JP2012179761A - Processing liquid for ink jet recording, ink set for ink jet recording, ink jet recording method, curl suppressing method, and ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new processing liquid containing a curl suppressing component.SOLUTION: The processing liquid containing polytungstate can suppress both a minus curl (immediate curl) having four corners of the recording material made to float up when a recording material is put on a flat table with a recording surface down immediately after recording, and a plus curl and a minus curl (long-term curl), the plus curl having the four corners of the recording material made to float up when the recording material is put on the flat table with the recording surface up until a predetermined period of time passes from the recording and the minus curl having the four corners of the recording material made to float up when the recording material is put on the flat table with the recording surface down until a predetermined period of time passes from the recording.

Description

  The present invention relates to a treatment liquid for inkjet recording, an ink set for inkjet recording, an inkjet recording method, a curl suppressing method, and an inkjet recording apparatus.

  In ink jet recording using water-based ink, the recorded matter may be curled. As a solution to this problem, a treatment liquid for suppressing curling is known. For example, it has been proposed to include a curl suppressing component in a pretreatment liquid applied to a recording medium before ink ejection (Patent Document 1).

JP 2008-213485 A

  In recent years, the recording operation of an ink jet recording apparatus has been accelerated, and along with this, the importance of curl suppression has increased. For this reason, it is desired that there are various options for the treatment liquid having a curl suppressing function.

  Then, an object of this invention is to provide the novel process liquid containing a curl suppression component.

In order to achieve the above object, the treatment liquid of the present invention is a treatment liquid used for inkjet recording,
It contains polytungstate.

  In view of the above problems, the present inventors have conducted a series of studies, and found that curl suppression effect of recorded matter can be obtained by including polytungstate in the treatment liquid. Moreover, according to the treatment liquid of the present invention, curling of the recorded matter immediately after ink jet recording can be sufficiently suppressed, and curling that occurs after a certain period of time can also be suppressed.

FIG. 1 is a schematic diagram showing an example of the configuration of the ink jet recording apparatus of the present invention. FIG. 2 is a schematic diagram showing another example of the configuration of the ink jet recording apparatus of the present invention.

  In the present invention, “curl” refers to a minus curl in which the four corners of a recorded object rise when the recorded material is placed on a flat table with the recording surface facing down immediately after recording (for example, 1 minute and 5 minutes later). (Hereinafter, sometimes referred to as “curling immediately after”), when the recorded material is placed on a flat table with the recording surface facing upward until a certain period of time (for example, one day or more) has elapsed since recording, Includes a positive curl that rises at the four corners and a minus curl that raises the four corners of the recorded material when the recorded material is placed on a flat table with the recording surface facing down (hereinafter sometimes referred to as "long-term curl"). . According to the treatment liquid of the present invention, it is possible to suppress both the immediate curling and the long-term curling. The treatment liquid of the present invention can also be referred to as a “curl suppression liquid”.

  As described above, the processing liquid of the present invention is a processing liquid used for ink jet recording, and includes polytungstate. The treatment liquid of the present invention may contain other components other than the polytungstate. By including the polytungstate, both the immediate curling and the long-term curling can be suppressed.

  Examples of the polytungstate include lithium polytungstate, sodium polytungstate, and potassium polytungstate. Among these, sodium polytungstate is particularly preferable. A commercially available product may be used as the sodium polytungstate, for example. Examples of the commercially available products include “Sodium polytungstate (Japanese name: sodium polytungstate)” manufactured by Fulka. The polytungstate may be used alone or in combination of two or more.

  The blending amount of the polytungstate is preferably 12% by weight or more based on the total amount of the treatment liquid. By setting the blending amount of the polytungstate to 12% by weight or more, the immediately after curling and the long term curling can be more suitably suppressed. Although the upper limit of the compounding amount of the polytungstate is not particularly limited, it is, for example, 80% by weight or less, and preferably 18% by weight or less. By making the blending amount of the polytungstate 18% by weight or less, plus curl and minus curl after 7 days can be more suitably suppressed.

  The treatment liquid may further contain water. The water is preferably ion exchange water or pure water. The blending amount of the water with respect to the total amount of the treatment liquid may be, for example, the remainder of the other components.

  The treatment liquid may further contain a water-soluble organic solvent. A conventionally well-known thing can be used as said water-soluble organic solvent. Examples of the water-soluble organic solvent include polyhydric alcohol, polyhydric alcohol derivative, alcohol, amide, ketone, keto alcohol, ether, nitrogen-containing solvent, sulfur-containing solvent, propylene carbonate, ethylene carbonate, 1,3-dimethyl- Examples include 2-imidazolidinone. Examples of the polyhydric alcohol include glycerin, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, hexylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, trimethylolpropane, 1, Examples include 5-pentanediol and 1,2,6-hexanetriol. Examples of the polyhydric alcohol derivative include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, Diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl Ether, propylene glycol-n-propyl Ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, Examples include tripropylene glycol-n-propyl ether and tripropylene glycol-n-butyl ether. Examples of the alcohol include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, and benzyl alcohol. Examples of the amide include dimethylformamide and dimethylacetamide. Examples of the ketone include acetone. Examples of the keto alcohol include diacetone alcohol. Examples of the ether include tetrahydrofuran and dioxane. Examples of the nitrogen-containing solvent include pyrrolidone, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, triethanolamine, and the like. Examples of the sulfur-containing solvent include thiodiethanol, thiodiglycol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like. The blending amount of the water-soluble organic solvent with respect to the total amount of the treatment liquid is not particularly limited. The water-soluble organic solvent may be used alone or in combination of two or more.

  The treatment liquid may or may not contain a colorant. When the processing liquid contains a colorant, the amount is preferably such that it does not affect the recorded image.

  The treatment liquid may further contain a conventionally known additive as necessary. Examples of the additive include a surfactant, a viscosity modifier, a surface tension modifier, an antioxidant, and an antifungal agent. Examples of the viscosity modifier include polyvinyl alcohol, cellulose, and a water-soluble resin.

  The treatment liquid can be prepared, for example, by uniformly mixing the polytungstate and other additive components as necessary by a conventionally known method.

  The water-based ink for ink-jet recording (hereinafter, simply referred to as “water-based ink” or “ink”) used together with the treatment liquid of the present invention is not particularly limited, and will be described in the following ink set for ink-jet recording, for example. Water-based ink can be used.

  Next, the ink set for ink jet recording of the present invention (hereinafter sometimes simply referred to as “ink set”) will be described. The ink set of the present invention is an ink set for ink jet recording containing a water base ink for ink jet recording and a treatment liquid, wherein the water base ink is a water base ink containing a colorant, water and a water-soluble organic solvent, Is the treatment liquid of the present invention. The ink set of the present invention in which the water-based ink and the treatment liquid of the present invention are combined can suppress both the immediate curl and the long-term curl.

  The colorant may be a pigment or a dye. In addition, a pigment and a dye may be mixed and used as the colorant.

  Examples of the pigment include carbon black, inorganic pigments, and organic pigments. Examples of the carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of the inorganic pigment include titanium oxide, iron oxide inorganic pigment, and carbon black inorganic pigment. Examples of the organic pigment include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments; phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, Examples thereof include polycyclic pigments such as quinophthalone pigments; dye lake pigments such as basic dye type lake pigments and acid dye type lake pigments; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; Also, other pigments can be used as long as they can be dispersed in the aqueous phase. Specific examples of these pigments include C.I. I. Pigment Black 1, 6, and 7; C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 78, 150, 151, 154, 180, 185 and 194; I. Pigment oranges 31 and 43; C.I. I. Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48: 1, 53: 1, 57, 57: 1, 112, 122, 123, 139, 144, 146, 149, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 221, 222, 224 and 238; I. Pigment violet 196; C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 22 and 60; C.I. I. Pigment green 7 and 36, and the like.

  The pigment may be a self-dispersing pigment. In the self-dispersing pigment, for example, at least one of a hydrophilic functional group such as a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group, and a salt thereof is directly or other than the pigment particle. By being introduced through a chemical bond, it can be dispersed in water without using a dispersant. The self-dispersing pigment is treated with a pigment by a method described in, for example, JP-A-8-3498, JP-T 2000-513396, JP-T 2008-524400, JP-T 2009-515007, and the like. Can be used. As the raw material for the self-dispersing pigment, both inorganic pigments and organic pigments can be used. Examples of pigments suitable for performing the treatment include carbon black such as “MA8” and “MA100” manufactured by Mitsubishi Chemical Corporation and “Color Black FW200” manufactured by Degussa. As the self-dispersing pigment, for example, a commercially available product may be used. Examples of the commercially available products include “CAB-O-JET (registered trademark) 200”, “CAB-O-JET (registered trademark) 250C”, “CAB-O-JET (registered trademark)” manufactured by Cabot Specialty Chemicals. Trademark) 260M "," CAB-O-JET (registered trademark) 270Y "," CAB-O-JET (registered trademark) 300 "," CAB-O-JET (registered trademark) 400 "," CAB-O-JET " (Registered trademark) 450C "," CAB-O-JET (registered trademark) 465M "and" CAB-O-JET (registered trademark) 470Y ";" BONJET (registered trademark) BLACK CW- "manufactured by Orient Chemical Industries, Ltd. 2 "and" BONJET (registered trademark) BLACK CW-3 ";" LIOJET (registered trademark) WD BLACK 0 "manufactured by Toyo Ink Manufacturing Co., Ltd. 2C "; and the like.

  The solid content blending amount of the pigment (pigment solid content) with respect to the total amount of the water-based ink is not particularly limited, and can be appropriately determined depending on, for example, a desired optical density or color. The pigment solid content is, for example, 0.1% by weight to 20% by weight, preferably 1% by weight to 10% by weight, and more preferably 2% by weight to 8% by weight.

  The dye is not particularly limited, and examples thereof include direct dyes, acid dyes, basic dyes, and reactive dyes. Specific examples of the dye include C.I. I. Direct black, C.I. I. Direct Blue, C.I. I. Direct Red, C.I. I. Direct yellow, C.I. I. Direct orange, C.I. I. Direct violet, C.I. I. Direct Brown, C.I. I. Direct Green, C.I. I. Acid Black, C.I. I. Acid Blue, C.I. I. Acid Red, C.I. I. Acid Yellow, C.I. I. Acid Orange, C.I. I. Acid Violet, C.I. I. Basic Black, C.I. I. Basic blue, C.I. I. Basic Red, C.I. I. Basic violet and C.I. I. For example, food black. C. above. I. Examples of direct black include C.I. I. Direct black 17, 19, 32, 51, 71, 108, 146, 154, 168 and the like can be mentioned. C. above. I. Examples of direct blue include C.I. I. Direct blue 6, 22, 25, 71, 86, 90, 106, and 199. C. above. I. Examples of direct red include C.I. I. Direct red 1, 4, 17, 28, 83, and 227. C. above. I. Examples of direct yellow include C.I. I. Direct yellow 12, 24, 26, 86, 98, 132, 142, 173 and the like. C. above. I. Examples of direct orange include C.I. I. Direct orange 34, 39, 44, 46 and 60 are listed. C. above. I. Examples of direct violet include C.I. I. And direct violet 47 and 48. C. above. I. Examples of direct brown include C.I. I. Direct brown 109 etc. are mention | raise | lifted. C. above. I. Examples of direct green include C.I. I. Direct green 59 etc. are mention | raise | lifted. C. above. I. Examples of acid black include C.I. I. Acid Black 2, 7, 24, 26, 31, 52, 63, 112, 118 and the like. C. above. I. Examples of acid blue include C.I. I. Acid Blue 9, 22, 40, 59, 93, 102, 104, 117, 120, 167, 229, and 234. C. above. I. As acid red, for example, C.I. I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87, 92, 94, 115, 180, 256, 289, 315 and 317. C. above. I. Examples of acid yellow include C.I. I. Acid Yellow 11, 17, 23, 25, 29, 42, 61, 71 and the like. C. above. I. Examples of acid orange include C.I. I. Acid orange 7 and 19 etc. are mentioned. C. above. I. Examples of acid violet include C.I. I. Acid Violet 49 and the like. C. above. I. Examples of basic black include C.I. I. Basic black 2 etc. are raised. C. above. I. Examples of basic blue include C.I. I. Basic Blue 1, 3, 5, 7, 9, 24, 25, 26, 28, 29, and the like are listed. C. above. I. Examples of basic red include C.I. I. Basic Red 1, 2, 9, 12, 13, 14, and 37 are listed. C. above. I. Examples of basic violet include C.I. I. And basic violet 7, 14, and 27. C. above. I. Examples of food black include C.I. I. Food black 1 and 2 etc. are mentioned.

  The blending amount of the dye with respect to the total amount of the water-based ink is not particularly limited, and is, for example, 0.1% by weight to 20% by weight, and preferably 0.3% by weight to 10% by weight.

  The colorant may be used alone or in combination of two or more.

  The water used in the water-based ink is preferably ion exchange water or pure water. The blending amount (water ratio) of the water with respect to the total amount of the water-based ink is, for example, 10% by weight to 90% by weight, and preferably 40% by weight to 80% by weight. The said water ratio is good also as the remainder of another component, for example.

  Examples of the water-soluble organic solvent used in the water-based ink include a wetting agent that prevents drying of the water-based ink at the nozzle tip of the ink jet head and a penetrating agent that adjusts the drying speed on the recording medium.

  The wetting agent is not particularly limited, and examples thereof include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, dimethylacetamide Amides such as acetone; Ketones such as acetone; Keto alcohols such as diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; Polyhydric alcohols such as polyalkylene glycol, alkylene glycol and glycerin; 2-pyrrolidone; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone and the like. Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol. Examples of the alkylene glycol include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. These wetting agents may be used alone or in combination of two or more. Among these, polyhydric alcohols such as alkylene glycol and glycerin are preferable.

  The blending amount of the wetting agent with respect to the total amount of the water-based ink is, for example, 0% by weight to 95% by weight, preferably 5% by weight to 80% by weight, and more preferably 5% by weight to 50% by weight. is there.

  Examples of the penetrant include glycol ether. Examples of the glycol ether include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n- Hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, Propylene glycol-n-butyl ether , Dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether And tripropylene glycol-n-butyl ether. The said penetrant may be used individually by 1 type, and may use 2 or more types together.

  The blending amount of the penetrant with respect to the total amount of the water-based ink is, for example, 0% by weight to 20% by weight, preferably 0.1% by weight to 15% by weight, and more preferably 0.5% by weight to 10% by weight.

  The water-based ink may further contain a conventionally known additive as required. Examples of the additive include a surfactant, a pH adjuster, a viscosity adjuster, a surface tension adjuster, and an antifungal agent. Examples of the viscosity modifier include polyvinyl alcohol, cellulose, water-soluble resin and the like.

  The water-based ink is obtained by, for example, uniformly mixing a colorant, water, a water-soluble organic solvent, and, if necessary, other additive components by a conventionally known method, and removing insoluble matters with a filter or the like. Can be prepared.

  Next, in the present invention, the ink set for ink jet recording can also be provided as an ink cartridge. For example, the ink cartridge of the present invention has an ink storage portion and a processing liquid storage portion, the water storage ink of the present invention is stored in the ink storage portion, and the processing liquid of the present invention is stored in the processing liquid storage portion. The ink cartridge of the present invention may have a storage portion for aqueous ink other than the aqueous ink of the present invention.

  The ink cartridge of the present invention may be an ink cartridge assembly in which a water-based ink cartridge and a processing liquid cartridge that are separately formed are assembled, and the inside thereof may be formed to form an ink storage section and a processing liquid storage section. May be an integrated ink cartridge partitioned. As the main body of the ink cartridge of the present invention, for example, a conventionally known one can be used.

  Next, the ink jet recording method and the ink jet recording apparatus of the present invention will be described.

  The ink jet recording method of the present invention is an ink jet recording method for recording using an ink set for ink jet recording containing an aqueous ink for ink jet recording and a processing liquid, the step of applying the processing liquid to a recording medium, and the recording medium And a recording step of recording by ejecting the water-based ink by an inkjet method, and using the ink set for inkjet recording of the present invention as the ink set.

  The ink jet recording apparatus of the present invention is an ink jet recording apparatus including an ink set storage unit, a treatment liquid applying unit, and an ink discharge unit. The ink set storage unit stores the ink set for ink jet recording of the present invention. The treatment liquid constituting the ink set is applied to the recording medium by the treatment liquid application unit, and the water-based ink constituting the ink set is ejected to the recording medium by the ink ejection unit. Features.

  The ink jet recording method of the present invention can be performed using, for example, the ink jet recording apparatus of the present invention. The recording includes printing, printing, printing, and the like.

  The ink jet recording apparatus of the present invention may be, for example, an ink jet recording apparatus in which a line type ink jet head is mounted, or may be an ink jet recording apparatus in which a serial type ink jet head is mounted. The line type ink jet recording apparatus uses a line type ink jet head having a recording width equal to or larger than the width of the recording medium, and can collectively perform recording in the width direction of the recording medium with the ink jet head fixed. Inkjet recording apparatus. On the other hand, in the serial type ink jet recording apparatus, recording is performed while the ink jet head itself moves in the width direction of the recording surface of the recording medium. The line type ink jet recording apparatus has a remarkably higher recording speed than the serial type ink jet recording apparatus. The treatment liquid of the present invention is preferably applied to high-speed recording by the line-type ink jet recording apparatus because it can suppress curling immediately after the above.

  The schematic diagram of FIG. 1 shows an example of the configuration of the ink jet recording apparatus of the present invention. The ink jet recording apparatus 101 of this example is equipped with the line type ink jet head, and is an ink jet system for the upper surface of a recording medium (for example, recording paper) P, that is, a recording area formed on the recording surface. The apparatus is configured to apply (discharge) the processing liquid. As illustrated, the ink jet recording apparatus 101 includes one processing liquid cartridge 1 ′, four ink cartridges 1, one processing liquid application unit (processing liquid discharge head) 2 ′, and four ink discharge units. (Inkjet head) 2, a paper feed unit 11, a paper discharge unit 12, a belt transport mechanism 13, and a control device 16 that controls the entire inkjet recording apparatus 101 are included as main components. The paper feeding unit 11 is disposed on one side (left side in FIG. 1) of the belt conveyance mechanism 13. The paper discharge unit 12 is disposed on the other side (the right side in FIG. 1) of the belt conveyance mechanism 13.

  Inside the ink jet recording apparatus 101, a paper transport path for transporting the recording paper P from the paper feed unit 11 to the paper discharge unit 12 via the belt transport mechanism 13 is formed. A direction in which the recording paper P is transported is a paper transport direction X. The paper feeding unit 11 includes a paper stocker 11a and a pickup roller 11c. The paper stocker 11a accommodates the recording paper P in a stacked state therein, and has an opening formed on the upper surface thereof. The paper stocker 11a is arranged in a state of being inclined toward the downstream side in the paper transport direction X (right side in FIG. 1, hereinafter, simply referred to as “downstream side”). A support plate 11b urged by a spring 11d is disposed in the sheet stocker 11a from the bottom surface toward the upper opening. The recording paper P is laminated on the support plate 11b. The pickup roller 11c is driven by a placement motor (not shown) to pick up (take out) the recording paper P stacked in the paper stocker 11a one by one from the top and pick up the recording paper P The recording paper P is sent downstream. A paper detection sensor 59 is disposed immediately downstream of the paper feeding unit 11. The paper detection sensor 59 determines whether or not the sent recording paper P has reached a recording standby position A located immediately upstream (left side in FIG. 1) in the paper transport direction X of the belt transport mechanism 13. And is adjusted so that the downstream end of the recording paper P at the recording standby position A can be detected. The fed recording paper P passes through the recording standby position A and is transported to the belt transport mechanism 13.

  The belt conveyance mechanism 13 includes two belt rollers 6 and 7, a conveyance belt 8, a platen 15, and a conveyance motor (not shown). The conveyor belt 8 is an endless belt that is wound so as to be stretched between the two belt rollers 6 and 7. An outer surface of the conveyor belt 8 is an outer peripheral surface 8a. The platen 15 is disposed at a position facing a processing liquid ejection head 2 ′ and the four inkjet heads 2, which will be described later, in a region surrounded by the conveyor belt 8. The platen 15 supports the transport belt 8 so that the transport belt 8 does not bend downward in a region facing the treatment liquid ejection head 2 ′ and the four inkjet heads 2. A nip roller 4 is disposed at a position facing the belt roller 7. The nip roller 4 presses the recording paper P against the outer peripheral surface 8a when the recording paper P transported to the belt transport mechanism 13 is placed on the outer peripheral surface 8a. When the transport motor rotates the belt roller 6, the transport belt 8 is driven (rotated). Thus, the transport belt 8 transports the pressed recording paper P toward the paper discharge unit 12 while sticking and holding the recording paper P. A peeling mechanism 14 is provided immediately downstream of the conveyor belt 8. The peeling mechanism 14 is configured to peel the recording paper P adhered to the outer peripheral surface 8 a from the outer peripheral surface 8 a and send it to the paper discharge unit 12.

  The treatment liquid cartridge 1 'contains the treatment liquid of the present invention. The four ink cartridges 1 contain one color each of four colors of water-based inks of yellow, magenta, cyan, and black. The treatment liquid cartridge 1 ′ and the four ink cartridges 1 are fixed side by side on the belt conveyance mechanism 13 along the paper conveyance direction X. The treatment liquid cartridge 1 ′ and the four ink cartridges 1 each have a treatment liquid ejection head 2 ′ and an inkjet head 2 at the lower ends thereof. When the recording paper P transported by the transport belt 8 passes immediately below the processing liquid ejection head 2 ′, first, the processing liquid ejection surface 2a ′ is directed toward the recording area of the recording paper P. The treatment liquid of the present invention is discharged from Next, when the recording paper P transported by the transport belt 8 sequentially passes immediately below the four inkjet heads 2, ink droplets are ejected from the ink ejection surface 2 a toward the recording area of the recording paper P. Discharged. Thereby, a desired image can be formed in the recording area of the recording paper P. Since the recording paper P on which the image has been formed is processed with the processing liquid of the present invention, the curl immediately after and the long-term curl are suppressed.

  The schematic diagram of FIG. 2 shows another example of the configuration of the ink jet recording apparatus. In this figure, the same parts as those in FIG. The ink jet recording apparatus 102 of this example is an apparatus configured to apply the treatment liquid of the present invention to the recording area of the recording paper P by applying a stamp. Therefore, the ink jet recording apparatus 102 of this example does not have a treatment liquid applying means (the treatment liquid cartridge 1 ′, the treatment liquid ejection head 2 ′, and the treatment liquid ejection surface 2 a ′ in FIG. 1) by the inkjet method. Except for these, the configuration of the ink jet recording apparatus 102 of this example is the same as the apparatus shown in FIG.

  As shown in the drawing, in the ink jet recording apparatus 102 of this example, the stamp 41 is disposed at the position of the processing liquid cartridge 1 ′, the processing liquid discharge head 2 ′, and the processing liquid discharge surface 2 a ′ in FIG. 1. The stamp 41 includes a stamp part 41a and a processing liquid storage part 41b. The stamp portion 41a is formed of a flexible and highly absorbent substrate. In the case of recording, the stamp portion 41a contacts the recording area of the recording paper P, and applies the processing liquid of the present invention supplied from the processing liquid storage section 41b to the recording area of the recording paper P. Since the recording paper P is processed with the processing liquid of the present invention, the immediately after curling and the long-term curling are suppressed.

  In the apparatus shown in FIGS. 1 and 2, the treatment liquid of the present invention is applied to the recording area of the recording paper P by an ink jet method and stamp coating, but the present invention is not limited to these. The ink jet recording apparatus may be a system in which the treatment liquid of the present invention is applied to the recording area of the recording paper P by a method such as brush coating or roller coating. Moreover, although the apparatus shown in FIG. 1 and FIG. 2 employ | adopts a line type inkjet head, it is not limited to these, The apparatus which employ | adopted serial type inkjet may be sufficient.

  Next, the curl suppressing method of the present invention will be described. The curl suppressing method of the present invention is a curl suppressing method of suppressing curling of a recording medium using an ink set for ink jet recording, and the recording medium using the ink for ink jet recording of the present invention as the ink set for ink jet recording. And a recording step of recording by discharging the water-based ink onto the recording medium by an inkjet method. The curl suppressing method of the present invention is characterized in that the ink-jet recording ink set of the present invention is used and the treatment liquid applying step and the recording step are performed, and other steps and conditions are not limited at all. Regarding the curling suppression method of the present invention, the description of the treatment liquid of the present invention, the ink set for ink jet recording of the present invention, and the ink jet recording method of the present invention can be cited.

  Next, examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples.

(Preparation of treatment solution)
The components of the treatment liquid composition (Table 1) were uniformly mixed to obtain treatment liquids 1 to 8.

(Preparation of water-based ink)
In the aqueous ink composition (Table 2), components other than the pigment aqueous dispersion were uniformly mixed to obtain an ink solvent. Next, the ink solvent was added to the aqueous dispersion of the pigment and mixed uniformly. Thereafter, the obtained mixture was filtered with a cellulose acetate type membrane filter (pore size: 3.00 μm) manufactured by Toyo Roshi Kaisha, Ltd., thereby obtaining aqueous inks A to G for inkjet recording.

[Examples 1 to 11]
As shown in Table 3, the treatment liquids 1 to 8 were used in combination with the water-based inks A to D for inkjet recording, and (a) immediately after curl evaluation, (b) long-term curl evaluation and (c) comprehensive evaluation. The following method was used.

[Comparative Examples 1 to 7]
As shown in Table 4, the ink-jet recording water-based inks A to G were used alone without being combined with the treatment liquid, and (a) immediately after curl evaluation, (b) long-term curl evaluation and (c) comprehensive evaluation were as follows. The method was performed.

(A) Immediately after curl evaluation Using a bar coater (bar coater rod No. 3 manufactured by Yasuda Seiki Seisakusho Co., Ltd.) on plain paper (My Paper No. 21 manufactured by Ricoh Co., Ltd.) A treatment solution was applied. In Comparative Examples 1 to 7, the treatment liquid was not applied. Subsequently, the aqueous inks of Examples and Comparative Examples were applied onto the plain paper using a bar coater (bar coater rod No. 3 manufactured by Yasuda Seiki Seisakusho Co., Ltd.). The plain paper after application of the water-based ink is placed on a flat table with the application surface facing down, and the floating heights of the four corners of the plain paper are measured 1 minute and 5 minutes after application. Immediately after, the curl was evaluated according to the following evaluation criteria. In addition, if the immediate curling is suppressed by the entire surface coating by the bar coater, it can be determined that the immediately following curl can be suppressed also in the ink jet recording.

Immediately after curl evaluation (after 1 minute and after 5 minutes) Evaluation criteria G: The average of the raised height of the four corners was less than 10 mm NG: The average of the raised height of the four corners was 10 mm or more

(B) Long-term curl evaluation Immediately after the curl evaluation, the plain paper is placed on a flat table with the coating surface facing upward, and the floating heights of the four corners of the plain paper one day after application are measured. The curl was evaluated according to the following evaluation criteria. In addition, if long-term curling is suppressed by full-surface application by a bar coater, it can be determined that long-term curling can be suppressed even in ink jet recording.

Long-term curl evaluation (after 1 day) Evaluation criteria G: The average height of the four corners was less than 10 mm NG: The average height of the four corners was 10 mm or more

(C) Comprehensive evaluation About the Example and the comparative example, comprehensive evaluation was performed according to the following evaluation criteria from the result of said (a) and (b).

Comprehensive evaluation Evaluation criteria G: Evaluation results of immediate curl (1 minute and 3 minutes later) and long-term curl (1 day later) were all G. NG: immediate curl (1 minute and 3 minutes later) and long-term curl There was NG in one of the evaluation results (after 1 day)

  Table 3 shows the evaluation results of Examples 1 to 11. Table 4 shows the evaluation results of Comparative Examples 1 to 7.

  As shown in Table 3, in Examples 1 to 11 using the treatment liquid containing sodium polytungstate, the results of the immediate curl evaluation and the long-term curl were good. In Examples 1 to 4 using the treatment liquid in which the blending amount of sodium polytungstate was 12 to 18% by weight, plus curl after 7 days was also suppressed. On the other hand, as shown in Table 4, in Comparative Examples 1 to 7 in which no treatment liquid was used, the results of the immediate curl evaluation and the long-term curl evaluation were bad. In Comparative Examples 5 to 7 using the aqueous ink containing sodium polytungstate, curling could not be suppressed.

  As described above, the treatment liquid of the present invention can sufficiently suppress curling of a recorded matter immediately after ink jet recording, and can also suppress curling that occurs after a certain period of time has elapsed. The use of the treatment liquid of the present invention is not particularly limited, and can be widely applied to various ink jet recordings.

DESCRIPTION OF SYMBOLS 1 Ink cartridge 1 'Processing liquid cartridge 2 Inkjet head 2' Processing liquid discharge head 4 Nip roller 6, 7 Belt roller 8 Conveying belt 11 Paper feeding part 11a Paper stocker 11b Pickup roller 11d Pickup roller 11d Spring 12 Paper discharging part 13 Belt Conveying mechanism 14 Peeling mechanism 15 Platen 16 Control device 41 Stamp 41a Stamp unit 41b Processing liquid storage unit 59 Paper detection sensor 101, 102 Inkjet recording apparatus

Claims (7)

A treatment liquid used for inkjet recording,
A treatment liquid comprising polytungstate. The treatment liquid according to claim 1, wherein the blending amount of the polytungstate is 12% by weight or more based on the total amount of the treatment liquid. The treatment liquid according to claim 2, wherein the blending amount of the polytungstate is 12% by weight to 18% by weight with respect to the total amount of the treatment liquid. An ink set for ink jet recording comprising an aqueous ink for ink jet recording and a treatment liquid,
The water-based ink is a water-based ink containing a colorant, water and a water-soluble organic solvent,
The ink for inkjet recording, wherein the treatment liquid is the treatment liquid according to any one of claims 1 to 3. An ink jet recording method for recording using an ink set for ink jet recording containing an aqueous ink for ink jet recording and a treatment liquid,
Applying the treatment liquid to a recording medium;
A recording step of discharging and recording the water-based ink on the recording medium by an inkjet method,
An ink jet recording method comprising using the ink set for ink jet recording according to claim 4 as the ink set. A curl suppressing method for suppressing curling of a recording medium using an ink set for inkjet recording,
As the ink set for ink jet recording, using the ink for ink jet recording according to claim 4,
Applying the treatment liquid to a recording medium;
A curling suppression method comprising: a recording step of discharging the water-based ink onto the recording medium by an ink jet method. An ink jet recording apparatus including an ink set storage unit, a treatment liquid application unit, and an ink discharge unit,
An ink set for inkjet recording according to claim 4 is accommodated in the ink set accommodating portion,
The treatment liquid constituting the ink set is applied to a recording medium by the treatment liquid application unit,
An ink jet recording apparatus, wherein the water-based ink constituting the ink set is ejected onto the recording medium by the ink ejecting means.

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