JP2007152872A - Inkjet recording method and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method which prevents strike-through regardless of paper kinds, prevents a printing density from being lowered more than necessary, and is high in high-speed printing characteristics. <P>SOLUTION: In the inkjet recording method, an image is formed by supplying to both faces of a recording medium an inkjet ink which includes water of 10-45 mass% and a solvent of 50-90 mass%. 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 the inkjet recording method, a transmission amount of light of the recording medium is measured, and control of a supply amount of the inkjet ink to the recording medium is carried out according to the measured transmission amount of the light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In recent years, the inkjet recording method can be easily and inexpensively produced images, 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 print at high speed, has good character reproducibility on the recording medium, and shows through when printing (a phenomenon in which the printed ink passes through the recording medium and the image is reflected 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, with respect to inkjet recording apparatuses intended for double-sided printing, when double-sided printing is performed on a recording medium, if the back-through of the printing is large, the back-through image overlaps with the printed content on the back, resulting in very difficult to see printing. End up.

  On the other hand, in the case of a printing form with high-speed printing in mind, the printed matter is superimposed immediately after printing, and the ink of the lower paper is reflected on the back surface of the upper paper, so that the surface drying property of the ink is required.

  If an ink that uses a liquid with a high vapor pressure as a solvent is selected as the ink with a high surface drying property, the ink transfer due to the overlap of printed matter can be suppressed, but the head maintenance and output stability will be impaired. It is not suitable for high-speed printing applications such as heads that require emission stability.

  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 employed. However, when ink with high penetrability is used, the ink color material easily penetrates into the inside of the paper, the back-through becomes large, and when double-sided printing is performed, the print quality is deteriorated. Therefore, it is necessary to have a technique for controlling the show-through caused by the penetration of the ink coloring material when a highly penetrating ink is used.

  Causes of the show-through include 1) information on the front surface can be seen through due to the transparency of the paper itself, and 2) a case where the color material has penetrated to the vicinity of the back surface.

  With regard to 1), Japanese Patent Application Laid-Open No. 7-314734 provides density selection means, and when double-sided printing is performed, the density is lowered to prevent back-through. Furthermore, considering the versatility of the recording medium, the thickness of the recording paper is measured, and based on the value, the ink supply amount that does not cause the back-through is read out from the table measured in advance, and the back-through of various types of paper is detected. There is known a recording method capable of easily creating a printed matter that does not occur (see Patent Document 1).

  However, even with paper of the same thickness, the degree of strikethrough varies depending on the additive and paper density of the paper, so it is particularly common to control the strikethrough by controlling the ink supply only from the thickness. It was insufficient to detect the difference in recording media used in the office and control the show-through without reducing the surface density more than necessary.

On the other hand, with respect to 2), there is known an ink characterized in that a solvent satisfying specific conditions and water are used as a solvent that is suitable for recording medium duplex printing and does not cause cockling (see Patent Document 2). . As a result, penetrating performance close to that of water-based ink having low penetrability is achieved while having high penetrability. However, even when these inks are used, it is insufficient to control the show-through without lowering the surface density more than necessary.
JP 2002-137382 A JP 2005-220296 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording method that does not show through regardless of the type of paper, does not unnecessarily reduce print density, and has high-speed printing characteristics.

1. It contains 10 to 45% by mass of water, has a surface tension at 25 ° C. of 25 mN / m or more and 40 mN / m or less, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. An ink jet recording method for forming an image by supplying an ink jet ink containing 50 to 90% by mass of a solvent of 133 Pa or less to both sides of a recording medium, measuring the light transmission amount of the recording medium, and measuring the light An ink jet recording method, comprising: controlling an ink jet ink supply amount to the recording medium in accordance with a transmission amount.
2. 2. The ink jet recording method according to item 1, wherein the control is performed based on a back-through limit amount obtained from a relationship between a light transmission amount obtained in advance and a supply amount of the ink jet ink.
3. 3. The ink jet recording method according to 2, wherein the control is performed by determining a maximum supply amount based on the back-through limit amount.
4). 4. An ink jet recording apparatus used in the ink jet recording method according to 3 above, wherein a light source capable of irradiating light transmitted through the recording medium and a measuring instrument for measuring the amount of transmitted light transmitted through the recording medium are measured. And an ink jet recording apparatus comprising: a means for controlling a maximum ink supply amount according to the measured numerical value of the light transmission amount.

  With the above-described configuration of the present invention, there can be provided an ink jet recording method that does not show through regardless of the paper type, does not unnecessarily reduce the print density, and has high-speed printing characteristics.

  The present invention contains 10 to 45 mass% of water, has 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 25 ° C. An ink jet recording method for forming an image by supplying an ink jet ink containing 50 to 90% by mass of a solvent having a vapor pressure of 133 Pa or less to both sides of a recording medium, and measuring a light transmission amount of the recording medium The ink jet ink supply amount to the recording medium is controlled according to the measured light transmission amount.

In the present invention, in particular, the specific ink is used to measure the light transmission amount of the recording medium that is a recording medium, and the ink supply amount (ejection amount) at the time of recording is controlled according to the measured light transmission amount. Therefore, there is no show-through regardless of the paper type, and it is possible to provide an ink-jet recording method with high-speed printing characteristics without lowering the print density more than necessary. According to the numerical value of the light transmission amount of the recording medium serving as the recording medium The reason why it is possible to control the back-through is to contain 10 to 45% by mass of water, the surface tension at 25 ° C. is 25 mN / m or more and 40 mN / m or less, and the viscosity at 25 ° C. is 1 mPa · s or more and 50 mPa · s or less. And when using an inkjet ink containing 50 to 90% by mass of a solvent having a vapor pressure at 25 ° C. of not more than 133 Pa, particularly when recording on a recording medium as a recording medium, This is presumed to be due to the high correlation between the light transmittance of the recording medium and the back-through performance. The reason for this high correlation is presumably because the colorant itself tends to remain in the vicinity of the paper surface (printing surface) despite the high solvent permeability.

  The content of the solvent having the above-described conditions according to the present invention is required to be 50 to 90% by mass with respect to the total amount of the ink-jet ink in terms of prevention of the back-through and the correlation between the back-through and the light transmission amount with respect to the total amount of the ink-jet ink. It is particularly preferable that it is 55 to 80% by mass.

  Details of the present invention will be described below.

  The recording medium according to the present invention is a sheet-like material that can hold ink-jet ink, and the effect of the present invention is particularly great in the case of paper, and is particularly large in the case of plain paper. Examples of plain paper include what are generally called high-quality paper, neutral paper, and copy paper.

  The light transmission amount of the recording medium in the present invention is a value that represents the intensity of light that passes through the recording medium and exits from the opposite side when the recording medium is irradiated with light of a certain intensity from one side of the recording medium.

  “Depending on the amount of transmitted light” means based on the value of the amount of transmitted light itself or the value of the ratio of irradiated light to transmitted light.

  For example, in the embodiment of the present invention, the absorbance that can be calculated by Equation 1 is used, and the value of the ratio between the irradiated light and the transmitted light is used.

Formula 1 Abs = log (I0 / I)
Abs: Absorbance I0: Light intensity determined by the light source I: Light intensity after passing through the paper The value of the transmitted light intensity of the paper may be directly used without using the absorbance.

  The light transmission amount of paper is measured by a device that has a light source and a measuring device that can measure the intensity of light, and is configured so that light emitted from the light source passes through the paper and enters the measuring device. be able to.

  Although it does not specify as a light source in particular, what has intensity | strength in a visible light region is preferable. More preferably, the strength is in the range of 500 nm to 600 nm.

  As long as the measuring device can measure the intensity of the wavelength range of the light source, there is no particular designation of the type. The measurement range is preferably in the range of 400 nm to 650 nm, and more preferably in the range of 500 to 600 nm.

  The light intensity may be measured by measuring the intensity of only a specific wavelength or by integrating the intensity over a specific range.

  Alternatively, the concentration control mechanism may be made independent by measuring the intensity of transmitted light for each color by using the wavelength corresponding to the color of the ink to be used as the absorbance.

  A spectrophotometer, a photocoupler, a densitometer, or the like can be used as an example of an apparatus that can measure the light transmission amount of paper.

  An apparatus capable of measuring the light transmission amount of paper is installed on the transport mechanism, and it is desirable from the viewpoint of convenience to perform measurement immediately before printing and control the ink supply amount based on the measured information.

  When a device capable of measuring the amount of light transmitted through the paper is installed on the transport mechanism, the measuring instrument and light source are installed in a location that is not affected by external light in the printer, or the light source and measurement are placed across the transport mechanism. It is preferable that the apparatus is installed in a proximity state in which the distance between the vessels is about 1 to 5 mm.

  The control of the ink-jet ink supply amount is preferably performed based on the strike-through limit amount obtained from the relationship between the light transmission amount obtained in advance and the ink-jet ink supply amount.

  The strike-through limit amount is the maximum supply amount of ink that does not cause strike-through when the supply amount of inkjet ink is changed. By measuring the light transmission amount and the strike-through limit amount for various types of recording media in advance and calculating the correlation between them, the ink supply amount during recording can be controlled based on the strike-through limit amount.

  As a control method based on the strikethrough limit amount, a method of determining the maximum ink supply amount (maximum supply amount) based on the strikethrough limit amount is preferable. That is, a method of setting the maximum supply amount to be equal to or less than the strike-through limit amount is a preferable aspect.

  As the see-through limit amount, the amount of ink may be expressed by the volume per recording medium, or the ratio of the maximum supply amount that does not show through to the maximum ink supply amount of the recording apparatus (for example, recording The maximum value of the supply amount of the apparatus may be 1, and the maximum supply amount that does not show through to the maximum value may be expressed.

  The method for controlling the supply amount is not particularly specified, but it is simple to perform by controlling the discharge amount from the inkjet nozzle.

Specific examples of the discharge amount control method include a method of changing the droplet amount of one dot, a method of controlling the head temperature, a method of thinning out the number of ejections, and a method of reducing the total ink supply amount by color management. It is done.
Printing is performed so that the supply amount falls within the range obtained from the relationship between the light transmission amount and the supply amount that does not cause back-through.

  In the present invention, a light source capable of irradiating light that passes through the recording medium, a measuring instrument that measures the amount of light transmitted through the recording medium, and a value of the ink according to the measured value of the amount of transmitted light. A recording method using an ink jet printer characterized by having a means for controlling the maximum supply amount is a preferred embodiment.

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

  A solvent having a surface tension at 25 ° C. of 25 mN / m or more and 40 mN / m or less, a viscosity at 25 ° C. of 1 mPa · s or more and 50 mPa · s or less, and a vapor pressure at 25 ° C. of 133 Pa or less will be described. .

  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.

  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 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, 3-methyl-2,4-pentanediol, diethylene glycol monoethyl ether Or the like can be mentioned acetate.

  The ink used in the present invention may contain various functional additives in addition to the above-described solvents.

  The ink used in the present invention contains a colorant in the above-mentioned solvent, and further contains each additive as described below, as the hue of the colorant used in the present invention, for example, Yellow, 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 in which the colorant is a dye, or a pigment ink or a colorant that forms a dispersion containing fine pigment particles, in which the colorant is insoluble in the solvent constituting the inkjet ink. The present invention can be applied to various ink-jet inks such as a dispersion ink composed of a dispersion of a colored polymer.

  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 the 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.

  By using the above-mentioned ink, it is possible to perform printing with high surface dryness and good suitability for high-speed printing. Furthermore, although it is highly penetrable, only the solvent penetrates into the paper and the colorant remains on the surface. Therefore, it is considered that there is a high correlation between the paper permeability and the penetration. Further, as described in Japanese Patent Application No. 2005-220296, the print density itself is as high as that of water-based ink.

  In the inkjet ink used in 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 the ink droplets after ink ejection into the recording medium, 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.

  In the ink jet recording method of the present invention, for example, an ink jet print is obtained by ejecting ink as droplets from an ink jet head based on a digital signal and adhering to a recording medium by a printer loaded with ink jet ink.

  When performing the inkjet 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.

  Among them, in the ink jet recording method of the present invention, the ink of the present invention is ejected from a piezo ink jet recording head having a nozzle diameter of 30 μm or less, recording is performed on plain paper, and the nozzle diameter is 30 μm or less. It is desirable to perform recording on plain paper by discharging from a piezo-type ink jet recording head of the line head type. The printing characteristics of the ink of the present invention can be sufficiently extracted by printing on the shuttle head type recording head using a line head type recording head.

[Preparation of pigment dispersion A]
After mixing 15 parts by mass of carbon black (Mitsubishi Carbon Black MA100, manufactured by Mitsubishi Chemical Corporation) as a pigment, 15 parts by mass of Jonkrill 501 as a dispersion resin, 5 parts by mass of TPGME, and 65 parts by mass of water, the diameter is 0.5 mm. 200 parts by mass of zirconia beads were put into a polypropylene plastic bottle and sealed, and dispersed for 5 hours with a paint shaker to obtain a black pigment dispersion A.

[Preparation of ink]
It seemed to become the following combination to the plastic bottle containing the dispersion liquid, and a solvent and water were added and stirred for about 30 minutes with a paint shaker. The numerical value of the addition amount in the table represents parts by mass.

  Thereafter, the beads were removed, and filtration and membrane deaeration treatment using a hollow fiber membrane were performed to prepare an ink.

Tripropylene glycol monomethyl ether 230 parts by mass Water 45 parts by mass Pigment Dispersion A 100 parts by mass [Measurement of light transmission amount, calculation of limit amount for see-through]
Using the ink adjusted as described above and the paper shown in Table 1, the absorbance was measured for each paper, and the relationship between the back-through limit amount and the absorbance was determined by changing the ink supply amount. As the back-through limit amount, the density of the portion to which ink is supplied on the surface opposite to the surface to which ink has been supplied (back surface) is measured, and if the density is 0.08 or less, no back-through has occurred. The maximum value of the ink supply amount in a state where no omission occurred was used. As the ink supply amount, the ratio of the maximum supply amount when the back-through does not occur when the maximum supply amount of the used inkjet recording apparatus is set to 1 was used. The following equation was obtained as the relationship between the absorbance and the amount of limit for strikethrough.

Strikethrough limit amount = 2.11 × absorbance-5.90
Absorbance was measured using a spectrophotometer V550 (JASCO). A value of 550 nm was used as the absorbance. Table 1 shows the through-through limit amount (ratio) for each paper. Using the absorbance value obtained by measuring the absorbance, the printer was set so that the strikethrough limit amount = the maximum supply amount based on the strikethrough limit amount calculated according to the above formula. As the maximum supply amount, a ratio when the maximum discharge amount of the ink jet recording apparatus used in the same manner as described above was set to 1 was used. Using the maximum supply amount means that the maximum density of the image to be recorded is 1, and the density of the entire image is changed at a ratio that gives the maximum shot amount, and recording is performed based on the changed image data. Is to do.

  For example, for J paper, a value obtained by multiplying the image density value by 0.47 was used as the image density, and ink jet recording was performed based on this value.

[Print]
The ink prepared above was used in a Hewlett-Packard printer HP-PSC1610.

  Two print patterns were prepared by Photoshop 7.0, and image pattern A was printed only on the front side with 10cm x 10cm black 100% black image, 10cm x 10cm black 100% solid image on the front side, and 5 points on the back side. An image pattern B for printing the Mincho font was prepared.

  At the time of printing, printing was performed by controlling the maximum ink supply amount as described above based on the absorbance value of the paper.

  For each solid image of the pattern A for determining the amount of back-through, the surface density and the back surface density were measured 3 days after printing. Since the density of the back surface is greatly affected by the color of the paper itself, the value calibrated based on the density of the non-printed area of the paper was used in order to match the actual sense of see-through. . That is, the surface concentration and the back surface concentration were defined as follows.

Surface density: (Measurement value of density on the printed surface)
Back surface density: (Measurement value of density on the back side of the printed part)-(Measurement value of density on the non-printed part)
The measured value of the print density was Xwrite 938 (Japanese lithographic equipment), and the value of visual density in status A was used.

  The results are shown in Table 1.

  In any of the plain papers, the back surface density was 0.07 to 0.08, which could be suppressed to a level with no problem. Furthermore, even with CFPaver having the same thickness as J paper, it was possible to suppress the show-through without lowering the print density more than necessary.

  Furthermore, although visual evaluation was performed about the pattern B, there were no problems, such as becoming difficult to read a character.

Appropriate evaluation of high-speed printing For each paper in Table 1, immediately after printing pattern A, unprinted paper was pressed from above to check whether ink adhered.

  There was no ink adhesion on any of the papers.

  From the above, it can be seen that the recording method of the present invention is an ink jet recording method that does not show through regardless of the paper type, has a high print density, and high-speed printing characteristics.

It is the schematic which shows an example of the inkjet recording device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording medium 2 Light source 3 Light transmission amount measuring device 4 Inkjet head 5 Ink supply amount control means 6 Conveyance roller

Claims (4)

It contains 10 to 45% by mass of water, has a surface tension at 25 ° C. of 25 mN / m or more and 40 mN / m or less, a viscosity at 25 ° C. of 1 mPa · s to 50 mPa · s, and a vapor pressure at 25 ° C. An ink jet recording method for forming an image by supplying an ink jet ink containing 50 to 90% by mass of a solvent of 133 Pa or less to both sides of a recording medium, measuring the light transmission amount of the recording medium, and measuring the light An ink jet recording method, comprising: controlling an ink jet ink supply amount to the recording medium in accordance with a transmission amount. The inkjet recording method according to claim 1, wherein the control is performed based on a through-through limit amount obtained from a relationship between a light transmission amount obtained in advance and a supply amount of the inkjet ink. The ink jet recording method according to claim 2, wherein the control is performed by determining a maximum supply amount based on the back-through limit amount. 4. An ink jet recording apparatus for use in the ink jet recording method according to claim 3, wherein a light source capable of irradiating light transmitted through the recording medium and a light transmission amount of the transmitted light transmitted through the recording medium are measured. An ink jet recording apparatus comprising: a container; and means for controlling a maximum ink supply amount in accordance with a measured numerical value of the light transmission amount.