JP2003312132A - Recording medium for ink jet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium for ink jet which is excellent in outward appearance and free from a blur and cockling and has a recording part reproducing a wide range of color gamut, in particular, and which is also suitably used for proofreading of a print, in the case when information such as an image or a character is recorded by an ink jet printer. <P>SOLUTION: The recording medium for ink jet has an ink receiving layer provided at least on one side of a substrate. The ink receiving layer is provided at least with an intermediate layer and a dye fixing layer in this sequence from the substrate. Noncoated paper is used for the substrate, while at least a silanol-modified polyvinyl alcohol or the like and a filler are used for the intermediate layer, and at least a cationic dry silica having an average particle size of 0.4 μm or below and a binder are used for the dye fixing layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ink jet printer for recording information such as images and characters, which has a good appearance and does not cause bleeding or cockling. The present invention relates to an inkjet recording medium that is also suitable for print proofing.

[0002]

2. Description of the Related Art In recent years, various types of printers for computer output have become widespread. Among them, the inkjet printer is excellent in quietness, cost, simplicity, and image quality, can reproduce a full-color image with high quality, has excellent performance not found in other methods, and is expected to be further popularized.
Particularly in recent years, with the control of ink droplets, the development of dark and light inks, and the improvement of the performance of recording media, the technology has advanced to the point where an image comparable to a silver salt photograph can be obtained.

With the development of such technology, ink jet printers are increasingly used also for print proofing of offset printing and gravure printing. Print proofing with an inkjet printer makes it possible to implement a remote proofing system and thus a quick proofing.

In the above ink jet recording system,
As the ink, use a water-based ink in which the dye is dissolved,
As the recording medium, a recording medium having an ink receiving layer formed on a support is generally used.

To give a general example of a recording medium, a recording medium having a porous silica dispersed in polyvinyl alcohol and a cation component added thereto as an ink receiving layer provides an ink by a physical action. Method to chemically fix the dye by adding cation component to silica pores, or to use alumina sol to chemically fix the dye with alumina while physically absorbing the ink. Alternatively, there is a method in which a cationic resin is used to chemically fix the dye by the cation portion while physically absorbing the ink by swelling.

However, many of such general recording media have been developed for the purpose of improving image quality, glossiness, dryness and water resistance, targeting silver salt photographs. Therefore, many of these characteristics are satisfactory, but the color gamut reproduction range cannot satisfy the color gamut reproduction range of offset printing or gravure printing, and it is not practical for print proofing.

For example, in the case of an ink jet recording medium in which ink is absorbed into the pores by a physical action,
Although the ink absorbability is excellent, since the dye develops color inside the receiving layer, the original hue of the dye cannot be obtained and the color reproduction range becomes narrow. As an example, JP-A-11-3
48409, JP-A-2000-94830,
Japanese Patent Laid-Open Nos. 2000-212234 and 2000-3
The inkjet recording medium having fine pores formed by fine particles proposed in Japanese Patent Application Laid-Open No. 09157, 2001-96911 and the like has excellent ink absorbability and image quality, but has a gamut reproduction range. Does not satisfy the gamut reproduction range in offset printing or gravure printing,
It was insufficient for calibration.

Further, in the case of an ink jet recording medium which absorbs ink by swelling, the use of a transparent resin makes it possible to obtain a dye close to the original hue of the dye and to widen the color gamut reproduction range. However, since the ink is absorbed, the ink absorption speed is slow, and it has not been possible to obtain high image quality with recent high-speed inkjet printers.

[0009]

That is, the prior art is suitable for obtaining a texture and printed matter similar to silver halide photographs, but with regard to the color gamut reproduction range, the color gamut of offset printing or gravure printing is provided. It was insufficient for the reproduction range. Generally, in offset printing or gravure printing, image information is recorded by placing ink on a dedicated printing paper based on the image information, and drying or curing the ink. that time,
Although some of the printing ink penetrates inside the paper, most of it usually stays on the surface of the paper, and therefore most of the pigment, which is the coloring component, also stays on the surface. The hue is fully expressed. On the other hand, in ink jet printing, the ink jet ink basically permeates into a coating layer called an ink receiving layer, and therefore a dye, which is a coloring component, also permeates into the inside of the ink receiving layer to be fixed and develop a color. Therefore, in addition to the transparency of the film of the ink receiving layer, the refractive index, etc., the coloring is also affected by the components other than the dye in the ink, that is, the residual solvent and the additive, and the hue originally possessed by the dye is not sufficiently expressed. In many cases. Therefore, when an inkjet printer is used for color calibration such as offset printing or gravure printing, the color reproduction range of the offset printing or gravure printing is the same as that of the conventional inkjet recording medium, even if the image quality and blurring of characters are excellent. It was narrow and was not enough for practical use.

The present invention has been made in view of the above problems of the conventional technique, that is, when recording information such as images and characters by an ink jet printer, the aesthetic appearance is good and blurring is not caused. The present invention relates to an inkjet recording medium that does not cause cockling and has a wide color gamut reproduction range of a recording unit, which is suitable for print proofing.

[0011]

The present invention has been made to achieve the above object, and the invention as set forth in claim 1 provides an intermediate layer on at least one surface of a support made of non-coated paper. In an inkjet recording medium provided with an ink receiving layer having a dye fixing layer, at least silanol-modified polyvinyl alcohols and a filler are used in the intermediate layer, and the dye fixing layer has at least average particles. An ink jet recording medium comprising a cationic dry silica having a diameter of 0.4 μm or less and a binder.

According to this, when characters and image information are recorded by an ink jet printer, the obtained image quality is excellent, and there is no cockling or waviness in the recording section, and particularly, a wide color gamut reproduction range, It is possible to obtain an inkjet recording medium that can also be used for print proofing applications such as offset printing and gravure printing.

This has an average particle size of 0.4 μm in the dye fixing layer.
The use of cation-modified dry silica with a m or less cation and a binder improves the fixability of the dye due to its cation component, so that many dyes are fixed on the upper part of the dyeing layer. Further, among the fillers, dry silica has a relatively large specific surface area and thus has good color development. Further, when the average particle size is 0.4 μm or less, the wavelength of light is below the visible wavelength range, so that the transparency of the dye fixing layer is increased and the color developability is further improved, and a wide color gamut reproduction range is achieved and the surface of the receiving layer is It is possible to obtain a recording medium which is smoothed and has an appropriate surface gloss close to that of a printing proof sheet. Further, by using silanol-modified polyvinyl alcohols and a filler in the intermediate layer, the porous layer weakly cross-linked by the silanol group has an appropriate absorption capacity, and the intermediate layer contains a solvent or an additive other than the dye in the ink. It is considered that the dye molecules in the dye fixing layer tend to be present independently, and a wide color gamut reproduction range is achieved. Similarly, by using a non-coated paper for the support, the solvent and additives permeate more appropriately than the coated paper, and the dye molecules in the dye fixing layer are likely to exist independently, so that a wide color gamut reproduction range can be obtained. Thought to be achieved.

Further, by using wet silica having an average particle diameter of 2 to 5 μm as the filler of the intermediate layer, the solvent other than the dye and the additives in the ink can be more effectively maintained while maintaining the smoothness of the recording medium. A wide color gamut is achieved by being absorbed into the intermediate layer.

The support has an air permeability of 300 seconds or less / 1
Even when the non-coated paper of 00 CC is used, the solvent other than the dye in the ink, the additives, and the like are more effectively absorbed in the intermediate layer while maintaining the smoothness of the recording medium, and a wide color gamut reproduction is achieved.

Further, in the ink receiving layer, the amount of the cationic dry silica in the dye fixing layer is 40 to 120 parts by weight with respect to 10 parts by weight of the binder, so that the dye fixing layer can quickly transfer the ink from the ink receiving layer. It is possible to obtain sufficient voids to be absorbed inside the dye fixing layer and reduce image defects such as bleeding and beading and defective drying. By setting the amount of the filler in the intermediate layer to 20 to 50 parts by weight with respect to 10 parts by weight of silanol-modified polyvinyl alcohol, the solvent and additives other than the dye in the ink are more effectively absorbed in the intermediate layer. An inkjet image receiving paper having a wider color gamut can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording medium of the present invention will be described in detail below. The inkjet recording medium according to the present invention is an inkjet recording medium having a wide color gamut reproduction range that is sufficiently practical for print proofing applications such as offset printing and gravure printing.

The ink receiving layer described in the present invention is a layer capable of sufficiently absorbing the ink ejected from the ink jet printer, and is composed of at least two layers of an intermediate layer and a dye fixing layer. The dye fixing layer is a layer that can mainly fix the dye in the ink, and the intermediate layer is a layer that can mainly absorb the solvent, additives, etc. in the ink. The support is a base material on which an ink receiving layer can be formed on at least one surface.

The silanol-modified polyvinyl alcohols described in the present invention are polyvinyl alcohols having a silanol group, and the saponification degree and the polymerization degree are not particularly specified, but in order to increase the strength of the film, it is 1000 or more. It is preferable to use one having a polymerization degree. Further, the filler in the present invention is a commonly used filler, and examples thereof include silica, kaolin, clay, calcium carbonate, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, aluminum hydroxide and the like. . In particular, when wet silica produced by the gel method or the precipitation method is used, the oil absorption is high,
It is preferable because it has excellent ink absorbability, and by using wet silica having an average particle diameter of 2 to 5 μm, an intermediate layer having excellent smoothness of the receiving layer and excellent ink absorbency can be obtained.
In this case, if the average particle size is smaller than 2 μm, sufficient voids cannot be formed in the intermediate layer to absorb the ink,
If it is larger than 5 μm, the smoothness of the receptive layer will be poor and not only a matte tone will be obtained, but also the dots of the printed ink will be disturbed and the image quality will be degraded.

The dry silica described in the present invention is also called a vapor phase silica, and is generally a silica produced by burning silicon tetrachloride with hydrogen and oxygen. The feature is that the particles are very fine. There is something. In particular, the dry silica used in the present invention has an average particle size of 0.4 μm or less, which can obtain the surface smoothness and transparency of the dye fixing layer, in order to improve the surface gloss and ink colorability of the ink receiving layer. The average particle size of dry silica referred to here is a secondary particle size, and dry silica generally has a finer particle size of 1
Since the secondary particles cannot exist in the secondary particles but exist as secondary particles which are aggregates thereof, in practice, secondary particles having a diameter of 0.1 μm to 0.4 μm can be used. Further, the cationic silica is one in which the surface of dry silica is cationized with a cationic compound. Usually, untreated dry silica has an anionic surface, but it is sufficiently cationized to completely cationize the surface. Make it sex.

As the cationic compound, an organic compound,
Any inorganic compound may be used. Further, not only a compound having an electrically positive charge, but also a compound having a functional group which exhibits a cationic property by electrolysis in a state of being dispersed in water may be used.

For example, a method of cationizing the surface of dry silica with an organic compound or polymer having a quaternary ammonium salt, or a surface treatment of dry silica with an organic compound or polymer having an amine, and then halogen treatment. Method of cationizing as an amine salt by treatment with an alkyl halide or Lewis acid, or a method of cationizing by performing surface treatment of dry silica with an inorganic compound of alumina, titanium, magnesium or its oxide, an organic compound having an amino group There is a method in which the surface of dry silica is treated with a polymer or a polymer, and the surface is cationized by dispersing it in water and electrolyzing the amino groups. In the method of cationizing the surface by electrolysis, it is necessary that the pH of the colloidal dispersion of dry silica is sufficiently lower than the pH of its isoelectric point.

Any binder may be used in the dye fixing layer of the present invention. Generally, polyvinyl alcohols, urethane resins, acrylic resins, ester resins are used by dissolving them in a solvent, or It is used after being self-emulsified or emulsified with an emulsifier. At that time, it is important to select a binder that does not cause aggregation of the cationic dry silica. In particular, when polyvinyl alcohols are used, not only can inkjet recording media with high image quality and a wide color gamut reproduction range be produced at low cost, but also the dispersion stability of cationic dry silica is good, and dye fixing with excellent coating stability is achieved. A layer coating solution can be obtained. Furthermore, in order to enhance this stability, the pH of the dye fixing layer coating solution is set to 6.
It is preferable to adjust the pH to 0 or less, and further to pH 5.0.
The following is more preferable.

The non-coated paper described in the present invention is a paper whose surface is not coated, and general high-quality paper and medium-quality paper are used. Among them, those having an air permeability of 300 seconds or less / 100 CC are preferably used in order to effectively permeate the solvent and additives in the ink from the dye fixing layer to the intermediate layer. When ink is printed on the dye fixing layer, if the air permeability is greater than 300 seconds, the gas in the voids in the intermediate layer and the dye fixing layer does not easily move to the paper side, which is the support, and also replaces the ink. It becomes difficult to do so that the ink cannot penetrate quickly in the depth direction. For this reason, not only the image bleeding and beading are likely to occur, but also the non-volatile solvent and the additive are not separated from the ink in the dye fixing layer, and the color gamut remaining in the dye fixing layer is narrowed. . The size and whiteness are not particularly limited,
With a sizing agent internally added, the Steckigt sizing degree is approximately 1
When it is 5 seconds or more, it is preferable because the step of applying the ink receiving layer becomes easier, but if the Steckigt sizing degree is too high, the absorptivity is lowered, and the bleeding and the color gamut reproduction range are lowered. , Consider the balance and select an appropriate one.

The mixing ratio of the silanol-modified polyvinyl alcohols and the filler in the intermediate layer is preferably 20 to 50 parts by weight with respect to 10 parts by weight of the silanol-modified polyvinyl alcohols. When the proportion of polyvinyl alcohols is large, voids are not formed and the ink absorbency is poor, and as a result, the dryness of the ink image-receiving layer is poor, and when the proportion of fillers is high, the strength of the coating film decreases, resulting As a result, the surface strength of the ink receiving layer decreases.

The mixing ratio of the cationic dry silica and the binder in the dye fixing layer is preferably 40 to 12 cationic dry silica in the dye fixing layer with respect to 10 parts by weight of the binder.
0 parts by weight. When the proportion of the cationic dry silica is increased, the strength of the coating film is lowered, and problems such as powder falling occur, and cracks on the film surface are conspicuous and the aesthetic appearance is deteriorated. Further, if the proportion of the binder is increased, the absorbability is lowered, the occurrence of bleeding is increased, and the color gamut reproduction range is narrowed.

The coating amount of the intermediate layer is usually 10 to 40 g /
It is about m ² , preferably about 15 to 30 g / m ² . If the thickness is too thin, the ink absorbency is lowered, and the surface of the ink receiving layer is adversely affected such as bleeding, slow drying, and cockling. On the other hand, if the thickness is too large, the cost becomes high, and curling, cracking, and powder falling occur, which is not preferable.

The coating amount of the dye fixing layer is usually 3 g to 20 g.
g / m ² approximately, and preferably from 5 to 15 g / m ² approximately. If the thickness is too thin, the dye fixing ability will be insufficient, bleeding will occur and the color gamut will be narrowed.On the other hand, if the thickness is too thick, the cost will be high, curling and cracking,
It is not preferable because powder drop occurs.

The support is usually preferably about 80 to 200 g / m ² for good transportability to an ink jet printer.

In the present invention, in the ink receiving layer, if necessary, a crosslinking agent, a dye fixing agent, a tendency brightening agent, a surfactant, an antifoaming agent, a pH adjusting agent, an antiseptic agent, an ultraviolet absorbing agent, and a dispersing agent. Additives such as agents may be optionally selected from conventionally known ones within a range that does not prevent the object of the present invention.

The ink receiving layer may be provided on one side or both sides of the support. However, if provided on one side, it may be provided on the opposite side of the ink receiving layer as necessary to prevent curling and improve transportability to the printer. A back layer can be provided on the surface.

In producing the ink jet recording medium of the present invention, a conventionally known method of dispersing, mixing or dissolving a resin, a filler and an additive with a dispersing machine or the like may be used.

Also in coating, the surface of the support is coated by a known method, for example, a roll coater method, a flade coater method, an air knife coater method, a gate roll coater method, a size press coater method or the like. Then, it is dried using a hot air drying oven, a heating drum, etc. to obtain the inkjet recording medium of the present invention.

<Operation> As described above, according to the ink jet recording medium of the present invention, when information such as images and characters is recorded by the ink jet printer,
It is possible to obtain an inkjet recording medium which has a good appearance, has a texture close to that of printing paper without causing bleeding or cockling, and has a wide color gamut reproduction range of the recording portion, which is suitable for print proofing.

[0035]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. <Support> The paper used for the support was the one shown below. Support A Fine paper A (manufactured by Gojo Paper Co., Ltd.) 127.9 g / m ² (air permeability of 200 seconds / 100 CC) Support B B Fine paper B (manufactured by Gojo Paper Co., Ltd.) 127.9 g / m ² (air permeability 400 Second / 100 CC) Support C Coated Paper OK Top Coat N (manufactured by Oji Paper Co., Ltd.) 12
7.9g / m ² (air permeability 1000 seconds or more / 100CC)

<Intermediate layer> The ink used for the intermediate layer was prepared with the following composition. Intermediate layer A Wet silica X-37B (manufactured by Tokuyama Corporation) 10 parts by weight (average particle size 3.7 μm) Cyanol-modified polyvinyl alcohol R-1130 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Water 86 parts by weight Intermediate layer B wet silica X- 37B (manufactured by Tokuyama Corporation) 10 parts by weight Polyvinyl alcohol PVA-117 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Water 86 parts by weight Intermediate layer C Calcium carbonate μ-POWDER 3N (manufactured by Bihoku Kogaku Kogyo Co., Ltd.) 10 parts by weight (average particle diameter) 3 μm) Cyanol-modified polyvinyl alcohol R-1130 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Water 86 parts by weight Intermediate layer D Wet silica T-32 (manufactured by Tokuyama Corp.) 10 parts by weight (average particle size 1.6 μm) Cyanol modified polyvinyl alcohol R -1130 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Water 86 parts by weight Intermediate layer E Wet silica X-60 (Tokuyama Corporation) 10 parts by weight (average particle size 6 μm) Cyanol-modified polyvinyl alcohol R-1130 (manufactured by Kuraray) 4 parts by weight Water 86 parts by weight Intermediate layer F Wet silica X-37B (manufactured by Tokuyama) 12 parts by weight Cyanol-modified polyvinyl alcohol R-1130 (manufactured by Kuraray) 2 parts by weight Water 86 parts by weight Intermediate layer G Wet silica X-37B (manufactured by Tokuyama) 9 parts by weight Cyanol-modified polyvinyl alcohol R-1130 (manufactured by Kuraray) 5 parts by weight Water 86 parts by weight

<Dye fixing layer> The ink used for the dye fixing layer was prepared by the following composition. Dye fixing layer A Cationic dry silica A (average particle size 0.2 μm) 16 parts by weight Polyvinyl alcohol PVA-617 (manufactured by Kuraray Co., Ltd.) 2 parts by weight Water 82 parts by weight Dye fixing layer B Colloidal silica PS-MO (Nissan Chemical Industry) 16 parts by weight (average particle size 0.12 μm) Polyvinyl alcohol PVA-617 (manufactured by Kuraray Co., Ltd.) 2 parts by weight Water 82 parts by weight Dye fixing layer C Cationic dry silica B (average particle size 0.6 μm) 16 parts by weight Part Polyvinyl alcohol PVA-617 (manufactured by Kuraray Co., Ltd.) 2 parts by weight Water 82 parts by weight Dye fixing layer D Cationic dry silica A (average particle size 0.2 μm) 14 parts by weight Polyvinyl alcohol PVA-617 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Part Water 82 parts by weight Dye fixing layer E Cationic dry silica A (average particle size 0.2 μm) 15 parts by weight Polyvinyl chloride Alcohol PVA-617 (manufactured by Kuraray Co., Ltd.) 1 part by weight of water 84 parts by weight

<Preparation Method of Examples and Comparative Examples> An intermediate layer was coated on a support using a wire bar so that the dry coating amount was 20.0 g / m ^2, and dried at 100 ° C. for 5 minutes. . After that, the dye fixing layer was applied using a wire bar so that the dry coating amount was 10 g / m ^2, and the dye fixing layer was dried at 100 ° C. for 3 days.
After being dried for a minute, an inkjet recording medium was obtained.

An inkjet printer manufactured by Canon Inc. (product name B
J-F870), an evaluation image is formed, the color gamut reproduction range and the surface glossiness are confirmed, and the image quality, bleeding,
The cockling was evaluated. To confirm the color gamut reproduction range, use a colorimeter, a spectrino manufactured by Gretag Macbeth,
A 60 ° gloss meter was used to confirm the glossiness, and the glossiness of the surface of the receiving layer was measured. The evaluation criteria are as follows.

(Image quality) A photographic image of a person, a background or the like was printed and visually evaluated. ○: A beautiful image is obtained without beading or ink overflow. B: Some beading and ink overflow. X: Beading and overflow of ink are large, which is not practically sufficient.

(Bleed) Several kinds of character patterns were printed and evaluated visually. ◯: No blank characters or characters with a background are bleeding and sharp. Δ: Characters can be recognized although there is a slight blur in the blank characters and characters with background. X: Blurring is seen even in a single character, which is not practically sufficient.

(Color Gamut Reproduction Range) A color gamut confirmation chart was printed and hue was measured to confirm whether the color gamut reproduction range of offset printing or gravure printing could be covered. A: The color gamut is sufficiently wide, and the color gamut reproduction range of printing is sufficiently satisfied. B: The gamut reproduction range of printing can be satisfied. C: The color gamut is narrow and the gamut reproduction range of printing cannot be satisfied.

(Glossiness) A: The glossiness is larger than 10% and has the glossiness equivalent to that of the coated paper for printing. B: The glossiness is 5 to 10% and the gloss feeling is close to that of coated paper for printing. C: The glossiness is less than 5% and the glossy feeling is the same as that of matte coated paper.

The results are shown in Table 1.

[0045]

[Table 1]

[0046]

INDUSTRIAL APPLICABILITY As described above, the ink jet recording medium according to the present invention has good aesthetics and does not cause bleeding or cockling when recording information such as images and characters with an ink jet printer, and offset printing and gravure printing are performed. It was possible to obtain an inkjet recording medium for print proofing, which can sufficiently satisfy the color gamut reproduction range of printing and has a texture close to that of printing paper.

[0047]

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an inkjet recording medium of the present invention.

[Explanation of symbols]

1 ... Inkjet recording medium 2 ... Ink receiving layer 3 ... Dye fixing layer 4 ... Middle layer 5 ... Support

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Claims (5)

[Claims] 1. An ink jet recording medium comprising an ink receiving layer having an intermediate layer and a dye fixing layer provided on at least one surface of a support made of uncoated paper.
At least silanol-modified polyvinyl alcohols and a filler are used in the intermediate layer, and cationic dry silica having an average particle size of 0.4 μm or less and a binder are used in the dye fixing layer. An inkjet recording medium characterized by the following. 2. The filler for the intermediate layer has an average particle size of 2-5.
The inkjet recording medium according to claim 1, wherein the recording medium is wet silica having a diameter of μm. 3. The ink jet recording medium according to claim 1, wherein the non-coated paper has an air permeability of 300 seconds or less / 100 CC. 4. The ink jet recording according to claim 1, wherein the cationic dry silica in the dye fixing layer is 40 to 120 parts by weight with respect to 10 parts by weight of the binder. Medium. 5. The filler of the intermediate layer is 20 to 5 relative to 10 parts by weight of silanol-modified polyvinyl alcohol.
The recording medium for inkjet according to claim 1, wherein the recording medium is 0 parts by weight.