JP5293990B2 - Recording ink, recording method, and recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide recording ink having excellent fixability onto a recording medium, image density and long storage stability of the ink, forming a high quality image not only on regular paper and paper for inkjet but also on coated paper for commercial printing with a poor water absorbing property, a recording method and a recording apparatus. <P>SOLUTION: The recording ink contains at least water, a water-soluble organic solvent, a surfactant and carbon black having a hydrophilic group at the surface, wherein the detection amount of the fumic acid eluted in a 20 wt.% dispersion of the carbon black is 5.0 to 20.0 based on the maximum light absorbance measured at a 230 to 260 nm wavelength. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a recording ink particularly suitable for inkjet recording, a recording method and a recording apparatus using the ink.

Dyes are mainly used as colorants for ink jet recording inks, but the dye inks are inferior in water resistance and weather resistance, and are liable to spread on plain paper. In order to improve these drawbacks, inks using pigments such as carbon black have been proposed.
Pigment inks are excellent in water resistance and weather resistance, and can record images with little bleeding, but have a problem of poor fixability. Therefore, attempts have been made to improve the fixing property by adding various resins.

  Patent Document 1 (Japanese Patent No. 3489289) proposes a recording liquid containing carbon black and a soap-free emulsion. The recorded matter obtained using the recording liquid used in this example is a carbon black contained in the recording liquid, although the resin emulsion forms a film after the ink is dried to fix the pigment so that the pigment is fixed. Is dispersed by a surfactant and does not have a hydrophilic group directly on the surface. Such a surfactant-dispersed recording liquid has the disadvantages that the surfactant adsorbed on the pigment surface with time is desorbed and the dispersibility is likely to deteriorate, resulting in increased viscosity and aggregation.

  Patent Document 2 (Japanese Patent No. 3405817) describes a method of oxidizing carbon black with hypohalogen. Since the water-dispersible functional group can be introduced on the surface by oxidizing the carbon black, the dispersion stability is better than the surfactant dispersion. However, it is known that humic acid is generated by the oxidation treatment of carbon black, and the dispersion liquid has a tendency to lower the pH with time, resulting in a decrease in dispersion stability and deterioration of members inside the recording apparatus using ink. Will be caused.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-204079) describes an ink composition that contains two or more types of resins and uses a pigment that can be dispersed or dissolved in water without a dispersant. Here, carbon black that can be dispersed or dissolved in water without a dispersant contained in the ink composition is oxidized with hypochlorous acid or ozone, but measures against a decrease in pH over time due to humic acid elution are taken. Therefore, it is not satisfactory in terms of ink storage stability.

  Patent Document 4 (Japanese Patent Application Laid-Open No. 11-349309) pays attention to the fact that humic acid is contained in oxidized carbon black, and if the extracted humic acid concentration is 1 or less in absorbance, it can be detected with a nozzle or a nib. It is described that it is possible to suppress clogging due to the generation of solid matter and to exhibit excellent characteristics. When the recording liquid contains a large amount of humic acid, the pH tends to decrease with time and storage stability tends to deteriorate, but according to the study by the present inventors, the presence of a certain amount of humic acid on the surface of the recording medium It has been found that there is an effect of rapidly agglomerating and a recorded image having a high density can be obtained.

Japanese Patent No. 3489289 Japanese Patent No. 3405817 JP 2004-204079 A JP 11-349309 A

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is excellent in fixability and image density on a recording medium and excellent in long-term storage stability of ink, and is not only used for plain paper and inkjet paper but also for commercial printing with poor water absorption. Another object of the present invention is to provide a recording ink, a recording method, and a recording apparatus capable of forming a high-quality image even on coated paper.

The feature of the present invention is that a certain amount of humic acid eluted from carbon black is contained in the ink, thereby increasing the ink thickening at the time of water evaporation, and quickly aggregating carbon on the recording medium to form an image. The concentration can be obtained.
Ink containing humic acid has a tendency to decrease in pH over time, but it has become possible to maintain the storage stability of the ink by including a pH buffer in the ink.
In addition, inkjet printing does not require plate making, so printing can be performed easily, and water-based inks have a low environmental impact, so high-quality printing equivalent to commercial printing such as offset printing and gravure printing can be performed with aqueous inkjet. However, it has been desired in recent years. Paper used for offset printing and gravure printing is coated with inorganic pigments such as calcium carbonate and kaolin, but it does not have a water-absorbing layer like paper for inkjet use, so it absorbs water-based ink. Is inferior. It has been found that the ink of the present invention allows high-quality printing even on a recording medium with poor water-based ink absorption because the color material quickly aggregates and dries on the recording medium.

That is, the said subject is solved by the following (1)-(21) of this invention.
(1) “At least water, a water-soluble organic solvent, a surfactant, and carbon black having a hydrophilic group on the surface are contained, and the detected amount of humic acid eluted in a 20 Wt% dispersion of the carbon black is 230 5.0-20.0 der the maximum absorbance measured at a wavelength of ~260nm is, recording ink alkali metal content in the ink is characterized in der Rukoto than 1500ppm or less 100ppm "
(2) “Recording ink according to item (1), which contains 5 to 15% by mass of the carbon black”,
(3) Item (1), wherein when the water evaporation rate with respect to the total ink weight is 35 to 40 wt%, the degree of increase in viscosity relative to the initial viscosity is 5.0 times or more and does not exceed 550 times. Or the recording ink according to item (2) ",
(4) "The recording ink according to any one of (1) to (3) above, which contains a pH buffer";
(5) "The recording ink according to any one of (1) to (4) above, wherein the pH buffer is an organic pH buffer selected from Good buffers";
(6) Any one of the above items (1) to (5), wherein the volume average particle diameter of carbon black having a hydrophilic group dispersed in water is 60 to 200 nm. Recording inks described in "
(7) “The recording ink according to any one of (1) to (6) above, which includes resin fine particles having a volume average particle diameter of 50 to 200 nm”;
(8) “The recording ink according to any one of items (1) to (7), wherein at least a part of the hydrophilic group terminal of the carbon black is substituted with an alkali metal” ,
( 9 ) "The recording ink according to any one of (1) to ( 8 ), wherein the recording ink has a viscosity at 25 ° C of 6 to 20 mPa · s",
( 10 ) “An ink jet recording method for performing recording using the ink according to any one of items (1) to ( 9 ), wherein the ink discharge opening of the recording head is formed. A recording method characterized in that an ink repellent layer is formed on
( 11 ) "The recording method according to item ( 10 ), wherein the ink repellent layer is made of a fluorine-based material or a silicone-based material";
( 12 ) “The recording method according to item ( 10 ), wherein the ink-repellent layer has a surface roughness Ra of 0.2 μm or less”,
( 13 ) “The cross-sectional area in the plane perpendicular to the center line of the opening in the vicinity of the opening of the ink-repellent layer is formed so as to gradually increase as the distance from the surface of the substrate increases. The recording method according to item ( 10 ) above ”,
( 14 ) “The recording method according to ( 10 ), wherein the ink repellent layer has a critical surface tension γc of 5 to 40 mN / m”,
( 15 ) "Recording medium (recording medium) having a support and a coating layer on at least one surface of the support using the ink according to any one of (1) to ( 9 ). Recording method characterized by recording in
( 16 ) "The recording medium of the ink at a contact time of 100 ms when the ink according to any one of (1) to ( 9 ) is measured with a dynamic scanning absorptiometer at 23 ° C and 50% RH. a transfer amount is 2~40ml / ^{m 2} to, and recording method transfer amount to the recording medium of the ink at a contact time of 400ms is characterized in that it is a 3~50ml / ^{m 2} ",
( 17 ) “The recording medium is composed of at least a base material and a coating layer, and the solid content adhesion amount of the coating layer is 0.5 to 20.0 g / m ^2. The recording method according to item ( 15 ) or ( 16 ) ",
(18) "the recording medium, the second (15) section to the (17) recording method according to any one of Items basis weight is characterized by a 50 to 250 g / ^{m 2",}
( 19 ) “At least ink jetting means for recording an image by applying a stimulus to the recording ink according to any one of (1) to ( 9 ) and causing the recording ink to fly. Inkjet recording apparatus, wherein the stimulus is at least one selected from heat (temperature), pressure, vibration and light ",
( 20 ) "Inkjet recording apparatus using the recording method according to any one of ( 10 ) to ( 18 )",
( 21 ) "A method for evaluating a recording ink comprising at least water, a water-soluble organic solvent, a surfactant, and a carbon black having a hydrophilic group on its surface, and is eluted in a 20 Wt% dispersion of the carbon black. The detected amount of humic acid is 5.0 to 20.0 in terms of the maximum absorbance measured at a wavelength of 230 to 260 nm, and the water absorption depends on whether the amount of alkali metal contained in the ink is 100 ppm or more and 1500 ppm or less. "A method for evaluating a recording ink, characterized by evaluating whether a high-quality image can be formed even on coated paper having poor properties ".

  According to the present invention, the fixing property and image density on the recording medium are excellent, and the long-term storage stability of the ink is excellent, and not only for plain paper and inkjet paper but also for commercial printing with poor water absorption. It is possible to provide a recording ink, a recording method, and a recording apparatus that can form a high-quality image even on coated paper.

(Ink for recording)
The recording ink of the present invention contains at least water, a water-soluble organic solvent, a penetrating agent, and carbon black having a hydrophilic group on the surface, and the detection amount of humic acid eluted from the carbon black is 230 to 260 nm. The maximum absorbance measured by wavelength is 5.0 to 20.0.

Humic acid is an organic acid generated when carbon black is oxidized, and the composition itself is uncertain, but it has an aromatic ring and a plurality of functional groups such as a carboxyl group and a hydroxyl group, and has a wavelength of 230 to 260 nm. Has maximum absorption at wavelength. Therefore, the concentration can be quantified by measuring the absorbance.
Humic acid is generated in the process of oxidizing carbon, but it is removed as much as possible by washing at the time of dispersion preparation. However, when carbon having a high degree of oxidation and bulk is used, it cannot be removed by washing, and humic acid tends to remain in the carbon.
When stored as ink, the remaining humic acid is eluted, causing a decrease in pH. Ink may cause aggregation and thickening due to a decrease in pH, and may corrode the members used in the ink flow path inside the printer. When printing is performed using such ink, normal ejection may occur. I can't get it.
On the other hand, when humic acid remains in the carbon, it is considered that a high-density image can be obtained because the pH is lowered and aggregation / thickening occurs when water in the ink evaporates. Therefore, it is preferable that humic acid remains at a certain concentration.
The characteristics of the carbon black to meet the scope of claim 1, it is preferable that the DBP oil absorption is 50 to 300 m ² / g, more preferably 100 to 300 m ² / g. The DBP oil absorption amount is obtained from the DBP amount necessary for dripping DBP (dibutyl phthalate) into carbon black and allowing it to enter the voids of carbon to fill the gap per 100 g of carbon black.

As a method for quantifying humic acid in ink eluted from carbon black, first, carbon black was recovered by separating additives such as a surfactant, a rust inhibitor and an antifoaming agent by means such as column chromatography. It vacuum-dried with the dryer of 50 degreeC, and after water and a solvent were fully evaporated, it diluted so that it might become 20 wt% with water. 50 g of this diluted solution is taken in a beaker and passed through an ultrafiltration membrane (Pellicon Biomax 50 manufactured by MILLIPORE) for 30 minutes to obtain a brown liquid. This liquid was diluted 10 times with ion-exchanged water and measured at a wavelength of 230 to 260 nm with a spectrophotometer (U-3310 manufactured by Hitachi High-Tech) using a quartz cell (optical path length 10 mm), and the maximum absorbance obtained. Can be multiplied by 10 to obtain the humic acid concentration.
Thus, the case where the light absorbency measured is in the range of 5.0-20.0 is preferable, and the range of 10.0-15.0 is more preferable. If it is less than 5.0, the image density on a recording medium such as plain paper or coated paper may be inferior. In addition, when it is larger than 20.0, the pH decreases with time, tends to cause aggregation and thickening after long-term storage, and the ink thickening rate at the time of moisture evaporation tends to increase. Stability will be inferior. That is, it was found that a high density recording image can be obtained when a certain amount of humic acid is present in the ink.
This is presumably because the solid content quickly thickens and aggregates when moisture evaporates on the surface of the recording medium.

  Regarding the relationship between the thickening behavior at the time of water evaporation and the image density, when the amount of water evaporation with respect to the total weight of the ink is 35 to 40% by mass, the viscosity increase with respect to the initial viscosity is 5.0 times or more and does not exceed 550 times. It was found that when the above condition was satisfied, the image density of the recorded matter was excellent with excellent ejection stability.

  Regarding the relationship between the humic acid concentration in the ink and the ink thickening behavior during water evaporation, the higher the humic acid concentration, that is, the higher the absorbance value measured by the measurement method, the higher the rate of increase in viscosity associated with water evaporation. Thus, the lower the humic acid concentration, that is, the lower the absorbance value, the lower the viscosity increase rate associated with water evaporation.

In addition, the amount of alkali metal contained in the ink also affects the ink thickening behavior when moisture evaporates. Lithium, sodium, and potassium are mainly contained in the ink as alkali metals, and most of them are added as neutralizing agents for the surface hydrophilic groups of carbon black, neutralizing agents for resin emulsions, etc. It may be contained in an activator or other additives.
The content of alkali metal in the ink is preferably from 100 ppm to 1500 ppm, and more preferably from 200 ppm to 1200 ppm. If the alkali metal content is less than 100 ppm, the image density tends to be low, and if it exceeds 1500 ppm, the ink storage and discharge properties tend to deteriorate.

  The carbon black having a hydrophilic group used in the recording ink of the present invention is produced by a known carbon black, such as a channel method, an oil furnace method, a furnace method, an acetylene black method, or a thermal black method. What was manufactured can be used. In addition, since the production amount of channel black has decreased in recent years and the variety is limited, furnace black having a larger variety is actively used.

As the type of the carbon black, a general carbon black produced by the above production method can be used. In particular, the primary particle size is 10 to 40 nm, and the specific surface area by the BET method is 50 to 300 m ² / g. The DBP oil absorption is preferably 40 to 150 ml / 100 g.
As such, for example, # 2700, # 2650, # 2600, # 2450B, # 2400B, # 2350, # 230, # 1000, # 990, # 980, # 970, # 960, # 950, # 900 , # 850, # 750B, MCF88, # 650B, MA600, MA77, MA7, MA8, MA11, MA100, MA100R, MA100S, MA220, MA230, MA200RB, MA14, # 52, # 50, # 47, # 45, # 45L # 44, # 40, # 33, # 32, # 30, # 25, # 20, # 10, # 5, # 95, # 85, CF9, # 260 (above, manufactured by Mitsubishi Chemical),
Raven700, 5750, 5250, 5000, 3500, 1255 (above Colombia),
Regal400R, 330R, 660R, MoguL, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch1400 (above, manufactured by Cabot),
Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A 4 (above, Degussa),
Toka Black # 8500, # 8300, # 7550, # 7400, # 7360, # 7360, # 7350, # 7270, # 7100 (above Tokai Carbon),
Shiyo Black N110, Same N220, Same N234, Same N339, Same N330, Same N326, Same N330T, Same MAF, Same N550 (above made by Cabot Japan), etc. can be used, but are not limited to these. Absent.

The carbon black can be surface-modified, and at least one hydrophilic group can be bonded to the surface of the carbon black directly or through another atomic group, and can be stably dispersed without using a dispersant. it can.
The surface modification method is not particularly limited and may be appropriately selected according to the purpose. For example, vapor phase oxidation using an oxidizing gas such as ozone or liquid phase oxidation using a liquid oxidizing agent may be used. Can be mentioned. Examples of the liquid oxidant include hydrogen peroxide, iodine water, hypochlorite, chlorite, nitric acid, permanganate, dichromate, and persulfate.

As the hydrophilic group, for example, —COOM, —SO ₃ M, —PO ₃ HM, —PO ₃ M ₂ , —SO ₂ NH ₂ , —SO ₂ NHCOR (wherein M is a hydrogen atom, an alkali Represents metal, ammonium, or organic ammonium, and R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group that may have a substituent, or a naphthyl group that may have a substituent. It is done. Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface.
“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 trimethylammonium, mono- to triethylammonium, and mono-to-trimethanolammonium, and alkali metals such as potassium and sodium are preferably used from the viewpoint of obtaining a high image density.

  The volume average particle size in a state where the carbon black having a hydrophilic group is dispersed in water is preferably 60 to 200 nm, and more preferably 80 to 180 nm. When the volume average particle size is less than 60 nm, a sufficient image density cannot be obtained, and when it exceeds 200 nm, clogging tends to occur at the nozzle, and the discharge performance may deteriorate. The volume average particle diameter can be measured with Microtrac UPA (Nikkiso Co., Ltd.).

  The content of the carbon black having a hydrophilic group in the ink is preferably 5 to 15% by mass, and more preferably 6 to 12% by mass. If the content in the ink is less than 5% by mass, a sufficient image density may not be obtained, and if it exceeds 15% by mass, the ink viscosity may increase and the ejection stability may deteriorate.

  There is no restriction | limiting in particular as a water-soluble organic solvent used for the recording ink of this invention, According to the objective, it can select suitably, For example, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol, propylene glycol, dipropylene glycol , Tripropylene glycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4 butanediol, 3-methyl-1,3-butanediol, 1,5 pentanediol, tetra Ethylene glycol, 1,6 hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, polyethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4 -Butanetriol, 1, 2, 3-bu Polyhydric alcohols such as Ntriol and Petriol; many 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, propylene glycol 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, 2-pyrrolidone, 1,3 -Nitrogen-containing heterocyclic compounds such as dimethylimidazolidinone and ε-caprolactam; formamide, N-methylform Amides such as muamide, formamide and N, N-dimethylformamide; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine; sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol; Examples include propylene carbonate and ethylene carbonate. These may be used alone or in combination of two or more.

  Among these, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1 from the viewpoint of obtaining excellent effects on solubility and prevention of poor jetting characteristics due to water evaporation , 3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, tetraethylene glycol, 1,6-hexanediol, 3 -Methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, thiodiglycol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxy Chill-2-pyrrolidone is preferred.

  The content of the water-soluble organic solvent in the recording ink is preferably 15 to 40% by mass, and more preferably 20 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.

As the surfactant, one type selected from anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and fluorosurfactants may be used alone or in admixture of two or more. Can do.
Anionic surfactants include alkyl allyl, alkyl naphthalene sulfonate, alkyl phosphate, alkyl sulfate, alkyl sulfonate, alkyl ether sulfate, alkyl sulfosuccinate, alkyl ester sulfate, alkyl benzene sulfonate, Alkyl diphenyl ether disulfonate, alkyl aryl ether phosphate, alkyl aryl ether sulfate, alkyl aryl ether ester sulfate, olefin sulfonate, alkane olefin sulfonate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl Examples include ether sulfate ester salts, ether carboxylates, sulfosuccinates, α-sulfo fatty acid esters, fatty acid salts, condensates of higher fatty acids and amino acids, and naphthenates. That.
Examples of nonionic surfactants include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan fatty acid esters.
Examples of the cationic surfactant include alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, alkylpyridinium salts, imidazolinium salts, sulfonium salts, phosphonium salts, and the like. Can be mentioned.
Examples of the amphoteric surfactant include imidazoline derivatives such as imidazolinium betaine, dimethylalkyl lauryl betaine, alkylglycine, and alkyldi (aminoethyl) glycine.

  As the fluorine-based surfactant, the following structural formulas (I) to (III) can be preferably used.

（ｍは０〜１０の整数を表わし、ｎは１〜４０の整数を表わす。）

(M represents an integer of 0 to 10, and n represents an integer of 1 to 40.)

（ＲｆはＣＦ_３またはＣＦ_２ＣＦ_３を表わし、ｎは１〜４、ｍは６〜２５、ｐは１〜４の整数を表わす。）

(Rf represents CF ₃ or CF ₂ CF ₃ , n represents 1 to 4, m represents 6 to 25, and p represents an integer of 1 to 4)

（ｑは１〜６の整数を表わし、ＲｆはＣＦ_３またはＣＦ_２ＣＦ_３を、Ｒ_１はＳＯ_３−を、Ｒ_２はＮＨ_４ ^＋を表わす。）

(Q represents an integer of 1 to 6, Rf is a CF ₃ or _CF 2 CF _{3, R 1} is SO ₃ - and, _{R 2} represents _NH ^{4 +.)}

Examples of the fluorosurfactant include commercially available Surflon S-111, S-112, S-113, S121, S131, S132, S-141, and S-145 (manufactured by Asahi Glass Co., Ltd.) Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431, FC-4430 (manufactured by Sumitomo 3M), MegaFuck F-470, F -1405, F474 (Dainippon Ink Chemical Co., Ltd.), Zonyl FS-300, FSN, FSN-100, FSO (DuPont), F-Top EF-351, 352, 801, 802 (Gemco) Can be mentioned.
Particularly preferred are nonionic surfactants and fluorosurfactants.

In the ink of the present invention, resin fine particles can be added. The resin fine particles exist in a state where a water-insoluble resin is dispersed in water. When the solvent evaporates, the resin fine particles are fused together to form a film and have an effect of fixing the colorant on the medium. . Further, when the solvent evaporates, it has the property of thickening and agglomerating, suppressing the penetration of the coloring component, obtaining a high image density, and also preventing the show-through.
Resin components include acrylic resin, vinyl acetate resin, styrene-butadiene resin, vinyl chloride resin, acrylic-styrene resin, acrylic silicone resin, butadiene resin, styrene resin, urethane resin, acrylic urethane resin, etc. Is mentioned. The amount of the resin emulsion added is preferably 0.1 to 40% by weight of the ink, more preferably 1 to 25% by weight. If the resin fine particle content is less than 0.1% by mass, sufficient fixability may not be obtained. If the resin fine particle content exceeds 40% by mass, the composition has a high solid content and a small amount of solvent, resulting in poor storage stability. In some cases, the nozzles are liable to be dried or solidified, resulting in a decrease in ejection performance.

  The addition amount of the resin fine particles to the pigment is preferably 0.05 to 1.2 parts by mass, and more preferably 0.2 to 1.0 parts by mass with respect to 1 part by mass of the pigment. If the resin fine particle is less than 0.05 parts by mass, sufficient fixability may not be obtained, and if it exceeds 1.2 parts by mass, the storage stability may be deteriorated or the dischargeability may be reduced. is there.

  In the present invention, a diol compound having 7 to 11 carbon atoms can be used as the penetrant. If the number of carbon atoms is less than 7, sufficient permeability cannot be obtained, and the recording medium is soiled during double-sided printing, or the ink spread on the recording medium is insufficient and the filling of the pixels becomes worse. A decrease in image density may occur, and if it exceeds 11, storage stability may decrease.

As the diol compound, for example, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and the like are suitable.
The addition amount of the diol compound is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass. If the amount added is too small, the permeability of the ink to the paper will be inferior, the roller will be rubbed with a roller during conveyance, and the ink will be applied to the conveyance belt when the recording surface of the recording medium is reversed for double-sided printing. It may cause stains and may not be compatible with high-speed printing or double-sided printing. On the other hand, if the addition amount is too large, the print dot diameter becomes large, the line width of the character becomes wide, and the image sharpness may decrease.

In the present invention, conventionally known phosphate buffer solution, acetate buffer solution, ethanolamine buffer solution, borate buffer solution, citrate buffer solution, tartrate buffer solution, Good buffer solution to alleviate the pH drop of the ink during long-term storage. Of these, Good buffer is particularly preferable.
Good buffer is a zwitterion amino acid such as N-substituted taurine and N-substituted glycine, and is known as an organic buffer suitable for biochemistry.
The specific structure of the Good buffer solution is shown below.

The preferable amount of the pH buffering agent is 0.001 to 5.0% by weight, more preferably 0.005 to 1.0% by weight.
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, light And stabilizers.

  Examples of the antiseptic / antifungal agent include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like. It is done.

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 adjusting agent include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide and quaternary ammonium hydroxide. And quaternary phosphonium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate.

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

  Examples of the antioxidant include phenol-based antioxidants (including hindered phenol-based antioxidants), amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

  Examples of the phenolic antioxidant (including hindered phenolic antioxidant) 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) Examples include benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane.

  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) propio Nate] methane, 1,1,3-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, and 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, and trinonylphenyl phosphite.

  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 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 ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), 2,2′-thiobis. (4-tert-octylferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octylferrate) triethanolamine nickel (II) and the like.

The physical properties of the recording ink of the present invention are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the solid content, viscosity, surface tension, pH and the like are preferably in the following ranges.
The solid content in the recording ink is preferably 5 to 20% by mass, more preferably 6 to 15% by mass. If the solid content is less than 5% by mass, a sufficient image density may not be obtained after printing.
Here, the solid content in the ink in the present invention mainly means a water-insoluble colorant and resin fine particles.
The viscosity is preferably 6 to 20 mPa · s, and more preferably 6.5 to 12 mPa · s at 25 ° C. If the initial viscosity is within this range, there will be no significant difference in the viscosity increase. If the viscosity exceeds 20 mPa · s, it may be difficult to ensure ejection stability. If the initial viscosity is within this range, there is no significant difference in the degree of thickening.
The surface tension is preferably 25 to 55 mN / m at 20 ° C. If the surface tension is less than 25 mN / m, bleeding on the recording medium becomes remarkable and stable jetting may not be obtained. If the surface tension exceeds 55 mN / m, ink penetration into the recording medium is sufficient. However, the drying time may be prolonged.
As said pH, 7-10 are preferable, for example.

  Changes in physical properties are observed when ink is stored for a long time. In particular, when heated and stored, the viscosity of the ink increases and the pH decreases, but it is preferable that the change be as small as possible. For example, the rate of thickening after storage at 60 ° C. for 2 weeks is preferably within 5%, and the rate of decrease in pH is preferably within −5%.

  The recording ink of the present invention can be suitably used in various fields, and can be suitably used in an image recording apparatus (printer or the like) based on an ink jet recording method. The recording ink is heated at 50 to 200 ° C. and can be used for a printer or the like having a function of accelerating print fixing. The following ink cartridge, ink recorded matter, ink jet recording apparatus, and ink jet recording method of the present invention It can be particularly preferably used.

(Recording media)
The recording ink of the present invention can form a high-quality image on coated paper having poor water absorbability as well as inkjet exclusive paper and plain paper. Here, the coated paper with poor water absorbability is provided with a coated layer on at least one surface of a support, and to a recording medium for pure water at a contact time of 100 ms measured by a dynamic scanning liquid absorption system. The coated paper for printing whose transfer amount is 3-15 ml / m < ² > is shown.
In the recording medium, the transfer amount of the ink of the present invention to the recording medium at a contact time of 100 ms measured with a dynamic scanning absorption meter is ² to 40 ml / m ² , and 3 to 30 ml / m. ² is preferred. The transfer amount of pure water to the recording medium is preferably ² to 45 ml / m ² , more preferably ³ to 30 ml / m ² .
If the transfer amount of the ink and pure water at the contact time of 100 ms is too small, beading is likely to occur. If it is too large, the ink dot diameter after recording becomes too smaller than the desired diameter. There is.
Transfer amount of said to the recording medium of the ink of the present invention in a dynamic scanning liquid absorption contact time measured by the meter 400ms is ^{3~50ml / m 2, 4~40ml / m} 2 is preferred.
Further, the amount of transferred to the recording medium of the pure water is preferably ^{3~50ml / m 2, 4~40ml / m} 2 is more preferable.
If the amount of transfer at the contact time of 400 ms is too small, the drying property is insufficient, so that spur marks are likely to occur. May become low.

  Here, the dynamic scanning absorptometer (DSA, Papa Technical Journal, Vol. 48, May 1994, pp. 88-92, Shigenori Suga) 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 or ink 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. The measurement was performed at 23 ° C. and 50% RH.

-Support-
The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paper based on wood fibers, and sheet-like materials such as non-woven fabrics mainly composed of wood fibers and synthetic fibers. .

  There is no restriction | limiting in particular as said paper, According to the objective, it can select suitably according to the objective, For example, wood pulp, waste paper pulp, etc. are used. Examples of the wood pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), NBSP, LBSP, GP, and TMP.

  As the raw material of the used paper pulp, the white paper, ruled white, cream white, card, special white, medium white, imitation, fair white, Kent, white, as shown in the used paper standard quality standard table of the used paper recycling promotion center Art, special upper limit, another upper limit, newspaper, magazine, etc. are mentioned. 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 And waste paper, such as 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 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.

  Examples of the internally added sizing agent used for making the support include neutral rosin sizing agents used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resins. System sizing agents and the like. 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.

-Coating layer-
The coating layer contains a pigment and a binder (binder), and further contains a surfactant and other components as necessary.
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 ratio of the particle size is 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 total pigment in the coating layer. 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 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 coating layer. Since the organic pigment is excellent in gloss expression and its specific gravity is smaller than that of an inorganic pigment, it is possible to obtain a 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.

As the binder, an aqueous resin is preferably used.
As the aqueous resin, at least one of a water-soluble resin and a water-dispersible resin is preferably used. There is no restriction | limiting in particular as said water-soluble resin, According to the objective, it can select suitably, For example, modified products of polyvinyl alcohol, such as polyvinyl alcohol, anion modified polyvinyl alcohol, cation modified polyvinyl alcohol, acetal modified polyvinyl alcohol; Polyurethane; polyvinylpyrrolidone and polyvinylpyrrolidone and vinyl acetate copolymer, vinylpyrrolidone and dimethylaminoethyl / methacrylic acid copolymer, quaternized vinylpyrrolidone / dimethylaminoethyl / methacrylic acid copolymer, vinylpyrrolidone and Modified products of polyvinylpyrrolidone such as a copolymer of methacrylamidopropyl trimethylammonium chloride; Cellulo such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose Modified products of cellulose such as cationized hydroxyethyl cellulose; Synthetic resins such as polyester, polyacrylic acid (ester), melamine resin, or modified products thereof, polyester and polyurethane copolymer; poly (meth) acrylic acid, Examples include poly (meth) acrylamide, oxidized starch, phosphate esterified starch, self-modified starch, cationized starch, or various modified starches, polyethylene oxide, sodium polyacrylate, and sodium alginate. These may be used individually by 1 type and may use 2 or more types together.
Among these, from the viewpoint of ink absorbability, polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, a copolymer of polyester and polyurethane, and the like are particularly preferable.

The water-dispersible resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylate ester copolymer Polymer, (meth) acrylic acid ester polymer, vinyl acetate- (meth) acrylic acid (ester) copolymer, styrene-butadiene copolymer, ethylene-propylene copolymer, polyvinyl ether, silicone-acrylic copolymer Coalescence, etc. Further, it may contain a crosslinking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, or may be a copolymer containing units such as N-methylolacrylamide and having a self-crosslinking property. A plurality of these water-based resins can be used simultaneously.
2-100 mass parts is preferable with respect to 100 mass parts of said pigments, and, as for the addition amount of the said aqueous resin, 3-50 mass parts is more preferable. The amount of the aqueous resin added is determined so that the liquid absorption characteristics of the recording medium fall within a desired range.

  When a water-dispersible colorant is used as the colorant, the cationic organic compound is not necessarily added, but is not particularly limited and can be appropriately selected and used depending on the purpose. For example, a primary to tertiary amine, quaternary ammonium salt monomer or oligomer that reacts with a sulfonic acid group, a carboxyl group, an amino group, or the like in a direct dye or acidic dye in water-soluble ink to form an insoluble salt. A polymer etc. are mentioned, Among these, an oligomer or a polymer is preferable.

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.
Among these, low molecular weight cationic organic compounds such as dimethylamine / epichlorohydrin polycondensate and polyallylamine hydrochloride and other relatively high molecular weight cationic organic compounds such as poly (diallyldimethylammonium chloride) It is preferable to use in combination. By using in combination, the image density can be improved and feathering can be further reduced as compared with the case of single use.

The cation equivalent of the cationic organic compound by colloid titration method (using polyvinyl potassium sulfate and toluidine blue) is preferably 3 to 8 meq / g. If the cation equivalent is within this range, good results can be obtained within the dry adhesion range.
Here, in the measurement of the cation equivalent by the colloid titration method, the cationic organic compound is diluted with distilled water to a solid content of 0.1% by mass, and pH adjustment is not performed.
The dry adhesion amount of the cationic organic compound is preferably 0.3 to 2.0 g / m ₂ . If the dry adhesion amount of the cationic organic compound is less than 0.3 g / m ² , sufficient image density improvement and feathering reduction effects may not be obtained.

  There is no restriction | limiting in particular as said surfactant, Although it can select suitably according to the objective, Any of an anionic active agent, a cationic active agent, an amphoteric active agent, and a nonionic active agent can be used. Of these, nonionic active agents are particularly preferred. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and bleeding is improved.

  Examples of the nonionic activator 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 acid amides. 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 and 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. As the ethylene oxide adduct, a product obtained by substituting a part of ethylene oxide with an alkylene oxide such as propylene oxide or 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.

  The addition amount of the surfactant is preferably 0 to 10 parts by mass, and more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of the cationic organic compound.

  Other components can be added to the coating layer as needed, as long as the object and effect of the present invention are not impaired. Examples of the other components include additives such as alumina powder, pH adjuster, preservative, and antioxidant.

  There is no restriction | limiting in particular as a formation method of the said coating layer, According to the objective, it can select suitably, It can carry out by the method of impregnating or apply | coating a coating layer liquid on the said support body. The impregnation or coating method of the coating layer liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, conventional size press, gate roll size press, film transfer size press, blade coater, rod coater It can be applied with various coating machines such as an air knife coater and a curtain coater. Among these, from the viewpoint of cost, a method of impregnating or adhering with a conventional size press, a gate roll size press, a film transfer size press or the like installed in a paper machine and finishing on-machine is preferable.

The adhesion amount of the coating layer liquid is not particularly limited and may be appropriately selected depending on the intended purpose, the solid content is preferably ^{0.5~20g / m 2, 1~15g / m} 2 Gayori preferable. If it is less than 0.5 g / m ² , the ink cannot be sufficiently absorbed, so that the ink overflows and character blurring occurs. On the other hand, if it exceeds 20 g / m ² , the texture of the paper is impaired, resulting in problems such as difficulty in bending and difficulty in writing with a writing instrument.
After the impregnation or coating, drying may be performed as necessary. In this case, the drying temperature is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 100 to 250 ° C. .

  The recording medium may further include a back layer on the back surface of the support, another layer between the support and the coating layer, or another layer between the support and the back layer, and a protective layer on the coating layer. Can also be provided. Each of these layers may be a single layer or a plurality of layers.

  The recording medium of the present invention may be commercially available coated paper for offset printing, coated paper for gravure printing, etc., as long as the liquid absorption property is within the range of the present invention.

The basis weight of the recording medium of the present invention is preferably 50 to 250 g / m ² . If it is less than 50 g / m ² , there is no stiffness, and a conveyance failure such as a recording medium being clogged in the middle of the conveyance path tends to occur. If it exceeds 250 g / m ² , the stiffness becomes too large, so that the recording medium cannot be bent at the curved portion in the middle of the conveyance path, and the conveyance failure such as the recording medium being clogged is likely to occur.

-Ink cartridge-
The ink cartridge of the present invention contains the recording ink 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. What has is mentioned suitably.

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 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 mounted on various ink jet recording apparatuses.
The ink cartridge of the present invention contains the recording ink (ink set) of the present invention and can be used by being detachably attached to various ink jet recording apparatuses, and can be attached to and detached from the ink jet recording apparatus of the present invention described later. It is particularly preferable to install and use it.

-Inkjet recording apparatus and inkjet recording method-
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.
The inkjet recording method of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

-Ink flying process and ink flying means-
The ink flying step is a step of recording an image by applying a stimulus to the recording ink of the present invention and causing the recording ink to fly.
The ink flying means is means for recording an image by applying a stimulus to the recording ink of the present invention and causing the recording ink to fly. The ink flying means is not particularly limited, and 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.

The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned. 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, heat generation, etc. Examples include a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a resistor, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, and an electrostatic actuator that uses an electrostatic force.

  There are no particular restrictions on the manner in which the recording ink flies, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, a recording signal is output to the recording ink in the recording head. Corresponding thermal energy is applied using, for example, a thermal head, bubbles are generated in the recording ink by the thermal energy, and the recording ink is formed into droplets from the nozzle holes of the recording head by the pressure of the bubbles. For example, a discharge injection method may be used. 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 the recording ink is ejected and ejected as droplets from the nozzle holes of the recording head.

  The size of the recording ink droplets to be ejected is preferably 3 to 40 pl, for example, and the ejection jet speed is preferably 5 to 20 m / s, and the driving thereof. The frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

  It is preferable to have a reversing unit that can print on both sides by reversing the recording surface of the recording medium. Examples of the reversing means include a conveyance belt having electrostatic force, a means for holding a recording medium by air suction, and a combination of a conveyance roller and a spur.

It is preferable to have an endless conveying belt and conveying means for conveying the surface of the conveying belt while charging and holding the recording medium. In this case, it is particularly preferable to charge the conveying belt by applying an AC bias of ± 1.2 kV to ± 2.6 kV to the charging roller.
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.

  When an ink having a relatively low surface tension is used like the ink used in the image forming method of the present invention, it is desirable that the nozzle plate is excellent in water repellency and ink repellency. This is because by using a nozzle plate with excellent water repellency and ink repellency, an ink meniscus can be formed normally even with low surface tension ink, and as a result, ink droplet formation (particle formation) can be improved. is there. When the meniscus is formed normally, the ink is not pulled in one direction when the ink is ejected, and as a result, there is little ink ejection bending and an image with high dot position accuracy can be obtained.

In addition, when printing on a medium having low absorbability such as a medium (paper) used in the ink media set of the present invention, the quality of the dot position is remarkably increased in image quality. In other words, since it is difficult for ink to spread on a medium with low absorbency, if the dot position accuracy is as low as possible, a portion where the ink cannot be filled with the medium, that is, a white portion is generated. This portion that cannot be filled up leads to uneven image density and reduced image density, and appears in the degradation of image quality.
However, since the ink-jet head used in the present invention has high dot position accuracy even when using low surface tension ink, the ink can fill the medium even when using low-absorbency media. A printed matter with high image quality can be obtained without deteriorating.

  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 has an apparatus main body (101), a paper feed tray (102) for loading paper mounted on the apparatus main body (101), and an image mounted on the apparatus main body (101). A paper discharge tray (103) for stocking the formed paper and an ink cartridge loading section (104) are provided. On the upper surface of the ink cartridge loading section (104), an operation section (105) such as operation keys and a display is arranged. The ink cartridge loading section (104) has an openable / closable front cover (115) for attaching and detaching the ink cartridge (200).

  As shown in FIGS. 4 and 5, a guide rod (131), which is a guide member horizontally mounted on left and right side plates (not shown), and a stay (132) are provided in the apparatus main body (101). 133) is slidably held in the main scanning direction, and is moved and scanned in the direction of the arrow in FIG. 5 by a main scanning motor (not shown).

The carriage (133) includes a recording head (134) including four inkjet recording heads that eject recording 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 discharge direction is directed downward.
As an inkjet recording head constituting the recording head (134), a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a temperature change A shape memory alloy actuator using a metal phase change, an electrostatic actuator using an electrostatic force, or the like provided as an energy generating means for discharging recording ink can be used.
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 the recording ink of the present invention from the ink cartridge (200) of the present invention loaded in the ink cartridge loading section (104) via a recording ink supply tube (not shown). Is done.

  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 feed tray (102), 1 sheet (142) is fed from the paper stacking unit (141). A half-moon roller (sheet feeding roller 143) that separates and feeds the sheets one by one and a separation pad (144) made of a material having a large friction coefficient are provided opposite to the sheet feeding roller (143). The roller (143) is urged.

  A conveying belt (151) for electrostatically adsorbing and conveying the paper (142) as a conveying unit for conveying the paper (142) fed from the paper feeding unit below the recording head (134). A counter roller (152) for conveying the paper (142) sent from the paper supply unit via the guide (145) between the conveying belt (151) and a paper (substantially vertically upward) ( 142) and a leading guide roller 153 urged toward the conveying belt (151) by the holding member (154). (155) and a charging roller (156) which is a charging means for charging the surface of the conveyor belt (151).

  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 adsorbing 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), It has the same material as the surface layer and a back layer (medium resistance layer, earth layer) that has been subjected to resistance control by carbon. On the back side of the conveyance belt (151), a guide member (161) is arranged corresponding to the printing area by the recording head (134). 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 transport belt (151), and paper discharge A roller (172) and a paper discharge roller (173) are provided, and a paper discharge tray (103) is arranged below the paper discharge roller (172).

  A double-sided paper feeding unit (181) is detachably attached to 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 double-sided paper feed unit (181).

Upon receiving a recording end signal or a signal that the rear end of the paper (142) has reached the recording area, the recording operation is finished and the paper (142) is discharged to the paper discharge tray (103).
When the recording ink remaining amount near end in the sub tank (135) is detected, a required amount of recording ink is supplied from the ink cartridge (200) to the sub tank (135).

  In this ink jet recording apparatus, when the recording ink in the ink cartridge (200) of the present invention is used up, the casing of the ink cartridge (200) can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge (200) can supply recording ink stably even when the ink cartridge (200) is vertically placed and has a front loading configuration. Therefore, even when the upper part of the apparatus main body (101) is closed and installed, for example, even when it is stored in a rack or an object is placed on the upper surface of the apparatus main body (101), the ink The cartridge (200) can be easily replaced.

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.
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.

Next, the ink jet head will be described.
FIG. 6 is an enlarged view of elements of an ink jet head to which the present invention is applied, 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 has an ink supply port (not shown) (supplying ink from the front surface direction to the back direction (back surface direction of the paper) in FIG. 6) and a frame (engraved to form a common liquid chamber (12) ( 10), a fluid resistance portion (21), a flow path plate (20) in which a carving to be a pressurized liquid chamber (22) and a communication port (23) communicating with the nozzle (31) are formed, and a nozzle (31) A nozzle plate (30) to be formed, a diaphragm (60) having a convex part (61), a diaphragm part (62) and an ink inlet (63), and an adhesive layer (70) on the diaphragm (60) A laminated piezoelectric element (50) joined and a base (40) fixing the laminated piezoelectric element (50) 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) includes a lead zirconate titanate (PZT) piezoelectric layer (51) having a thickness of 10 to 50 μm / layer and a silver / palladium (AgPd) layer having a thickness of several μm / layer. Electrode layers (52) are alternately stacked. The internal electrode layer (52) is connected to the external electrode (53) at both ends.
The laminated piezoelectric element (50) is divided on comb teeth by half-cut dicing, and is used as a drive unit (56) and a support unit (57) (non-drive unit) one by one (FIG. 7).
The outer end of one of the two external electrodes (53) (connected to one end of the internal electrode layer (52) in the front or back direction (back side of the paper) in the figure) is divided by half-cut dicing. Further, the length is limited by processing such as notches, and these become a plurality of individual electrodes (54). The other is conductive without being divided by dicing, and becomes a common electrode (55).
An FPC (80) is soldered to the individual electrode (54) of the drive unit. Further, the common electrode (55) 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 (80). A driver IC (not shown) is mounted on the FPC (80), thereby controlling application of drive voltage to the drive unit (56).

The diaphragm (60) is an island-shaped convex portion (island) that joins the thin film diaphragm portion (62) and the laminated piezoelectric element (50) that becomes the drive portion (56) formed in the central portion of the diaphragm portion (62). Part) (61), a thick film part including a beam joined to a support part (not shown), and an opening to be an ink inflow port (63) are formed by stacking two 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 (61) of the diaphragm (60) and the movable part (56) of the laminated piezoelectric element (50), and the connection between the diaphragm (60) and the frame (10) are bonded layers including a gap material ( 70) is bonded by patterning.

The flow path plate (20) uses a silicon single crystal substrate, is engraved to be a fluid resistance portion (21), a pressurized liquid chamber (22), and a through-hole to be a communication port (23) at a position relative to the nozzle (31). Was patterned by an etching method.
The portion left by etching becomes the partition wall (24) of the pressurized liquid chamber (22). Further, in this head, a portion for narrowing the etching width was provided, and this was used as the fluid resistance portion (21).

The nozzle plate (30) is formed of a metal material, for example, an Ni plating film by an electroforming method, and has a large number of nozzles (31) which are fine discharge ports for causing ink droplets to fly. The inner shape (inner shape) of the nozzle (31) is formed in a horn shape (may be a substantially cylindrical shape or a substantially frustum shape). The diameter of the nozzle (31) is about 20 to 35 μm as the diameter on the ink droplet outlet side. The nozzle pitch of each row was 150 dpi.
The ink discharge surface (nozzle surface side) of the nozzle plate (30) is provided with an ink repellent layer (90). Ink, such as PTFE-Ni eutectoid plating, electrodeposition coating of fluororesin, vapor-deposited fluororesin (for example, fluorinated pitch, etc.), baking after solvent application of silicone resin and fluororesin A water-repellent film selected according to the physical properties is provided to stabilize the ink droplet shape and flight characteristics so as to obtain high-quality image quality.

<Ink repellent layer>
-Surface roughness-
The surface roughness Ra of the ink repellent layer used in the present invention is preferably 0.2 μm or less. By setting the surface roughness Ra to 0.2 μm or less, it is possible to reduce wiping residue during wiping.
8 and 9 are sectional views of an ink jet head nozzle plate prepared according to the present invention.
In the embodiment of the present invention, the nozzle plate (2) which is the base material of the inkjet head is produced by electroforming Ni, and the ink repellent film (1) which is a silicone resin film having a thickness of 0.1 μm or more is formed on the surface thereof. The surface roughness is preferably Ra = 0.2 or less. The film thickness of the ink repellent film (1) is more preferably 0.5 μm or more.
When the ink (3) is filled, a meniscus (liquid level) P is formed at the boundary between the ink repellent film (1) and the nozzle plate (2) formed of a silicone resin film, as shown in FIG. 9 (c).

-Round shape-
The cross-sectional area in the plane perpendicular to the center line of the ink repellent film formed on the surface of the ink jet head on which the ink discharge opening is formed is gradually increased as the distance from the substrate surface increases. It is formed to grow.
The shape of the ink repellent film in the vicinity of the opening is preferably a curved surface.
It is preferable that the radius of curvature of the curve in the vicinity of the opening of the ink repellent film in the cross section on the plane including the center line of the opening is greater than or equal to the thickness of the ink repellent film.
The curve in the vicinity of the opening from the edge of the opening of the ink repellent film in a cross section in a plane including the center line of the opening described above forms a substantially arc curve, and the radius of curvature of the arc is the thickness of the ink repellent film. The above is preferable.
It is preferable that a tangent line passing through the edge of the opening of the ink repellent film in a cross section in a plane including the center line of the opening described above has an angle of less than 90 degrees from the surface of the nozzle member including the end.

The opening of the nozzle plate (2) is opened such that a cross section taken along a plane perpendicular to the center line indicated by the alternate long and short dash line in FIG. 9 is substantially circular with the center line as the center. In addition, the ink repellent film (1) formed on the ink ejection surface of the nozzle plate (2) gradually increases as the cross-sectional area of the opening portion by a plane perpendicular to the center line moves away from the nozzle plate (2). It is formed as follows.
More specifically, as shown in FIG. 9A, the opening of the ink repellent film (1) has a round shape in which the curve from the edge of the opening of the nozzle plate (2) to the vicinity of the opening has a radius of curvature r. It has become. The radius of curvature r is preferably equal to or greater than the thickness d other than the vicinity of the opening of the ink repellent film (1).
This thickness d is a thickness in a portion other than the round portion which is an opening portion of the ink repellent film (1), and may preferably be the maximum thickness of the ink repellent film.

  In this way, the opening of the ink repellent film (1) connected to the opening of the nozzle plate (2) has a shape without a sharp point (smooth curve without a pointed portion) and a curve without a catching portion. Therefore, even when wiping with a wiper made of a material such as rubber, the pointed portion is caught by the wiper and the ink repellent film (1) is peeled off from the nozzle plate (2). You can be out of there.

Further, as shown in FIG. 9B, the tangent line passing through the edge of the opening portion of the ink repellent film (1) in the cross section in the plane including the center line of the opening portion of the nozzle plate (2) is the opening portion. The angle θ from the surface of the nozzle plate (2) including the edge of the opening of the nozzle plate (2) connected to the edge is preferably less than 90 degrees.
As described above, since the angle θ between the tangent at the edge of the opening portion of the ink repellent film (1) and the nozzle plate surface (2) is less than 90 degrees, as shown in FIG. The possibility that the meniscus (liquid level) P is stably formed at the boundary portion between the film (1) and the nozzle plate (2) and the meniscus P is formed at other portions can be greatly reduced.
As a result, the meniscus formation surface can be stabilized, so that the ink ejection stability when forming an image in the image forming apparatus using the ink jet head including the nozzle plate (2) is improved. be able to.

As the silicone resin used in the embodiment of the present invention, a room temperature curable liquid silicone resin is desirable, and a silicone resin with a hydrolysis reaction is particularly preferable. In Examples described later, SR2411 manufactured by Toray Dow Corning Co., Ltd. was used.
The following table shows the shape of the ink repellent film (1) in the ink jet head in the present embodiment from the opening edge of the nozzle plate (2) to the vicinity of the opening edge, the ink pool around the nozzle, the edge peeling, It is the result evaluated regarding injection stability.

In the case where the edge portion (near the edge of the opening portion) of the ink-repellent film (1) includes a substantially sharp end, an ink pool is seen around the nozzle, and the edge is peeled off by wiping.
In any of the round shapes, no ink pool occurred, but as a comparative example r <d as illustrated in FIG. 10A, some edges were peeled off, and FIG. In the case of θ> 90 degrees as exemplified in FIG. 5, the ejection of droplets was unstable.
That is, as shown in FIG. 10C, when r <d or θ> 90 degrees, the boundary portion between the ink repellent film (1) and the nozzle plate (2) is filled with the ink (3). When the meniscus (liquid level) P is formed on the ink repellent film (1 ′), the meniscus is formed on the convex portion toward the center of the opening in the ink repellent film (1 ′) Q may be formed. For this reason, variations have occurred in the ejection stability of ink when an image is formed by an image forming apparatus using an ink jet head including such a nozzle plate (2).

Next, the manufacturing method of the nozzle member of the inkjet head according to the above-described embodiment will be described.
FIG. 11 is a diagram showing a configuration in which an ink repellent film (1) is formed by applying a silicone resin by application using the dispenser (4) according to the present embodiment.
A dispenser (4) for applying a silicone solution is disposed on the ink ejection surface side of the nozzle (2) by Ni electroforming, and a predetermined distance between the nozzle plate (2) and the tip of the needle (5) is predetermined. As shown in FIGS. 8 and 9, the ink is discharged from the nozzle plate (2) by scanning the dispenser (4) while discharging silicone from the tip of the needle (5). A silicone resin film could be selectively formed on the surface.

  As the silicone resin used in the present embodiment, a room temperature curing type silicone resin SR2411 (manufactured by Toray Dow Corning Co., Ltd.) viscosity: 10 mPa · s was used. However, a slight amount of silicone was found around the nozzle holes and the back of the nozzle plate. The silicone resin film thus selectively formed had a thickness of 1.2 μm and a surface roughness (Ra) of 0.18 μm.

As shown in FIG. 12A, the application port at the tip of the needle (5) according to the present embodiment has a width that is equal to the application width to the nozzle plate (2) that is the application target. Thereby, the application | coating to the whole coating object can be completed only by scanning a dispenser (4) once in an application direction.
That is, the scanning direction for the coating operation can be set to only one direction, and the necessity of changing the direction as shown in FIG. 12B or scanning in the opposite direction can be eliminated.
Here, as shown in FIG. 12B, the tip of the general needle (5) is much narrower than the application width to the nozzle plate (2) that is the application target, and thus the application to the entire application target is completed. In order to achieve this, it is necessary to change the scanning direction for the coating operation by 90 degrees and move it in the opposite direction, or to scan in multiple directions, and it is difficult to apply a uniform thickness to the entire coating target. Met.
According to the present embodiment, the width of the application port at the tip of the needle (5) is ensured only by the application width to the nozzle plate (2) that is the application target, so that the thickness to be applied over the entire application target is uniform. The surface finish can be made with high accuracy.

FIG. 13 is a diagram illustrating a coating operation using the dispenser (4) according to the present embodiment. The basic configuration is the same as in FIG. 11 described above, but silicone is applied while jetting gas (6) from the nozzle hole (opening) of the nozzle plate (2). As the gas (6), various gases may be used as long as they do not easily cause a chemical reaction with the silicone to be applied. For example, air may be used.
Thus, a silicone resin film can be formed only on the nozzle surface excluding the nozzle holes of the nozzle plate (2) by performing the coating while jetting the gas (6) from the nozzle holes.

Moreover, when it apply | coats using the same silicone resin without injecting gas (6) as mentioned above, and a silicone resin approachs to the predetermined depth, when gas (6) is injected from a nozzle (2), As shown in FIG. 14, an ink repellent layer of silicone resin can be formed to a desired depth (for example, about several μm) of the nozzle inner wall.
That is, in addition to the ink repellent film (1) on the ink ejection surface described above, a very thin ink repellent film (1a) from the edge of the opening of the nozzle plate (2) to a predetermined depth (ink repellent on the inner wall of the opening) Film) can be formed.

  Wiping was performed on the ink-repellent film (1) of the nozzle plate thus prepared using EPDM rubber (rubber hardness 50 degrees). As a result, the ink repellent film (1) of the nozzle plate was able to maintain good ink repellency even after 1000 times of wiping. Further, the nozzle member on which the ink repellent film was formed was immersed in ink at 70 ° C. for 14 days. As a result, it was possible to maintain the ink repellency unchanged from the initial stage.

-Water repellent layer thickness-
FIG. 15 is a view showing an embodiment of the ink jet head of the present invention, and shows a state in which nozzle holes are formed by excimer laser processing. The nozzle plate (43) is obtained by joining a resin member (121) and a high-rigidity member (125) with a thermoplastic adhesive (126). The surface of the resin member (121) is made of SiO ₂ thin film layer (122) and fluorine. A water-repellent layer (123) is sequentially laminated, a nozzle hole (44) having a required diameter is formed in the resin member (121), and the high-rigidity member (125) communicates with the nozzle hole (44). A nozzle communication port (127) is formed. The SiO ₂ thin film layer (122) is formed by a method that allows film formation at a temperature that is relatively not heated, that is, does not cause thermal influence on the resin member. Specifically, it can be said that sputtering, ion beam deposition, ion plating, CVD (chemical vapor deposition), P-CVD (plasma vapor deposition) and the like are suitable.

It is advantageous from the viewpoint of process time and material cost that the SiO ₂ thin film layer (122) has a necessary minimum thickness as long as the adhesion can be secured. This is because if the film thickness is too large, it may interfere with nozzle hole processing with an excimer laser. That is, even if the resin member (121) is cleanly processed into a nozzle hole shape, a part of the SiO ₂ thin film layer (122) may not be sufficiently processed and may remain as a processing residue. Therefore, specifically, it can be said that the range of the film thickness of 1A to 300A is suitable as the range in which the adhesion can be secured and the SiO ₂ thin film layer (122) does not remain at the time of excimer laser processing. More preferably, the range of 10A to 100A is suitable. As a result of the experiment, even when the SiO ₂ film thickness was 30 A, the adhesion was sufficient, and there was no problem with the workability by the excimer laser. In addition, a slight machining residue was observed at 300A, but it was within the usable range. When the current exceeded 300A, a considerably large machining residue was generated, and a nozzle profile that was unusable was observed.

Any material that repels ink can be used as the material of the ink repellent layer, and specific examples include a fluorine-based water repellent material and a silicone-based water repellent material.
Various materials are known as fluorine-based water repellent materials. Here, a mixture of perfluoropolyoxetane and modified perfluoropolyoxetane (manufactured by Daikin Industries, trade name: OPTOOL DSX) with a thickness of 1A to 30A is used. The necessary water repellency is obtained by vapor deposition. As a result of the experiment, there was no difference in the water repellency and wiping durability performance regardless of whether the thickness of OPTOOL DSX was 10A, 20A, or 30A. Therefore, 1A to 20A is more preferable in consideration of cost and the like. Further, an adhesive tape (124) obtained by applying an adhesive material to a resin film is attached to the surface of the fluorine-based water repellent layer (123), and serves as an auxiliary function during excimer laser processing.
Silicone water repellent materials can also be used.
Silicone water repellent materials include room temperature curable liquid silicone resins or elastomers that are applied to the surface of a substrate and polymerized and cured by leaving it in the air at room temperature to form an ink repellent film. Is preferred.

The above-mentioned silicone-based water repellent material is a heat-curable liquid silicone resin or elastomer, and may be applied to the surface of the substrate and cured by heat treatment to form an ink-repellent film.
The silicone-based water repellent material is an ultraviolet curable liquid silicone resin or elastomer, and may be applied to the surface of the substrate and cured by irradiation with ultraviolet rays to form an ink repellent film.
The viscosity of the silicone-based water repellent material is preferably 1000 cp (centipoise) or less.

  FIG. 16 is a diagram showing the configuration of an excimer laser processing machine used when processing the nozzle hole. The excimer laser beam (82) emitted from the laser oscillator (81) is mirrors (83), (85), Reflected by (88) and guided to the processing table (90). A beam expander (84), a mask (86), a field lens (87), and an optical path until the laser beam (82) reaches the processing table (90) so that an optimal beam reaches the workpiece. An imaging optical system (89) is provided at a predetermined position. The workpiece (nozzle plate) (91) is placed on the machining table (90) and receives a laser beam. The processing table (90) is composed of a well-known XYZ table or the like, and can move the workpiece (91) as necessary to irradiate a desired position with a laser beam. Here, the laser is described using an excimer laser, but various lasers can be used as long as they are short wavelength ultraviolet lasers that can be ablated.

FIG. 17 is a diagram schematically showing a nozzle plate manufacturing process in the method for manufacturing an inkjet head of the present invention, and FIG. 17 (A) shows a material that becomes a base material of a nozzle forming member. For example, a film without particles of Kapton (trade name), which is a Dupont polyimide film, is used as the resin film (121). In general polyimide films, particles such as SiO ₂ (silica) are added to the film material from the viewpoint of handling (sliding) in a roll film handling apparatus. However, when nozzle holes are machined with an excimer laser, SiO ₂ (silica) particles have poor processability with the excimer laser, and nozzle irregularities occur. Therefore, the material of the present invention uses a film to which no SiO ₂ (silica) particles are added.

FIG. 17B shows a step of forming a SiO ₂ thin film layer (122) on the surface of the resin film (121), and this SiO ₂ thin film layer (122) is formed in a vacuum chamber. The film thickness is about several A to 200 A, and here, it is formed to a thickness of 10 to 50 A. Here, as a method of sputtering, after sputtering the Si, adhesion using the method of forming the SiO ₂ film by applying the _{O 2} ions in Si surface, the resin film of the SiO ₂ film (121) As a result, it was found that a uniform and dense film was obtained, which was more effective in improving the wiping durability of the water-repellent film.

FIG. 17C is a step of applying a fluorine-based water repellent (123a). As a coating method, a spin coater, roll coater, screen printing, spray coater, or the like can be used. It has been confirmed that the film forming method is more effective because it leads to improving the adhesion of the water-repellent film. Further, it was also found that the vacuum deposition can be further improved by carrying out as it is in a vacuum chamber after forming the SiO ₂ thin film layer (122) in FIG. 17B. That is, conventionally, since the work is once taken out from the vacuum chamber after forming the SiO ₂ thin film layer (122), it is considered that the adhesion is impaired by the adhesion of impurities or the like to the surface. Various materials are known for the fluorine-based water repellent material. Here, perfluoropolyoxetane or modified perfluoropolyoxetane or a mixture of both is used as the amorphous fluorine compound. Necessary water repellency was obtained. The aforementioned “Optool DSX” manufactured by Daikin Industries is sometimes referred to as “alkoxysilane-terminated modified perfluoropolyether”.

FIG. 17D shows an air leaving step after water-repellent film deposition, whereby the fluorine-based water repellent (123a) and the SiO ₂ thin film layer (122) are chemically bonded through the moisture in the air. To become a fluorine-based water repellent layer (123).

  FIG. 17E is a process of applying the adhesive tape (124), and the adhesive tape (124) is applied to the surface to which the fluorine-based water repellent layer (123) is applied. When this adhesive tape (124) is applied, it is necessary to apply it so that no bubbles are generated. This is because if there are bubbles, the nozzle holes opened at the positions where the bubbles are present may be of poor quality due to deposits during processing.

  FIG. 17F shows a nozzle hole (44) processing step, in which the nozzle hole (44) is formed by irradiating an excimer laser from the polyimide film (121) side. After the processing of the nozzle hole (44), the adhesive tape (124) is peeled off and used. Here, the description of the high-rigidity member (125) used for increasing the rigidity of the nozzle plate (43) described in FIG. 15 is omitted, but if applied to this process, the process shown in FIG. It is appropriate to carry out during the step of FIG.

FIG. 18 is a diagram showing an outline of an apparatus used when an inkjet head is manufactured by the inkjet head manufacturing method according to the present invention. It is a process that is called a "process", and is used for the production of antireflection and antifouling films for displays and the like. As shown in the figure, the Si sputter (202), the O ₂ ion gun (203), the Nb sputter (204), and the optool vapor deposition (205), which are stations, are arranged at four locations around the drum (201), and the whole is vacuumed. In a pullable chamber. First, sputtering of Si by Si sputtering (202), then, _{O 2} by ion gun (203) and SiO ₂ against the _{O 2} ions to Si. Thereafter, Nb and Optool DSX are appropriately deposited by Nb sputtering (204) and Optool vapor deposition (205). In the case of an antireflection film, Nb and SiO ₂ are deposited after a necessary number of layers are stacked with a predetermined thickness. In the case of the present invention, since the function of the antireflection film is not necessary, Nb is not necessary, and SiO ₂ and OPTOOL DSX may be provided one by one. By using this apparatus, as described above, after forming the SiO ₂ thin layer (122), it is possible to perform vacuum deposition of the OPTOOL DSX in the vacuum chamber as it is.

-Critical surface tension-
The critical surface tension of the ink repellent layer is preferably 5 to 40 mN / m. Furthermore, it is more preferable that it is 5-30 mN / m. If it exceeds 40 mN / m, a phenomenon in which the nozzle plate is excessively wet from the initial stage occurs, so that the ink discharge curve or abnormal particle generation occurs from the initial stage. Further, if it exceeds 30 mN / m, a phenomenon that the ink becomes too wet with respect to the nozzle plate occurs in long-term use. Therefore, repeated printing may cause ink ejection bending or abnormal particle formation.

A nozzle plate with an ink repellent layer was prepared by applying the ink repellent material described in Table 3 onto an aluminum substrate and drying by heating. When the critical surface tension of the ink repellent layer was measured, it was as shown in Table 3.
The critical surface tension can be determined by the Zisman method. That is, when a liquid with a known surface tension is placed on the ink repellent layer, the contact angle θ is measured, and the surface tension of the liquid is plotted on the x axis and COS θ is plotted on the y axis, a straight line with a downward slope is obtained. (Zisman Plot) The surface tension when this straight line becomes Y = 1 (θ = 0) can be calculated as the critical surface tension γc. As other methods, the critical surface tension can be obtained by using the Fowkes method, the Owens and Wendt method, and the Van Oss method.

In FIG. 6, the frame (10) for forming the engraving that becomes the ink supply port and the common liquid chamber (12) 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 (56) according to the recording signal, thereby causing displacement in the stacking direction in the driving unit (56). The pressurized liquid chamber (22) is pressurized through the nozzle plate (30) to increase the pressure, and ink droplets are ejected from the nozzle (31).
Thereafter, the ink pressure in the pressurized liquid chamber (22) decreases with the end of ink droplet ejection, and negative pressure is generated in the pressurized liquid chamber (22) due to the inertia of the ink flow and the discharge process of the drive pulse. Then, the process proceeds to the ink filling process. At this time, the ink supplied from the ink tank flows into the common liquid chamber (12), passes from the common liquid chamber (12) through the ink inflow port (63), passes through the fluid resistance portion (21), and reaches the pressurized liquid chamber ( 22) is filled.
The fluid resistance portion (21) is effective in the attenuation of the residual pressure vibration after discharge, but becomes resistant to the refilling due to the 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.

(Ink record)
The ink recorded matter recorded by the ink jet recording apparatus and the ink jet recording method of the present invention is the ink recorded matter of the present invention. The ink recorded matter of the present invention has an image formed on the recording medium using the recording ink of the present invention.
There is no restriction | limiting in particular as said recording medium, According to the objective, it can select suitably, For example, a plain paper, glossy paper, special paper, cloth, a film, an OHP sheet etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
The recorded matter has high image quality, no bleeding, excellent temporal stability, and can be suitably used for various purposes as a material on which various prints or images are recorded.

Preparation Example 1 (Surface-treated carbon black pigment dispersion)
1 mol / l sodium persulfate was added to 100 g of carbon (# 960 / Mitsubishi Chemical) having a primary particle size of 16 nm, a specific surface area of 260 m ² / g, and a DBP oil absorption of 69 ml / 100 g, and the mixture was oxidized at 80 ° C. for 10 hours. Processing was performed. Next, after washing with pure water and drying, it was dispersed again in water, neutralized with sodium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.35 mS / cm, and the volume average particle size was 123 nm.

Preparation Example 2 (Surface-treated carbon black pigment dispersion)
1 mol / l sodium hypochlorite was added to 100 g of carbon (# 960 / Mitsubishi Chemical) having a primary particle size of 16 nm, a specific surface area of 260 m ² / g, and a DBP oil absorption of 69 ml / 100 g, and stirred at 80 ° C. for 10 hours. Then, oxidation treatment was performed. Next, after washing with pure water and drying, it was again dispersed in water, neutralized with potassium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.3 mS / cm, and the volume average particle size was 128 nm.

Preparation Example 3 (Surface-treated carbon black dispersion)
After adding 3 L of pure water to 100 g of carbon (# 960 / Mitsubishi Chemical) having a primary particle size of 16 nm, a specific surface area of 260 m ² / g, and a DBP oil absorption of 69 ml / 100 g, the mixture was stirred for 5 minutes and then injected with ozone gas for 1 hour to oxidize Processing was performed. Next, after washing with pure water and drying, it was again dispersed in water, neutralized with sodium hydroxide so that the pH was 7, and the residual salt was separated by ultrafiltration. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.25 mS / cm, and the volume average particle diameter was 132 nm.

Preparation Example 4 (Surface-treated carbon black dispersion)
1 mol / l sodium hypochlorite was added to 100 g of carbon (# 960 / Mitsubishi Chemical) having a primary particle size of 16 nm, a specific surface area of 260 m ² / g, and a DBP oil absorption of 69 ml / 100 g, and stirred at 100 ° C. for 15 hours. Then, oxidation treatment was performed. Next, after washing with pure water and drying, it was again dispersed in water, neutralized with potassium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.38 mS / cm, and the volume average particle size was 126 nm.

Preparation Example 5 (surface-treated carbon black dispersion)
1 mol / l sodium persulfate was added to 100 g of carbon (# 7550 / Tokai carbon) having a primary particle size of 21 nm, a specific surface area of 135 m ² / g, and a DBP oil absorption of 53 ml / 100 g, and the mixture was oxidized at 80 ° C. for 10 hours. Processing was performed. Next, after washing with pure water and drying, it was dispersed again in water, neutralized with sodium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.2 mS / cm, and the volume average particle diameter was 61 nm.

Preparation Example 6 (Surface-treated carbon black dispersion)
1 mol / l sodium persulfate was added to 100 g of carbon (MA8 / Mitsubishi Chemical) with a primary particle size of 24 nm, specific surface area of 120 m ² / g, and DBP oil absorption of 57 ml / 100 g, followed by oxidation treatment at 80 ° C. for 10 hours. Was done. Next, after washing with pure water and drying, it was dispersed again in water, neutralized with sodium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.23 mS / cm, and the volume average particle size was 55 nm.

Preparation Example 7 (Surface-treated carbon black dispersion)
1 mol / l sodium persulfate was added to 100 g of carbon (MA600 / Mitsubishi Chemical) having a primary particle size of 20 nm, a specific surface area of 140 m ² / g, and a DBP oil absorption of 131 ml / 100 g, followed by oxidation at 80 ° C. for 10 hours. Was done. Next, after washing with pure water and drying, it was dispersed again in water, neutralized with sodium hydroxide so that the pH was 7, and the residual salt was separated with an ultrafiltration membrane. Moisture was adjusted so that the pigment concentration was 20%, and filtered through a 0.8 μ membrane filter to remove coarse particles.
The conductivity of the obtained dispersion was 1.35 mS / cm, and the volume average particle size was 205 nm.

Example 1
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 1 9.0% by mass (as solid content)
・ 1,5-pentanediol 22.5% by mass
・ Glycerin 7.5% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 60.0% by mass

Example 2
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 2 8.0% by mass (as solid content)
・ Acrylic resin fine particles 5.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
-0.1 mass% pH buffer of chemical formula (4)
・ Ion-exchanged water 57.9% by mass

Example 3
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of adjustment example 5 8.0% by mass (as solid content)
・ Acrylic resin fine particles 5.0% by mass (as solid content)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
-PH buffering agent of chemical formula (8) 0.1% by mass
・ Ion-exchanged water 57.9% by mass

Example 4
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of adjustment example 6 8.0% by mass (as solid content)
・ Acrylic resin fine particles 5.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 58.0% by mass

Example 5
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of adjustment example 7 8.0 mass% (as solid content)
・ Acrylic resin fine particles 5.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 58.0% by mass

Example 6
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 1 14.0% by mass (as solid content)
・ Acrylic resin fine particles 2.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 55.0% by mass

Example 7
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 4.0% by mass (as solid content)
・ Acrylic resin fine particles 2.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 1,6-hexanediol 24.0% by mass
・ Glycerin 8.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 61.0% by mass

Example 8
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 1 7.0% by mass (as solid content)
・ Acrylic resin fine particles 4.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
-Surfactant of structural formula (I) (m = 2, n = 10) 1.0 mass%
・ Ion-exchanged water 61.0% by mass

Example 9
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 1 16.0% by mass (as solid content)
・ 1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 55.0% by mass

Example 10
An ink composition having the following formulation was prepared and adjusted with sodium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of Preparation Example 1 7.0% by mass (as solid content)
・ Acrylic resin fine particles 4.0% by mass (as solid content)
(Aqua Brid 4720 / Daicel Chemical Industries, Ltd.)
・ 1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion exchange water

Comparative Example 1
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of adjustment example 3 6.0% by mass (as solid content)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 63.0% by mass

Comparative Example 2
An ink composition having the following formulation was prepared and adjusted with triethanolamine so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and produced the ink.
<Ink composition>
-Carbon black dispersion of adjustment example 4 8.0% by mass (as solid content)
・ 3-methyl-1,3-butanediol 21.0% by mass
・ Glycerin 7.0% by mass
・ Surfactant 1.0% by mass
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ Ion-exchanged water 62.0% by mass

Comparative Example 3
・ Carbon black A (# 47, manufactured by Mitsubishi Chemical) 15wt%
・ Johncrill 68 (Johnson Polymer) 5wt%
・ Glycerin 10wt%
・ Ion exchange water 70wt%
The above material was dispersed with glass beads in a sand mill for 3 hours, and then filtered through a 5 μ membrane filter to obtain a carbon black dispersion A. Using this dispersion, an ink composition having the following formulation was prepared and adjusted with triethanolamine so as to have a pH of 9. Thereafter, filtration was performed with a 0.8 μm membrane filter to prepare an ink.
Carbon dispersion A 7.0 wt% (as solid content)
・ 1,3-butanediol 22.5 wt%
・ Glycerin 7.5wt%
・ Surfactant 1.0wt%
(Softanol EP7025, manufactured by Nippon Shokubai Co., Ltd.)
・ 2,2,4-trimethyl-1,3-pentanediol 2.0wt%
・ Ion-exchanged water 67wt%

Various characteristics of the obtained recording ink were evaluated as follows. Each prescription and result are shown in Tables 4-5.
<Volume average particle diameter of ink>
The recording ink was diluted with pure water, and the volume average particle size (D50%) was measured using a particle size distribution measuring device (Microtrac UPA, Nikkiso Co., Ltd.).

<Ink viscosity>
The viscosity at 25 ° C. was measured using RL-500 (Toki Sangyo Co., Ltd.).

<Ink surface tension>
The surface tension at 23 ° C. ± 2 ° C. was measured using a static surface tension meter (BVP-Z, Kyowa Interface Chemical Co., Ltd.).

<Ink pH>
The pH at 23 ° C. ± 2 ° C. was measured using a pH meter (HM-A, Toa Denpa Kogyo Co., Ltd.).

<Image density>
3 to 7 were filled with the recording inks of Examples 1 to 10 and Comparative Examples 1 to 3, respectively, and printed on Type 6200 paper (manufactured by NBS Ricoh Co., Ltd.) at a resolution of 600 dpi. After drying, the image density was measured using a reflection color spectrocolorimetric densitometer (manufactured by X-Rite).

<Fixability>
3 to 7 were filled with the recording inks of Examples 1 to 10 and Comparative Examples 1 to 3, respectively, and printed on Type 6200 paper (manufactured by NBS Ricoh Co., Ltd.) at a resolution of 600 dpi. After drying, the printed portion was rubbed 10 times with a cotton cloth, and the pigment transfer condition to the cotton cloth was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
○: Pigment transfer to cotton fabric is hardly seen Δ: Some pigment transfer is seen ×: Pigment is clearly transferred

<Continuous discharge property>
The ink jet printers shown in FIGS. 3 to 7 are filled with the recording inks of Examples 1 to 10 and Comparative Examples 1 to 3, respectively, and 200 sheets are continuously printed on Type 6200 paper (manufactured by NBS Ricoh Co., Ltd.) at a resolution of 600 dpi. The discharge disturbance and discharge failure were evaluated according to the following criteria.
〔Evaluation criteria〕
○: Discharge turbulence or non-discharge is not observed.

<Discharge after leaving>
The ink jet printers shown in FIGS. 3 to 7 were filled with the recording inks of Examples 1 to 10 and Comparative Examples 1 to 3, respectively, and after cleaning all the colors, they were left in an environment of 32 ° C. and 30% for one month. did. Nozzle check printing was performed after standing, and ejection disturbance and ejection failure were evaluated according to the following criteria.
〔Evaluation criteria〕
○: Discharge turbulence or non-discharge is not observed.

<Ink storage stability>
The recording inks of Examples 1 to 10 and Comparative Examples 1 to 3 were filled in a cartridge and stored at 60 ° C. for 2 weeks, and the viscosity increase rate and pH change of the ink were observed.
The ink thickening rate was (ink thickening rate%) = {(viscosity after storage) − (viscosity before storage)} / (viscosity before storage) × 100.

<Printability on coated paper for printing>
The ink jet printers shown in FIGS. 3 to 7 were filled with the recording inks of Examples 1 to 12 and Comparative Examples 1 to 3, respectively, and printing was performed on α mat paper (Hokuetsu Paper) at 600 dpi. The color unevenness of the part was evaluated according to the following criteria.
In addition, the transfer amount of pure water to the recording medium at a contact time of 100 ms measured with a dynamic scanning absorption meter (DSA, Kyowa Success Co., Ltd.) of α mat paper was 3.6 ml / m ² .
[Character bleeding evaluation criteria]
○: Very clear characters without blurring Δ: Some blurring is observed and the sharpness is slightly inferior ×: There is remarkable blurring and there is no sharpness [Evaluation criteria for solid color unevenness]
○: A clear image with almost no color unevenness Δ: Some color unevenness is seen and the sharpness is slightly inferior ×: Significant color unevenness is seen and there is no clearness

<Humic acid concentration>
The recording inks of Examples 1 to 10 and Comparative Examples 1 to 3 were first subjected to column chromatography to separate additives such as surfactants, rust inhibitors, and UV absorbers, and carbon black was recovered. It vacuum-dried with the dryer of 50 degreeC, and after water and a solvent were fully evaporated, it diluted so that it might become 20 wt% with water. 50 g of this diluted solution was taken in a beaker and passed through an ultrafiltration membrane (Pellicon Biomax 50 manufactured by MILLIPORE) for 30 minutes to obtain a brown liquid. This liquid was diluted 10 times with ion-exchanged water and measured at a wavelength of 230 to 260 nm with a spectrophotometer (U-3310 manufactured by Hitachi High-Tech) using a quartz cell (optical path length 10 mm), and the maximum absorbance obtained. Was multiplied by 10 to obtain the humic acid concentration.

<Alkali metal concentration>
The recording inks of Examples 1 to 10 and Comparative Examples 1 to 3 were diluted 10 times with ion-exchanged water, and sodium contained in the ink using a high frequency induction plasma emission analyzer (ICP-1000IV manufactured by Shimadzu Corporation). The concentration of potassium was measured, and the obtained value was multiplied by 10 to obtain the total value as the alkali metal concentration.

<Increase rate of ink viscosity accompanying water evaporation>
The inks of Examples 1, 5, 7, 9 and Comparative Examples 1 to 3 were allowed to stand in an environment of 50 ° C. and 10%, and the ink mass change after standing for a certain time and the viscosity at 25 ° C. were measured. The amount of water evaporation and the increase in viscosity relative to the initial viscosity were determined by the following formula.
(Moisture evaporation amount [%]) = {(initial ink mass) − (ink mass after water evaporation)} / (initial ink mass) × 100
・ (Thickening with respect to initial viscosity) = (Ink viscosity after water evaporation) / (Initial viscosity)
FIG. 19 shows the relationship between the water evaporation (%) and the ink viscosity (mPa · s).
Table 6 shows the thickening relative to the initial viscosity when the water evaporation rate is 35 to 40%.

Example 11
Next, as described above, the present invention includes a recording method in which recording is performed on a recording medium (recording medium) with a specific amount of ink transfer using the above-described ink. Next, the recording method will be described in detail. I will explain it.

(Production Example 1)
-Production of support-
A 0.3 mass% slurry having the following composition was made with a long paper machine to prepare a support 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.
-Hardwood bleached kraft pulp (LBKP): 80 parts by mass-Softwood bleached kraft pulp (NBKP): 20 parts by mass-Light calcium carbonate (trade name: TP-121, manufactured by Okutama Kogyo Co., Ltd.) ... 10 Part by mass-Aluminum sulfate-1.0 part by weight-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

(Production Example 2)
-Production of recording medium 1-
70 parts by mass of clay having a particle diameter of 2 μm or less as a pigment of 97% by mass, 30 parts by mass of heavy calcium carbonate having an average particle diameter of 1.1 μm, and styrene having a glass transition temperature (Tg) of −5 ° C. as an adhesive -Add 8 parts by weight of butadiene 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 obtain a coating solution having a solid content concentration of 60% by weight. Prepared.
The obtained coating solution is applied to both sides using a blade coater so that the solid content per side is 8 g / m ² on the above-prepared support, dried with hot air, and then subjected to super calender treatment. “Recording medium 1” was produced.

(Production Example 3)
-Production of recording medium 2-
70 parts by mass of clay having a particle diameter of 2 μm or less as a pigment of 97% by mass, 30 parts by mass of heavy calcium carbonate having an average particle diameter of 1.1 μm, and styrene having a glass transition temperature (Tg) of −5 ° C. as an adhesive -Addition of 7 parts by mass of butadiene copolymer emulsion, 0.7 parts by mass of phosphoric acid esterified starch, 0.5 parts by mass of calcium stearate as an auxiliary agent, and further water to add a coating solution having a solid content concentration of 60% by mass Was prepared.
The obtained coating solution was coated on both sides using a blade coater so that the solid content per side was 8 g / m ² on the prepared support, dried with hot air, and then subjected to supercalender treatment. “Recording medium 2” was produced.

-Recording media 3-
Coated paper for gravure printing (trade name; space DX, basis weight = 56 g / m ² , manufactured by Nippon Paper Industries Co., Ltd. was used.

-Recording media 4-
Coated paper for offset (trade name; aurora coat, basis weight = 104.7 g / m ² , Nippon Paper Industries Co., Ltd.) was used.

-Recording media 5-
Ink-jet mat-coated paper (trade name; Superfine exclusive paper, manufactured by Seiko Epson Corporation) was used.

<Measurement of ink transfer by dynamic scanning absorption meter>
About the recording medium 1, the transfer amount of each recording ink of Examples 1-10 and Comparative Examples 1-3 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 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 the environmental conditions of 23 ° C. and 50% RH.
Next, for the recording media 1 to 5, the amount of ink transferred in Example 3 and Example 5 was measured by a dynamic scanning absorption meter as follows.
Further, beading, character bleeding, drying property, and OD value of images printed on the respective recording media were evaluated.

<Beading>
For the recording media 1 to 5, the inks of Examples 3 and 5 were printed at a resolution of 600 dpi, and beading and drying properties were visually evaluated.
〔Evaluation criteria〕
Rank 4: There is no occurrence of beading and uniform printing.
Rank 3: Slight beading is observed.
Rank 2: Obviously beading is observed.
Rank 1: Significant beading is observed.

<Text blur>
For the recording media 1 to 5, the inks of Examples 3 and 5 were printed at a resolution of 600 dpi, and the beading was visually evaluated.
〔Evaluation criteria〕
Rank 4: Visible printing with no occurrence of bleeding.
Rank 3: The occurrence of faint bleeding is recognized.
Rank 2: The occurrence of bleeding is clearly observed.
Rank 1: Significant beading is observed.

<Drying>
For the recording media 1 to 5, the inks of Examples 3 and 5 were printed at a resolution of 600 dpi. Immediately after the end of printing, plain paper (Type 6200 / manufactured by NBS Ricoh) was placed on the printing part and pressed with a finger, and the degree of transfer to plain paper was visually evaluated.
〔Evaluation criteria〕
Rank 4: Transcription is not recognized.
Rank 3: Faint transfer is recognized.
Rank 2: Transcription is clearly recognized.
Rank 1: Remarkable transfer is recognized.

<Image density>
For the recording media 1 to 5, the inks of Examples 3 and 5 were printed at a resolution of 600 dpi. The image density of the solid print portion was measured using a reflection type colorimetric densitometer X-Rite 938. The results are shown in Tables 7 and 8.

It is the schematic which shows an example of the ink cartridge of this invention. FIG. 2 is a schematic view including a case (exterior) of the ink cartridge of FIG. 1. FIG. 4 is a perspective explanatory view showing a state where an ink cartridge loading unit cover of the ink jet recording apparatus is opened. It is a schematic block diagram explaining the whole structure of an inkjet recording device. It is a schematic enlarged view which shows an example of the inkjet head of this invention. It is an element enlarged view showing an example of an ink jet head of the present invention. It is a principal part expanded sectional view of the direction between channels of an example of the inkjet head of this invention. It is sectional drawing of the inkjet head nozzle plate produced by this invention. It is sectional drawing of the inkjet head nozzle plate produced by this invention. It is sectional drawing of the inkjet head nozzle plate produced as a comparative example. It is a figure which shows the application | coating operation | movement using the dispenser which concerns on this invention. It is a figure which shows the application port of a needle front-end | tip. It is a figure which shows the application | coating operation | movement using the dispenser which concerns on this invention. It is a figure which shows the ink-repellent layer of a silicone resin. It is the figure which showed one Example of the inkjet head of this invention. It is the figure which showed the structure of the excimer laser processing machine. It is the figure which showed the nozzle plate manufacturing process typically. It is a figure which shows the outline | summary of the apparatus used when manufacturing an inkjet head. It is a figure which shows the relationship between a water evaporation amount and ink viscosity.

Explanation of symbols

(About Figures 1 and 2)
200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge exterior (case)
(About FIGS. 3-5)
101 apparatus main body 102 paper feed tray 103 paper discharge tray 104 ink cartridge loading unit 105 operation unit 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 143 paper supply roller 144 Separator Pad 145 Guide 151 Conveyor Belt 152 Counter Roller 153 Conveyor Guide 154 Pressing Member 155 Tip Pressure Roller 156 Charging Roller 157 Conveying Roller 158 Densation Roller 161 Guide Member 171 Separating Claw 172 Discharge Roller 173 Unit 182 Manual paper feed unit (About Figs. 6 and 7)
DESCRIPTION OF SYMBOLS 10 Frame 12 Common liquid chamber 20 Flow path plate 21 Fluid resistance part 22 Pressurized liquid chamber 23 Communication port 24 Partition 30 Nozzle plate 31 Nozzle 40 Base 50 Multilayer piezoelectric element 51 Piezoelectric layer 52 Internal electrode layer 53 External electrode 54 Individual electrode 55 Common Electrode 56 Drive part (movable part)
57 Supporting part 60 Diaphragm 61 Island-like convex part 62 Diaphragm part 63 Ink inlet 70 Adhesive layer 80 FPC
90 Ink-repellent layer (for FIGS. 8 to 14)
DESCRIPTION OF SYMBOLS 1 Ink repellent film 1 'Ink repellent film 1a Ink repellent film 2 Nozzle plate 3 Ink 4 Dispenser 5 Needle 6 Gas (About FIG. 15, 17)
43 Nozzle plate 44 Nozzle hole 121 Resin member 122 SiO ₂ thin film layer 123 Fluorine-based water repellent layer 123a Fluorine-based water repellent agent 124 Adhesive tape 125 High-rigidity member 126 Thermoplastic adhesive 127 Nozzle communication port (FIG. 16)
81 Laser oscillator 82 Excimer laser beam 83 Mirror 84 Beam expander 85 Mirror 86 Mask 87 Field lens 88 Mirror 89 Imaging optical system 90 Processing table 91 Workpiece (nozzle plate)
(About FIG. 18)
201 Drum 202 Si Sputter 203 O ₂ Ion Gun 204 Nb Sputter 205 Op Tool Deposition

Claims (21)

It contains at least water, a water-soluble organic solvent, a surfactant, and carbon black having a hydrophilic group on the surface, and the detected amount of humic acid eluted in a 20 Wt% dispersion of the carbon black has a wavelength of 230 to 260 nm. maximum absorbance 5.0-20.0 der in is, recording ink alkali metal content in the ink is characterized in der Rukoto than 1500ppm or less 100ppm tHAT measured. The recording ink according to claim 1, wherein the carbon black is contained in an amount of 5 to 15% by mass. 3. The recording method according to claim 1, wherein when the water evaporation rate with respect to the total ink weight is 35 to 40 wt%, the degree of increase with respect to the initial viscosity is 5.0 times or more and does not exceed 550 times. ink. The recording ink according to any one of claims 1 to 3, further comprising a pH buffer. The recording ink according to any one of claims 1 to 4, wherein the pH buffer is an organic pH buffer selected from Good buffers. 6. The recording ink according to claim 1, wherein the carbon black having a hydrophilic group has a volume average particle diameter of 60 to 200 nm when dispersed in water. The recording ink according to claim 1, comprising resin fine particles having a volume average particle diameter of 50 to 200 nm. 8. The recording ink according to claim 1, wherein at least a part of the hydrophilic group terminal of the carbon black is substituted with an alkali metal. The recording ink according to any one of claims 1 to 8 viscosity at 25 ° C. of the recording ink is characterized in that it is a 6~20mPa · s. An inkjet recording method for performing recording by using the ink according to any one of claims 1 to 9, the ink-repellent layer is formed on the surface where the ink ejection opening of the recording head is formed A characteristic recording method. The recording method according to claim 10 , wherein the ink repellent layer is made of a fluorine material or a silicone material. The recording method according to claim 10 , wherein a surface roughness Ra of the ink repellent layer is 0.2 μm or less. Claim 10 wherein the cross-sectional area of the opening near a plane perpendicular to the center line of the opening of the ink repellent layer, characterized in that formed as will become sequentially larger with distance from the substrate surface The recording method described in 1. The recording method according to claim 10 , wherein a critical surface tension γc of the ink repellent layer is 5 to 40 mN / m. By using the ink according to any one of claims 1 to 9, a recording method, which comprises recording on a recording medium (recording medium) having a coating layer on at least one surface of a support and the support . The ink according to any one of claims 1 to 9, the amount of transferred onto the recording medium of the ink at a contact time 100ms measured by a dynamic scanning absorptometer at 23 ° C. 50% RH is 2~40ml / ^{m 2} And a transfer amount of the ink to the recording medium at a contact time of 400 ms is 3 to 50 ml / m ² . The recording medium is composed of at least a substrate and a coating layer, according to claim 15 or 16 solid adhering amount of coating coating layer is characterized by a 0.5~20.0g / m ² The recording method described in 1. The recording method according to any one of claims 15 to 17 wherein the recording medium is, the basis weight is characterized by a 50 to 250 g / ^{m 2.} A stimulus to the recording ink according to any one of claims 1 to 9 is applied, at least an ink jetting unit for recording an image by ejecting the recording ink, the stimulation is, heat (temperature), pressure An ink jet recording apparatus characterized by being at least one selected from vibration and light. An ink jet recording apparatus which comprises using a recording method according to any one of claims 10 to 18. A method for evaluating a recording ink comprising at least water, a water-soluble organic solvent, a surfactant, and carbon black having a hydrophilic group on the surface, wherein humic acid eluted in a 20 Wt% dispersion of the carbon black Depending on whether the detected amount is 5.0 to 20.0 in terms of the maximum absorbance measured at a wavelength of 230 to 260 nm and the amount of alkali metal contained in the ink is 100 ppm or more and 1500 ppm or less, the coating with poor water absorption is used. A method for evaluating a recording ink, comprising evaluating whether a high-quality image can be formed even on a working paper.

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