JP2017071089A - Coated paper for printing for industrial inkjet printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated paper for printing for an industrial inkjet printing machine which has good ink absorptivity and good resistance against ink strike-through, and has good wrinkle resistance on the industrial inkjet printing machine.SOLUTION: There is provided a coated paper for printing for an industrial inkjet printing machine which has base paper, and a coating layer containing a pigment and a binder on at least one surface of the base paper, where the base paper contains at least one selected from a cationic resin and a water-soluble polyvalent cation salt, a Stockigt size degree of the base paper is 10 seconds or more and 30 seconds or less and a ratio of in an MD direction/CD direction of an ultrasonic transmission speed is 1.2 or more and 1.6 or less, and a coating amount of the coating layer is 5 g/mor more and 12 g/mor less per one surface in a dry solid content.SELECTED DRAWING: None

Description

  The present invention relates to a coated paper for printing on an industrial inkjet printer used in an industrial inkjet printer used in the commercial printing field. Furthermore, it is related with the coated paper for printing for industrial inkjet printers suitable for book uses, such as on-demand publication.

  2. Description of the Related Art Industrial inkjet printers that use an inkjet recording method are well known as industrial or commercial printers for producing a large number of commercial prints because of rapid advances in inkjet recording technology (for example, patents) References 1 and 2, Non-Patent References 1 and 2). Industrial inkjet printing machines are sold under the names of SCREEN's TruepressJet, Miyakoshi's MJP series, Kodak's Prosper and VERSAMARK, Fuji Film's JetPress, and HP's WebPress.

  Such an industrial inkjet printing machine, although depending on printing conditions, has a color printing speed of 10 to several tens of times faster than that of general-use and SOHO inkjet printers and large-format inkjet printers, and a printing speed of 15 m. / Min., More than 60 m / min at higher speeds. For this reason, industrial inkjet printers are distinguished from general household and SOHO inkjet printers and large format inkjet printers.

  Industrial inkjet printers can adapt to on-demand printing because they can handle variable information. Printers print fixed information on conventional printing machines such as gravure, offset, letterpress, flexographic, thermal transfer or toner printers, and variable information on industrial inkjet printers. In many cases, such a form is adopted. Conventional printers often use offset printers particularly in terms of print image quality and manufacturing cost.

As a coated paper for printing with a texture close to that of A2 mat-coated paper having good suitability for inkjet printing without impairing offset printing suitability, a coating layer mainly composed of a pigment and a binder on at least one surface of the base paper In the coated coated paper for printing, the base paper contains a cationic compound, the coated layer contains heavy calcium carbonate as a pigment in an amount of 50 parts by mass or more with respect to 100 parts by mass of the total pigment in the coated layer, A coated paper for printing in which the coating amount of the coating layer is 2.0 g / m ² or more and 7.0 g / m ² or less per side is known (for example, see Patent Document 3).

JP 2011-251231 A JP 2005-088525 A International Publication No. WO2011 / 001955 Pamphlet

Tokasu Michiko, “B2 size printing ink jet printer” (“Printing magazine”, published by the Japan Society of Printing Press, August 2010 (Vol.93), pp. 21-24) Yasutoshi Miyagi “Inkjet Printing Machine with Offset Quality” (“Printing Magazine”, published by the Printing Society Press, August 2010 (Vol.93), pp. 25-29)

  The ink of an industrial inkjet printer has a lower ink colorant content and contains a larger amount of ink solvent than the ink of a conventional printer such as an offset printer, and therefore, an ink strike-through phenomenon is likely to occur. “Ink back-through” is a phenomenon in which the ink reaches the deep part of the base paper without stopping on the printing side, and the printed image is visually recognized from the back side of the printing side. In commercial printing, duplex printing is often performed, and ink breakthrough impairs image quality sufficient for a product.

  Further, in an industrial inkjet printer, when printing a print image having a region with a high color density, the image may be wrinkled during printing. The generation of wrinkles becomes prominent in industrial inkjet printers that are rotary. The generation of wrinkles impairs the commercial value of the printed material. The wrinkle-generating mechanism is considered to be an interaction between the elongation of the paper by the ink solvent and the tension applied to the printing paper along the flow direction during printing conveyance.

  It is important for commercial printed matter to suppress the occurrence of ink breakthrough and wrinkles. For example, it is possible to further improve these qualities compared to coated paper for printing as described in Patent Document 3. It has been demanded.

That is, the objective of this invention is providing the coated paper for printing for industrial inkjet printers which has the following performance.
(1) In printing using an industrial inkjet printer, the ink has sufficient ink absorptivity so as not to cause stains on the printed matter (ink absorptivity).
(2) In printing using an industrial inkjet printing machine, ink see-through is sufficiently suppressed (ink show-through resistance).
(3) In printing using an industrial inkjet printer, the generation of wrinkles is sufficiently suppressed (wrinkle resistance).

The object of the present invention is achieved by the following.
<1> A base paper and a coating layer containing a pigment and a binder on at least one surface of the base paper, wherein the base paper is at least one selected from a cationic resin and a water-soluble polyvalent cation salt. The stencil size of the base paper is 10 seconds or more and 30 seconds or less, and the ultrasonic transmission speed MD direction / CD direction ratio is 1.2 or more and 1.6 or less, and the coating amount of the coating layer is 5 g / m ² or more 12 g / m ² or less is an inkjet printer for coated printing paper for industrial single-sided per dry solid content.

  <2> The pigment of the coating layer is at least kaolin and heavy calcium carbonate, and the coating layer has a kaolin content of 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the pigment in the coating layer. The coated paper for printing for industrial inkjet printing machines as described in <1>, wherein the calcium carbonate is contained in the range of 10 parts by mass or more and 40 parts by mass or less.

  <3> The coated paper for printing for an industrial inkjet printer according to the above <1> or <2>, wherein the Steecht sizing degree is 10 seconds or more and 30 seconds or less.

<4> CD direction Clark stiffness is 15cm ^3/100 or more 35 cm ^3/100 or less, the <1> to industrial inkjet printing machines for coated printing paper according to any one of <3>.

  <5> The coated paper for printing for industrial inkjet printers according to any one of <1> to <4>, which is used for books having a length of 260 mm or less and a width of 190 mm or less.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a coated paper for printing for an industrial inkjet printing machine that has good ink absorbability, ink penetration resistance and wrinkle resistance.

  Hereafter, the coated paper for printing for industrial inkjet printers of this invention is demonstrated in detail. As used herein, “inkjet printing” refers to printing using an industrial inkjet printer.

  Ink types installed in industrial inkjet printers include aqueous dye inks whose color material is a dye and aqueous pigment inks whose color material is a pigment. In the present invention, any kind of ink may be used for the industrial inkjet printer.

  If variable information and fixed information exist in the image to be printed, a part or all of the fixed information can be transferred from conventional methods such as gravure printers, offset printers, letterpress printers, flexographic printers, thermal transfer printers or toner printers. It is preferable to print using a printing machine. In particular, an offset printing machine is preferable in terms of manufacturing cost and printing quality. A conventional printing machine may be before or after printing using an industrial inkjet printing machine.

  The gravure printing machine is a type of printing machine that transfers ink to a printing medium through a roll-shaped plate cylinder in which an image is engraved. The offset printing machine is an indirect printing type printing machine in which ink is once transferred to a blanket and then transferred again to a printing medium. The letterpress printing machine is a letterpress type printing machine that performs printing by applying pressure so that the ink applied to the letterpress is pressed against the printing medium. A flexographic printing machine is a letterpress type printing machine that uses a flexible and elastic resin plate. The thermal transfer printer is a printer that uses ink ribbons of various colors, and is a printer that transfers a color material from an ink ribbon to a printing medium by heat. The toner printing machine is an electrophotographic printing machine that transfers toner to a printing material using static electricity from toner adhering to a charging drum.

  The base paper of the present invention includes chemical pulps such as LBKP (Laubholz Bleached Kraft Pulp) and NBKP (Nadelholz Bleached Kraft Pulp), GP (Groundwood Pulp), PGW (Pressure Ground Wood pulp), RMP (Refiner Mechanical Pulp), TMP (ThermoMechanical Pulp). ), Cellulose pulp selected from mechanical pulp such as CTMP (ChemiThermoMechanical Pulp), CMP (ChemiMechanical Pulp), CGP (ChemiGroundwood Pulp), and waste paper pulp such as DIP (DeInked Pulp) (these are combined alone or in combination of two or more) Or other known additives such as sizing agent, fixing agent, retention agent, cationizing agent, and the like. Paper made with

  Paper materials include other additives such as pigment dispersants, thickeners, fluidity improvers, antifoaming agents, foam inhibitors, mold release agents, foaming agents, penetrants, colored dyes, colored pigments, fluorescent whitening An agent, an ultraviolet absorber, an antioxidant, an antiseptic, an antibacterial agent, a waterproofing agent, a wet paper strength enhancer, a dry paper strength enhancer, and the like, as long as the desired effects of the present invention are not impaired. Can do.

  The Steecht sizing degree according to the present invention is a value measured using a method defined in JIS P 8122: 2004. The base paper of the present invention has a Steecht sizing degree of 10 seconds to 30 seconds. In the case where the sizing degree of the base paper is less than 10 seconds, the ink penetration resistance is poor. When the base paper has a sizing degree of more than 30 seconds, the ink absorbability is poor.

  The degree of sizing of the base paper is a conventionally known physical property value in the papermaking field, and can be adjusted by a conventionally known method. For example, it can be adjusted by papermaking conditions, use of various sizing agents, filler type and blending amount, and the like. In the use of various sizing agents, the Steecht sizing degree can be adjusted by the type and content of the internal sizing agent and the type and coating amount of the surface sizing agent applied to the base paper. Use of various sizing agents is preferable because adjustment is easy. The internal sizing agent is, for example, rosin sizing agent for acidic paper, alkenyl succinic anhydride, alkyl ketene dimer, neutral rosin sizing agent or cationic styrene-acrylic sizing agent for neutral paper. is there. The surface sizing agent is, for example, a styrene-acrylic sizing agent, an olefin sizing agent, or a styrene-maleic acid sizing agent.

  The base paper of the present invention contains at least one selected from a cationic resin and a water-soluble polyvalent cation salt.

  The method of adding at least one selected from a cationic resin and a water-soluble polyvalent cation salt to the base paper is as follows: (1) A method of adding paper to the paper and making paper; (2) Adding to the size press liquid There are a method of applying using a size press, (3) a method of adding to the surface treatment liquid and applying using a coating means such as a curtain coater or an air knife coater other than the size press. In the present invention, the method of (2) is preferred as the method for containing at least one selected from a cationic resin and a water-soluble polyvalent cation salt in the base paper. The reason for this is that the method (2) can most uniformly contain at least one selected from a cationic resin and a water-soluble polyvalent cation salt in the vicinity of the surface of the base paper.

  In the present invention, the cationic resin is a cationic polymer or a cationic oligomer, and conventionally known ones can be used. Preferred cationic resins are polymers or oligomers containing primary to tertiary amines or quaternary ammonium salts that readily coordinate with protons and dissociate when dissolved in water to exhibit cationic properties. Specific examples of the cationic resin include polyethyleneimine, polyvinyl pyridine, polyamine sulfone, polydialkylaminoethyl methacrylate, polydialkylaminoethyl acrylate, polydialkylaminoethyl methacrylamide, polydialkylaminoethyl acrylamide, polyepoxyamine, polyamidoamine, Compounds such as dicyandiamide-formalin condensate, polyvinylamine, polyallylamine and their hydrochlorides, and further polydiallyldimethylammonium chloride and copolymers of diallyldimethylammonium chloride and acrylamide, polydiallylmethylamine hydrochloride, dimethylamine- Aliphatic monoamines such as epichlorohydrin polycondensate and diethylenetriamine-epichlorohydrin polycondensate Or there may be mentioned polycondensation products of aliphatic polyamines and epihalohydrins compounds, but are not limited to. From the viewpoint of commercial availability, dimethylamine-epichlorohydrin polycondensate is preferred. In the present invention, the average molecular weight of the cationic resin is not particularly limited, but is preferably in the range of 500 or more and 20,000 or less.

  In the present invention, the water-soluble polyvalent cation salt is a water-soluble salt containing a metal polyvalent cation. A preferred polyvalent cation salt is a salt that contains a polyvalent metal cation and can be dissolved in water at 20 ° C. in an amount of 1% by mass or more. Examples of polyvalent cations of metals include divalent cations such as magnesium, calcium, strontium, barium, nickel, zinc, copper, iron, cobalt, tin and manganese; trivalent cations such as aluminum, iron and chromium Or tetravalent cations such as titanium and zirconium; and complex ions thereof. The anion that forms a salt with the metal polyvalent cation may be either an inorganic acid or an organic acid, and is not particularly limited. Examples of inorganic acids include hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, and the like. Examples of the organic acid include formic acid, acetic acid, lactic acid, citric acid, oxalic acid, succinic acid, and organic sulfonic acid. However, the sulfuric acid band used as a sizing agent is excluded.

  In the present invention, the water-soluble polyvalent cation salt is preferably a calcium salt such as calcium chloride, calcium formate, calcium nitrate, or calcium acetate. This is because the ink absorbability for an industrial inkjet printer becomes better while having offset printability. From the viewpoint of chemical cost, calcium chloride or calcium nitrate is preferable.

  In the case of “(2) Method of adding to size press liquid and applying using size press” as a method of incorporating at least one selected from cationic resins and water-soluble polyvalent cation salts into base paper, size press In addition to at least one selected from a cationic resin and a water-soluble polyvalent cation salt, a conventionally known surface sizing agent can be added to the liquid.

  The size press is a conventionally known method. Examples of size presses include an incline size press, a horizontal size press, a rod metalling size press, a roll metalling size press, a blade metalling size press as a film transfer system, and a rod metalling size press with a shim sizer, an optimizer, A gate roll coater can be mentioned as a speed sizer, a film press, and a roll metering size press. In addition, a bill blade coater, a twin blade coater, a bellbapa coater, a tab size press, a calendar size press, and the like can be given. Preferred are an incline size press, a horizontal size press, a gate roll coater, a shim sizer, and a film press.

The content in terms of dry solid content in at least one base paper selected from a cationic resin and a water-soluble polyvalent cation salt is preferably 0.2 g / m ² or more and 8.0 g / m ² or less. In the case of “(2) Method of adding to size press liquid and applying using size press”, the dry solid content conversion content per side is preferably 0.1 g / m ² or more and 4.0 g / m ² or less. Content means the dry solid content conversion content in the base paper which totaled all the compounds chosen from cationic resin and water-soluble polyvalent cation salt. In the case of “(2) Method of adding to size press liquid and applying using size press”, it can be determined from the coating amount in terms of dry solid content by size press. When the content in terms of dry solid content in at least one base paper selected from a cationic resin and a water-soluble polyvalent cation salt is in the above range, the ink-resistant back of the coated paper for printing for industrial inkjet printing machines Detachability becomes better.

  The ultrasonic transmission speed MD direction / CD direction ratio according to the present invention is determined by using, for example, “SONIC SHEEET TESTER” manufactured by Nomura Corporation, and the ultrasonic propagation speed (Vmd) in the MD direction and the ultrasonic propagation speed (Vcd) in the CD direction. Is the ratio (Vmd / Vcd). The ultrasonic transmission speed MD direction / CD direction ratio generally indicates the orientation of the pulp fibers in the base paper. The base paper of the present invention has an ultrasonic transmission speed MD direction / CD direction ratio of 1.2 to 1.6. When the ultrasonic transmission speed MD direction / CD direction ratio is less than 1.2, the ink penetration resistance is poor. When the ultrasonic transmission speed MD direction / CD direction ratio exceeds 1.6, the wrinkle resistance is poor. The reason for this is not clear, but it is thought that by using a base paper having an appropriate orientation, it is possible to obtain ink penetration resistance and wrinkle resistance.

  The ultrasonic transmission speed MD direction / CD direction ratio is determined by the papermaking conditions in the paper machine. The paper making conditions on the paper machine include optimization of paper making speed, ratio of fiber suspension jet inflow speed to wire speed (J / W ratio), wire shaking, forming board and weir plate arrangement, dandy roll, etc. It is done. The MD direction is the paper machine flow direction, and the CD direction is a direction orthogonal to the MD direction.

The coating amount of the coating layer of the printing paper for industrial inkjet printers is 5 g / m ² or more and 12 g / m ² or less in terms of dry solid content per side. When the coating amount is less than 5 g / m ² , the ink penetration resistance of printing coated paper for industrial inkjet printing machines is inferior. When the coating amount exceeds 12 g / m ² , the ink absorbability may be inferior when kaolin is used as the pigment of the coating layer, which is not preferable.

  In the coating layer of the present invention, the pigment of the coating layer is preferably at least kaolin and heavy calcium carbonate, and the kaolin is 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the pigment in the coating layer. And heavy calcium carbonate is preferably contained in the range of 10 parts by mass or more and 40 parts by mass or less. When the pigment of the coating layer satisfies the above conditions, the effect of ink absorbability or ink penetration resistance is further improved.

  The coating layer can contain a conventionally known pigment in addition to kaolin and heavy calcium carbonate. Examples of conventionally known pigments include talc, light calcium carbonate, satin white, lithopone, titanium oxide, zinc oxide, synthetic silica, alumina and aluminum hydroxide, and various organic pigments.

  The coating layer of the present invention contains a binder. The binder is a conventionally known binder, for example, polyacrylic acid type such as sodium polyacrylate, polyacrylamide, polyvinyl acetate type, styrene-butadiene copolymer, various copolymer latexes such as ethylene-vinyl acetate, Examples include polyvinyl alcohol, modified polyvinyl alcohol, formalin resins such as polyethylene oxide, urea and melamine, and water-soluble synthetic compounds such as polyethyleneimine and polyamidepolyamine-epichlorohydrin. Furthermore, starch purified from natural plants, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch and cold water soluble starch obtained by flash drying them, dextrin, mannan, chitosan, Examples thereof include natural polysaccharides such as arabinogalactan, glycogen, inulin, pectin, hyaluronic acid, carboxymethylcellulose and hydroxyethylcellulose, oligomers thereof, and modified products thereof. Further, natural proteins such as casein, gelatin, soybean protein and collagen, or modified products thereof, and synthetic polymers and oligomers such as polylactic acid and peptides can be mentioned. These can be used alone or in combination. The binder can be used after cation modification.

  The content of the binder in the coating layer is preferably 3 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the pigment in the coating layer.

  The coating layer of the present invention may contain a pigment dispersant, a thickener, an antifoaming agent, an antifoaming agent, a foaming agent, a release agent, a penetrating agent, a wetting agent, and a thermal gel as necessary in addition to the pigment and binder Various conventionally known auxiliaries such as agents, lubricants, dyes, optical brighteners or water-resistant agents can be contained.

  The coating layer of the present invention can be obtained by coating and drying the coating composition of the coating layer on a base paper. Examples of the method for coating the coating composition on the base paper include a method using a conventionally known coating apparatus. For example, various types of blade coaters such as roll coaters, air knife coaters, bar coaters, rod blade coaters, short dwell coaters, curtain coaters, and the like. Examples of the drying method include a method using a conventionally known drying apparatus. For example, a straight tunnel dryer, an arch dryer, an air loop dryer, a hot air dryer such as a sine curve air float dryer, an infrared heating dryer, a dryer using a microwave, or the like.

  In the present invention, the printing coated paper for industrial inkjet printing machines can be used in a state where the coating composition is coated and dried, but if necessary, after coating and drying, a machine calendar, software A nip calendar, a super calendar, a multi-stage calendar, a multi-nip calendar, etc. may be applied.

  However, if an excessive calendar process is performed, the gaps in the coated paper for printing for industrial inkjet printers may be crushed, resulting in a deterioration in ink absorbability. Therefore, a moderate calendar process is preferable.

  In the present invention, the coating layer can be provided on both sides of the treated base paper. It is preferable to provide a coating layer on both sides because printing can be performed on both sides depending on the printing machine.

  The coated paper for printing for industrial inkjet printers of the present invention preferably has a Steecht sizing degree of 10 seconds to 30 seconds. By satisfying the above-mentioned range for the degree of sizing of the coated paper for printing for industrial ink jet printers, it is possible to achieve better compatibility between ink penetration resistance and ink absorbability.

  The degree of sizing of the coated paper for printing for industrial inkjet printing machines is a conventionally known physical property value in the papermaking field, and can be adjusted by a conventionally known method. For example, it can be adjusted according to the pigment type and binder type of the coating layer, their blending ratio, coating amount, and calendering conditions.

  The coated paper for printing of an industrial inkjet printer according to the present invention is suitable for book use with a length of 260 mm or less and a width of 190 mm or less, and a book use is preferred.

Industrial inkjet printing machines for coated printing paper of the present invention is preferably Clark stiffness in the CD direction is 15cm ^3/100 or more 35 cm ^3/100 or less. When the Clark stiffness in the CD direction of the coated paper for printing for an industrial inkjet printer satisfies the above range, the coated paper for printing can have good handleability. In particular, when used for books, page turnability is good.

As for the coated paper for printing for industrial inkjet printers of this invention, basic weight has preferable 85 g / m < ² > or less. When the basis weight is 85 g / m ² or less, the page turning property becomes better when used for book use.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, “parts” and “%” shown in the examples indicate dry solids equivalents or parts by mass and mass% of the substantial components, unless otherwise specified. The coating amount indicates the amount of dry solid content.

(Preparation of base paper)
<Base paper 1>
To a pulp slurry consisting of 100 parts of LBKP having a freeness of 400 mlcsf, as a filler, 30 parts of light calcium carbonate (Tamapearl TP-121, manufactured by Okutama Kogyo Co., Ltd.), 0.8 parts of amphoteric starch (Cato3210, manufactured by Ingledion Japan), sulfuric acid Add 0.8 parts of band and 1.0 part of alkyl ketene dimer type sizing agent (size pine K-903, manufactured by Arakawa Chemical Co., Ltd.), and make paper with long net paper machine (J / W ratio 1.02). , size 1.5 g / ^{m 2} and per side phosphorylated starch a press device, dimethylamine - epichlorohydrin polycondensate (jet fix 36N, manufactured by Satoda Kako Co., Ltd.) was a 1.5 g / ^{m 2} is deposited, the machine calender treatment Thus, a base paper 1 was produced. At this time, the basis weight was 58.5 g / m ² .

<Base paper 2>
A base paper 2 was prepared in the same manner as the base paper 1 except that the addition amount of the alkyl ketene dimer sizing agent was 1.4 parts. At this time, the basis weight was 57.3 g / m ² .

<Base paper 3>
A base paper 3 was produced in the same manner as the base paper 1 except that the addition amount of the alkyl ketene dimer type sizing agent was 1.8 parts. At this time, the basis weight was 59.1 g / m ² .

<Base paper 4>
A base paper 4 was produced in the same manner as the base paper 2 except that the J / W ratio was 1.00. At this time, the basis weight was 57.6 g / m ² .

<Base paper 5>
A base paper 5 was produced in the same manner as the base paper 2 except that the J / W ratio was 1.04. At this time, the basis weight was 58.7 g / m ² .

<Base paper 6>
A base paper 6 was prepared in the same manner as the base paper 1 except that the addition amount of the alkyl ketene dimer type sizing agent was 0.6 parts. At this time, the basis weight was 56.1 g / m ² .

<Base paper 7>
A base paper 7 was prepared in the same manner as the base paper 1 except that the addition amount of the alkyl ketene dimer sizing agent was 2.2 parts. At this time, the basis weight was 58.7 g / m ² .

<Base paper 8>
A base paper 8 was produced in the same manner as the base paper 2 except that the J / W ratio was 0.99. At this time, the basis weight was 59.4 g / m ² .

<Base paper 9>
A base paper 9 was produced in the same manner as the base paper 2 except that the J / W ratio was 1.06. At this time, the basis weight was 58.6 g / m ² .

<Base paper 10>
A base paper 10 was prepared in the same manner as the base paper 2 except that the dimethylamine-epichlorohydrin polycondensate was not attached using a size press. At this time, the basis weight was 59.3 g / m ² .

<Base paper 11>
A base paper 11 was prepared in the same manner as the base paper 2 except that the amount of raw material sprayed onto the paper machine wire was increased. At this time, the basis weight was 67.1 g / m ² .

<Base paper 12>
A base paper 12 was produced in the same manner as the base paper 2 except that the amount of raw material sprayed onto the paper machine wire was reduced. At this time, the basis weight was 52.1 g / m ² .

<Base paper 13>
A base paper 13 was prepared in the same manner as the base paper 3 except that the amount of raw material sprayed onto the paper machine wire was reduced. At this time, the basis weight was 51.4 g / m ² .

<Base paper 14>
A base paper 14 was prepared in the same manner as the base paper 2 except that the amount of raw material sprayed onto the paper machine wire was increased. At this time, the basis weight was 72.3 g / m ² .

<Base paper 15>
A base paper 15 was produced in the same manner as the base paper 2 except that the amount of raw material sprayed onto the paper machine wire was reduced. At this time, the basis weight was 48.7 g / m ² .

<Base paper 16>
A base paper 16 was produced in the same manner as the base paper 2 except that calcium chloride was used as the dimethylamine-epichlorohydrin polycondensate. At this time, the basis weight was 57.2 g / m ² .

<Base paper 17>
A base paper 17 was produced in the same manner as the base paper 2 except that calcium nitrate was used as the dimethylamine-epichlorohydrin polycondensate. At this time, the basis weight was 58.4 g / m ² .

<Base paper 18>
Base paper 18 was prepared in the same manner as base paper 2 except that 0.75 g / m ^{2 of} dimethylamine-epichlorohydrin polycondensate (Jetfix 36N, manufactured by Satorita Chemical Co., Ltd.) and 0.75 g / m ² of calcium nitrate were attached. Was made. At this time, the basis weight was 59.1 g / m ² .

<Base paper 19>
A base paper 19 was prepared in the same manner as the base paper 2 except that the dimethylamine-epichlorohydrin polycondensate was changed to polyethyleneimine (Epomin, manufactured by Nippon Shokubai Co., Ltd.). At this time, the basis weight was 56.8 g / m ² .

(Preparation of coating composition)
<Coating composition 1>
The coating composition was prepared according to the following contents.
Kaolin (Hydra Gloss, manufactured by Huber) 75 parts Heavy calcium carbonate (FMT-90, manufactured by Phimatech) 25 parts Styrene-butadiene copolymer latex (JSR-2605G, manufactured by JSR)
10 parts Phosphate esterified starch (MS # 4600, manufactured by Nippon Shokuhin Kako Co., Ltd.) 10 parts Blended as described above, mixed and dispersed with water to adjust the concentration to 48%.

<Coating composition 2>
Coating composition 2 was prepared in the same manner as coating composition 1 except that the blending part of kaolin was 50 parts and the blending part of heavy calcium carbonate was 50 parts.

<Coating composition 3>
A coating composition 3 was prepared in the same manner as the coating composition 1 except that the blending part of kaolin was 60 parts and the blending part of heavy calcium carbonate was 40 parts.

<Coating composition 4>
Coating composition 4 was prepared in the same manner as coating composition 1 except that the kaolin blending part was 90 parts and the heavy calcium carbonate blending part was 10 parts.

<Coating composition 5>
Coating composition 5 was prepared in the same manner as coating composition 1 except that the blending number of kaolin was 100 parts and that of heavy calcium carbonate was 0 parts.

  The coated paper for printing of the industrial inkjet printer of an Example and a comparative example was produced in the following procedures.

(Preparation of coated paper for printing)
On the base paper, the coating composition was coated on both sides with an air knife coater, dried, and then calendered to produce a coated paper for printing on an industrial inkjet printer.

  Each evaluation was performed by the following method with respect to the coated paper for industrial inkjet printing machines of each Example and each comparative example obtained by said procedure. The results are shown in Table 1.

<Ink absorbability>
Using an industrial inkjet printer MJP20C manufactured by Miyakoshi Co., Ltd., an evaluation image was printed at 150 m / min with a water-based dye ink, and the degree of contamination of the solid image portion was visually evaluated. In this invention, the coated paper for printing for industrial inkjet printers which has ink absorptivity is evaluation of 3-5.
5: Good without any contamination.
4: Dirt is generated very thinly, but generally good.
3: Slight dirt is generated, but there is no practical problem.
2: The occurrence of dirt is remarkable, and there is a problem in practical use.
1: The dirt is severe and defective.

<Ink resistance to ink penetration>
An evaluation image was printed at 100 m / min with an aqueous pigment ink using an industrial inkjet printer WebPress T-300 manufactured by HP. Printing was performed by a method of recording a black solid print pattern in 10 cm × 10 cm square. The whiteness is measured from the back side of the black solid print portion using the whiteness measurement method defined in JIS P 8148, and “whiteness of white portion without printing (optical%)” — “black solid print portion The value of “whiteness (optical%) on the back side” was calculated to evaluate ink penetration resistance of the coated paper for printing. The whiteness was measured using a Nippon Denshoku PF-10 with a sample placed on a standard plate and UV cut conditions. In this invention, the coating paper for printing for industrial inkjet printers which has ink penetration resistance is evaluation of 3-5.
5: Less than 10 optical%.
4: 10 optical% or more and less than 13 optical%.
3: 13 optical% or more and less than 16 optical%.
2: 16 optical% or more and less than 19 optical%.
1: 19% optical or more.

<Wrinkle resistance>
Using an industrial inkjet printer WebPress T-300 manufactured by HP, an evaluation image was printed with an aqueous pigment ink at 100 m / min, and wrinkles generated in a black solid printing portion were visually evaluated. In this invention, the coated paper for printing for industrial inkjet printers which has wrinkle-proof property is evaluation of 3-5.
5: Good without wrinkles.
4: Although wrinkles are very weak, they are generally good.
3: Although slight wrinkles are generated, there is no practical problem.
2: The occurrence of wrinkles is remarkable and there is a problem in practical use.
1: The generation of wrinkles is severe and defective.

  Further, the page turnability of the coated paper for industrial inkjet printing machine of Example 2 and Comparative Examples 3 and 6 was evaluated as a book application by the following method. The results are shown in Table 2.

<Page turnability>
An average value of 20 people who asked the monitor to judge the ease of turning the page of the sample that was collated so that the vertical direction of the book and the MD direction of the paper were aligned and cut to a predetermined size based on the following criteria Expressed as (rounded to the nearest decimal place). In the present invention, the page turnability is considered to be good if the evaluation is 3 to 5.
5: Very easy to beat.
4: Easy to beat.
3: Neither.
2: It is hard to beat.
1: Very difficult to speak.

  From Table 1, the coated paper for industrial ink jet printing machine of each example corresponding to the present invention has good ink absorbability, good ink penetration resistance, and on an industrial ink jet printing machine. It can be seen that the wrinkle resistance is good.

  On the other hand, it can be seen from Table 1 that all the effects according to the present invention cannot be obtained in each comparative example that does not satisfy the conditions of the present invention.

  From Table 2, it can be seen that the printing coated paper for industrial ink jet printers of the present invention has good page turnability and is suitable for book use having a length of 260 mm or less and a width of 190 mm or less.

Claims (5)

A base paper and a coating layer containing a pigment and a binder on at least one side of the base paper, and the base paper contains at least one selected from a cationic resin and a water-soluble polyvalent cation salt; Further, the sizing degree of the base paper is 10 seconds or more and 30 seconds or less and the ultrasonic transmission speed MD direction / CD direction ratio is 1.2 or more and 1.6 or less, and the coating amount of the coating layer is dried per side. 5 g / ^{m 2} or more 12 g / ^m industrial inkjet printing machines for coated printing paper ² or less in solids.   The pigment of the coating layer is at least kaolin and heavy calcium carbonate, and the coating layer is 60 parts by weight or more and 90 parts by weight or less of heavy kaolin with respect to 100 parts by weight of the pigment in the coating layer. The coated paper for printing for industrial inkjet printers of Claim 1 which contains in 10-40 mass parts.   The coated paper for printing for industrial inkjet printing machines according to claim 1 or 2, wherein the Steecht sizing degree is 10 seconds or more and 30 seconds or less. CD direction Clark stiffness is industrial inkjet printing machines for coated printing paper according to claim 1 is 15cm ^3/100 or more 35 cm ^3/100 or less.   The coated paper for printing for industrial inkjet printing machines according to any one of claims 1 to 4, which is used for books having a length of 260 mm or less and a width of 190 mm or less.