JP2000225695A - Method for protecting print image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the protective properties of an image formed of an ink composition, above all, an image formed by an ink jet recording process. SOLUTION: A protecting layer is formed on a recording medium on which an image is formed by making a protecting solution for protecting the formed image adhere to the imaged recording medium by an ink jet recording process. The protecting layer protects the image against various physical or chemical changes, according to the contained components of the protecting solution. For example, the protecting solution containing an ultraviolet absorbing agent imparts light resistance and the protecting solution containing a resin having a skin forming power imparts the resistance to abrasion, water, ozone and humidity and at the same time, makes the image lustrous.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method, and more particularly to a method for enhancing the protection of a printed image using the ink jet recording method.

2. Description of the Related Art In order to obtain high-quality prints or images with an ink composition, efforts are mainly made from two aspects: improvement of the ink composition and improvement of the recording medium. The resulting image has no image bleeding, excellent image quality such as excellent color reproducibility, and maintains the formed high quality image for a long period of time, that is, deterioration due to sunlight and the like, and furthermore, ozone and the like in the air. It is required to have resistance to deterioration due to substances. Further, it is required that the image has physical strength, that is, the image quality is not impaired by rubbing or the like.

[0003] An ink jet recording method, which is one of the printing methods using an ink composition, is a printing method in which droplets of the ink composition are made to fly and adhere to a recording medium such as paper to perform printing. This method has a feature that high-resolution and high-quality images can be printed at a high speed with a relatively inexpensive device.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for enhancing the protection of an image formed by an ink composition, particularly an image formed by an ink jet recording method.

According to the first aspect of the present invention, the method includes a step of discharging and attaching a droplet of a protective liquid for protecting the formed image to a recording medium on which the image is formed. .

According to a second aspect of the present invention, an image is printed by ejecting droplets of an ink composition, attaching the droplets to a recording medium, and then protecting the formed image. And ejecting the droplets of the protective liquid onto the recording medium on which the image is formed.

According to the method of the present invention, a protective layer of a protective liquid is further formed on the image on the recording medium. This protective layer protects the image from various physical or chemical changes, depending on the components of the protective solution. For example, a protective solution containing an ultraviolet absorber imparts light resistance, and a protective solution containing a resin having a film forming ability imparts abrasion resistance, water resistance, ozone resistance, and moisture resistance, and at the same time, imparts gloss to an image. Can be.

[0008]

DETAILED DESCRIPTION OF THE INVENTION Ink jet recording method The ink jet recording method used in the method according to the present invention is a non-impact printing method in which ink droplets are generated in response to a digital signal or the like generated by a computer. Specifically, a piezoelectric drop-on-demand method using a piezoelectric thin film, a thermal method using the expansion force of bubbles generated by heating, and the like can be cited. In the present invention, any of them can be used, but in consideration of the influence of heating on the physical properties of the liquid to be discharged, the use of the piezoelectric drop-on-demand method is preferable.

In the method according to the present invention, a protective liquid described below is applied to a recording medium on which an image has been already formed, by an ink jet recording method. The adhesion of the protective liquid may be performed only on the portion of the image formed on the recording medium,
Further, it may be performed on the entire surface of the recording medium. From the viewpoint of the amount of consumption of the protective liquid, an embodiment in which the protective liquid is attached only to a portion where an image is formed is preferable. Further, according to the ink jet recording method, such control can be easily performed. Therefore, it can be said that this embodiment can further enjoy the advantages of the method according to the present invention.

The method of forming an image on a recording medium is not particularly limited, but is preferably formed by an ink jet recording method. That is, by adding a recording head for a protective liquid to an ink jet recording printer, an ink jet recording apparatus capable of performing the method according to the present invention relatively easily can be configured.

[0011] discharging the protection liquid by the inkjet recording method in the protection liquid present invention. The protective liquid is a liquid having a property of protecting an image formed on a recording medium. In the present invention, protection means, for example, protecting an image from various physical or chemical changes. Therefore, a substance having a property of protecting an image from various physical or chemical changes can be used as a component of the protective solution in the present invention.
Specifically, according to a preferred embodiment of the present invention, first, a protective liquid containing an ultraviolet absorbent is exemplified.
A protective solution containing an ultraviolet absorber imparts light fastness to an image.
Further, according to another aspect of the present invention, a protective liquid containing a resin having a film forming ability can be mentioned. A protective solution containing a resin having a film-forming ability can impart abrasion resistance, water resistance, ozone resistance, and moisture resistance, and can also impart gloss to an image. Further, according to another aspect, as the protective liquid,
Examples include antioxidants, light stabilizers, and radical absorbers.

The ultraviolet absorber usable in the present invention includes salicylic acid ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, and others. Specific examples include the following.

Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate (Seesorb 201 Nisseki calcium) and pt-butylphenyl salicylate (Sumisorb 90 Sumitomo Chemical, Viosorb 90 joint drug).

As a benzophenone-based ultraviolet absorber, 2,4-dihydroxybenzophenone (Viosorb 10) is used.
0 joint drug), 2-hydroxy-4-methoxybenzophenone (Uvinul M-40 BASF), 2-hydroxy-4-
Octoxybenzophenone (Viosorb 130 joint drug),
2,2'-dihydroxy-4-4'-dimethoxybenzophenone (Uvinul 3049 BASF), 2,2'-dihydroxy-4-methoxybenzophenone (Cyasorb UV-24 ACC)
2-hydroxy-4-methoxy-5-sulfobenzophenone (Uvinul MS40 BASF), 2,2'-dihydroxy-
4-4'-dimethoxy-5-sulfobenzophenone Na
Salt (Uvinul DS49 BASF).

Further, as the benzotriazole ultraviolet absorber, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole (JF-77 Johoku Chemical Co., Ltd.),
2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole (Tinuvin 320 Ciba-Geigy), 2- (2'-hydroxy-3'-t-butyl-
5'-methylphenyl) -5-chlorobenzotriazole (Tinuvin 326 Ciba-Geigy) and 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole (Tinuvin 328 Ciba-Geigy).

As the cyanoacrylate-based ultraviolet absorber, 2-ethylhexyl-2-cyano-3,3 '
-Diphenyl acrylate (Uvinul 3039 BASF) and ethyl-2-cyano-3,3'-diphenyl acrylate (Uvinul 3035 BASF).

Further, as other ultraviolet absorbers, 4
-Bis (polyethoxy) p-aminobenzoic acid polyethoxyethyl ester (Uvinul P25 BASF) and high molecular type 2- (2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole (RUVA-39 Otsuka Chemical), emulsion type polymer UVA-383 MA (BASF)
And the like.

Many of the above-mentioned ultraviolet absorbers are oil-soluble, and when these ultraviolet absorbers are added to an aqueous ink composition, the amount of the ultraviolet absorber is limited, and a sufficient effect may not be obtained. there were. In the present invention, when the composition of the protective liquid is an emulsion, the amount of the ultraviolet absorber added can be increased, so that a sufficient light-fast image can be provided.

It is also possible to use an inorganic ultraviolet absorber as the ultraviolet absorber, and examples thereof include titanium oxide (TiO ₂ ), zinc oxide (ZnO ₂ ) and cerium oxide (CeO ₂ ).

The resin having a film-forming ability which can be used in the present invention means a resin capable of forming a resin film on a printed image after adhering on the printed image on a recording medium. The resin layer on which the print was formed is abrasion resistant to the image,
Provides water resistance, ozone resistance and moisture resistance. Further, such a resin film can give gloss to an image and add value to the image.

A specific example of the resin usable in the present invention is a thermoplastic resin, which forms a film having strong water resistance and abrasion resistance when heated and cooled to a temperature higher than its softening or melting temperature. To do. According to a preferred embodiment of the present invention, as such a resin,
Those which are in the form of a resin emulsion and can form a resin film having water resistance and abrasion resistance by drying or heating, more preferably those having a minimum film formation temperature (MFT) of room temperature or less.

Specific examples of the thermoplastic resin include polyacrylic acid, polymethacrylic acid, polymethacrylate, polyethylacrylic acid, styrene-butadiene copolymer, polybutadiene, acrylonitrile-butadiene copolymer, and chloroprene copolymer. Polymer, fluororesin, vinylidene fluoride, polyolefin resin, cellulose, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, polystyrene, styrene-acrylamide copolymer, polyisobutyl acrylate, polyacrylonitrile, polyacetic acid Vinyl, polyvinyl acetal, polyamide, rosin resin, polyethylene, polycarbonate, vinylidene chloride resin, cellulose resin, vinyl acetate resin, ethylene-vinyl acetate copolymer, vinyl acetate-
Examples include, but are not limited to, acrylic copolymers, vinyl chloride resins, polyurethanes, rosin esters, and the like. Specific examples of the low molecular weight thermoplastic resin include polyethylene wax, montan wax, alcohol wax, synthetic oxidized wax, α-olefin-maleic anhydride copolymer, animal and plant waxes such as carnauba wax, lanolin, paraffin wax, Microcrystalline wax and the like.

The resin emulsion usable in the present invention means an emulsion in which the continuous phase is water and the dispersed phase is the following resin component. As the resin component of the dispersed phase, acrylic resin, vinyl acetate resin, styrene-butadiene resin, vinyl chloride resin, acryl-styrene resin, butadiene resin, styrene resin, crosslinked acrylic resin, crosslinked styrene resin, Benzoguanamine resin, phenol resin, silicone resin, epoxy resin and the like can be mentioned.

According to a preferred embodiment of the present invention, the resin is preferably a polymer having both a hydrophilic part and a hydrophobic part. Further, the particle size of these resin components is not particularly limited as long as an emulsion is formed.
Or less, more preferably about 5 to 100 nm.

These resin emulsions can be obtained by dispersion polymerization of a resin monomer in water together with a surfactant, if necessary. For example, an emulsion of an acrylic resin or a styrene-acrylic resin can be obtained by dispersing and polymerizing a (meth) acrylate or a (meth) acrylate and styrene together with a surfactant in water.
The mixing ratio of the resin component and the surfactant is usually 10: 1.
It is preferable to set it to about 5: 1. When the amount of the surfactant used is in the above range, better water resistance and permeability of the ink can be obtained. Although the surfactant is not particularly limited, preferred examples thereof include anionic surfactants (for example, sodium dodecylbenzenesulfonate, sodium laurate, ammonium salts of polyoxyethylene alkyl ether sulfate, and the like), nonionic surfactants ( For example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, etc.) can be used alone or in combination. A mixture of more than one species can be used. Also, acetylene glycol (Olefin Y and Surfynol 82, 104, 440, 465, 4
85 and TG (Air Products and Chemica
ls Inc.)) can also be used.

The proportion of the resin and water as the disperse phase component is in the range of 60 to 400 parts by weight of water, preferably 100 to 200 parts by weight, based on 100 parts by weight of the resin.

As such a resin emulsion, known resin emulsions can be used. For example, JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, and JP-A-3-160068. The resin emulsion described in JP-A-4-18462 can be used as it is.

It is also possible to use a commercially available resin emulsion, for example, Microgel E-100.
2, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001
(Acrylic resin emulsion, manufactured by Dainippon Ink and Chemicals, Inc.) Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink and Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, ZEON Corporation) Made), Cybinol S
K-200 (acrylic resin emulsion, manufactured by Seiden Chemical Co., Ltd.) and the like.

The radical absorber that can be used in the present invention is not particularly limited as long as it quenches the generated radical. For example, a hindered amine compound is a preferred example.

The hindered amine compound is, for example, a compound having at least one hindered amine represented by the following formula in a molecule.

Embedded image [Wherein, R ¹ , R ² , R ³ , and R ⁴ independently represent a lower alkyl group, a carbonyl group, and the like, and are preferably a methyl group or an ethyl group. R5 is a hydrogen atom, C _1-5
Represents an alkyl group, a pendyl group, an allyl group, an acetyl group and the like, and is preferably a hydrogen atom or a methyl group. A
Represents a polymer, or A represents when n = 1,
_{-NH 2, -OH, = CH 2} , = O, -R, -OR, -O
_{CO-R, -NHC 3 H 6} OCH 3, -NHCSSH ( wherein R is an alkyl group, -CH = CH2,

Embedded image Represents n), and when n = 2,

Embedded image (M is _{1~14), -NH (CH 2)} 3 NH-,

Embedded image Or -NHCSS-M-CNH- (where M is 2
Valence metal atom)

Another example of a hindered amine compound is a compound represented by the following formula. Wherein R ⁶ , R ⁷ , R ⁸ , and R ⁹ are each

Embedded image (Where R 'represents -H or -CH3). ]

As another example of a hindered amine compound, a compound represented by the following formula is exemplified.

Embedded image

Specific examples of the hindered amine compound include 4-verzoyloxy-2,2,6,6-tetramertipiperidine, bis- (2,2,6,6-tetramethyl-4-piperidyl). Malonate, bis- (2,2,
6,6-tetramethyl-4-piperidyl) phthalate,
2,2,6,6-tetramethyl-4-piperidylbenzoate, 4-amino-2,2,6,6-tetramethyl-
Piperidine, 2,2,6,6-tetramethyl-4-piperidyl) separate, bis- (2,2,6,6-tetramethyl-4-methylpiperidyl) separate, di- (1,
2,2,6,6-pentamethyl-4-piperidyl) -2
-N-butyl-2- (3,5-di-tbutyl-4-hydroxybenzyl) malonate, bis- (2,2,6,6
-Tetramethyl-4-carbonyloxypiperidino)-
p-dimethylbenzyl, 2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxo-disbiro [5.1.9.19] henecon, pis- (2,
2,6,6-tetramethyl-4-piperidinyl) separate, dimethylsuccinate, 2- (4-hydroxy-
2,2,6,6-tetramethyl-1-piperidinyl) ethynol condensate, [(6- (1,1,3,3-tetramethylbutyl) imino] -1,3,5-triazine-2,
4-diyl- (4- (2,2,6,6-tetramethylpiperidinyl) imino) -hexamethylene- (4- (2,
2,6,6-tetramethylpiperidinyl) imino)].

Among them, bis- (2,2,6,6-tetramethyl-4-piperidyl) malonate, bis-
(2,2,6,6-tetramethyl-4-piperidinyl)
Separate, bis- (2,2,6,6-tetramethyl-
4-piperidyl) phthalate, 2,2,6,6-tetramethyl-4-piperidylbenzoate, 4-amino-
2,2,6,6-tetramethyl-piperidine, 2,2
6,6-Tetramethyl-4-piperidinol is preferred.

In the present invention, the composition of the protective solution may be appropriately determined in consideration of the following. That is, the protective liquid is
It can sufficiently dissolve or disperse the components to be added thereto, and must not damage the ink jet recording head, the ink flow path in the printer, the ink tank, and further damage the image formed on the recording medium. Not desirable. Specifically, it may be formed by dissolving or dispersing additional components in a solvent system obtained by mixing water or an organic solvent (eg, alcohol) alone or in combination.

The ink jet recording apparatus for implementing the method according to the ink jet recording apparatus The present invention connexion hereinafter be described with reference to the drawings.

The ink jet recording apparatus shown in FIG. 1 is a mode in which ink and protective liquid are stored in a tank, and the ink and protective liquid are supplied to a recording head via an ink tube. That is, the recording head 1 and the ink tank 2 are connected by the ink tube 3. Here, ink tank 2
Is partitioned, and is provided with a chamber for ink and, in some cases, a plurality of color inks, and a chamber for protective liquid.

The recording head 1 moves along the carriage 4
It is moved by a timing belt 6 driven by a motor 5. On the other hand, the paper 7 as a recording medium is placed at a position facing the recording head 1 by the platen 8 and the guide 9. In this embodiment, a cap 10 is provided. A suction pump 11 is connected to the cap 10 to perform a so-called cleaning operation. The sucked ink is stored in a waste ink tank 13 via a tube 12.

FIG. 2 is an enlarged view of the nozzle surface of the recording head 1. The portion indicated by 1b is the nozzle surface of the protective liquid, and the nozzle 21 for discharging the protective liquid is provided in the vertical direction. On the other hand, the portion indicated by 1c is the nozzle surface of the ink, and the nozzles 22, 23, 24, and 25 eject yellow ink, magenta ink, cyan ink, and black ink, respectively.

Further, an ink jet recording method using the recording head shown in FIG. 2 will be described with reference to FIG. The recording head 1 moves in the direction of arrow A. During that move,
The ink composition is ejected from the nozzle surface 1c, and the recording medium 7
An image area 31 is formed thereon. Next, the recording medium 7 is transported by a predetermined amount in the paper feed direction arrow B. During that time, the recording head 1 moves in the direction opposite to the arrow A in the figure, and returns to the position on the left end of the recording medium 7. Then, a protective liquid is applied to the image area 31 on which an image has already been formed to form a protected area 32.

Further, as shown in FIG. 4, in the recording head 1, all the nozzles can be arranged in the horizontal direction. In the drawing, 41a and 41b are discharge nozzles of the protective liquid, from which yellow ink, magenta ink, cyan ink and black ink are respectively discharged from the nozzles 42, 43, 44 and 45. In the recording head of such an aspect, the recording head 1 can perform printing both in the forward path and the return path in which the recording head 1 reciprocates on the carriage, so that the recording head 1 has a higher speed than the case of using the recording head shown in FIG. Printing can be expected.

Further, in some ink jet recording apparatuses, replenishment of ink is performed by replacing a cartridge which is an ink tank. This ink tank may be integrated with the recording head.

FIG. 5 shows a preferred example of an ink jet recording apparatus using such an ink tank. In the figure, the same members as those of the apparatus of FIG. 1 are denoted by the same reference numerals. In the embodiment of FIG. 5, the recording heads 1a and 1b
Are integrated with the ink tanks 2a and 2b.
It is assumed that the recording head 1a or 1b discharges ink and protective liquid, respectively. The printing method may be basically the same as that of the apparatus shown in FIG. In this embodiment, the recording head 1a, the ink tank 2a, and the recording head 1a
The ink tank 2b moves on the carriage 4 together.

FIG. 6 shows a preferred example of an ink jet recording apparatus provided with a heater for heating a printed recording medium. FIG. 6 is similar to that shown in FIG. 1 except that a heater 14 is provided. The heater 14 may be a heater that contacts a recording medium and heats the recording medium, or may be a heater that irradiates infrared rays or the like or blows hot air without contacting the recording medium. When the protection liquid contains a resin, the heating of the heater 14 can effectively promote the formation of a film of the resin.

[Brief description of the drawings]

FIG. 1 is a view showing an ink jet recording apparatus preferably used for carrying out an ink jet recording method according to the present invention. In this embodiment, a recording head and an ink tank are respectively independent, and an ink composition and a protective liquid are ink. It is supplied to the recording head by a tube.

FIG. 2 is an enlarged view of a nozzle surface of a recording head,
Is the nozzle surface of the protective liquid, and 1c is the nozzle surface of the ink composition.

FIG. 3 is a diagram illustrating an ink jet recording method using the recording head of FIG. In the figure, 31 is an image area, and 32 is a protected area where a protective liquid has adhered on the image.

FIG. 4 is a diagram showing another embodiment of a recording head preferably used for carrying out the ink jet recording method according to the present invention, in which all ejection nozzles are arranged in a horizontal direction.

FIG. 5 is a view showing an ink jet recording apparatus preferably used for carrying out the ink jet recording method according to the present invention. In this embodiment, a recording head and an ink tank are integrated.

FIG. 6 is a view showing an ink jet recording apparatus preferably used for carrying out the ink jet recording method according to the present invention. In this embodiment, a heater for heating a recording medium after printing is provided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Ink tank 3 Ink tube 14 Heater 21 Protective liquid discharge nozzle 22, 23, 24, 25 Ink composition discharge nozzle 31 Protective liquid adhesion area 32 Print area

Claims (10)

[Claims] 1. An ink jet recording method comprising the step of ejecting and attaching droplets of a protective liquid for protecting a formed image on a recording medium on which the image is formed. 2. The method according to claim 1, further comprising the steps of: ejecting a droplet of the ink composition; adhering the droplet to a recording medium to print an image; and ejecting a droplet of a protective liquid for protecting the formed image. An ink jet recording method, comprising attaching to a recording medium on which an image is formed. 3. The ink jet recording method according to claim 1, wherein the protective liquid contains an ultraviolet absorbent. 4. The ink jet recording method according to claim 1, wherein the protective liquid comprises a resin having a film forming ability. 5. The ink jet recording method according to claim 4, wherein said resin is in the form of a resin emulsion. 6. The method according to claim 1, wherein the protective liquid comprises an antioxidant, a light stabilizer,
The ink jet recording method according to claim 1, further comprising a radical absorber. 7. The ink jet recording method according to claim 1, wherein said protective liquid is applied only on an image formed on a recording medium. 8. The recording medium according to claim 8, wherein the protective liquid is adhered to the entire surface of the recording medium.
The inkjet recording method according to claim 1. 9. An ink jet recording apparatus for performing the method according to claim 1. 10. The ink jet recording apparatus according to claim 9, further comprising a recording head for discharging a protective liquid.