JP2011212929A - Inkjet image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method capable of improving fixing offset while well keeping blocking suppressing effect.SOLUTION: The inkjet recording method has a recording step for recording the image on a recording medium by an inkjet method, an applying step or applying an inorganic particle contained in a nonvolatile solvent and having a particle size of 1 μm or more on the recorded medium. The inorganic particle includes at least one kind of inorganic compounds selected from the group consisting of silica, calcium carbonate, alumina, zirconia, and titanium oxide.

Description

  The present invention relates to an inkjet image forming method.

Inkjet technology has been applied as an image recording method for recording color images in the fields of office printers, home printers, and the like. An image formed by inkjet may be subjected to a fixing process using a fixing roller or the like in order to improve its abrasion resistance, etc., but an offset (fixing offset) at which the image portion on the recording medium is transferred to the fixing roller May occur.
Here, in Patent Document 1, as a technique for suppressing a phenomenon (blocking) in which the stacked printed products are brought into close contact with each other and the ink adheres to the back surface of another printed material, a liquid containing fine powder particles is adhered onto the paper surface. Patent Document 2 discloses forming a resin film by applying a resin liquid containing resin particles on a recording surface.

JP-A-62-246730 JP 2004-50751 A

However, in each of the above technologies, no consideration has been given to reducing the fixing offset that occurs when fixing an inkjet image.
Therefore, the present invention can improve the fixing offset while maintaining a good blocking suppression effect when applying a specific blocking inhibitor to the printed material in order to suppress blocking in the inkjet printed material. An object is to provide an ink jet image forming method.

In view of the above problems, the present inventors have intensively studied, and as a result, the inventors have solved the above problems by including the following steps. That is, the present invention relates to the following image forming method.
<1> A recording step of recording an image on a recording medium by an inkjet method, and an applying step of applying inorganic particles having a particle size of 1 μm or more contained in a non-volatile solvent on the recorded image. Inkjet image forming method.

  <2> The inkjet image forming method according to <1>, wherein the inorganic particles include at least one inorganic compound selected from the group consisting of silica, calcium carbonate, alumina, zirconia, and titanium oxide.

  <3> The inkjet image forming method according to <1> or <2>, wherein the inorganic particles are subjected to a hydrophobic treatment on the surface of the inorganic particles.

  <4> The inkjet image forming method according to any one of <1> to <3>, wherein the nonvolatile solvent is silicone oil or liquid paraffin.

  <5> The inkjet image forming method according to any one of <1> to <4>, further including a fixing step of fixing an image recorded by an inkjet method after the applying step.

  <6> The process according to any one of <1> to <5>, wherein the application step is a step of applying a non-volatile solvent containing the inorganic particles to a roller surface and bringing the roller into contact with the recording medium. 2. An ink jet image forming method according to 1.

  According to the present invention, there is provided an ink jet image forming method capable of forming an ink jet print with improved fixing offset, good blocking suppression and high abrasion resistance.

FIG. 1 is a diagram showing a schematic diagram of an apparatus during the applying step of the present invention. FIG. 2 is a diagram showing a schematic diagram of the apparatus of the forming process of the present invention.

  In the inkjet image forming method of the present invention, a recording step of recording an image on a recording medium by an inkjet method, and inorganic particles having a particle size of 1 μm or more contained in a non-volatile solvent are applied to the recorded image. A providing step. Hereinafter, each process is explained in full detail.

1. Recording Step The recording step of the present invention is a recording step for recording an image on a recording medium by an ink jet method.

(Inkjet method)
The inkjet method is not particularly limited, and is a known method, for example, a charge control method that discharges ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses vibration pressure of a piezoelectric element, an electric method An acoustic ink jet method in which a signal is converted into an acoustic beam and ink is ejected by using the radiation pressure, and ink is ejected, and thermal ink jet (Bubble Jet (registered trademark)) that uses the pressure generated by heating the ink to form bubbles. )) Any method may be used. The ink jet method includes a method of ejecting many low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent inks. The method using is included.

An ink jet head used in the ink jet method may be an on-demand method or a continuous method. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, a thermal type) Specific examples include an ink jet type, a bubble jet (registered trademark) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.) and a discharge type (for example, a spark jet type). However, any discharge method may be used.
There are no particular restrictions on the ink nozzles used when recording by the ink jet method, and they can be appropriately selected according to the purpose.

  As an inkjet head, a short serial head is used, and a shuttle system that performs recording while scanning the head in the width direction of the recording medium, and a line head in which recording elements are arranged corresponding to the entire area of one side of the recording medium There is a line system using. In the line system, an image can be recorded on the entire surface of the recording medium by scanning the recording medium in a direction orthogonal to the arrangement direction of the recording elements, and a carriage system such as a carriage for scanning a short head is not necessary. Further, since complicated scanning control of the carriage movement and the recording medium is not required, and only the recording medium is moved, the recording speed can be increased as compared with the shuttle system. The ink jet recording method of the present invention can be applied to any of these, but generally, when applied to a line system that does not use a dummy jet, the effect of improving ejection accuracy and image scratch resistance is great.

  The droplet amount of the ink composition ejected from the inkjet head is preferably 0.5 to 15 pl (picoliter), more preferably 1 to 12 pl, and still more preferably 2 to 10 pl, from the viewpoint of obtaining a high-definition image. It is.

(recoding media)
The ink jet method of the present invention records an image on a recording medium.
The recording medium is not particularly limited, and general printing paper mainly composed of cellulose, such as so-called high-quality paper, coated paper, and art paper, used for general offset printing and the like can be used.

  As the recording medium, commercially available media can be used. For example, “OK Prince fine quality” manufactured by Oji Paper Co., Ltd., “Shiorai” manufactured by Nippon Paper Industries Co., Ltd., and Nippon Paper Industries ( Fine coated paper such as “New NPI fine quality” manufactured by Co., Ltd., “OK Everlight Coat” manufactured by Oji Paper Co., Ltd., and “Aurora S” manufactured by Nippon Paper Industries Co., Ltd., Oji Lightweight coated paper (A3) such as “OK Coat L” manufactured by Paper Industries Co., Ltd. and “Aurora L” manufactured by Nippon Paper Industries Co., Ltd. “OK Top Coat +” manufactured by Oji Paper Co., Ltd. and Nippon Paper Industries Co., Ltd. ) Coated paper (A2, B2) such as “Aurora Coat” manufactured by Oji Paper Co., Ltd. Art paper (A1) such as “OK Kanfuji +” manufactured by Oji Paper Co., Ltd. and “Tokuhishi Art” manufactured by Mitsubishi Paper Industries Co., Ltd. Is mentioned. It is also possible to use various photographic papers for ink jet recording.

  Among the recording media, so-called coated paper used for general offset printing is preferable. The coated paper is obtained by applying a coating material to the surface of high-quality paper, neutral paper, or the like that is mainly surface-treated with cellulose as a main component and is not surface-treated. In particular, it is preferable to use a coated paper having a base paper and a coat layer containing kaolin and / or calcium bicarbonate. These are more preferably art paper, coated paper, lightweight coated paper, or finely coated paper.

(Ink composition)
The ink composition used in the present invention is not limited as long as it contains a coloring material and water, and a known or commercially available one can be used.

(Color material)
As the coloring material, known dyes, pigments and the like can be used without particular limitation. Among these, from the viewpoint of ink colorability, a color material that is almost insoluble or hardly soluble in water is preferable. Specific examples include various pigments, disperse dyes, oil-soluble dyes, dyes forming J aggregates, and the like, and pigments are more preferable. In the present invention, the water-insoluble pigment itself or the pigment itself surface-treated with a dispersant can be used as the color material.

  There is no restriction | limiting in particular as a pigment in this invention, A conventionally well-known organic and inorganic pigment can be used. For example, polycyclic pigments such as azo lakes, azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, diketopyrrolopyrrole pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, basic Examples include dye lakes such as dye-type lakes and acid dye-type lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments, and inorganic pigments such as titanium oxide, iron oxide, and carbon black. Any pigment not described in the color index can be used as long as it can be dispersed in the aqueous phase. Further, it is of course possible to use a pigment whose surface is treated with a surfactant, a polymer dispersing agent or the like, or graft carbon. Among the pigments, it is particularly preferable to use an azo pigment, a phthalocyanine pigment, an anthraquinone pigment, a quinacridone pigment, or a carbon black pigment.

Specific examples of the organic pigment used in the present invention are shown below. The following coloring materials may be used alone or in combination of two or more.
Examples of organic pigments for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Examples of organic pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 222C. I. Pigment violet 19 and the like.

  Examples of organic pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment Green 7 and siloxane-crosslinked aluminum phthalocyanine described in US Pat. No. 4,311,775.

  Examples of organic pigments for black include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  When the colorant in the present invention is a pigment, it may be dispersed in an aqueous solvent by a dispersant. The dispersant may be a polymer dispersant or a low molecular surfactant type dispersant. The polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.

  Among the polymer dispersants in the present invention, a hydrophilic polymer compound can be used as the water-soluble dispersant. For example, natural hydrophilic polymer compounds include plant polymers such as gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, seaweeds such as alginic acid, carrageenan and agar. Examples include molecules, animal polymers such as gelatin, casein, albumin and collagen, and microorganism polymers such as xanthene gum and dextran.

  Examples of hydrophilic polymer compounds chemically modified from natural products include fibrin polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, sodium starch glycolate, sodium starch phosphate, etc. And seaweed polymers such as alginic acid propylene glycol ester.

  Synthetic water-soluble polymer compounds include vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl methyl ether, acrylic polymers such as polyacrylamide, polyacrylic acid or alkali metal salts thereof, and water-soluble styrene acrylic resins. Resin, water-soluble styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, polyvinyl pyrrolidone, polyvinyl alcohol, alkali metal salt of β-naphthalene sulfonic acid formalin condensate, quaternary ammonium, amino group, etc. And a polymer compound having a cationic functional group salt in the side chain.

As the water-insoluble dispersant among the polymer dispersants, a polymer having both a hydrophobic part and a hydrophilic part can be used. For example, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid- (meth) acrylic acid ester copolymer, (meth) acrylic acid ester- (meth) acrylic acid copolymer, polyethylene glycol ( Examples thereof include a meth) acrylate- (meth) acrylic acid copolymer and a styrene-maleic acid copolymer.
The acid value of the polymer dispersant is preferably 100 mgKOH / g or less from the viewpoint of good aggregation when the treatment liquid comes into contact. Furthermore, the acid value is more preferably 25 to 100 mgKOH / g, and particularly preferably 30 to 90 mgKOH / g.

  The average particle diameter of the color material is preferably 10 to 200 nm, more preferably 10 to 150 nm, and still more preferably 10 to 100 nm. When the average particle size is 200 nm or less, the color reproducibility is good, the droplet ejection characteristics when droplets are ejected by the ink jet method are good, and when it is 10 nm or more, the light resistance is good. Further, the particle size distribution of the color material is not particularly limited, and may be either a wide particle size distribution or a monodisperse particle size distribution. Two or more color materials having a monodisperse particle size distribution may be mixed and used.

  The content of the color material in the ink composition is preferably 1 to 25% by mass and more preferably 2 to 20% by mass with respect to the ink composition from the viewpoint of image density.

(Polymer particles)
The ink composition of the present invention preferably contains polymer particles as necessary. Thereby, it is possible to further improve the scratch resistance, fixability, and the like of the image.

  Examples of the polymer particles in the present invention include thermoplastic, thermosetting or modified acrylic, epoxy, polyurethane, polyether, polyamide, unsaturated polyester, phenol, silicone, or fluorine. Resins, polyvinyl resins such as vinyl chloride, vinyl acetate, polyvinyl alcohol, or polyvinyl butyral, polyester resins such as alkyd resins and phthalic resins, melamine resins, melamine formaldehyde resins, aminoalkyd co-condensation resins, urea resins, urea resins And the like, or particles of a resin having an anionic group such as a copolymer or a mixture thereof. Among these, anionic acrylic resins include, for example, an acrylic monomer having an anionic group (anionic group-containing acrylic monomer) and, if necessary, other monomers copolymerizable with the anionic group-containing acrylic monomer. Obtained by polymerization in a solvent. Examples of the anionic group-containing acrylic monomer include an acrylic monomer having one or more selected from the group consisting of a carboxyl group, a sulfonic acid group, and a phosphonic group. Among them, an acrylic monomer having a carboxyl group (for example, acrylic acid) Methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid and the like), and acrylic acid or methacrylic acid is particularly preferred. The polymer particles can be used singly or in combination of two or more.

  The molecular weight range of the polymer particles in the present invention is preferably 3000 to 200,000, more preferably 5000 to 150,000, and still more preferably 10,000 to 100,000 in terms of weight average molecular weight. The said weight average molecular weight is measured by a gel permeation chromatograph (polystyrene conversion).

  The average particle diameter of the polymer particles is preferably in the range of 10 to 400 nm in terms of volume average particle diameter, more preferably in the range of 10 to 200 nm, still more preferably in the range of 10 to 100 nm, and particularly preferably in the range of 10 to 50 nm. By setting it within this range, suitability for production, storage stability and the like are improved. The average particle diameter of the polymer particles is determined by measuring the volume average particle diameter by a dynamic light scattering method using a nanotrack particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.).

  The content of the polymer particles in the liquid composition is preferably 1 to 30% by mass and more preferably 3 to 20% by mass with respect to the ink composition from the viewpoint of image glossiness and the like. preferable.

(water)
The ink composition contains water, but the amount of water is not particularly limited. Especially, the preferable content of water is 10 to 99% by mass, more preferably 30 to 80% by mass, and still more preferably 50 to 70% by mass.
(Organic solvent)
If necessary, in addition to the water, a water-soluble organic solvent may be contained. As such a water-soluble organic solvent, alkyleneoxy alcohol is preferable from the viewpoint of dischargeability. Furthermore, it is particularly preferable to contain two or more hydrophilic organic solvents containing at least one alkyleneoxy alcohol and at least one alkyleneoxy ether.

  The alkyleneoxy alcohol is preferably propyleneoxy alcohol. Examples of the propylene oxyalcohol include Sannix GP250 and Sannix GP400 (manufactured by Sanyo Chemical Industries, Ltd.).

The alkyleneoxyalkyl ether is preferably ethyleneoxyalkyl ether having 1 to 4 carbon atoms in the alkyl moiety or propyleneoxyalkyl ether having 1 to 4 carbon atoms in the alkyl moiety. Examples of the alkylene oxyalkyl ether include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether. , Triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether, and the like.
In addition to the above hydrophilic organic solvent, other organic solvents may be contained as necessary for the purpose of preventing drying, promoting penetration, adjusting viscosity, and the like.

(Other additives)
In addition to the above components, the ink composition can contain other additives as necessary. Other additives include, for example, a polymerizable compound that is polymerized by active energy rays, a polymerization initiator, an antifading agent, an emulsion stabilizer, a penetration accelerator, an ultraviolet absorber, an antiseptic, an antifungal agent, a pH adjuster, Well-known additives, such as a surface tension modifier, an antifoamer, a viscosity modifier, a wax, a dispersion stabilizer, a rust inhibitor, a chelating agent, are mentioned. These various additives may be added directly after the ink composition is prepared, or may be added when the ink composition is prepared.

2. Application Step The application step of the present invention is a step of applying inorganic particles having a particle size of 1 μm or more contained in a non-volatile solvent on the recorded image. By allowing a non-volatile solvent containing inorganic particles having a specific particle diameter to exist on the outermost surface of the recording medium, blocking of the recording medium can be suppressed while fixing offset is improved. Also, the abrasion resistance can be improved.
It is essential that the volume average particle diameter of the inorganic particles is 1 μm or more. Thereby, blocking suppression becomes possible. In particular, it is 1 μm or more and 20 μm or less, preferably 2 μm or more and 15 μm or less, more preferably 4 μm or more and 12 μm or less. The volume average particle diameter of the present invention is a value measured by a nanotrack particle size distribution measuring apparatus UPA-EX150 (manufactured by Nikkiso Co., Ltd.). Measurement may be performed by adding 10 ml of ion-exchanged water to 100 μl of 20% by mass inorganic particle aqueous dispersion to prepare a sample solution for measurement, and adjusting the temperature to 25 ° C.
Although the content of the inorganic particles to be contained in the solvent is not limited, for example, about 1 to 50% by mass, preferably about 5 to 40% by mass, more preferably about 8 to 30% by mass with respect to the total amount of the inorganic particle-containing liquid. And it is sufficient.

Examples of the inorganic particles include oxides such as silica, alumina, zirconia, and titanium oxide, fluorides such as lithium fluoride and calcium fluoride, calcium carbonate, barium sulfate, and calcium phosphate. Silica, calcium carbonate, and alumina Zirconia and titanium oxide are preferred. These may be used alone or in combination.
The inorganic particles are preferably hydrophobic. By making it hydrophobic, the inorganic particles are stably dispersed in the non-volatile solvent, and variations in performance (blocking suppression, etc.) of the printed matter obtained by the forming method of the present invention can be suppressed.

Hydrophobicity can be imparted by a hydrophobic treatment by a known method. Such a hydrophobizing treatment can be performed using a known or commercially available hydrophobizing agent such as a titanium coupling agent, a silane coupling agent, a polymer fatty acid, or a metal salt thereof. Moreover, these treatment agents may be used alone or in combination of one or more.
Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl isostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctyl pyrophosphate) oxyacetate titanate.

  Examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-. (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltri Examples include methoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane.

Examples of the polymer fatty acid and its metal salt include undecyl acid, lauric acid, undecanoic acid, myristic acid, palmitic acid, pentadecanoic acid, stearic acid, heptadecanoic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, arachidonic acid Long-chain fatty acids such as zinc salts, salts with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.
These compounds are preferably coated at a ratio of 1 to 10% by mass with respect to the inorganic particles, and more preferably 3 to 7% by mass. The treatment agent is usually formed on the surface of the inorganic particles as a monomolecular layer or a layer close thereto.

The nonvolatile solvent in the present invention refers to a solvent that does not boil at 150 ° C. or less at 1 atmosphere. Examples of such a non-volatile solvent include silicone oils such as dimethyl silicone oil, fluorosilicone oil, and amino-modified silicone oil; fluorine oil; liquid paraffin; glycerin and the like. Among these, silicone oil or liquid paraffin is more preferable from the viewpoint of fixing offset.

  As these non-volatile organic solvents, for example, specific examples of silicone oil include “KF-96-10cs”, “KF-96-20cs, KF-96-30cs”, “KF” manufactured by Shin-Etsu Chemical Co., Ltd. -96-50cs "," KF-96-100cs "," KF-96-200cs "," KF-96-300cs "," KF-96-500cs "," KF-96-1000cs "," KF-96 " -3000cs "," KF-96-5000cs "," KF-96-10000cs "," SH200-10CS "," SH200-100CS "," SH200-1000CS "," Toray Dow Corning Co., Ltd. " Dimethyl silicone oil such as SH200-10000CS; “KF-393”, “KF-859”, “KF-” manufactured by Shin-Etsu Chemical Co., Ltd. 60 "," KF-861 "," KF-864 "," KF-865 "," KF-867 "," KF-868 "," KF-869 "," KF-6012 "," KF-880 " , “KF-8002”, “KF-8004”, “KF-8005”, “KF-877”, “KF-8008”, “KF-8010”, “KF-8012”, “X-22-3820W” , “X-22-3939A”, “X-22-161A”, “X-22-161B”, “X-22-1660B-3”, “BY16-871” of Toray Dow Corning Co., Ltd., “ BY16-853U "," FZ-3705 "," SF8417 "," BY16-849 "," FZ-3785 "," BY16-890 "," BY16-208 "," BY16-893 "," FZ-3789 " , "B Amino-modified silicone oils such as Y16-878 and BY16-891; "FL-5", "X22-821", "X-22-822", "FL-100-" manufactured by Shin-Etsu Chemical Co., Ltd. 100CS "," FL-100-450CS "," FL-100-1000CS "," FL-100-10000CS "," FS1265-300CS "," FS1265-1000CS "," FS1265- "of Toray Dow Corning Co., Ltd. Fluorosilicone oil such as “10000CS”;

The liquid paraffin used by this invention will not be limited if it is a paraffin which is a liquid at normal temperature (25 degreeC). Among these, those having a density (15 ° C.) of about 0.850 to 0.905 g / cm 3 can be preferably used.
Examples of such liquid paraffin include industrial liquid paraffin and pharmacopoeia liquid paraffin. Specifically, “liquid paraffin 150-S”, “liquid paraffin 260-S”, “liquid paraffin 350-S”, “liquid paraffin No. 100”, “liquid paraffin No. 350” of Sanko Chemical Industries, Ltd. ”,“ P-100, P-120, P-150, P-200, P-260, P-350, P-350P ”of MORESCO Corporation,“ High Call M-352 ”of Kaneda Corporation, etc. Can be mentioned.

The non-volatile solvent preferably has an SP value of 30 or less. By using a solvent in this range, the image strength can be improved and the abrasion resistance can be improved. The SP value in the present invention is a value obtained by the Fedors method.
The inorganic particle-containing liquid is preferably a dispersion in which inorganic particles are in a dispersed state. In addition to the inorganic particles, known or commercially available additives (for example, those described above in the column of organic solvent) may be included.

  The present invention is a method of applying a non-volatile solvent containing inorganic particles (hereinafter also referred to as “inorganic particle-containing liquid”), but the method of applying is not limited. For example, a spray method, a coating method, A known method such as an ink jet method or an immersion method can be applied to a recording medium or the like. As a coating method, a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater or the like can be used. The details of the inkjet method are as described above.

Transfer amount to the recording medium of the inorganic particles-containing liquid (application amount) is, for example, preferably set to 1.0 g / ^{m 2} or less, and more preferably set to 0.05 to 0.5 g / ^{m 2.} Thereby, it becomes easy to apply a desired amount on the printed matter.

  In the present invention, for example, a method of applying the inorganic particle-containing liquid onto the recording medium via a roller (preferably a heating roller) is preferable. That is, it is preferable to apply the inorganic particles to the recording medium by first applying the inorganic particle-containing liquid to the roller surface, and then bringing the roller having the inorganic particle-containing liquid applied to the surface into contact with the recording medium. Thereby, it becomes easy to give a desired amount suitably.

The application method to a roller should just attach an inorganic particle content liquid directly or indirectly. Examples thereof include a method in which a cloth material impregnated with an inorganic particle-containing liquid is brought into contact with the roller surface, a method in which the inorganic particle-containing liquid is sprayed on the roller surface, and a method in which the cloth material is applied with a roll coater. In particular, the method of bringing the cloth material into contact with the roller is preferable in that an appropriate amount of the inorganic particle-containing liquid can adhere to the roller surface without unevenness.
The fabric material (web member) at this time may be either a woven fabric or a non-woven fabric, and may be a commercially available or known one, but a heat-resistant non-woven fabric is preferred from the viewpoint of contacting with a heating roller. Examples thereof include polyvinylidene chloride, polyethylene, aramid, polyester, polyamide, and a mixture thereof. The impregnation amount of the inorganic particle-containing liquid into the cloth material is not limited, but may be, for example, about 1 to 100 g / m ² (particularly ^{2 to} 50 g / m ² ). The powder particle-containing liquid is applied to the roller. In this case, if the roller is a heatable roller, it is preferable in that it can also serve as a fixing step at the same time when powder particles are applied to the recording medium via the heating roller.
An example of this preferred embodiment is shown in FIG. In FIG. 1, a cloth material 5 containing an inorganic particle-containing liquid is pressed against a heating roller (fixing roller) 1 by a web pressing roller 3. The cloth material 5 continuously feeds the inorganic particle-containing liquid to the surface of the heating roller by contacting the heating roller 1 while being wound by the rotation of the feed roller 2 and the winding roller 4.

3. Fixing Step The ink jet recording method of the present invention preferably has a fixing step for fixing the recording medium having inorganic particles applied to the image surface after the applying step. By performing this fixing process, the image on the recording medium is fixed, and the abrasion resistance against image abrasion can be further improved.

For example, the fixing step may be performed by heating and pressing the surface of the recording medium. In this case, the heating temperature is preferably in the range of 40 to 150 ° C, more preferably in the range of 50 ° C to 100 ° C, and still more preferably in the range of 60 ° C to 90 ° C.

  The pressure at the time of pressurizing with heating is preferably in the range of 0.1 to 3.0 MPa, more preferably in the range of 0.1 to 1.0 MPa, and still more preferably 0.1 in terms of surface smoothing. It is the range of -0.5MPa.

  The method of heating is not particularly limited, but a non-contact drying method such as a method of heating with a heating element such as a nichrome wire heater, a method of supplying warm air or hot air, a method of heating with a halogen lamp, an infrared lamp, etc. Preferably, it can be mentioned. The heating and pressing method is not particularly limited. For example, a method of pressing a hot plate against an image forming surface of a recording medium; a pair of heating rollers, a pair of heating and pressing belts, or an image recording surface of a recording medium There is a method of using a heating and pressing device having a heating and pressing belt arranged on the side and a holding roller arranged on the opposite side, passing a pair of rollers, etc .; Preferably mentioned.

  When pressurizing, a preferable nip time is 1 to 10 seconds, more preferably 2 to 1 second, and further preferably 4 to 100 milliseconds. Moreover, a preferable nip width is 0.1 mm to 100 mm, more preferably 0.5 mm to 50 mm, and still more preferably 1 mm to 10 mm.

  When a heating roller is used, the heating roller may be a metal metal roller, a coating layer made of an elastic body around a metal core, and a surface layer (also referred to as a release layer) as necessary. ) May be provided. The latter metal core can be formed of, for example, a cylindrical body made of iron, aluminum, SUS, or the like, and the surface of the metal core is preferably at least partially covered with a coating layer. The coating layer is particularly preferably formed of a silicone resin or fluororesin having releasability. In addition, it is preferable that a heating element is built in one core of the heating roller, and heat treatment and pressure treatment are performed simultaneously by passing a recording medium between the rollers, or as necessary. Then, the recording medium may be sandwiched and heated using two heating rollers. As the heating element, for example, a halogen lamp heater, a ceramic heater, a nichrome wire or the like is preferable.

  In the case of using a heat and pressure belt, the belt base material is preferably seamless nickel brass, and the thickness of the base material is preferably 10 to 100 μm. Further, as the material of the belt base material, aluminum, iron, polyethylene or the like can be used in addition to nickel. When silicone resin or fluororesin is provided, the thickness of the layer formed using these resins is preferably 1 to 50 μm, more preferably 10 to 30 μm.

  In order to realize the pressure (nip pressure), for example, an elastic member such as a spring having tension is selected at both ends of a roller such as a heating roller so that a desired nip pressure can be obtained in consideration of the nip gap. Install it.

The conveyance speed of the recording medium is, for example, preferably in the range of 200 to 700 mm / second, more preferably 300 to 650 mm / second, and still more preferably 400 to 600 mm / second.
In the image forming method of the present invention, a drying process may be performed by providing an apparatus such as an ink drying zone between the recording process and the applying process, between the applying process and the fixing process, and after each fixing process. Good.

  A preferred example of the forming process of the present invention will be described with reference to the schematic view of the apparatus shown in FIG. When the recording medium 11 is fed into the system by the conveying belt 10 or the like, first, the treatment liquid is applied by the treatment liquid application bar 13 in the treatment liquid application unit 12, and then the dryer 15 in the heating drying unit 14. As a result, the recording medium is dried. Thereafter, when the ink jet recording unit 16 is reached, the ink composition is ejected from the ink jet nozzle 17 toward the recording medium, and a recorded image is formed on the recording medium. The recording medium (printed material) on which the image is recorded is further conveyed to the fixing unit via the heat drying unit 14. The fixing unit includes a heating roller (fixing roller) 1 and a pressure roller 6. In the heating roller, the cloth material 5 partially impregnated with the inorganic particle-containing liquid is pressed, and as a result, inorganic particles adhere to the roller surface. The conveyed printed matter passes between the heating roller 1 and the pressure roller 6. By this passage, the image formed on the recording medium is fixed, and the inorganic particles adhering to the surface of the heating roller are transferred to the surface of the printed material. Thereafter, the sheet is cut into a predetermined size as necessary, and then discharged from the discharge port, and the printed matter is stacked on a discharge tray (not shown). In FIG. 2, first, a treatment liquid application unit 12 is provided, and a treatment liquid application step (described later) is performed on the surface of the recording medium by contacting the treatment liquid application bar. Although the heating drying part 14 is provided after 16 and the drying process is performed, these process liquid provision processes and a heating process are not essential.

(Processing liquid application process)
In addition, the image forming method of the present invention may include a treatment liquid application step for applying the treatment liquid to the recording medium. In the treatment liquid application step, a treatment liquid capable of forming an aggregate by contact with the ink composition is applied to the recording medium, and the treatment liquid is contacted with the ink composition to form an image. In this case, dispersed particles such as polymer particles and color materials (for example, pigments) in the ink composition aggregate to fix the image on the recording medium.

  The treatment liquid can be applied by applying a known method such as a coating method, an ink jet method, or an immersion method. As a coating method, a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater or the like can be used. The details of the inkjet method are as described above.

  The treatment liquid application step may be provided either before or after the ink application step using the ink composition.

  In the present invention, an embodiment in which the ink application step is provided after the treatment liquid is applied in the treatment liquid application step is preferable. That is, before applying the ink composition to the recording medium, a treatment liquid for aggregating the coloring material (preferably pigment) in the ink composition is applied in advance, and the treatment applied on the recording medium. An embodiment in which an ink composition is applied so as to come into contact with the liquid to form an image is preferable. Thereby, inkjet recording can be speeded up, and an image with high density and resolution can be obtained even at high speed recording.

The application amount of the treatment liquid is not particularly limited as long as the ink composition can be aggregated, but preferably, the application amount of the aggregation component (for example, a divalent or higher carboxylic acid or a cationic organic compound) is 0.1 g. / M ² or more. Especially, the quantity from which the provision amount of an aggregation component will be 0.1-1.0 g / m < ² > is preferable, More preferably, it is 0.2-0.8 g / m < ² >. When the amount of the aggregating component is 0.1 g / m ² or more, the agglomeration reaction proceeds favorably, and when it is 1.0 g / m ² or less, it is preferable in terms of gloss.

  The treatment liquid in the present invention is configured to be able to form an aggregate by contact with the ink composition described above. Specifically, the treatment liquid preferably includes at least an aggregating component capable of aggregating dispersed particles such as coloring material particles (pigments, etc.) in the ink composition to form an agglomerate. It can comprise using the component of. By using the treatment liquid together with the ink composition, it is possible to increase the speed of ink jet recording, and an image with excellent density and resolution can be obtained even when recording at high speed (for example, reproducibility of fine lines and fine portions).

  The treatment liquid can contain at least one aggregation component capable of forming an aggregate upon contact with the ink composition. By mixing the treatment liquid with the ink composition ejected by the ink jet method, aggregation of pigments and the like stably dispersed in the ink composition is promoted.

  Examples of the treatment liquid include a liquid capable of generating an aggregate by changing the pH of the ink composition. At this time, the pH (25 ° C.) of the treatment liquid is preferably 1 to 6, more preferably 1.2 to 5, and preferably 1.5 to 4 from the viewpoint of the aggregation rate of the ink composition. More preferably it is. In this case, the pH (25 ° C.) of the ink composition used in the ejection step is preferably 7.5 to 9.5 (more preferably 8.0 to 9.0). Among these, in the present invention, from the viewpoint of image density, resolution, and speedup of inkjet recording, the pH (25 ° C.) of the ink composition is 7.5 or more, and the pH (25 ° C.) of the treatment liquid is. The case of 1.5-3 is preferable. The aggregating components can be used alone or in combination of two or more.

  The treatment liquid can be configured using at least one acidic compound as an aggregation component. As the acidic compound, a compound having a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid group, or a carboxyl group, or a salt thereof (for example, a polyvalent metal salt) may be used. it can. Among these, from the viewpoint of the aggregation rate of the ink composition, a compound having a phosphate group or a carboxyl group is more preferable, and a compound having a carboxyl group is still more preferable.

  The compound having a carboxyl group includes polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphoric acid. , Pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof (for example, polyvalent metal salts), etc. It is preferable to be selected from among These compounds may be used alone or in combination of two or more.

The treatment liquid in the present invention can be configured to further contain an aqueous solvent (for example, water) in addition to the acidic compound.
As content in the processing liquid of an acidic compound, it is preferable that it is 5-95 mass% with respect to the total mass of a processing liquid from a viewpoint of the aggregation effect, and it is more preferable that it is 10-80 mass%. More preferably, it is 15-50 mass%, Most preferably, it is 18-30%.

  Moreover, the process liquid which added the polyvalent metal salt is mentioned, and high-speed aggregation property can be improved. Examples of the polyvalent metal salt include alkaline earth metals belonging to Group 2 of the periodic table (eg, magnesium, calcium), transition metals belonging to Group 3 of the periodic table (eg, lanthanum), and cations from Group 13 of the periodic table. (For example, aluminum) and the salt of lanthanides (for example, neodymium) can be mentioned. As the metal salt, carboxylate (formic acid, acetic acid, benzoate, etc.), nitrate, chloride, and thiocyanate are suitable. Among them, preferred are calcium salts or magnesium salts of carboxylic acids (formic acid, acetic acid, benzoates, etc.), calcium salts or magnesium salts of nitric acid, calcium chloride, magnesium chloride, and calcium salts or magnesium salts of thiocyanic acid.

  The content of the metal salt in the treatment liquid is preferably 1 to 10% by mass, more preferably 1.5 to 7% by mass, and still more preferably 2 to 6% by mass from the viewpoint of the aggregation effect. It is.

  Moreover, a process liquid can be comprised using at least 1 sort (s) of a cationic organic compound as an aggregation component. Examples of the cationic organic compound include poly (vinyl pyridine) salt, polyalkylaminoethyl acrylate, polyalkylaminoethyl methacrylate, poly (vinyl imidazole), polyethyleneimine, polybiguanide, polyguanide, and polyallylamine and derivatives thereof. Mention may be made of cationic polymers.

  The weight average molecular weight of the cationic polymer is preferably smaller in terms of the viscosity of the treatment liquid. When the treatment liquid is applied to the recording medium by an ink jet method, the range of 1,000 to 500,000 is preferable, the range of 1,500 to 200,000 is more preferable, and still more preferably 2,000 to 100,000. Range. When the weight average molecular weight is 1000 or more, it is advantageous from the viewpoint of the aggregation rate, and when it is 500,000 or less, it is advantageous from the viewpoint of ejection reliability. However, this is not the case when the treatment liquid is applied to the recording medium by a method other than inkjet.

Furthermore, as the cationic organic compound, for example, a primary, secondary, or tertiary amine salt type compound is preferable. Examples of the amine salt type compounds include compounds such as hydrochloride or acetate (for example, laurylamine, cocoamine, stearylamine, rosinamine), quaternary ammonium salt type compounds (for example, lauryltrimethylammonium chloride, cetyltrimethyl). Ammonium chloride, lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, etc.), pyridinium salt type compounds (eg, cetylpyridinium chloride, cetylpyridinium bromide, etc.), imidazoline type cationic compounds (eg, 2-heptadecenyl- Hydroxyethyl imidazoline etc.), ethylene oxide adducts of higher alkylamines (eg dihydroxyethyl stearylamine etc.), etc. Cationic compounds, for example, amino acid type amphoteric surfactants, carboxylate type amphoteric surfactants (eg stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, etc.), sulfate ester type, sulfonic acid type, or phosphate ester type And amphoteric surfactants that exhibit a cationic property in a desired pH range.
Of these, divalent or higher cationic organic compounds are preferred.

  As content in the processing liquid of a cationic organic compound, 1-50 mass% is preferable from a viewpoint of the aggregation effect, More preferably, it is 2-30 mass%.

  Among the above, the aggregating component is preferably a divalent or higher carboxylic acid or a divalent or higher cationic organic compound from the viewpoint of aggregability and image scratch resistance.

  The viscosity of the treatment liquid is preferably in the range of 1 to 30 mPa · s, more preferably in the range of 1 to 20 mPa · s, still more preferably in the range of 2 to 15 mPa · s, from the viewpoint of the aggregation rate of the ink composition. The range of 10 mPa · s is particularly preferable. The viscosity is measured under a condition of 20 ° C. using VISCOMETER TV-22 (manufactured by TOKI SANGYO CO. LTD).

  The surface tension of the treatment liquid is preferably 20 to 60 mN / m, more preferably 20 to 45 mN / m, and more preferably 25 to 40 mN / m from the viewpoint of the aggregation rate of the ink composition. More preferably. The surface tension is measured under conditions of 25 ° C. using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

  The treatment liquid in the present invention can generally contain a water-soluble organic solvent in addition to the aggregating component, and can be constituted using other various additives within a range not impairing the effects of the present invention. The details of the water-soluble organic solvent are the same as those in the ink composition described above.

  Examples of the other additives include a drying inhibitor (wetting agent), an antifading agent, an emulsion stabilizer, a penetration accelerator, an ultraviolet absorber, an antiseptic, an antifungal agent, a pH adjuster, a surface tension adjuster, Known additives such as antifoaming agents, viscosity modifiers, dispersants, dispersion stabilizers, rust preventives, chelating agents are listed, and specific examples of other additives included in the ink composition described above The listed ones are applicable.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “parts” are based on mass.
The weight average molecular weight was measured by gel permeation chromatography (GPC). GPC uses HLC-8220GPC (manufactured by Tosoh Corporation), and as a column, TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, TSKgeL SuperHZ2000 (both trade names made by Tosoh Corporation) are connected in series. THF (tetrahydrofuran) was used as an eluent. The conditions were as follows: the sample concentration was 0.45 mass%, the flow rate was 0.35 ml / min, the sample injection amount was 10 μl, the measurement temperature was 40 ° C., and the RI detector was used. In addition, the calibration curve is “standard sample TSK standard, polystyrene” manufactured by Tosoh Corporation: “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, It produced from eight samples of "A-2500", "A-1000", and "n-propylbenzene". The acid value was determined by the method described in JIS standard (JIS K0070: 1992).

<Ink composition>
(Composition of cyan ink C1)
Cyan ink C1 was prepared so as to have the following composition.
Cyan pigment (Pigment Blue 15: 3): 4% by mass
Acrylic polymer dispersant (acid value 65.2 mgKOH / g, weight average molecular weight 44600): 2% by mass
Aqueous dispersion of acrylic polymer particles (solid content 28% by mass, weight average molecular weight 66000): 14% by mass
・ Sanix GP250: 10% by mass
(Sanyo Chemical Industries, water-soluble organic solvent)
Tripropylene glycol monoethyl ether: 10% by mass
(Wako Pure Chemical Industries, water-soluble organic solvent)
・ Orphine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 1% by mass
・ Microcrystalline wax (HI-MIC1090 manufactured by Nippon Seiwa Co., Ltd.)
: 2% by mass
Ion exchange water was added to the above components to adjust to 100% by mass.

(Composition of magenta ink M1)
The composition was the same as that of cyan ink C1, except that the cyan pigment in the composition of cyan ink C1 was changed to a magenta pigment (Pigment Red 122) so that the amount of the pigment was the same.

(Composition of yellow ink Y1)
The composition was the same as that of the cyan ink C1 except that the cyan pigment in the composition of the cyan ink C1 was changed to a yellow pigment (Pigment Yellow 74) so that the amount of the pigment was the same.

(Composition of black ink K1)
The composition was the same as that of the cyan ink C1 except that the cyan pigment in the composition of the cyan ink C1 was changed to a black pigment (carbon black) so that the amount of the pigment was the same.

<Preparation of treatment solution>
Each component was mixed so that it might become the following composition, and the process liquid was prepared.
Malonic acid (divalent carboxylic acid, manufactured by Wako Pure Chemical Industries, Ltd.) 15.0% by mass
・ Diethylene glycol monomethyl ether (Wako Pure Chemical Industries, Ltd.) 20.0% by mass
・ N-oleoyl-N-methyl taurine sodium (surfactant) 1.0% by mass
・ Ion-exchanged water 64.0% by mass

The physical properties of the treatment liquid were a viscosity of 2.6 mPa · s, a surface tension of 37.3 mN / m, and a pH of 1.6. The surface tension was measured using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) under the condition of 25 ° C. by the Wilhelmi method using a platinum plate. The viscosity was measured using a VISCOMETER TV-22 (manufactured by TOKI SANGYO CO. LTD) at 30 ° C. The pH was measured at 25 ° C. with the stock solution using a pH meter WM-50EG manufactured by Toa DKK Co., Ltd.
The volume average particle diameter was measured with a nanotrack particle size distribution measuring apparatus UPA-EX150 (manufactured by Nikkiso Co., Ltd.). The measurement was performed by adding 10 ml of ion-exchanged water to 100 μl of a 20% by mass inorganic particle aqueous dispersion to prepare a sample solution for measurement, and adjusting the temperature to 25 ° C.

-Production of web member 1-
Silicone oil (“KF-96-100cs”, manufactured by Shin-Etsu Chemical Co., Ltd., boiling point 150 ° C. or higher, SP value 10 or lower) 85.0% by mass
Silica particles (manufactured by SUNJIN CHEMICAL, SUNSIL130L, volume average particle size 7.5 μm) 15.0% by mass

1 L of the liquid having the above composition was mixed with a silverson emulsifier at 5000 rpm for 60 minutes to prepare inorganic particle dispersion 1. The web member 1 was produced by impregnating the inorganic particle dispersion 1 into a nonwoven fabric so as to be 30 g / m ² . The nonwoven fabric was a mixed material of polyamide and polyester, and had a weight of 30 g / m ² and a thickness of 0.1 mm.

-Production of web member 2-
It was produced in the same manner as the web member 1 except that calcium carbonate (volume average particle size 8.0 μm) was used in place of the silica particles in the inorganic particle dispersion 1.

-Production of web member 3-
It was produced in the same manner as the web member 1 except that alumina (volume average particle size 10.0 μm) was used in place of the silica particles in the inorganic particle dispersion 1.

-Production of web member 4-
It was produced in the same manner as the web member 1 except that the silica particles were removed from the inorganic particle dispersion 1.

-Production of web member 5-
The inorganic particle dispersion 1 was prepared in the same manner as the web member 1 except that silica particles (volume average particle size 0.54 μm) were used instead of silica particles (volume average particle size 7.5 μm).

-Production of web member 6-
Liquid paraffin (manufactured by Sanko Chemical Co., Ltd., “liquid paraffin 260-S”, density (15 ° C.) 0.866 g / cm ³ , boiling point 150 ° C. or higher, SP value 10 instead of silicone oil in the inorganic particle dispersion 1 It was produced in the same manner as the web member 1 except that the following was used.

-Production of web member 7-
The inorganic particle dispersion 1 was prepared in the same manner as the web member 1 except that glycerin (boiling point 290 ° C., SP value 40.97) was used instead of silicone oil.

-Production of web member 8-
The inorganic particle dispersion 1 was prepared in the same manner as the web member 1 except that isopropyl alcohol (IPA, boiling point 82.4 ° C.) was used instead of silicone oil.

-Production of web member 9-
In the inorganic particle dispersion 1, the hydrophobized silica particles (manufactured by Cabot, “CAB-O-SIL TG-820F”, volume average particle size 10.0 μm) were used in place of the silica particles. It produced similarly. The hydrophobized silica is obtained by surface-treating silica particles with a silane coupling agent composed of hexamethyldisilane and cyclic silazane.

<Image recording and evaluation>
As shown below, an image was recorded using ink C1 / M1 / Y1 / K1, and the following evaluation was performed. The evaluation results are shown in Table 1 below.

-Abrasion resistance-
A GELJET GX5000 printer head (full line head manufactured by Ricoh) was prepared, and the storage tank connected thereto was refilled with the cyan ink C1, the magenta ink M1, the yellow ink Y1, and the black ink K1 obtained above. Tokishi Art Double-sided N (Mitsubishi Paper Co., Ltd.) as a recording medium is fixed on a stage (conveyor belt) that can move in a predetermined linear direction at 500 mm / second, and the reaction solution obtained above is wired to it. It was applied with a bar coater to a thickness of about 1.5 μm (corresponding to 0.34 g / m 2 of malonic acid), and dried immediately at 50 ° C. for 2 seconds (FIG. 2).
Thereafter, when the GELJET GX5000 printer head (full line head manufactured by Ricoh Co., Ltd.) is orthogonal to the direction of movement of the stage (sub-scanning direction), the direction of the line head in which the nozzles are aligned (main scanning direction) is 75. It is fixedly arranged so as to incline by 7 °, and the recording medium is ejected by a line method under the ejection conditions of an ink droplet amount of 3.5 pL, an ejection frequency of 24 kHz, and a resolution of 1200 dpi × 600 dpi while moving at a constant speed in the sub-scanning direction. An image was printed to obtain an evaluation sample. Immediately after printing, it was dried at 60 ° C. for 3 seconds.

Next, by changing the web member installed as shown in FIG. 2 in accordance with each evaluation (Table 1 below), and passing between a pair of rollers heated to 60 ° C. (heating roller and pressure roller), A fixing process was performed at a nip pressure of 0.25 MPa and a nip width of 4 mm to obtain an evaluation sample.
The heating roller (fixing roller) shown in FIG. 2 is a SUS cylindrical core whose surface is covered with a silicone resin with a halogen lamp inside.

Unprinted special diamond art double-sided N cut to 10mm x 50mm is wrapped around a paperweight (weight 470g, size 15mm x 30mm x 120mm) (the area where the non-printed special diamond art double-sided N and the evaluation sample contact is 150mm ² ) The evaluation sample prepared above was rubbed 3 times (corresponding to a load of 260 kg / m ² ). The printed surface after rubbing was visually observed and evaluated according to the following evaluation criteria.

<Evaluation criteria>
3: No peeling of the image on the printed surface was visible.
2: Peeling of the image on the printed surface was slightly visible, but at a level where there was no practical problem.
1: The peeling of the image on the printing surface was visually recognized, and there was a problem in practical use.

-Blocking evaluation-
A solid image was produced in the same manner as the abrasion resistance. Two evaluation samples were cut into a size of 4 cm × 4 cm, bonded so that the recording surfaces overlap each other, and a pressure of 2.0 MPa was applied for 30 seconds with a press to peel off the evaluation sample. The ease of peeling at this time and the color transfer after peeling were visually observed and evaluated according to the following evaluation criteria.

<Evaluation criteria>
3: Peeled naturally and no color transfer to each other's paper.
2: Sticking occurred and some color transfer to each other's paper was observed.
1: Sticking was strong, and many colors were transferred to each other's paper.

-Fixing offset-
In the evaluation of rubbing resistance, the solid ink was output in the same manner as the rubbing resistance evaluation except that the solid ink was adjusted to 7.0 pL. At this time, peeling of the image part due to transfer of the image to the fixing roller was visually observed and evaluated according to the following evaluation criteria.
<Evaluation criteria>
3: No peeling of the image on the printed surface was visible.
2: A slight peeling of the image on the printed surface was visually recognized, but there was no practical problem.
1: A level where there is a problem in practical use because the peeling of the image on the printing surface can be visually recognized.

-Variation evaluation-
The web member 1 and the web member 9 are prepared for each 10 samples, the web member 1-1, the web member 1-2, the web member 1-3,..., The web member 1-10,. 1 to web members 9-10. The blocking evaluation was performed on each member, and the average score of 10 samples was calculated. The results are shown in Table 2.

  As can be seen from Table 1, according to the ink jet forming method of the present invention, it is possible to produce a printed material having good abrasion resistance with improved fixing offset and suppressed blocking. Further, as apparent from Table 2, it can be seen that when the inorganic particles are changed to hydrophobic inorganic particles, the performance variation (particularly, the variation in blocking reduction effect) of the obtained printed matter can be further suppressed.

DESCRIPTION OF SYMBOLS 1 Heating roller 2 Sending roller 3 Web press roller 4 Winding roller 5 Cloth material (web member)
6 Pressure roller 10 Conveying belt 11 Recording medium 12 Treatment liquid application unit 13 Treatment liquid application bar 14 Heating and drying unit 15 Dryer 16 Inkjet recording unit 17 Inkjet nozzle

Claims (6)

A recording step of recording an image on a recording medium by an inkjet method, and an applying step of applying inorganic particles having a particle size of 1 μm or more contained in a non-volatile solvent on the recorded image;
An inkjet image forming method comprising:   The inkjet image forming method according to claim 1, wherein the inorganic particles include at least one inorganic compound selected from the group consisting of silica, calcium carbonate, alumina, zirconia, and titanium oxide.   The inkjet image forming method according to claim 1, wherein the inorganic particles are subjected to a hydrophobic treatment on the surface of the inorganic particles.   The inkjet image forming method according to claim 1, wherein the nonvolatile solvent is silicone oil or liquid paraffin.   The inkjet image forming method according to any one of claims 1 to 4, further comprising a fixing step of fixing an image recorded by an inkjet method after the applying step.   The inkjet image forming method according to claim 1, wherein the applying step is a step of applying a non-volatile solvent containing the inorganic particles to a roller surface and bringing the roller into contact with the recording medium. .