JP2007152769A - Inkjet image recording method and inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed inkjet image recording method in which a surface drying performance is high even when a large quantity of ink is placed, cockling and curling are avoided, and strike-through is hardly generated, and to provide an inkjet printer. <P>SOLUTION: In the inkjet image recording method, printing is carried out by using an inkjet ink which includes water by 10-45% and a solvent by 50-90%. The solvent has a surface tension at 25°C of not smaller than 25 mN/m and not larger than 40 mN/m, a viscosity at 25°C of not smaller than 1 mPa s and not larger than 50 mPa s, and a vapor pressure at 25°C of not larger than 133 Pa. In this case, infrared rays are irradiated after printing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet image recording method capable of high-quality double-sided printing, and an inkjet printer.

  In recent years, the ink jet recording system can create images easily and inexpensively, and thus has been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters. In particular, ink jet recording devices that emit and control fine dots, ink with improved color reproduction gamut, durability, and emission suitability, ink absorbency, coloring material color development, surface gloss, etc. are dramatically improved. It is also possible to obtain image quality comparable to silver halide photography using special paper.

  However, in an inkjet image recording system that requires dedicated paper, there are problems in that the recording media that can be used are limited and the cost of the recording media is increased.

  On the other hand, in the office, there is an increasing need for a system capable of performing full color printing at high speed without being restricted by a recording medium (for example, plain paper, coated paper, art paper, plain paper double-sided printing, etc.).

  As for the composition of the ink-jet ink, it can be printed at high speed, has good character reproducibility on plain paper, and shows through when printing (the phenomenon that the printed ink passes through the recording medium and the image appears on the back), feathering Various studies have been made from the viewpoints of no occurrence of image bleeding, rapid penetration into paper, and quick drying.

  In particular, for inkjet recording devices intended for double-sided printing, when double-sided printing is performed on plain paper, if the back-through on printing is large, the back-through image overlaps with the printed content on the back, making it very difficult to see. End up.

  On the other hand, in the case of a printing form with high-speed printing in mind, the printed material is overlaid immediately after printing, and the ink of the lower paper is reflected on the back surface of the upper paper, so the surface dryness of the printed material is required. At the same time, printed materials without curling and cockling are required to prevent paper jams during high speed conveyance.

  As a means for improving the surface drying property of a printed matter, a method of providing a drying means is disclosed (for example, Patent Document 1). According to this, by drying with infrared rays, even slow-drying ink can be dried in a short time, and high-speed printing can be achieved. However, the above method has a problem of curling due to drying.

  On the other hand, a method of providing a mechanism for correcting curl caused by drying is disclosed (for example, Patent Documents 2 and 3). In these methods, it takes time to correct the curl, and additional mechanisms are added to the apparatus and the size is increased. It is not suitable for the specifications, and the cost burden is large.

  On the other hand, as a means for improving the surface drying property of the printed matter, a method of giving the ink surface drying property has been devised. As a method for achieving both the emission stability and the surface drying property, a method for improving the surface drying property by increasing the permeability of the ink into the paper and realizing high-speed printing is disclosed. For example, Patent Document 4 discloses an ink that defines a wetting time by the Bristow method.

  However, when ink with high penetrability is used, there is a problem that the ink coloring material easily penetrates into the inside of the paper, the back-through becomes large, and the printing quality is deteriorated when printing on both sides of the paper.

  Further, solvent-based inks that can perform printing at high speed instead of water-based inkjet inks have been studied. That is, by using an oil-based ink (solvent ink jet ink) that contains a volatile solvent and has improved drying properties, even when printing on plain paper, the penetration into the recording medium is fast and the drying time is short. High-speed printing is possible without curling or the like. However, solvent-based inks also have high penetrability inside the paper, causing back-through, which has been a major obstacle especially when printing on both sides of plain paper.

  In order to solve the above-mentioned problems, there has been proposed an ink in which a solvent satisfying a specific condition and water are mixed as a solvent that satisfies both prevention of back-through and prevention of curling and has high surface drying properties (for example, Patent Document 5). Thus, it is described that while the permeability is high and the surface drying property is high, it is possible to obtain a printed matter that does not cause curl and cockling while having high anti-through-through performance.

However, if the amount of ink is increased for the purpose of printing photographs and drawings with many intermediate colors with high image quality, cockling can be sufficiently suppressed even if the ink presented in Patent Document 5 is used. Further, it was found that the surface dryness was insufficient.
JP 63-252772 A JP 2001-301151 A JP 2002-187264 A JP 10-316915 A JP 2005-220296 A

  Accordingly, an object of the present invention is to provide a high-speed inkjet image recording method and an inkjet printer that have high surface drying properties even when a large amount of ink is ejected, are free from cockling and curling, and are difficult to cause back-through.

  The above object of the present invention is achieved by the following means.

  1. A solvent having a water tension of 10 to 45%, a surface tension at 25 ° C. of 25 mN / m to 40 mN / m, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. of 133 Pa or less. An inkjet image recording method for performing printing using an inkjet ink containing 50 to 90%, wherein infrared irradiation is performed after printing.

  2. A solvent having a water tension of 10 to 45%, a surface tension at 25 ° C. of 25 mN / m to 40 mN / m, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. of 133 Pa or less. An ink jet printer that performs printing using an ink jet ink containing 50 to 90% of an ink jet ink, comprising an infrared irradiation means.

  According to the present invention, a high-speed ink jet image recording method and an ink jet printer that have high surface dryness even when a large amount of ink is ejected, are free from cockling and curling, and are difficult to cause back-through are obtained.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The present invention has a water content of 10 to 45%, a surface tension at 25 ° C. of 25 mN / m to 40 mN / m, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. of 133 Pa. Infrared irradiation is performed after printing by an inkjet method using an inkjet ink containing 50 to 90% of the following solvent.

  According to the above-described configuration of the present invention, it is possible to provide a printed matter that is free from curling and cockling and has no problem with surface drying by further drying the ink that does not easily cause curling or cockling. is there. In addition, although not expected by the present researchers, it was found that curling and cockling of the printed matter is further improved by drying with the above configuration.

  An ink that satisfies the requirements of the present invention not only has a small degree of swelling of paper but also a slow speed of swelling compared with an ink having a high water ratio. For this reason, when infrared drying is performed, drying in a solvent is performed before the swelling of the paper reaches equilibrium, and it is considered that curling and cockling are improved. On the other hand, in the ink containing water as the main solvent, the swelling of the paper fiber occurs first. Therefore, when drying is performed as described in JP-A-2001-301151 and JP-A-2002-187264, curling and cockling are improved. , The phenomenon that the curl gets worse.

  The invention will be described in detail below.

  First, the plain paper in the present invention will be described. Examples of the plain paper in the present invention include what are generally called high-quality paper, neutral paper, and copy paper. When a recording sheet or paper is used in the text, it means plain paper.

  Next, the ink used in the present invention will be described.

  The surface tension at 25 ° C. used in the present invention is 25 mN / m or more and 40 mN / m or less, the viscosity at 25 ° C. is 1 mPa · s or more and 50 mPa · s or less, and the vapor pressure at 25 ° C. is 133 Pa or less. The solvent which is is demonstrated.

  As described above, in the solvent (aqueous solvent) according to the present invention, as one requirement, the surface tension at 25 ° C. is 25 mN / m or more and 40 mN / m or less, preferably 25 mN / m or more. 32 mN / m or less.

  As for the surface tension of the solvent, the surface tension of various organic compounds is described in Rev. 3rd edition, Chemical Handbook, Basic Edition, Chemical Society of Japan, II-82, and can be referred to. However, CBVP manufactured by Kyowa Interface Science Co., Ltd. It can be measured (25 ° C.) using a type surface tension meter A3 type or the like.

  In addition, regarding the vapor pressure, the revised third edition Chemical Handbook Basic Edition, The Chemical Society of Japan, II-119 describes the parameters for calculating the vapor pressure of various organic compounds according to the Harlacher-Braun equation, Can be calculated.

  In addition, the viscosity at 25 ° C. is one of the characteristics that it is 1 mPa · s or more and 50 mPa · s or less, and preferably 1 mPa · s or more and 30 mPa · s or less. Moreover, although it is one of the characteristics that the vapor pressure in 25 degreeC is 133 Pa or less, Preferably it is 1-67 Pa. The viscosity can be measured (25 ° C.) with a commercially available viscometer, for example, a vibration viscometer Viscomate VM-1A-L (manufactured by Yamaichi Electronics Co., Ltd.).

  The solvent (aqueous solvent) that can be used in the present invention is not particularly limited as long as it satisfies all the three liquid properties defined above. For example, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, Propylene glycol monobutyl ether, dipropylene glycol monomethyl ether , Dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, diethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, tetrapropylene glycol monomethyl ether , Diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dibutyl ether, 2-methyl-2,4-pentanediol, diethylene glycol monoethyl ether Or the like can be mentioned acetate.

  In the inkjet ink according to the present invention, a surfactant can be used as an additive during dispersion. As the surfactant used in the present invention, any of cationic, anionic, amphoteric and nonionic can be used.

  Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like.

  Examples of the anionic surfactant include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, acylated peptide, alkyl sulfonate, Alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate, secondary higher alcohol Sulfate ester, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglyculate, fatty acid alkylolamide sulfate, alkyl ether phosphate ester, alkyl phosphate ester Examples include tellurium salts.

  Examples of amphoteric surfactants include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like.

  Nonionic activators include polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, Oxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, polyoxyethylene Fatty acid amide, polyoxyethylene alkylamine, alkylamine oxide, acetyl Glycol, acetylene alcohol, and the like.

  Further, it is preferable to use a surfactant in order to accelerate the penetration of ink droplets after ink ejection into plain paper, and such a surfactant has an adverse effect on the ink, such as storage stability. The surfactant is not limited as long as it does not affect the surface, and the same surfactants as those used as an additive at the time of dispersion can be used.

  Further, in the ink used in the present invention, the total content of calcium ions, magnesium ions and iron ions, which are polyvalent metal ions of the ink, is preferably 10 ppm or less, more preferably 0.1 to 0.1 ppm. 5 ppm, particularly preferably 0.1 to 1 ppm.

  By setting the content of polyvalent metal ions in the inkjet ink to the amount specified above, an ink having high dispersion stability can be obtained. The polyvalent metal ion according to the present invention is contained in sulfates, chlorides, nitrates, acetates, organic ammonium salts, EDTA salts and the like.

  In the ink used in the present invention, in addition to the above description, according to the purpose of improving the emission stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performances as necessary. Various known additives such as polysaccharides, viscosity modifiers, specific resistance regulators, film forming agents, ultraviolet absorbers, antioxidants, anti-fading agents, anti-fouling agents, rust inhibitors, etc. For example, oil droplet fine particles such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, ultraviolet absorption described in JP-A-57-74193, 57-78988 and 62-261476 Agent, JP-A-57-74192, JP-A-57-87989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091 and JP-A-3-1337. Fluorescent dyes described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, JP-A-4-219266, etc. A brightener and the like can be mentioned.

  The ink of the present invention contains a colorant and further additives as described later in the above solvent as necessary. Examples of the hue of the colorant used in the present invention include yellow and magenta. , Cyan, black, blue, green, and red are preferably used, and yellow, magenta, cyan, and black colorants are particularly preferable.

  The ink used in the present invention is a dye ink whose colorant is a dye, or a pigment ink containing fine pigment particles in which a colorant is insoluble in a solvent constituting an ink-jet ink and forming a dispersion system, or a colorant The present invention can be applied to various ink-jet inks such as a dispersion ink composed of a dispersion of a polymer polymer colored.

  Examples of the dye that can be used in the present invention include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, diphenylmethane dyes, and the specific compounds include: For example, the dye illustrated in Unexamined-Japanese-Patent No. 2002-264490 can be mentioned.

  In addition, for oil-soluble dyes that form colored fine particles together with the polymer or the like and serve as a colorant, they are usually soluble in organic solvents that do not have a water-soluble group such as carboxylic acid and sulfonic acid and are insoluble in water, such as dispersed A dye or the like is selected. Also included are dyes that exhibit oil solubility by salting a water-soluble dye with a long-chain base. For example, acid dyes, direct dyes, salt-forming dyes of reactive dyes and long-chain amines are known. .

  However, in the ink used in the present invention, it is preferable to use a pigment as a colorant, and a pigment having no solubility in the solvent system is preferable from the viewpoint of exerting the intended effect of the present invention.

  As the pigment that can be used in the present invention, conventionally known pigments can be used without particular limitation, and any of water-dispersible pigments, solvent-dispersible pigments, and the like can be used, for example, organic pigments such as insoluble pigments and lake pigments, An inorganic pigment such as carbon black can be preferably used.

  The insoluble pigment is not particularly limited. Dioxazine, thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 15: 3, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

In addition to the above, when red, green, blue and intermediate colors are required, the following pigments are preferably used alone or in combination. I. Pigment Red; 209, 224, 177, 194,
C. I. Pigment Orange; 43,
C. I. Vat Violet; 3,
C. I. Pigment Violet; 19, 23, 37,
C. I. Pigment Green; 36, 7,
C. I. Pigment Blue; 15: 6,
Etc. are used.

  Examples of black pigments include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  The pigment used in the present invention is preferably used after being dispersed by a disperser together with a dispersant and other necessary additives according to desired purposes. As the disperser, a conventionally known ball mill, sand mill, line mill, high-pressure homogenizer, or the like can be used.

  The average particle size of the pigment dispersion used in the ink used in the present invention is preferably 10 nm to 200 nm, more preferably 10 nm to 100 nm, and still more preferably 10 nm to 50 nm. If the average particle size of the pigment dispersion exceeds 100 nm, the dispersion becomes unstable. In addition, even when the average particle size of the pigment dispersion is less than 10 nm, the stability of the pigment dispersion tends to deteriorate, and the storage stability of the ink tends to deteriorate.

  The particle size of the pigment dispersion can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. It is also possible to obtain a particle image with a transmission electron microscope on at least 100 particles and perform statistical processing on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). Is possible.

  The infrared irradiation means in this invention is demonstrated.

  In the present invention, the infrared rays may be either near infrared rays or far infrared rays, and light falling within a wavelength range of 0.1 μm to 1 mm is infrared rays.

  In order to obtain the infrared radiation used in the present invention, it may be obtained directly from a heat source or through a heat medium, effective infrared radiation may be generated therefrom. For example, an infrared ray may be obtained by heating a discharge lamp such as mercury, xenon, cesium, or sodium, or a carbon dioxide laser, or an electric resistor such as platinum, tungsten, nichrome, or cantal. A specifically preferred apparatus is a halogen lamp. Halogen lamps have advantages such as good thermal efficiency and quick start-up.

  The infrared heating device preferably has a power of 200 to 800W. When the power is 200 W or higher, vaporization of the organic solvent remaining in the recording medium is promoted. When the power exceeds 800 W, the irradiation conditions are severe and there is a risk of causing burns on the paper.

  Regarding the infrared irradiation, the surface temperature of the irradiated paper is preferably in the range of 80 to 200 ° C. If it is 80 degreeC or more, drying is quick and the reduction effect of cockling is large. When the temperature is 200 ° C. or lower, the paper does not ignite even when the conveyance is stopped for some reason.

  Irradiation with infrared rays may be performed from the printing surface side or from the back surface side. If there is no restriction on the apparatus and cost, it is desirable to perform irradiation from both sides simultaneously in terms of the effect of the present invention. It is preferable to combine with temperature rising drying or air drying if possible. Further, it is more preferable to use a light collector if necessary.

  In the ink jet image recording method of the present invention, for example, by using a printer loaded with the ink jet ink according to the present invention, ink is ejected as droplets from an ink jet head based on a digital signal, and is attached to plain paper for printing. Is obtained.

  In the inkjet image recording method of the present invention, the inkjet head to be used may be an on-demand system or a continuous system. Also, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, thermal ink jet) Any ejection method such as a mold, a bubble jet (registered trademark) mold, or the like may be used.

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

Examples [Preparation of Pigment Dispersion A]
15 parts by mass of MA100 (Mitsubishi Carbon Black MA100, manufactured by Mitsubishi Chemical Corporation) as a pigment, 15 parts by mass of Jonkrill 501 (manufactured by Johnson Polymer) as a dispersion resin, 5 parts by mass of tripropylene glycol monmethyl ether (TPGME), water After mixing 65 parts by mass, 200 parts by mass of zirconia beads having a diameter of 0.5 mm were placed in a polypropylene plastic bottle and sealed, and dispersed for 5 hours in a paint shaker to obtain a black pigment dispersion A. .

[Preparation of ink A]
A solvent and water were added to the plastic bottle containing the dispersion so as to have the following combination, and the mixture was stirred for about 30 minutes with a paint shaker. In addition, the numerical value of addition amount represents the mass part. Thereafter, the beads were removed, and filtration and membrane deaeration treatment using a hollow fiber membrane were performed to prepare ink A.
Tripropylene glycol monomethyl ether 230 parts by weight Water 45 parts by weight Pigment dispersion A 100 parts by weight [Preparation of ink B]
The pigment dispersion A, the solvent and water were mixed in the following proportions and stirred for about 30 minutes with a paint shaker. The numerical value of the addition amount represents parts by mass. Thereafter, the beads were removed, and filtration and membrane deaeration treatment using a hollow fiber membrane were performed to prepare ink B.
Dipropylene glycol monomethyl ether 230 parts by weight Water 45 parts by weight Pigment dispersion A 100 parts by weight [Preparation of ink C]
The pigment dispersion A, the solvent and water were mixed in the following proportions and stirred for about 30 minutes with a paint shaker. The numerical value of the addition amount represents parts by mass. Thereafter, the beads were removed, and filtration and membrane deaeration treatment using a hollow fiber membrane were performed to prepare ink C.
2-Methyl-2,4-pentanediol 200 parts by mass Water 75 parts by mass Pigment dispersion A 100 parts by mass [Preparation of Ink D]
The pigment dispersion A, the solvent and water were mixed in the following proportions and stirred for about 30 minutes with a paint shaker. The numerical value of the addition amount represents parts by mass. Thereafter, the beads were removed, and filtration and membrane deaeration treatment using a hollow fiber membrane were performed to prepare ink D.
Triethylene glycol monobutyl ether 15 parts by mass Water 260 parts by mass Pigment dispersion A 100 parts by mass << Inkjet image recording >>
[Image recording]
Using a shuttle head type piezo-type recording head having a nozzle diameter of 25 μm and a nozzle number of 512, the recording resolution is 1440 × 1440 dpi (in the present invention, dpi represents the number of dots per 2.54 cm), ink A black solid image with an image size of 280 × 200 mm is printed on one side of business-class plain paper made by Konica Minolta Business Technology, Inc. using inks A to D under the condition that the adhesion amount is 16 ml / m ² . went. The sample moved to a dry space within 3 seconds after completion of printing, and was irradiated with infrared rays for 20 seconds from a 2 cm upper portion of the paper with a 400 W halogen lamp to obtain Samples 1 to 4. At this time, the surface temperature of each sample at the time point of 15 seconds from the start of drying was measured with an infrared thermometer (IT2-80, manufactured by Keyence Corporation), and all were 95 ° C.

On the other hand, using a shuttle head type piezo-type recording head having a nozzle diameter of 25 μm and a nozzle number of 512, recording resolution is 1440 × 1440 dpi, ink adhesion amount is 16 ml / m ² , and inks A to D are used. Black solid images with an image size of 280 × 200 mm were printed on one side of A4 size Konica Minolta Business Technology business class plain paper to obtain Samples 5-8.

  Table 1 shows the correspondence between the sample numbers and the ink numbers.

<Curl cockling evaluation>
When each sample was irradiated with infrared rays immediately after printing, each curl and cockling was measured immediately after irradiation. As an evaluation method, the sample was placed on a flat horizontal surface, and the height of the part that floated most from the horizontal surface was set as an evaluation value by a laser displacement meter.

◎: Lift from the horizontal plane is less than 1 mm ○: Lift from the horizontal plane is 1 mm or more and less than 2 mm △: Lift from the horizontal plane is 2 mm or more and less than 3 mm ×: Lift from the horizontal plane is 3 mm or more and less than 5 mm XX: Lift from the horizontal plane is 5 mm or more. Or curled and curled.

<Surface dryness evaluation (suitable for high-speed printing)>
Immediately after printing, when each sample was irradiated with infrared rays, unprinted paper was layered on the sample immediately after irradiation, and rubbed by rubbing from the top to examine the adhesion of ink from the sample to the stacked paper.

  ○: Not attached at all.

×: Ink adherence is partially observed. ××: Ink adherence is observed in an area of 3% or more of the paper surface.

<Betrayal evaluation>
Each sample was visually evaluated for see-through, but there was no noticeable see-through in any of the samples.

  From the above results, it can be seen that inks A, B, and C satisfying the requirements of the present invention are improved not only in surface dryness but also in curled cockling by performing infrared irradiation which is an element of the present invention.

  With the above method, there is provided an ink jet recording method which has no show-through in the configuration of the present invention, no curling or cockling, high surface dryness and high suitability for high-speed printing.

Claims (2)

A solvent having a water tension of 10 to 45%, a surface tension at 25 ° C. of 25 mN / m to 40 mN / m, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. of 133 Pa or less. An inkjet image recording method for performing printing using an inkjet ink containing 50 to 90%, wherein infrared irradiation is performed after printing. A solvent having a water tension of 10 to 45%, a surface tension at 25 ° C. of 25 mN / m to 40 mN / m, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. of 133 Pa or less. An ink jet printer that performs printing using an ink jet ink containing 50 to 90% of an ink jet ink, comprising an infrared irradiation means.