaction liquid adhesion mechanism can be mounted on the carriage by using a recording apparatus including a carriage on which a head including a nozzle for discharging the ink composition is mounted.

  In the above application example, since the reaction liquid is heated and then adhered to the recording medium by the reaction liquid adhesion mechanism, even when the reaction liquid adhesion mechanism is mounted on the carriage, the ejection failure of the nozzle of the inkjet head is improved. Image quality can be improved.

[Application Example 10]
In the above application example,
The flocculant may be at least one selected from the group consisting of a polyvalent metal salt, a cationic compound, and an organic acid.

  According to the above application example, even when the flocculant is at least one selected from the group consisting of a polyvalent metal salt, a cationic compound, and an organic acid, the recording medium is heated by heating the reaction liquid. Therefore, the ejection failure of the nozzles of the ink jet head can be improved.

FIG. 2 is a perspective view of an external appearance of a main part of an ink jet printer used in a recording method according to an embodiment of the invention. FIG. The conceptual diagram of a heating means. The perspective view which shows typically the structure of the inkjet printer used for the recording method which concerns on other embodiment of this invention.

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.

  The recording method according to the present embodiment includes a heating step of heating a reaction liquid containing a flocculant that aggregates the components of the ink composition by a heating mechanism, and a reaction liquid heated by the heating step by a reaction liquid adhesion mechanism. A reaction liquid attaching step for attaching to a recording medium; and an ink attaching step for discharging the ink composition from a nozzle of an ink jet head to adhere to the recording medium.

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

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

  Examples of the ink jet recording apparatus used in the present embodiment include an ink jet printer (hereinafter also simply referred to as “printer”) as shown in FIG.

  FIG. 1 is a main part external perspective view showing a configuration of an ink jet printer 100 according to the present embodiment, and FIG. 2 is a main part cross-sectional view of the printer 100 viewed from the main scanning direction D2. As shown in FIGS. 1 and 2, the ink jet printer 100 is equipped with a first head (reaction liquid adhesion mechanism) 1 that discharges a reaction liquid from a nozzle by an ink jet discharge method, and a reaction liquid cartridge (reaction liquid container). The second carriage 12 is mounted with a first carriage 2 that is detachably mounted, and a second head (inkjet head) 11 that ejects ink from the nozzles by an ink jet type ejection system and is detachably mounted with an ink cartridge 13. And a transport roller 20. The recording paper M as a recording medium is transported in the transport direction D1 (sub-scanning direction D1) along the transport plate 24 by a transport roller 20 driven by a transport motor (not shown). The printer 100 includes a control unit (not shown), and the operation of the entire printer 100 is controlled by the control unit.

  The first carriage 2 is fixed to a timing belt 4 that is rotationally driven by a first carriage motor 5. By rotating the timing belt 4, the first carriage 2 can move in the main scanning direction D 2 intersecting the transport direction D 1 along the guide shaft 6 fixed to the housing (not shown).

  A reaction liquid cartridge (reaction liquid container) 3 filled with a reaction liquid described later is mounted on the first carriage 2. A first head 1 is provided on the surface of the first carriage 2 in the vertical direction D3 in the downward direction of the drawing. The first head 1 is means for adhering a reaction liquid described later to the recording medium, and includes a plurality of nozzles (not shown) arranged in the transport direction D1 on the lower surface in the vertical direction D3. A reaction liquid containing a flocculant for aggregating the components of the composition is discharged.

That is, in the present embodiment, the first head 1 includes a piezo element (not shown), and the nozzle of the first head 1 is provided by applying pressure to the reaction liquid in the pressure chamber of the first head 1 by the piezo element. 2 is a reaction liquid attachment mechanism that discharges the reaction liquid from the recording paper M to attach the reaction liquid to the recording paper M. When the recording paper M is transported in the transport direction D1 and the reaction liquid is ejected from the first head 1 while the first carriage 2 moves in the main scanning direction D2, the reaction liquid adheres to the recording paper M. .
The attachment of the reaction liquid is not limited to the attachment by the ink jet head (first head 1), and may be an attachment mechanism that can attach to a recording medium such as a roller, a spray, a bar coater, and a brush.

  The first head 1 and the reaction liquid cartridge 3 are connected by a flow path pipe 32 (see FIG. 3) which is a reaction liquid flow path, and the reaction liquid stored in the reaction liquid cartridge 3 is in the flow path pipe 32. The reaction liquid is discharged from the nozzle. The flow path shown in FIG. 3 conceptually shows the flow path of the reaction liquid sent from one reaction liquid cartridge 3 to the first head 1. As shown in FIG. 3, the flow path pipe 32 is spirally wound around a rod-shaped heater member 31 (for example, an electric heater) as a heating mechanism for heating the reaction solution, and is entirely heated by the heater member 31. It has become so. In this manner, the reaction solution supplied from the reaction solution cartridge 3 is heated to a predetermined temperature through the flow path pipe 32 wound around the heater member 31 and heated.

  With such a configuration, the reaction liquid filled in the reaction liquid cartridge 3 is not heated, and only the reaction liquid necessary for discharge is heated to a predetermined temperature before being discharged from the first head 1. The structure of the heating mechanism is not limited to this structure as long as the reaction liquid is heated and the heated reaction liquid can be attached to the recording paper M by the first head 1. As another configuration, for example, a heater that is provided in at least one of the first heads 1 and heats the reaction liquid may be used.

  Here, in the present embodiment, the reaction liquid cartridge 3 is a so-called on-carriage type mounted on a carriage, but is not limited thereto. For example, a so-called off-carriage type in which a container filled with a reaction solution is mounted on the housing of the printer 100 and supplied to the head via a supply pipe may be used.

  A second carriage 12 is provided at a downstream position in the transport direction D1. The second carriage 12 is fixed to a timing belt 14 that is rotationally driven by a second carriage motor 15. By the rotational driving of the timing belt 14, the second carriage 12 can move in the main scanning direction D2 intersecting the transport direction D1 along the guide shaft 16 fixed to the casing.

  An ink cartridge 13 filled with an ink composition is mounted on the second carriage 12. The second head 11 shown in FIG. 2 is provided on the surface of the second carriage 12 in the vertical direction D3 in the downward direction of the drawing. A plurality of nozzles (not shown) arranged in the transport direction D1 are formed on the lower surface of the second head 11 in the vertical direction D3, and the ink composition filled in the ink cartridge 13 is discharged from the nozzles. It is ejected onto the recording paper M.

  When the recording paper M is transported in the transport direction D1 and the second carriage 12 moves in the main scanning direction D2 and the ink composition is ejected from the second head 11, the ink composition adheres to the recording paper M, An image is formed.

  As described above, the second head 11 is means for attaching an ink composition, which will be described later, to the recording medium, and includes a nozzle (not shown) that discharges the ink composition. In the present embodiment, the second head 11 also applies pressure to the ink in the pressure chamber of the second head 11 by a piezo element (not shown), thereby ejecting ink from the nozzles of the second head 11 and ink onto the recording medium. To attach. Similarly to the first head 1, the second head 11 may have a heating mechanism.

In the present embodiment, a piezo method using a piezo element is used as a method for ejecting a reaction liquid or ink from a nozzle from a head by an ink jet type discharge method, but other methods include, for example, a nozzle and A strong electric field is applied between the accelerating electrodes placed in front of the nozzle, and droplet-like reaction liquid or ink is continuously ejected from the nozzle, while the reaction liquid or ink droplets fly between the deflection electrodes. A method that discharges in response to the recorded information signal (electrostatic suction method); pressurizes the reaction liquid or ink with a small pump and mechanically vibrates the nozzle with a quartz oscillator, etc. A method for ejecting ink droplets; a method in which reaction liquid or ink is heated and foamed with a microelectrode in accordance with a recording information signal, and a liquid or ink droplet is ejected or recorded (thermal jet method), etc. And the like.

  Further, as the ink jet head, either a line ink jet head or a serial ink jet head can be used, but in this embodiment, a serial 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.

  As shown in FIGS. 1 and 2, the printer 100 supports the jagged roller 21 and the jagged roller 21 at a position downstream of the first head 1 in the transport direction D <b> 1 so as to freely rotate, and the axial direction is the main scanning direction D <b> 2. The rotating shaft 22 is provided. The jagged roller 21 has a plurality of protrusions (not shown) with sharp tips on the entire outer periphery, and is formed so as to reduce the area where the jagged roller 21 and the recording paper M abut. The jagged roller 21 is disposed in the vicinity of the recording paper M, whereby the reaction liquid is ejected from the first head 1 onto the recording paper M, so that the recording paper M is bent and deformed. The protrusions 21 come into contact with the conveyed recording paper M, so that the deformation of the recording paper M is suppressed.

  A heater 23 is provided at a position between the first head 1 and the second head 11 and downstream of the serrated roller 21 in the transport direction D1. The length of the heater 23 in the longitudinal direction is longer than the length of the recording paper M in the main scanning direction D2, and the heater 23 is provided with the longitudinal direction as the main scanning direction D2. The recording paper M is dried by the heat radiated from the heater 23 toward the recording paper M.

  In addition, it is good also as a structure provided with the plate-shaped heat insulation member which heat-insulates the thermal radiation from the heater 23 along the longitudinal direction (main scanning direction D2) between the heater 23 and the 2nd head 11 in the conveyance direction D1. In this case, the heat insulating member blocks heat radiated from the heater 23 and blocks heat generated by convection generated on the heater 23 side of the heat insulating member. Thereby, clogging of the first and second heads 1 and 11 due to the heat of the heater 23 is prevented.

  Outside the printing region on the right side of the drawing in the main scanning direction D2, a moving mechanism (not shown) is provided that can move the first cap 7 in the vertical direction of the vertical direction D3. When the first head 1 is outside the printing area on the right side of the drawing in the main scanning direction D2, the first cap 7 can cover the surface of the first head 1 on which the nozzles are formed by the moving mechanism.

  The printer 100 is provided with a suction pump (not shown), and the first cap 7 is provided with a flexible pipe 8 connected to the suction pump. When the first cap 7 is in a state of covering the surface on which the nozzles of the first head 1 are formed, the nozzles are sucked by the suction pump, and clogging of the nozzles can be suppressed.

  Similarly, a moving mechanism (not shown) capable of moving the second cap 17 in the vertical direction of the vertical direction D3 is provided outside the printing region on the right side of the drawing in the main scanning direction D2. When the second head 11 is outside the printing region on the right side of the drawing in the main scanning direction D2, the second cap 17 can cover the surface of the second head 11 on which the nozzles are formed by the moving mechanism.

  The printer 100 is provided with a suction pump (not shown) different from the above suction pump, and the second cap 17 is provided with a flexible pipe 18 connected to the suction pump. When the second cap 17 covers the surface on which the nozzles of the second head 11 are formed, the nozzles are sucked by the suction pump, and clogging of the nozzles can be suppressed.

  In the above-described printer 100, an ink jet first head (reaction liquid adhesion mechanism) 1 and an ink jet second head (ink jet head) 11 are provided in separate carriages 2 and 12. In the recording method according to the embodiment, the first head 1 and the second head 11 may be mounted on the same carriage.

  FIG. 4 is a perspective view schematically showing a configuration of a printer 200 used in a recording method according to another embodiment of the present invention. In the printer 200, the carriage 210 is equipped with an ink jet head (reaction liquid adhesion mechanism, ink jet head) 220 having nozzles (not shown) for discharging the reaction liquid and ink provided on the lower surface. The reaction liquid and the ink are filled in the cartridges 230a and 230b and mounted on the carriage 210, respectively. The carriage 210 is reciprocated in the width direction of the recording paper M (main scanning direction D2 in FIG. 4) by the carriage moving mechanism 240. The recording paper M is transported in the transport direction D1 in FIG. 4 by rotating the transport roller 250.

  The printer 200 may include a drying unit 260 for drying the recording paper M after recording. As the drying unit, for example, a platen heater, a warm air heater, an IR heater or the like having a heating function is used. A blower or the like that does not have a heating function is used.

  Similarly to the printer 100, in the printer 200, a flow path pipe 32 (see FIG. 3), which is a reaction liquid flow path, is provided between the head 220 and the reaction liquid cartridge (reaction liquid container) 230a filled with the reaction liquid. The reaction liquid that is connected to the liquid and stored in the reaction liquid cartridge 230a is connected to the nozzle by flowing through the flow path pipe 32, and the reaction liquid is discharged from the nozzle. The flow path pipe 32 is spirally wound around a rod-shaped heater member 31 as a heating mechanism for heating the reaction solution, and the entire flow path pipe 32 is heated by the heater member 31.

1.2. Next, the reaction liquid used in the recording process described later will be described. The reaction liquid used in this embodiment contains an aggregating agent that aggregates the components of the ink composition. Hereinafter, components contained in the reaction solution used in the present embodiment and components that can be contained will be described in detail.

1.2.1. Flocculant The reaction liquid used in the present embodiment contains a flocculant that aggregates the components of the ink composition. When the reaction liquid contains the flocculant, the flocculant and the resin contained in the ink composition react quickly in the recording step described later. If it does so, the dispersion state of the color material and resin in an ink composition will be destroyed, and a color material and resin will aggregate. Then, since this aggregate inhibits the penetration of the color material into the recording medium, it is considered that the aggregate is excellent in terms of improving the image quality of the recorded image.

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

  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, Examples include diallylmethylethylammonium ethyl sulfate / sulfur dioxide copolymer, methyldiallylamine hydrochloride / sulfur dioxide copolymer, diallyldimethylammonium chloride / sulfur dioxide copolymer, diallyldimethylammonium chloride / acrylamide copolymer. 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 flocculant may have a solubility in water of 600 g / L or less. In this embodiment, since the inkjet head is maintained using a maintenance liquid described later, the nozzle surface is ejected by the reaction liquid even when the solubility in water is low and the flocculant is likely to precipitate by drying the nozzle surface. Defects can be eliminated. The effect of the present invention can be obtained even when the solubility in water is 500 g / L or less, and the effect of the present invention can be obtained even when the solubility in water is 400 g / L or less, and further 300 g / L or less. can get.

  The concentration of the flocculant in the reaction solution may be 0.03 mol / kg or more in 1 kg of the reaction solution. Moreover, in 1 kg of reaction liquid, 0.1 mol / kg or more and 1.5 mol / kg or less may be sufficient, and 0.2 mol / kg or more and 0.9 mol / kg or less may be sufficient. Further, the content of the flocculant may be, for example, 0.1% by mass or more and 25% by mass or less, or 0.2% by mass or more and 20% by mass or less based on the total mass of the reaction solution. 0.3 mass% or more and 10 mass or less may be sufficient.

The confirmation that the aggregating agent reacts with the resin contained in the ink composition can be performed by, for example, whether or not the resin agglomerates in the “resin aggregability test”. The “resin cohesiveness test” is performed by, for example, visually stirring whether or not a precipitate is generated in the mixed solution by mixing and stirring the coagulant solution adjusted to a predetermined concentration in a resin solution containing the resin at a predetermined concentration. Do this by checking.

1.2.2. Water The reaction liquid 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, 40% by mass or more, preferably 50% by mass or more, and more preferably 55% by mass or more with respect to the total mass of the reaction solution. More preferably, it is 65% by mass or more.

1.2.3. Organic solvent An organic solvent may be added to the reaction solution used in the present 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. The content of the organic solvent is not particularly limited, but may be, for example, 1% by mass or more and 40% by mass or less, and preferably 5% by mass or more and 30% by mass or less, with respect to the total mass of the reaction solution. It is.

  The reaction solution contains, as an organic solvent, a water-soluble organic solvent having a standard boiling point of 280 ° C. or less, and the content of the water-soluble organic solvent having a standard boiling point of more than 280 ° C. is preferably 3% by mass or less. It is more preferably 1% by mass or less, and further preferably 0.5% by mass or less. In this case, since the drying property of the reaction solution is good, the reaction solution is quickly dried, and the recorded material obtained in the recording process is excellent in reduction in stickiness and abrasion resistance.

  As the water-soluble organic solvent having a normal boiling point of 280 ° C. or lower, at least one water-soluble organic solvent of pyrrolidone derivatives, alkanediols and alkylene glycol monoether derivatives is preferably used. The standard boiling point of the water-soluble organic solvent is preferably 250 ° C. or lower, more preferably 230 ° C. or lower, and further preferably 210 ° C. or lower. Further, the content of the water-soluble organic solvent having a standard boiling point of 280 ° C. or less is more preferably 5% by mass or more, further preferably 10% by mass or more, and more preferably 15% by mass or more. preferable.

1.2.4. Surfactant A surfactant may be added to the reaction solution used in the present 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 ink composition can be used. Although content of surfactant is not specifically limited, It can be 0.1 to 1.5 mass% with respect to the total mass of a reaction liquid.

1.2.5. Other Components To the reaction solution used in the present embodiment, a pH adjuster, an antiseptic / fungicide, a rust inhibitor, a chelating agent, and the like may be added as necessary.

1.2.6. Physical Properties of Reaction Solution When the reaction solution used in this embodiment is ejected by an ink jet recording head, the surface tension at 20 ° C. is preferably 20 mN / m or more and 40 mN / m,
It is more preferable that it is mN / m or more and 35 mN / m or less. The surface tension is measured, for example, by using an automatic surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) and the surface tension when the platinum plate is wetted with the reaction solution in an environment of 20 ° C. It can be measured by confirming.

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

1.2.7. Method for Preparing Reaction Solution The reaction solution used in the present embodiment can be produced by dispersing and mixing the above components by an appropriate method. After sufficiently stirring each of the above components, the target reaction solution can be obtained by performing filtration to remove coarse particles and foreign matters that cause clogging.

1.3. Ink Composition Next, an ink composition used in a recording process described later will be described. The ink composition used in the present embodiment contains, for example, a resin component, a water-soluble organic solvent having a boiling point of 280 ° C. or less, a surfactant, and water. Since such an ink composition has excellent ink drying properties, it can be preferably used for printing on a non-ink-absorbing or low-absorbing recording medium. Hereinafter, components contained in the ink composition in the present embodiment will be described.

1.3.1. Colorant The ink composition used in the present embodiment may contain a colorant. Examples of the color material include dyes and pigments, and it is preferable to use a pigment because it has a property of fading less easily to light or gas. Therefore, an image formed on a recording medium such as a plastic using a pigment is excellent in water resistance, gas resistance, light resistance, and the like, and has good storage stability.

  Although it does not restrict | limit especially as a pigment which can be used in this Embodiment, An inorganic pigment and an organic pigment are mentioned. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. On the other hand, organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinofullerone pigments, etc.) Nitro pigments, nitroso pigments, aniline black, and the like can be used.

  Among the specific examples of pigments that can be used in the present embodiment, examples of carbon black include furnace black, lamp black, acetylene black, channel black and the like (CI Pigment Black 7). 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA77, MA100, no. 2200B, etc. (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, etc. (all trade names, manufactured by Degussa), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, etc. (all trade names, manufactured by Columbia Carbon Co., Ltd.), Regar 400R, 330R, 660R, mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12, etc. (all trade names, manufactured by Cabot Corporation).

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 180, 185, 213 and the like.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment violet 19 and the like.

  Examples of pigments used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 16, 22, 60, and the like.

  Examples of the pigment used for the green ink include C.I. I. Pigment green 7, 8, 36, and the like.

  Examples of the pigment used for the orange ink include C.I. I. Pigment orange 43, 51, 66, and the like.

  The content of the colorant contained in the ink composition is preferably 1.5% by mass or more and 10% by mass or less, and preferably 2% by mass or more and 7% by mass or less with respect to the total mass of the ink composition. Is more preferable.

  In order to apply the above pigment to the ink composition, it is necessary that the pigment can be stably dispersed and held in water. As the method, a method of dispersing with a resin dispersant such as a water-soluble resin and / or a water-dispersible resin (hereinafter, the pigment dispersed by this method is referred to as “resin-dispersed pigment”), a water-soluble surfactant. And / or a method of dispersing with a surfactant of a water-dispersible surfactant (hereinafter, a pigment dispersed by this method is referred to as “surfactant-dispersed pigment”), and hydrophilic functional groups are chemically formed on the surface of pigment particles. A method in which the pigment is dispersed and / or dissolved in water without a dispersant such as the above-described resin or surfactant (hereinafter, the pigment dispersed by this method is referred to as “surface-treated pigment”). ) And the like. In the present embodiment, any of the above resin dispersed pigments, surfactant dispersed pigments, and surface-treated pigments can be used as the ink composition, and a plurality of types can be mixed as necessary.

  Examples of the resin dispersant used in the resin dispersion pigment include polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer. Polymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene -Acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-maleic acid Acid ester copolymer, vinyl acetate-crotonic acid copolymer Body, vinyl acetate-acrylic acid copolymer, and salts thereof. Among these, a copolymer of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, and a polymer comprising a monomer having both a hydrophobic functional group and a hydrophilic functional group are particularly preferable. As the form of the copolymer, any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer can be used.

Examples of the salt include bases such as ammonia, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, tri-iso-propanolamine, aminomethylpropanol, and morpholine. And a salt with a functional compound. The addition amount of these basic compounds is not particularly limited as long as it is not less than the neutralization equivalent of the resin dispersant.

  The molecular weight of the resin dispersant is preferably in the range of 1,000 to 100,000 as the weight average molecular weight, and more preferably in the range of 3,000 to 10,000. When the molecular weight is in the above range, stable dispersion of the colorant in water is obtained, and viscosity control when applied to the ink composition is easy.

  Commercially available products can be used as the resin dispersant described above. Specifically, Joncryl 67 (weight average molecular weight: 12,500, acid value: 213), Joncryl 678 (weight average molecular weight: 8,500, acid value: 215), Joncryl 586 (weight average molecular weight: 4,600) , Acid value: 108), joncryl 611 (weight average molecular weight: 8,100, acid value: 53), joncryl 680 (weight average molecular weight: 4,900, acid value: 215), joncryl 682 (weight average molecular weight) : 1,700, acid value: 238), joncryl 683 (weight average molecular weight: 8,000, acid value: 160), joncryl 690 (weight average molecular weight: 16,500, acid value: 240) , Manufactured by BASF Japan Ltd.).

  The surfactant used in the surfactant-dispersed pigment includes alkane sulfonate, α-olefin sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, acylmethyl taurate, and dialkyl sulfo oxalate. Anionic surfactants such as alkyl sulfate ester salts, sulfated olefins, polyoxyethylene alkyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, monoglycerite phosphate ester salts, Amphoteric surfactants such as alkyl pyridium salts, alkyl amino acid salts, alkyl dimethyl betaines, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylenes Alkylamide, glycerol alkyl esters, nonionic surfactants such as sorbitan alkyl esters.

  The amount of the resin dispersant or the surfactant added to the pigment is preferably 1 part by mass to 100 parts by mass, more preferably 5 parts by mass to 50 parts by mass with respect to 100 parts by mass of the pigment. By being in this range, the dispersion stability of the pigment in water can be ensured.

As the surface-treated pigment, as the hydrophilic functional _{group, -OM, -COOM, -CO -,} - SO 3 M, -SO 2 NH 3, -RSO 3 M, -PO 3 HM, -PO 3 M 3 , —SO ₃ NHCOR, —NH ₃ , —NR ₃ (wherein M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, R represents an alkyl group having 1 to 12 carbon atoms, a substituent, An optionally substituted phenyl group or an optionally substituted naphthyl group.) And the like. These functional groups are physically and / or chemically introduced by grafting directly to the pigment particle surface and / or via other groups. Examples of the polyvalent group include an alkylene group having 1 to 12 carbon atoms, a phenylene group which may have a substituent, or a naphthylene group which may have a substituent.

In addition, as the surface-treated pigment, -SO ₃ M and / or -RSO ₃ M (M is a counter ion, and hydrogen ion, alkali metal ion, ammonium ion is added to the pigment particle surface by a treatment agent containing sulfur. Or an organic ammonium ion)) that has been surface-treated so as to chemically bond, that is, the pigment does not have an active proton, has no reactivity with sulfonic acid, and the pigment is insoluble or hardly soluble. In the solvent, the pigment is dispersed, and then the surface treatment is performed so that —SO ₃ M and / or —RSO ₃ M are chemically bonded to the particle surface by amidosulfuric acid or a complex of sulfur trioxide and tertiary amine. In addition, it is preferably one that can be dispersed and / or dissolved in water.

  Various known surface treatment means can be applied as the surface treatment means for grafting the functional group or a salt thereof directly on the surface of the pigment particles or via a polyvalent group. For example, means for treating a commercially available oxidized carbon black with ozone or a sodium hypochlorite solution to further oxidize the carbon black to make the surface more hydrophilic (for example, JP-A-7-258578, JP-A-H10-238707). 8-3498, JP-A-10-120958, JP-A-10-195331, JP-A-10-237349), means for treating carbon black with 3-amino-N-alkyl-substituted pyridium bromide ( For example, JP-A-10-195360 and JP-A-10-330665), an organic pigment is dispersed in a solvent in which the organic pigment is insoluble or hardly soluble, and a sulfone group is introduced onto the pigment particle surface by a sulfonating agent. Means (for example, JP-A-8-283596, JP-A-10-110110, JP-A-10-1101 No. 1), means for dispersing an organic pigment in a basic solvent that forms a complex with sulfur trioxide, treating the surface of the organic pigment by adding sulfur trioxide, and introducing a sulfone group or a sulfonamino group (For example, Unexamined-Japanese-Patent No. 10-110114) etc. are mentioned, However, The preparation means for the surface treatment pigment used by this invention is not limited to these means.

  The functional group grafted on one pigment particle may be single or plural kinds. The type and degree of the functional group to be grafted may be appropriately determined in consideration of the dispersion stability in the ink, the color density, the drying property on the front surface of the inkjet head, and the like.

  As a method for dispersing the above-described resin dispersed pigment, surfactant dispersed pigment, and surface-treated pigment in water, the pigment-dispersed pigment, water, and resin dispersant for the resin-dispersed pigment, and the pigment, water, and interface for the surfactant-dispersed pigment. For activators and surface-treated pigments, add surface-treated pigment and water, and water-soluble organic solvents / neutralizers, etc., if necessary. Ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid It can be carried out by a conventionally used disperser such as a mill, an ultrasonic homogenizer, a jet mill, or an ang mill. In this case, the dispersion of the pigment in water is ensured by dispersing the pigment until the average particle size is in the range of 20 nm to 500 nm, more preferably in the range of 50 nm to 200 nm. This is preferable.

1.3.2. Resin Component In the present embodiment, the ink composition contains a water-soluble and / or water-insoluble resin component. The resin component has a function of solidifying the ink and further firmly fixing the ink solidified material on the recording medium. The resin component may be in any state dissolved in the ink composition or dispersed in the ink composition. As the resin component in the dissolved state, the above-described resin dispersant used when a pigment is dispersed as the colorant of the ink composition used in the present embodiment can be used. Further, as the resin in a dispersed state, a resin component that is hardly soluble or insoluble in the liquid medium of the ink composition used in the present embodiment is dispersed in the form of fine particles (that is, in an emulsion state or a suspension state). Can be included.

As the resin component, in addition to the resin used as the resin dispersant, polyacrylic acid ester or a copolymer thereof, polymethacrylic acid ester or a copolymer thereof, polyacrylonitrile or a copolymer thereof, polycyanoacrylate , Polyacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene or copolymers thereof, petroleum resin, chroman indene resin, terpene resin, polyvinyl acetate or copolymer thereof, polyvinyl Alcohol, polyvinyl acetal, polyvinyl ether, polyvinyl chloride or a copolymer thereof,
Examples thereof include polyvinylidene chloride, fluororesin, fluororubber, polyvinyl carbazole, polyvinyl pyrrolidone or a copolymer thereof, polyvinyl pyridine, polyvinyl imidazole, polybutadiene or a copolymer thereof, polychloroprene, polyisoprene, and a natural resin. Of these, those having both a hydrophobic part and a hydrophilic part in the molecular structure are particularly preferred.

  In order to obtain the resin component in a fine particle state, the resin component is obtained by the following method, and any of these methods may be used, and a plurality of methods may be combined as necessary. As the method, a polymerization catalyst (polymerization initiator) and a dispersing agent are mixed in a monomer constituting a desired resin component and polymerized (that is, emulsion polymerization), or a resin component having a hydrophilic portion is dissolved in water. This method is obtained by dissolving in water-soluble organic solvent and mixing the solution in water, and then removing the water-soluble organic solvent by distillation, etc., and dissolving the resin component in water-insoluble organic solvent and mixing the solution with the dispersant in the aqueous solution And the like. Said method can be suitably selected according to the kind and characteristic of the resin component to be used. The dispersant that can be used for dispersing the resin component is not particularly limited, but an anionic surfactant (for example, sodium dodecylbenzenesulfonate, sodium lauryl phosphate, polyoxyethylene alkyl ether sulfate ammonium) Salt), nonionic surfactants (for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, etc.). A mixture of seeds or more can be used.

  When the resin component is used in a fine particle state (emulsion form, suspension form), it is possible to use a resin component obtained by a known material / method. For example, those described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, JP-A-4-18462 and the like can be used. Good. Commercially available products can also be used. For example, Microgel E-1002, Microgel E-5002 (trade name, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001, Boncoat 5454 (trade name, Dainippon Ink and Chemicals, Inc.) Co., Ltd.), SAE1014 (trade name, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (trade name, manufactured by Seiden Chemical Co., Ltd.), Jongkrill 7100, Jongkrill 390, Jongkrill 711, Jongkrill 511, Jongkrill 7001, John Crill 632, John Crill 741, John Crill 450, John Crill 840, John Crill 74J, John Crill HRC-1645J, John Crill 734, John Crill 852, John Crill 7600, John Crill 775, John Crill 537J John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790, John Crill 780, John Crill 7610 (trade name, manufactured by BASF Japan Ltd.) and the like.

  When the resin component is used in the form of fine particles, the average particle diameter is preferably in the range of 5 nm to 400 nm, more preferably in the range of 50 nm to 200 nm, from the viewpoint of ensuring the storage stability and ejection stability of the ink composition.

  The glass transition temperature (Tg) of the resin is preferably, for example, from −20 ° C. to 100 ° C., and more preferably from −10 ° C. to 80 ° C.

  The content of the resin component is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 0.5% by mass or more and 10% by mass or less in terms of solid content with respect to the total amount of the ink composition. By being within this range, the ink composition used in the ink jet recording method according to the present embodiment can be solidified and fixed on a plastic medium.

1.3.3. Water-soluble organic solvent In the present embodiment, the ink composition preferably contains a water-soluble organic solvent having a boiling point of 280 ° C. or lower. When the boiling point of the water-soluble organic solvent is 280 ° C. or less, the ink composition ejected onto the recording medium has good drying properties, and an image having excellent abrasion resistance can be obtained.

  Examples of the water-soluble organic solvent having a boiling point of 280 ° C. or lower used in the ink composition include 1,2-alkanediols, polyhydric alcohols, and pyrrolidone derivatives.

  The 1,2-alkanediols are not particularly limited as long as the boiling point is 280 ° C. or lower. For example, 1,2-butanediol (boiling point: 194 ° C.), 1,2-pentanediol (boiling point: 206 ° C.) 1,2-hexanediol (boiling point: 223 ° C.) and the like. Since 1,2-alkanediols are excellent in the action of increasing the wettability of the ink composition to the recording medium and uniformly wetting it, an excellent image can be formed on the recording medium. The content of 1,2-alkanediols is preferably 1% by mass or more and 8% by mass or less with respect to the total mass of the ink composition.

  The polyhydric alcohols are not particularly limited as long as the boiling point is 280 ° C. or lower. For example, ethylene glycol (boiling point: 197 ° C.), diethylene glycol (boiling point: 244 ° C.), propylene glycol (boiling point: 188 ° C.), dipropylene Examples include glycol (boiling point: 232 ° C.), 1,3-propanediol (boiling point: 210 ° C.), 1,4-butanediol (boiling point: 230 ° C.), 1,6-hexanediol (boiling point: 208 ° C.), and the like. . Among these, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and 1,6-hexanediol are preferable from the viewpoint of high vapor pressure and not hindering image drying. Polyhydric alcohols have the effect of preventing clogging or ejection failure by suppressing the drying and solidification of ink on the nozzle surface of the inkjet head, and the vapor pressure is desirable because it is desirable to evaporate and scatter with moisture. Is preferably high. The content of the polyhydric alcohol is preferably 2% by mass or more and 20% by mass or less with respect to the total mass of the ink composition.

  The pyrrolidone derivative is not particularly limited as long as the boiling point is 280 ° C. or lower. For example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl -2-pyrrolidone, 5-methyl-2-pyrrolidone and the like. Pyrrolidone derivatives act as good solubilizers for thermoplastic resins. The content of the pyrrolidone derivative is preferably 3% by mass or more and 25% by mass or less with respect to the total mass of the ink composition.

  An organic solvent having a boiling point exceeding 280 ° C. may delay the drying of the ink and improve the ejection stability of the inkjet head, but on the other hand, it slows the drying of the ink after adhering to the recording medium, and also in the environment. May absorb the water content and reduce image quality and abrasion resistance. For this reason, in this embodiment, the ink composition preferably has an organic solvent content with a standard boiling point of 280 ° C. or higher of 3% by mass or less, more preferably 2% by mass or less, and 1% by mass. More preferably, it is more preferably at most mass%, more preferably at most 0.5 mass%. In this case, the stickiness of the recorded matter obtained in the recording step described later is reduced, and the rub resistance is excellent.

  Examples of the organic solvent having a boiling point exceeding 280 ° C. include glycerin. Since glycerin has high hygroscopicity and high boiling point, it may cause clogging of the head and malfunction. Further, glycerin is preferably not contained in the ink composition because it has poor antiseptic properties and easily propagates mold and fungi.

1.3.4. Surfactant In the present embodiment, the ink composition preferably contains a surfactant. Examples of the surfactant include a silicon-based surfactant and an acetylene glycol-based surfactant.

  As the silicon-based surfactant, a polysiloxane compound or the like is preferably used, and examples thereof include polyether-modified organosiloxane. More specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (above trade names, manufactured by Big Chemie Japan Co., Ltd.), 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.) and the like. Silicon-based surfactants are preferable in that they have a function of spreading uniformly on a plastic medium so as not to cause uneven density or bleeding of ink. The content of the silicon-based surfactant is preferably 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the ink composition.

  Examples of acetylene glycol surfactants include 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 (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.). The acetylene glycol-based surfactant is superior to other surfactants in that it has an excellent ability to maintain surface tension and interfacial tension, and has almost no foaming property. As a result, the ink composition containing the acetylene glycol-based surfactant can maintain the surface tension and the interfacial tension with the member that contacts the ink such as the head nozzle surface properly, and this is applied to the ink jet recording method. In this case, the discharge stability can be improved. In addition, since the ink composition containing an acetylene glycol surfactant exhibits good wettability and penetrability with respect to the recording medium, it is possible to obtain a high-definition image with little density unevenness and bleeding. The content of the acetylene surfactant is preferably 0.1% by mass or more and 1.0% by mass or less with respect to the total mass of the ink composition.

1.3.5. Water In this embodiment, the ink composition contains water. Water is a main medium of the ink composition, and is a component that is evaporated and scattered by drying. 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. Use of water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be suppressed when the pigment dispersion and the ink composition using the pigment dispersion are stored for a long period of time.

1.3.6. Other Ingredients In the present embodiment, the ink composition may further contain a pH adjuster, a polyolefin wax, an antiseptic / antifungal agent, a rust inhibitor, a chelating agent, and the like. When these materials are added, the characteristics of the ink composition can be further improved.

  Examples of the pH adjuster include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, Examples thereof include sodium hydrogen carbonate.

  Examples of polyolefin waxes include waxes produced from olefins such as ethylene, propylene, butylene or derivatives thereof and copolymers thereof, specifically, polyethylene waxes, polypropylene waxes, polybutylene waxes, and the like. As the polyolefin wax, commercially available products can be used. Specifically, Nopcoat PEM17 (trade name, manufactured by San Nopco Co., Ltd.), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals, Inc.), AQUACER 515, AQUACER 593 (The product name, manufactured by Big Chemie Japan Co., Ltd.) can be used.

  The addition of a polyolefin wax is preferable from the viewpoint that the slipperiness of an image formed on a non-ink-absorbing or low-absorbing recording medium with respect to physical contact can be improved, and the abrasion resistance of the image can be improved. The content of the polyolefin wax is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 1% by mass or less, with respect to the total mass of the ink composition. When the content of the polyolefin wax is in the above range, the above-described effects are sufficiently exhibited.

  Examples of antiseptics and fungicides include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one Etc. Examples of commercially available products include Proxel XL2, Proxel GXL (trade name, manufactured by Avicia), Denside CSA, NS-500W (trade name, manufactured by Nagase ChemteX Corporation), and the like.

  Examples of the rust inhibitor include benzotriazole.

  Examples of the chelating agent include ethylenediaminetetraacetic acid and salts thereof (such as ethylenediaminetetraacetic acid dihydrogen disodium salt).

1.3.7. Physical Properties of Ink Composition The ink composition used in the present embodiment has a surface tension at 20 ° C. of 20 mN / m or more and 40 mN / m from the viewpoint of a balance between image quality and reliability as an ink for inkjet recording. It is 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 ink composition used in the present embodiment is preferably 3 mPa · s to 10 mPa · s, and more preferably 3 mPa · s to 8 mPa · s. 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.

1.3.8. Use Since the ink composition used in the present embodiment has ink drying properties, it can be preferably used for printing on a non-ink-absorbing or low-absorbing recording medium.

  As a non-ink-absorbing recording medium, for example, a plastic film coated on a substrate such as a plastic film or paper that has not been surface-treated for inkjet printing (that is, an ink-absorbing layer is not formed). And those having 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 having low ink absorption include printing paper such as art paper, coated paper, and matte paper. In this specification, a non-ink-absorbing or low-absorbing recording medium is also simply referred to as “plastic medium”.

Here, the “ink non-absorbing or low-absorbing recording medium” in this specification means “the water absorption amount from the start of contact to 30 msec ^1/2 in the Bristow method is 10 mL / m ² or less. Recording medium ". 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".

  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. Recording Method The recording method according to the present embodiment includes a heating step of heating a reaction liquid containing an aggregating agent that aggregates the components of the ink composition by a heating mechanism, and a reaction liquid heated by the heating step. A reaction liquid attaching step for attaching to a recording medium by a mechanism; and an ink attaching step for discharging the ink composition from a nozzle of an inkjet head to adhere to the recording medium.

2.1. Heating Step In the present embodiment, the heating step is a step of heating a reaction liquid containing a flocculant that aggregates the components of the ink composition described above by a heating mechanism. In the case of the on-carriage type printer shown in FIGS. 1, 2, and 4, as a method for heating the reaction solution by the heating mechanism, as described above, the flow path pipe 32 spirally wound around the heater member 31. The reaction liquid accommodated in the reaction liquid cartridge 3 is heated by passing through the inside. As other configurations, the heating mechanism may be any mechanism that can heat the reaction liquid and attach the heated reaction liquid to the recording medium by the reaction liquid adhesion mechanism described later. For example, a container for containing the reaction liquid, a path for supplying the reaction liquid from the container to the mechanism with the reaction liquid, and a heater for heating the reaction liquid provided in at least one of the reaction liquid adhesion mechanisms can be used.

  The heating temperature of the reaction liquid is not particularly limited, but is preferably a temperature that does not affect the first head 1 and the second head 11 by heat, and the temperature of the reaction liquid when adhering to the recording paper M is 30 ° C. It is preferable that the temperature be controlled to be 55 ° C. or lower.

2.2. Next, the reaction liquid heated in the heating process is adhered to the recording paper M by the reaction liquid adhesion mechanism. Here, the reaction liquid attaching step is a step different from the above heating mechanism, and it may be attached by an attaching mechanism capable of attaching to a recording medium such as a roller, a spray, an ink jet head, a bar coater, or a brush. . Among these, an attachment mechanism such as an ink jet head or a spray and a recording medium can be attached in a non-contact manner, and an ink jet head is more preferred in terms of easy control of the amount and position of attachment. As described above, the reaction liquid attaching step is a step of attaching the heated reaction liquid to the recording medium by discharging the heated reaction liquid from the nozzles of the ink jet head when the ink jet head described in FIGS. It is.

  Since the reaction liquid adhered to the recording paper M in the reaction liquid adhesion process is heated in the heating process, it is excellent in wetting and spreading property on the recording paper M and can be uniformly applied. For this reason, it reacts sufficiently with the ink deposited in the ink deposition process described later, and an excellent image quality can be obtained. Further, since the reaction liquid is uniformly applied on the recording paper M, the application amount can be reduced. For this reason, it is possible to prevent a reduction in abrasion resistance of the obtained image.

  Here, the temperature of the reaction liquid at the time of attaching the reaction liquid is the temperature of the portion of the reaction liquid adhesion mechanism that contacts the recording medium when the reaction liquid adhesion mechanism is a contact type such as a roller or a bar coater. When the reaction liquid adhesion mechanism is a non-contact type, the temperature is the temperature of the reaction liquid adhesion mechanism at a portion away from the reaction liquid adhesion mechanism so that the reaction liquid adheres to the recording medium. In the case of an inkjet head, it is the temperature of the reaction liquid in a nozzle.

  The temperature of the reaction liquid when adhering to the recording paper M is preferably 30 ° C. or higher and 55 ° C. or lower, more preferably 35 ° C. or higher and 50 ° C. or lower, and further preferably 40 ° C. or higher and 45 ° C. or lower. . When the temperature of the reaction solution is within the above range, the reaction solution can be uniformly applied to the recording paper M, and the image quality can be improved. Further, the influence of heat on the first head 1 and the second head 11 can be suppressed.

  In the case of a non-contact type reaction liquid adhesion mechanism, since the reaction liquid adheres to the recording medium instantly after the reaction liquid leaves the reaction liquid adhesion mechanism, the temperature of the reaction liquid at the time of adhering to the recording medium is It is considered that the temperature is substantially the same as the temperature of the reaction liquid adhesion mechanism at the part where the reaction liquid is separated from the reaction liquid adhesion mechanism.

  Further, the temperature of the reaction liquid when adhering to the recording paper M is higher than the temperature of the ink when adhering the ink to the recording paper M in the ink adhering step described later, and the image quality and ink ejection stability are excellent. Is preferable. As a result, the reaction between the reaction liquid and the ink is further enhanced, and an excellent image quality can be obtained. The temperature of the reaction liquid when adhering to the recording medium is preferably 3 ° C. or higher, more preferably 5 ° C. or higher, more preferably 10 ° C. or higher than the temperature of the ink when adhering to the recording paper medium. . Although not limited, the upper limit is preferably 30 ° C. or less, more preferably 20 ° C. or less. The above temperature is preferable because the image quality and the clogging resistance of the ink and reaction liquid head are particularly excellent.

Further, the surface temperature of the recording paper M when the reaction liquid is adhered is preferably 40 ° C. or less, more preferably 38 ° C. or less, further preferably 35 ° C. or less, and 30 ° C. or less. It is even more preferable that the temperature is 15 ° C. or less, and it is most preferable that the recording paper M is not heated. Since the surface temperature of the recording paper M when the reaction liquid is adhered is low, the influence of heat on not only the first head 1 but also the second head 11 can be suppressed, and clogging of the head can be prevented.

2.3. Ink adhesion process The ink adhesion process is a process in which the ink composition is ejected from the nozzles of the second head 11 and adhered to the recording paper M. By this process, the droplets of the ink composition and the flocculant of the reaction liquid are formed. It reacts on the recording paper M. As a result, an image made of the ink composition is formed on the surface of the recording paper M.

  Here, in this embodiment, “image” indicates 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.

  In the present embodiment, in the ink adhering step, since the reaction liquid is heated and the ink sufficiently reacts with the reaction liquid, the recording paper M is not heated without increasing the primary heating temperature. Although the image quality can be improved, the ink may be heated when it is attached to the recording paper M. By heating the ink in the ink adhering step, the wettability of the ink adhering to the recording paper M is improved, and the image quality is further improved. In this case, the temperature of the ink is preferably 45 ° C. or less, more preferably 35 ° C. or less, and further preferably 25 ° C. or less. The relationship between the temperature of the ink when the ink is ejected and adhered to the recording medium and the temperature of the inkjet head that ejects the ink are the same as the temperature of the reaction liquid when the reaction liquid is adhered to the recording medium by the inkjet head. The same idea is assumed.

  In addition, the surface temperature of the recording paper M when the ink is attached is preferably 40 ° C. or less, more preferably 38 ° C. or less, further preferably 35 ° C. or less, and 30 ° C. or less. Is more preferable, and it is still more preferable that it is 25 degrees C or less. It is also preferable not to heat the recording paper M. Since the surface temperature of the recording paper M when the ink is attached is low, the influence of heat on the second head 11 can be suppressed and clogging of the head can be prevented.

  In addition, you may provide the drying process which dries the reaction liquid and ink adhering to the recording paper M before or after an ink adhesion process. In this case, it is preferable to dry to the extent that no stickiness is felt when the reaction liquid or ink adhered to the surface of the recording paper M is touched. Although a drying process may be performed by natural drying, it is preferable that it is drying accompanying the heating by the heater 23 shown in FIG. 1, for example.

  As described above, in the recording method according to the present embodiment, since the reaction liquid is heated and attached to the recording paper M, drying of the reaction liquid on the recording medium is accelerated, and the solvent component of the reaction liquid remaining on the recording medium. The image quality can be prevented from being deteriorated due to slow drying of the ink due to the remaining solvent component, and the image quality can be improved. Further, the wettability of the reaction liquid on the recording medium is improved, and the reaction liquid can be applied uniformly. Thereby, since the ink sufficiently reacts with the reaction liquid, the image quality can be improved without increasing the primary heating temperature. Moreover, since the image quality is improved by the above, the required amount of the reaction solution itself is reduced. Thereby, the application amount of the reaction solution can be reduced, and a decrease in abrasion resistance can be prevented. Furthermore, compared to the case where the recording medium is heated, it is possible to provide a recording method that can suppress the influence of heat on the head that ejects ink and that is less likely to cause ejection failure due to nozzle clogging. .

Accordingly, for example, in the printer 100 illustrated in FIG. 1, the second head 1 that ejects ink.
1 can be suppressed, and nozzles of the second head 11 that ejects ink can be prevented from being clogged. In addition, as shown in FIG. 4, in the printer 200 in which the reaction liquid adhesion mechanism is mounted on the carriage, when the recording medium paper M is heated, the head 220 that discharges the reaction liquid and ink is affected. In this embodiment, since the reaction liquid is heated and then discharged, the influence of heat on the head 220 that discharges ink can be suppressed, and a recording method in which discharge failure due to nozzle clogging is less likely to occur. Can be provided.

  The reaction liquid does not need to contain a coloring material or a fixing resin compared to ink, and the flocculant is often water-soluble, so the influence of ejection failure due to thickening or solidification when heated is not affected. Not as much as ink. In this way, heating the reaction liquid can reduce the heating of the recording medium, and can improve the ejection failure of the nozzles of the inkjet head. As described above, according to the recording method according to the present embodiment, defective ejection of the nozzles of the inkjet head is reduced, and excellent image quality is obtained.

3. Examples Hereinafter, embodiments of the present invention will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to only these examples.

3.1. Preparation of Ink Composition Each component was mixed and stirred so as to have the blending ratio shown in Table 1 to obtain ink compositions 1 and 2 (hereinafter also referred to as “inks 1 and 2”). The numerical values in Table 1 all indicate mass%, and pure water was added so that the total mass of the ink composition was 100 mass%.

The materials and amounts used are as follows.
<Pigment>
・ PB15: 3 pigment (cyan pigment)
<Solvent>
・ 1,2-Hexanediol ・ Propylene glycol ・ 2-Pyrrolidone ・ Glycerin <Surfactant>
BYK-340: trade name, manufactured by Big Chemie Japan, fluorinated surfactant DF110D: trade name “Surfinol DF110D”, manufactured by Air Products, acetylene glycol surfactant <resin>
・ Styrene acrylic resin (trade name “UF-5022”, manufactured by Toa Gosei Co., Ltd., Tg 75 ° C.)

3.2. Preparation of reaction solutions According to the composition described in Table 2, the components were mixed and stirred, and then filtered through a 10 µm membrane filter to prepare reaction solutions 1 to 3. The numerical values in Table 2 all indicate mass%, and pure water was added so that the total mass of the reaction solution was 100 mass%.

In addition, each component shown in Table 2 is as follows.
<Flocculant>
Magnesium sulfate Cationic polymer (Polyallylamine, trade name “PAA-01”, manufactured by Nittobo Co., Ltd.) Malonic acid <Solvent>
・ 1,2-Hexanediol ・ 2-Pyrrolidone <Surfactant>
BYK-340: trade name, manufactured by BYK Japan, fluorinated surfactant

3.3. Evaluation test 3.3.1. Recording test <Device 1>
As the apparatus 1, an inkjet printer (trade name, manufactured by SC-50650, manufactured by Seiko Epson Corporation) was used. The printer includes a platen heater, and the carriage includes a reaction liquid head and an ink head. An ink head is disposed on the downstream side of the carriage in the recording medium conveyance direction, and a reaction liquid head is disposed on the upstream side. The platen is configured to have a length that opposes the entire recording medium conveyance direction of all heads. As shown in FIG. 4, the recording apparatus includes a nozzle for ejecting ink and a nozzle for ejecting a reaction liquid on the same carriage.

  Using a head having 360 nozzles per nozzle row, the reaction liquid was filled in one row of nozzle rows, and ink was filled in the other row. In the case where the surface temperature of the recording medium is normal temperature or more, the platen heater is operated so that the surface temperature of the recording medium becomes the value in the table. Further, each head is also provided with the heater shown in FIG. 2, and in an example where the discharge temperature is equal to or higher than the normal temperature, the heated reaction liquid or ink is discharged. At that time, the temperature in the vicinity of the nozzle of the nozzle plate was measured and defined as the discharge temperature. The discharge temperature is estimated to be approximately the temperature of the reaction liquid at the nozzle (the temperature of the reaction liquid when adhering to the recording medium). In addition, a secondary heater was installed downstream of the printer head in the transport direction.

<Apparatus 2>
In the apparatus 2, two carriages are provided on the upstream side and the downstream side in the recording medium conveyance direction, and the reaction liquid head is mounted on the upstream carriage and the ink head is mounted on the downstream carriage. Two platens were also provided, one for the upstream reaction liquid head and the other for the downstream ink head. Each platen is provided with a platen heater individually, and the temperature can be controlled independently. Since a heat shield member was installed between the platens so that the temperature did not affect the other platens, it was larger than the apparatus 1. As shown in FIG. 1, the recording apparatus includes a nozzle that ejects ink and a nozzle that ejects a reaction liquid in separate carriages.

<Record>
PET (Lumirror S10, manufactured by Toray Industries, Inc.) was used as a recording medium, and recording was performed with a reaction liquid head and an ink head at a resolution of 720 dpi horizontal and 720 dpi vertical, respectively. The coating amount, ink: 10 mg / inch ^2, the reaction solution: a 2 mg / inch ^2, after forming a pattern reaction recording to the upstream side, and recorded to overlap the ink patterns on the downstream side. The reaction liquid and the ink were continuously attached (first step and second step). Thereafter, the recording medium to which the reaction liquid and the ink adhered was subjected to secondary heating at 80 ° C. for 1 minute by a secondary heater to obtain a recorded matter.

<Image quality evaluation>
By observing the surface of the obtained recorded matter visually and with a magnifying glass, the image quality evaluation of the recorded matter was evaluated according to the following criteria.
(Evaluation criteria)
A: There is no unevenness or bleeding even when observed with a loupe inside and around the recording portion.
B: Although it cannot be seen with eyes, when observed with a magnifying glass, bleeding appears around the recording area.
C: Although it cannot be visually observed, when observed with a magnifying glass, unevenness appears in the recording portion.
D: Unevenness is observed inside the recording portion when visually observed.

3.3.2. Abrasion Resistance The recorded material obtained in the above recording test was allowed to stand in a laboratory at room temperature (25 ° C.) for 1 hour, and then the recorded surface of the recorded material was subjected to Gakushin-type friction fastness tester AB-301 ( By using the product name (manufactured by Tester Sangyo Co., Ltd.) and confirming the peeled state of the recording surface and the state of ink transfer to the cotton cloth when rubbed 18 times with a cotton cloth under a load of 180 g. Sex was evaluated.
(Evaluation criteria)
A: There is no scratch or peeling.
B: There is a scratch or peeling of 1% or less of the stroke area.
C: There are scratches or peeling exceeding 1% of the stroke area.

3.3.3. Head clogging Recording was performed continuously for 2 hours in the same manner as in the recording test. At that time, when half of the nozzles in the nozzle array face the recording medium, ink was not ejected (not used) from the nozzles, and flushing was performed in a flushing box installed beside the platen for each pass. After recording, a non-ejection test of this half nozzle was performed. The test was performed for each head and evaluated according to the following criteria.
(Evaluation criteria)
A: The number of non-ejection nozzles is zero.
B: The number of non-ejection nozzles is 1 to 3.
C: The number of non-ejection nozzles is 4-6.
D: The number of non-ejection nozzles is 7 or more.

3.4. Evaluation results The results of the evaluation tests are shown in the lower part of Table 3.

In the comparative example without the reaction liquid heating step, it was impossible to achieve both good image quality and elimination of ink clogging, but in the example, all evaluations tended to be higher than in the comparative example. It was. When the temperature of the reaction liquid at the time of adhering to the recording medium is high, the reaction liquid is applied uniformly without leaving a residue, so that the reaction liquid and the ink are sufficiently reacted, and there is little occurrence of unevenness or bleeding. . In addition, good image quality was obtained without increasing the ink temperature, and clogging of the head hardly occurred.

  In the example using the apparatus 1, the substrate temperature in the reaction liquid attaching step and the substrate temperature in the ink attaching step are the same. In that case, the clogging property of the ink was deteriorated in Comparative Example 3 in which the substrate temperature was 48 ° C., and the clogging property of Example 4 in which the ink discharge temperature was 45 ° C. was lower than that in Example 1. On the other hand, although the reaction liquid discharge temperature was 45 ° C., the reaction liquid clogging property was not lowered as much as the ink clogging property. In the example using the apparatus 2, it was possible to make the substrate temperature in the reaction liquid adhesion process different from the substrate temperature in the ink adhesion process, but compared with the apparatus 1, the apparatus was complicated and increased in size.

  As described above, in Examples 1 to 9, by having the heating step of heating the reaction liquid by the heating mechanism, a recording method was obtained in which defective ejection of the nozzles of the head was reduced and excellent image quality was obtained.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. 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 ... 1st head (reaction liquid adhesion mechanism), 2 ... 1st carriage, 3, 230a ... Reaction liquid cartridge (reaction liquid container), 11 ... 2nd head (inkjet head), 12 ... 2nd carriage, 13, 230b ... ink cartridge, 31 ... heater member (heating mechanism), 32 ... flow pipe (reaction liquid flow path), 100, 200 ... ink jet printer, 210 ... carriage, 220 ... head (reaction liquid adhesion mechanism, ink jet head), D1 ... transport direction, M ... recording paper (recording medium)

Claims (10)

A heating step of heating a reaction liquid containing a flocculant for aggregating the components of the ink composition by a heating mechanism;
A reaction liquid attachment step of attaching the reaction liquid heated in the heating step to a recording medium by a reaction liquid adhesion mechanism;
An ink adhering step of ejecting the ink composition from a nozzle of an ink jet head and adhering the ink composition to a recording medium.   The recording method according to claim 1, wherein the heating step is performed in a reaction solution flow path from a reaction solution container containing the reaction solution to the reaction solution adhesion mechanism.   The recording method according to claim 1 or 2, wherein a temperature of the reaction liquid when adhering to the recording medium is higher than a temperature of the ink composition when adhering to the recording medium.   The recording method according to any one of claims 1 to 3, wherein a temperature of the reaction liquid when adhering to the recording medium is 30 ° C or higher and 55 ° C or lower.   The reaction liquid adhesion mechanism is a mechanism that discharges the reaction liquid from a nozzle of the ink jet head by applying pressure to the reaction liquid in the pressure chamber of the ink jet head by a piezo element and adheres the reaction liquid to the recording medium. The recording method according to any one of claims 1 to 4.   The recording method according to claim 1, wherein a surface temperature of the recording medium when the reaction liquid is adhered is 40 ° C. or less.   The recording method according to claim 1, wherein the ink composition has a content of an organic solvent having a standard boiling point of 280 ° C. or higher of 3% by mass or less.   The recording method according to claim 1, wherein the recording method is used for recording on a non-absorbent or low-absorbent recording medium.   9. The method according to claim 1, wherein the reaction liquid adhesion mechanism is mounted on the carriage, and is performed using a recording apparatus including a carriage including an inkjet head that discharges the ink composition. The recording method described.   10. The recording method according to claim 1, wherein the flocculant is at least one selected from the group consisting of a polyvalent metal salt, a cationic compound, and an organic acid.

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