JP4320306B2 - Inkjet recording medium - Google Patents

Description

  The present invention relates to an ink jet recording medium used in a printer using an ink jet recording method, and more particularly to an ink jet recording medium that prevents a glossy surface from being damaged and has excellent transportability. .

  Inkjet recording is a method for recording images, characters, etc. by ejecting micro droplets of ink by various operating principles and attaching them to a recording medium such as paper. However, it has features such as easy recording patterns, high flexibility of recording patterns, no need for development and fixing, and is rapidly spreading as a recording apparatus for various figures and color images including Chinese characters in various applications. Furthermore, an image formed by the multi-color ink jet method can obtain a recording that is comparable to multi-color printing by an offset printing method or printing by a color photographic method. In applications where the number of copies to be produced is small, a plate making process is not required as compared with the offset printing method, so that it is widely applied to the field of full-color image recording.

  Recently, inkjet printers and the like that can output high-definition images comparable to images of silver salt photographs are commercially available at low cost. Inkjet recording media are very inexpensive compared to the silver halide photography method, but are very inexpensive, so for users who frequently change the displayed image in advertisements or product samples that require large-area images. There are economic benefits. Also, it has been impossible to create an image on a personal computer, which has become popular recently, and correct the color scheme and layout while looking at this printout. There is also an advantage that such operations can be performed easily. From such a background, there is a growing demand for glossy inkjet recording media.

  As an inkjet recording medium having high glossiness, one using a cast coating method has been proposed (see Patent Document 1 and Patent Document 2).

  As a method for imparting high gloss without using the above-described casting treatment, an undercoat layer containing an alkaline earth metal salt and an adhesive and an ink receiving layer containing inorganic ultrafine particles are provided on a paper support. Inkjet recording media have been proposed (Patent Document 3).

  However, in the case of a conventional glossy inkjet recording medium, the coefficient of friction between the recording media becomes too high, causing double feeding (a phenomenon in which two sheets are overlapped) or idle feeding during ink jet printing, Scratches may occur on the surface. In the case of picture postcards and cards, there are many cases in which multiple recording media are set in a printer for continuous printing, so scratches are especially likely to occur, and the quality of prints as well as non-printed parts is significantly impaired due to scratches. This is very problematic.

  It has been proposed to contain an organic pigment in the ink receiving layer, the overcoat layer, the backing layer, etc. (see, for example, Patent Document 4, Patent Document 5, and Patent Document 6). Targeting prevention of blocking between recording media, improvement of water resistance of ink receiving layer, improvement of surface strength of ink receiving layer (prevention of powder falling), and using these techniques, an inkjet recording medium having gloss It was not possible to prevent the transportability and the glossy surface from being damaged.

Furthermore, proposals have been made to improve the transportability of the printer and the scratch resistance of the glossy surface by containing thermoplastic organic particles in the outermost layer of the glossy surface (for example, Patent Document 7, Patent Document 8, Patent Document 9). In these technologies, however, the ink absorbability tends to deteriorate due to the heat-densification of the thermoplastic resin in the ink-receiving layer due to the heating and high pressure by the calendar process and the cast process. It was difficult to achieve both high transportability and prevention of scratches on the glossy surface.
Japanese Patent Laid-Open No. 11-48604 JP 2000-85242 A JP 2003-170652 A JP-A-7-179025 Japanese Patent Application Laid-Open No. 11-277881 JP 2001-105722 A JP 2000-158803 A Japanese Patent Laid-Open No. 2000-203151 Japanese Patent Laid-Open No. 2003-226072

  An object of the present invention is to provide an ink jet recording medium which imparts excellent glossiness, absorbability and scratching properties and has improved transportability during ink jet printing.

An ink jet recording medium provided with at least one or more ink-receiving layers on a paper support and calendered and / or cast-treated, and an average of 1 to 5 times the thickness of the uppermost layer of the ink-receiving layer An inkjet recording medium comprising a silicone composite powder having a particle size , wherein the silicone composite powder has a spherical silicone rubber powder surface coated with a silicone resin .

  By containing a silicone composite powder having an average particle diameter of 1 to 5 times the thickness of the uppermost layer of the ink receiving layer, excellent glossiness, absorbability and scratch resistance are imparted, and at the time of ink jet printing. Good transportability can be obtained.

Hereinafter, the inkjet recording medium of the present invention will be described in detail.
In the present invention, the silicone composite powder is contained in the uppermost layer of the ink receiving layer, thereby having excellent abrasion and transportability.

  The mechanism by which the effect is manifested is presumed as follows. That is, since the silicone composite powder having a lower mechanical hardness than the inorganic pigment and having elasticity is exposed on the surface, the frictional resistance between the recording media is reduced, and problems such as double feeding are suppressed. . In order for the silicone composite powder to be effectively exposed on the surface, the average particle diameter needs to be 1 to 5 times the coating thickness of the uppermost layer of the ink receiving layer. Moreover, in order to maintain an effect after a calendar process and a cast process, the silicone composite powder with elasticity is more preferable. It is more preferable that the average particle diameter is 1 to 3 times the thickness of the uppermost layer of the ink receiving layer, since the color development of the ink jet recording characteristics is further improved. When the average particle diameter exceeds 5 times, the gloss and absorbency are lowered, which is not preferable. Further, the coefficient of friction between the paper and the printer transport unit is too low, which causes transportability problems such as idle feeding, which is not preferable. The shape of the silicone composite powder is not particularly limited, but it is presumed that the closer to a spherical shape, the more preferable, and a true spherical shape is most preferable. The compounding amount of the silicone composite powder is 0.1 to 5% by mass, preferably 0.5 to 2% by mass with respect to the pigment in the uppermost layer of the ink receiving layer. The ink absorbency may be deteriorated when the amount is more than 5% by mass.

  The method for measuring the coating layer thickness of the ink receiving layer is not particularly limited. For example, it can be measured by observing a cross section cut with a microtome with an electron microscope.

  The silicone composite powder of the present invention is obtained by coating the surface of a silicone rubber powder with various substances, and is not particularly limited, but is preferably a silicone rubber powder coated with a silicone resin. Silicone has an inorganic siloxane bond (Si-O-Si) as a skeleton. By changing the skeleton structure, degree of polymerization, and organic groups in the side chain, colorless and transparent oily material, elastic rubbery material, heating The resin which hardens | cures by is obtained. The silicone rubber powder has a structure in which linear dimethylpolysiloxane is cross-linked, has excellent heat resistance and cold resistance compared to general rubber, and exhibits rubber elasticity in a wide temperature range of −50 ° C. to 250 ° C. Is. The silicone rubber powder has the disadvantages that it is inferior in dispersibility in the ink-receiving layer coating solution and inferior in ink absorbability and image reproducibility.

Further, the silicone resin is a so-called polyorganosilsesquioxane resin having a structure in which a siloxane bond is crosslinked in a three-dimensional network represented by (RSiO _3/2 ) n. Excellent dispersibility in grease. The silicone composite powder is coated with a silicone resin with a silicone resin to maintain rubber elasticity, weak cohesiveness, good dispersibility in the ink receiving layer coating solution, and ink absorbability and transportability. In addition, it has become possible to achieve both high-level prevention of scratches on glossy surfaces.

  The structure of the ink receiving layer may be a single layer structure of an ink receiving layer designed to exhibit gloss, or may be a multilayer structure for the purpose of improving ink absorbability, color developability, weather resistance, and the like. As the multilayer structure, a structure in which an ink receiving layer is provided on an undercoat layer mainly composed of an inorganic pigment and a binder is preferably used.

  As the pigment used in the ink receiving layer and the undercoat layer, one or more known inorganic pigments can be used. For example, calcium carbonate, calcium sulfate, calcium silicate, magnesium carbonate, magnesium silicate, barium sulfate alkaline earth metal salts, kaolin, talc, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, Examples thereof include white inorganic pigments such as diatomaceous earth, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, and hydrolosite. Of these, porous pigments such as synthetic amorphous silica and alumina are preferably used for the ink receiving layer from the viewpoint of gloss and absorbency. In particular, vapor phase silica and pulverized wet silica or alumina are more preferable. For the undercoat layer, porous pigments such as amorphous silica and alkaline earth metal salts are also preferably used from the viewpoint of ink absorbability, and amorphous silica and calcium carbonate are particularly preferred.

  Examples of binders used in the ink receiving layer and undercoat include starch derivatives such as oxidized starch, etherified starch, and phosphate esterified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soy protein, polyvinyl alcohol or derivatives thereof. Acrylic resins such as polyvinylpyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, conjugated diene copolymer latex of methyl methacrylate-butadiene copolymer, polymer or copolymer of acrylate ester and methacrylate ester Polymer latex, vinyl polymer latex such as ethylene vinyl acetate copolymer, or functional group-modified polymer latex, melamine resin, urea resin with functional group-containing monomers such as carboxy groups of these various polymers Aqueous adhesives such as thermosetting synthetic resins, acrylic acid esters such as polymethyl methacrylate, methacrylic acid ester polymers or copolymers, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, alkyds Examples thereof include synthetic resin adhesives such as resins. The blending amount of the binder is 2 to 70% by mass, preferably 4 to 50% by mass with respect to the entire ink receiving layer or undercoat layer. If it is less than 2% by mass, the coating strength of the ink receiving layer or undercoat layer is insufficient. If it exceeds 70% by mass, the ink absorbability may be lowered.

  Furthermore, as an additive for the ink receiving layer and the undercoat layer, a dye fixing agent, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a foam suppressing agent, a release agent, a foaming agent, a penetrating agent, a coloring agent Dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, anti-bacterial agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers, and the like can be appropriately blended.

  In particular, a cation comprising a secondary amine, a tertiary amine, or a quaternary ammonium salt that forms an insoluble salt with a sulfone group, a carboxyl group, or an amino group in a water-soluble direct dye or water-soluble acid dye that is a dye component of an aqueous ink. Incorporating a functional dye fixing agent improves the color development because the dye is captured in the ink receiving layer, and also suppresses the flow and bleeding of ink due to dripping of water and moisture absorption due to the formation of a salt that is insoluble in water. preferable.

When the ink receiving layer and the undercoat layer are provided, a coating method is not particularly limited, and a known coating method can be used. For example, supports by various devices such as air knife coater, curtain coater, slide lip coater, die coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, bill blade coater, short dwell blade coater, size press, etc. Can be coated on top. Further, the coating amount (dry coating amount) of the ink receiving layer or the undercoat layer is preferably 5 to 30 g / m ² .

  In order to make the most of the effects of the present invention, the surface of the ink receiving layer is preferably subjected to a gloss development treatment. Examples of the gloss development process include a press-contact mirror finish by a cast coating method and a smoothing process by a calendar apparatus.

  There are direct contact method, coagulation method, re-wetting method (re-wetting method), etc. for the press-contact mirror finish by the cast coating method as gloss development treatment, and the coating surface of the ink receiving layer is applied, and the coated surface is wet In this method, the coated surface is contacted with a heated mirror roll, pressed, dried and peeled off to form a replica of the mirror roll surface on the coated surface. The direct method is a method in which the coating liquid is applied and then pressed against a mirror roll heated in an undried state (wet state) and dried, and the solidification method is an acid solution after the coating liquid is applied. In this method, the coated material is solidified with an alkaline solution or the like and pressed against a heated mirror roll. The solidification method also includes a thermal solidification method in which infrared rays are irradiated on the coated material to solidify the surface. The rewet method is a method in which after the coating liquid is applied and dried, the coated material is rewet with a liquid mainly composed of water, and is pressed against a heated mirror surface and dried.

  Any of these pressure-contact mirror finishes by the cast coating method can be used for the ink jet recording medium of the present invention. In addition, the surface roughness, surface temperature, diameter, pressure during pressure contact (linear pressure), coating speed, and the like of the mirror roll can be appropriately selected in the same manner as the production conditions for commercially available cast coated paper.

  In the smoothing process using a calendar device, a calendar device such as a machine calendar, a TG calendar, a super calendar, or a soft calendar can be used. In particular, it is preferable to use a calender apparatus having a configuration in which the elastic roll is continued only at one place so that both sides of the recording medium are processed under the same conditions, and the paper surface that hits the roll surface is reversed. The surface roughness, surface temperature, diameter, pressure at the time of treatment (linear pressure), treatment speed, etc. can be appropriately selected. Furthermore, in order to optimize glossiness and ink jet recording suitability, these gloss development treatments may be used in combination.

  In order to obtain a photographic tone texture, it is preferable that the 75 degree gloss value according to JIS Z8741 on the surface of the ink receiving layer is 40% or more. More preferably, it is 70% or more. When the gloss value of the ink receiving layer surface is 40% or more, it has a high glossiness but also has a high coefficient of friction between paper and paper and poor transportability, and the ink receiving layer surface tends to be severely damaged by rubbing. However, in the present invention, by including the silicone composite powder in the ink receiving layer, both the extremely high gloss and the prevention of damage to the surface of the ink receiving layer are achieved without deteriorating the ink absorbability of the glossy surface. be able to.

As a support, chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP, and CGP, wood pulp such as waste paper pulp such as DIP, and a conventionally known pigment as main components, Binder, sizing agent, fixing agent, yield improver, cationizing agent, paper strength enhancer, etc. are mixed using one or more kinds of additives such as long net paper machine, circular net paper machine, twin wire paper machine etc. Base paper manufactured by various devices, and further base paper with size press and anchor coat layer with starch, polyvinyl alcohol, etc., art paper, coat paper, cast coat paper etc. with a coat layer on them Coated paper is also included. Such a base paper and coated paper may be provided with the coating layer of the present invention as they are, or a calendar device such as a machine calendar, a TG calendar, a soft calendar may be used for the purpose of controlling flattening. . The basis weight of the support is usually 40 to 300 g / m ² , but is not particularly limited.

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, “parts” and “%” in the following formulation indicate solid parts by mass and solids mass%.

<Production of support>
Pigment having a light calcium carbonate / heavy calcium carbonate / talc mass ratio of 10/10/10 to 100 parts of wood pulp comprising 80 parts of LBKP (freeness 400 mlcsf) and 20 parts NBKP (freeness 450 mlcsf) A pulp slurry having a solid content concentration of 1% containing 25 parts, 0.10 parts of a commercially available alkyl ketene dimer, 0.03 parts of a commercially available cationic polyacrylamide, 0.80 parts of a commercially available cationized starch, and 0.40 parts of a sulfuric acid band. After preparation, the paper was made using a long paper machine at a basis weight of 90 g / m ² to produce a “support”.

<Undercoat layer coating solution 1>
Wet method silica (Fine seal X37B: manufactured by Tokuyama Co.) and kaolin (caoblite: manufactured by Shiraishi Calcium Co.) 50/50 parts are added with appropriate amounts of ion-exchanged water and a dispersing agent, dispersed with a homomixer, and then solid as an adhesive. 30 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) dissolved in a concentration of 10% was mixed with water to prepare an undercoat layer coating solution 1 having a solid content concentration of 15%.

<Undercoat layer coating solution 2>
Add appropriate amounts of ion-exchanged water and dispersant to 50/50 parts of light calcium carbonate (Tama Pearl TP123: manufactured by Okutama Kogyo Co., Ltd.) and kaolin (Caobright: manufactured by Shiraishi Calcium Co., Ltd.), disperse with a homomixer, and heat as an adhesive. 3 parts of gelatinized urea phosphate esterified starch (MS4600: manufactured by Nippon Food Processing Co., Ltd.) and 10 parts of styrene-butadiene copolymer latex (E-1585: manufactured by Asahi Kasei Co., Ltd.) are mixed, and the undercoat layer has a solid content concentration of 45%. Coating liquid 2 was prepared.

<Ink-receiving layer coating solution A>
In 100 parts of ultrafine alumina (HP14: manufactured by Sasol Japan) having an average primary particle diameter of 14 nm, in addition to an appropriate amount of nitric acid and ion-exchanged water, the mixture is dispersed using an homomixer so that the average secondary particle diameter is 250 nm. A partial concentration 20% alumina dispersion was prepared. Furthermore, after mixing 2 parts of silicone composite powder (KMP-600: manufactured by Shin-Etsu Silicone Co., Ltd.) having an average particle size of 5 μm and 15 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) dissolved in a solid concentration of 10%, ion exchange was performed. Water was added to prepare an ink-receiving layer coating solution A having a solid content concentration of 10%.

<Ink-receiving layer coating solution B>
Add 100 parts of wet-process silica with an average primary particle diameter of 16 nm and an average secondary particle diameter of 6 μm to 4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) with a solid content concentration of 50% and an appropriate amount of ion-exchanged water. Was used to prepare a pre-dispersion. The obtained preliminary dispersion was treated with a bead mill to adjust a silica dispersion having an average secondary particle diameter of 400 nm and a solid content concentration of 25%. Furthermore, after mixing 15 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) in which 2 parts of silicone composite powder (KMP-602: manufactured by Shin-Etsu Silicone Co., Ltd.) having an average particle size of 30 μm and a solid content concentration of 10% were mixed, ion exchange was performed. Water was added to prepare an ink-receiving layer coating solution B having a solid content concentration of 10%.

<Ink-receiving layer coating solution C>
An ink receiving layer coating solution C was prepared in the same manner except that KMP-600 of the ink receiving layer coating solution A was replaced with a silicone composite powder (KMP-601: manufactured by Shin-Etsu Silicone Co., Ltd.) having an average particle size of 12 μm. .

<Ink-receiving layer coating solution D>
An appropriate amount of a dispersant and ion-exchanged water were added to 100 parts of gas phase method silica (AEROSIL300: manufactured by Nippon Aerosil Co., Ltd.) having an average primary particle diameter of 7 nm, and a preliminary dispersion was prepared using a homomixer. The obtained preliminary dispersion was treated with a bead mill to adjust a silica dispersion having an average secondary particle size of 200 nm and a solid content concentration of 20%. Furthermore, after mixing 2 parts of silicone composite powder (KMP-601: Shin-Etsu Silicone Co., Ltd.) having an average particle diameter of 12 μm and 15 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) dissolved in a solid concentration of 10%, ion exchange was performed. Water was added to prepare an ink receiving layer coating solution D having a solid content concentration of 10%.

<Ink-receiving layer coating solution E>
An ink receiving layer coating solution E was prepared in the same manner except that the KMP-600 of the ink receiving layer coating solution A was replaced with a silicone composite powder having an average particle size of 2 μm (KMP-605: manufactured by Shin-Etsu Silicone). .

<Ink-receiving layer coating solution F>
An ink receiving layer coating solution F was prepared in the same manner except that the KMP-600 of the ink receiving layer coating solution A was replaced with a polyolefin aqueous dispersion (Kemipearl W308: manufactured by Mitsui Chemicals) having an average particle size of 7 μm. .

<Ink-receiving layer coating solution G>
An ink receiving layer coating solution G was prepared in the same manner except that the KMP-600 of the ink receiving layer coating solution A was replaced with a silicone rubber powder having an average particle size of 13 μm (KMP-598: manufactured by Shin-Etsu Silicone). .

<Ink-receiving layer coating solution H>
An ink receiving layer coating solution H was prepared in the same manner except that KMP-600 of the ink receiving layer coating solution A was replaced with a silicone rubber powder having an average particle size of 5 μm (KMP-597: manufactured by Shin-Etsu Silicone). .

<Ink-Receptive Layer Coating Liquid I>
Ink-receiving layer coating solution I was prepared in the same manner except that KMP-600 of ink-receiving layer coating solution A was replaced with crosslinked acrylic particles having an average particle size of 20 μm (MR-20G: manufactured by Soken Chemical Co., Ltd.). .

<Ink-receiving layer coating solution J>
An appropriate amount of a dispersant and ion-exchanged water were added to 100 parts of gas phase method silica (AEROSIL300: manufactured by Nippon Aerosil Co., Ltd.) having an average primary particle diameter of 7 nm, and a preliminary dispersion was prepared using a homomixer. The obtained preliminary dispersion was treated with a bead mill to adjust a silica dispersion having an average secondary particle size of 200 nm and a solid content concentration of 20%. Further, 15 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) dissolved in a solid content concentration of 10% was mixed, and then ion-exchanged water was added to prepare an ink receiving layer coating solution J having a solid content concentration of 10%.

The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, on the undercoat layer, the ink receiving layer coating liquid A is applied and dried by a curtain coater so that the dry coating amount is 5 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Example 1 was processed. The coating thickness of the ink receiving layer was 5 μm.

The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, on the undercoat layer, the ink receiving layer coating solution B is applied and dried with a curtain coater so that the dry coating amount is 6 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Example 2 was processed. The coating thickness of the ink receiving layer was 6 μm.

The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid C is applied onto the undercoat layer with a curtain coater so that the dry coating amount is 10 g / m ^2, and a mirror drum having a coating surface of 100 ° C. is used while the coated surface is wet. Then, pressure contact mirror finishing was performed by a cast coating method to obtain a recording medium of Example 3. The coating thickness of the ink receiving layer was 10 μm.

The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, on the undercoat layer, the ink receiving layer coating liquid C is applied and dried with a curtain coater so that the dry coating amount is 10 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Example 4 was processed. The coating thickness of the ink receiving layer was 10 μm.

The undercoat layer coating solution 2 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid C was applied onto the undercoat layer with a curtain coater so that the dry coating amount was 8 g / m ^2, and a mirror drum with a coating surface of 100 ° C. was used while the coated surface was wet. Then, pressure-contact mirror finishing was performed by a cast coating method to obtain a recording medium of Example 5. The coating thickness of the ink receiving layer was 8 μm.

After coating and drying the ink receiving layer coating liquid D on the support prepared above so as to have a dry coating amount of 10 g / m ² using a curtain coater, smoothing is performed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Example 6 was obtained. The coating thickness of the ink receiving layer was 10 μm.

The undercoat layer coating solution 1 was applied and dried with a wire bar on each side of the support prepared above so that the dry coating amount was 15 g / m ² . Next, on each of the undercoat layers, the ink receiving layer coating liquid C was applied with a curtain coater so that the dry coating amount was 10 g / m ^2. The drum was used to perform press-contact mirror surface finishing by a cast coating method to obtain a recording medium of Example 7. The thickness of the ink receiving layer was 10 μm.

(Comparative Example 1)
The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid E is coated and dried on the undercoat layer with a curtain coater so that the dry coating amount is 8 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Comparative Example 1 was processed. The thickness of the ink receiving layer was 8 μm.

(Comparative Example 2)
The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid B is coated and dried on the undercoat layer with a curtain coater so that the dry coating amount is 5 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Comparative Example 2 was processed. The thickness of the ink receiving layer was 5 μm.

(Comparative Example 3)
The undercoat layer coating solution 1 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid F was applied onto the undercoat layer with a curtain coater so as to have a dry coating amount of 5 g / m ^2, and a mirror drum at 100 ° C. was used while the coated surface was wet. Then, pressure contact mirror finishing was performed by a cast coating method to obtain a recording medium of Comparative Example 3. The thickness of the ink receiving layer was 5 μm.

(Comparative Example 4)
The undercoat layer coating solution 2 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid G is applied onto the undercoat layer with a curtain coater so as to have a dry coating amount of 10 g / m ^2, and a mirror drum at 100 ° C. is used while the coated surface is wet. Then, pressure-contact mirror finishing was performed by a cast coating method to obtain a recording medium of Comparative Example 4. The thickness of the ink receiving layer was 10 μm.

(Comparative Example 5)
The undercoat layer coating solution 2 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, on the undercoat layer, the ink receiving layer coating liquid H is coated and dried with a curtain coater so that the dry coating amount is 5 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Comparative Example 5 was processed. The thickness of the ink receiving layer was 5 μm.

(Comparative Example 6)
The undercoat layer coating solution 2 was applied to the support prepared above with a wire bar so that the dry coating amount was 15 g / m ² . Next, the ink receiving layer coating liquid I is applied and dried on the undercoat layer with a curtain coater so that the dry coating amount is 10 g / m ² , and then smoothed at a linear pressure of 120 kN / m using a super calender device. The recording medium of Comparative Example 6 was processed. The thickness of the ink receiving layer was 10 μm.

(Comparative Example 7)
The undercoat layer coating solution 2 was applied and dried with a wire bar on each side of the support prepared above so that the dry coating amount was 15 g / m ² . Next, on each of the undercoat layers, the ink receiving layer coating liquid J is applied and dried with a curtain coater so that the dry coating amount is 5 g / m ² , and then the linear pressure is 120 kN / m using a super calender device. To obtain a recording medium of Comparative Example 7. The thickness of each ink receiving layer was 5 μm.

  The following evaluation was performed on each recording medium of the example and the comparative example. The results are shown in Table 1.

  “Glossiness” was a 75 ° glossiness measured on a non-printed portion of the surface in accordance with JIS Z8741 using a variable angle glossiness meter (VGS-1001DP) manufactured by Nippon Denshoku Industries Co., Ltd. In addition, the glossiness of both surfaces of Example 7 and Comparative Example 7 was almost the same, and only one surface was measured.

  “Absorptivity” was obtained by printing an image on the produced recording medium using an ink jet printer “PM-900C (setting: super fine, clean)” manufactured by Seiko Epson Corporation. The image used for the evaluation is composed of a black, cyan, magenta, yellow, blue, red, green 100% solid print portion and a pattern in which white characters are provided. The uniformity of the solid print portion, the boundary portion between the adjacent solid print portions, the sharpness of the white characters, and the like were visually observed and evaluated. "○" is good, "△" is slightly inferior to "○" due to the non-uniformity of the solid print part due to inferior ink absorption performance, or white characters are crushed, but there is no problem in practical use The level “x” indicates that there is a problem in practice. Regarding Example 7 and Comparative Example 7, the absorption levels on both sides were the same, and only one side was evaluated.

  “Abrasion” means that the recording medium produced is cut into A4 size, 20 sheets thereof are set in an ink-jet printer “PM-900C” manufactured by Seiko Epson Corporation, and after continuous printing, the abrasion on the glossy surface is visually observed. And evaluated. “◎” is particularly good with almost no scratches, “○” is good with slight scratches, “△” indicates scratches are noticeable but can be used, and “×” indicates severe scratches and practical problems. Represents. Regarding Example 7 and Comparative Example 7, the scratches on both sides were the same, and only one side was evaluated.

  “Conveyance” is to cut the recording medium produced to A4 size and use 100 ink jet printer “PM-900C (setting: super fine, clean)” manufactured by Seiko Epson under the conditions of 23 ° C. and 50% RH. Then, 100 black solid prints were printed on the ink receiving layer and evaluated. “○” did not cause any double feed or idle feed. In “Δ”, double feed or idle feed occurred once or twice. “×” indicates that double feed or idle feed occurred three times or more.

  Each of Examples 3 to 5 and 7 is excellent in suppressing scratching and transportability, and has excellent gloss and absorbency. In particular, Example 3 has both a very good gloss, suppression of scratching, and transportability. In Example 1, since the average particle diameter / uppermost layer thickness of the silicone composite powder is a lower limit of 1 time, the scratch resistance and transportability are at the practical lower limit level, but the white paper gloss and absorbency are excellent. In Example 2, since the average particle diameter / uppermost coating layer thickness of the silicone composite powder is an upper limit of 5 times, the glossiness and absorbency are at the practical lower limit level, but are excellent in suppressing scratching and transportability. In Example 6, since there is no undercoat layer, the absorbency and white paper gloss are at the practical lower limit level, but the average particle diameter of the silicone composite powder / the thickness of the uppermost layer is 1.2 times. The property is good.

  Comparative Examples 1, 2, 3, and 7 are not preferable because of poor transportability. In Comparative Examples 4 and 5, although scratches are slightly suppressed, the absorbability is inferior, which is not preferable. Comparative Example 6 is not preferable because of poor abrasion.

Claims (1)

In an ink jet recording medium in which at least one ink receiving layer is provided on a paper support and calendered and / or casted , the uppermost layer of the ink receiving layer is 1 to 5 times the thickness of the ink receiving layer. An inkjet recording medium comprising a silicone composite powder having an average particle diameter , wherein the silicone composite powder has a spherical silicone rubber powder surface coated with a silicone resin .