JP4878247B2 - Inkjet recording method and inkjet recording apparatus - Google Patents

Description

  The present invention relates to an inkjet recording method and an inkjet recording apparatus capable of recording a high-quality image close to commercial printing such as offset printing by an inkjet method.

Inkjet recording is known as an excellent recording method that does not select a recording medium (media), and research and development on a recording apparatus, a recording method, a recording material, and the like are actively performed.
In recent years, with the widespread use of printers, high definition and high speed, image quality close to that of silver halide photography can be easily obtained. This is because not only the evolution of the printer but also various improvements have been made to achieve high image quality of ink and media. In particular, the evolution of media has been remarkable, and the current media, developed to increase gloss of ink while increasing the ink absorption rate and absorption amount, surpasses conventional commercial printing in terms of gloss and quality. Has developed. Such ink jet recording media can be broadly classified into a swelling type and a void type, but recently, a void type that is excellent in ink drying speed has become mainstream.

As the void-type media, for example, a coating liquid in which silica and alumina hydrate are dispersed is applied on a substrate to form an ink absorption layer having voids for taking in ink, and a porous material containing colloidal silica as necessary. Those having a quality gloss layer have been proposed (see, for example, Patent Document 1 and Patent Document 2). These proposed media are excellent in ink absorptivity and provide high-definition images, and are therefore suitable for consumer photo output applications and the like. On the other hand, this type of media is very expensive compared to the coated paper for general commercial printing and publication printing because the raw materials are expensive and the manufacturing process is complicated. For this reason, although the images are of high quality, they are rarely used in the commercial printing field that requires a large amount of inexpensive output such as leaflets, catalogs, and brochures. Therefore, conventionally, various means for reducing the cost of the void type media have been tried.
However, as the filler contained in the ink absorption layer, the transparency of the ink absorption layer can be kept high, and it is necessary to use a material having a large oil absorption (specific surface area). For example, silica, alumina hydrate, A specific expensive filler such as colloidal silica must be used in a large amount, and it is difficult to reduce the price.

  On the other hand, there is an inexpensive coated paper using a large amount of inexpensive and high concealing fillers such as calcium carbonate and kaolin as a coating layer material, such as coated paper for commercial printing and publication printing. However, when such coated paper is used for ink jet media, the ink cannot be absorbed in time, the image is smeared, and the color material in the ink that has soaked into the ink absorbing layer is concealed by a highly concealing filler such as kaolin. Therefore, there is a problem that the concentration cannot be expressed. In fact, when ink jet recording with dye ink on commercial and publishing coated papers using highly concealing fillers, only the color material present near the surface layer is concentrated even if the amount of ink is increased. Therefore, it has been considered that coated paper is not suitable for ink jet recording.

  In recent years, a pigment ink using a pigment as a colorant (coloring material) has attracted attention. Since pigments are insoluble in water, it is common to use fine particles dispersed in a solvent. Pigment inks are water-based pigments in which the pigment is dispersed in water from the viewpoint of safety and the like. Ink is the mainstream. Such water-based pigment inks tend to cause aggregation and precipitation of pigment particles compared to dye inks, and in order to obtain long-term storage stability similar to dye inks, it is necessary to adjust dispersion conditions and add additives. In addition, it is difficult to use a thermal head because a dispersion stabilizer or the like causes kogation, and the colorimetric range of the colorant is inferior to that of the dye. However, pigment inks have been attracting much attention because of their high black density and high print quality, storage stability after recording, and water resistance.

In an inkjet printer using such a pigment ink, the colorant of the ink may be close to the colorant of a general commercial printing ink, and it is considered that the texture of the printed matter can be brought close to commercial printing. However, when the conventional pigment ink is actually recorded on coated paper for commercial printing and publication printing, there is a problem that the ink cannot be absorbed in time and the image is blurred or the pigment is not fixed at all after drying. This is because the design philosophy of ink jet recording is not different from the philosophy of using dye ink, the pigment is only considered as a dye with high light resistance, and the features of the pigment ink are not considered. It is done.
In addition, research and development has been actively conducted on media compatible with pigment inks. For example, in Patent Document 3, in order to produce image gloss while accelerating ink absorption, a method for developing gloss while increasing the porosity of the media surface is being sought on the extension of the prior art using expensive materials. .

  On the other hand, one of the major problems in inkjet recording is to increase the recording speed. Increasing the recording speed is an important point for reducing the recording cost. Possible means include (1) means for increasing the size of the head and expanding the recording area per scan, and (2) the structure of the head. , Means to increase the ink ejection speed and head scanning speed while maintaining the ink droplet size and resolution, and (3) the ink ejection speed and the head structure are not changed, but the ink droplet size (volume) is not changed. There are means for reducing the number of pixels by increasing the size, and increasing the scanning speed to perform high-speed drawing.

  The means (1) requires a large change in the head and system, and tends to increase the printer price, but it is easy to maintain the image quality. Further, the means (2) can be performed without increasing the cost of the apparatus as compared with the means (1), but there is a limit on the device such as the drive frequency, and a dramatic increase in speed cannot be expected. The means (3) is relatively simple and inexpensive, but the image quality is often greatly deteriorated. For example, when using two small droplets to draw a dot, the dot area is almost doubled compared to one small droplet, but when the droplet size is doubled, the dot area is not doubled. This is because there are many cases. This phenomenon in which the droplet size and the dot area are not proportional is particularly noticeable when ink having poor wetting and spreading is used. When an image is recorded by using the means (3), it is recognized as deterioration of filling or occurrence of banding. It is often done. Further, when the filling or banding is improved by means of (3) above, it is necessary to draw with a larger droplet size, and the filling is improved, but on the contrary, beading or character bleeding due to ink absorption failure occurs. This problem occurs. In particular, in the case of an ink jet recording method using a recording medium having a barrier coating layer and a water-dispersible colorant, it is necessary to strictly limit the upper limit of the ink adhesion amount. It is difficult to increase the speed.

  As described above, in the prior art documents, the purpose is to prevent ink bleeding, and most of the attempts have been made to improve the fixability, and the size of the medium is too good for ink absorption and too good for ink diffusion. Is. In addition, there is an example in which pretreatment is performed on a medium having poor ink absorbability. In this case, an ink receiving layer excellent in ink absorption and fixing is newly provided on the surface of the medium. In both cases, a treatment liquid that causes a certain kind of reaction with ink is applied, and since it is a means of improving the image quality by a chemical reaction, the amount of treatment liquid applied increases, and drying is required before printing. Currently, there are various problems to be solved, such as inferior stability of the processing liquid itself for prompt reaction, and the necessity of energy such as heat and light for fixing.

JP 2005-212327 A Japanese Patent Application Laid-Open No. 11-078225 JP 2001-347749 A

  An object of the present invention is to solve the conventional problems in response to the above-mentioned demands and achieve the following object. That is, the present invention provides a high-quality ink recording material having a texture close to that of a commercial printed material having a wide paper compatibility, capable of full-color image recording, and high image density and excellent image uniformity, compared to the conventional case. An object is to provide an ideal ink jet recording method and ink jet recording apparatus capable of recording at high speed and low cost.

As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, the present inventors have made extensive studies on a low-cost and high-speed inkjet recording method. As a result, a pigment ink having high permeability and a recording medium having low ink absorption It was found that a low-cost and high-speed inkjet recording method based on a new design concept can be achieved by performing specific pretreatment on the recording medium to control the wetting and spreading of ink droplets.
That is, when recording is performed using a small amount of ultra-high-penetration pigment ink on a recording medium in which ink absorption (penetration) is suppressed so that the pigment in the ink does not penetrate as much as possible, the recording medium contains a surfactant. It has been found that by applying a liquid and pre-treating, the ink can be spread and wetting can be promoted, and a sufficient dot size can be realized even if the droplet size is increased. In addition, we found that even if the number of pixels was reduced by increasing the ink droplets under a certain maximum amount of ink, the embedding and banding did not deteriorate as before, and high-quality and high-speed recording was possible. .
Further, even if a conventional recording medium with small dot spreading and poor embedding is used as long as it functions as a barrier coating layer, the ink jet recording method of the present invention can improve ink wetting and spreading. It was found that the compatibility was improved.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> a pretreatment step of performing pretreatment by applying a pretreatment liquid containing at least a surfactant to a recording medium having at least one barrier coating layer on at least one surface of a support;
An ink jet recording method comprising at least an ink flying step of applying a stimulus to an ink containing at least a water dispersible colorant and causing the ink to fly to record an image on a pretreated recording medium. .
<2> The inkjet recording method according to <1>, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.
<3> The recording medium has a pure water transfer amount of 35 ml / m ² or less at a contact time of 100 ms measured by a dynamic scanning absorption meter, and a pure water transfer amount of 40 ml / m ² or less at a contact time of 400 ms. The inkjet recording method according to any one of <1> to <2>.
<4> The inkjet according to any one of <1> to <3>, wherein a contact angle by a droplet dropping method of ink on a recording medium after pretreatment is 15 ° to 35 ° after 5 seconds of ink dropping. It is a recording method.
<5> The inkjet recording method according to any one of <1> to <4>, wherein the pretreatment liquid is applied by bringing the pretreatment means into contact with the recording medium.
<6> The inkjet recording method according to <5>, wherein the pretreatment unit is a roller.
<7> Any one of <1> to <6>, wherein any one of an ink having a droplet size of 20 pl or more and a combination of an ink having a droplet size of 20 pl or more and an ink having a droplet size of less than 20 pl is used. The inkjet recording method described.
<8> The inkjet recording method according to any one of <1> to <7>, wherein the maximum adhesion amount of the ink is 15 g / m ² or less.
<9> The water dispersible colorant is any one of a pigment and colored fine particles, and the volume average particle diameter of the colorant is 0.01 to 0.16 μm. The inkjet recording method described.
<10> The inkjet recording method according to any one of <1> to <9>, wherein the ink has a viscosity at 25 ° C. of 3 mPa · s or more.
<11> The ink jet recording method according to any one of <1> to <10>, wherein the ink includes a penetrant, and the penetrant is any one of a polyol compound having 8 or more carbon atoms and a glycol ether compound. is there.
<12> The <11>, wherein the polyol compound having 8 or more carbon atoms is at least one of 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. Inkjet recording method.
<13> The ink contains a surfactant, and the surfactant is at least selected from the following general formulas (I), (II), (III), (IV), (V), and (VI) The inkjet recording method according to any one of <1> to <12>, which is one type.
R ¹ —O— (CH ₂ CH ₂ O) _h CH ₂ COOM —General Formula (I)
In the general formula (I), ^{R 1} represents an alkyl group. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.
In the general formula (II), ^{R 2} represents an alkyl group. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.
In the general formula (III), ^{R 3} is represents a hydrocarbon group. k represents an integer of 5 to 20.
_{^{R 4 - (OCH 2 CH 2}} ) j OH ··· formula (IV)
In the general formula (IV), ^{R 4} represents a hydrocarbon group. j represents an integer of 5 to 20.
In the general formula (V), ^{R 6} represents a hydrocarbon group. L and p each represent an integer of 1 to 20.
However, in said general formula (VI), q and r represent the integer of 0-40, respectively.
<14> The inkjet according to any one of <1> to <13>, wherein the ink contains a wetting agent, and the wetting agent is at least one selected from a polyol compound, a lactam compound, a urea compound, and a saccharide. It is a recording method.
<15> The polyol compound is glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 1,2,4-butane The inkjet recording method according to <14>, which is at least one selected from triol, 1,2,6-hexanetriol, thiodiglycol, pentaerythritol, trimethylolethane, and trimethylolpropane.
<16> Any of the above <14> to <15>, wherein the lactam compound is at least one selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and ε-caprolactam The ink jet recording method according to claim 1.
<17> The inkjet according to any one of <14> to <16>, wherein the urea compound is at least one selected from urea, thiourea, ethyleneurea, and 1,3-dimethyl-2-imidazolidinone. It is a recording method.
<18> The inkjet recording method according to any one of <14> to <17>, wherein the saccharide is at least one selected from maltose, sorbitol, gluconolactone, and maltose.
<19> The inkjet recording method according to any one of <14> to <18>, wherein the content of the wetting agent in the ink is 10 to 50% by mass.
<20> The inkjet recording method according to any one of <1> to <19>, wherein the ink is at least one selected from cyan ink, magenta ink, yellow ink, and black ink.
<21> a recording medium having a support and at least one barrier coating layer on at least one surface of the support;
Pretreatment means for pretreating the recording medium by applying a pretreatment liquid containing at least a surfactant;
An ink jet recording apparatus comprising at least ink flying means for applying a stimulus to ink containing at least a water dispersible colorant and causing the ink to fly to record an image on a pretreated recording medium. .

  The ink jet recording method of the present invention includes a pretreatment process and an ink flying process. In the pretreatment step, the recording medium having at least one barrier coating layer on at least one surface of the support is pretreated by applying a pretreatment liquid containing at least a surfactant. In the ink flying step, a stimulus is applied to the ink containing at least the water-dispersible colorant, and the ink is caused to fly to record an image on a pre-processed recording medium. As a result, full-color image recording is possible with wide paper compatibility, and high-quality ink recordings with a high image density and excellent image uniformity and a texture similar to commercial printed materials are much faster and cheaper than before. Can be recorded.

  The ink jet recording apparatus of the present invention includes a recording medium, a preprocessing unit, and an ink flying unit. The recording medium has a support and at least one barrier coating layer on at least one surface of the support. The pretreatment means performs pretreatment by applying a pretreatment liquid containing at least a surfactant to the recording medium. The ink flying means applies a stimulus to ink containing at least a water-dispersible colorant, and causes the ink to fly to record an image on a pre-processed recording medium. As a result, full-color image recording is possible with wide paper compatibility, and high-quality ink recordings with a high image density and excellent image uniformity and a texture similar to commercial printed materials are much faster and cheaper than before. Can be recorded.

  According to the present invention, conventional problems can be solved, paper compatibility is wide, full-color image recording is possible, high-quality ink recording with high image density and excellent image uniformity and texture similar to commercial printed matter. It is possible to provide an ideal ink jet recording method and ink jet recording apparatus capable of recording a product at a much higher speed and lower cost than conventional ones.

(Inkjet recording method and inkjet recording apparatus)
The ink jet recording method of the present invention includes at least a pretreatment step and an ink flying step, and further includes other steps such as a control step as necessary.
The ink jet recording apparatus of the present invention includes at least a recording medium, a preprocessing unit, and an ink flying unit, and further includes other units such as a control unit as necessary.

  The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, the pretreatment step can be suitably carried out by the pretreatment means, and the ink flying step can be carried out by the ink flying means. It can be suitably performed. Moreover, the said other process can be suitably performed by the said other means.

<Pretreatment process and pretreatment means>
The pretreatment step is a step of performing pretreatment by applying a pretreatment liquid containing at least a surfactant to a recording medium having at least one barrier coating layer on at least one surface of a support. , Is performed by the pre-processing means.

〔recoding media〕
The recording medium includes a support and at least one barrier coating layer on at least one surface of the support, and further includes other layers as necessary.

The recording medium is transferred amount of pure water of the recording medium at a contact time of 100ms measured by a dynamic scanning absorptometer is preferably 35 ml / ^{m 2} or less, and more preferably 3~30ml / ^{m 2.} Further, the transfer amount of pure water to the recording medium at a contact time of 400 ms is preferably 40 ml / m ² or less, more preferably ² to 35 ml / m ² . The barrier coating layer of the recording medium satisfying this condition can be regarded as having a barrier function, and when combined with the ink, the so-called “cut” is good. A recorded image having a high optical density (OD) can be obtained. If the transfer amount is larger than this, the colorant may penetrate into the barrier coating layer and / or the support, and the colorant is concealed in the pigment of the barrier coating layer, resulting in a high-density image. I can't.

  Here, the dynamic scanning absorptiometer (DSA, Papa-Pagi Technical Journal, Vol. 48, May 1994, pp. 88-92, Kuju Shigenori) absorbs liquid in a very short time. It is a device that can measure accurately. The dynamic scanning absorption meter reads the liquid absorption speed directly from the movement of the meniscus in the capillary, makes the sample a disk, and then scans the liquid absorption head in a spiral shape, and the scanning speed according to a preset pattern. Is automatically changed by a method in which the number of necessary points is measured with one sample. A liquid supply head for a paper sample is connected to a capillary via a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, the transfer amount of pure water was measured using a dynamic scanning absorption meter (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.). The transfer amount at the contact time of 100 ms and the contact time of 400 ms can be obtained by interpolation from the measured value of the transfer amount at the contact time adjacent to each contact time.

  It was found that the contact angle of the media surface by applying the pretreatment liquid has a great influence on the image quality. The pretreatment is effective not only for large droplets having an ink droplet size of about 20 pl, but also for medium droplets of about 10 pl and small droplets of about 2 pl, and the image quality can be greatly improved.

The contact angle by the ink droplet dropping method on the recording medium after the pretreatment is preferably 15 ° or more and 35 ° or less, and more preferably 15 to 30 °. By setting the contact angle to 35 ° or less, effective wetting and spreading of ink droplets on the medium occurs, the dot diameter can be increased, and a uniform image with good filling can be obtained. Even if the resolution is reduced by using large droplets, it is possible to maintain the goodness of filling, and a sharp image can be obtained.
On the other hand, it is preferable that the dots spread out in a perfect circle shape, and it has been found that when the dots expand to an irregular shape, blurring of the outline and degradation of resolution occur. For this reason, by setting the contact angle between the pre-treated media and the ink to be 15 ° or more, irregular wetting and spreading can be prevented, and irregular dots can be prevented from being generated. A balance of image feeling can be achieved.
Here, as the contact angle, a generally known contact angle measurement method using a droplet dropping method can be used. Can be measured by dropping 3 μL from the microsyringe and determining the value of the contact angle after 5 seconds from dropping.

-Support-
The support is not particularly limited and may be appropriately selected depending on the intended purpose.However, a mixture of chemical pulp, mechanical pulp, recovered paper recovered pulp, etc., at an arbitrary ratio is used. Depending on the material, paper is made with a long mesh former, gap type twin wire former, and a hybrid former with the latter half of the long mesh part made of twin wire. Is used.

  Examples of the pulp include virgin chemical pulp (CP), for example, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp, softwood unbleached kraft pulp, hardwood bleached sulfite pulp, softwood bleached Wood such as sulfite pulp, hardwood unbleached sulfite pulp, and softwood unbleached sulfite pulp is used, and virgin chemical pulp, virgin mechanical pulp (MP ), For example, virgin mechanical pulp produced mainly by mechanically treating wood such as ground pulp, chemiground pulp, chemimechanical pulp, semi-chemical pulp, or other fiber raw materials may be included. .

  As a raw material of the waste paper pulp, as shown in the waste paper standard quality specification table of the waste paper recycling promotion center, for example, white, ruled white, cream white, card, white, medium white, imitation, fair white, Kent, White art, special upper limit, another upper limit, newspaper, magazine, etc. are listed. Specifically, printer paper such as non-coating computer paper, thermal paper, and pressure-sensitive paper as information-related paper; OA waste paper such as PPC paper; coating of art paper, coated paper, finely coated paper, matte paper, etc. Paper: High quality paper, color quality, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, reprint paper, super paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Examples of used paper and paperboard include chemical pulp paper and high-yield pulp-containing paper. These may be used individually by 1 type and may use 2 or more types together.

The waste paper pulp is generally produced from a combination of the following four steps.
(1) For disaggregation, waste paper is treated with mechanical force and chemicals with a pulper to loosen it into a fibrous form, and the printing ink is peeled off from the fiber.
(2) Dust removal is to remove foreign matter (plastic etc.) and dust contained in waste paper with a screen, cleaner or the like.
(3) In the deinking, the printing ink peeled off from the fiber using a surfactant is removed from the system by a flotation method or a cleaning method.
(4) Bleaching increases the whiteness of the fiber using an oxidizing action or a reducing action.
When mixing the used paper pulp, the mixing ratio of the used paper pulp in the total pulp is preferably 40% or less from the viewpoint of curling after recording.

As a filler that can be used for the support, calcium carbonate is effective, but inorganic fillers such as kaolin, calcined clay, pyrophyllite, sericite, talc, and other inorganic fillers, satin white, barium sulfate, sulfuric acid, etc. Organic pigments such as calcium, zinc sulfide, plastic pigment and urea resin can also be used in combination.
The internal sizing agent used for the support is not particularly limited and may be appropriately selected according to the purpose. can do.
Examples of the internally added sizing agent include rosin emulsion sizing agents. Examples of the internally added sizing agent used for making the support include, for example, a neutral rosin sizing agent used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), petroleum resin Examples include sizing agents. Among these, a neutral rosin sizing agent or alkenyl succinic anhydride is particularly preferable.
The alkyl ketene dimer may be added in a small amount because of its high size effect, but the friction coefficient on the surface of the recording paper (media) is low and slippery, which is not preferable from the viewpoint of transportability during ink jet recording. There is.
The amount of the internal sizing agent used is not particularly limited and may be appropriately selected depending on the intended purpose.

  As the internal filler used for the support, for example, a conventionally known pigment is used as a white pigment. Examples of the white pigment include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide; styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin And organic pigments such as melamine resin. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular in the thickness of the said support body, Although it can select suitably according to the objective, 5-300 micrometers is preferable. The basis weight of the support is preferably 5 to 298 g / m ² .

-Barrier coating layer-
The barrier coating layer has a function of separating the pigment and the solvent in the ink and allowing only the solvent to penetrate into the substrate. Therefore, it is preferable that the barrier coating layer has a fine structure having pores (pores). If there is no fine structure in the barrier coating layer, the penetration of the solvent component in the ink is slowed, so that the phenomenon that the ink does not dry easily occurs. However, if there are too many fine structures, the function of separating the pigment in the ink will be reduced, the image density will decrease, or the pigment present on the surface of the recording medium after recording will migrate inside the media over time, and the color Cause change. If these conditions are satisfied, commercial printing paper and publication printing paper can be used as they are. By making the barrier coating layer resemble the appearance of a printing paper, it is possible to obtain a printed material that is close to the texture of a general commercial printed material.

  The barrier coating layer contains at least a pigment and a binder, and further contains other components as necessary.

-Pigment-
As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used.
Examples of the inorganic pigment include kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, Examples thereof include zinc hydroxide and chlorite. Among these, kaolin is particularly preferable because it has excellent glossiness and can be made close to a paper for offset printing.
The kaolin includes delaminated kaolin, calcined kaolin, engineered kaolin by surface modification, etc. In consideration of gloss expression, the particle size distribution is such that the proportion of particle size of 2 μm or less is 80% by mass or more. It is preferable that the kaolin which has occupies 50 mass% or more of the whole kaolin.
The amount of kaolin added is preferably 50 parts by mass or more with respect to 100 parts by mass of the binder. When the addition amount is less than 50 parts by mass, a sufficient effect on glossiness may not be obtained. The upper limit of the addition amount is not particularly limited, but is preferably 90 parts by mass or less from the viewpoint of coating suitability in consideration of the fluidity of kaolin, particularly the thickening under high shear force.

Examples of the organic pigment include water-soluble dispersions such as styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, and polyethylene particles. Two or more of these organic pigments may be mixed.
The addition amount of the organic pigment is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the total pigment in the barrier coating layer. Since the organic pigment is excellent in gloss expression and its specific gravity is smaller than that of the inorganic pigment, it is possible to obtain a barrier coating layer that is bulky, high gloss, and has good surface coverage. If the addition amount is less than 2 parts by mass, the above effect is not obtained. If the addition amount exceeds 20 parts by mass, the fluidity of the coating liquid is deteriorated, leading to a decrease in coating operability, and economical in terms of cost. Not right.
The organic pigment includes a solid type, a hollow type, a donut type, and the like in terms of its form, but the average particle size is 0.2 in view of the balance of gloss development, surface coverage, and fluidity of the coating liquid. A hollow mold having a porosity of 40% or more is more preferable.

-Binder-
The binder is not particularly limited and may be appropriately selected depending on the intended purpose. However, the binder and the pigment constituting the barrier coating layer have a strong adhesive force with the support and do not cause blocking. Is preferred.
Examples of the aqueous resin include polyvinyl alcohol; starches such as oxidized starch, esterified starch, enzyme-modified starch, and cationized starch; casein, soy protein; fiber derivatives such as carboxymethylcellulose and hydroxyethylcellulose; styrene-acrylic Examples thereof include resins, isobutylene-maleic anhydride resins, acrylic emulsions, vinyl acetate emulsions, vinylidene chloride emulsions, polyester emulsions, styrene-butadiene latexes, and acrylonitrile butadiene latexes. Among these, starch and styrene-butadiene latex are particularly preferable from the viewpoint of cost.
The styrene-butadiene latex is a copolymer generally used for paper coating, which contains styrene and butadiene as monomers and is copolymerized with other monomers as necessary, or the copolymer is modified by chemical reaction. Polymer latex is mentioned. Examples of the other monomer include acrylic acid, methacrylic acid, alkyl ester of acrylic acid or methacrylic acid, acrylonitrile, maleic acid, fumaric acid, vinyl acetate and the like. Further, it may contain a cross-linking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, isocyanate, etc., and a copolymer containing units such as N-methylolacrylamide and having a self-crosslinking property is used. Also good. These may be used individually by 1 type and may use 2 or more types together.

  The amount of the binder added to the barrier coating layer is preferably 50 to 70% by mass, more preferably 55 to 60% by mass, based on the solid content of the barrier coating layer. When the addition amount is too small, the adhesive strength is insufficient, and there is a concern that the strength of the barrier coating layer may be reduced, the internal bond strength may be reduced, and the powder may fall off.

  If necessary, a cationic organic compound can be added. Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, (Diallylamine hydrochloride / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate , Polyalkylene polyamine dicyandiamide ammonium salt condensate, dimethyl diallyl ammonium chloride, polydiallyl methylamine hydrochloride, poly (diallyl dimethyl ester) Ruammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine hydrochloride copolymer Products, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. These may be used individually by 1 type and may use 2 or more types together.

  In addition, other components can be added to the barrier coating layer as necessary, as long as the object and effect of the present invention are not impaired. As the other components, additives such as surfactants, dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, pH adjusting agents, preservatives, and antioxidants may be used.

There is no restriction | limiting in particular as said surfactant, According to the objective, it can select suitably, All use of anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant should be used. Can do. Among these, nonionic surfactants are particularly preferable.
Examples of the nonionic surfactant include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acids. Amide ethylene oxide adduct, fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol or sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol And fatty acid amides of alkanolamines. These may be used individually by 1 type and may use 2 or more types together.
The polyhydric alcohol is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include glycerol, trimethylolpropane, pentaerythritol, sorbitol, and sucrose. Moreover, about the ethylene oxide adduct, what substituted some alkylene oxides, such as propylene oxide or butylene oxide, in the range which can maintain water solubility is also effective. The substitution rate is preferably 50% or less. 4-15 are preferable and, as for HLB (hydrophilic lipophilic ratio) of the said nonionic surfactant, 7-13 are more preferable.

There is no restriction | limiting in particular as a formation method of the said barrier coating layer, Although it can select suitably according to the objective, For example, the method of apply | coating directly, What was once applied on the other base material is transcribe | transferred to a support body. Methods, spraying methods, and the like can be used.
Examples of the direct coating method include film transfer methods such as a roll coater method, an air knife coater method, a gate roll coater method, a size press method, a shim sizer method, and a rod metalring size press coater; a blade coater by a fountain or roll application Examples include methods.
The barrier coating layer can be dried using, for example, a hot air drying furnace, a hot drum, or the like. Furthermore, in order to smooth the surface or increase the strength of the surface, surface finishing may be performed with a calendar device (super calendar, soft calendar, gloss calendar, etc.).

There is no restriction | limiting in particular in the thickness of the said barrier coating layer, Although it can select suitably according to the objective, 30 micrometers or less are preferable and 0.5-25 micrometers is more preferable.
The barrier coating layer can be made very thin. At this time, in order to prevent the coloring agent from showing through (the color of the printed coloring agent can be seen through the back side), the barrier coating layer is used. Contrary to conventional ink jet media, it is necessary to contain a lot of inorganic pigments with high concealability in the layer. Therefore, the inorganic pigment in the barrier coating layer preferably has a lower amount of silica or alumina hydrate, which is a low concealing material used in conventional ink jet media, and is 15% by mass or less. More preferred. Thereby, even if the thickness of the barrier coating layer is reduced, the setback can be reduced and further cost reduction can be achieved.
If the amount of oil absorption is too high, such as alumina hydrate, the ink solvent will not easily move from the barrier coating layer to the substrate. Alumina hydrate that has absorbed a large amount of the solvent is not preferable because long-term storage causes image blur due to discoloration or pigment migration.

  The recording medium may have a back layer on the back surface of the support, and other layers may be formed between the support and the barrier coating layer and between the support and the back layer. Further, a protective layer can be provided on the barrier coating layer. Each of these layers may be a single layer or a plurality of layers.

As the recording medium, in addition to an inkjet recording medium, commercially available coated paper for offset printing, coated paper for gravure printing, and the like may be used.
Commercially available coated coated paper refers to cast coated paper, so-called art paper (A0 size, A1 size), A2 size coated paper, A3 size coated paper, B2 size coated paper, lightweight coated paper, and fine coated paper. It is a coated paper used for printing / publishing printing, and is used for offset printing, gravure printing, and the like.

Specific products include, for example, mirror coat platinum (manufactured by Oji Paper Co., Ltd.), espri coat C (manufactured by Nippon Paper Industries Co., Ltd.) and the like as the cast coated paper.
As the art paper, for example, OK Kanto N, OK Kanto-R40N, SA Kanto N, Satin Kanto N, Satin Kanto-R40N, Ultra Satin Kanto N, Ultra OK Kanto N, Kanon Single Side (all manufactured by Oji Paper Co., Ltd.) NPi Special Art, NPi Super Art, NPi Super Dal, NPi Dal Art (all manufactured by Nippon Paper Industries Co., Ltd.); Utrillo Super Art, Utrillo Super Dal, Utrillo Premium (all manufactured by Daio Paper Co., Ltd.); Fine Art A , Tokuhishi Art, Super Matte Art A, Premium Dal Art A (all manufactured by Mitsubishi Paper Industries Co., Ltd.); Thunderbird Super Art N, Thunderbird Super Art MN, Thunderbird Special Art, Thunderbird Dalart N (all manufactured by Chuetsu Pulp Co., Ltd.) ) And the like.

  As the A2 coated paper, for example, OK top coat + (plus), OK top coat S, OK Casablanca, OK Casablanca V, OK Trinity, OK Trinity NaVi, New Age, New Age W, OK Top Coat Mat N, OK Royal Coat, OK Top Coat Dal, Z Coat, OK Bulk Princess, OK Bulk King, OK Bulk King Satin, OK Top Coat +, OK Non Wrinkle, OK Court V, OK Court N Green 100, OK Matt Court Green 100, New Age Green 100, Z Coat Green 100 (all manufactured by Oji Paper Co., Ltd.); Aurora Coat, Shiraoi Mat, Imperial Mat, Silver Diamond, Recycle Coat 100, Cycle Mat 100 (all manufactured by Nippon Paper Industries Co., Ltd.); Mu Coat, mu Wight, mu mat, white mu mat (all made by Hokuetsu Paper Co., Ltd.); Thunderbird coat N, Regina thunderbird coat 100, Thunderbird mat coat N, Regina thunderbird mat 100 (all made by Chuetsu Pulp Co., Ltd.); Pearl Coat, white pearl coat N, new V mat, white new V mat, pearl coat REW, white pearl coat NREW, new V mat REW, white new V mat REW (all manufactured by Mitsubishi Paper Industries Co., Ltd.).

  As A3 coated (lightweight coated) paper, for example, OK Coat L, Royal Coat L, OK Coat LR, OK White L, OK Royal Coat LR, OK Coat L Green 100, OK Matt Coat L Green 100 (all are Oji Paper Co., Ltd.) Made by Co., Ltd.); Easter DX, Recycle Coat L100, Aurora L, Recycle Mat L100, <SSS> Energy White (both made by Nippon Paper Industries Co., Ltd.); Utrillo Coat L, Mathis Coat (both made by Daio Paper Co., Ltd.) ); High Alpha, Alpha Matt, (N) Kinmari L, Kinmari HiL (Hokuetsu Paper Co., Ltd.); N Pearl Coat L, N Pearl Coat LREW, Swing Mat REW (all manufactured by Mitsubishi Paper Industries); Super Emine, Emine, Chaton (Chuetsu Pulp Industry Co., Ltd. ); And the like.

  Examples of B2 coated (medium-coated) paper include OK medium-coated, (F) MCOP, OK Astro Ross, OK Astrodal, OK Astromat (all manufactured by Oji Paper Co., Ltd.), King O (Nippon Paper Industries Co., Ltd.) Company-made).

  For example, OK Royal Light S Green 100, OK Everlight Coat, OK Everlight R, OK Evergreen, Clean Hit MG, OK Fine Coating Super Eco G, Eco Green Dal, OK Fine Coating Matte Eco G100, OK Starlight Coat, OK Soft Royal, OK Bright, Clean Hit G, Yamayuri Bright, Yamayuri Bright G, OK Aqua Light Coat, OK Royal Light S Green 100, OK Bright (Rough / Glossy), Snow Mat, Snow Mat DX, OK Bulk Princess, OK Bulk Lily (all made by Oji Paper Co., Ltd.); Pyrene DX, Pegasus Hyper 8, Aurora S, Andes DX, Super Andes DX, Space DX, Seine DX, Special Gravure DX, Pegasus, Silver Pegasus, Pegasus -Monony, Greenland DX100, Super Greenland DX100, <SSS> Energy Soft, <SSS> Energy Light, EE Henry (manufactured by Nippon Paper Industries Co., Ltd.); Canto Excel, Excel Super B, Excel Super C, Canto Excel Bal , Heine Excel, Dante Excel (Daiou Paper Co., Ltd.); Cosmo Ace (Daishowa Paperboard Co., Ltd.), Semi-L, High Beta, High Gamma, Shiromari L, Hamming, White Hamming, Semi-Hi Hi, Shiromari HiL (all manufactured by Hokuetsu Paper Industries Co., Ltd.); Ruby Light HREW, Pearl Soft, Ruby Light H (all manufactured by Mitsubishi Paper Industries, Ltd.); Chaton, Ariso, Smash (all manufactured by Chuetsu Pulp & Paper Co., Ltd.) ; Star cherry, Cherry Sue And the like over (Marusumiseishi Co., Ltd.).

  Examples of the special coated paper include some coated paper for electrophotography and coated paper for gravure printing. Specifically, POD gloss coat (manufactured by Oji Paper Co., Ltd.), Space DX (manufactured by Nippon Paper Industries Co., Ltd.), Ace (Nippon Paper Industries Co., Ltd.) and the like can be mentioned. These have an appropriate pore volume of the coating layer and can be used as a recording medium used in the present invention.

[Pretreatment liquid]
The treatment liquid contains at least a surfactant, water, and further contains other components as required.
The pretreatment liquid is not particularly limited as long as it can improve the wettability between the ink and the recording medium, and can be appropriately selected according to the purpose. Since it is based on the technique of promoting aggregation and reacting with ink by containing a cationic compound, it was essential to include a component that reacts with the ink such as a cationic compound, but the pretreatment liquid used in the present invention Does not need to contain such compounds.

  There is no restriction | limiting in particular as said surfactant, According to the objective, it can select suitably, For example, all use of anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant is used. Can do. Among these, nonionic surfactants are particularly preferable because they do not cause unexpected reactions.

Examples of the nonionic surfactant include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acids. Amide ethylene oxide adduct, fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol or sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol And fatty acid amides of alkanolamines. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular as said polyhydric alcohol, According to the objective, it can select suitably, For example, glycerol, a trimethylol propane, a pentaerythritol, sorbitol, sucrose etc. are mentioned. In addition, as the ethylene oxide adduct, a product obtained by substituting a part of ethylene oxide with propylene oxide or alkylene oxide such as butylene oxide is also effective as long as water solubility can be maintained. The substitution rate is preferably 50% or less. 4-15 are preferable and, as for HLB (hydrophilic lipophilic ratio) of the said nonionic activator, 7-13 are more preferable.

  0.05-30 mass% is preferable and, as for content in the said pretreatment liquid of the said surfactant, 1-10 mass% is more preferable.

The pretreatment liquid uses water and a water-soluble organic solvent as main solvents.
The content of the water in the pretreatment liquid is preferably 50 to 99% by mass.

  The water-soluble organic solvent used in the pretreatment liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5 -Polyhydric alcohols such as pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene Polyhydric alcohol alkyl ethers such as recall monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, 1,3-dimethylimidazolidinone and ε-caprolactam; amines such as monoethanolamine, diethanolamine and triethanolamine; sulfur-containing compounds such as sulfolane and thiodiethanol; propylene Examples include carbonate, ethylene carbonate, and γ-butyrolactone. These solvents can be used alone or in combination with water.

  As described above, it is not necessary to add a cationic organic compound to the pretreatment liquid, but it can be used in combination as necessary. Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, (Diallylamine hydrochloride / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate , Polyalkylene polyamine dicyandiamide ammonium salt condensate, dimethyl diallyl ammonium chloride, polydiallyl methylamine hydrochloride, poly (diallyl dimethyl ester) Ruammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine hydrochloride copolymer Products, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. These may be used individually by 1 type and may use 2 or more types together.

  Other components can be added to the pretreatment liquid as necessary, as long as the object and effect of the present invention are not impaired. Examples of the other components include a dispersant, a thickener, a pH adjuster, a preservative, and an antioxidant.

  As a method for applying the pretreatment liquid, methods such as printing the pretreatment liquid using an ink jet nozzle, coating during production of a recording medium, spraying with a spray, etc. can be used. In order to increase the compatibility, it is preferable that an application unit is provided as an image recording apparatus or an auxiliary apparatus so as to contact the recording medium for application.

  Examples of the means for applying the pretreatment liquid in contact with the recording medium include, for example, a roller coating machine, a wire bar, a coating blade, a microgravure, and a means of contacting a foam impregnated with the pretreatment liquid. It is done. Among these, by using a roller, it is possible to apply uniformly with a simple apparatus configuration so that a sufficient image quality improvement effect can be obtained, and the applying means at low cost, And since it becomes possible to produce compactly, it is especially preferable. By applying a small amount to the recording medium by the applying means, the occurrence of cockling of the recording medium can be prevented.

  Here, a method for applying the pretreatment liquid to a recording medium and recording an image with an ink containing a colorant before the pretreatment liquid is dried and solidified will be described with reference to the drawings. The pretreatment liquid applying apparatus and the ink jet recording apparatus in FIG. 19 are apparatuses of a type that records an image by scanning an ink jet recording head.

In the pretreatment applying device and the ink jet recording apparatus of FIG. 19, the recording medium 406 is fed by the paper feed roller 407 and the preprocessing liquid 401 filled in the pretreatment liquid container 442 by the applying roller 404 and the counter roller 405 is the recording medium. Is applied uniformly and thinly. The pretreatment liquid is pumped up by a pumping roller 403 and is uniformly applied to the applying roller 404 by the film thickness control roller 402. The recording medium is fed to a recording scanning unit having the inkjet recording head 420 while being applied with the pretreatment liquid. Since the length of the sheet path from the end portion (A portion in FIG. 19) of the pretreatment liquid application operation to the recording scan start portion (B portion in FIG. 19) is set longer than the length in the feeding direction of the recording medium, recording is performed. When the medium reaches the recording scan start portion, the application of the pretreatment liquid can be completely completed. In this case, the pretreatment liquid can be applied before the inkjet recording head 420 starts scanning for printing and before the recording medium 406 is intermittently conveyed, so that the conveyance speed of the recording medium is constant. It can be applied continuously and can be applied uniformly without unevenness. In the apparatus shown in FIG. 19, the recording medium that requires pre-processing is supplied from the lower cassette, and the recording medium that is not needed to be processed is supplied from the upper cassette. Convenient to provide.
In FIG. 19, 408 is a paper feed tray, 411, 412, 413, 414, 415 and 416 are paper feed rollers, 417 is paper, 418 is a paper feed roller, 420 is a recording head, 421 is an ink cartridge, 422 is A carriage shaft 423 represents a carriage.

<Ink flying process and ink flying means>
The ink flying step is a step of applying a stimulus to ink containing at least a water-dispersible colorant, flying the ink, and recording an image on a pretreated recording medium, and is performed by the ink flying unit. .

〔ink〕
The ink contains at least a water-dispersible colorant, and contains a penetrating agent, a surfactant, a wetting agent, and other components as necessary.

-Maximum ink adhesion (total amount of ink)-
In the present invention, it is preferable to define the total amount of the ink in order to prevent the colorant from penetrating into the ink and efficiently distribute it in the vicinity of the surface of the recording medium and at the same time to ensure the drying property of the ink.
Here, the total amount of ink is an important parameter when forming an image, and means the amount of ink per unit area when a solid image having the highest density is formed. In the present invention, by defining the total amount of ink, it is possible to form a uniform image with less beading and bleeding even on media with poor ink absorption. Conversely, if this amount is exceeded and a large amount of ink is used as in conventional ink jet recording, the separation ability of the pigment as the colorant of the barrier coating layer cannot catch up, and the ink pigment penetrates together with the ink solvent. Insufficient permeation of the solvent component of the ink, and the drying property is greatly hindered, so that a high quality image cannot be obtained.
Specifically, the maximum deposition amount of the ink at the time of image recording (ink total amount regulation value) is preferably 15 g / ^{m 2} or less, more preferably 12 g / ^{m 2} or less, more preferably 5 to 10 g / ^{m 2.} As described above, when the maximum ink adhesion amount is 15 g / m ² or less, a very high-quality image without beading or bleeding can be obtained. This is different from the combination of the conventional dye ink and the ink jet dedicated media. In the case of the pigment ink and the media of the present invention, the color material is present in the form of being deposited on the surface of the media, which is necessary to cover the surface of the media. If there is an amount of color material, not only is the color material more wasted, but even with the highly penetrating ink of the present invention, excess ink solvent interferes with adjacent dots, causing beading and bleeding. It is because it ends up.
In particular, even when the ink used in the present invention is used, if the total amount restriction value of the ink is set high as in the conventional ink jet recording, a large amount of ink is used in the solid portion and the shadow portion, and the color of the media The material separation ability is exceeded, the image is blurred, and the drying property is greatly reduced.
In addition, the total amount of ink used in the ink jet recording method of the present invention is extremely small compared to the conventional ink jet recording method even when image density is required. The lower the color itself, the easier it is for the color material to spread evenly on the media surface. In other words, since the ink spreads thinly on the surface of the media, it can be dried and bleed and beading are difficult to occur even if the ink absorption capability is low.

Further, by reducing the total amount of ink necessary for recording, the capacity of the ink cartridge can be reduced compared to the conventional ink jet printer, and the apparatus can be made compact. Further, if the cartridge size is the same as the conventional one, the replacement frequency of the ink cartridge can be reduced, and the image recording can be performed at a lower cost.
Basically, the smaller the total amount of ink, the better the pigment separation ability of the barrier coating layer. However, if the amount is too small, there is a side effect that the image dot diameter after printing becomes too small. Accordingly, it is preferable to set the total amount of ink within this range.
Here, the maximum adhesion amount of the ink can be measured by a mass method. Specifically, a 5cm x 20cm rectangular solid image is printed at the highest density on Superfine dedicated paper (manufactured by Epson Corporation), which is dedicated to inkjet, and the mass is measured immediately after printing, and the mass before printing is subtracted. The value is multiplied by 100 to obtain the total amount of ink.

-Solid concentration of ink-
The solid content concentration of the ink is preferably 4% by mass or more, and more preferably 5 to 15% by mass. The solid content concentration is less than 4% by mass. The viscosity increase during drying is gradual and the image tends to bleed. On the other hand, if it exceeds 15% by mass, nozzle clogging will increase and the image may be easily lost.

-Water dispersible colorant-
As the colorant, a particulate water-dispersible colorant is used, and it is preferable to use at least one of a pigment and colored fine particles.
As the colored fine particles, an aqueous dispersion of fine polymer particles containing at least one colorant of pigment and dye is preferably used.
Here, the term “containing a color material” means either or both of a state in which the color material is enclosed in the polymer fine particles and a state in which the color material is adsorbed on the surface of the polymer fine particles. The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer, and can be appropriately selected according to the purpose. Here, the “water-insoluble or hardly water-soluble” means that the coloring material does not dissolve 10 parts by mass or more with respect to 100 parts by mass of water at 20 ° C. Further, “dissolve” means that separation or sedimentation of the coloring material is not observed in the surface layer or the lower layer of the aqueous solution visually. The volume average particle diameter of the polymer fine particles (colored fine particles) containing the colorant is preferably 0.01 to 0.16 μm in the ink. If it is 0.01 μm or less, the particle diameter approaches that of the dye, so that light resistance and feathering are deteriorated. Moreover, it becomes easy to osmose | permeate a barrier coating layer, and causes a density | concentration fall. On the other hand, if it is 0.30 μm or more, clogging of the discharge port or clogging with a filter in the printer occurs, and the discharge stability cannot be obtained.

Examples of other colorants include pigments. There is no restriction | limiting in particular as a pigment, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, carbon black, bitumen, and metal powder. Among these, carbon black is preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

Examples of the organic pigment include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable. Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofullerone pigment, an azomethine pigment, and rhodamine B. And lake pigments. Examples of the dye chelates include basic dye chelates and acidic dye chelates.
There is no restriction | limiting in particular as a color of the said pigment, According to the objective, it can select suitably, For example, the thing for black, the thing for color, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the black color include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), oxidation, and the like. Examples thereof include metals such as titanium, organic pigments such as aniline black (CI pigment black 1), and the like.

The carbon black used in the black pigment ink is carbon black produced by a furnace method or a channel method, a primary particle size is 15 to 40 nm, a specific surface area by a BET method is 50 to 300 m ² / g, DBP It is preferable that the oil absorption is 40 to 150 ml / 100 g, the volatile content is 0.5 to 10%, and the pH value is 2 to 9.
Such carbon black is not particularly limited and may be appropriately selected depending on the intended purpose. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, MululL, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot Corporation); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, and 4 (all manufactured by Degussa).

  The color material is not particularly limited for yellow ink, and can be appropriately selected according to the purpose. I. Pigment Yellow 1 (Fast Yellow G), 2, 3, 12 (Disazo Yellow AAA), 13, 14, 16, 17, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 73 74, 75, 81, 83 (Disazo Yellow HR), 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120, 128, 129, 138, 150, 151 , 153, 154, and the like.

  For magenta, there is no particular limitation, and it can be appropriately selected according to the purpose. I. Pigment Red 1, 2, 3, 5, 7, 12, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca )), 48: 3 (permanent red 2B (Sr)), 48: 4 (permanent red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (brilliant carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 92, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 ( Dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 93,202,209,219, and the like.

For cyan, there is no particular limitation, and it can be appropriately selected according to the purpose. I. Pigment Blue 1, 2, 3, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 15:34, 16, 17: 1, 22, 56, 60, 63; C.I. I. Bat Blue 4, 60, etc. are mentioned.
The intermediate color is not particularly limited and may be appropriately selected according to the purpose. For example, for red, green, and blue, C.I. I. Pigment red 177, 194, 224; C.I. I. Pigment orange 43; I. Pigment violet 3, 19, 23, 37; C.I. I. Pigment green 7, 36, and the like.

As the pigment, a self-dispersing pigment that can be stably dispersed without using a dispersant in which at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group is preferably used. It is done. As a result, unlike the conventional ink, a dispersant for dispersing the pigment becomes unnecessary. As the self-dispersing pigment, those having ionicity are preferable, and those having an anionic charge or those having a cationic charge are suitable.
The volume average particle size of the self-dispersing pigment is preferably 0.01 to 0.16 μm in the ink.

Examples of the anionic hydrophilic group, for _{example, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR ( although, M in the formula is hydrogen R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Etc. Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment.
Further, “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium. As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned.

  As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, quaternary ammonium groups listed below are more preferable, and any of these bonded to the pigment surface is suitable as a coloring material. .

The method for producing the cationic self-dispersing carbon black to which the hydrophilic group is bonded is not particularly limited and may be appropriately selected depending on the intended purpose. For example, N-- Examples of the method for bonding the ethylpyridyl group include a method of treating carbon black with 3-amino-N-ethylpyridium bromide.

The hydrophilic group may be bonded to the surface of the carbon black via another atomic group. Examples of other atomic groups include an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Specific examples of the case where the above-described hydrophilic group is bonded to the surface of carbon black via another atomic group include, for example, —C ₂ H ₄ COOM (where M represents an alkali metal or quaternary ammonium). , -PhSO ₃ M (where Ph represents a phenyl group, M represents an alkali metal, quaternary ammonium), -C ₅ H ₁₀ NH ₃ ^{+, and the} like.

A pigment dispersion using a pigment dispersant can also be used for the ink.
As the pigment dispersant, as a hydrophilic polymer compound, in the natural system, vegetable polymers such as gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, alginic acid, Examples include seaweed polymers such as carrageenan and agar; animal polymers such as gelatin, casein, albumin and collagen; microbial polymers such as xanthene gum and dextran. In semi-synthetic systems, cellulose polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and carboxymethylcellulose; starch polymers such as sodium starch glycolate and sodium starch phosphate; sodium alginate and propylene glycol alginate And seaweed polymers such as In pure synthetic systems, vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyvinyl methyl ether; non-crosslinked polyacrylamide, polyacrylic acid or alkali metal salts thereof, acrylic resins such as water-soluble styrene acrylic resins; 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, cationic functional group such as quaternary ammonium and amino group Examples thereof include polymer compounds having a salt in the side chain; natural polymer compounds such as shellac. Among these, those having a carboxyl group introduced from a homopolymer of acrylic acid, methacrylic acid, styrene-acrylic acid or a copolymer of a monomer having another hydrophilic group are particularly preferable as the polymer dispersant.

  The copolymer preferably has a mass average molecular weight of 3,000 to 50,000, more preferably 5,000 to 30,000, and still more preferably 7,000 to 15,000. The mixing mass ratio of the pigment and the dispersant is preferably 1: 0.06 to 1: 3, more preferably 1: 0.125 to 1: 3.

The simultaneous use of the polymer dispersant and the self-dispersing pigment is a preferable combination because an appropriate dot diameter can be obtained. The reason is not clear, but it is thought as follows.
By containing the polymer dispersant, the penetration into the recording paper is suppressed. On the other hand, since the aggregation of the self-dispersing pigment is suppressed by containing the polymer dispersant, the self-dispersing pigment can smoothly spread in the lateral direction. Therefore, it is considered that the dots spread widely and thinly and ideal dots can be formed.

Further, the pigment can be provided with dispersibility by coating with a resin having a hydrophilic group and encapsulating the pigment.
As a method for coating a water-insoluble pigment with an organic polymer and microencapsulating, all conventionally known methods can be used. Conventionally known methods include a chemical production method, a physical production method, a physicochemical production method, and a mechanical production method. Specifically, the following methods are mentioned.

(1) Interfacial polymerization method (a method in which two kinds of monomers or two kinds of reactants are dissolved separately in a dispersed phase and a continuous phase, and both substances are reacted at the interface between them to form a wall film)
(2) In-situ polymerization method (liquid or gas monomer and catalyst, or two types of reactive substances are supplied from either one of the continuous phase core particles to cause a reaction to form a wall film)
(3) Liquid-cured coating method (method of forming a wall film by insolubilizing droplets of a polymer solution containing core material particles in a liquid with a curing agent)
(4) Coacervation (phase separation) method (a method in which a polymer dispersion in which core material particles are dispersed is separated into a coacervate (concentrated phase) having a high polymer concentration and a dilute phase to form a wall membrane)
(5) In-liquid drying method (preparing a liquid in which a core substance is dispersed in a solution of a wall membrane material, placing the dispersion in a liquid in which the continuous phase of this dispersion is not miscible to form a composite emulsion, Method of forming a wall film by gradually removing the dissolved medium)
(6) Melt-dispersed cooling method (using a wall film material that melts into a liquid state and solidifies at room temperature when heated, this material is heated and liquefied, core material particles are dispersed therein, and it is cooled into fine particles. A method of forming a wall film)
(7) Air suspension coating method (powder core material particles are suspended in the air by a fluidized bed, and the wall membrane material coating solution is sprayed and mixed while suspended in the air stream to form a wall membrane. Method)
(8) Spray drying method (method of spraying the encapsulated stock solution and bringing it into contact with hot air to evaporate and dry the volatile matter to form a wall film)
(9) Acid precipitation method (by neutralizing at least a part of the anionic group of the organic polymer compound containing an anionic group with a basic compound to provide solubility in water in an aqueous medium together with a coloring material) After kneading, make neutral or acidic with an acidic compound, deposit organic compounds and fix them on the colorant, and then neutralize and disperse)
(10) Phase inversion emulsification method (a mixture containing an anionic organic polymer having dispersibility in water and a colorant is used as an organic solvent phase, and water is added to the organic solvent phase or water The method of charging the organic solvent phase into

Examples of organic polymers (resins) used as the material constituting the microcapsule wall membrane material include polyamide, polyurethane, polyester, polyurea, epoxy resin, polycarbonate, urea resin, melamine resin, phenol resin, and polysaccharide. , Gelatin, gum arabic, dextran, casein, protein, natural rubber, carboxypolymethylene, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, cellulose, ethyl cellulose, methyl cellulose, nitrocellulose, hydroxyethyl cellulose, acetic acid Cellulose, polyethylene, polystyrene, (meth) acrylic acid polymer or copolymer, (meth) acrylic acid ester polymer or copolymer, (meth) acrylic acid- (me ) Acrylic acid ester copolymer, styrene - (meth) acrylic acid copolymer, styrene - maleic acid copolymer, sodium alginate, fatty acids, paraffin, beeswax, water wax, hardened beef tallow, carnauba wax, and albumin.
Among these, organic polymers having an anionic group such as a carboxylic acid group or a sulfonic acid group can be used. Nonionic organic polymers include, for example, polyvinyl alcohol, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate or their (co) polymers, and 2-oxazoline cationic ring-opening polymers. Is mentioned. In particular, a completely saponified product of polyvinyl alcohol is particularly preferable because it has low water solubility and is easily dissolved in hot water but difficult to dissolve in cold water.

  Further, the amount of the organic polymer constituting the wall membrane material of the microcapsule is preferably 1 to 20% by mass with respect to a water-insoluble colorant such as an organic pigment or carbon black. By setting the amount of the organic polymer within the above range, the content of the organic polymer in the capsule is relatively low, so that the color development of the pigment is caused by the organic polymer covering the pigment surface. It becomes possible to suppress the fall of property. If the amount of the organic polymer is less than 1% by mass, it may be difficult to exert the effect of encapsulation, and if it exceeds 20% by mass, the color developability of the pigment may be significantly reduced. In consideration of other characteristics, the amount of the organic polymer is preferably in the range of 5 to 10% by mass relative to the water-insoluble colorant. That is, since a part of the color material is exposed without being substantially covered, it is possible to suppress a decrease in color developability, and conversely, a part of the color material is not exposed and is substantially not exposed. Since it is coated, it is possible to simultaneously exhibit the effect that the pigment is coated. Further, the number average molecular weight of the organic polymers used in the present invention is preferably 2,000 or more from the viewpoint of capsule production. Here, “substantially exposed” means not the partial exposure associated with defects such as pinholes and cracks, but a state where it is intentionally exposed.

Furthermore, if an organic pigment or self-dispersing carbon black, which is a self-dispersing pigment, is used as a colorant, the dispersibility of the pigment is improved even when the content of the organic polymer in the capsule is relatively low. Furthermore, it is more preferable because sufficient storage stability of the ink can be ensured.
It is preferable to select an organic polymer suitable for the microencapsulation method. For example, in the case of interfacial polymerization, polyester, polyamide, polyurethane, polyvinyl pyrrolidone, epoxy resin and the like are suitable. In the case of in-situ polymerization method, a polymer or copolymer of (meth) acrylic acid ester, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer Polyvinyl chloride, polyvinylidene chloride, polyamide and the like are suitable. In the case of the in-liquid curing method, sodium alginate, polyvinyl alcohol, gelatin, albumin, epoxy resin and the like are suitable. In the case of the coacervation method, gelatin, celluloses, casein and the like are suitable. Moreover, in order to obtain a fine and uniform microencapsulated pigment, it is possible to use all conventionally known encapsulation methods other than the above.
When the phase inversion method or the acid precipitation method is selected as the microencapsulation method, anionic organic polymers are used as the organic polymers constituting the wall membrane material of the microcapsules. The phase inversion method is a composite or composite of an anionic organic polymer having self-dispersibility or solubility in water and a colorant such as a self-dispersion organic pigment or self-dispersion carbon black, or a self-dispersion method. A mixture of a colorant such as a dispersible organic pigment or self-dispersing carbon black, a curing agent, and an anionic organic polymer is used as an organic solvent phase, and water is added to the organic solvent phase or the organic solvent is submerged in water. In this method, a solvent phase is introduced and microencapsulation is performed while self-dispersion (phase inversion emulsification) is performed. In the above phase inversion method, there is no problem even if an ink vehicle and additives are mixed in the organic solvent phase. In particular, it is more preferable to mix an ink liquid medium because a dispersion liquid for ink can be directly produced.

On the other hand, in the acid precipitation method, a part or all of the anionic group of the anionic group-containing organic polymer is neutralized with a basic compound, a colorant such as a self-dispersing organic pigment or self-dispersing carbon black, A water-containing cake obtained by a production method comprising a step of kneading in an aqueous medium and a step of neutralizing and acidifying an acidic compound to precipitate an anionic group-containing organic polymer and fixing the pigment to a pigment, This is a method of microencapsulation by neutralizing part or all of an anionic group using a compound. By doing in this way, the aqueous dispersion containing the anionic microencapsulated pigment which is fine and contains many pigments can be manufactured.
Examples of the solvent used for microencapsulation as described above include alkyl alcohols such as methanol, ethanol, propanol and butanol; aromatic hydrocarbons such as benzol, toluol and xylol; methyl acetate Esters such as ethyl acetate and butyl acetate; Chlorinated hydrocarbons such as chloroform and ethylene dichloride; Ketones such as acetone and methyl isobutyl ketone; Ethers such as tetrahydrofuran and dioxane; Cellosolves such as methyl cellosolve and butyl cellosolve Etc. The microcapsules prepared by the above method are once separated from these solvents by centrifugation or filtration, and are stirred and redispersed together with water and necessary solvents to obtain the desired ink. The average particle diameter of the encapsulated pigment obtained by the above method is preferably 50 to 180 nm.
By coating the resin in this manner, the pigment adheres firmly to the recording medium, so that the scratching property of the ink recorded matter can be improved.

  The amount of the colorant added to the ink is preferably 6 to 15% by mass, and more preferably 8 to 12% by mass. When the addition amount is less than 6% by mass, the image density may be lowered due to a decrease in coloring power, or feathering or bleeding may be deteriorated due to a decrease in viscosity. If left unattended, the nozzles will easily dry, causing non-ejection phenomenon, the viscosity becomes too high, penetrability will decrease, and the dots will not spread, so the image density will decrease. , The image may become blurred.

-Penetration agent-
As the penetrant, a polyol compound having 8 or more carbon atoms and a glycol ether compound are used.
If the polyol compound has less than 8 carbon atoms, sufficient penetrability cannot be obtained, and the recording medium is soiled during double-sided printing, or the ink spreading on the recording medium is insufficient, resulting in poor pixel filling. In some cases, character quality and image density may decrease.

Suitable examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  The addition amount of the penetrant in the ink is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass.

-Wetting agent-
There is no restriction | limiting in particular as said wetting agent, According to the objective, it can select suitably, For example, at least 1 sort (s) selected from a polyol compound, a lactam compound, a urea compound, and saccharides is suitable.

Examples of the polyol compound include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,3-purpandiol, 1,3-butanediol, 1,4-butanediol, and 3-methyl-1. , 3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petri Polyhydric alcohols such as all; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene group Glycol monomethyl ether, polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether, ethylene glycol monophenyl ether, and polyhydric alcohol aryl ethers such as ethylene glycol monobenzyl ether. These may be used alone or in combination of two or more.
Among these, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene are obtained because they have excellent effects on solubility and prevention of poor jetting properties due to water evaporation. Glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,6-hexane Diol, 2-methyl-2,4-pentanediol, 1,2,4-butanetriol, 1,2,6-hexanetriol, thiodiglycol, pentaerythritol, trimethylolethane, and trimethylolpropane are preferred.

Examples of the lactam compound include at least one selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, and ε-caprolactam.
Examples of the urea compound include at least one selected from urea, thiourea, ethylene urea, and 1,3-dimethyl-2-imidazolidinone. In general, the amount of urea added to the ink is preferably 0.5 to 50% by mass, and more preferably 1 to 20% by mass.

  Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and derivatives thereof. Among these, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose are preferable, and maltose, sorbitol, gluconolactone, and maltose are particularly preferable.

The polysaccharide means a saccharide in a broad sense and can be used to include substances widely existing in nature such as α-cyclodextrin and cellulose.
The derivative of the saccharide is represented by a reducing sugar of the saccharide (for example, sugar alcohol (wherein general formula: HOCH ₂ (CHOH) _n CH ₂ OH (where n represents an integer of 2 to 5)). , Oxidized sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Among these, sugar alcohols are particularly preferable, and examples of the alcohol include maltitol, sorbit, and the like.

  The content of the wetting agent in the ink is preferably 10 to 50% by mass, and more preferably 15 to 35% by mass. If the content is too small, the nozzle is likely to be dried and defective ejection of droplets may occur. If the content is too large, the ink viscosity is increased, and the proper viscosity range may be exceeded.

-Surfactant-
The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, a nonionic surfactant, an acetylene glycol type And surfactants, fluorine surfactants, and the like, and in particular, at least one selected from the following general formulas (I), (II), (III), (IV), (V), and (VI) Species are preferred.

R ¹ —O— (CH ₂ CH ₂ O) _h CH ₂ COOM —General Formula (I)
In the general formula (I), ^{R 1} represents an alkyl group. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

In the general formula (II), R ² represents an alkyl group, examples thereof include an alkyl group branched carbon atoms and optionally 1 to 14. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

In the general formula (III), R ³ is represents a hydrocarbon group, for example, such as an alkyl group branched carbon atoms and optionally 1 to 14. k represents an integer of 5 to 20.
_{^{R 4 - (OCH 2 CH 2}} ) j OH ··· formula (IV)
In the general formula (IV), R ⁴ represents a hydrocarbon group, for example, such as an alkyl group branched carbon atoms and optionally 1 to 14. j represents an integer of 5 to 20.

In the general formula (V), R ⁶ represents a hydrocarbon group, for example, such as an alkyl group branched carbon atoms and optionally 1 to 14. L and p each represent an integer of 1 to 20.

However, in said general formula (VI), q and r represent the integer of 0-40, respectively.

Hereinafter, the surfactants of the general formulas (I) and (II) are specifically shown in free acid form.
(I-1): CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₃ CH ₂ COOH
_{(I-2): CH 3} (CH 2) 12 O (CH 2 CH 2 O) 4 CH 2 COOH
(I-3): CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₅ CH ₂ COOH
(I-4): CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₆ CH ₂ COOH

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecyl benzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, and polyoxyethylene. Examples thereof include alkylamine and polyoxyethylene alkylamide.

  Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. Specific examples include lauryl dimethylamine oxide, myristyl dimethylamine oxide, stearyl dimethylamine oxide, dihydroxyethyl lauryl amine oxide, polyoxyethylene coconut oil alkyl dimethyl amine oxide, dimethyl alkyl (coconut) betaine, dimethyl lauryl betaine, and the like. It is done.

  Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, , 5-dimethyl-1-hexyn-3-ol and the like (for example, Surfynol 104, 82, 465, 485 or TG manufactured by Air Products (USA)) can be used. Of these, Surfynol 465, 104 and TG in particular exhibit good print quality.

As the fluorosurfactant, those represented by the following general formula (i) are suitable.
<General formula (i)>
CF ₃ CF ₂ (CF ₂ CF ₂ ) _m —CH ₂ CH ₂ O (CH ₂ CH ₂ O) _n H
However, in said general formula (i), m represents the integer of 0-10. n represents an integer of 1 to 40.

Examples of the fluorosurfactant include perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, and perfluoroalkylamine oxide. Compound etc. are mentioned.
Examples of the fluorosurfactant include those commercially available, such as Surflon S-111, S-112, S-113, S121, S131, S132, S-141, and S-145 (all are Asahi Glass. Made by Sumitomo 3M Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431, FC-4430 ); Megafuck F-470, F-1405, F474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl FS-300, FSN, FSN-100, FSO (all manufactured by DuPont); EF-351, 352, 801, 802 (all of which are manufactured by Gemco), and the like. Among these, Zonyl FS-300, FSN, FSN-100, and FSO (all manufactured by DuPont) which are favorable in terms of reliability and color development can be suitably used.

-Ink fixing agent-
The ink fixing agent is to maintain the adhesion between the colorant, the surface of the recording medium, and the colorant at a certain level. Without the fixing agent, the colorant pigment is easily peeled off after printing. A fixing agent should be used if stability is required. The fixing agent may be a low molecular weight one, but a resin emulsion or an ultraviolet curable resin is preferable.

The resin emulsion is obtained by dispersing resin fine particles in water as a continuous phase, and may contain a dispersant such as a surfactant as necessary.
The content of the resin fine particles (content of resin fine particles in the resin emulsion) is generally preferably 10 to 70% by mass. Further, the particle diameter of the resin fine particles is preferably 10 to 1,000 nm, more preferably 20 to 300 nm, considering use in an ink jet recording apparatus.

  The resin fine particles are not particularly limited and may be appropriately selected depending on the purpose. For example, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride Examples include resins, acrylic-styrene copolymer resins, acrylic-silicone copolymer resins, and among these, acrylic-silicone copolymer resins are particularly preferable.

As the resin fine particles, those appropriately synthesized may be used, or commercially available products may be used.
Examples of the commercially available resin emulsion include microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.); Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.). Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.); SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.); Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.); Primal AC-22, AC-61 (acrylic resin emulsion, manufactured by Rohm and Haas); Nanoacryl SBCX-2821, 3689 (acrylic silicone resin emulsion, Toyo Ink Co., Ltd.) Ltd. Formula Company); # 3070 (methyl methacrylate polymer resin emulsion, manufactured by Mikuni Color Ltd.).

  The addition amount of the resin fine particle component in the resin emulsion in the ink is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass, and still more preferably 1 to 10% by mass. When the addition amount is less than 0.1% by mass, the effect of improving clogging resistance and ejection stability may not be sufficient, and when it exceeds 50% by mass, the storage stability of the ink may be reduced. .

Examples of the ultraviolet curable resin include those obtained by polymerizing at least one of an acrylic photopolymerizable monomer and an acrylic photopolymerizable oligomer.
The photopolymerizable monomer is preferably an unsaturated carboxylic acid such as (meth) acrylic acid or an ester thereof, such as alkyl- (meth) acrylate, cycloalkyl- (meth) acrylate, or halogenated alkyl- (meth). ) Acrylate, alkoxyalkyl- (meth) acrylate, hydroxyalkyl- (meth) acrylate, aminoalkyl- (meth) acrylate, tetrahydrofurfuryl- (meth) acrylate, allyl- (meth) acrylate, glycidyl- (meth) acrylate, Benzyl- (meth) acrylate, phenoxy- (meth) acrylate; alkylene glycol, polyoxyalkylene glycol mono- or di- (meth) acrylate, trimethylolpropane tri- (meth) acrylate, pentaerythritol tetra- (meth) acrylate Relates and so on.
Further, acrylamide, methacrylamide or derivatives thereof, for example, (meth) acrylamide, diacetone (meth) acrylamide, N, N′-alkylenebis (meth) acrylamide, which are mono-substituted or di-substituted with an alkyl group or a hydroxyalkyl group, may be mentioned. It is done.
Also, allyl compounds such as allyl alcohol, allyl isocyanate, diallyl phthalate, triallyl isocyanurate and the like can be mentioned.
Moreover, isobornyl (meth) acrylate, norbornyl (meth) acrylate, dicyclopentenoxyethyl (meth) acrylate, dicyclopentenoxypropyl (meth) acrylate, etc. are mentioned.
Moreover, the (meth) acrylic acid ester of diethylene glycol dicyclopentenyl monoether, the (meth) acrylic acid ester of polyoxyethylene or polypropylene glycol dicyclopentenyl monoether, etc. are mentioned.
In addition, 3,9-bis (1,1-bismethyl-2-oxyethyl) -spiro [5] such as dicyclopentenyl cinnamate, dicyclopentenoxyethyl cinnamate, dicyclopentenoxyethyl monofumarate or difumarate , 5] undecane, 3,9-bis (1,1-bismethyl-2-oxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2-oxyethyl) -Mono-, diacrylate or mono-, dimeta such as spiro [5,5] undecane, 3,9-bis (2-oxyethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Acrylate, or mono-, diacrylate, or mono- of these spiroglycol ethylene oxide or propylene oxide addition polymers, Methacrylate, methyl ether of the above monoacrylate or methacrylate, 1-azabicyclo [2,2,2] -3-octenyl acrylate or methacrylate, bicyclo [2,2,1] -5-heptene-2,3-di Examples include carboxyl monoallyl ester, dicyclopentadienyl acrylate or methacrylate, dicyclopentadienyloxyethyl acrylate or methacrylate, dihydrodicyclopentadienyl acrylate or methacrylate. These may be used singly or in combination of two or more.

  Examples of the acrylic photopolymerizable oligomer include epoxy resin acrylic ester, unsaturated polyester prepolymer, polyvinyl alcohol prepolymer, polyacrylic acid or maleic acid copolymer prepolymer, urethane prepolymer, and the like. .

Examples of the acrylic ester of the epoxy resin include diglycidyl ether diacrylate of bisphenol A, a reaction product of an epoxy resin, acrylic acid and methyltetrahydrophthalic anhydride, and a reaction of the epoxy resin and 2-hydroxyethyl acrylate. Products, ring-opening copolymers of glycidyl diacrylate and phthalic anhydride, and the like.
Examples of the unsaturated polyester-based prepolymer include esters of methacrylic acid dimer and polyol, polyesters obtained from acrylic acid, phthalic anhydride and propylene oxide, reaction products of polyvinyl alcohol and N-methylolacrylamide, polyethylene Examples include a reaction product of glycol, maleic anhydride, and glycidyl methacrylate.
Examples of the polyvinyl alcohol-based prepolymer include those obtained by esterifying polyvinyl alcohol with succinic anhydride and then adding glycidyl methacrylate.
Examples of the polyacrylic acid or maleic acid copolymer prepolymer include a reaction product of methyl vinyl ether-maleic anhydride copolymer and 2-hydroxyethyl acrylate, or a product obtained by further reacting this with glycidyl methacrylate. It is done.
Examples of the urethane prepolymer include those having a polyoxyalkylene segment and / or a saturated polyester segment linked via a urethane bond, and having an acryloyl group or a methacryloyl group at both ends.

-Other ingredients-
The other components are not particularly limited and can be appropriately selected as necessary. For example, pH adjusters, antiseptic / antifungal agents, rust preventives, antioxidants, ultraviolet absorbers, oxygen absorbers, And light stabilizers.

  Examples of the antiseptic / antifungal agent include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, and sodium pentachlorophenol. Can be mentioned.

  The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared, and any substance can be used according to the purpose. Examples of the pH adjuster include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide, quaternary ammonium hydroxide, Examples thereof include quaternary phosphonium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

Examples of the antioxidant include phenol-based antioxidants (including hindered phenol-based antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
Examples of the phenolic antioxidants (including hindered phenolic antioxidants) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-Butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy] ethyl] 2,4,8,10-tetrixaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4- Hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, and the like.

Examples of the amine-based antioxidant include phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N′-diphenyl-p-phenylenediamine. 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene -3 (3,5-di-tert-butyl-4-dihydroxyphenyl) propionate] methane, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, and the like.
Examples of the sulfur-based antioxidant include dilauryl 3,3′-thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl β. , β′-thiodipropionate, 2-mercaptobenzimidazole, dilauryl sulfide and the like.
Examples of the phosphorus antioxidant include triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite, trilauryl trithiophosphite, trinonylphenyl phosphite, and the like.

Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.
Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.
Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like.
Examples of the salicylate-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.
Examples of the cyanoacrylate-based ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2- And cyano-3-methyl-3- (p-methoxyphenyl) acrylate.
Examples of the nickel complex-based ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), and 2,2′-thiobis. (4-tert-octyl ferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octyl ferrate) triethanolamine nickel (II), and the like.

  The ink used in the ink jet recording method of the present invention is further necessary by dispersing or dissolving at least water, a colorant, a water-soluble organic solvent, a wetting agent, a surfactant, and, if necessary, other components in an aqueous medium. According to the above, the mixture is mixed by stirring. The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

As physical properties of the ink, for example, the viscosity, surface tension, pH, and the like are preferably in the following ranges.
The viscosity is preferably 3 mPa · s or more at 25 ° C., more preferably 5 to 20 mPa · s. If the viscosity exceeds 20 mPa · s, it may be difficult to ensure ejection stability.
The surface tension is preferably 25 mN / m or less, more preferably 20 mN / m or less at 25 ° C. When the surface tension exceeds 25 mN / m, ink penetration is slow and a phenomenon that the image is blurred occurs, so that a high-quality image may not be obtained. The lower the surface tension is, the better the separation between the pigment and the solvent is improved, but 14 mN / m or more is preferable. The surface tension of the ink can be easily adjusted by the amount of penetrating agent added and the amount of surfactant (particularly fluorosurfactant) added.
As said pH, 7-10 are preferable, for example.

  There is no restriction | limiting in particular as coloring of the said ink, According to the objective, it can select suitably, Yellow, magenta, cyan, black etc. are mentioned. When recording is performed using an ink set in which two or more of these colorings are used in combination, a multicolor image can be formed. When recording is performed using an ink set in which all colors are combined, a full color image is formed. be able to.

  The ink is an ink jet head that uses a piezoelectric element as pressure generating means for pressurizing the ink in the ink flow path, deforms a diaphragm that forms the wall surface of the ink flow path, and changes the volume of the ink flow path to change the ink flow volume. A so-called piezo-type device that ejects droplets (see JP-A-2-51734) or a so-called thermal-type device that generates bubbles by heating ink in an ink flow path using a heating resistor (JP-A-2-51734) No. 61-59911), the diaphragm and the electrode forming the wall surface of the ink flow path are arranged opposite to each other, and the diaphragm is deformed by the electrostatic force generated between the diaphragm and the electrode, thereby allowing the ink flow. Good for printers equipped with any inkjet head such as an electrostatic type (see Japanese Patent Laid-Open No. 6-71882) that discharges ink droplets by changing the volume in the path It can be used for.

  As described above, the combination of the recording medium and ink used in the present invention can be suitably used in various fields, and can be suitably used in an image recording apparatus (printer or the like) using an inkjet recording method. For example, it can be particularly suitably used in the following ink cartridges, ink recordings, ink jet recording apparatuses, and ink jet recording methods.

<Ink cartridge>
The ink cartridge used in the present invention contains the ink in the ink jet recording method of the present invention in a container, and further includes other members and the like appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.

Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 is a view showing an example of the ink cartridge of the present invention, and FIG. 2 is a view including a case (exterior) of the ink cartridge 200 of FIG.
As shown in FIG. 1, the ink cartridge 200 is filled into the ink bag 241 from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port 243 made of a rubber member and supplied to the apparatus.
The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably attached to various ink jet recording apparatuses.

  The ink cartridge contains ink in the ink jet recording method of the present invention and can be used by being detachably attached to various ink jet recording apparatuses, and can be detachably attached to the ink jet recording apparatus of the present invention described later. It is particularly preferable to use it.

The ink flying means is means for applying an stimulus to the ink in the ink jet recording method of the present invention and causing the ink to fly to record an image on the recording medium. The ink flying means is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include various nozzles for ejecting ink.
In the present invention, it is preferable that at least a part of the liquid chamber portion, the fluid resistance portion, the vibration plate, and the nozzle member of the ink jet head is formed of a material containing at least one of silicon and nickel.
The nozzle diameter of the inkjet nozzle is preferably 30 μm or less, and preferably 1 to 20 μm.
In addition, it is preferable that a sub tank for supplying ink is provided on the ink jet head, and the sub tank is replenished with ink from an ink cartridge through a supply tube.
In the ink jet recording method of the present invention, it is preferable to use any one of ink having a droplet size of 20 pl or more and a combination of ink having a droplet size of 20 pl or more and ink having a droplet size of less than 20 pl.

  The stimulus can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, and includes heat, pressure, vibration, light, and the like. . These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.

  Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, Examples include thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, electrostatic actuators that use electrostatic force, etc. It is done.

  There is no particular limitation on the mode of ink flying in the ink media set, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, a recording signal is output to the ink in the recording head. A method of applying corresponding thermal energy using, for example, a thermal head, generating bubbles in the ink by the thermal energy, and discharging and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles , Etc. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head.

  The ejection speed of the ejected ink is preferably 5 to 20 m / s, the driving frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

One mode for carrying out the ink jet recording method of the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings. The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper loaded on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104. In FIG. 3, reference numeral 111 denotes an upper cover, and 112 denotes a front surface.
On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 201.

  In the apparatus main body 101, as shown in FIGS. 4 and 5, the carriage 133 is slid in the main scanning direction by guide rods 131 and stays 132 which are horizontally mounted on left and right side plates (not shown). It is held movably and moved and scanned in the direction of the arrow in FIG. 5 by a main scanning motor (not shown).

The carriage 133 is provided with a recording head 134 composed of four ink jet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.
As the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used.
In addition, the carriage 133 is equipped with a sub tank 135 for each color for supplying ink of each color to the recording head 134. The sub tank 135 is supplied with ink from the ink cartridge 201 loaded in the ink cartridge loading unit 105 via an ink supply tube (not shown) and is replenished.

  On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A separation pad 144 made of a material having a large coefficient of friction is provided facing the paper roller 143) and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.

  As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° so as to follow the transport belt 151. A conveying guide 153 and a tip pressure roller 155 urged toward the conveying belt 151 by a pressing member 154, and a charging roller 156 as a charging means for charging the surface of the conveying belt 151. It has been.

  The conveyance belt 151 is an endless belt, is stretched between the conveyance roller 157 and the tension roller 158, and can circulate in the belt conveyance direction. The transport belt 151 includes, for example, a surface layer serving as a sheet adsorption surface formed of a resin material having a thickness of about 40 μm that is not subjected to resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the same surface layer. It has a back layer (medium resistance layer, earth layer) that has been subjected to resistance control with carbon as a material. On the back side of the conveyance belt 151, a guide member 161 is arranged corresponding to a printing area by the recording head 134. Note that, as a paper discharge unit for discharging the paper 142 recorded by the recording head 134, a separation claw 171 for separating the paper 142 from the conveyance belt 151, a paper discharge roller 172, and a paper discharge roller 173 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 172.

  A double-sided paper feeding unit 181 is detachably mounted on the back surface of the apparatus main body 101. The double-sided paper feeding unit 181 takes in the paper 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds it again between the counter roller 152 and the transport belt 151. A manual paper feed unit 182 is provided on the upper surface of the duplex paper feed unit 181.

In this ink jet recording apparatus, the paper 142 is separated and fed one by one from the paper feed unit, and the paper 142 fed substantially vertically upward is guided by the guide 145 and between the transport belt 151 and the counter roller 152. It is sandwiched and conveyed. Further, the leading end is guided by the conveying guide 153 and pressed against the conveying belt 151 by the leading end pressure roller 155, and the conveying direction is changed by approximately 90 °.
At this time, the conveying belt 151 is charged by the charging roller 156, and the sheet 142 is electrostatically attracted to the conveying belt 151 and conveyed. Therefore, by driving the recording head 134 according to the image signal while moving the carriage 133, ink droplets are ejected onto the stopped paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103.
When a near-end remaining amount of ink in the sub tank 135 is detected, a required amount of ink is supplied from the ink cartridge 201 to the sub tank 135.

  In this ink jet recording apparatus, when the ink in the ink cartridge 201 is used up, the casing of the ink cartridge 201 can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge 201 can supply ink stably even when the ink cartridge 201 is placed vertically and has a front loading configuration. Therefore, when the upper portion of the apparatus main body 101 is closed and installed, for example, even when the apparatus main body 101 is stored in a rack or an object is placed on the upper surface of the apparatus main body 101, the ink cartridge 201 is replaced. Can be easily performed.

  Here, an example is described in which the present invention is applied to a serial (shuttle type) ink jet recording apparatus that is scanned by a carriage, but the present invention can be similarly applied to a line type ink jet recording apparatus having a line type head.

  Further, the ink jet recording apparatus and the ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method. For example, the ink jet recording apparatus, the facsimile apparatus, the copying apparatus, the printer / fax / copier multifunction machine, etc. It can be particularly preferably applied.

Hereinafter, an ink jet head to which the present invention is applied will be described.
FIG. 6 is an enlarged view of elements of an ink jet head according to an embodiment of the present invention, and FIG. 7 is an enlarged cross-sectional view of the main part in the channel-to-channel direction of the head.
This ink jet head includes a frame 10 formed with an engraving serving as an ink supply port (not shown) and a common liquid chamber 1b, and a communication port 2c communicating with the fluid resistance portion 2a and the engraving serving as the pressurized liquid chamber 2b and the nozzle 3a. The formed flow path plate 20, the nozzle plate forming the nozzle 3 a, the vibration plate 60 having the convex portion 6 a, the diaphragm portion 6 b, and the ink inlet 6 c, and the vibration plate 60 bonded to each other through the adhesive layer 70. A laminated piezoelectric element 50 and a base 40 to which the laminated piezoelectric element 50 is fixed are provided.
The base 40 is made of a barium titanate ceramic, and the laminated piezoelectric elements 50 are arranged in two rows and joined.
The laminated piezoelectric element 50 is formed by alternately laminating a lead zirconate titanate (PZT) piezoelectric layer having a thickness of 10 to 50 μm / layer and an internal electrode layer made of silver / palladium (AgPd) having a thickness of several μm / layer. is doing. The internal electrode layer is connected to the external electrode at both ends.
The laminated piezoelectric element 50 is divided on comb teeth by half-cut dicing, and is used as a drive unit 5f and a support unit 5g (non-drive unit) one by one. The length of the outside of the external electrode is limited by cutting or the like so as to be divided by half-cut dicing, and these become a plurality of individual electrodes. The other is not divided by dicing but is conductive and becomes a common electrode.
The FPC 8 is soldered to the individual electrodes of the drive unit. In addition, the common electrode is provided with an electrode layer at the end of the laminated piezoelectric element, and is wound around and joined to the Gnd electrode of the FPC 8. A driver IC (not shown) is mounted on the FPC 8 to control application of a driving voltage to the driving unit 5f.

The diaphragm 60 is joined to a thin film diaphragm portion 6b, an island-shaped convex portion (island portion) 6a that joins the laminated piezoelectric element 50 that is the driving portion 5f formed at the center portion of the diaphragm portion 6b, and a support portion. A thick film portion including a beam and an opening serving as an ink inflow port 6c are formed by stacking two layers of Ni plating films by electroforming. The diaphragm portion has a thickness of 3 μm and a width of 35 μm (one side).
The island-shaped convex part 6a of the diaphragm 60 and the movable part 5f of the laminated piezoelectric element 50, and the coupling of the diaphragm 60 and the frame 10 are bonded by patterning the adhesive layer 70 including a gap material.

The flow path plate 20 uses a silicon single crystal substrate, and the engraving that becomes the fluid resistance portion 2a and the pressurized liquid chamber 2b and the through-hole that becomes the communication port 2c at the position with respect to the nozzle 3a are patterned by an etching method.
The portion left by etching becomes the partition wall 2d of the pressurized liquid chamber 2b. Further, in this head, a portion for narrowing the etching width is provided and this is used as the fluid resistance portion 2a.
The nozzle plate 30 is formed of a metal material, for example, an Ni plating film formed by an electroforming method, and has a number of nozzles 3a that are fine discharge ports for causing ink droplets to fly. The inner shape (inner shape) of the nozzle 3a is formed in a horn shape (may be a substantially cylindrical shape or a substantially frustum shape). The diameter of the nozzle 3a is 20 to 35 [mu] m on the ink droplet outlet side. The nozzle pitch in each row was 150 dpi.

The frame 10 that forms the engraving that becomes the ink supply port and the common liquid chamber 1b is made by resin molding.
In the ink jet head configured as described above, a driving waveform (pulse voltage of 10 to 50 V) is applied to the driving unit 5f in accordance with the recording signal, thereby causing displacement in the stacking direction in the driving unit 5f, and the diaphragm 30. The pressurized liquid chamber 2b is pressurized through the pressure to increase the pressure, and ink droplets are ejected from the nozzle 3a.
Thereafter, the ink pressure in the pressurizing liquid chamber 2b is reduced with the end of ink droplet ejection, and negative pressure is generated in the pressurizing liquid chamber 2b due to the inertia of the ink flow and the discharge process of the drive pulse, and the ink is filled. Move to the process. At this time, the ink supplied from the ink tank flows into the common liquid chamber 1b, passes from the common liquid chamber 1b through the ink inlet 6c, passes through the fluid resistance portion 2a, and is filled into the pressurized liquid chamber 2b.
The fluid resistance portion 2a is effective in damping the residual pressure vibration after ejection, but becomes resistant to refilling (refilling) due to surface tension. By appropriately selecting the fluid resistance portion, it is possible to balance the attenuation of the residual pressure and the refill time, and to shorten the time (drive cycle) until the transition to the next ink droplet ejection operation.

The nozzle surface of the ink jet head used in the present invention may be coated with a material having water repellency. By being coated in this way, the liquid causing the dirt is repelled and the liquid is prevented from adhering to the nozzle surface. For this reason, it is possible to prevent the orifice and the discharge port from being blocked by the particles generated by the solidification of the dirt. Even if it adheres, its binding force is weak.
In addition, when the surface tension of the ink is low, the ink spreads to the vicinity of the nozzle on a general nozzle surface, and a normal meniscus may not be formed. In such a state, ink ejection bends or non-ejection occurs. However, if the nozzle surface is coated with a water-repellent material, the ink does not spread in the vicinity of the nozzle and remains in the nozzle, so that normal ejection can be performed.

The water repellent film may be formed by vapor deposition under vacuum or may be applied after being dissolved in a suitable solvent. As the vacuum deposition, for example, the inside of the vacuum chamber is evacuated to a predetermined degree of vacuum with a vacuum pump, and then the water-repellent material is vaporized at 400 ° C. and introduced into the vacuum chamber to adjust the vacuum atmosphere, The water repellent film can be formed on the orifice surface by supplying power from the power source to the discharge electrode to cause RF glow discharge and surface-treating the orifice surface of the liquid discharge head in a plasma atmosphere. Depending on the material and the degree of vacuum in the vacuum chamber, it is also possible to form a water repellent film at a low temperature of about room temperature (25 ° C.) to 200 ° C.
In the coating method, for example, a water-repellent material can be dissolved in an organic solvent and coated with a jig such as a wire bar or a doctor blade, or can be spin-coated with a spin coater, or can be coated with a spray. It can also be dip coated (dipped) in a container filled with a coating solution.

As the water-repellent material, an organic compound having a fluorine atom, particularly an organic substance having a fluoroalkyl group, an organic silicon compound having a dimethylsiloxane skeleton, and the like can be used.
As the organic compound having a fluorine atom, fluoroalkylsilane, alkane having a fluoroalkyl group, carboxylic acid, alcohol, amine and the like are preferable. Specifically, as fluoroalkylsilane, heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydrotrichlorosilane; fluoroalkyl As the alkane having a group, octafluorocyclobutane, perfluoromethylcyclohexane, perfluoro-n-hexane, perfluoro-n-heptane, tetradecafluoro-2-methylpentane, perfluorododecane, perfluoroeucosane; fluorooalkyl group Perfluorodecanoic acid, perfluorooctanoic acid as the carboxylic acid having benzene, and 3,3,4,4,5,5,5-heptafluoro-2-pentanol as the alcohol having a fluoroalkyl group; fluoroalkyl A with group The emissions, heptadecafluoro-1,1,2,2-tetrahydro-decyl amine. Examples of organosilicon compounds having a dimethylsiloxane skeleton include α, ω-bis (3-aminopropyl) polydimethylsiloxane, α, ω-bis (3-glycidoxypropyl) polydimethylsiloxane, α, ω-bis (vinyl). ) Polydimethylsiloxane and the like.

As another water-repellent material, an organic compound having a silicon atom, particularly an organic compound having an alkylsiloxane group can be preferably used.
The organic compound having an alkylsiloxane group is preferably, for example, an alkylsiloxane siloxane epoxy resin having two or more alkylsiloxane groups and cycloaliphatic epoxy groups in the molecule constituting the alkylsiloxane epoxy resin composition. Examples thereof include polymer compounds containing structural units represented by the following general formulas (a) and (b).
However, in the said general formula (a) and (b), x is 1-50, y is 2-100, n represents the integer of 2-100, respectively. R ₁ and R ₂ each independently represent a hydrogen atom or a methyl group. R ₃ and R ₄ each independently represent a methyl group or a phenyl group. R _{5 is, -CH 2 -, - CH 2} CH 2 -, or _-CH 2 CH (CH ₃₎ - represents a.

  The compound having the structural unit as described above also functions as a binder when used in combination with other water-repellent compounds. That is, it also provides a function of improving workability as a dry coating film that improves the applicability of the ink-repellent composition and increases the drying property after evaporation of the solvent.

  The thickness of the water repellent film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 μm or less, and more preferably 2 μm or less. When the thickness of the water-repellent film exceeds 5 μm, drying of the coating film is delayed, productivity may be deteriorated, mechanical durability may be impaired, and peeling may occur when wiping is performed.

  The inkjet recording method of the present invention is not particularly limited and can be appropriately selected according to the purpose. However, it is possible to transfer an original image having a high resolution at a high speed and to print without impairing the resolution of the original image. preferable. In the present invention, high-speed transfer and maintenance of resolution can be ensured by a method in which image data is compressed by a control unit such as a computer, transferred to a printer at high speed, and simple image restoration is performed on the printer side.

Specifically, when the resolution of the image to be recorded is high and the number of gradations of the image is high, the capacity of the input image increases, and the host side that handles the image to be recorded, including transfer to the recording device And the recording apparatus takes time. Therefore, in the present invention, for example, 4 × 2 × 2 pixels of the input image are regarded as one pixel. As a result, the information amount of the input image is reduced to a quarter, and the time required for recording is inevitably shortened. Note that the resolution is reduced by regarding 2 × 2 pixels of the input image as one pixel, and a countermeasure for the reduction will be described later.
On the other hand, when using a recording element array formed by integrating a plurality of recording elements, for example, an inkjet recording element array in which 16 recording element arrays shown in FIG. 14 are arranged in the main scanning direction is used. Multi-pass recording is performed. As a result, the recording elements capable of recording the same pixel of the recording medium will be described as one line (6-a) in the recording element array of FIG. It is possible to select from a total of four of −3-1 and a-4-1.

As described above, in the recording method for forming a plurality of ink dots in the same pixel, taking the recording element array shown in FIG. 14 as an example, when recording two ink dots in the same pixel, ₄ C ₂ = 6 You can take street combinations.
In addition, when using a plurality of dark and light inks, when using a plurality of recording element arrays that discharge ink of the same density, or when discharging ink having different ink droplet capacities such as large dots and small dots from the recording elements, The number of combinations increases. For example, when using a combination of dark and light ink in which the optical density of dark ink on the recording medium is substantially twice that of light ink, or a combination in which the capacity of large dots is approximately twice that of small dots Is as follows.

FIG. 15 shows a recording element array (6-a, 6-b) that can record large and small dots of light ink (A ink) and a recording element array (6-) that can record large and small dots of dark ink (B ink). 2 shows an inkjet recording element array consisting of c, 6-d). Here, when the maximum number of ink droplets that are landed on the same pixel is a maximum of two large dots and two small dots, the gradation values that can be expressed have various combinations.
Considering the combination of which recording element is used and recording on that pixel, for example, when reproducing a certain gradation value, if a recording element row passes over the recording pixel four times, which pass Thus, there are many combinations of which ink dots are recorded. Therefore, in the present invention, a combination of which nozzles are driven is stored as a table (printing element combination table: second table), and the combination is selected according to the input image.
Here, a series of recording element combinations to be actually used is selected by centrally managing the number of dots for recording dark and light inks and which recording element is used for recording from a large number of recording element combination tables described above. .
In the printing element combination table, the number of combinations that can be selected increases as the type of ink density, the type of ink droplet size, the number of printing elements, and the number of multi-pass passes increases. It is preferable to store such a limited number of combinations, which contributes to speeding up image recording. At that time, the combination can be restricted so that the total amount of ink satisfies the range of restriction in the present invention.

  FIG. 17 shows an example of the combination pattern of the recording elements stored as described above. As shown in “a” to “o” of FIG. 17, the same gradation value is recorded inside 2 × 2 pixels. Even in this case, it can be seen that the gradation value is large or small when viewed for each unit pixel. This is referred to as a density distribution in the recording pixel (density distribution pattern of the recording pixel).

The density distribution in the recording pixel is stored in the ink combination table together with the ink combination table (first table) described above, for example, in “a” to “o” shown in FIG. FIG. 18 shows an example of the ink combination table (first table) created as described above. Here, for simplicity, there are five patterns (patterns 1 to 5). The numerical values shown in FIG. 18 are the number of ink droplets to be recorded on a unit pixel, which constitutes each pattern when a maximum of 16 ink droplets are recorded on 2 × 2 recording pixels.
By selecting which one of the ink combination tables to use from the pixel values of the input image, the gradation value of the unit pixel of the input image and the gradation value of the unit pixel of the recorded image are matched by the combination table. There are cases where it is impossible. However, even if the gradations are somewhat different, the image data can be developed by reducing the amount of information of the input image, and image recording can be performed without sacrificing resolution.

In addition, there is no restriction | limiting in particular about the method of selecting the pattern of an ink combination table from the gradation value of the pixel of an input image, Although it can select suitably according to the objective, For example, the following methods are mentioned. it can.
When the unit pixel of interest (for example, the upper left pixel of 2 × 2 pixels) is more than a certain value from the total and average of the 2 × 2 pixel gradation values of the input image, 4 × 2 × 2 pixels Select a pattern according to the characteristics of However, there is a method of predicting that the other three pixels are not separated when the pixel of interest is not separated from the average value by a certain value or more.
From the series of printing element combination patterns selected in this way, the gradation value and printing element combination to be used are determined for each pixel based on the input image. When there are a plurality of combinations of gradation values, patterns, and printing element combinations that have substantially the same density, more specifically, three types of combinations A, B, and C have substantially the same gradation values. Then, when expressing the gradation value, three types of recording element combinations are used in sequence such as ABCABCABC... For each pixel.
Alternatively, it is preferable to use three types of recording element combinations at random, such as ACBCBABBBCAA. This randomization method is not particularly limited.

  Next, the configuration and operation of the ink jet recording apparatus according to this embodiment will be described. Here, a 600 dpi high-definition monochrome medical 256-ray medical X-ray transmission image using black ink and a maximum of four ink droplets can be landed on one unit pixel. A case will be described in which 2 × 2 4 unit pixels are used and a maximum of 8 ink droplets can be landed in a recording pixel.

FIG. 8 is a block diagram showing the configuration of the ink jet recording apparatus according to this embodiment.
In FIG. 8, 1 is an image input unit, 2 is an operation unit, 3 is a central control unit (CPU) that performs various processes, and 4 is a storage medium that stores various data. A control program group 4b is stored. Reference numeral 5 denotes a RAM, 6 denotes an image processing unit, 7 denotes a printer control unit that performs image output control, and 8 denotes a bus unit (bus line) that transfers various data for mutually connecting various components.

The image input unit 1 is composed of, for example, a scanner or a digital camera. The operation unit 2 includes various keys for setting various parameters and instructing start of recording. The CPU 3 controls the entire inkjet recording apparatus according to various programs in the storage medium 4.
The storage medium 4 stores a program for operating the ink jet recording apparatus in accordance with a control program and an error processing program. All the operations of the ink jet recording apparatus are performed by this program. As the recording medium 4 for storing the program, for example, ROM, FD, CD-ROM, HD, memory card, magneto-optical disk, or the like can be used.
The RAM 5 is used as a work area for various programs in the storage medium 4, a temporary save area for error processing, and a work area for image processing. The RAM 5 can also copy the various tables in the recording medium 4, change the contents of the tables, and proceed with predetermined image processing while referring to the changed tables.
The image processing unit 6 creates a discharge pattern for realizing multi-gradation by an ink jet method based on the input image. The printer unit 7 forms a dot image based on the ejection pattern created by the image processing unit 6 during image recording. The bus line 8 transmits address signals, data, control signals, and the like in the ink jet recording apparatus.

The recording element combination information 4a described above further stores data relating to the ink to be used. There is one type of ink used here, but as will be described later, light ink and dark ink may be prepared for the purpose of recording ink dots of similar colors and different densities. Useful to reproduce.
When one unit pixel is formed with a maximum of four ink dots using these inks, for example, there are various ink combination tables that can be represented by recording pixels composed of four unit pixels in which unit pixels are arranged in 2 × 2. Cross. Therefore, in the present embodiment, for each tone value, there are four types, a pattern in which the upper left density of the 2 × 2 matrix is highly biased and a pattern in which the upper right is biased, and a pattern with little bias. A total of 144 + 1 ink combination tables are used with a total of 5 types, 8 + 1 values for each recording pixel.

10 to 12 show an ink combination table (second table) according to this embodiment.
Among the numerals shown in FIGS. 10 to 12, “1” means ejection of ink droplets. Further, for convenience, in these tables, as information regarding the position of the 2 × 2 matrix, the upper left, upper right, lower left, and lower right pixels are sequentially designated as LU, RU, LL, and RL, and the unit pixels are other A group of ink combination tables whose density is higher than that of the unit pixel is expressed as a density pattern.
The density level is not completely proportional to the number of inks ejected to one pixel and the sum of the dye content of the ink. There is no practical problem with the medium.

FIG. 9 is a flowchart showing a flow of image processing in the ink jet recording apparatus according to the present embodiment.
Hereinafter, the image processing of the present invention will be described with reference to FIGS.
When the ink combination tables shown in FIGS. 10 to 12 are used, it is necessary to convert the number of gradations of the input image of 256 gradations input in step S101 of FIG. 9 into 2 + 1 values (/ 600 dpi). Therefore, the image processing unit 6 in FIG. 8 performs 2 + 1 multi-value error diffusion processing (steps S102 and S103). Here, a multilevel error diffusion method is used for this processing, but the present invention is not limited to this method. For example, an arbitrary halftone processing method such as an average density preservation method or a dither matrix method may be used. Can do.
The major difference between the multi-value error diffusion method and the normal error diffusion method is that there are a plurality of threshold values (two in this case) for binarization. These threshold values may usually be determined as the midpoint of the gradation value.

More specifically, the multivalued data is recorded in the image processing unit 6 according to the ink combination table shown in FIGS. 10 to 12 while referring to the recording element combination information 4a in the storage medium 4. It is distributed to ejection / non-ejection drive signals for the elements. Here, since the original image data is 600 dpi, the multivalued data has 2 + 1 values at 600 dpi, that is, three values of “0”, “1”, and “2” (see FIG. 9 step S103).
Therefore, in step S104, it is determined whether or not there is a difference between the average value of the recording pixel of interest and the upper left dot. For example, for a 2 × 2 recording pixel of interest (represented as (I1, J1)), the gradation value of the upper left unit pixel (i1, j1) is 2, the upper right unit pixel (i1 + 1, j1) is 1, A case where the lower left unit pixel (i1, j1 + 1) is 1 and the lower right unit pixel (i1 + 1, j1 + 1) is 0 will be described. In this case, since the density gradient information has a high density at the upper left, a density pattern of “LU” corresponding to the gradation “a” shown in FIG. 17 is selected (steps S105 and S110 in FIG. 9).
Further, since the gradation value of the 2 × 2 recording pixel itself is 4/8, the density gradient information is “LU” in the recording element combination information of density 4 (gradation value 4) shown in FIG. Based on the pattern information (that is, the combination of Nos. 45 to 48), it is determined to distribute the data. Actually, these four combinations are selected sequentially or randomly (steps S115 and S116 in FIG. 9).

By performing the above processing, the processing for one pixel of the focused recording pixel is completed. The same processing is performed for the subsequent 2 × 2 recording pixels (I2, J2).
That is, the gradation value of the upper left unit pixel (i2, j2) is 2, the upper right unit pixel (i2 + 1, j2) is 2, the lower left unit pixel (i2, j2 + 1) is 2, and the lower right unit. When the pixel (i2 + 1, j2 + 1) is 1, the density gradient information corresponds to “l” of the gradation shown in FIG. Since it is difficult to determine that this pattern belongs to any one of the LU, RU, LL, and RL, “AVE” is selected here for simplicity (step S114 in FIG. 9).
Further, since the gradation value of this recording pixel is 8/8, the pattern information (that is, No.) of the density inclination information is “AVE” from the recording element combination information of density 8 (gradation value 8) shown in FIG. .141 to 144), it is determined to distribute the data (steps S115 and S116 in FIG. 9).
Similarly, with respect to the other recording pixels, by repeating the above-described processing for the total number of pixels based on the density data of the image, binary of ejection / non-ejection for each pixel for each printing element array Is generated (steps S120 to S123 in FIG. 9).

FIG. 13 shows a multi (4) pass printing method, a print head 6-a having a print element array for ejecting A ink, a print head 6-b having a print element array for ejecting A ink, and a B ink. Each pass is recorded by a recording head 6-c having a recording element array for ejecting ink and a recording head 6-d having a recording element array for ejecting B ink.
In the present embodiment, as described above, all the pixels are sequentially processed, and printing is performed by four-pass printing by the ink jet printing apparatus having the printing element arrays of FIGS. 14, 15, and 16.

As described above, according to the present embodiment, an area where adjacent unit pixels of an input image are combined is a recording pixel, and a gradation value pattern corresponding to the input image is determined for each recording pixel. By selecting, it is possible to reduce the information amount of the image data to about one-fourth without degrading the resolution of the input image, speeding up the image recording, and reducing the burden on the control unit (CPU). be able to.
In addition, it is an ink jet recording method that records double ink droplets on at least the same unit pixel, records ink droplets having at least two types of large and small dot diameters, and records at least two types of light and dark ink droplets for similar colors. Thus, in an image recording method in which single or plural ink droplets are ejected and recorded on several unit pixels constituting a recording pixel which is a constituent unit of a recording image, complicated image processing is performed. Therefore, it is effective because the control data of the drive signals for ejection and non-ejection which are patterned is handled.
Further, by preparing a plurality of recording element combination information for the same gradation value, and recording sequentially or randomly according to different recording element combination information, various inks can be used from the same recording element for a while. The situation where it was not discharged is reduced, and at the same time, there is no situation where ink dots are formed from the same recording element over a certain area, and even when the recording head is replaced, the change in characteristics can be suppressed, and It is possible to deal with variations in the characteristics of the recording elements efficiently and effectively.
In addition, with a simple signal processing algorithm, it is possible to obtain an image with good gradation and less deterioration due to “swing”, etc. by faster and simpler processing. A good gradation image can be obtained.

  The total amount regulation method is not particularly limited and can be appropriately selected according to the purpose. However, when the input RGB signal is converted into a CMYK value, the sum of the CMYK values exceeds a certain amount. In this case, it is possible to correct the CMYK values so as to be within a certain amount, and to perform γ conversion using the γ table. Further, the order of the total amount restriction processing unit and the γ table can be reversed.

<Ink record>
The ink recorded matter recorded by the ink jet recording method of the present invention has high image quality, no bleeding, excellent stability with time, and can be suitably used for various purposes as a material on which various prints or images are recorded. .

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Example 1)
-Preparation of copper phthalocyanine pigment-containing polymer fine particle dispersion-
After sufficiently replacing the inside of the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube, and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were charged and heated to 65 ° C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, styrene macromer (trade name: AS-6, manufactured by Toagosei Co., Ltd.) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g, and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours.
After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50% by mass. Next, a part of the polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran), and the mass average molecular weight was 15,000.

  Next, 28 g of the obtained polymer solution, 26 g of copper phthalocyanine pigment, 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 30 g of ion-exchanged water were sufficiently stirred. Thereafter, the mixture was kneaded 20 times using a three-roll mill (manufactured by Noritake Company, trade name: NR-84A). The obtained paste was put into 200 g of ion-exchanged water, and after sufficiently stirring, methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a blue polymer fine particle dispersion having a solid content of 20.0% by mass. . About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 93 nm.

(Production Example 2)
-Preparation of dimethylquinacridone pigment-containing polymer fine particle dispersion-
In Production Example 1, the copper phthalocyanine pigment was changed to pigment C.I. I. A red-violet polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the pigment red 122 was used.
About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 127 nm.

(Production Example 3)
-Preparation of monoazo yellow pigment-containing polymer fine particle dispersion-
In Production Example 1, the copper phthalocyanine pigment was changed to pigment C.I. I. A yellow polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the pigment yellow 74 was used.
About the obtained polymer microparticles | fine-particles, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 76 nm.

(Production Example 4)
-Preparation of carbon black dispersion treated with sulfonating agent-
150 g of commercially available carbon black (manufactured by Degussa, “Printex # 85”) was mixed well into 400 ml of sulfolane, finely dispersed with a bead mill, 15 g of amidosulfuric acid was added, and the mixture was stirred at 140 to 150 ° C. for 10 hours. The obtained slurry was put into 1,000 ml of ion exchange water and centrifuged at 12,000 rpm to obtain a surface-treated carbon black wet cake. This carbon black wet cake was redispersed in 2,000 ml of ion exchange water, pH was adjusted with lithium hydroxide, and desalted and concentrated with an ultrafiltration membrane to obtain a carbon black dispersion having a pigment concentration of 10% by mass. . The obtained carbon black dispersion was filtered through a nylon filter having an average pore diameter of 1 μm to obtain a carbon black body. About the obtained carbon black body, the average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 80 nm.

  Next, using the polymer fine particle dispersion and the carbon black dispersion obtained in Production Examples 1 to 4, inks were produced as follows.

(Production Example 5)
-Preparation of cyan ink-
Copper phthalocyanine pigment-containing polymer fine particle dispersion 20.0% by mass of production example 1, 3-methyl-1,3-butanediol 23.0% by mass, glycerin 8.0% by mass, 2-ethyl-1,3-hexane Diol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass, Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-propanediol An appropriate amount of 5% by mass and ion-exchanged water was added to make 100% by mass, and then filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. Subsequently, the solid content was adjusted to 12% by mass using ion-exchanged water. A cyan ink was prepared as described above.

(Production Example 6)
-Preparation of magenta ink-
Dimethylquinacridone pigment-containing polymer fine particle dispersion 20.0% by mass in Production Example 2, 3-methyl-1,3-butanediol 22.5% by mass, glycerin 9.0% by mass, 2-ethyl-1,3-hexane Diol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass, Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-propanediol An appropriate amount of 5% by mass and ion-exchanged water was added to make 100% by mass, and then filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. Subsequently, the solid content was adjusted to 12% by mass using ion-exchanged water. A magenta ink was prepared as described above.

(Production Example 7)
-Preparation of yellow ink-
Monoazo yellow pigment-containing polymer fine particle dispersion of Production Example 3 20.0% by mass, 3-methyl-1,3-butanediol 24.5% by mass, glycerin 8.0% by mass, 2-ethyl-1,3-hexane Diol 2.0% by mass, FS-300 (manufactured by DuPont) 2.5% by mass, Proxel LV (manufactured by Avecia) 0.2% by mass, 2-amino-2-ethyl-1,3-propanediol An appropriate amount of 5% by mass and ion-exchanged water was added to make 100% by mass, and then filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. Subsequently, the solid content was adjusted to 12% by mass using ion-exchanged water. Thus, a yellow ink was prepared.

(Production Example 8)
-Preparation of black ink-
Carbon black dispersion of Production Example 4 20.0% by mass, 2-methyl-1,3-butanediol 22.5% by mass, glycerin 7.5% by mass, 2-pyrrolidone 2.0% by mass, 2-ethyl- 1,3-hexanediol 2.0 mass%, R- (OCH ₂ CH ₂ ) _n OH (wherein R is an alkyl group having 12 carbon atoms, n = 9) 2.0 mass%, Proxel LV ( (Avecia) 0.2 mass%, 2-amino-2-ethyl-1,3-propanediol 0.5 mass%, and an appropriate amount of ion-exchanged water are added to make 100 mass%. Filtration was performed with an 8 μm membrane filter. Subsequently, the solid content was adjusted to 12% by mass using ion-exchanged water. Thus, a black ink was prepared.

(Production Example 9)
-Preparation of dye ink set-
The components shown below were mixed, sufficiently stirred and dissolved, and then filtered under pressure using a fluoropore filter (trade name, manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm. Yellow, cyan, magenta, and A dye ink set consisting of black was prepared.
<Dye ink composition>
-Dye species-
-Yellow: C.I. I. Direct yellow 86
Cyan: C.I. I. Direct Blue 199
-Magenta: C.I. I. Acid Red 285
Black: C.I. I. Direct black 154
-Prescription-
Each dye: 4 parts by mass Glycerin: 7 parts by weight Thiodiglycol: 7 parts by mass Urea: 7 parts by mass Acetylene glycol: 1.5 parts by mass Water:・ 73.5 parts by mass

  Next, the surface tension and the viscosity of each of the inks and ink sets obtained in Production Examples 5 to 9 were measured as follows. The results are shown in Table 1.

<Measurement of viscosity>
The viscosity was measured at 25 ° C. using a R-500 viscometer (manufactured by Toki Sangyo Co., Ltd.) under conditions of cone 1 ° 34 ′ × R24, 60 rpm, 3 minutes later.

<Measurement of surface tension>
The surface tension is a static surface tension measured at 25 ° C. using a platinum plate using a surface tension measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

(Production Example 10)
-Production of support 1-
-Hardwood bleached kraft pulp (LBKP) ... 80 parts by mass-Softwood bleached kraft pulp (NBKP) ... 20 parts by weight-Light calcium carbonate (trade name: TP-121, manufactured by Okutama Kogyo Co., Ltd.) ... 10 Part by mass-Aluminum sulfate-1.0 part by mass-Amphoteric starch (trade name: Cato3210, manufactured by NSC Japan)-1.0 part by weight-Neutral rosin sizing agent (trade name: NeuSize M-10) , Manufactured by Harima Chemicals Co., Ltd.) ... 0.3 parts by mass Yield improver (trade name: NR-11LS, manufactured by Hymo Co., Ltd.) ... 0.02 parts by mass

Next, a 0.3 mass% slurry of the above composition was made with a long paper machine and machine calendered to produce a support 1 having a basis weight of 79 g / m ² . In addition, in the size press process of the papermaking process, the oxidized starch aqueous solution was applied so that the solid content was 1.0 g / m ² per side.

(Production Example 11)
−Preparation of recording paper 1−
70 parts by mass of kaolin having a particle diameter of 2 μm or less as an inorganic pigment of 97% by mass, 30 parts by mass of heavy calcium carbonate having an average particle diameter of 1.1 μm, and styrene-butadiene having a glass transition temperature (Tg) of −5 ° C. as a binder Add 8 parts by weight of copolymer emulsion, 1 part by weight of phosphate esterified starch, and 0.5 parts by weight of calcium stearate as an auxiliary agent, and then add water to prepare a barrier coating layer solution having a solid content concentration of 60% by weight. did.
This barrier coating layer solution is coated on both sides using a blade coater so that the thickness of the barrier coating layer per side is 1 μm on the prepared support 1, dried with hot air, and then super calendered. Recording paper 1 was produced.

(Production Example 12)
-Preparation of pretreatment liquid-
After mixing the components shown below and stirring them thoroughly, the components were filtered under pressure using a fluoropore filter (trade name: manufactured by Sumitomo Electric Co., Ltd.) having a pore size of 0.45 μm to prepare a pretreatment liquid. did.
<Prescription>
Polyoxyalkylene alkyl ether: 1 part by mass Pure water: 79 parts by mass 1,3-butylene glycol: 20 parts by mass

(Production Example 13)
−Preparation of recording paper 2−
The pretreatment liquid of Production Example 12 was applied to the recording paper 1 using a roller, and the pretreatment was performed by adjusting the amount of the application liquid so that the contact angle with the ink was 30 °, whereby the recording paper 2 was produced. .
For the recording paper 2 and the following recording paper, the contact angle with the ink was OCA200H manufactured by Kyowa Interface Chemical Co., Ltd., and 3 μL of ink was dropped from the microsyringe onto the pretreated recording medium. The value of the contact angle after 5 seconds was defined as the contact angle. The contact angle of the recording paper 1 was 37 °.

(Production Example 14)
−Preparation of recording paper 3−
The pretreatment liquid of Production Example 12 was applied to the recording paper 1 using a roller, and the pretreatment was performed by adjusting the amount of the application liquid so that the contact angle with the ink was 23 °, whereby the recording paper 3 was produced. .

(Production Example 15)
-Production of recording paper 4-
The pretreatment liquid of Production Example 12 was applied to the recording paper 1 using a roller, the pretreatment was performed by adjusting the amount of the application liquid so that the contact angle with the ink was 18 °, and the recording paper 4 was produced. .

(Production Example 16)
−Preparation of recording paper 5−
The pretreatment liquid of Production Example 12 was applied to the recording paper 1 using a roller, the pretreatment was performed by adjusting the amount of the application liquid so that the contact angle with the ink was 15 °, and the recording paper 5 was produced. .

(Production Example 17)
-Production of recording paper 6-
The pretreatment liquid of Production Example 12 was applied to the recording paper 1 using a roller, and the pretreatment was performed by adjusting the amount of the application liquid so that the contact angle with the ink was 13 °, whereby the recording paper 6 was produced. .

(Production Example 18)
−Preparation of recording paper 7−
Instead of the recording paper 1, an OK top coat (made by Oji Paper Co., Ltd.), which is a commercial printing paper, is used. A recording paper 7 was prepared by adjusting the amount of the coating liquid so that the contact angle was 23 ° and performing pretreatment.

(Production Example 19)
−Preparation of recording paper 8−
Instead of recording paper 1, commercial coated paper Mirror Coat Platinum (manufactured by Oji Paper Co., Ltd.) was used. The recording paper 8 was produced by adjusting the amount of the coating solution so that the contact angle was 23 ° and performing pretreatment.

  Next, with respect to the recording paper 1, OK top coat (manufactured by Oji Paper Co., Ltd.) and mirror coat platinum (manufactured by Oji Paper Co., Ltd.), the amount of pure water transferred by a dynamic scanning absorption meter is measured as follows. did. The results are shown in Table 2.

<Measurement of the amount of pure water transferred by dynamic scanning absorption meter>
About each recording paper, the transfer amount of the pure water was measured using the dynamic scanning liquid absorption meter (K350 series D type, Kyowa Seiko Co., Ltd. make). The transfer amount at the contact time of 100 ms and the contact time of 400 ms was determined by interpolation from the measured value of the transfer amount at the contact time adjacent to each contact time. The measurement was performed under environmental conditions of 23 ° C. and 50% RH.

Example 1
Next, image recording was performed as follows using the ink set 1 made of the black ink, the yellow ink, the magenta ink, and the cyan ink manufactured according to Manufacturing Examples 5 to 8 and the recording paper 2.
<Image recording>
Printing was performed at an image resolution of 600 dpi using a drop-on-demand printer prototype having 300 dpi and a nozzle resolution of 384 nozzles. The large droplet size was 20 pl, the medium droplet size was 10 pl, and the small droplet size was 2 pl. In addition, the total amount regulation of the secondary color was set to 140%, and the adhesion amount regulation was implemented. During solid printing, solid images and characters were printed so that the total amount of ink (maximum adhesion amount) in 300 dots square did not exceed 15 g / m ² .
Average measured value of the ink total amount, 15 g / ^{m 2} in case of using a large droplet, 12 g / ^{m 2} in case of using a medium droplet, was 10 g / ^{m 2} in case of using the droplet.
FIG. 20 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

(Example 2)
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 3. FIG. 20 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

Example 3
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 4. FIG. 21 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

Example 4
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 5. FIG. 21 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

(Example 5)
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 6. FIG. 21 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

Example 6
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 7.

(Example 7)
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 8.

(Comparative Example 1)
In Example 1, image recording was performed in the same manner as in Example 1 except that the recording paper 2 was changed to the recording paper 1. FIG. 20 shows the results of dot images of large droplet size, medium droplet size, and small droplet size.

(Comparative Example 2)
In Comparative Example 1, image recording was performed in the same manner as Comparative Example 1 except that the ink set 1 was changed to the dye ink (water-soluble colorant) set of Production Example 9.

(Comparative Example 3)
In Example 1, image recording was performed in the same manner as in Example 1 except that the ink set 1 was changed to the dye ink (water-soluble colorant) set of Production Example 9.

  Next, Examples 1 to 7 and Comparative Examples 1 to 3 were evaluated for image density, small droplet banding, and large droplet image blur as follows. The results are shown in Table 3.

<Image density>
The optical density of the solid image portion of the magenta ink of the example and the comparative example was measured with X-Rite 932, and evaluated according to the following criteria.
〔Evaluation criteria〕
◎: Magenta image density is 1.6 or more ○: Magenta image density is 1.3 or more △: Magenta image density is 1.0 or more ×: Magenta image density is less than 1.0

<Small banding>
Gray halftone solid images were printed using small droplets, and the occurrence of banding (streaks) was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
○: No banding or almost inconspicuous, uniform image ×: Banding is conspicuous and inferior in uniformity

<Large drop image blur>
Printing was performed using large droplets, and the color boundaries of the image portions and the degree of blurring of fine lines in the examples and comparative examples were visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
A: Sharp printing without blurring. B: Slight blurring is observed, but it is a level that does not matter at all. B: Blurring is observed, but the image quality is not impaired. Clear blurring is observed, and the level is completely inappropriate as an image

From FIG. 20, FIG. 21, and the results of Table 3, in Comparative Example 1 using the recording paper 1 with no pretreatment liquid and excellent ink absorption, the dot shape is ideal. Since the dot diameter relative to the amount is too small, a large amount of ink (multiple drops) must be used when creating the image.
On the other hand, in Examples 1 to 7, even with the same droplet size, the droplet diameter can be made larger than that in Comparative Example 1 (particularly when medium and small droplets are used). It was confirmed that a good image was obtained.
Since the large droplet size in Examples 3 to 5 is too large (the amount of adhesion is too large), the dot shape is deteriorated (see the result of large droplet image blur in Table 3), but the ink is small in the medium droplet and the small droplet. It was found that a good image with good embedding can be formed even with the amount.

The ink jet recording method and the ink jet recording apparatus of the present invention use a recording medium having a texture close to that of general commercial printing paper, or a general commercial paper and publishing paper that satisfies a predetermined condition, so-called “ It is possible to provide a glossy recorded image with excellent print quality that is free of blurring, feathering, and bleeding in the peripheral portions of characters and images with good cutting.
The ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method, and is particularly preferably applied to, for example, an ink jet recording printer, a facsimile machine, a copying machine, a printer / fax / copier multifunction machine, and a printing machine. can do.

FIG. 1 is a schematic view showing an example of the ink cartridge of the present invention. FIG. 2 is a schematic view including the case of the ink cartridge of FIG. FIG. 3 is an explanatory perspective view of the ink jet recording apparatus in a state where the cover of the ink cartridge loading unit is opened. FIG. 4 is a schematic configuration diagram illustrating the overall configuration of the inkjet recording apparatus. FIG. 5 is a schematic enlarged view showing an example of an inkjet head in the inkjet recording apparatus of the present invention. FIG. 6 is an element enlarged view showing an example of an ink jet head in the ink jet recording apparatus of the present invention. FIG. 7 is an enlarged cross-sectional view of a main part showing an example of an ink jet head in the ink jet recording apparatus of the present invention. FIG. 8 is a block diagram showing the configuration of the ink jet recording apparatus of the present invention. FIG. 9 is a flowchart showing a flow of image processing in the ink jet recording apparatus of the present invention. FIG. 10 is an ink combination table (second table) according to the present embodiment. FIG. 11 is an ink combination table (second table) according to the present embodiment. FIG. 12 is an ink combination table (second table) according to the present embodiment. FIG. 13 is a diagram showing a multi (4) pass recording method. FIG. 14 is a diagram illustrating a printing element array. FIG. 15 is another diagram showing a printing element array. FIG. 16 is still another diagram showing a printing element array. FIG. 17 is an example of a combination pattern of recording elements. FIG. 18 is an example of an ink combination table (first table). FIG. 19 is a side sectional view showing an example of the pretreatment liquid coating apparatus in the ink jet recording apparatus of the present invention. FIG. 20 is a diagram illustrating the results of the Dodd images of Comparative Example 1 and Examples 1-2. FIG. 21 is a diagram illustrating the results of dot images of Examples 3 to 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Frame 20 Flow path plate 30 Nozzle plate 40 Base 50 Multilayer piezoelectric element 60 Vibrating plate 70 Adhesive layer 101 Apparatus main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading part 111 Upper cover 112 Front surface 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Paper placement unit 142 Paper 144 Separation pad 151 Conveying belt 152 Counter roller 156 Charging roller 157 Conveying roller 158 Densation roller 171 Separating claw 172 Paper ejection roller 173 Paper ejection roller 181 Double-sided paper feed unit 201 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge exterior 301 Polishing unit 302 Polishing roll 303 Leaning roll 401 Pretreatment liquid 402 Film thickness control roller 403 Pumping roller 404 Application roller 405 Counter roller 406 Paper 407 Paper feed roller 408 Paper feed tray 411, 412, 413, 414, 415, 416 Paper feed roller 417 Paper 418 Paper feed roller 420 Recording head 421 Ink cartridge 422 Carriage shaft 423 Carriage 442 Pretreatment liquid container

Claims (21)

A pretreatment step of performing pretreatment by applying a pretreatment liquid containing at least a surfactant to a recording medium having at least one barrier coating layer on at least one surface of the support;
At least water-dispersible colorant is applied to ink to stimulation comprising at least look including an ink jetting step of recording an image on a recording medium after preprocessing by ejecting the ink,
The barrier coating layer comprises at least one of oxidized starch, esterified starch, enzyme-modified starch, and cationized starch;
The inkjet recording method , wherein the surfactant contains a polyoxyalkylene alkyl ether .   The inkjet recording method according to claim 1, wherein the stimulus is at least one selected from heat, pressure, vibration, and light. The recording medium has a pure water transfer amount of 35 ml / m ² or less at a contact time of 100 ms as measured by a dynamic scanning absorption meter, and a pure water transfer amount of 40 ml / m ² or less at a contact time of 400 ms. Item 3. The ink jet recording method according to any one of Items 1 to 2.   The ink jet recording method according to any one of claims 1 to 3, wherein the contact angle by the ink droplet dropping method on the recording medium after the pretreatment is 15 ° or more and 35 ° or less after 5 seconds of ink dropping.   The ink jet recording method according to claim 1, wherein the pretreatment liquid is applied by bringing the pretreatment means into contact with the recording medium.   6. The ink jet recording method according to claim 5, wherein the pretreatment means is a roller.   7. The ink jet recording method according to claim 1, wherein any one of an ink having a droplet size of 20 pl or more and a combination of an ink having a droplet size of 20 pl or more and an ink having a droplet size of less than 20 pl is used. The ink jet recording method according to any one of claims 1 to 7, wherein a maximum adhesion amount of the ink is 15 g / m ² or less.   9. The ink jet recording method according to claim 1, wherein the water dispersible colorant is any one of a pigment and colored fine particles, and the volume average particle diameter of the colorant is 0.01 to 0.16 [mu] m.   The ink jet recording method according to claim 1, wherein the viscosity of the ink at 25 ° C. is 3 mPa · s or more.   The ink jet recording method according to any one of claims 1 to 10, wherein the ink contains a penetrant, and the penetrant is any one of a polyol compound having 8 or more carbon atoms and a glycol ether compound.   The inkjet recording method according to claim 11, wherein the polyol compound having 8 or more carbon atoms is at least one of 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. The ink contains a surfactant, and the surfactant is at least one selected from the following general formulas (I), (II), (III), (IV), (V), and (VI) The inkjet recording method according to any one of claims 1 to 12.
R ¹ —O— (CH ₂ CH ₂ O) _h CH ₂ COOM —General Formula (I)
In the general formula (I), ^{R 1} represents an alkyl group. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.
In the general formula (II), ^{R 2} represents an alkyl group. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.
In the general formula (III), ^{R 3} is represents a hydrocarbon group. k represents an integer of 5 to 20.
_{^{R 4 - (OCH 2 CH 2}} ) j OH ··· formula (IV)
In the general formula (IV), ^{R 4} represents a hydrocarbon group. j represents an integer of 5 to 20.
In the general formula (V), ^{R 6} represents a hydrocarbon group. L and p each represent an integer of 1 to 20.
However, in said general formula (VI), q and r represent the integer of 0-40, respectively.   The inkjet recording method according to any one of claims 1 to 13, wherein the ink contains a wetting agent, and the wetting agent is at least one selected from a polyol compound, a lactam compound, a urea compound, and a saccharide.   The polyol compound is glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4 -Butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 1,2,4-butanetriol, 1 The inkjet recording method according to claim 14, which is at least one selected from 1,2,6-hexanetriol, thiodiglycol, pentaerythritol, trimethylolethane, and trimethylolpropane.   The inkjet recording according to any one of claims 14 to 15, wherein the lactam compound is at least one selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and ε-caprolactam. Method.   The inkjet recording method according to claim 14, wherein the urea compound is at least one selected from urea, thiourea, ethyleneurea, and 1,3-dimethyl-2-imidazolidinone.   The inkjet recording method according to any one of claims 14 to 17, wherein the saccharide is at least one selected from maltose, sorbitol, gluconolactone, and maltose.   The inkjet recording method according to claim 14, wherein the content of the wetting agent in the ink is 10 to 50% by mass.   The ink jet recording method according to claim 1, wherein the ink is at least one selected from cyan ink, magenta ink, yellow ink, and black ink. A recording medium having a support and at least one barrier coating layer on at least one surface of the support;
Pretreatment means for pretreating the recording medium by applying a pretreatment liquid containing at least a surfactant;
At least water-dispersible colorant is applied to ink to stimulation containing, at least it has the ink flying means for recording an image on a recording medium after preprocessing by ejecting the ink,
The barrier coating layer comprises at least one of oxidized starch, esterified starch, enzyme-modified starch, and cationized starch;
The inkjet recording apparatus , wherein the surfactant includes a polyoxyalkylene alkyl ether .