JPS6226319B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to inkjet printing methods. Furthermore, the present invention relates to an inkjet printing method suitable for forming multicolor recorded images. More specifically, the present invention relates to an inkjet printing method suitable for forming multicolor recorded images with excellent color reproducibility and light resistance. The inkjet printing method is noiseless, enables high-speed recording, and can record on plain paper, so it has been adopted in terminal printers and has become rapidly popular in recent years. Furthermore, multicolor recorded image formation using a large number of ink nozzles has become popular as color plotters and color facsimiles. However, when performing multicolor recording, various problems occur that are not seen in monochrome recording. Unlike monochrome recording, the purpose of multicolor recording is usually to
It involves the formation of reproduction images such as photographs, posters, illustrations, and color drawings, and includes the following problems. (1) Original photographs, paintings, posters, illustrations,
Reproduction images must be created that faithfully reproduce the shape, color, and sharpness of color drawings, etc. (2) Original photographs, paintings, posters, illustrations,
Duplicate image areas and non-print areas that faithfully reproduce color drawings and the like are exposed to ultraviolet light for a long period of time and become contaminated. (3) Original photographs, paintings, posters, illustrations,
It is necessary to be able to quickly and stably produce reproduction images such as color drawings. (4) When inkjet printing, ink flows or scatters, contaminating non-printing areas. (5) During handling after printing, the image area is disturbed by being rubbed by some means, and the non-printing area is contaminated. Several proposals have been made in the past to solve such problems. For example, Unexamined Japanese Patent Publication No. 1973-
No. 89811 describes an inkjet printing method using yellow, magenta, and cyan inks that have limited reflection density curves on the media in order to achieve the color reproduction necessary to form a reproduction image that faithfully reproduces the original. Disclosed. Japanese Patent Application Laid-Open No. 49-89534 discloses a printing method using yellow, magenta, and cyan inks in order to faithfully reproduce an original image at high speed and stably. JP-A No. 52-53012 discloses that in order to obtain images with good density, resolution, and color reproducibility, the recording paper used has a method that reduces the horizontal spread of colored components in the ink.
In order to reduce the penetration of the coloring components in the ink in the thickness direction and to make the coloring components exist as much as possible on the surface of the paper layer, the paint is applied to a low-size base paper and the paint penetrates into the inside of the paper layer. An inkjet recording paper is disclosed. Furthermore, for the same purpose, JP-A No. 53-49113 discloses an inkjet recording paper in which paper to which fine powder of urea-formalin resin is added is impregnated with a water-soluble polymer; The issue is disclosed inkjetto recorded with a specific ventilation degree and ink absorption time. In addition, in order to ensure that reproduced images obtained by inkjet printing can be stored for a long period of time without fading, JP-A-54-68303 and JP-A-54-85804 use ink containing a water-soluble ultraviolet absorber. Disclosed. However, the multicolor recorded images formed using these techniques cannot fully satisfy the characteristics of color reproducibility and light fastness, and are unsatisfactory as an inkjet printing method. An object of the present invention is to provide an inkjet printing method suitable for forming multicolor recorded images with high color density, excellent resolution, and good color reproducibility. Another object of the present invention is to provide an inkjet printing method suitable for forming multicolor recorded images with excellent light fastness and suitable for long-term storage. Still another object of the present invention is to provide an inkjet printing method using a recording sheet having a coating layer containing yellow, magenta, cyan, and black inks having excellent light resistance and excellent color reproducibility and a dye image fading inhibitor. It is to provide. As a result of various studies, the present inventors have discovered that in the image forming method of inkjet printing, a water-based ink containing a highly light-fast water-soluble dye or a water-soluble direct dye as a coloring component is used, and a pigment containing a dye image fading inhibitor is used. It has been found that by inkjet printing on a recording sheet having a coating layer, it is possible to form a multicolor recorded image that has high color density, excellent resolution, excellent color reproducibility, and also has a high degree of light resistance. As a result of various studies, the present inventors have found that in the image forming method of inkjet printing, an ink containing a highly light-fast water-soluble dye or a water-soluble direct dye as a coloring component is used, and a dye selected from the phenolic anti-fading agents described below is used. It has been found that an image having extremely high light resistance can be formed by inkjet printing on a recording sheet containing an image fading inhibitor. According to the present invention, inks suitable for forming multicolor recorded images are yellow, magenta, cyan, and black, which have a high degree of light fastness, absorb in the desired spectral range, and have as little side absorption as possible. The dyes used are water-soluble acidic or water-soluble direct dyes. Among these dyes, preferred are those represented by the following general formula. For example, a yellow dye is a dye represented by the general formula (). General formula [] In the formula, R ₁ is a phenyl group, a substituted phenyl group (as a substituent, Cl, an alkyl group, an alkoxy group, a sulfo group, or a carboxyl group), an alkyl group, or a substituted alkyl group (as a substituent, a sulfo group or a cyanoethyl group) ), R ₂ is an alkyl group, phenyl group, substituted phenyl group (substituents include Cl, alkyl, alkoxy), cyano group, hydroxy group, alkoxy group,
Amino group, acylamino group, anilino group, ureido group, alkoxycarbonyl group, or carbamoyl group, X is a halogen atom, alkyl group, or alkoxy group, n is 1, 2, 3, 4, or 5, m is 1, 2 , or 3. When m is 1, R ₁ is preferably a sulfo-substituted alkyl group or a phenyl group. Next, some examples of water-soluble dyes contained in the ink of the present invention will be listed. However, the dye of the present invention is not limited thereto. Yellow dye example: As magenta dye, the following general formula (),
Dyes represented by ( ) or ( ) are preferred. General formula [] In the formula, R ₁ is a cyano group, an alkylsulfonyl group, an arylsulfonyl group, a trifluoromethyl group, or a trichloromethyl group. R ₂ is an amino group, an acylamino group, a substituted ureido group, an alkylamino group, an alkoxy group, a substituted alkoxy group, or Acyloxy group R ₃ is a hydrogen atom or an alkyl group; n represents 1 or 2; Next, some examples of water-soluble dyes contained in the ink of the present invention will be listed. However, the dye of the present invention is not limited thereto. Magenta dye example: Regarding the method for synthesizing the magenta dye of the present invention,
For example, the descriptions in JP-A-49-89534 and JP-A-54-8630 can be referred to. General formula [] In the formula, R ₁ and R ₂ are the same or different hydrogen atoms, halogen atoms (e.g., chlorine atom, bromine atom, etc.), lower alkyl groups (e.g., methyl group, ethyl group, etc.), lower alkoxy groups (e.g., methoxy group, ethoxy group, etc.), amino group, substituted amino group {For example, substituents include acyl group, (e.g. acetyl group, benzoyl group, methylsulfonyl group, etc.), lower alkyl group (e.g. methyl group, ethyl group, etc.), aryl group ( For example, phenyl group)
represents. p is an integer from 1 to 3, q is an integer from 1 to 4, (p+q)
represents 3, 4, 5 or 6. M represents Cu or Ni. general formula In the formula, R ₃ represents a hydrogen atom, a halogen atom (eg, chlorine atom, bromine atom, etc.), a lower alkyl group (eg, methyl group, ethyl group, etc.), or a lower alkoxy group (eg, methoxy group, ethoxy group, etc.). x is an integer from 1 to 3, y is an integer from 1 to 4, (x+y)
represents 4, 5 or 6. M represents Cu or Ni. Among the dyes represented by the general formula () or (), preferred ones are listed below. However, the dye of the present invention is not limited thereto. As the cyan dye, the following copper phthalocyanine tetrasulfonic acid or copper phthalocyanine disulfonic acid is preferable. The production of copper-phthalocyanine tetrasulfonic acid of the present invention is disclosed in U.S. Pat.
No. 3082201,
It can be easily synthesized by converting copper-phthalocyanine into copper-phthalocyanine tetrasulfonic acid chloride with chlorosulfonic acid and injecting it into water. [Sulfo groups contained in the dyes represented by the general formulas (), (), (), (), and copper phthalocyanine sulfonic acids are alkali metal salts (e.g., sodium salts, potassium salts, etc.), organic amines (e.g., triethylamines, pyridine salt, triethanolamine salt, ammonium salt, etc.). ] CI acid black 155 as a black dye
is suitable. According to the present invention, in order to form a multicolor recorded image with high color density and excellent color reproducibility, the dye is appropriately dispersed on the recording medium and absorbed in a desired spectral range, and as much as possible on the side. Ink that reduces absorption and can be jetted stably and continuously from the nozzle of an inkjet recording device, and for recording with good ink absorption and less lateral spread of ink colored components and less penetration in the thickness direction. Requires combination with seat. An ink that satisfies these properties preferably contains a wetting agent.
Preferred wetting agents have the following general formulas () to
Compounds represented by () can be mentioned. General formula () In the formula, R represents a hydroxyalkyl group or an alkoxyalkyl group. General formula () In the formula, R ₁ represents a hydrogen atom, an alkyl group, or a substituted alkyl group, and R ₂ , R ₃ , and R ₄ may be the same or different and represent a hydrogen atom, an alkyl group, a hydroxy group, or an alkoxy group. General formula () In the formula, R represents an alkyl group or a substituted alkyl group,
X represents an oxygen or sulfur atom. Preferred specific examples of the compounds represented by formulas () to () are listed below. According to the present invention, a recording sheet suitable for forming a multicolor recorded image with excellent light fastness adsorbs the dye in the ink and further prevents the dye image from fading due to ultraviolet rays or oxygen. This is a recording sheet in which a pigment coating layer coated with or containing an inhibitor is provided on the surface of a support. The dye image fading inhibitor is coated on the top of the pigment coating layer provided on the surface of the support, ie, on the side to be inkjet printed, or is coated on the pigment coating layer together with the pigment. According to the present invention, the phenolic anti-fading agent as a dye image anti-fading agent significantly improves the light fastness of an inkjet multicolor recorded image. Compounds that serve as phenolic anti-fading agents include phenol derivatives in which at least one of the ortho positions of the hydroxyl group is substituted with tertiary alkyl, bisphenol derivatives, and compounds containing a phenol derivative as part of a phosphoric acid ester; There are phenol derivatives in which the para position is substituted with an oxygen atom, and a 5- or 6-membered ring formed together with the oxygen atom is fused to a phenol nucleus. Specific examples of compounds preferred for the present invention are listed below. A specific example of a phenol derivative in which the ortho position of the hydroxyl group is substituted with a tertiary alkyl group. Specific examples of bisphenol derivatives. Specific example of phosphate ester. Examples of phenol derivatives in which the para-position is substituted with an oxygen atom and a 5- or 6-membered ring formed together with the oxygen atom are condensed to a phenol nucleus are compounds represented by the following general formula (). General formula () In the formula, R is a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, a cycloalkyl group,
Aryl group, heterocyclic group, or R ₄ CO−, R ₅ SO ₂
-, R ₆ NHCO-, and R ₄ , R ₅ and R ₆ each represent a substituted or unsubstituted alkyl group, alkenyl group, cycloalkyl group, aryl group or aralkyl group. R ₁ , R ₂ , and R ₃ are hydrogen atoms, halogen atoms, substituted and unsubstituted alkyl groups, alkylthio groups, alkoxy groups, aryl groups, aryloxy groups, arylthio groups, acyl groups, acylamino groups, acyloxy groups, and sulfones. An amide group, an alkylamino group, a cycloalkyl group, or an alkoxycarbonyl group, and Z represent an atomic group necessary to form a chroman or coumaran ring, and the chroman or coumaran ring is a halogen atom,
Alkyl group, alkylthio group, alkoxy group, alkenyl group, alkenyloxy group, aryl group,
It may be substituted with an aryloxy group, an N-substituted amino group, a heterocyclic group, or a residue forming a fused ring. Specific examples are given below. The compound represented by the above general formula () is disclosed in U.S. Patent Nos. 3432300, 3574627, and 3573050.
No., Special Publication No. 49-20977, Japanese Patent Publication No. 147433-1972,
No. 53-17729, No. 53-20327, No. 53-52421
and No. 53-77527. According to the present invention, when the following hydroquinone antioxidant is used in combination with the dye pixel anti-fade agent, the anti-fade effect of the dye image is further improved. According to the present invention, when an ultraviolet absorber is used in combination with a dye image fading inhibitor, the effect of preventing fading and discoloration of the dye image and non-printed areas is significantly amplified. The ultraviolet absorber that can be more preferably used in the present invention is a non-diffusible 2-hydroxyphenyl-substituted benzotriazole compound represented by the general formula (). General formula () R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a carbalkoxy group, an aryloxy group or an aryl group. Some hydroxybenztriazole ultraviolet absorbers are available commercially, but
-10466 and Japanese Patent Publication No. 42-26187. Specific examples of the compound represented by the general formula () are listed below. (-1) 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (-2) 2-(2'-hydroxy-3'・5'-di-t-
butylphenyl)benzotriazole(-3) 2-(2'-hydroxy-3'・5'-di-t-
butylphenyl)-5-chlorobenzotriazole(-4) 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole(-5) 2-(2'-hydroxy-5'-t-butylphenyl)-5 -chlorobenzotriazole(-6) 2-(2'-hydroxy-3'-sec-butyl-
5'-t-butylphenyl)benzotriazole (-7) 2-(2'-hydroxy-3'-sec-butyl-
5′-t-butylphenyl)-5-chlorobenzotriazole(-8) 2-(2′-hydroxy-4′-n-hexyloxyphenyl)benzotriazole(-9) 2-(2′-hydroxy-5 '-isooctylphenyl)benzotriazole (-10) 2-(2'-hydroxy-3',5'-di-t-
amyl phenyl) benzotriazole (-11) 2-(2'-hydroxy-5'-isooctylphenyl)-5-methylbenzotriazole In the present invention, the dye image fading inhibitor, hydroquinone antioxidant, and ultraviolet absorber are , a solvent dispersion technique in an aqueous hydrophilic colloid coating liquid used to form a coating layer provided on the surface of a support for adsorbing a coloring component, or in a hydrophilic colloid layer combined with the coating layer. mixed by using. Dye image anti-fade agents, hydroquinone antioxidants, and ultraviolet absorbers are either high-boiling point, water-immiscible organic solvents, low-boiling point organic solvents, or water-soluble organic solvents, or high-boiling point organic solvents that are not water-miscible. and/or a mixture of a low-boiling point organic solvent and/or a water-soluble organic solvent, and then the solvent solution of the UV absorber of general formula () is sufficiently dispersed in an aqueous solution of gelatin or other hydrocolloid. Mix. Any of the high boiling water immiscible organic solvents described in US Pat. No. 2,322,027 can be used as the solvent. Typical examples of high boiling point organic solvents include di-n-
Examples include butyl phthalate, benzyl phthalate, triphenyl phosphate, tri-o-cresyl phosphate, diphenyl-mono-pt-butylphenyl phosphate, tri-pt-butylphenyl phosphate, and the like. According to the present invention, the pigments coated on the recording sheet include zeolite, vermiculite, kaolinite, halloysite, acid-treated halloysite, attapulgite, diatomaceous earth, silicic anhydride, aluminum silicate, calcium silicate, Magnesium silicate, etc. can be used. The effects of the present invention will be further enhanced if an adhesive that adsorbs dye is used as the adhesive for the dye-adsorbing pigment. Adhesives that adsorb such dyes include sodium polyacrylate, styrene-maleic anhydride copolymer sodium salt, methyl vinyl ether-maleic anhydride copolymer, and ethylene-maleic anhydride copolymer.
Maleic anhydride copolymer, polystyrene sulfonate, carboxymethyl cellulose, cellulose sulfate, carboxy-modified polyvinyl alcohol, sodium alginate, gum arabic, polyethyleneimine, polyamide-polyamine resin, cationic starch, casein, soybean protein, dimethyl acrylate An aminoethyl methacrylate copolymer, an acrylic ester copolymer emulsion having a cationic dissociative group, and the like can be used as the dye-adsorbing adhesive. Starch, polyvinyl alcohol, methylcellulose, hydroxyethylcellulose, hydroxyethylated starch, polyacrylamide, polyvinylpyrrolidone, basic latex polymer, and the like can be used as components of the pigment coating layer other than the adhesive. When inkjet recording is performed on an inkjet recording sheet containing a basic polymer latex according to the present invention with an aqueous ink containing a direct dye or an acidic dye having an anionic dissociative group, the dye in the aqueous ink and the inkjet recording sheet are mixed with each other. The basic polymer latex is ionically bonded, making the dye insolubilized and completely preventing dye elution. Basic polymer latex is water insoluble;
Since the dye has a strong mordant power, the inkjet recorded image has complete water resistance, and no change in the image is observed even if the inkjet recorded image is exposed to water or immersed in water for a long time. Specific examples of basic latex polymers that can be used in the present invention are shown below. The present invention will be explained in more detail with reference to Examples below. Example 1 A dye image anti-fading agent, a dye image anti-fading agent and a hydroquinone antioxidant, a dye image anti-fading agent, a hydroquinone antioxidant were added to ^one side of a base paper ^with a basis weight of 100 g/m 2 and a cob size of 25 g/m 2 A sample was prepared by applying a mixed suspension of a pigment dispersion and a mixture of a UV absorber and a UV absorber. After dissolving the anti-fading agent of the present invention as shown in Table 1 in a high-boiling point solvent and a low-boiling point solvent by heating at 65°C, emulsification and dispersion in 30 c.c. of a 10% by weight gelatin aqueous solution containing saponin using a colloid mill, Add 15 c.c. of water and mix. This emulsion was mixed with 5% gelatin and hydroxyethyl cellulose.
1.5% by weight, 7% by weight of synthetic aluminum silicate,
A suspension containing 0.5% by weight of hardener polyamine-polyamide-epichlorohydrin resin is mixed in a colloid mill, and the resulting suspension has a dry solid content of 8%.
g/m ² on one side of the base paper using an air knife coater and calendering to prepare inkjet recording sheet samples 1 to 9.
(However, sample 1 is a comparative sample without the addition of the compound of the present invention.) In the recording sheet samples 1 to 9 thus obtained, 4
Four-color aqueous ink of yellow, magenta, cyan, and black was ejected using a multicolor inkjet printer having multiple inkjet nozzles to perform single-color and two to four-color overlapping recording. This sample was subjected to a sunlight exposure test after measuring the density of yellow, magenta, cyan, and black images and the stain density (measured as yellow density) of the non-printed area using a Masbeth reflection densitometer RD-514. It was exposed to sunlight for 7 days at a 45° south facing position under direct sunlight.
After exposure, the yellow density of each color and non-printed area was measured again, and the percentage of the density after exposure (D) to the density before exposure (D ₀ ) was determined (D/D ₀ × 100), and this was taken as the fading rate. . The results are shown in Table 1.

【table】

【table】

[Table] As is clear from the results in Table 1, Samples 2 to 9 according to the present invention showed significant fading and contamination concentration of yellow, magenta, cyan, and black ink compared to Sample 1 without the addition of the compound of the present invention. suppressed. Yellow, magenta, and
Cyan and black water-based inks are prepared by heating the following composition to 50-60°C and stirring for 1 hour.
0.8μ microfilter (manufactured by Fuji Photo Film,
FM type). -Yellow ink- Dye (yellow dye example (Y-1)) 3.0 parts by weight N・N'-dimethoxymethyl-2(1H)-pyrimidinone (-3) 20.0 〃 Neugen P (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 0.1 〃 Triethanolamine 5.0 〃 Water 71.9 〃 - Magenta ink key dye (Magenta dye example (M-2)) 1.5 parts by weight N・N'-dimethoxymethyl-uron (-2)
20.0 〃 Neugen P 0.1 〃 Diethylene glycol monoethyl ether
0.5 〃 Triethanolamine 1.0 〃 Water 76.9 〃 -Cyan ink- Dye (sodium copper phthalocyanine tetrasulfonate) 2.4 parts by weight N・N'-dimethoxymethylimidazolidinone (-2) 20.0 〃 Diethylene glycol monobutyl ether
0.5 〃 Diethylene glycol 1.5 〃 Neugen P 0.1 〃 Triethanolamine 2.0 〃 Water 73.5 〃 -Black ink dye (CI acid black 155) 3.0 parts by weight N・N'-dimethoxymethyl-imidazolidinone (V-2) 20.0 〃 2. 2'-thiodiethanol 10.0 〃 Neugen P 0.1 〃 Diethylene glycol monoethyl ether
1.0 〃 Triethanolamine 2.0 〃 Water 63.9 〃 Example 2 On one side of a base paper with a basis weight of 150 g/m ² and a cob size of 25 g/m ² , 5% by weight of gelatin and the basic latex polymer exemplified by the present invention (the amount added is the second (See table) Hydroxyethyl cellulose 1.5% by weight, diatomaceous earth 5
Dry suspension containing wt% solids 8.0g/ ^m2
Apply it with an air knife coater so that it looks like this.
After dissolving the anti-fading agents of the present invention (see Table 2 for the amounts added) in 0.8 cc of tri-o-cresyl phosphate and 9 cc of ethyl acetate by heating at 65°C, 10% by weight gelatin containing saponin was added. Emulsified and dispersed in 30 c.c. of aqueous solution with a colloid mill, rinsed with 30 c.c. of water, cooled,
Noddled and dried. 6% dry substance by weight
Gelatin 30c.c., 7.5% by weight saponin 4c.c. and water
Redispersed in a solution containing 50 c.c. This dispersion was overcoated onto the pigment layer of the pigment-coated paper using an air knife coater to give a dry solid content of 2.5 g/m ² and calendered to prepare inkjet recording sheet samples 10 to 14. (However, sample
Sample No. 10 is a comparative sample without the addition of the anti-fading agent of the present invention. ) These samples were subjected to inkjet printing, sunlight exposure, and reflection density measurement in the same manner as in Example 1, and the water resistance rate of the recorded images was also measured by the following method. The reflection density of a sample inkjet printed with cyan ink was measured, and the sample was immersed in running water for 1 hour. After taking it out and drying, the cyan reflection density was measured, and the ratio to the reflection density before soaking was expressed as a percentage to give the water resistance rate. The results shown in Table 2 were obtained.

【table】

【table】

[Table] As is clear from the results in Table 2, Samples 11 to 14 according to the present invention significantly suppressed the fading rate and contamination concentration of yellow, magenta, cyan, and black inks compared to samples without anti-fading agents. ing. Furthermore, the addition of the basic latex polymer resulted in a significantly improved water resistance rate, and it is clear that the present invention was able to achieve water resistance and light resistance of recorded images.

Claims (1)

[Claims] 1 In the recording image forming method of inkjet printing, at least one of the ortho positions of the hydroxyl group is substituted with tertiary alkyl using an aqueous inkjet ink whose main components are a water-soluble acid dye or a water-soluble direct dye, a wetting agent, and water. Phenol derivatives, bisphenol derivatives, compounds containing a phenol derivative as part of the phosphoric acid ester, the para position is substituted with an oxygen atom, and the 5- or 6-membered ring formed with this oxygen atom is a phenol nucleus. 1. An inkjet recording image forming method comprising inkjet printing on a recording sheet containing at least one dye image fading inhibitor selected from phenol derivatives condensed with phenol derivatives.