JP2010082839A - Ink jet recording paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording paper of regular type which has high ink drying property and enables double surface printing in case of recording using a high speed, roll paper feeding type, ink jet printer, and also which has water resisting property and a high degree of whiteness. <P>SOLUTION: The ink jet recording paper used for a roll paper feeding type printer with a printing speed of 50 m/min or higher comprises applying a coating liquid containing a cationic resin, an anionic fluorescent dye, and a binding agent, but no dye, on a base paper containing pulp, rosetta type precipitated calcium carbonate as a filler and a neutral rosin sizing agent as an intercalating sizing agent, wherein the Stockight sizing degree specified by JIS-P 8122:2004 is two seconds or more and less than ten seconds and the ash content specified by JIS-P 8251:2003 is 13 to 25%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plain paper type ink jet recording paper having no ink-receiving layer containing a pigment.

  The ink jet recording method is a recording method in which fine droplets of ink ejected by various methods are attached to a recording paper such as paper to form an image or characters. This recording method is widely used for home use because it is easy to increase the speed and full color, and has low noise during recording and a low cost apparatus. On the other hand, in the field of commercial use, conventionally, variable information (such as utility bills, credit bills, receipts, delivery slips, advertisements, etc.) has been printed using an electrophotographic non-impact printer (NIP). However, in recent years, it has been replaced with printing by a high-speed ink jet printer having a line head, which is excellent in printing speed.

  By the way, the ink jet recording paper is roughly classified into a coated paper type provided with an ink receiving layer containing a pigment and a plain paper type not provided with an ink receiving layer containing a pigment. The coated paper type that can reproduce high-definition images is mainly used for digital camera image output, while the cheap plain paper type is mainly used for printing business reports, utility bills, and transfer paper. It is done.

  With the expansion of the application of ink jet recording as described above, there is a demand for a plain paper type ink jet recording paper that is inexpensive and has high whiteness. By printing on a recording sheet with high whiteness, color printing and character reproducibility are improved. In addition, plain paper type ink jet recording paper has water resistance and high ink dryness that can withstand high-speed printing, and is suitable for double-sided printing (there is little show-through and the printing information cannot be seen through from the opposite side of the printing surface. ) Etc. are required.

  Regarding the ink drying property, the high-speed ink jet printer is equipped with auxiliary drying devices such as microwave drying, high-frequency drying, cylinder drying, hot air drying, etc., but it is only auxiliary drying and does not have sufficient drying capacity. . 50 m / min. Since printing is performed at the above-described high speed, it is required that the recording paper is quickly permeated and dried after printing. This is a particularly important problem in plain paper type recording paper that does not have an ink absorbing layer.

  As a plain paper type ink jet recording paper, for example, Patent Document 1 contains pulp fiber, white inorganic mineral powder as a filler, and rosin-based size emulsion as an internal sizing agent. There has been disclosed a recording paper coated with a size press liquid containing a conductive agent.

Further, in Patent Document 2, a cationic resin is adhered in the range of 0.2 to 2.0 g / m ² , and the Bristow absorption coefficient is 1.07 to 1.90 (ml / m ² · ms ^1/2 ). A sheet for use in a high-speed inkjet printing system is described.

  Patent Document 3 discloses a polymer obtained by polymerizing a fluorescent dye and a monomer containing diallyldimethylammonium salt, a dye fixing agent, a paper coating composition containing a specific cationic polymer, and a coating thereof. A processed inkjet recording paper is described.

  Patent Document 4 contains 10% by weight of light calcium carbonate having a needle shape, a columnar shape, a spindle shape, or a whisker shape and an aspect ratio of 5 or more per paper mass as an internal sizing agent. Describes a recording paper having alkenyl succinic anhydride and having color printability.

JP 2000-071606 A JP-A-9-202042 JP 2006-241626 A JP 2005-120510 A

  However, the techniques described in Patent Documents 1 to 4 described above cannot achieve both high whiteness, ink drying property, and duplex printing suitability.

  In particular, in the case of the techniques described in Patent Documents 1 and 2, the double-sided printing suitability is often insufficient. In the case of the technique of Patent Document 3, it is necessary to mix four different cationic polymers and an anionic fluorescent dye in the coating solution, and the coating solution is poor in stability and coating suitability. . Furthermore, in the case of the technique described in Patent Document 4, a certain degree of whiteness can be obtained by using calcium carbonate as a filler. However, when recording by the ink jet recording method, the water resistance of the recording portion is insufficient. It was.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a plain paper type ink jet recording paper having high ink drying properties, capable of double-sided printing, water resistance and high whiteness.

  As a result of intensive research, the present inventors have found that at least a cationic resin and an anionic fluorescent dye are bound to a base paper containing rosetta-type light calcium carbonate as a pulp and filler and a neutral rosin sizing agent as an internal sizing agent. It has been found that the above problems can be solved by an ink jet recording paper obtained by coating a coating liquid containing an agent.

  That is, according to the present invention, the printing speed is 50 m / min. Ink jet recording paper for use in the above roll-feed type printers, which is cationic on the surface of a base paper containing rose and light calcium carbonate as a filler and a neutral rosin sizing agent as an internal sizing agent. It is formed by applying a coating solution containing a resin, an anionic fluorescent dye, and a binder and not containing a pigment, and has a Steecht sizing degree of 2 seconds to 10 seconds as defined in JIS-P 8122: 2004. And an ash content defined in JIS-P 8251: 2003 is 13% by mass to 25% by mass. In particular, the cationic resin is preferably a polyamine epihalohydrin resin, and the anionic fluorescent dye is preferably a stilbene fluorescent dye. The molecular weight of the cationic resin is preferably 10,000 or less, and the coating solution is preferably coated on a base paper using a transfer roll coater.

  According to the present invention, it is possible to obtain a plain paper type ink jet recording paper having high ink drying properties, capable of double-sided printing, water resistance, and high whiteness. The base paper contains a rosetta-type light calcium carbonate as a filler with a relatively high ash content, a neutral rosin sizing agent as an internal sizing agent, and a specified sizing degree to provide an ink receiving layer containing a pigment. These performances can be ensured even if they are not present. Furthermore, whiteness and water resistance can be further improved by applying a coating liquid containing a polyamine epihalohydrin resin and a fluorescent dye containing a stilbene-type anionic fluorescent dye and a binder. Also, by applying a coating solution containing polyamine epihalohydrin resin and fluorescent dye containing stilbene type anionic fluorescent dye and binder on both sides using a transfer roll coater, both sides are suitable for printing with high surface strength. Ink jet recording paper with excellent productivity can be manufactured stably with high productivity.

  The ink jet recording paper of the present invention is of a plain paper type obtained by coating a coating liquid containing a cationic resin and a fluorescent dye on a base paper containing the following pulp, filler, sizing agent and the like. An ink receiving layer containing a pigment is not provided.

1. Base paper <pulp>
The base paper is made from paper made of wood pulp, fillers, auxiliaries and the like. Examples of the wood pulp include known chemical pulp, mechanical pulp, and waste paper pulp. Moreover, these various pulps are used independently as needed, or are used together. As the pulp, conventionally known ones commonly used for papermaking can be used, for example, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood bleached sulfite pulp (LBSP), softwood bleached sulfite. Examples thereof include chemical pulp such as pulp (NBSP); mechanical pulp such as groundwood pulp (GP) and thermomechanical pulp (TMP); wood pulp such as waste paper pulp (DIP). Further, non-wood pulp such as cotton pulp, hemp, bagasse, kenaf, esparto, cocoon, trifoam, and husk can be used.

<Filler>
The filler internally added to the base paper mainly contains rosette type light calcium carbonate. Rosetta-type light calcium carbonate is formed by agglomerating primary particles of spindle-shaped light calcium carbonate radially to form Rosetta-type secondary particles. Specifically, Albuquer HO of Specialty Minerals Inc., Preferable products include Albuquer 5970 and Albuquer LO. Here, the radial refers to, for example, the longitudinal direction of each primary particle extending radially from the vicinity of the center of the secondary particle.

  Light calcium carbonate is excellent in terms of production cost and operability, and high whiteness and opacity can be obtained with a low addition amount. Rosetta-type light calcium carbonate has a high oil absorption because of its special shape. The ability to absorb ink is greatly improved by adding it to the base paper, and the drying property when ink jet recording is performed is greatly improved. In particular, the printing speed is 50 m / min. The effect is great when the above high-speed inkjet printer is used.

  FIG. 1 is an electron microscopic image showing an example of the form of Rosetta-type light calcium carbonate (secondary particles) in a state dispersed in a liquid. In this figure, the bases of the respective primary particles are aggregated, and each primary particle extends radially toward the tip. In addition, each primary particle has a slightly larger width (diameter) at the base and narrows toward the tip. In addition, micron in a figure shows micrometer.

  As fillers, in addition to Rosetta-type light calcium carbonate, non-Rosetta-type light calcium carbonate, heavy calcium carbonate, kaolin, talc, silica, white carbon, aluminum hydroxide, zeolite and other conventionally used inorganic fine particles are used. can do. However, the ratio of the inorganic fine particles to the entire filler is preferably about 20% by mass or less.

<Internal sizing agent>
In the present invention, a neutral rosin sizing agent is used as the internally added sizing agent. Examples of the sizing agent used in the neutral region using light calcium carbonate as a filler include alkenyl succinic anhydride (ASA) and alkyl ketene dimer (AKD) in addition to the neutral rosin sizing agent. In this case, since the friction coefficient of the paper is lowered, the problem of slipping occurs in the printing, printing process and post-processing process. On the other hand, in the case of alkenyl succinic anhydride, size development is greatly affected by other additive chemicals at the time of papermaking, so handling is difficult to ensure stable quality. For this reason, a neutral rosin sizing agent having stable expression of size and no problem of slipping is used.

  The addition rate of the neutral rosin sizing agent is preferably 0.1 to 0.5% by mass, particularly preferably 0.1 to 0.3% by mass, based on the raw material pulp. When the addition rate is less than 0.1% by mass, the drying property of the ink is good, but the feathering resistance (scratching of the printed portion) and the back-through are inferior. On the other hand, when the content exceeds 0.5% by mass, the ink drying property when printed by an ink jet printer is deteriorated, and the spread of ink droplets on the paper is suppressed, so that the original design is not formed and the white color is lost. It may produce printed matter.

  The neutral rosin sizing agent used in the present invention is an emulsion-type rosin sizing agent in which a rosin-based material is dispersed with various emulsifying dispersants, which is used in a weakly acidic to weakly antaritic region (neutral region) having a pH of 6 to 9. It is. Here, as the rosin-based material, rosin such as gum rosin, wood rosin, tall oil rosin, etc., reinforced rosin modified with α, β-unsaturated carboxylic acid such as fumaric acid, maleic acid, acrylic acid or its anhydride, Examples of the rosins include rosin esters obtained by reacting polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and diglycerin. After mixing, it is possible to use a mixture. Furthermore, what added various polymers to the said rosin emulsion in order to improve size developability can also be used.

<Making paper>
As the paper machine for making the base paper, a known apparatus such as a long net paper machine or a twin wire paper machine can be appropriately used. Among these, it is particularly preferable to carry out paper making using a twin wire paper machine because the composition difference between the front and back of the paper becomes small because dehydration is performed from the top and bottom of the raw pulp slurry. In order to obtain the ink jet recording paper in the present invention, pulp freeness, jet wire ratio, profile, press, calendar, and the like are adjusted as papermaking conditions, and the drying conditions are vapor pressure and ventilation method in a paper machine dryer. A known method such as adjustment of the above can be used. The papermaking pH can be carried out from the acidic region to the alkaline region, but is preferably a weakly acidic to weakly alkaline region (neutral region) having a pH of 6 to 9. Further, in the base paper, a paper strength enhancer, an antifoaming agent, a pH adjuster, a yield improver, a dye or colored pigment for adjusting the hue, and visual whiteness within a range not impairing the effects of the present invention. An internal additive for papermaking, such as a fluorescent dye, can be added.

2. Coating liquid <cationic resin>
In the present invention, a cationic resin that is effective as an ink fixing agent is included in the coating liquid in order to impart water resistance to the anionic ink jet ink and improve feathering resistance.

  The cationic resin is a cationic water-soluble polymer, and preferably has a molecular weight of 200,000 or less from the viewpoint of improving feathering resistance and ink water resistance. In particular, when used for the inkjet recording paper in the present invention, the molecular weight of the cationic resin is preferably 10,000 or less. The cationic density of the cationic resin is preferably 5 meq / g or more. When the cation density is less than 5 meq / g, the ink fixing ability may not be sufficient.

  The molecular weight is a mass average molecular weight measured by GPC (Gel Permeation Chromatography), and the cation density is usually (1/400) N potassium potassium sulfate (PVSK) solution as a titrant and 0.1% toluidine blue as an indicator. It is measured by a general colloid titration method using a solution, and obtained by the following calculation formula.

  Examples of cationic resins include polyethyleneimine quaternary ammonium salt derivatives; ammonia, dialkylamine, epihalohydrin resins; polyamine epihalohydrins; polyamide epihalohydrins; polyamine polyamide epihalohydrins, dicyanamide, formaldehyde resins; diethylenetriamine, dicyandiamide, ammonium chloride resins; Resins and the like are exemplified. Among these, it is particularly preferable to use a polyamine epihalohydrin resin obtained by condensation polymerization of ammonia, amines, and epihalohydrins, since the feathering resistance at the time of printing with a high-speed ink jet printer described later is further improved.

  Examples of amines used in the resin include primary amines, secondary amines, tertiary amines, polyalkylpolyamines, and alkanolamine monoamines. Specific examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, methylethylamine, methylpropylamine, methylbutylamine, methyloctylamine, methyllaurylamine, and dibenzylamine. Specific examples of the tertiary amine include trimethylamine, triethylamine, tripropylamine, triisopropylamine, tri-n-butylamine, tri-sec. -Butylamine, tri-tert. -Butylamine, tripentylamine, trihexylamine, trioctylamine, tribenzylamine and the like can be mentioned. Of these, the secondary amines dimethylamine and diethylamine are particularly preferred.

  Specifically, as the epihalohydrins in the resin, one or more selected from epichlorohydrin, epibromohydrin, epiiodohydrin, methyl epichlorohydrin, and the like can be used, and in particular, epichlorohydrin can be used. preferable.

  As a method for synthesizing the resin, for example, known methods described in JP-A-10-152544 and JP-A-10-147057 can be used. The above resins may be used alone in the ink-receiving layer coating solution, or those having different polymerization degrees may be mixed and added to the coating solution. In addition, the said resin may use what was synthesize | combined suitably and may use a commercial item.

In the present invention, the coating amount of the cationic resin is preferably 0.5 to 5.0 g / m ^{2 on} both sides, and more preferably 1.0 to 3.0 g / m ² . When the coating amount on both sides is less than 0.5 g / m ² , sufficient feathering resistance and water resistance cannot be obtained. On the other hand, even when a cationic resin with a coating amount on both sides exceeding 5.0 g / m ² is applied, the feathering resistance and water resistance are not improved any more. Therefore, it is not preferable.

<Fluorescent dye>
In the present invention, in order to obtain high whiteness, it is preferable to blend a fluorescent dye in the coating solution. Examples of the fluorescent dye include diaminostilbene type, imidazole type, oxazole type, triazole type, coumarin type, naphthalimide type, and pyrazoline type fluorescent dye. In general, anionic fluorescent dyes have poor compatibility with cationic resins, and aggregates are generated during mixing. In the present invention, the diaminostilbene type is particularly preferable as the fluorescent dye that has high compatibility with the above-described cationic resin and can provide high whiteness.

<Binder>
There is no restriction | limiting in particular in the binder contained in a coating liquid, It can select from a well-known binder appropriately. In the present invention, water-soluble polymer adhesives, synthetic emulsion adhesives and the like that can be dissolved or dispersed in water are preferable. Examples of the water-soluble polymer adhesive include starch or a modified product thereof, polyvinyl alcohol and a modified product thereof, and casein. Synthetic emulsion adhesives include acrylic resin emulsions, vinyl acetate resin emulsions, styrene butadiene latexes, urethane resin emulsions, etc., but water-soluble polymer adhesives are used in terms of printing density. It is preferable to do.
Specific examples of the binder include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, oxidized starch, hydroxylethyl etherified starch, and phosphate ester. Examples include modified starch.

<Other ingredients>
As long as the effects of the present invention are not impaired, the sizing agent, dye, water retention agent, water resistance agent, pH adjuster, antifoaming agent, lubricant, preservative, surfactant, conductive agent, UV absorption in the coating liquid It is possible to add additives such as an agent and an antioxidant.
<Coating method>
In the present invention, the coating liquid is preferably applied at a high speed (300 m / min. Or more, 1000 m / min. Or more is also possible) by a transfer roll coater. These are coating systems that can be coated on both sides at the same time and can be easily installed on a paper machine. As a result, productivity is greatly improved, and by simultaneously coating both sides of the support, inkjet recording paper capable of double-side printing can be manufactured at low cost. Examples of the transfer roll coater include a gate roll coater, a rod metering size press, a blade metering size press, and the like. A coating liquid is applied to a support by a pre-measuring method (print coating method) (a plurality of rolls or A coater that is coated with a coating liquid measured with a bar, blade, etc. on the support using an application roll, and a post-weighing method (blade coater, bar coater, etc.) (scraps the coating liquid adhering to the support) Compared with the coater that coats the coating method, there is an advantage that it is difficult to cut the paper because the load on the paper during coating is small, and coating can be performed at a higher speed. Further, when a transfer roll coater is used, the thickness of the coating film formed on the base paper becomes uniform, and the feathering resistance is further improved.

  In the present invention, the transfer roll coater may be an on-machine coater or an off-machine coater. An on-machine coater is installed on a support production machine (such as a paper machine) and is applied on the same line as the production of the support. The off-machine coater is installed separately from the support production machine. The manufactured support is wound up once and coated with a coater on another line. In terms of improving production efficiency and reducing costs, it is preferable to use an on-machine coater transfer roll coater. In addition, blade coaters, air knife coaters, bar coaters, curtain coaters, etc. are used as coating methods in the production of conventional ink jet recording paper, but it is difficult to apply both sides to the support simultaneously using these methods. However, double-sided coating has problems such as an increase in the number of manufacturing steps and an increase in drying load.

<Ash content>
The ash content defined in JIS-P 8251: 2003 of the ink jet recording paper of the present invention is required to be 13% by mass to 25% by mass, and preferably 14% by mass to 20% by mass. When the ash content is 13% by mass to 25% by mass, the ink drying property at the time of ink jet recording is improved and the double-sided printing suitability is improved. On the other hand, if the ash content is less than 13% by mass, the double-sided printing suitability is deteriorated because it easily passes through, and if it exceeds 25% by mass, the ink cannot control the penetration of the ink in the lateral direction in the recording paper, and the ink In addition to being easy to see, it becomes easy to fall off. The ash content specified in JIS-P 8251: 2003 represents the amount of ashing residue after burning the sample (paper) at a temperature of 525 ° C. ± 25 ° C. as a percentage of the absolute dry mass of the sample. Is.
<Stick human sizing degree>
In the present invention, it is further necessary that the Steecht sizing degree defined in JIS-P 8122: 2004 as an ink jet recording sheet is 2 seconds or more and less than 10 seconds. If the Steecht sizing degree is less than 2 seconds, the ink applied to the ink jet recording paper tends to spread in the horizontal direction, and the feathering resistance is significantly reduced. Decreases. On the other hand, when the Steecht sizing degree exceeds 10 seconds, the ink drying property is lowered.

  The degree of Steecht sizing can be adjusted by the content of the internal sizing agent in the base paper, the coating amount of each component constituting the coating liquid, and the like. For example, the sizing degree increases as the content of the internal sizing agent in the base paper increases, and the sizing degree decreases as the coating amount of the cationic resin increases.

<Printing>
The high-speed inkjet printer in the present invention is a printing speed of 50 m / min. This refers to the roll feed type printer described above. The ink jet printer is equipped with a line head for each ink color, enabling high-speed printing. The ink is classified into an aqueous dye type or an aqueous pigment type. In addition, auxiliary drying devices such as microwave drying, high frequency drying, cylinder drying, and hot air drying are installed. Specific examples include VX5000e manufactured by Kodak versamark, Iseto Superjet 4000 manufactured by Iseto, and MJP600 manufactured by Miyakoshi.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example. The following “parts” and “%” refer to “parts by mass” and “mass%”, respectively, unless otherwise specified.

[Example 1]
A pulp slurry consisting of 100% hardwood kraft pulp (freeness 360 ml csf), Rosetta type light calcium carbonate (Albuquer 5970: manufactured by SMI) as a filler, 20% per dry pulp mass, sulfate band 1.2%, neutral rosin sizing agent (CC1401: produced by Seiko PMC) as an internal sizing agent, 0.2%, and cationized starch (CATO304: manufactured by NSC Japan) by 0.7% A raw slurry was obtained. Using a twin wire type paper machine, this is 800 m / min. A base paper obtained by papermaking at a rate of 80 g / m ² at a speed of 10% polyoxyepihalohydrin resin (DK6802) with oxidized starch (MS # 3600: manufactured by Nippon Shokuhin Kako Co., Ltd.) 10.0% and molecular weight of several thousand. : A rod metering size press installed on-machine with a coating solution consisting of 4.0% by Seiko PMC) and 0.3% stilbene-type fluorescent dye (Kaya Hall PASQ Liquid: Nippon Kayaku Co., Ltd.) Inkjet recording paper 1 was obtained by coating to be 7 g / m ^{2 on} both sides.

[Example 2]
Inkjet recording paper 2 was prepared in the same manner as in Example 1 except that the amount of the neutral rosin sizing agent added internally to the base paper was 0.35%.

[Example 3]
Inkjet recording paper 3 was prepared in the same manner as in Example 1 except that the amount of the neutral rosin sizing agent added internally to the base paper was 0.15%.

[Example 4]
Inkjet recording paper 4 was prepared in the same manner as in Example 1 except that the amount of rosetta-type light calcium carbonate added internally to the base paper was 37% and the amount of neutral rosin sizing agent was 0.35%. .

[Example 5]
Inkjet recording paper 5 was produced in the same manner as in Example 1, except that the amount of rosetta-type light calcium carbonate added internally to the base paper was 17%.

[Example 6]
Inkjet recording paper 6 was prepared in the same manner as in Example 1 except that the polyamine epihalohydrin resin in the coating solution was changed to 2.5%.

[Comparative Example 1]
Inkjet recording paper 7 was prepared in the same manner as in Example 1 except that the amount of the neutral rosin sizing agent added internally to the base paper was 0.05%.

[Comparative Example 2]
Inkjet recording paper 8 was prepared in the same manner as in Example 1 except that the amount of the neutral rosin sizing agent added internally to the base paper was 0.4%.

[Comparative Example 3]
Inkjet recording paper 9 was produced in the same manner as in Example 1 except that the fluorescent dye in the coating solution was not used.
[Comparative Example 4]
Inkjet recording paper 10 was produced in the same manner as in Example 1 except that the polyamine epihalohydrin resin in the coating solution was not used.

[Comparative Example 5]
Inkjet recording paper 11 was produced in the same manner as in Example 1, except that the amount of rosetta-type light calcium carbonate added internally to the base paper was 12%.

[Comparative Example 6]
Inkjet recording paper 12 was prepared in the same manner as in Example 1, except that the amount of rosetta-type light calcium carbonate added internally to the base paper was 43%.

<Evaluation Item-Physical Properties of Inkjet Recording Paper>
-Ash content Based on JIS-P 8251: 2003, the ash content of 525 degreeC of each inkjet recording paper was measured.
ISO whiteness The ISO whiteness (UV-in) of each inkjet recording paper was measured in accordance with JIS-P 8148: 2001 (ISO 2470: 99). If it exceeds 90%, the whiteness is sufficiently high and good.
-Sticky sizing degree The sticky sizing degree of each inkjet recording paper was measured according to JIS-P 8122: 2004.

<Inkjet recording with water-based ink>
About each recording paper, inkjet printing was performed using black ink (# 1040) with an inkjet printer SCITEX 6240 system printer (manufactured by SCITEX, paper passing speed 100 m / min., High-speed inkjet printer), and the following evaluation items were inkjet recorded. Suitability was evaluated. The evaluation results are shown in the table.
<Evaluation items for inkjet recording aptitude>
-Water resistance After printing the black solid print pattern 1 (50 mm width x 15 mm height), it was immersed in distilled water for 30 seconds, and the water resistance was visually determined from the degree of ink flow. If the following evaluation is (circle) and (triangle | delta), it can be used practically without a problem.
○: Ink does not flow down △: Ink has flowed down slightly ×: Ink has flowed down significantly ・ Ink dryness After printing the black solid print pattern 2 (85mm width x 5mm height), touch the solid part with your finger The time required for rubbing and drying was measured. If the following evaluation is (circle) and (triangle | delta), it is the outstanding drying property.

○: Time required for drying was less than 3 seconds. Δ: Time required for drying was 3 to 6 seconds. X: Time required for drying exceeded 6 seconds.
After printing the black solid print pattern 1 (50 mm width × 15 mm height), the state of see-through when the printed portion was observed from the opposite surface was visually determined. If the following evaluation is (circle) and (triangle | delta), it can be used practically without a problem.
○: No show-through is observed Δ: Some show-through is observed, but it does not matter ×: Level of show-through is significant and affects the readability of information printed on the opposite side Examples 1-6, Comparative Example 1 Table 1 shows the results of evaluating the ink jet recording paper obtained in -6 by the above-described evaluation method.

The recording papers 1 to 6 obtained in Examples 1 to 6 corresponding to the present invention had high whiteness and good ink jet suitability (water resistance, ink drying property, duplex print suitability).
On the other hand, Comparative Example 1 having a low Steecht sizing value has poor double-sided printability, and conversely, Comparative Example 2 having a high Steecht sizing value has decreased ink drying properties.
Further, in Comparative Example 3 in which the fluorescent dye in the coating solution was not distributed, the whiteness was greatly reduced, and in Comparative Example 4 in which the cationic resin was not distributed, the water resistance was deteriorated.

  Comparative Example 5 having too little ash in the recording paper was inferior in double-sided printing suitability, Comparative Example 6 having too much ash in powder, and also poor in double-sided printing suitability due to its low Steecht size.

It is a figure which shows an example of the electron microscope image of the secondary particle shape of a rosetta type light calcium carbonate.

Claims (4)

Printing speed 50 m / min. Ink jet recording paper for use in the above-mentioned roll paper feed type ink jet printer, which is a cationic resin on a base paper containing pulp, rosetta-type light calcium carbonate as a filler, and neutral rosin sizing agent as an internal sizing agent , An anionic fluorescent dye, and a binder, and a coating liquid that does not contain a pigment, and has a Steecht sizing degree defined in JIS-P 8122: 2004 of 2 seconds or more and less than 10 seconds And the ash content prescribed | regulated to JIS-P 8251: 2003 is the ink jet recording paper which is 13 mass%-25 mass%. The inkjet recording paper according to claim 1, wherein the cationic resin is a polyamine epihalohydrin resin, and the anionic fluorescent dye is a stilbene fluorescent dye. The inkjet recording paper according to claim 1 or 2, wherein the molecular weight of the cationic resin is 10,000 or less. The inkjet recording paper according to any one of claims 1 to 3, wherein the coating liquid is applied to the base paper with a transfer roll coater.

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