JP3533752B2 - Recording medium and recorded matter for inkjet printer - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates, Lee inkjet printer for inkjet printers Symbol <br/> recording medium suitable for recording by (hereinafter, simply referred to as recording medium), and a recorded matter recorded thereto.

[0002]

2. Description of the Related Art Various full-color printers such as an inkjet system, a sublimation type thermal transfer system, and an electrostatic transfer system are known. Among them, inkjet printers are rapidly becoming popular because they are easy to achieve full color and have low printing noise.

In this system, ink droplets are ejected from a nozzle toward a recording medium at high speed, and the ink contains a large amount of solvent. Therefore, a recording medium for an inkjet printer is required to quickly absorb the ink and have excellent color forming properties. As such a recording medium, one in which a porous layer of alumina hydrate is provided on a substrate is known (JP-A-2-276670,
(See Japanese Patent Laid-Open No. 2-276671).

[0004]

In general, since water-soluble ink is used in an ink jet printer, the durability is not always high, and fading may be observed after long-term storage. It is an object of the present invention to obtain a recording medium which has good ink absorbency and is capable of stably recording for a long period of time with high color reproducibility and color density.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a base material, grayed
Lysine, alanine, valine, α-aminobutyric acid, γ-ami
Nobutyric acid, β-alanine, taurine, serine, ε-amino
-N-caproic acid, leucine, norleucine and fe
It is intended to provide a recording medium containing a porous ink receiving layer mainly containing hydrated alumina and containing any amino acid selected from the group consisting of nylalanine .

The base material is not particularly limited and various materials can be used. Specifically, polyester resins such as polyethylene terephthalate, fluorine resins such as ETFE, various plastics such as polycarbonate, and paper can be preferably used. Further, glass and metal can also be used. These substrates may be subjected to corona discharge treatment, undercoating or the like for the purpose of improving the adhesive strength of the porous layer ink receiving layer.

Porous ink receiving layer formed on a substrate
Is mainly alumina hydrate . In particular, a structure in which alumina hydrate particles are bound with an organic binder is preferable. Aluminum
Nahydrate particles are boehmite (Al ₂ O ₃ · nH ₂ O,
It is preferable that n = 1 to 1.5) because the ink absorbency of the ink jet printer is good and the fixing property of the dye in the ink is excellent.

In the case where the porous layer containing the hydrated alumina particles has a pore structure substantially consisting of pores having a radius of 1 to 15 nm and a pore volume of 0.3 to 1.0 cc / g. Is preferable because it has sufficient absorbency and the porous layer is also transparent. The pore size distribution is measured by the nitrogen adsorption / desorption method. In the case of such a highly transparent ink receiving layer, if a transparent plastic film or the like is used as the substrate,
It is possible to obtain a transparent recorded material that can be used for an OHP (overhead projector) or the like. As a base material
When an opaque plastic film containing a white pigment or paper is used, a recorded matter with high resolution and high color density can be obtained.

In the present invention, an amino acid is a compound having an amino group and a carboxylic acid group in the same molecule. α,
Any type of amino acid such as β and γ may be used. Although some amino acids have optical isomers, in the present invention, there is no difference in the effect due to optical isomers, and any isomer can be used alone or similarly in a racemic form.

Amino acids have the effect of suppressing the fading of pigments. In the present invention , glycine, alanine, valine, α
-Aminobutyric acid, γ-aminobutyric acid, β-alanine, taurine, serine, ε-amino-n-caproic acid, leucine,
Selected from the group consisting of norleucine and phenylalanine
Use whichever one you find . Of these, alanine and ε-
Amino-n-caproic acid is especially preferred. They are,
Amino acid alone has the effect of preventing discoloration, but when used in combination with thiocyanate, the effect of preventing discoloration becomes greater. Amino acids having a solubility in water at 25 ° C. of 5 or more are preferable because they are easy to handle. The solubility is the maximum amount of solute that can be dissolved in 100 g of the solvent, which is represented by g.

The amino acid is preferably used in an amount of 0.1 to 15% by weight based on the porous ink receiving layer. If the amino acid content is less than 0.1% by weight, the effect of adding the amino acid is not sufficiently exhibited and ink fading may occur, which is not preferable. If the amino acid is greater than 15% by weight,
It is not preferable because it may impair the absorbability of the ink. 1 to 10 amino acids are contained in the porous ink receiving layer.
It is particularly preferable if the content is wt%.

The solubility of amino acids in water is 0.
When it is in the range of 1 to 5, it also has an effect of imparting appropriate hydrophobicity without affecting the pore structure of the porous ink receiving layer and preventing ink bleeding. If the solubility of the amino acid in water is less than 0.1, the hydrophobicity is too large and the absorptivity of the ink may be impaired, which is not preferable. When the solubility exceeds 5, the effect of imparting hydrophobicity is small and the effect of suppressing ink bleeding is small, which is not preferable.

Specific examples of amino acids highly effective in preventing bleeding include α, such as aspartic acid, alloisoleucine, isoleucine, glutamic acid, norleucine, phenylalanine, leucine, phenylglycine and glutamine.
-Amino acids, acetylglycine and the like. Norleucine is particularly preferable. It is preferable to use 0.1 to 15% by weight of these amino acids in the porous ink receiving layer. If the amino acid content is less than 0.1% by weight, the effect of adding the amino acid may not be sufficiently exhibited and ink bleeding may occur, which is not preferable. When the amino acid content is more than 15% by weight, it is not preferable because the hydrophobicity is strong and the ink absorbability may be hindered. It is particularly preferable that the amino acid content is 1 to 10% by weight based on the porous ink receiving layer.

The method for forming the porous ink receiving layer on the substrate is not particularly limited. For example, as a method for forming a porous layer containing an alumina hydrate, a method in which a coating liquid formed by adding a binder and a solvent to alumina hydrate is applied to a substrate and then dried is preferable. It is preferable to use alumina sol as a raw material for alumina hydrate because a porous layer having good transparency can be formed. The coating method of the coating liquid is, for example, a die coater, a roll coater,
Air knife coater, blade coater, rod coater, bar coater, comma coater, etc. can be adopted.
As a solvent for the coating liquid, either an aqueous system or a non-aqueous system can be adopted.

As the binder, polyvinyl alcohol and its modified products, starch and its modified products, SB
Organic substances such as R latex, NBR latex, carboxymethyl cellulose, hydroxymethyl cellulose, and polyvinylpyrrolidone can be used. The amount of the binder used is preferably about 5 to 50% by weight of the alumina hydrate. If the amount of the binder used is less than 5% by weight, the strength of the porous layer may be insufficient. On the contrary, if it exceeds 50% by weight, the ink absorption or the dye adsorption is insufficient. Therefore, it is not preferable because it may result in

[0016]

The thickness of the porous ink receiving layer is appropriately selected according to the specifications of the printer, but is generally 5-1.
It is preferable to adopt 00 μm. If the thickness of the porous ink receiving layer is less than 5 μm, the ink absorbency may be insufficient or the dye may not be sufficiently adsorbed.
If it exceeds m, the transparency of the porous ink-receiving layer may be impaired or the strength of the layer may be reduced, which is not preferable.

[0018] As a method for imparting amino acid to the porous ink-receiving layer is formed by forming a porous ink-receiving layer, the aqueous solution A Mi <br/> Bruno acid, is the preferred method of imparting an impregnation method or a spray method . It is also possible to employ a method in which the amino acid is directly and uniformly dissolved in the coating solution of alumina sol to form the porous ink-receiving layer.

The recording medium of the present invention is particularly suitable for recording using an ink containing a water-soluble dye and an aqueous solvent. The recorded matter obtained by supporting the water-soluble dye on the porous ink-receiving layer of the recording medium of the present invention using an inkjet printer has high resolution and does not cause bleeding even after a long period of time. Even in the case of full-color recording, the color reproducibility does not deteriorate due to bleeding of only a specific dye.

[0020]

The mechanism by which the amino acid suppresses the fading of the ink is not clear, but it is considered that the reaction of the lone electron pair of the amino group with ozone reduces the fading action of the dye by ozone.

Amino acids having a solubility in water of 0.1 to 5 are adsorbed on the porous ink receiving layer and have the effect of increasing the hydrophobicity thereof. Therefore, it becomes difficult for water and alcohols, which are ink solvents, to move through the ink receiving layer,
As a result, it is considered that the migration of dye molecules in the ink is suppressed. Similarly, the amino acid suppresses the movement of alcoholic solvents such as ethanol and glycol, which may be contained in the ink as a wetting agent, so that the ink is less likely to develop together with the solvent. Therefore, even when recording with ink, especially ink containing a large amount of non-volatile solvent,
It is considered that the deterioration of image quality such as bleeding is prevented.

[0022]

【Example】

Example 1 5% of the amino acid shown in Table 1 was dissolved in 100 g of alumina sol having a solid content of 18% by weight synthesized by hydrolysis / peptization method of aluminum alkoxide with respect to the weight of alumina, and further 32 g of a 6.2% by weight polyvinyl alcohol aqueous solution. To prepare a coating liquid. This coating solution was applied onto a white polyethylene terephthalate film (thickness 100 μm) by using a bar coater so that the coating amount after drying was 20 g / m ² to form an alumina hydrate layer. This was dried and then heat treated at 140 ° C. to obtain a recording medium. The physical properties of the coating layer are as follows: average pore radius 5.5 nm, pore volume 0.5 cc /
and the alumina hydrate was boehmite.

Regarding the above recording medium, an ink jet printer (manufactured by Seiko Epson Corporation, trade name MJ
700) was used to print a test pattern with a black ink containing Food Black 2 as a dye. Each recorded material was exposed indoors for 30 days to evaluate the degree of black fading. No clear discoloration was observed in comparison with the clear discoloration observed when no amino acid was added.

[0024]

[Table 1]

Example 2 1 part by weight of polyvinyl alcohol was added to 5 parts by weight of the alumina sol of Example 1, and water was further added to prepare an alumina sol coating liquid having a solid content of 10% by weight. Apply this coating solution to a white polyethylene terephthalate film (thickness 100 μm
m) was coated using a bar coater so that the coating amount after drying was 20 g / m ² to form an alumina hydrate layer. This was dried and then heat treated at 140 ° C. to obtain a recording medium. The physical properties of the coating layer were an average pore radius of 5.5 nm and a pore volume of 0.5 cc / g, and the alumina hydrate was boehmite.

This recording medium was prepared by using one of the amino acids shown in Table 2.
The coating layer was dipped in a 0% by weight aqueous solution to uniformly apply the solution. This was hung vertically and air-dried, and then heated and baked at 140 ° C. for 4 minutes in a drum dryer. By dipping this recording medium in ion-exchanged water for 12 hours and quantifying the amount of amino acid in the solution by ion chromatography,
The amount of amino acid in the coating layer (% by weight with respect to the porous layer) was determined. The results are shown in Table 2. When the color fading properties of the ink were evaluated in the same manner as in Example 1, no color fading was observed as compared with the case where no amino acid was added.

[0027]

[Table 2]

Example 3 A recording medium was prepared in the same manner as in Example 1 except that the amino acids shown in Table 3 were used instead of the amino acids shown in Table 1. A test pattern was printed on this recording medium with an ink (magenta) containing a water-soluble dye using an inkjet printer (manufactured by Seiko Epson Corporation, trade name MJ700). After each medium was left in an environment of 30 ° C. and 80% for 8 hours, bleeding was evaluated by visual observation. When no amino acid was added, bleeding was observed, but no discoloration was observed in any case.

[0029]

[Table 3]

Reference Example A coated paper (silica layer having a thickness of 15 μm) obtained by coating porous silica particles on a paper substrate was dipped in a 10% by weight aqueous solution of amino acid shown in Table 4 to form a coating layer. The solution was evenly applied to. This was hung vertically and air-dried, and then heated and baked at 140 ° C. for 4 minutes in a drum dryer. This recording medium was immersed in ion-exchanged water for 12 hours, and the amount of amino acid in the solution was quantified by ion chromatography to determine the amount of amino acid in the coating layer (% by weight based on the porous layer). The results are shown in Table 4. When the color fading properties of the ink were evaluated in the same manner as in Example 1, no color fading was observed as compared with the case where no amino acid was added.

[0031]

[Table 4]

[0032]

The recording medium of the present invention has high ink absorbency and fixability, and is capable of maintaining good image quality for a long period of time. In particular, it is suitable for recording using a water-soluble ink and is suitable as a recording medium for an inkjet printer.

Claims (5)

(57) [Claims] 1. Glycine, alanine, valine,
α-aminobutyric acid, γ-aminobutyric acid, β-alanine, tau
Phosphorus, serine, ε-amino-n-caproic acid, leucine
Group consisting of benzene, norleucine and phenylalanine
Ri contains any amino acid selected, and the ink having a porous ink-receiving layer mainly containing alumina hydrate
Recording medium for jet printers . 2. The solubility of the amino acid in water is 0.1.
The inkjet printer according to claim 1, wherein
Use a recording medium. 3. The recording medium for an ink jet printer according to claim 1, wherein the alumina hydrate is boehmite. 4. The porous ink receiving layer has a pore radius of 1 to 1.
The inkjet printer according to claim 1, 2 or 3, which has a pore volume of 0.3 to 1.0 cc / g at 5 nm.
Use a recording medium. 5. Inkuji according to any one of claims 1-4
A recording material in which a water-soluble dye is carried in the ink receiving layer of a recording medium for a wet printer .