JPH10272828A - Ink jet recording method, ink used therefor and anti-curl liquid - Google Patents

Abstract

(57) [Problem] To provide an ink jet recording method, an ink jet recording ink, and an anti-curl liquid which do not curl a recording medium after printing by ink jet. SOLUTION: In the ink jet recording method, after printing on the recording medium using an ink having a wetting time of 30 ms or more and an absorption coefficient of 1.9 ml / m ² · ms ^1/2 or more in the Bristow method. A liquid containing at least water is attached to the back side of the printing surface of the recording medium in an amount equal to or less than the amount of ink required for printing. In the ink jet recording method, the wetting time on the recording medium in the Bristow method is 30 ms or less and the absorption coefficient is 2.
Printing is performed on a recording medium using an ink of 0 ml / m ² · ms ^1/2 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method, and an ink and an anti-curl liquid used therefor.

[0002]

2. Description of the Related Art In recent years, ink jet printers have rapidly spread due to advantages such as low noise and low running cost, and can print not only on paper dedicated to ink jet printers but also on copying paper such as electrophotographic copiers used in general offices. Possible inkjet printers are also on the market. Also, so-called co-papers having both electrophotographic copying machine suitability and ink jet printer suitability have been released from various companies. However, if the amount of ink becomes extremely large due to almost solid printing or the like, such a copy sheet or co-sheet has a problem that curling (paper rounding) occurs during printing by an inkjet printer. In order to improve this point, for example, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 329413 discloses a method of forming a scratch or a hole on the back side of a sheet, but this method has a drawback that the sheet strength is weakened and the sheet is broken by a small amount. Further, Japanese Patent Application Laid-Open No. Hei 7-205543 discloses a method in which the expandable particles in the paper are expanded to bring the density of the paper to a specific range, but there is a drawback that the paper manufacturing method becomes complicated.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such problems and to provide an ink jet recording method, an ink jet recording ink and an anti-curl liquid which do not curl a recording medium after printing by ink jet. To provide.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide an ink-jet recording method in which the wetting time on a recording medium in the Bristow method is 30 ms or more and the absorption coefficient is 1.9 ml / m ² · ms ^1/2 or more. After printing on a recording medium using the ink, the liquid containing at least water is attached to the back side of the printing surface of the recording medium in the same amount or less as the amount of ink required for printing. Achieved by the recording method. The object of the present invention is to
In the ink jet recording method, printing is performed on a recording medium using an ink having a wetting time of 30 ms or less and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. This is achieved by an ink jet recording method.

According to the ink jet recording method of the present invention, the wetting time for the recording medium in the Bristow method is 30 minutes.
After printing on a recording medium using an ink having an absorption coefficient of 1.9 ml / m ² · ms ^1/2 or more, the liquid containing at least water is printed on the back side of the printing surface of the recording medium. By applying the ink in an amount equal to or less than the required amount of ink, it is possible to prevent the recording medium from curling after printing. Furthermore, curl of the recording medium after printing is reduced by using an ink having a wetting time of 50 ms or more and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. Can be better prevented.

Further, as the liquid containing at least water adhered to the back side of the printing surface of the recording medium, it is preferable to use a liquid having a wetting time and an absorption coefficient in the Bristow method similar to the ink used for printing, and particularly a Bristow method. It is preferable to use a liquid having a wetting time to a recording medium of 50 ms or more and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the method. Further, it is particularly preferable to use a liquid composed of components obtained by removing a coloring material from the ink composition used for printing.

In order to cause the liquid containing at least water to adhere to the back side of the printing surface of the recording medium, the amount of application is adjusted by adjusting the distance or the relative speed between the pumping roller and the application roller by, for example, an application roller method. What should I do? In addition, it is not necessary to uniformly apply at least a liquid containing water, but rather an image signal (ink application amount).
It is preferable to attach by a mechanism that adjusts the amount of attachment according to the conditions. Further, it is preferable to dry the recording medium after the liquid containing at least water is attached to the back side of the printing surface of the recording medium, and the heater used for drying the recording medium is also strong when a large amount of liquid is attached. When the amount is small, it is preferable to use a heater having control means such as weak heating.

According to the ink jet recording method of the present invention, the wetting time of the recording medium in the Bristow method is 30 ms or less and the absorption coefficient is 2.0 ml / m ² · ms.
By printing on a recording medium using an ink that is ^1/2 or more, curling of the recording medium after printing can be prevented.

In any of the above-described ink jet recording methods of the present invention, it is preferable that the amount of ink per ink droplet adhered to a recording medium at the time of printing is 5 g / m ² or more. The curl of the medium can be prevented even better. The adhesion amount per ink drop is a value obtained by dividing the weight per ink drop by the pixel area when the ink drop adheres to the recording medium, in g /.
It is the amount expressed in m ² .

[0010] The ink jet recording method of the present invention includes:
An ink containing water, a colorant, a water-soluble organic solvent, a surfactant, and the like can be used. By adjusting the type and content of the water-soluble organic solvent and the surfactant, recording in a desired Bristow method is performed. An ink having a wetting time to a medium and an absorption coefficient can be obtained. The wetting time and absorption coefficient of the recording medium in the Bristow method are shown in FIG.
Can be determined as follows using the permeability measuring device shown in FIG.

That is, in FIG. 1, a recording paper (My Paper, NBS Ricoh Company, Ltd.) moving an ink reservoir 2 containing 40 μl of ink for inkjet recording 1 at a specific moving speed in close contact with the peripheral surface of a rotating wheel 3. 4), and ink is absorbed on the recording paper surface through a slit (slit width 1 mm, slit length 17.5 mm) of an ink reservoir to obtain an ink transfer mark shown in FIG. 2 on the recording paper surface. The contact time t of the ink and the transfer amount V of the ink are obtained from the following equation. Contact time t (ms) = slit width d (mm) x 1000
/ Paper moving speed S (mm / sec) transfer amount V (ml / m ² ) = ink amount Q (μl) × 100
0 / (Length of ink transfer mark L (mm) x slit length w
(Mm))

By changing the moving speed of the recording paper 4, the ink contact time t and the ink transfer amount V at each moving speed are obtained. From the ink contact time t and the ink transfer amount V obtained as described above, plot V against t ^1/2 and draw an absorption curve of the ink on the recording paper as shown in FIG. Each value can be determined by setting the time during which the absorption curve is parallel to the horizontal axis as the wetting time and the slope of the absorption curve thereafter as the absorption coefficient.

The colorant for the ink used in the ink jet recording method of the present invention is a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye and an edible dye in a color index, and has a water resistance and a light resistance. It is preferable to use an excellent one. As specific examples of these dyes,
As acid dyes and food dyes, C.I. I. Acid. Yellow 17, 23, 42, 44, 79, 142, C.I. I.
Acid. Red 1,8,13,14,18,26,2
7, 35, 37, 42, 52, 82, 87, 89, 9
2,97,106,111,114,115,134,
186, 249, 254, 289, C.I. I. Acid.
Blue 9, 29, 45, 92, 249, C.I. I. Acid. Black 1, 2, 7, 24, 26, 94, C.I. I.
hood. Yellow 3, 4, C.I. I. hood. Red 7,
9, 14, C.I. I. hood. Black 1 and 2, C.I. I. direct. Yellow 1,12,2
4, 26, 33, 44, 50, 86, 120, 132,
142, 144, C.I. I. direct. Red 1,4
9,13,17,20,28,31,39,80,8
1,83,89,225,227, C.I. I. direct. Orange 26, 29, 62, 102, C.I. I. direct. Blue 1, 2, 6, 15, 22, 25, 71,
76, 79, 86, 87, 90, 98, 163, 16
5,199,202, C.I. I. direct. Black 1
9, 22, 32, 38, 51, 56, 71, 74, 7
5,77,154,168,171; C.I. I. basic. Yellow 1,2,11,13,1
4,15,19,21,23,24,25,28,2
9, 32, 36, 40, 41, 45, 49, 51, 5
3,63,64,65,67,70,73,77,8
7, 91, C.I. I. basic. Red 2,12,1
3,14,15,18,22,23,24,27,2
9, 35, 36, 38, 39, 46, 49, 51, 5
2,54,59,68,69,70,73,78,8
2, 102, 104, 109, 112, C.I. I. basic. Blue 1,3,5,7,9,21,22,26,
35, 41, 45, 47, 54, 62, 65, 66, 6
7, 69, 75, 77, 78, 89, 92, 93, 10
5,117,120,122,124,129,13
7, 141, 147, 155, C.I. I. basic. Black 2, 8, C.I. I. Reactive. Black 3, 4, 7, 11, 12, 17, C.I. I.
Reactive. Yellow 1,5,11,13,14,2
0, 21, 22, 25, 40, 47, 51, 55, 6
5,67, C.I. I. Reactive. Red 1,14,1
7, 25, 26, 32, 37, 44, 46, 55, 6
0, 66, 74, 79, 96, 97, C.I. I. Reactive. Blue 1, 2, 7, 14, 15, 23, 32, 3
5, 38, 41, 63, 80, 95 and the like. Particularly, acid dyes and direct dyes are preferred.

Dyes developed for ink-jet recording include, for example, P
rojet Fast B1ack 2, Projet F
ast Magenta 2, Projet Fast Y
yellow2, ProjetFast Cyan2 (registered trademark). Pigments can also be used as colorants, and organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine. System, rhodamine B lake pigment, carbon black, etc., and inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, navy blue, cadmium red, chrome yellow, metal powder, etc. Can be

The water-soluble organic solvent of the ink used in the ink jet recording method of the present invention is added for the purpose of preventing drying of the ink and improving the dissolution stability, and specific examples thereof include ethylene glycol. , Diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-
Polyhydric alcohols such as butanetriol, 1,2,3-butanetriol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl Ethers, polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether, etc., polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, N-methyl-2-pyrrolidone, N-hydroxyethyl -2-pyrrolidone, 2-pyrrolidone, 1,
Nitrogen-containing heterocyclic compounds such as 3-dimethylimidazolidinone and ε-caprolactam; amides such as formamide, N-methylformamide and N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine and diethylamine And amines such as triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate, and γ-butyrolactone. These solvents can be used alone or in combination of two or more.

A surfactant may be further added to the ink used in the present invention for the purpose of improving the wettability and permeability of the ink. As the surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used. Specific examples of the anionic surfactant include soap and N.
-Carboxylic acid salts such as acyl amino acid salts, alkyl ether acetates, acylated peptides, alkyl sulfonates,
Alkyl benzene sulfonate, alkyl naphthalene sulfonate, sulfosuccinate, alkyl sulfosuccinate, α-olefin sulfonate, sulfonate such as N-acyl sulfonate, sulfated oil, alkyl sulfate, alkyl Sulfuric acid ester salts such as ether carboxylate, alkyl ether sulfate, and alkyl amide sulfate; phosphate ester salts such as alkyl phosphate, alkyl ether phosphate and alkylaryl phosphate; fluoroalkyl carboxylate; Specific examples of cationic surfactants include alkyl sulfonates, fluoroalkyl phosphates, carboxylic acid-modified polydimethylsiloxanes, and sulfonic acid-modified polydimethylsiloxanes. Examples of the cationic surfactant include an aliphatic amine salt, an alkyl quaternary ammonium salt, Fluoroalkyltrimethyla Moniumu salts, aromatic amine salts,
Specific examples of amphoteric surfactants include aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts and the like, betaine types such as carboxybetaine and sulfobetaine, aminocarboxylates, imidazolines and the like. Specific examples of the ionic surfactant include ethylene oxide adducts of aliphatic alcohols, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and alkylamine oxides.

When a pigment is used as a colorant, a hydrophilic polymer can be used as a pigment dispersant. In a natural system, gum arabic, gum tragan, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin , Plant macromolecules such as quince seed starch, seaweed macromolecules such as alginic acid, carrageenan and agar, animal macromolecules such as gelatin, casein, albumin and collagen, microbial macromolecules such as xanthen gum and dextran, semi-synthetic The system includes fibrous polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose; starch polymers such as sodium starch glycolate and sodium starch phosphate; sodium alginate , Seaweed polymers such as propylene glycol alginate, vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinyl methyl ether in pure synthetic systems, non-crosslinked polyacrylamide, polyacrylic acid and alkali metal salts thereof, and water-soluble styrene acrylic. Acrylic resins such as resins, water-soluble styrene maleic acid resins, water-soluble vinyl naphthalene acrylic resins, water-soluble vinyl naphthalene maleate resins, or alkali metal salts of polyvinylpyrrolidone, polyvinyl alcohol or β-naphthalenesulfonic acid formalin condensate; Examples include a polymer compound having a salt of a cationic functional group such as a quaternary ammonium or an amino group in a side chain, and a natural polymer compound such as shellac.

The ink of the present invention may contain conventionally known additives in addition to water, a colorant, a water-soluble organic solvent, and a surfactant. For example, as preservatives and fungicides, sodium dehydroacetate, sodium sorbate,
Sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, and the like can be used. As the pH adjuster, any substance can be used as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared, and examples thereof include diethanolamine and triethanol. Amines such as amines, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, lithium carbonate, and carbonic acid Examples thereof include carbonates of alkali metals such as sodium and potassium carbonate.

Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate,
Sodium hydroxyethylethylenediaminetriacetate,
Sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like can be used.
For example, acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and the like can be used.
In addition, a water-soluble ultraviolet absorber and a water-soluble infrared absorber can be added according to the purpose.

In the ink jet recording method of the present invention, the liquid containing at least water to be adhered to the back side of the printing surface of the recording medium may be a liquid containing a water-soluble organic solvent, a surfactant or the like in addition to water. By adjusting the type and content of the water-soluble organic solvent and the surfactant, a liquid having a desired wetting time on a recording medium and an absorption coefficient in the Bristow method can be obtained.

Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexane. Polyhydric alcohols such as triol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether; Polyhydric alcohol alkyl ethers such as diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Glycol monophenyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monobenzyl ether, N- methyl-2-pyrrolidone, N- hydroxyethyl-2-pyrrolidone, 2-
Pyrrolidone, 1,3-dimethylimidazolidinone, ε-
Nitrogen-containing heterocyclic compounds such as caprolactam, amides such as formamide, N-methylformamide, and N, N-dimethylformamide; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine;
Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol, propylene carbonate, ethylene carbonate, γ-butyrolactone, and the like can be used, and these solvents can be used alone or as a mixture of two or more.

For the purpose of improving wettability and permeability, anionic surfactants, nonionic surfactants,
An amphoteric surfactant, a monohydric alcohol or the like can be added. In addition to the water-soluble organic solvent and the surfactant, an antiseptic / antifungal agent, a rust inhibitor, a water-soluble ultraviolet absorber, and a water-soluble infrared absorber can be added. As preservatives and fungicides, for example, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, etc. can be used. Sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like can be used.

[0023]

According to the ink jet recording method of the present invention, a recording medium using an ink having a wetting time of 30 ms or more in the Bristow method and an absorption coefficient of 1.9 ml / m ² · ms ^1/2 or more is used. After printing, the recording medium is prevented from curling after printing by applying a liquid containing at least water to the back side of the printing surface of the recording medium in an amount equal to or less than the amount of ink required for printing. be able to. According to the inkjet recording method of the present invention, the wetting time on the recording medium in the Bristow method is 3 hours.
0 ms or less and absorption coefficient is 2.0 ml / m ² · ms ^1/2
By printing on a recording medium using the above-described ink, curling of the recording medium after printing can be prevented.

The mechanism for curling the recording medium after printing is considered as follows. That is,
(1) By printing, only the fibers on the printing surface of the recording medium absorb ink drops and extend. (2) Cockling (wavy) because the recording medium is fixed with a platen or the like during printing
Occurs, but the recording medium is not curled as a whole. (3) When the recording medium is ejected and is no longer fixed after printing, only the fibers on the printing surface are dried and shrunk with the passage of time, so that the printing surface is concave and curls. In contrast,
According to the inkjet recording method of the present invention, the fibers on the printing surface of the recording medium and the fibers on the back side thereof are evenly stretched, so that it is considered that curling can be prevented.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Example 1 Yellow dye Projet Fast Yellow 2 (manufactured by Zeneca) 1.5
0% by weight, 0.50% by weight of IJ Yellow307H (manufactured by Daiwa), 7.50% by weight of diethylene glycol, 2.50% by weight of glycerol, 1.00% by weight of surfactant (ECTD3NEX, manufactured by Nikko Chemicals), antiseptic A composition containing 0.40% by weight of a fungicide (P-100, manufactured by San-ai Sekiyu KK) and the remaining pure water
The mixture was stirred and dissolved at 0 ° C., and allowed to cool at room temperature.
Adjust the pH to 8.5 with a 0% aqueous solution,
This was filtered through a filtration filter having an effective filtration area of 4 cm ² and a filtration pore size of 0.2 μm. Inkjet recording ink No. 1 was prepared.

The wetting time and absorption coefficient of the ink for ink jet recording on recording paper in the Bristow method were determined using this ink for ink jet recording and recording paper (My Paper, manufactured by NBS Ricoh) and the apparatus shown in FIG. . That is, in FIG. 1, an ink reservoir 2 containing 40 μl of ink for ink jet recording 1 is brought into close contact with the peripheral surface of a rotating wheel 3 and is brought into contact with a recording paper 4 moving at a moving speed of 1.25 mm / sec. Reservoir slit (slit width 1 mm, slit length 17.5 m
The ink transfer marks as shown in FIG. 2 were obtained by absorbing the ink on the recording paper surface through m), and the ink contact time t and the ink transfer amount V were determined from the following equation. Contact time t (ms) = slit width d (mm) x 1000
/ Paper moving speed S (mm / sec) transfer amount V (ml / m ² ) = ink amount Q (μl) × 100
0 / (Length of ink transfer mark L (mm) x slit length w
(Mm))

The moving speed of the recording paper 4 is 2.5 mm / sec.
5mm / sec, 12.5mm / sec, 25mm / sec, 50m
The contact time t of each ink and the transfer amount V of the ink were determined in the same manner as described above except that m / sec was used. The contact time t of each ink and the transfer amount V of the ink determined as described above.
From, V is plotted against t ^1/2 , and an absorption curve of the ink on the recording paper as shown in FIG. 3 is drawn. The time during which the absorption curve is parallel to the horizontal axis is the wetting time. Each value was determined using the following slope as an absorption coefficient. Table 1 shows the results.

Further, No. 2 was prepared in the same manner as described above except that the formulations shown in Table 1 were used. 2, 3, 4, 5, 6, 7, 8 and 9 ink jet recording inks were prepared, and the wetting time and the absorption coefficient were determined in the same manner as described above. Table 1 shows the results. Further, curling prevention liquids corresponding to the respective inks were prepared in the same manner as described above except that the yellow dye was removed from the prescriptions of the respective inks.

[0030]

[Table 1]

Next, using the ink for ink jet recording and the anti-curl liquid thus prepared, the recording paper was recorded on the recording paper by the ink jet recording apparatus schematically shown in FIG. The curl was measured. That is, in FIG. 4, the recording paper (My Paper, manufactured by NBS Ricoh Company) 5 is laterally fed between the paper presser 7 and the platen 8 by the paper feed roller 6a. Using the ink No. 1, solid printing of the print pattern shown in FIG. 5 (adhesion amount per ink drop of 4 g / m ² ) was performed by the ink jet print head 9. The printed recording paper is fed to the application roller 10 by the paper feed roller 6b, and an anti-curl liquid (liquid obtained by removing the yellow dye from the prescription of the No. 1 ink) 11 is recorded in the same amount as the solid ink adhesion amount. The recording paper was applied to the surface opposite to the printing surface of the paper, sent between the heaters 12a and 12b by the paper feed roller 6c, and dried to obtain a printed recording paper. Further, a recording paper on which printing was performed in the same manner as described above except that the amount of adhesion per ink drop was 7 g / m ² and 10 g / m ² was obtained.

On the other hand, recording papers were printed in the same manner as described above, except that the anti-curl liquid was not applied and drying by a heater was not performed. When the recording paper after printing was left in an environment of 20 ° C. and 65%, the curl of the recording paper after three minutes and one day was measured. Table 2 shows the results. In addition, No. The curl of the recording paper was measured in the same manner as described above, except that the ink jet recording inks 2, 3, 4, 5, 6, 7, 8 and 9 and the anti-curl liquids corresponding to the respective inks were used. The results are as follows:
The results are shown in Table 2 by the marks of ○, Δ, ×, and XX.

A: The paper has a curl at both front ends of less than 15 ° on average when left on a flat surface. ：: When the sheet is left standing on a flat surface, the curls at the front ends of the sheet are on average 15 ° or more and less than 30 °. C: The curl at the front both ends of the paper when left on a flat surface is 30 ° or more and less than 60 ° on average. X: The curl of the front both ends of the paper when left on a flat surface is 60 ° or more and less than 90 ° on average. XX: The curl at the front both ends of the paper when left on a flat surface is 90 ° or more on average.

[0034]

[Table 2]

As is apparent from Table 2, the wettability of the recording paper in the Bristow method was 30 ms or more and the absorption coefficient was 1.9 ml / m ² · ms ^1/2 or more. 1,
After printing on the recording paper using inks 2, 3, 4, 5, and 6, the anti-curl liquid obtained by removing the dye from the ink formulation is equal to the amount of ink required for printing on the back side of the printing surface of the recording paper. When the ink is applied in an amount, the curling of the recording paper can be prevented more than when the anti-curl liquid is not applied. In particular, the wetting time on the recording paper in the Bristow method is 50 ms or more, and the absorption coefficient is 2.0 ml / m ^2.
· Ms ^1/2 greater than or equal is No. When printing is performed in the same manner as described above using inks 2, 3, and 4 and the anti-curl liquid is applied, curling of the recording paper can be better prevented.

The wetting time on the recording paper in the Bristow method is 30 ms or less and the absorption coefficient is 2.0 ml /
m ² · ms ^1/2 or more. When printing is performed on the recording paper using the inks 7 and 8, the curl of the recording paper can be better prevented regardless of the presence or absence of the curl prevention liquid. In any of the above cases, the amount of ink deposited on the recording medium per drop of ink was 5 g.
/ M ² or more, the curl of the recording paper can be better prevented.

Example 2 The procedure of Example 1 was repeated except that the formulations shown in Table 3 below were used. 10, 11, 12, 13, 14, 15, 16,
Ink jet recording inks Nos. 17 and 18 were prepared, and the wetting time and the absorption coefficient were determined in the same manner as in Example 1. Table 3 shows the results. Further, curling prevention liquids corresponding to the respective inks were prepared in the same manner as described above except that the magenta dye was excluded from the formulation of the respective inks. next,
The curl of the recording paper was measured in the same manner as in Example 1 except that the ink for ink jet recording and the curl preventing liquid thus prepared were used. Table 4 shows the results.

[0038]

[Table 3]

[0039]

[Table 4]

As is clear from Table 4, the wettability of the recording paper in the Bristow method was 30 ms or more and the absorption coefficient was 1.9 ml / m ² · ms ^1/2 or more. 1
After printing on recording paper using the inks of 0, 11, 12, 13, 14, and 15, the amount of ink required for printing on the back side of the printing surface of the recording paper was coated with an anti-curl liquid obtained by removing the dye from the ink formulation. When the same amount is applied, curling of the recording paper can be prevented as compared with the case where the anti-curl liquid is not applied. In particular, No. 3 has a wetting time on recording paper of 50 ms or more and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. 11, 1
When printing is performed in the same manner as described above using the inks 2 and 13 and the anti-curl liquid is applied, the curl of the recording paper can be better prevented.

The wetting time on the recording paper in the Bristow method is 30 ms or less and the absorption coefficient is 2.0 ml /
m ² · ms ^1/2 or more. When printing is performed on the recording paper using the inks 16 and 17, the curl of the recording paper can be better prevented regardless of the presence or absence of the curl prevention liquid. Also, in any of the above cases,
The curl of the recording paper can be better prevented by setting the amount of ink per ink drop to the recording medium in printing at 5 g / m ² or more.

Example 3 The procedure of Example 1 was repeated except that the formulation shown in Table 5 was used.
o. 19, 20, 21, 22, 23, 24, 25, 26
And 27 were prepared, and the wetting time and the absorption coefficient were determined in the same manner as in Example 1.
Table 5 shows the results. Further, an anti-curl liquid corresponding to each ink was prepared in the same manner as described above except that the cyan dye was removed from the formulation of each ink. Next, the curl of the recording paper was measured in the same manner as in Example 1 except that the ink for ink jet recording and the curl preventing liquid thus prepared were used. Table 6 shows the results.

[0043]

[Table 5]

[0044]

[Table 6]

As is clear from Table 6, in the Bristow method, the wetting time on the recording paper was 30 ms or more and the absorption coefficient was 1.9 ml / m ² · ms ^1/2 or more. 1
After printing on recording paper using the inks of 9, 20, 21, 22, 23, and 24, the amount of ink required for printing on the back side of the printing surface of the recording paper was coated with an anti-curl liquid obtained by removing the dye from the ink formulation. When the same amount is applied, curling of the recording paper can be prevented as compared with the case where the anti-curl liquid is not applied. In particular, No. 3 has a wetting time on recording paper of 50 ms or more and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. 20, 2
When printing is performed in the same manner as described above using the inks of Nos. 1 and 22 and the anti-curl liquid is applied, the curl of the recording paper can be better prevented.

The wetting time on the recording paper in the Bristow method is 30 ms or less and the absorption coefficient is 2.0 ml /
m ² · ms ^1/2 or more. When printing is performed on recording paper using the inks 25 and 26, curling of the recording paper can be better prevented regardless of the presence or absence of the curl prevention liquid. Also, in any of the above cases,
The curl of the recording paper can be better prevented by setting the amount of ink per ink drop to the recording medium in printing at 5 g / m ² or more.

[0047]

According to the ink jet recording method of the present invention, curling of the recording medium after printing can be prevented. Further, the inkjet recording ink of the present invention,
The use of the curl preventing liquid can prevent the recording medium from curling after printing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a permeability measuring apparatus by the Bristow method.

FIG. 2 is an explanatory diagram showing ink transfer marks by the Bristow method.

FIG. 3 is an explanatory diagram showing an absorption curve of recording ink for ink by the Bristow method.

FIG. 4 is a cross-sectional view schematically illustrating an example of an ink jet recording apparatus that performs the ink jet recording method of the present invention.

FIG. 5 is an explanatory diagram showing an example of a print pattern printed by the inkjet recording method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Ink for inkjet recording 2 Ink reservoir 3 Rotating wheel 4 Recording paper 5 Recording paper 6a Paper feed roller 6b Paper feed roller 6c Paper feed roller 7 Paper holder 8 Platen 9 Inkjet print head 10 Application roller 11 Anti-curl liquid 12a Heater 12b Heater

Continuing from the front page (72) Inventor Akiko Konishi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Hirotaka Mochizuki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Masayuki Koyano 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Takanori Tsuki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Ikuko Tanaka 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (11)

[Claims] In an ink jet recording method, printing is performed on a recording medium using an ink having a wetting time of 30 ms or more and an absorption coefficient of 1.9 ml / m ² · ms ^1/2 or more in the Bristow method. Thereafter, a liquid containing at least water is applied to the back side of the printing surface of the recording medium in an amount equal to or less than the amount of ink required for printing. 2. In an ink jet recording method, printing is performed on a recording medium using an ink having a wetting time of 50 ms or more and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. Thereafter, a liquid containing at least water is applied to the back side of the printing surface of the recording medium in an amount equal to or less than the amount of ink required for printing. 3. The method according to claim 1, wherein the wetting time of the liquid containing at least water to the recording medium in the Bristow method is 30 ms or more and the absorption coefficient is 1.9 ml / m ² · ms ^1/2 or more. The ink-jet recording method as described above. 4. The method according to claim 2, wherein the wetting time of the liquid containing at least water to the recording medium in the Bristow method is 50 ms or more, and the absorption coefficient is 2.0 ml / m ² · ms ^1/2 or more. The ink-jet recording method as described above. 5. The ink jet recording method according to claim 1, wherein the liquid containing at least water comprises a component obtained by removing a coloring material from the ink composition. 6. The recording medium according to claim 1, wherein the recording medium is dried after a liquid containing at least water is attached.
The inkjet recording method according to 2, 3, 4, or 5. 7. In an ink jet recording method, printing is performed on a recording medium using an ink having a wetting time of 30 ms or less and an absorption coefficient of 2.0 ml / m ² · ms ^1/2 or more in the Bristow method. An ink-jet recording method, characterized in that: 8. The ink-jet recording according to claim 1, wherein an amount of ink per ink droplet attached to a recording medium in printing is 5 g / m ² or more. Method. 9. The wetting time for a recording medium in the Bristow method is 30 ms or less and the absorption coefficient is 2.0 ml / m ^2.
-An ink jet recording ink characterized by having a ms ^1/2 or more. 10. An anti-curl liquid for ink-jet recording, comprising a component obtained by removing a coloring material from an ink composition. 11. The wetting time on a recording medium in the Bristow method is 50 ms or more, and the absorption coefficient is 2.0 ml / m.
^An anti-curl liquid for ink jet recording, characterized by having a time of ² ms ^1/2 or more.