JP2007021925A - Inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method which enables a printing image with excellent water resistance, resistance to scuffing and feeling of gloss to be formed in an optical recording medium such as CD or DVD. <P>SOLUTION: This inkjet recording method is to make a colored ink containing a coloring material and a transparent ink not containing a coloring material adhere to a printable region for the optical recording medium with at least an optical recording layer formed on a light transmitting substrate, with the help of an inkjet recording process. The transparent ink contains not less than one kind of cationic substance selected from the group consisting of a cationic resin and a cationic surfactant. In addition, the transparent ink can contain a luminescent substance which has no absorptive wavelength in a visible light region and shows a luminescence in a visible light region under a specific light source. Thus the transparent ink is effective for forgery prevention in the recording medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording method for forming a printed image excellent in water resistance, abrasion resistance, and glossiness on an optical recording medium such as a CD or DVD on which information is recorded / reproduced using a laser beam.

  An optical recording medium is a means for storing various information such as audio data and image data in addition to computer information, and is a write-once type (CD-R) capable of recording and reproducing information, and can be erased after information is recorded. Rewriting type (CD-RW) has been developed and is widely used. In recent years, with the increase in the amount of information handled, DVD-R (recordable type) and DVD-RW (rewritable type), which are optical recording media having a larger capacity than CD-R and CD-RW, have begun to spread. . In these optical recording media, since a user records data after purchasing an optical recording medium containing no data, it is necessary to display the recorded contents on the surface of the optical recording medium after data recording.

  As a method of displaying characters and images on the surface of an optical recording medium, there are a method of handwriting directly on the surface using an oil pen or the like, a method of sticking a printable label on the surface, and the like. It cannot be used for applications, and there is a concern that label sticking may cause equipment failure due to label peeling. Therefore, a method has been put to practical use in which an ink receiving layer capable of printing is provided on the side opposite to the light incident surface of the optical recording medium, and characters and images are printed on the ink receiving layer using an inkjet printer or the like. Such optical recording media are commercially available as printable CD-R, printable DVD-R, and the like.

  As the printable optical recording medium, for example, a recording layer, a metal reflective layer, one layer or two or more protective layers are sequentially laminated on a transparent substrate, and the protective layer exposed on the surface is water-absorbing and / or An optical recording medium comprising a UV curable resin containing an oil-absorbing organic filler and / or an inorganic filler and configured to print the surface of the protective layer (see Patent Document 1), or a light-absorbing layer on a transparent substrate, An optical recording medium in which a light reflecting layer, a protective layer and / or a print receiving layer are sequentially laminated, and the outermost protective layer or print receiving layer contains a polyvinyl acetal resin, a water-dispersible resin and / or a water-soluble resin (patent) Reference 2).

  However, the conventional printable optical recording medium has poor water resistance and abrasion resistance of the printed image, and the printed image bleeds when exposed to water or exposed to moisture, or the printed image peels off due to slight friction. There was a problem. Further, it is difficult to say that the glossiness of the printed image is sufficient, and an improvement thereof has been desired.

JP 7-169100 A JP-A-8-161769

  Accordingly, an object of the present invention is to provide an ink jet recording method capable of forming a printed image excellent in water resistance, abrasion resistance and glossiness on an optical recording medium such as a CD or DVD.

  The present invention relates to an ink jet method in which a colored ink containing a color material and a transparent ink not containing a color material are attached to an area to be printed of an optical recording medium having at least an optical recording layer on a translucent substrate by an ink jet recording method. A recording method, wherein the transparent ink achieves the above object by providing an ink jet recording method containing at least one cationic substance selected from the group consisting of a cationic resin and a cationic surfactant. Is.

According to the inkjet recording method of the present invention, by using a transparent ink containing a specific cationic substance together with a commonly used colored ink, water resistance, abrasion resistance, and the like can be obtained on an optical recording medium such as a CD or DVD. A printed image having excellent gloss can be formed.
In addition, when inkjet recording is performed on an optical recording medium using the transparent ink containing “a luminescent substance that does not have an absorption wavelength in the visible light region and emits light in the visible light region under a specific light source”, Since the attached portion of the transparent ink in the optical recording medium emits light under a specific light source, it is easy to determine whether the optical recording medium is genuine or counterfeit, and is effective in preventing forgery of the optical recording medium. Is.

  In the ink jet recording method of the present invention, a colored ink containing a color material and a transparent ink not containing a color material are used. First, these inks will be described.

  The colored ink according to the present invention contains a coloring material, further contains water as a main solvent, and is prepared by adding a pigment dispersant, a surfactant, a water-soluble organic solvent, and the like as necessary.

  The coloring material used for the colored ink may be any material that can be used for an aqueous ink jet recording ink, and may be either a dye or a pigment, or both may be used in combination. The content of the color material is preferably 1 to 30% by weight, more preferably 3 to 10% by weight, based on the total weight of the ink, from the viewpoint of the balance between the print density and the ejection stability.

  Examples of the dye (coloring material) that can be used include acid dyes, basic dyes, direct dyes, food dyes, and reactive dyes. Specifically, for example, Acid Yellow 23, 25; Direct Yellow 12, 26, 86, 130; Basic Yellow 9, 11; Acid Red 27, 28, 52, 254, 289; Reactive Red 180; Direct Red 9, 13, 17, 23, 227; Basic Red 3; Acid Blue 8, 254; Basic Blue 9; Direct Blue 78, 86, 199; Acid Black 52, 172, 208; Food Black 2, Direct Black 19, 22, 28, 154: Process reactive black 31 etc. are mentioned.

  Examples of the pigment (coloring material) include azo pigments (for example, azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinones). Organic pigments such as pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, nitro pigments, nitroso pigments, aniline black; carbon blacks (eg furnace black, thermal lamp black, acetylene black, channels) Black, etc.), inorganic pigments such as metal oxides, metal sulfides and metal chlorides; extender pigments such as silica, calcium carbonate and talc. Specifically, for example, C.I. I. Pigment Yellow 74, 93, 109, 110, 128, 138, 150, 151, 154, 155, 180, 185; I. Pigment red 122, 202, 209; I. Pigment violet 19; C.I. I. Pigment blue 15: 3, 15: 4, 60; C.I. I. Pigment green 7 (phthalocyanine green), 10 (green gold), 36, 37; C.I. I. Pigment brown 3, 5, 25, 26; I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 34, 36, 38 and the like.

  In addition, when using a pigment as a coloring material, the dispersion stability of the pigment in an ink can be further improved by using a pigment dispersant together with a pigment. Examples of the pigment dispersant include polyvinyl alcohols; polyvinylpyrrolidones; polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, acrylic Acrylic resin such as acid-acrylic acid alkyl ester copolymer; styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-α-methylstyrene -Styrene-acrylic resins such as acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-alkyl acrylate copolymer; styrene-maleic acid copolymer; styrene-maleic anhydride copolymer; vinylnaphthalene -Acrylic acid copolymer; Phthalene-maleic acid copolymer; vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl-ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid Vinyl acetate copolymers such as copolymers, or salts thereof; proteins such as glue, gelatin, casein, and albumin; natural rubbers such as gum arabic and tragacanth; glucosides such as saponin; alginic acid and propylene alginate Examples include alginic acid derivatives such as glycol esters, triethanolamine alginate, and ammonium alginate; cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxycellulose. It can be used as a mixture of more than seeds.

  In addition, examples of the surfactant used in the colored ink include amphoteric surfactants and nonionic surfactants that can improve the permeability to a recording medium (optical recording medium). Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazolines. There are derivatives. Nonionic surfactants include acetylene glycol surfactants, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene Ethers such as oxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, Sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate Ester such as chromatography bets, and the like other fluorine alkyl esters, fluorine-containing surfactants such as perfluoroalkyl carboxylates. One of these surfactants may be used alone, or two or more thereof may be mixed and used. The content of the surfactant is preferably 0.1 to 5% by weight with respect to the total amount of the ink.

  Among the above surfactants, acetylene glycol surfactants are particularly preferable from the viewpoints of image quality and ejection stability, and examples thereof include 2,4,7,9-tetramethyl-5-decyne-4,7- Examples include diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexyne-3ol. Commercially available acetylene glycol surfactants include Surfinol 82, 104, 440, 465, 485, or TG (all available from Air Products and Chemicals. Inc.), Olphine STG, Olphine E1010 (trade name) ( As described above, Nissin Chemical Co., Ltd.) is preferably used. Silicone surfactants can also be preferably used in the present invention. Examples of commercially available silicone surfactants include BYK347 and 348 (manufactured by Big Chemie Japan).

  Further, as the water-soluble organic solvent used in the colored ink, those effective for improving the solubility and ejection stability of various components contained in the ink are preferable, and examples of such a water-soluble organic solvent include ethylene. Glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol 1,5-pentanediol, 1,6-hexanediol, glycerin, thiodiglycol, mesoerythritol, pentaerythritol, 2-pyrrolidone, ethanol, methanol, butanol, propanol, isopropano Alkyl alcohols having 1 to 4 carbon atoms such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl Ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether , Diethylene glycol mono-t-butyl ether 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono- Glycol ethers such as n-butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether , Formamide, acetamide, dimethyl sulfoxide, sorbit, sorbitan, acetin, diacetin, Triacetin, sulfolane and the like can be mentioned, and one of these can be used alone or two or more of them can be used in combination. The content of the water-soluble organic solvent is preferably 1 to 30% by weight with respect to the total amount of the ink.

  Examples of other components that can be contained in the colored ink according to the present invention include pH adjusters such as diethanolamine and triethanolamine, saccharides such as glucose (clogging preventive agent), antiseptics and fungicides, and viscosity adjusters. , Antifoaming agents, ultraviolet absorbers, antioxidants and the like.

  The colored ink according to the present invention preferably has a surface tension in the range of 20 to 45 mN / m and a pH of 6.5 to 10 from the viewpoint of good wettability to an optical recording medium and ejection stability. In addition, the viscosity at a liquid temperature of 20 ° C. is preferably in the range of 2 to 10 mPa, and the content of various components described above can be adjusted so as to satisfy such physical property values. preferable.

  On the other hand, the transparent ink according to the present invention contains one or more cationic substances selected from the group consisting of a cationic resin and a cationic surfactant, and water as a main solvent, which do not contain a color material, as essential components. Contains.

  Examples of the cationic resin include polyamine condensates, dicyandiamide compounds, diallyldimethylammonium chloride, acrylamide compounds, and the like. Commercially available cationic resins include, for example, Senka F series, Papiogen series, Unisense series (above, Senka Co., Ltd.), PAS series, PAA series, DANFIX series, POLYFLOC series (above, Nittobo), Sumi A laze resin series (above, manufactured by Sumika Chemtex), Hymo Lock series, Himax series (above, made by Hymo), Sunfix series (above, made by Sanyo Chemical), etc. are preferably used. A resin emulsion having a cationic resin as a dispersoid can also be used. Examples of the commercially available resin emulsion include the Superflex series (above, manufactured by Daiichi Kogyo Seiyaku), the Movinyl series (above, manufactured by Hoechst Synthesis), etc. Is mentioned.

  Examples of the cationic surfactant include monoalkyl ammonium chloride, dialkyl ammonium chloride, EO addition type ammonium chloride, dialkyl dimethyl ammonium chloride, distearyl dimethyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, stearyl trimethyl ammonium chloride, and benzaza chloride. Luconium and the like can be mentioned. As a commercially available cationic surfactant, for example, Adekamin series manufactured by Asahi Denka Kogyo is preferably used.

  The content of the cationic substance is preferably 0.1 to 5% by weight with respect to the total weight of the ink from the viewpoint of the balance between the effect obtained by using the transparent ink and the ejection stability.

  If necessary, the transparent ink according to the present invention may contain various components (excluding coloring materials) that can be contained in the above-described colored ink, for example, a surfactant, a water-soluble organic solvent, a pH adjuster, and the like. Can do.

  In addition, the transparent ink according to the present invention may contain “a luminescent substance that does not have an absorption wavelength in the visible light region and emits light in the visible light region under a specific light source”. This light-emitting substance is a substance that does not emit light under normal natural light or an illuminating lamp, or is invisible to light even when it emits light, but emits light that is visible under a specific light source such as ultraviolet rays. When ink jet recording is performed on an optical recording medium using a transparent ink containing such a luminescent substance, the adhering portion of the transparent ink emits light under a specific light source, so that the optical recording medium is genuine. It is easy to determine whether it is a counterfeit, and it is effective in preventing forgery of the optical recording medium. However, in order to obtain the anti-counterfeit effect by applying such transparent ink, it is assumed that the optical recording medium itself, which is an inkjet recording target, does not contain a luminescent substance.

  Examples of the light-emitting substance include a pyrene derivative, a coumarin derivative, an aminocoumarin derivative, a carpostyryl derivative, a dibenzooxazolyl derivative, and a thiazole derivative as a light-emitting substance (fluorescent brightener) that emits light in the visible light region under ultraviolet light. , Imidazole derivatives, benzimidazole derivatives, imidazoline derivatives, pyrazoline derivatives, benzidine derivatives, stilbene derivatives, distilbene derivatives, disulfonic acid derivatives, naphthalimide derivatives, distyrylbiphenyl derivatives, etc., one of these alone or two The above can be mixed and used. As commercially available luminescent substances, Kayaphor HBC and STC, which are fluorescent dyes manufactured by Nippon Kayaku, White Series, Nichion White series, Whitex series manufactured by Sumitomo Chemical, etc., which are fluorescent dyes manufactured by Nissei Kasei, are preferably used.

  The content of the luminescent substance is preferably 0.1 to 10% by weight with respect to the total weight of the ink from the viewpoint of light emission intensity and ink ejection stability.

  The surface tension, pH, and viscosity at a liquid temperature of 20 ° C. of the transparent ink according to the present invention are preferably in the same ranges as the above-described colored ink.

  In the ink jet recording method of the present invention, a desired image is printed by an ink jet recording method on a print area of an optical recording medium such as a CD or DVD using the above-described colored ink and transparent ink. In the practice of the present invention, a known optical recording medium compatible ink jet recording apparatus is preferably used. As a commercially available ink jet recording apparatus, for example, PM-870C, 950, 980, G800 manufactured by Seiko Epson is preferably used. There are various ink jet recording methods (recording head ejection methods), such as an electro-mechanical conversion method using a piezoelectric element such as a piezo element and an electro-thermal conversion method using an electro-thermal conversion element such as a heater. However, the present invention can be applied to any inkjet recording method.

  In the ink jet recording method of the present invention, either colored ink or transparent ink may be attached to the printing area first, or both inks may be attached simultaneously. In addition, when any one of the inks is attached first, the time from when one ink is attached until the other ink is attached is not particularly limited, but is preferably about several seconds.

  From the standpoint of maximizing the effect of the transparent ink, it is preferable that the transparent ink is attached at least to a colored ink attachment portion or a planned attachment portion in the printing area. As described above, after the colored ink is attached to the printing area, the transparent ink is attached to the attached portion (the transparent ink is attached to the attached portion of the colored ink), or the colored ink is attached to the portion to be attached in the future. Printed image by overlapping the colored ink dots and the transparent ink dots by attaching the transparent ink prior to the ink or simultaneously with the colored ink (by attaching the transparent ink to the portion where the colored ink is to be attached). It is possible to stably obtain good results with respect to water resistance, rubbing resistance and glossiness.

  The adhesion amount of the transparent ink in the printing area is preferably adjusted as appropriate according to the adhesion amount of the colored ink. As a method for controlling the adhesion (discharge) of transparent ink, for example, the amount of colored ink adhering per unit area is minimized, and the amount of adhering colored ink per unit area is minimized. Maximize the amount of transparent ink adhering to the lowest low-duty part (if there is a non-printing part where colored ink does not adhere to the printing area), the middle part between the high-duty part and the low-duty part A method is conceivable in which the amount of the transparent ink attached to the ink is appropriately changed according to the amount of the colored ink per unit area. It is preferable that the adhesion amount of the transparent ink to the intermediate portion is inversely proportional to the adhesion amount of the colored ink. According to this control method, components derived from both inks can be uniformly attached over the entire printing area, so that variation in glossiness can be effectively suppressed, and the optical recording medium The weight balance is maintained, and surface blurring and eccentricity do not occur during information recording / reproducing of the optical recording medium, and reading errors can be effectively prevented.

The amount of the transparent ink to be printed in the print area is preferably determined by the relative relationship with the colored ink as described above. However, in order to ensure that a predetermined effect is obtained, On the other hand, it is preferably 5 mg / inch ² or more in terms of solid content. However, since it becomes difficult to dry if the amount of transparent ink attached is too large, the upper limit of the amount of attached ink is preferably about 20 mg / inch ² .

  In the present invention, the colored ink and transparent ink adhesion (ejection) control is performed by creating a printer driver composed of a program code corresponding to such a control configuration, and connecting or incorporating the printer driver in an inkjet recording apparatus. This can be implemented by using an ink jet recording apparatus installed on a computer and thus installed with a printer driver.

Hereinafter, an optical recording medium to which the inkjet recording method of the present invention is applied will be described.
FIG. 1 is a schematic cross-sectional view of an example of an optical recording medium to which the present invention can be applied. The optical recording medium shown in FIG. 1 is a so-called CD-R type optical disc, and a tracking guide groove 1a is formed in a spiral shape on a donut-shaped disc-shaped translucent substrate 1 having a clamp hole in the center. The optical recording layer 2, the light reflecting layer 3, the protective layer 4 and the ink receiving layer 5 are sequentially laminated on the guide groove 1a, and information is obtained by irradiating laser light from the translucent substrate 1 side. It corresponds to the method of recording and playback of The ink receiving layer 5 is a layer on which ink jet recording is performed, and this surface serves as a printing area of the optical recording medium.

  The translucent substrate 1 is made of a plastic such as polycarbonate, polymethyl methacrylate, polystyrene resin, vinyl chloride resin, epoxy resin, or glass.

  The optical recording layer 2 is formed of a dye-containing thin film, an inorganic compound thin film made of a metal such as Te, a magneto-optical recording alloy thin film made of FeTbCo, a phase change recording alloy thin film such as GeSbTe, AgInSbTe, or SnSbSe.

  The light reflecting layer 3 is formed by vapor deposition, sputtering, ion plating, or the like of a metal or alloy material such as Au, Ag, Cu, Ni, or Pt.

  The protective layer 4 is a layer that physically and chemically protects the optical recording layer 2 and the light reflecting layer 3, and is formed of an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like.

  The ink receiving layer 5 is a layer configured to be capable of ink jet recording. Specifically, (1) a water-soluble resin layer containing 20% by weight or more, preferably 70 to 98% by weight of a water-soluble polymer, or ( 2) It consists of a porous pigment layer containing 30% by weight or more of pigment, preferably 50 to 85% by weight, and a binder.

  Examples of the water-soluble polymer (1) include gelatins, polyvinyl alcohols, polyvinyl pyrrolidones, cellulose derivatives, acrylic derivatives, and the like.

Silica, alumina or the like is used as the pigment (2). The primary particle diameter of the pigment is preferably 5 to 50 nm.
As the binder (2), polyvinyl alcohol and its modified products, styrene-butadiene copolymer, styrene-acrylic copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl acetate copolymer, etc. are used. It is done. The binder content is preferably 15 to 40% by weight with respect to the pigment in the ink receiving layer.

  In the ink receiving layers of the above (1) and (2), a cationizing agent, a hardening agent, a surfactant, a thickener, an antifoaming agent, an ultraviolet absorber, an antioxidant, an antiseptic are respectively provided as necessary. Various additives, such as an agent and a fungicide, are contained.

  Further, the ink receiving layer 5 may have a glossy surface with a high glossiness or a matte (matte) tone. According to the inkjet recording method of the present invention, not only when the surface of the printing area is glossy, but also when the surface of the printing area is matte, the matte printing area has a good gloss feeling. Can be granted. Normally, the matte surface has a 20-degree glossiness defined by JIS-Z8741 of 10% or less, and the glossy surface has a 20-degree glossiness of more than 10%.

  The ink jet recording method of the present invention is particularly effective for the optical recording medium (printable optical recording medium) having the ink receiving layer described above, but the application target of the present invention is limited to the optical recording medium having the configuration shown in FIG. The present invention is not applied to an optical recording medium having at least an optical recording layer on a translucent substrate, that is, an optical recording medium in which information is recorded / reproduced using laser light. Can do. Of course, the present invention is not limited to the CD-R type optical disc, the CD type read-only optical disc (CD-ROM), the rewritable CD-RW type optical disc, the DVD type read-only optical disc DVD-R, and the additional recording. The present invention can also be applied to possible optical disks such as DVD-RAM and -RW.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and test examples showing the effects of the present invention. However, the present invention is not limited to the examples.

  Transparent inks A and B having the following compositions were prepared.

<Composition of transparent ink A>
・ Cationic resin 3.0% by weight
(Smiles resin 1001, manufactured by Sumika Chemtex)
・ Glycerin 10.0% by weight
・ Surfactant (Olfin STG, manufactured by Nissin Chemical) 3.0% by weight
・ Ion exchange water balance

<Composition of transparent ink B>
・ Cationic resin 3.0% by weight
(Smiles resin 1001, manufactured by Sumika Chemtex)
・ Glycerin 10.0% by weight
・ Surfactant (Olfin STG, manufactured by Nissin Chemical) 3.0% by weight
・ Fluorescent dye (Kayaphor HBC, Nippon Kayaku) 3.0% by weight
・ Ion exchange water balance

[Examples 1-3]
In the color ink jet printer PM-980C manufactured by Seiko Epson, the dark yellow ink that is standardly installed in the printer is replaced with the transparent ink A, and six types of colored inks of cyan, magenta, yellow, light cyan, light magenta, and black are used. And an ink jet printer provided with one type of transparent ink. Then, using this inkjet printer, images are printed on the print areas of the following three types of inkjet printer compatible DVD-Rs (matte medium 1, matte medium 2, and glossy medium) to produce printed matter. did. Printing was performed by attaching the colored ink to the printing area and then attaching the transparent ink to the colored ink adhesion portion. The adhesion amount of the colored ink was 5 mg / inch ^{2 in} terms of solid content, and the adhesion amount of the transparent ink was 10 mg / inch ^{2 in} terms of solid content. The print image was a high-definition color digital standard image [(ISO / JIS-SCID), image name “portrait” (sample number 1, image evaluation recognition number N1)].
・ Matte tone medium 1: DVD-R47HCCPWC, manufactured by TDK ・ Matte tone medium 2: DR47WPC, manufactured by Hitachi Maxell ・ Glossy adjusted medium: DR47PH, manufactured by Hitachi Maxell

[Examples 4 to 6]
In Examples 1 to 3, an image was printed on each of the three types of DVD-R in the same manner as in Examples 1 to 3 except that the transparent ink B was used instead of the transparent ink A to prepare printed matter.

[Comparative Examples 1-3]
In Examples 1 to 3, an image was printed on each of the three types of DVD-R in the same manner as in Examples 1 to 3 except that no transparent ink was used, and printed matter was produced.

  The printed matter produced as described above was evaluated for water resistance, rubbing resistance and glossiness by the following methods. The evaluation results are shown in Table 1 below.

  Moreover, when the black surface which has a peak in 380 nm was irradiated with respect to the printing surface of the printed matter obtained in Examples 4-6 (Example using the transparent ink B containing fluorescent dye), it was contained in transparent ink. The light emission of the fluorescent dye that had been present could be easily confirmed visually (all of the three types of DVD-R originally did not contain the fluorescent dye). From this result, it was confirmed that the ink jet recording methods of Examples 4 to 6 were effective as a means for preventing forgery of the optical recording medium.

(Water resistance evaluation method)
The printed material is left for 24 hours in an environment at room temperature of 25 ° C. and a relative humidity of 50%. Then, a 0.3 cc water droplet is dropped on the printed characters and further left in the same environment for 24 hours, and then the printed characters are visually observed. The case where no ink bleeding was observed was designated as A (good water resistance), the characters were blurred but B was readable, and the characters were severely blurred and C were not readable.

(Rubbing resistance evaluation method)
After rubbing the printed surface of the printed material with the belly of the finger, the state is visually observed, and A (abrasion resistance is good) when the color material is not removed from the printed image, and some color material is confirmed to be detached. The material was designated as B, and the material with clear color material removal was designated as C.

(Glossy evaluation method)
The printed surface of the printed material is visually observed, and A (good gloss) is not inferior in gloss compared to the glossy surface of the silver salt photograph, and partially glossy compared to the glossy surface of the silver salt photograph. However, it was determined that B had a generally good gloss feeling, and C had an overall matte (matte) tone or gloss unevenness.

It is a cross-sectional schematic diagram of an example of an optical recording medium to which the inkjet recording method of the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Translucent substrate, 2 ... Optical recording layer, 3 ... Light reflection layer, 4 ... Protective layer, 5 ... Ink receiving layer

Claims (9)

This is an ink jet recording method in which a colored ink containing a color material and a transparent ink not containing a color material are adhered to an area to be printed of an optical recording medium having at least an optical recording layer on a translucent substrate by an ink jet recording method. And
The ink-jet recording method wherein the transparent ink contains one or more cationic substances selected from the group consisting of a cationic resin and a cationic surfactant.   The ink-jet recording method according to claim 1, wherein the transparent ink contains a light-emitting substance that does not have an absorption wavelength in the visible light region and emits light in the visible light region under a specific light source.   The inkjet recording method according to claim 1, wherein the transparent ink is attached to at least a portion to which the colored ink is attached or a portion to be attached in the printing region.   The transparent ink adheres to the high duty portion where the amount of the colored ink adhering per unit area is the largest, and the transparent ink adheres to the low duty portion where the adhering amount of the colored ink per unit area is the smallest. 4. The ink jet recording according to claim 3, wherein the adhesion amount is maximized, and the adhesion amount of the transparent ink to an intermediate portion between the high duty portion and the low duty portion is appropriately changed according to the adhesion amount per unit area of the colored ink. Method.   The inkjet recording method according to any one of claims 1 to 4, wherein the printing area is composed of a water-soluble resin layer containing 20% by weight or more of a water-soluble polymer.   The ink-jet recording method according to any one of claims 1 to 4, wherein the printing area comprises a porous pigment layer containing 30% by weight or more of a pigment and a binder.   The ink-jet recording method according to claim 1, wherein the printing area is formed of a mat-like ink receiving layer.   The ink-jet recording method according to claim 1, wherein the printing area is composed of an ink receiving layer having a glossy surface. A printed matter produced by the ink jet recording method according to claim 1.

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