JP2000006515A - Ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording paper which is of the so-called plain paper type with no pigment coated on a recording face and shows the outstanding image density of a recorded image and chromatic reproducibility and also has a printing part with high water resistance and face strength. SOLUTION: This ink jet recording paper has an applied coating solution composed mainly of a neutral base paper made of wood pulp as a main raw material, a fluorescent brightener, a dye/pigment, a water-soluble binder and a cationic polymer fixing agent. In addition, the recording paper shows 95% or more ISO whiteness degree of a coated paper measured by a measurement method prescribed by JIS P-8148 using a xenon flash lamp as a light source and 7-15% fluorescent intensity. Further, the recording paper is manufactured through a paper-making process using calcium carbonate as a filler and contains 5-20% base paper ash by a specific treatment. Besides, the recording paper has a specific mixing ratio of a specific fluorescent brightener to a specific cationic polymer fixing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording paper for recording in color using a water-soluble ink. More specifically, the present invention relates to a so-called plain paper type ink jet recording paper in which a recording surface is not coated with a pigment, and in particular, by increasing the ISO whiteness of the paper by using a fluorescent whitening agent, the The present invention relates to an ink jet recording paper which is excellent in image density and color reproducibility, and further excellent in water resistance and surface strength of a printed portion.

[0002]

2. Description of the Related Art An ink jet recording apparatus is a method in which ink is directly ejected onto a recording sheet, and has attracted attention as a recording method which has a lower running cost than conventional recording apparatuses, is quiet, and allows easy color recording. . Ink used in such a recording method is water-based ink in terms of safety and printing characteristics.In addition, recording paper absorbs ink quickly and ink overflows even if different color inks overlap. That the ink dots are not spread properly, that the dot shape is close to a perfect circle, that the dot edges are clear, that the dot density is high, and that the dot contrast is high in color printing. It is required that the ISO whiteness is sufficiently high to make the image stand out.

As the recording paper used in the above-mentioned ink jet recording apparatus, Japanese Patent Application Laid-Open No. 59-35977 and Japanese Patent Application Laid-Open No.
It has been proposed to use a special coated paper as disclosed in JP-A-135682. On the other hand, in the field of monochrome recording and business color recording, it is desired to use low-priced and versatile recording paper, that is, plain paper generally used in the field of electrophotographic recording apparatuses.

In recent years, when a neutral toner transfer sheet, which is becoming mainstream as a recording sheet for use in an electrophotographic recording apparatus, is used as a recording sheet of an ink jet recording method, a filler used for a base sheet can be limited, and a full-color recording medium can be used. Compared with the inkjet-only coated paper, paper with high color reproducibility and high ISO whiteness in color printing could not be obtained. Furthermore, the so-called plain paper type ink jet recording paper, which has not been coated with a pigment on the recording surface, which has been proposed so far, focuses on the fact that ink jet recording is possible. As for the water resistance, which has not been solved yet.

[0005]

An object of the present invention is to improve the conventional problems in the above technical field. The present invention relates to a so-called plain paper type color ink jet recording paper in which a recording surface is not coated with a pigment, and is excellent in surface strength, particularly excellent in water resistance of a recorded image and by increasing ISO whiteness. Another object of the present invention is to provide an ink jet recording sheet excellent in image density of a recorded image and color reproducibility.

[0006]

The above object is achieved by the present invention described below.

That is, the ink jet recording paper according to the first invention comprises a neutral base paper mainly made of wood pulp and a fluorescent whitening agent, a dye / pigment, a water-soluble binder and a cationic polymer fixing agent as main components. It is an inkjet recording paper coated with a coating liquid, and uses a xenon flash lamp of the coated paper as a light source according to JIS P-
It is characterized in that the ISO whiteness measured by the measuring method specified in 8148 is 95% or more and the fluorescence intensity is 7 to 15%.

[0008] The ink jet recording paper according to the second invention is the same as the first invention, wherein the neutral base paper is made using calcium carbonate as a filler and subjected to incineration treatment at 500 ° C.
Except for the time, the base paper ash content according to JIS P-8126 is 5 to 20%.

The ink jet recording paper according to a third aspect of the present invention is the ink jet recording paper according to the first aspect, wherein the fluorescent whitening agent of the coating solution is a diaminostilbene-disulfonate derivative (A) and the cationic polymer fixing agent is It is a polyvinyl alcohol-cation monomer graft polymer (B), wherein the mixing ratio A: B of the solid coating amount is 1: 6 to 2: 3.

Further, in the ink jet recording paper according to the first to third aspects, the coating liquid is preferably applied by using an on-machine size press of a paper machine.

Further, in the ink jet recording paper according to the first to fourth aspects of the present invention, preferably, the wood pulp contains waste paper pulp.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the ink jet recording paper of the present invention will be described in detail.

The present inventors first examined the relationship between the ISO whiteness of the ink jet recording paper of the present invention and the printing characteristics of the ink jet recording apparatus.

The plain paper type ink jet recording paper does not have an ink absorbing layer unlike the so-called coated paper type, so that the base paper is used as the ink absorbing layer. Therefore, the whiteness of the base paper affects the printing characteristics of the ink jet recording paper. The whiter the base paper, the higher the contrast of the printed matter, the higher the print quality.

However, since the Hunter whiteness defined in JIS P-8123 has been established so far, the whiteness of the sample containing the fluorescent whitening agent and the whiteness of the visual appearance often do not match. This is because in Hunter whiteness, the illumination light illuminates the filament-type lamp with light that has passed through a blue filter, and the light in the wavelength region that excites the fluorescent whitening agent (mainly light in the ultraviolet region) is greatly increased. It is considered that there was a cause for being cut. In ISO whiteness, white light from an illumination light source is diffusely illuminated using an integrating sphere. If a xenon flash lamp is used as the illumination light source, light in a wavelength region for exciting the fluorescent whitening agent is included, so that a numerical expression close to luminous whiteness is possible.

ISO of ink jet recording paper of the present invention
As a result of comparing and examining the relationship between the whiteness and the printing characteristics of the ink jet recording apparatus, a good correlation was found between the ISO whiteness of the sample and the printing characteristics, particularly, the image density after printing and the image reproducibility. Was done. Then, when the ISO whiteness of the recording paper used in the ink jet recording apparatus is 95% or more, it is found that the image density when printed by the ink jet recording apparatus and the balance of image reproducibility are good. Invented paper.

In order to improve the visual whiteness alone, the pulp fiber is given a bluish purple color, which is a yellow color, by bluing the sample, which has been conventionally widely used.
The remaining yellow was canceled out to make it more achromatic, and in some cases even more bluish, giving the illusion that the whiteness was improved, but there was a problem that the brightness was considerably reduced .

In order to improve the printing characteristics of the ink jet recording paper, it is necessary to increase the ISO whiteness to 95 using a fluorescent whitening agent.
%. The fluorescent whitening agent on the pulp fiber absorbs ultraviolet light in daylight and is 400 to 500 nm.
As a result, the reflected light on the short wavelength side of the visible portion is replenished, and the bluish tint is performed without a decrease in lightness. As a result, the whiteness appears to be further improved to the naked eye. Therefore, brightening with a fluorescent brightener is different from bleaching, which chemically removes coloring substances and stains from materials. As a result, a remarkable whitening effect that cannot be achieved in the bleaching step can be obtained.

In a color ink jet recording paper, if the ISO whiteness is less than 95%, the luminous whiteness is insufficient and the print quality is poor with poor image reproducibility. Therefore,
Considering the printing characteristics of the ink jet recording paper and the whiteness upon printing, the ISO whiteness is desirably 95% or more.

As a method for improving the ISO whiteness, a material having a high whiteness is selected as a raw material for papermaking, and a fluorescent whitening agent can be applied from the above mechanism. The effect is recognized when the blending amount of the fluorescent whitening agent is large, but the effect gradually becomes saturated, eventually causing a phenomenon called overdyeing, and conversely, the whiteness decreases.
In the present invention, it is preferable to express by fluorescence intensity other than ISO whiteness. The fluorescence intensity is expressed as a difference between whiteness measured with illumination light including light in the ultraviolet region and whiteness measured with illumination light obtained by cutting light in the ultraviolet region with a UV filter, and is 7 to 15% in the present invention. Is preferably within the range. If it is less than 7%, the whiteness is obviously weak,
Above 15%, the fluorescence is clearly saturated, and is not economically optimal.

Secondly, in the present invention, it is preferable to use calcium carbonate used in neutral paper as a filler used when making base paper, since it can increase ISO whiteness. Further, as the ink jet recording paper, it is preferable to use calcium carbonate from the viewpoint of increasing the ink absorbency and the image density. Calcium carbonate has high whiteness and high ink absorbency among fillers that can be used for neutral base paper. Furthermore, except that the incineration treatment was performed at 500 ° C. for 4 hours, JISP-81 was used.
The ash content according to No. 28 is desirably 5 to 20%.
If the ash content of the paper is less than 5%, the suitability for ink jet recording is deteriorated in terms of ISO whiteness and opacity. On the other hand, when the ash content is 20% or more, plain paper type paper is used for various purposes as office paper. Conversely, an increase in the ash content tends to cause the problem of paper dust from the edge of the recording paper and Problems such as easy generation of paper dust due to a decrease in surface strength during printing occur.

The internal sizing agent used for making the base paper of the present invention includes a neutral rosin sizing agent, an alkenyl succinic anhydride, an alkyl ketene dimer, a petroleum resin sizing agent and the like used for neutral papermaking. However, it is desirable to use a neutral rosin sizing agent as an ink jet recording paper, as it has a uniform size effect even at a low size, as a measure against strike-through. Alkenyl succinic anhydride, alkyl ketene dimer, etc., which are internal sizing agents generally used for neutral papermaking, require a small amount of addition due to their high sizing effect. Since it is inferior to a neutral rosin sizing agent in terms of imparting sizing properties, it is not suitable as an internal sizing agent for inkjet recording paper. Also, even when diverted as recording paper used in an electrophotographic transfer recording device,
It is desirable to use a neutral rosin sizing agent from the viewpoint of transportability.

[0023] In the paper stock, various anionic, nonionic, cationic or amphoteric paper strength improvers which have been conventionally used may be used as long as the desired effects of the present invention are not impaired. An internal additive for papermaking is appropriately selected and used as needed. For example, various types of starch, polyacrylamide, polyethyleneimine, polyamine, polyamide / polyamine, urea formalin resin, melamine formalin resin, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, and one of polyamide resins
Species or two or more kinds are used in appropriate combination.

Incidentally, it is also possible to appropriately add an internal additive for papermaking such as a dye, a fluorescent brightener, a pH adjuster, a defoamer, a pitch control agent and a slime control agent according to the purpose.

In the papermaking method of the present invention, a paper machine known in the papermaking industry such as a fourdrinier paper machine, a twin-wire paper machine, a combination paper machine, a round mesh paper machine, and a Yankee paper machine can be used as appropriate.

Third, the most significant feature of the present invention is that the above-mentioned base paper is coated with a coating liquid containing a fluorescent whitening agent, a dye / pigment, a water-soluble binder and a cationic polymer fixing agent as main components. It is characterized by being an ink jet recording paper. By applying a water-soluble binder to the base paper, the strength of the base paper surface can be improved. Also,
Cationic polymer fixing agents, as recording paper used in ink jet recording devices, generally have an anionic group to impart water solubility, improve the fixability of the ink, and improve the water resistance of the printed image. Can be provided.

However, the cationic polymer fixing agent, when the main focus is only on the fixability of the ink, as a result of increasing the cation strength, decreases the intensity of the fluorescent whitening agent which is another feature of the present invention. It will be. The present inventors have conducted intensive studies on the relationship between the fixability of the ink and the decrease in the intensity of the fluorescent whitening agent for the cationic polymer fixing agent. As a result, the fluorescent whitening agent was found to be a diaminostilbene-disulfonate derivative (A ) And the cationic polymer fixing agent is a polyvinyl alcohol-cationic monomer graft polymer (B), and the two are mixed in a solid coating amount A:
By combining B in the range of 1: 6 to 2: 3,
The inventors have found that both the development of the ISO whiteness and the water resistance of the ink-jet printed portion are compatible, and the present invention has been accomplished. If the ratio of the fluorescent whitening agent is less than 1: 6, the ISO whiteness decreases, and if it exceeds 2: 3, the water resistance of the printed ink-jet printed portion is greatly deteriorated.

As the cationic polymer fixing agent in the present invention, a dye component of the aqueous ink is used in order to impart water resistance for suppressing the flow or bleeding of the ink due to dropping of water or moisture absorption on the recording paper. A primary to tertiary amine which forms an insoluble salt with a sulfonic acid group, a carboxyl group or an amino group in a water-soluble direct dye or a water-soluble acid dye, or
A quaternary ammonium salt monomer, oligomer, or polymer can be used. Specifically, it is possible to add dimethylamine / epichlorohydrin condensate, acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dimethyl / diallylammonium chloride, polyvinyl alcohol-cation monomer graft polymer and the like. However, when a polyvinyl alcohol-cation monomer graft polymer is used, the most effective effect can be obtained.

The fluorescent whitening agent of the present invention absorbs ultraviolet rays in daylight and replenishes the reflected light on the short wavelength side of the visible region, so that it only has a bluish color without lowering the brightness. In addition, it is necessary to be excellent in light resistance, solubility, dyeing property and the like. Specifically, a diaminostilbene-disulfonate derivative, an oxazole derivative, a biphenyl derivative, an imidazole derivative, a coumarin derivative, and a pyrazoline derivative are used, but an effect is obtained when a diaminostilbene-disulfonate derivative is used for pulp fibers. Is most favorable.

The water-soluble binder used here is:
For example, polyvinyl alcohol, silanol-modified polyvinyl alcohol, vinyl acetate, oxidized starch, phosphorylated esterified starch, etherified starch, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, casein, gelatin, soybean protein, silyl-modified polyvinyl alcohol, etc .; Maleic resin, styrene-
Conjugated diene copolymer latex such as butadiene copolymer, methyl methacrylate-butadiene copolymer; polymer or copolymer of acrylic acid ester and methacrylic acid ester; polymer or copolymer of acrylic acid and methacrylic acid; Acrylic polymer latex;
Vinyl-based polymer latex such as ethylene-vinyl acetate copolymer; or functional group-modified polymer latex with functional group-containing monomer such as carboxyl group of these various polymers; Thermosetting synthetic resin such as melamine resin and urea resin Aqueous adhesives such as polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin. In addition, the use of a known natural or synthetic resin adhesive is not particularly limited.

The coating liquid of the present invention may contain one or more coloring dyes and coloring pigments in combination with an optical brightener as an additive. The coloring dye and the coloring pigment can be used alone or in combination, but for the purpose of the present invention, it is preferable to use a bluing agent that subtracts a yellow portion of 580 to 600 nm. Coloring dyes used here,
The type of the coloring pigment is not particularly limited as long as it is a commonly used dye pigment, but more preferably, it is anionic colored from the viewpoint of compatibility with a water-soluble binder, light resistance, and uniform color development at the time of coating. Pigments such as dioxazine pigments and phthalocyanine pigments are preferred.

Further, other additives include a surface sizing agent, a pH regulator, a thickener, a flow improver, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, a penetrating agent, a coloring dye, and coloring. Pigments,
Fluorescent whitening agents, ultraviolet absorbers, preservatives, fungicides, antioxidants, inorganic conductive agents such as sodium chloride and potassium chloride,
It is of course possible to appropriately mix an organic conductive agent and the like.

Examples of the apparatus for applying a coating solution containing the above-described fluorescent whitening agent, dye / pigment, water-soluble binder and cationic polymer fixing agent as main components by a size press in the present invention include a conventional size press, A gate roll size press, a film transfer type size press, a rod coater, a bill blade, a short dwell coater, or the like can be used. Among these coating devices, it is desirable to use a system in which a fluorescent whitening agent and a dye / pigment can be uniformly applied to a paper layer on-machine,
An on-machine size press is preferred. After coating, if necessary, machine calendar, heat calendar,
It is also possible to finish using a calendar device such as a super calendar or a soft calendar.

The coating amount in the present invention is not particularly limited.
Although the coating depends on the size of the base paper, it is desirable to apply about 1 to 3 g / m ² as a solid content of the coating liquid to the base paper.

The wood pulp used for making the base paper of the present invention includes NBKPLBKP, NBS
In addition to P, LBSP, GP, TMP and the like, waste paper pulp may be mentioned. In use, they are mixed and used at a ratio according to several purposes.

The raw materials for waste paper pulp referred to in the present invention include: top white, ruled white, cream white, card, and the like shown in the waste paper standard quality standard table of the Waste Paper Recycling Promotion Center.
Special white, medium white, imitation, fair white, Kent, white art, special top cut,
Another example is newspaper, magazine, etc. Further specific examples include non-coated computer recording paper that is information-related recording paper, printer recording paper such as thermal paper and pressure-sensitive paper, and OA waste paper such as PPC recording paper, art paper, coated paper, lightly coated paper, Coated paper such as matte paper, or high-quality paper, high-quality color paper, notebooks, stationery, wrapping paper, fancy paper, medium-sized paper, newsprint, paper changing, super-hanging paper, imitation paper, pure white roll paper, milk carton, etc. As used paper such as uncoated paper and paperboard, chemical pulp paper, high-yield pulp-containing paper, and the like are used, but are not particularly limited to printing, copying, printing, and non-printing.

The ink jet recording paper of the present invention can be used not only as an ink jet recording paper but also as an office paper as an electrophotographic transfer paper, a thermal transfer image receiving paper, or a printing paper.

[0038]

The present invention will be described in detail below with reference to examples. Note that the present invention is not limited to this. All parts and percentages in the following are by weight.

Examples 1 to 10 and Comparative Examples 1 to 8 First, base papers 1 to 6 were prepared according to the following composition.

<Base paper composition 1> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (manufactured by Okutama Industry Co., Ltd .; TP-121) 20 parts Neutral rosin sizing agent (Nippon PMC) 0.4 parts Aluminum sulfate 1.4 parts Amphoteric starch (manufactured by NSC Japan Ltd .; Cato3210) 1.0 part Dye (Bassasol Violet 57L; manufactured by BASF) 0.00096 parts Retention improver (Allite) 0.025 parts by a Koroit Co., Ltd .; Percoll 57) Retention agent (Alight Coroit Co .; Organozobe O) 0.1 part

<Base paper composition 2> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (Okutama Kogyo Co .; TP-121) 10 parts Neutral rosin sizing agent (Nippon PMC) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0.02 parts Amphoteric starch (Nippon NSC; Cato3210) 1.0 parts Dye (Bazsa) Sole Violet 57L; BASF Co., Ltd. 0.00096 Yield improver (Alight Coroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co .; Organozob O) 0.1 part

<Base paper composition 3> Base paper composition; high-white LBKP for photographic base paper (freeness; 450 ml, csf) 100 parts Talc (Kamitalc Co .; B talc) 6 parts Rosin sizing agent (Harima Chemical Co., Ltd., Hersize) L-750) 0.3 parts Aluminum sulfate 1.5 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keiko BUL) 0.02 parts Cationic starch (manufactured by NSC Japan; Cato304) 0.3 parts Dye (Passa violet) 57 L; manufactured by BASF) 0.00096 parts Yield improver (manufactured by Hymo; high holder 301) 0.03 part

<Base paper composition 4> Base paper composition; high-white LBKP for photographic base paper (freeness: 450 ml, csf) 100 parts Talc (Kamitarku Co., Ltd .; B talc) 10 parts Rosin sizing agent (Harima Chemical Co., Ltd., Hersize) L-750) 0.3 parts Aluminum sulfate 1.5 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keiko BUL) 0.02 parts Cationic starch (manufactured by NSC Japan; Cato304) 0.3 parts Dye (Passa violet) 57 L; manufactured by BASF) 0.00096 parts Yield improver (manufactured by Hymo; high holder 301) 0.03 part

<Base paper composition 5> Base paper composition; high-white LBKP for photographic base paper (freeness; 450 ml, csf) 100 parts Talc (Kamitalc Co .; B talc) 15 parts Rosin sizing agent (Harima Chemical Co., Ltd., Hersize) L-750) 0.3 parts Aluminum sulfate 1.5 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keiko BUL) 0.02 parts Cationic starch (manufactured by NSC Japan; Cato304) 0.3 parts Dye (Passa violet) 57 L; manufactured by BASF) 0.00096 parts Yield improver (manufactured by Hymo; high holder 301) 0.03 part

<Base paper formulation 6> Base paper formulation: LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (TP-121 manufactured by Okutama Industry Co., Ltd.) 20 parts Neutral rosin sizing agent (PMC Japan) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keiko BUL) 1.0 part Amphoteric starch (Nippon NSC; Cato 3210) 1.0 parts Dye Sole Violet 57L; BASF Co., Ltd. 0.00096 Yield improver (Alight Coroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co .; Organozob O) 0.1 part

<Base paper composition 7> Base paper composition; LBKP (freeness: 450 ml, csf) 80 parts Base paper composition; DIP (freeness: 400 ml, csf) 20 parts Calcium carbonate (Okutama) Industrial Co., Ltd .; TP-121) 10 parts Neutral rosin sizing agent (Nippon PMC; CC-167) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0. 02 parts Amphoteric starch (manufactured by NSC Japan Ltd .; Cato3210) 1.0 part Dye (Passasol Violet 57L; manufactured by BASF) 0.00096 parts Yield improver (Allite Koroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co., Ltd .; Organosorb O) 0.1 parts

A 0.3% slurry of the above composition was mixed with a milling width of 1,3.
00 mm, papermaking speed 150 m / min. A base paper having a basis weight of 78.4 g / m ² and a water content of 5.0% was produced by a Fourdrinier paper machine, and this was used as a base paper for size press.

Next, ink jet recording papers of Examples and Comparative Examples were prepared according to the following method.

Example 1 The base paper 2 produced as described above was subjected to size press with the following composition to obtain an ink jet recording sheet having a solid content of 3.0 g / m ² , which was used as the ink jet recording sheet of Example 1. The ash content of the base paper 2 was 8.9%. <Composition of size press liquid 1> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Co .; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.5 parts Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB536 blue) 0.004 parts Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB1548 violet) 0.003 parts Water 93.393 parts

Example 2 An ink jet recording sheet of Example 2 was prepared in the same manner as in Example 1 except that 1 composition of the size press liquid was used and 2 compositions of the size press liquid were used. <Composition of size press liquid 2> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Corporation; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 1.0 part Cationic surface size agent (manufactured by BASF; Bathlast 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB1548 violet) 0.003 parts water 92.893 parts

Example 3 An ink jet recording sheet of Example 3 was prepared in the same manner as in Example 1 except that 1 composition of the size press liquid was used and 3 compositions of the size press liquid were used. <Composition of size press liquid 3> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Hymo Corporation; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 1.5 parts Cationic surface size agent (manufactured by BASF; Bathlast 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 parts Water 92.393 parts

Example 4 An ink jet recording sheet of Example 4 was prepared in the same manner as in Example 1 except that 1 composition of the size press liquid was used and 4 compositions of the size press liquid were used. <Composition of size press liquid 4> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 2.0 parts Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 parts water 91.893 parts

Example 5 An ink jet recording sheet of Example 5 was produced in the same manner as in Example 1, except that the base paper 2 was used as the base paper 1. The ash content of the base paper 1 was 17.3%.

Example 6 An ink jet recording paper of Example 6 was produced in the same manner as in Example 1 except that 1 composition of the size press liquid was changed to 5 compositions of the size press liquid. <Composition of 5 size press liquids> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Co .; SC-600G2) 0.75 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol) (BRAL) 0.25 parts Cationic surface size agent (manufactured by BASF; Bathlast 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo; TB1548) (Violet) 0.003 parts Water 95.893 parts

Example 7 An ink jet recording sheet of Example 7 was produced in the same manner except that the base paper 2 used in Example 4 was changed to the base paper 6. The ash content of the base paper 6 was 17.5%.

Example 8 An ink jet recording sheet of Example 8 was produced in the same manner except that the base paper 2 used in Example 1 was used as the base paper 7. The ash content of the base paper 1 was 9.3%.

Example 9 An ink jet recording sheet of Example 9 was produced in the same manner as in Example 1 except that 1 composition of the size press liquid was changed to 6 compositions of the size press liquid. <Composition of size press liquid 6> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Hymo Corporation; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.5 parts Cationic surface size agent (manufactured by BASF; Bathlast 265D) 0.1 part Dye (manufactured by Sumitomo Chemical Co., Ltd .; Sumilite Supra Blue) 0.002 part Dye (manufactured by Sumitomo Chemical Co., Ltd .; Sumilite Spraviolette) 0.003 parts Water 93.395 parts

Example 10 An ink jet recording sheet of Example 10 was prepared in the same manner as in Example 1 except that 1 composition of the size press liquid was changed to 7 compositions of the size press liquid. <Composition of size press solution 7> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Co., SC-600G2) 3 parts Fluorescent whitening agent (commercially available triazole derivative) 1.0 part 0.1 parts of cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.14 coloring pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 parts coloring pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 part 92.893 parts of water

COMPARATIVE EXAMPLE 1 The base paper 3 prepared above was subjected to size press with one composition of a size press liquid to obtain an ink jet recording sheet having a solid content of 3.0 g / m ^2. And The ash content of the base paper 3 was 5.9%.

Comparative Example 2 An ink jet recording paper of Comparative Example 2 was produced in the same manner except that the raw paper 3 used in Comparative Example 1 was changed to the raw paper 4. The ash content of the base paper 4 was 9.3%.

Comparative Example 3 An ink jet recording paper of Comparative Example 3 was prepared in the same manner except that the raw paper 3 used in Comparative Example 1 was used as the raw paper 5. The ash content of the base paper 5 was 13.0%.

Comparative Example 4 An ink jet recording paper of Comparative Example 4 was prepared in the same manner as in Example 1 except that 1 composition of the size press liquid was used and 8 compositions of the size press liquid were used. <Composition of size press liquid 8> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3.5 parts Cationic polymer fixing agent (manufactured by Himo Co., SC-600G2) 3 parts Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Colored pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 parts Colored pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 parts Water 93.393 parts

Comparative Example 5 An ink jet recording sheet of Comparative Example 5 was produced in the same manner as in Comparative Example 4, except that the base paper 2 was used as the base paper 1.

Comparative Example 6 An ink jet recording sheet of Comparative Example 6 was obtained by subjecting the base paper 2 produced above to a size press with the following composition to obtain an ink jet recording sheet having a solid content of 3.0 g / m ² . <Combined size press solution 9> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 6 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keiko BRAL) 0.5 part .1 part Colored pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Colored pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 part Water 93.393 parts

Comparative Example 7 Hewlett-Packard's "B" commercially available in the United States
right White "was purchased to make Comparative Example 7.

Comparative Example 8 A comparative example 8 was obtained by purchasing "PB paper" which is a commercially available paper for electrophotography and ink jet from Canon Inc. in Japan.

The recording papers of Examples 1 to 10 and Comparative Examples 1 to 8 produced as described above were measured for ISO whiteness and fluorescence intensity by the evaluation methods described below. Table 1 shows the results.

1) ISO whiteness The sample was humidified in an environment of 20 ° C. and 65% RH for 24 hours, and a PF manufactured by Nippon Denshoku Industries Co., Ltd. using a xenon flash lamp as a light source in accordance with JIS P-8148.
ISO whiteness was measured using -10. Measurement is 10
The test was performed using a single test piece, and the average value of the front and back surfaces of the test piece was defined as ISO whiteness. In a full-color printing, when outstanding whiteness is required, the ISO whiteness is preferably 95% or more.

2) Fluorescence Intensity The measurement sample was humidified in an environment of 20 ° C. and 65% RH for 24 hours, and then a PF manufactured by Nippon Denshoku Industries Co., Ltd. using a xenon flash lamp as a light source according to JIS P-8148.
Using -10, ISO whiteness was measured with and without a UV cut filter. The fluorescence intensity is U
It is expressed as a difference between the ISO whiteness without using the V cut filter and the ISO whiteness when the UV cut filter is used. The measurement was performed using ten test pieces, and the average value of the front and back surfaces of the test pieces was defined as the fluorescence intensity. For paper used in daily life, the fluorescence intensity is 7 to 15
%.

The suitability for ink jet was evaluated by the evaluation method described below. Table 1 shows the results.

1) Water resistance of images Characters and ruled lines were printed with an ink jet printer BJ-420J manufactured by Canon Inc., and distilled water was applied to the printed portions. One drop was dropped with 15 injection needles, and after standing to dry, the degree of bleeding was visually evaluated. In addition, A:
Good characteristics, B: good in practically acceptable range, C: practical problem, D: poor characteristics.

2) Print density Canon inkjet printer BJ-420J
Was used to print a black solid pattern, and after standing to dry, the optical density was measured with a Macbeth densitometer. As a criterion for evaluation, a concentration of 1.2 or more is preferable in practical use.

3) Image Reproducibility Inkjet Printer BJ-420J manufactured by Canon Inc.
Prints N1 and N4 images of high-definition digital standard image data conforming to JIS X-9201 issued by the Japanese Standards Association, and after leaving to dry, determine the difference in hue value between the print sample and the attached print sample. evaluated. Note that N
In No. 1, the change in the skin color of the highlight portion of the woman's face and palm and the color balance in a grayish background were compared with N4.
The evaluation focused on the tone of the bright part and the reproducibility of neutral colors in metal tableware and glass. As evaluation criteria, A: good characteristics, B: good in practically acceptable range, C: practical problem, D: poor characteristics.

[0074]

[Table 1]

Considering the above evaluation results, Examples 1 to
As is clear from FIG. 6, in order to obtain good print density and image reproducibility, it is necessary that the ISO whiteness is 95% or more and the fluorescence intensity is 7% or more. In addition, it can be seen from Example 7 that the image density and image reproducibility are saturated even when the fluorescence intensity is increased to nearly 15%. In Example 9, it can be seen that not only pigments but also dyes can be used as colorants in the size press composition, and that various types of fluorescent whitening agents can be used. As is apparent from Comparative Examples 1 to 5, it is also found that the image reproducibility is deteriorated only when the characteristics of the ISO whiteness and the fluorescence intensity do not meet either of the standards. Further, as shown in Comparative Example 6, when the cationic fixing agent is not applied, the water resistance is greatly deteriorated.

Examples 11 to 15 For the purpose of clarifying the features of the second invention by the combination, base papers 8 to 12 were prepared according to the following composition. <Base paper composition 8> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (Okutama Kogyo; TP-121) 26 parts Neutral rosin sizing agent (Nippon PMC; CC) -167) 0.4 part Aluminum sulfate 1.4 part Amphoteric starch (manufactured by NSC Japan Ltd .; Cato3210) 1 part Dye (hasasole violet 57L; manufactured by BASF) 0.00096 parts Retention improver (manufactured by Alite Coroit); Percoll 57) 0.025 part Yield improver (manufactured by Alite Coroit Co., Ltd .; Organosorb O) 0.1 part

<Base paper composition 9> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (TP-121 manufactured by Okutama Industry Co., Ltd.) 32 parts Neutral rosin sizing agent (PMC Japan) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0.02 parts Amphoteric starch (Nippon NSC; Cato3210) 1.0 parts Dye (Bazsa) Sole Violet 57L; BASF Co., Ltd. 0.00096 parts Retention improver (Alight Coroit Co., Ltd .; Percoll 57) 0.030 parts Yield improver (Alite Coroit Co., Ltd .; Organosove O) 0.15 part

<Base paper composition 10> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (TP-121 manufactured by Okutama Industry Co., Ltd.) 21 parts Neutral rosin sizing agent (PMC Japan) 0.4 parts Aluminum sulfate 1.4 parts Amphoteric starch (manufactured by NSC Japan Ltd .; Cato3210) 1.0 part Dye (Bassasol Violet 57L; manufactured by BASF) 0.00096 parts Retention improver (Allite) 0.025 parts by a Koroit Co., Ltd .; Percoll 57) Retention agent (Alight Coroit Co .; Organozobe O) 0.1 part

<Base paper composition 11> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (manufactured by Okutama Industry Co., Ltd .; TP-121) 11 parts Neutral rosin sizing agent (Nippon PMC) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0.02 parts Amphoteric starch (Nippon NSC; Cato3210) 1.0 parts Dye (Bazsa) Sole Violet 57L; BASF Co., Ltd. 0.00096 Yield improver (Alight Coroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co .; Organozob O) 0.1 part

<Base paper composition 12> Base paper composition; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (TP-121 manufactured by Okutama Industry Co., Ltd.) 6 parts Neutral rosin sizing agent (PMC Japan) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0.02 parts Amphoteric starch (Nippon NSC; Cato3210) 1.0 parts Dye (Bazsa) Sole Violet 57L; BASF Co., Ltd. 0.00096 Yield improver (Alight Coroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co .; Organozob O) 0.1 part

A 0.3% slurry having the above composition was mixed with a milling width of 1,3.
00 mm, papermaking speed 150 m / min. A base paper having a basis weight of 78.4 g / m ² and a water content of 5.0% was produced by a Fourdrinier paper machine, and this was used as a base paper for size press.

Next, the ink jet recording paper of the example was produced according to the following method.

Example 11 The base paper 11 prepared as described above was subjected to size press with one composition of a size press liquid to obtain an ink jet recording sheet having a solid content of 3.0 g / m ^2. did. The ash content of the base paper 11 was 8.9%.

Example 12 An ink jet recording paper of Example 12 was produced in the same manner as in Example 11, except that the base paper 11 used in Example 11 was changed to the base paper 10. The ash content of the base paper 10 was 17.2%.

Example 13 An ink jet recording paper of Example 13 was produced in the same manner as in Example 11, except that the base paper 11 used in the Example 11 was changed to the base paper 8. The ash content of the base paper 8 was 19.7%.

Example 14 An ink jet recording sheet of Example 14 was produced in the same manner as in Example 11, except that the base paper 11 used in Example 11 was changed to the base paper 12. The ash content of the base paper 12 was 4.8%.

Example 15 An ink jet recording sheet of Example 15 was produced in the same manner as in Example 11, except that the base paper 11 used in Example 11 was changed to the base paper 9. The ash content of the base paper 9 was 22.3%.

With respect to the recording papers of Examples 10 to 15 produced as described above, the ISO whiteness, the fluorescence intensity, and the ink jet suitability of the papers were measured by the evaluation methods described above. The surface strength was measured according to the following measurement method. Table 2 shows the results.

1) Surface Strength The sample to be measured was conditioned for 24 hours in an environment of 20 ° C. and 65% RH, and then a commercially available 18 mm wide Sehan adhesive tape (Nichiban, Cellotape) was attached at a linear pressure of 300 g / cm. ,
1 cm / sec. When the tape was peeled at a speed of, the amount of powder adhering to the tape was determined. As evaluation criteria,
A: The powder hardly adheres to the tape, and the surface strength is strong. B:
The powder slightly adheres to the tape, but there is no problem in practical use.
C: Powder adhered to the tape, causing a problem depending on the use conditions. D: Powder considerably adhered to the tape, which was a practical problem. .

[0090]

[Table 2]

Considering the results of the above evaluation,
As can be clearly seen from １３13, a base paper having an ash content of calcium carbonate of 5 to 20% as a filler is provided with a fluorescent whitening agent, a dye and a pigment,
A coating solution containing a water-soluble binder and a cationic polymer fixing agent as main components is applied, and JIS P-81 is applied using a xenon flash lamp of the coated paper as a light source.
The combination of the ISO whiteness of 95% or more and the fluorescence intensity of 7 to 15% measured by the measurement method specified in No. 48 provides high image density, water resistance and image reproducibility. It can be seen that ink jet paper excellent in surface strength can be obtained. When the ash content of calcium carbonate exceeds 20% as in Example 19, the water resistance, the image density and the image reproducibility are improved, but it is also apparent that the surface strength is greatly deteriorated. Further, when the ash content of calcium carbonate is lower than 5% as in Example 18, although the surface strength is maintained, the water resistance, image density and image reproducibility are reduced.

For the purpose of clarifying the features of the third invention by the combination of Examples 16 to 25 and Comparative Examples 9 to 10, base papers 13 to 14 were prepared according to the following composition.

<Base paper formulation 13> Base paper formulation; LBKP (freeness: 450 ml, csf) 100 parts Calcium carbonate (TP-121 manufactured by Okutama Industry Co., Ltd.) 12 parts Neutral rosin sizing agent (PMC Japan) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keiko BUL) 0.02 parts Amphoteric starch (Nippon NSC; Cato3210) 1.0 parts Sole Violet 57L; BASF Co., Ltd. 0.00096 Yield improver (Alight Coroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co .; Organozob O) 0.1 part

<Base Paper Mixture 14> Base paper mix; LBKP (freeness: 450 ml, csf) 80 parts Base paper mix; DIP (freeness: 400 ml, csf) 20 parts Calcium carbonate (Okutama) Industrial Co., Ltd .; TP-121) 12 parts Neutral rosin sizing agent (Nippon PMC; CC-167) 0.4 parts Aluminum sulfate 1.4 parts Fluorescent whitening agent (Nippon Soda Co., Ltd .; Keikol BUL) 0. 02 parts Amphoteric starch (manufactured by NSC Japan Ltd .; Cato3210) 1.0 part Dye (Passasol Violet 57L; manufactured by BASF) 0.00096 parts Yield improver (Allite Koroit Co .; Percoll 57) 0.025 parts Yield improver (Alite Coroit Co., Ltd .; Organosorb O) 0.1 parts

A 0.3% slurry having the above composition was mixed with a milling width of 1,3.
00 mm, papermaking speed 150 m / min. A base paper having a basis weight of 78.4 g / m ² and a water content of 5.0% was produced by a Fourdrinier paper machine, and this was used as a base paper for size press.

Next, ink jet recording papers of Examples and Comparative Examples were prepared according to the following method.

Example 16 The base paper 13 prepared as described above was subjected to size press with one composition of a size press liquid to obtain an ink jet recording sheet having a solid content of 3.0 g / m ^2. did. The ash content of the base paper 13 at this time was 10.7%
Met.

Example 17 A mixture of the size press liquid 1 of Example 16 and the size press liquid 2
An ink jet recording paper of Example 17 was produced in the same manner except that the composition was used.

Example 18 A mixture of the size press solution 1 of Example 16 and the size press solution 3
An ink jet recording paper of Example 18 was produced in the same manner except that the composition was used.

Example 19 A mixture of the size press solution 1 of Example 16 and the size press solution 4
An ink jet recording paper of Example 19 was produced in the same manner except that the composition was used.

Example 20 A size press was performed on the base paper 14 prepared above with one size press solution to obtain an ink jet recording sheet having a solid content of 3.0 g / m ^2. did. The ash content of the base paper 14 at this time was 10.9%
Met.

Example 21 The size press solution 1 of Example 16 was mixed with the size press solution 1
An ink-jet recording sheet of Example 21 was prepared in the same manner except that 0 was used. <10 presses of size press liquid> 5 parts of oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 0.71 parts of cationic polymer fixing agent (manufactured by Himo Co., Ltd .; SC-600G2) (BRAL) 0.5 part Cationic surface size agent (manufactured by BASF; Haspford last 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo; TB1548) (Violet) 0.003 parts Water 93.683 parts

Example 22 Ink jet recording of Example 22 was carried out in the same manner as in Example 16 except that the size press solution was changed to the acrylamide-diallylamine copolymer to change the cationic polymer fixing agent to the acrylamide-diallylamine copolymer. Paper was made. <Composition of size press liquid 11> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (commercially available acrylamide-diallylamine copolymer) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.5 parts Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB536 blue) 0.004 parts Color pigment (manufactured by Dainichi Seika Kogyo Co., Ltd .; TB1548 violet) 0.003 parts Water 93.393 parts

Example 23 The ink-jet method of Example 23 was repeated in the same manner as in Example 16 except that the size press solution was changed to the dimethylamine-epichlorohydrin polycondensate, and the cationic polymer fixing agent was changed to dimethylamine-epichlorohydrin polycondensate. Recording paper was prepared. <Combined size press solution 12> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (commercially available dimethylamine-epichlorohydrin polycondensate) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.5 part Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Colored pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Colored pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) ) 0.003 parts Water 93.393 parts

Example 24 An ink jet recording sheet of Example 24 was prepared in the same manner as in Example 16 except that the size press solution was changed to a triazole derivative, and the size press solution was changed to a triazole derivative. <Composition of size press solution 13> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Co., SC-600G2) 3 parts Fluorescent whitening agent (commercially available triazole derivative) 1.5 parts 0.1 parts of cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.14 coloring pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 parts coloring pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 part 92.493 parts of water

Example 25 An ink jet recording sheet of Example 25 was prepared in the same manner as in Example 16 except that the size press solution was changed to the imidazole derivative and the size press solution was changed to the imidazole derivative. <Composition of size press liquid 14> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Co .; SC-600G2) 3 parts Fluorescent brightener (commercially available imidazole derivative) 1.0 part 0.1 parts of cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.14 coloring pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 parts coloring pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 part 92.893 parts of water

Comparative Example 9 The composition of the size press liquid 1 of Example 16 was combined with the size press liquid 1
An ink jet recording paper of Comparative Example 9 was prepared in the same manner except that the composition was changed to five. <Composition of size press liquid 15> Oxidized starch (manufactured by Nippon Shokuhin Kako Co., Ltd .; MS3800) 3 parts Cationic polymer fixing agent (manufactured by Himo Corporation; SC-600G2) 3 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.4 part Cationic surface size agent (manufactured by BASF; ABSOFLAST 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 part Color pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 parts Water 93.493 parts

Comparative Example 10 The size press liquid 1 of Example 16 was mixed with the size press liquid 1
An ink jet recording paper of Comparative Example 10 was produced in the same manner except that the composition was changed to six. <Composition of size press liquid 16> Cationic polymer fixing agent (manufactured by Hymo; SC-600G2) 6 parts Fluorescent whitening agent (manufactured by Nippon Soda Co., Ltd .; Keikol BRAL) 0.9 part Cationic surface size agent (manufactured by BASF; (Plastolast 265D) 0.1 part Color pigment (manufactured by Dainichi Seika Kogyo; TB536 blue) 0.004 parts Color pigment (manufactured by Dainichi Seika Kogyo; TB1548 violet) 0.003 parts Water 92.993 parts

With respect to the recording papers of Examples 16 to 25 and Comparative Examples 9 to 10 produced as described above, the ISO whiteness and the fluorescence intensity of the papers were measured in accordance with the evaluation methods described above. Table 3 shows the results.

The image reproducibility and surface strength suitable for inkjet were measured in accordance with the evaluation method described above. The image water resistance and print density were measured according to the following measurement methods. Table 4 shows the results.

1) Water Resistance of Images Characters and ruled lines were printed with an ink jet printer BJ-420J manufactured by Canon Inc., and one drop of distilled water was dropped on the printed black and magenta portions with a No. 15 syringe needle and left to dry. The degree of bleeding was visually evaluated. As evaluation criteria, A: good characteristics, B: good in practically acceptable range, C: practical problem, D: poor characteristics.

2) Print density Canon inkjet printer BJ-420J
Was used to print a full-color four-color solid pattern. After drying by standing, the optical densities of black and magenta were measured with a Macbeth densitometer. The evaluation criteria are as follows:
Two or more concentrations are preferred.

[0113]

[Table 3]

[0114]

[Table 4]

Considering the results of the above evaluation,
As is apparent from the above, the fluorescent whitening agent of the coating liquid is a diaminostilbene-disulfonic acid derivative (A), and the cationic polymer fixing agent is a polyvinyl alcohol-cation monomer graft polymer (B). When the mixing ratio A: B of the solid coating amount is in the range of 1: 6 to 2: 3, the ISO whiteness and the fluorescence intensity are high, and the image density and the water resistance are excellent in inkjet suitability. But,
As seen from Comparative Example 9, when the concentration of the fluorescent whitening agent is low and deviates from the above range, not only the ISO whiteness but also the fluorescence intensity is greatly reduced. As can be seen from Comparative Example 10, even when the concentrations are high, the same phenomenon occurs because the fluorescent brightener is deactivated by the cationic group of the fixing agent. In Example 21, on the contrary, the concentration of the cationic polymer fixing agent was low and was out of the above range, but at this time, the water resistance started to deteriorate. Further, in Examples 22 and 23, the type of the fluorescent whitening agent was changed, but in this case, the balance between the image density and the water resistance was slightly lost. In Examples 24 and 25, the kind of the cationic polymer fixing agent was changed, but the ISO whiteness and the fluorescence intensity tended to decrease, and the image density also began to deteriorate. These results
The fluorescent whitening agent is a diaminostilbene-disulfonate derivative, the cationic polymer fixing agent is a combination of a polyvinyl alcohol-cationic monomer graft polymer, and the mixing ratio A: B of the solid coating amount is adjusted. 1: 6 ~
When the ratio is within the range of 2: 3, it is clearly shown that the most preferable ink jet paper for ISO whiteness, fluorescence intensity and ink jet suitability can be obtained.

[0116]

The ink jet recording paper of the present invention is obtained by applying a coating liquid mainly composed of a dye / pigment, a water-soluble binder and a cationic polymer fixing agent to a neutral base paper mainly made of wood pulp. An ISO whiteness of 95% or more and a fluorescence intensity of 7 measured by a measurement method specified in JIS P-8148 by using a xenon flash lamp of coated paper as a light source as an ink jet recording paper. -15%, the ISO whiteness of the paper can be increased, and the image density of the recorded image can be improved while using a plain paper type inkjet recording paper.
An ink jet recording sheet having excellent color reproducibility and water resistance of a printing portion can be provided.

In the second invention, the base paper ash content according to JIS P-8126 was 20 except that calcium carbonate was used as a filler and the incineration was performed at 500 ° C. for 4 hours.
%, It is possible to provide an ink jet recording paper having a high surface strength while maintaining the above ink jet characteristics.

In the third invention, the fluorescent brightening agent (A) in the coating solution is used as a diaminostilbene-disulfonic acid derivative, and the cationic polymer fixing agent (B) is used as a polyvinyl alcohol-cation monomer graft polymer. And the mixing ratio A: B of the solid coating amount is 1: 6 to 2: 3.
To provide an ink jet recording paper having high ISO whiteness, high surface strength, excellent image density and color reproducibility of a recorded image, and water resistance of a printing portion. Can be.

Claims (5)

[Claims] 1. A neutral base paper mainly made of wood pulp,
Inkjet recording paper coated with a coating liquid containing a fluorescent whitening agent, dye / pigment, water-soluble binder and cationic polymer fixing agent as main components, and using a xenon flash lamp of the coated paper as a light source. Using JIS P-81
An ink jet recording sheet characterized by having an ISO whiteness of 95% or more and a fluorescence intensity of 7 to 15% as measured by the measurement method defined in Item 48. 2. The ink jet recording paper according to claim 1, wherein the neutral base paper is made using calcium carbonate as a filler, and the ashing is performed at 500 ° C. for 4 hours, according to JIS P-8126. Base paper ash content is 5-2
Ink jet recording paper characterized by being 0%. 3. The ink jet recording paper according to claim 1, wherein the fluorescent whitening agent of the coating liquid is a diaminostilbene-disulfonic acid derivative (A), and the cationic polymer fixing agent is polyvinyl alcohol. An ink jet recording paper, which is a cationic monomer graft polymer (B), wherein the mixing ratio A: B of the solid coating amount is in the range of 1: 6 to 2: 3. 4. The ink jet recording paper according to claim 1, wherein the coating liquid is applied using an on-machine size press of a paper machine. 5. The ink jet recording paper according to claim 1, wherein the wood pulp contains waste paper pulp.