JP2005169938A - Inkjet recording sheet for printing proofreading - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording sheet similar to a printing sheet in texture and gloss feeling, suitable for printing proofreading and excellent in ink absorbency. <P>SOLUTION: The inkjet recording sheet for printing proofreading, wherein at least one or more layers of an ink receiving layer containing a porous pigment and a gloss developing layer at the topmost layer of the recording sheet overlie a support surface, has an image clarity defined by JIS H 8686 of 15 to 35% and has a 75 degree glossiness defined by JIS P 8142 of 30 to 70%. To further improve appearance evaluation, it is preferable that the lightness index (L<SP>*</SP>) defined by JIS Z 8729 falls within the range of 85≤L<SP>*</SP>≤100, the whiteness degree W represented by a CIE whiteness formula W=2.41L<SP>*</SP>-4.45b<SP>*</SP>[1-0.0090(L<SP>*</SP>-96)]-141.4, is 70≤W≤90, and the tinting index Tw represented by Tw=-1.58a<SP>*</SP>-0.38b<SP>*</SP>, is -2.0≤Tw≤0, according to a measurement method defined by JIS Z 8722. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording sheet that is used for print calibration using an ink jet recording system when printing is performed by a so-called printing machine using printing ink typified by offset printing or the like. More specifically, the present invention relates to an ink jet recording sheet suitable for print proofing and having a texture similar to that of a printing paper to be proofread.

  In recent years, due to advances in ink jet printers and plotters, full-color and high-definition images can be easily obtained.

  The ink jet recording system records images, characters, and the like by causing micro droplets of ink to fly and adhere to a recording sheet such as paper according to various operating principles. Inkjet printers and plotters have rapidly become popular in recent years in various applications as hard copy creation devices for image information such as letters and various graphics created by computers. In particular, color images formed by the multi-color ink jet method can be recorded inferior to multi-color printing by the plate making method and printing by the color photographic method, and in applications where the number of copies is small. Are being widely applied because they are less expensive than printing and photographic techniques.

  In recent years, recording sheets using an ink jet recording method have been increasingly used for print proofing in order to confirm the finished product in advance. In recent printers, products for exclusive use for printing proofreading have also appeared on the market, and it has been desired to commercialize recording paper corresponding to them. Here, it is most important for the ink jet recording sheet used for printing calibration to faithfully reproduce the color and texture of the printing paper.

  Ink jet recording sheets are required to have ink absorptivity, color reproducibility, and the like, and are devised for the pigments, adhesives, and various additives used. As the pigment, a porous synthetic pigment is often used in order to obtain absorbency, and in addition, in order to make the color of the inkjet image clear, the hue is adjusted by bluish and becomes pale. On the other hand, although there is one that defines a perceptual chromaticity index for the color of printing paper that is generally used for printing, it is not a suitable whiteness range for printing calibration paper, and it is not intended to be an inkjet recording for printing calibration. In some cases, the sheet is far from the sheet for use (see, for example, Patent Document 1).

  In addition, fluorescent whitening agents are used for inkjet recording sheets in order to make the color of recorded images clearer. Fluorescent whitening agents improve the whiteness of the appearance by changing the light in the ultraviolet region to light of the blue-violet wavelength and reflecting it. On the other hand, it is also known that the whitening effect is reduced by light irradiation. ing.

  As described above, the fluorescent whitening agent improves the whiteness of the appearance by changing the light of the wavelength in the ultraviolet region to the light of the blue-violet wavelength in the visible region and reflecting it. For this reason, the hue varies depending on the difference in the light source, that is, the intensity of the ultraviolet wavelength contained in the light source. In particular, when a fluorescent brightening agent is used as in an ink jet recording sheet, the apparent hue may differ greatly depending on the light source. Some use two or more colorants and one or more fluorescent brighteners (see, for example, Patent Document 2).

  As described above, in order to use an existing inkjet recording sheet for printing calibration, the brightness and chromaticity of the target printing paper and the recording paper may be greatly different. The difference in texture and texture has become a major problem, and when used for print proofing, the printed finish has not been reproduced.

  Therefore, if an existing inkjet recording sheet is used for print calibration as it is, the difference in glossiness, texture and color difference from the printing paper is large, and it is not suitable for print calibration.

JP 2001-277702 A (page 2-2) JP 2001-205923 A (page 2-2)

  Accordingly, an object of the present invention is to provide an ink jet recording sheet that is similar in texture and gloss to printing paper, is suitable for print calibration, and has excellent ink absorbability.

  As a result of intensive studies on the physical properties of the inkjet recording sheet and the printing paper, the present inventors have invented the printing calibration inkjet recording sheet of the present invention.

  That is, the present inventor has found that the above-described problem is JIS H 8686 in an ink-jet recording sheet for printing calibration in which at least one ink receiving layer is laminated on the surface of the support and a gloss developing layer is laminated on the uppermost layer of the recording sheet. The image stipulation specified in the above is 15 to 35%, and the 75 degree glossiness specified in JIS P 8142 is 30 to 70%. I found it.

Furthermore, the present inventor follows the measuring method defined in JIS Z 8722, the lightness index (L ^* ) defined in JIS Z 8729 is in the range of 85 ≦ L ^* ≦ 100, and the CIE whiteness formula W = 2. 41L ^* −4.45b ^* [1-0.0090 (L ^* −96)] − 141.4 has a whiteness W of 70 ≦ W ≦ 90 and Tw = −1.58a ^* −0.38b ^* It was found that an ink-jet recording sheet for printing proofing having a better appearance can be obtained when the color index Tw indicated by the formula is -2.0 ≦ Tw ≦ 0 (claim 2).

  By adopting such a configuration, it is possible to provide an inkjet recording sheet having inkjet suitability suitable for printing proofreading, with glossiness and texture similar to those of printing paper.

  In the inkjet recording sheet for print proofing according to the present invention, the image clarity defined in JIS H 8686 is preferably 15 to 35, and more preferably 20 to 30. If the image clarity is lower than 15, the printed image lacks visual glossiness and sharpness. If the image clarity is higher than 35%, the printed image has visual glossiness and sharpness. It becomes too high compared with the above, and a glare is generated, which is not preferable.

  The image clarity referred to in the present invention is defined by JIS H 8686, and is measured under the conditions of an incident angle of 60 ° and a comb width of 2 mm.

  Furthermore, it is preferable that 75 degree glossiness prescribed | regulated by JISP8142 is 30 to 70%, More preferably, it is 35 to 55%. If the 75 degree glossiness is lower than 30%, the printed image is insufficient in visual glossiness and sharpness. If the 75 degree glossiness is higher than 70%, a glare feeling is generated compared to the printed paper. It is not preferable.

  In the present invention, in the inkjet recording sheet for printing proof, in which at least one ink-receiving layer containing a porous pigment is laminated on the support surface, and a gloss developing layer is laminated on the uppermost layer of the recording sheet, JIS H The image clarity defined in 8686 is 15 to 35%, and the 75 degree glossiness defined in JIS P 8142 is 30 to 70%, so that the texture and gloss of print paper can be made similar. .

In the present invention, the coating amount of the ink-receiving layer is not particularly limited, but if it is too small, the ink absorbency is good as in the case of the non-coat type ink jet recording sheet, but the image density, color and sharpness are excellent. Low, the ink diffuses in the surface direction of the base paper, and the dot shape deterioration called feathering which is jagged in the shape of a bird feather occurs, and an image of good quality cannot be obtained. If the coating amount is too large, the drying load in the drying process after coating or impregnation increases, and not only the productivity decreases due to the decrease in the coating or impregnation speed, but also the ink acceptance in the case of drying at a high load. Since the binder in the coating composition constituting the layer moves to the surface of the ink receiving layer together with the solvent to evaporate, the amount of voids on the surface is reduced, and therefore, soiling or the like occurs during recording. The range of the coating amount is 10 to 50 g / m ² , more preferably 15 to 30 g / m ² .

As a problem that occurs in an ink receiving layer with a large amount of coating, it is possible to provide a plurality of ink receiving layers according to the required quality, and the coating amount of the ink receiving layer per layer is the coating amount. Although affected by the concentration of the working composition and the ability of the drying process, it is desirably 1 to 20 g / m ^2, more preferably 5 to 15 g / m ² .

In the ink jet recording sheet of the present invention, a gloss developing layer is coated on the ink receiving layer. The range of the coating amount of the glossy layer is 5 to 20 g / m ² , more preferably 10 to 15 g / m ² . When the gloss-expressing layer is dried, it already has gloss, but it is given a moderately high gloss by cast treatment such as supercalender, soft calender, TG calender, etc., gelation method, direct method, riut method, etc. Is possible. More preferably, it is a calendar process. The treatment does not require conditions at high linear pressure and high temperature, and does not reduce the voids in the coating layer to such an extent that the ink absorptivity is deteriorated, so that an ink jet recording sheet meeting the purpose of the present invention can be obtained. .

  The porous pigment contained in the ink receiving layer of the present invention is not limited as long as it can generally absorb ink. In order to obtain a clearer print, it is desirable that the ink absorption rate is higher than that of the upper layer. Therefore, the ink receiving layer preferably has a layer structure containing a pigment. Examples of the pigment include various publicly known pigments in the general coated paper field, such as amorphous silica, kaolin, clay, calcined clay, calcium carbonate, and aluminum hydroxide.

  The porous pigment contained in the glossy layer according to the present invention is preferably colloidal particles that are colloidal by being suspended and dispersed in water such as colloidal silica, boehmite, pseudoboehmite, or other alumina sol or colloidal alumina, More preferably, colloidal silica treated with an organic cation is preferred.

Next, the lightness index (L ^* ) defined by JIS Z 8729 is preferably in the range of 85 ≦ L ^* ≦ 100, more preferably 90 ≦ L ^* ≦ 95. If the lightness index L ^* is lower than 85, the ground color of the recording sheet surface becomes dark and white is insufficient, and if the lightness index L ^* is higher than 100, the ground color of the recording sheet surface becomes bright and white. There is a problem of too much.

The whiteness W shown by the CIE whiteness formula W = 2.41L ^* −4.45b ^* [1-0.0090 (L ^* −96)] − 141.4 is preferably 70 ≦ W ≦ 90, More preferably, 73 ≦ W ≦ 80. When the whiteness W is lower than 70, the recording sheet surface is insufficiently white, and when the whiteness W is higher than 90, the recording sheet surface becomes too white.
Further, the color index Tw indicated by Tw = −1.58a ^* −0.38b ^* is preferably −2.0 ≦ Tw ≦ 0, more preferably −1.5 ≦ Tw ≦ −0.2. It is. If the color index Tw is lower than -2.0, the background color becomes too red or too yellow. If the color index Tw is higher than 0, the background color becomes too green or blue. There is a problem of becoming too much.

  If the whiteness, lightness index, and perceptual chromaticity index are not in the proper ranges, they are not suitable for printing proofreading because they are visually different from the printed paper.

The lightness index lightness index (L ^* ) and perceptual chromaticity index (a ^* , b ^* ) in the present invention are measured in accordance with JIS Z 8722 and the color measurement method and measurement light source defined by JIS Z 8720. This is a value defined by Z 8729. More specifically, the measurement conditions are D-nP (see 6, 3 and 2 in JIS Z 8722), and the light source is a standard light D65.

In the ink jet recording sheet of the present invention, the values of L ^* , a ^* , b ^{* on} the surface of the ink receiving layer are set within the range of the present invention (that is, L ^* , a ^* , b ^* each value is within the scope of claim 2, and in order to contain the L ^* , a ^* , b ^* values of the surface of the ink receiving layer within the scope of claim 2) Alternatively, this is achieved by adding various colorants to at least one of the ink receiving layers. When a colorant is contained in the ink receiving layer, the whiteness and color of the color can be easily controlled, and the effects of the present invention are further enhanced.

  Further, as the colorant in the ink jet recording sheet of the present invention, a dye-based colorant and a pigment-based colorant can be used, but the color tone of the recording sheet is selected from the viewpoint of storage stability. It is particularly preferred to use it.

  Examples of the colorant added include, but are not limited to, titanium black, carbon black, iron black, ivory black, peach black, lamp black, and aniline black. Of these, carbon black is preferred.

  Since the fluorescent whitening agent changes light having a wavelength in the ultraviolet region into visible light, the hue varies depending on the light source irradiated. In particular, in an ink jet recording sheet that uses a large amount of fluorescent brightening agent, the hue often fluctuates greatly as the illumination light source changes. If the hue fluctuation due to the illumination light source is large, the hue will differ greatly from the printing paper to be calibrated, depending on the light source at the place where the finish is confirmed, and fluctuations in the color of the ink jet recording are likely to occur, so accurate calibration is possible. It becomes difficult.

  The ink receiving layer and gloss developing layer used in the present invention are composed of the above-described porous pigment and binder. Examples of the binder include casein, soybean protein, synthetic proteins, starch, cellulose derivatives such as carboxymethylcellulose and methylcellulose, polyvinylpyrrolidone, styrene-acrylic copolymer, styrene-butadiene copolymer, and methylmethacrylate-butadiene copolymer. Can be used for coated papers such as acrylic latexes such as acrylic acid ester, methacrylic acid ester polymer or copolymer, and vinyl latexes such as vinyl acetate and ethylene vinyl acetate copolymer. If it is a binder, it will not specifically limit. Of these, polyvinyl alcohol is preferred.

  Furthermore, as an additive for the ink receiving layer and the gloss developing layer, a dye fixing agent, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a foam suppressing agent, a penetrating agent, an ultraviolet absorber, an antioxidant , Antiseptics, antifungal agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers, and the like can also be included.

  In particular, from secondary amines, tertiary amines, and quaternary ammonium salts that form insoluble salts with sulfonic acid groups, carboxyl groups, amino groups, and the like in water-soluble direct dyes and water-soluble acid dyes that are dye components of water-based inks. When a cationic dye fixing agent is added, the dye is trapped in the ink receiving layer, which prevents the ink from flowing out or oozing out due to water dripping or humidity by improving color and forming an insoluble salt. preferable.

  In the present invention, the method of providing the ink receiving layer and the gloss developing layer may be either an on-machine coater or an off-machine coater. For example, various devices such as conventionally known air knife coaters, curtain coaters, die coaters, blade coaters, gate roll coaters, bar coaters, rod coaters, bill blade coaters, short dwell blade coaters, etc. are used on-machine or off-machine. I can do it.

  Examples of the support used in the present invention include chemical pulps such as LBKP (hardwood bleached kraft pulp), NBKP (softwood bleached kraft pulp), GP (ground pulp), PGW (pressure ground wood), and RMP (refiner mechanical pulp). Wood pulp such as waste paper pulp such as mechanical pulp DIP (deinked pulp) such as TMP (thermomechanical pulp), CTMP (chemical thermomechanical pulp), CMP (chemical mechanical pulp), CGP (chemical ground pulp) The main component is a pigment, a binder, a sizing agent, a fixing agent, a yield improver, a cationizing agent, and a paper strength enhancer. , Base paper manufactured by various devices such as twin wire paper machines, and On paper, starch, sheet and providing a size press or anchor coat layer such as polyvinyl alcohol, art paper provided a coating layer thereon, coated paper, also includes coated paper such as cast-coated paper. Such a base paper and coated paper may be provided with the coating layer according to the present invention as they are, or a calendar device such as a machine calendar, a TG calendar, or a soft calendar may be used for the purpose of controlling smoothing. .

As the basis weight of the support is preferably ^{80g / m 2 ~210g / m 2} . When the basis weight is small, the printed matter causes cockling due to the solvent content of the water-based ink used for the ink jet recording sheet, becomes a wavy state, and cannot withstand printing calibration. Further, when the basis weight is large, the thickness is increased and the texture is different from that of the printing paper, which makes it difficult to perform print calibration.
Example:

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not limited to this. Further, “parts” and “%” shown in the examples represent parts by weight and% by weight unless otherwise specified. Furthermore, unless otherwise specified, the coating amount indicates an absolutely dry coating amount.

<Ink-receiving layer coating solution composition>
The coating composition of the ink receiving layer was 100 parts of synthetic amorphous silica (Silojet P-409: manufactured by Grace Devison) and 40 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.).

<Glossy expression layer coating solution composition>
The coating composition for the glossy layer was composed of 100 parts of colloidal silica (Cab-O-Sperse PG022: manufactured by Cabot Specialty Chemicals Inc.), 5 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.), 5 parts of a cationic dye fixing agent (Unisense CP102: manufactured by Senka Co., Ltd.) was mixed and mixed to obtain a glossy layer coating solution.

<Colorant for ink receiving layer>
Colorant A: TB-786black (manufactured by Dainichi Seika Kogyo Co., Ltd.)
Colorant B: TB-1500 violet (manufactured by Dainichi Seika Kogyo Co., Ltd.)
Colorant C: Kaya Hall HK Liquid (manufactured by Nippon Kayaku).
As shown in Table 1, the colorant shown above was further mixed with the mixture prepared in paragraph 0040 above to obtain an ink-receiving layer coating solution.

^On the surface of the base paper having a basis weight of 104.7 g / m ² , the ink receiving layer coating solution is applied and dried with an air knife coater so that the coating amount on one side becomes 20 g / m ^2, and further, the gloss developing layer coating solution. Was coated and dried with an air knife coater so that the coating amount on one side was 10 g / m ² and calendered with a super calender at a linear pressure of 200 kg / cm to prepare an ink jet recording sheet.

  Ink-jet recording sheet of the present invention is the same as Example 1 except that the inorganic pigment of the glossy layer in Example 1 is 100 parts of acidic colloidal silica (Snowtex PS-MO: manufactured by Nissan Chemical Industries). Got.

Comparative Example 1

  In Example 1, the inkjet recording sheet of the present invention was obtained in the same manner as in Example 1 except that the inorganic pigment of the glossy layer was 100 parts of acidic colloidal silica (Snowtex O: manufactured by Nissan Chemical Industries). It was.

Comparative Example 2

  In Example 1, the inkjet recording sheet of the present invention was prepared in the same manner as Example 1 except that the inorganic pigment of the glossy layer was 100 parts of synthetic amorphous silica (Silojet P405: manufactured by Grace Devison). Obtained.

Comparative Example 3

  In Example 1, 100 parts of fumed alumina (Cab-O-Sperse PG003: manufactured by Cabot Specialty Chemicals, Inc.) was used as the inorganic pigment of the glossy layer, and a gelation method using boric acid as a gelling agent was used. An ink jet recording sheet of the present invention was obtained in the same manner as in Example 1 except that it was pressure-dried on a cast drum at 0 ° C. and cast-treated.

Comparative Example 4

  In Comparative Example 1, an ink jet recording sheet of the present invention was obtained in the same manner as Comparative Example 1 except that the colorant of the ink receiving layer was not used.

Comparative Example 5

  An ink jet recording sheet of the present invention was obtained in the same manner as in Comparative Example 1 except that in Comparative Example 1, 0.1 part of the colorant B in the ink receiving layer was used.

Comparative Example 6

  An ink jet recording sheet of the present invention was obtained in the same manner as in Comparative Example 1 except that the colorant C3 part of the ink receiving layer was used in Comparative Example 1.

1) "Image clarity"
According to the method of JIS H 8686, the image clarity with an incident angle of 60 degrees and a comb width of 2 mm was measured with a image clarity measuring instrument (ICM-1T, manufactured by Suga Test Instruments Co., Ltd.).

2) "75 degree gloss"
The 75-degree glossiness was measured using GM-26D manufactured by Murakami Color Research Laboratory in accordance with JIS Z 8142.

3) “Brightness index and perceived color index”
The lightness index L ^* and the perceptual chromaticity index a ^* and b ^* were measured on the obtained inkjet recording sheet using a spectrophotometer best-eye manufactured by Gretag Macbeth in accordance with JIS Z8722.

4) “CIE whiteness and color index”
The CIE whiteness and color index were calculated by the following formula, measuring the lightness index L ^* and the perceptual chromaticity index a ^* and b ^* .
CIE whiteness W = 2.41L ^* -4.45b ^* [1-0.0090 (L ^* -96)]-141.4
CIE color index Tw = −1.58a ^* −0.38b ^*

5) “Appearance evaluation”
A standard image N1 (portrait) described in JIS X9201 is printed on the obtained ink jet recording sheet using an Epson ink jet plotter (PM-9000C) and a BEST software RIP (BESTPROOF), and looks as a printed matter. Was comprehensively evaluated. In the evaluation, the evaluation was made by comparing with the target printing paper printed by offset printing. Evaluations were given as ◎ for those with very little sensory difference, ◯ for those that were accepted sensuously with little discomfort, △ for those with a slightly uncomfortable feeling, and × for those with a very strong difference.

From Table 1 and Table 2, Examples 1 and 2 are 15 to 35% of the image clarity defined in JIS H 8686 as an inkjet recording sheet for print proofing, and 75 degree glossiness defined in JIS P 8142. 30 to 70%, and according to the measurement method specified in JIS Z 8722, the lightness index (L ^* ) specified in JIS Z 8729 is in the range of 85 ≦ L ^* ≦ 100, and CIE whiteness W = 2.41L ^* −4.45b ^* [1−0.0090 (L ^* −96)] − 141.4 The whiteness W measured and calculated by the formula of 14 ≦ W ≦ 90 and Tw = −1.58a ^Since the color index Tw measured and calculated by the formula of −0.38b ^* is −2.0 ≦ Tw ≦ 0, it is preferable as an inkjet recording sheet for printing proofreading. Comparative Examples 1 to 6 deviate from the above conditions. As a result, Comparative Examples 1 to 6 are significantly different in image clarity and 75 degree glossiness from those of Examples, and compared with those printed by offset printing in appearance evaluation. Thus, the sensory difference is felt very strongly, the appearance evaluation is remarkably bad, and it is still unsuitable as an ink jet recording sheet for printing proofreading.

Claims (2)

An ink jet recording sheet for printing proofing in which at least one ink receiving layer containing a porous pigment and a glossy expression layer are laminated on the uppermost layer of the recording sheet are defined in JIS H 8686. The above-described inkjet recording sheet for printing proof, wherein the image clarity is 15 to 35%, and the 75 degree glossiness defined in JIS P 8142 is 30 to 70%. The lightness index (L ^* ) defined by JIS Z 8729, measured according to the measurement method defined by JIS Z 8722, is in the range of 85 ≦ L ^* ≦ 100, and the CIE whiteness formula W = 2.41 L ^* −. 4.45b ^* [1-0.0090 (L ^* −96)] − 141.4 indicates a whiteness W of 70 ≦ W ≦ 90 and Tw = −1.58a ^* −0.38b ^*. The inkjet recording sheet for printing proofreading according to claim 1, wherein the color index Tw is −2.0 ≦ Tw ≦ 0.