JP2013159644A - Inkjet ink and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inkjet ink excellent in image density on plain paper, preservation stability, ejection stability and adhesion resistance, and to provide an ink cartridge, in which the inkjet ink is housed, and an inkjet recording apparatus using the inkjet ink.SOLUTION: This inkjet ink contains: oxidized carbon black that is ozone-oxidized; a compound shown by chemical formula: CHOCHCHCON(CH); and water. The oxidized carbon black has 10-20% of volatile portions and 90-150 m/g of BET specific surface area.

Description

  The present invention relates to an inkjet ink, a method for manufacturing an inkjet ink, an ink cartridge, and an inkjet recording apparatus.

  An ink jet recording apparatus ejects a small amount of ink with pressure generated using bubbles, piezo, electrostatic, etc. generated by heat, adheres to a recording medium such as paper, and then dries the image. It is an apparatus to form.

  In recent years, the demand for industrial use has increased, and it is desired to increase the speed and support various recording media. With the increase in speed, an ink jet printer equipped with a line head is also required.

  In addition, from the viewpoint of environment and safety, there is a high demand for water-based inkjet ink.

  Furthermore, in order to achieve high image quality and high speed, the nozzle tends to be reduced in diameter.

  However, inkjet inks containing pigments are liable to agglomerate solids with the evaporation of moisture, and it is desired to ensure ejection stability.

Patent Document 1 discloses an aqueous ink composition comprising a pigment, water, an organic solvent, a resin, and a surface tension adjusting agent for an ink composition. At this time, the organic solvent has the general formula R ¹ OCH ₂ CH ₂ CONR ² R ^3.
(In the formula, R ¹ is an alkyl group having 1 to 8 carbon atoms, and R ² and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. It is a group having an ether bond in it)
The content of the organic solvent is 10 to 49% by mass of the total amount of water and the organic solvent.

  However, there is a problem that the image density, storage stability, ejection stability, and sticking resistance for plain paper cannot be achieved at the same time.

  In view of the above-described problems of the prior art, the present invention provides an inkjet ink excellent in image density, storage stability, ejection stability and anti-sticking property on plain paper, an ink cartridge containing the inkjet ink, and the inkjet ink. An object of the present invention is to provide an ink jet recording apparatus to be used.

The inkjet ink of the present invention is an oxidized carbon black that has been oxidized by ozone, chemical formula CH ₃ OCH ₂ CH ₂ CON (CH ₃ ) ₂
The oxidized carbon black has a volatile content of 10% or more and 20% or less, and a BET specific surface area of 90 m ² / g or more and 150 m ² / g or less.

The method for producing an inkjet ink of the present invention comprises a step of producing oxidized carbon black by ozone oxidation of carbon black, and the oxidized carbon black and chemical formula CH ₃ OCH ₂ CH ₂ CON (CH ₃ ) _2.
The oxidized carbon black has a volatile content of 10% to 20% and a BET specific surface area of 90 m ² / g to 150 m ² / g. It is.

  The ink cartridge of the present invention contains the inkjet ink of the present invention.

  The ink jet recording apparatus of the present invention has a discharge means for discharging the ink jet ink of the present invention.

  According to the present invention, there are provided an inkjet ink excellent in image density, storage stability, ejection stability and anti-sticking property with respect to plain paper, an ink cartridge containing the inkjet ink, and an inkjet recording apparatus using the inkjet ink. be able to.

It is a perspective view which shows an example of the inkjet recording device of this invention. It is the schematic which shows the whole structure of the inkjet recording device of FIG. FIG. 2 is a schematic diagram illustrating the ink cartridge of FIG. 1.

  Next, the form for implementing this invention is demonstrated with drawing.

The ink-jet ink of the present invention has a chemical formula CH ₃ OCH ₂ CH ₂ CON (CH ₃ ) ₂ as an oxidized carbon black that has been oxidized with ozone and a wetting agent.
(3-methoxy-N, N-dimethylpropionamide) and water.

  If the inkjet ink does not contain ozone-oxidized carbon black, the image density, storage stability, ejection stability, and sticking resistance to plain paper will be reduced. Further, when the inkjet ink does not contain 3-methoxy-N, N-dimethylpropionamide, storage stability, ejection stability, sticking resistance and drying property are lowered.

  The volatile content of oxidized carbon black is 10 to 20%, preferably 12 to 18%. When the volatile content of the oxidized carbon black is less than 10% or more than 20%, the storage stability, ejection stability, and sticking resistance are lowered.

  The volatile content of oxidized carbon black can be measured using the measurement method described in DIN 53552.

BET specific surface area of the oxidized carbon black is ^{90~150m 2 / g, 100~140m 2 /} g are preferred. When the BET specific surface area of the oxidized carbon black is less than 90 m ² / g or more than 150 m ² / g, the storage stability, ejection stability and anti-sticking property are lowered.

  The BET specific surface area of oxidized carbon black can be measured using the measurement method described in DIN 66132.

The oxidized carbon black is obtained by ozone-oxidizing carbon black having a BET specific surface area of 90 to 150 m ² / g and adjusting the volatile content to 10 to 20%.

  A method for ozone-oxidizing carbon black is not particularly limited, and examples thereof include a method of circulating ozone through carbon black.

  The volatile content of the oxidized carbon black can be increased by increasing the circulation amount of ozone or extending the circulation time of ozone.

  The carbon black to be ozone-oxidized preferably has an oil absorption of 230 g / 100 or more in terms of image density.

  The oil absorption of carbon black can be measured using the DIN ISO 787/5 method.

  The carbon black to be oxidized with ozone is not particularly limited, and examples thereof include furnace black, lamp black, acetylene black, and gas black. Of these, gas black is preferable in terms of image density.

  The carbon black to be oxidized with ozone preferably has an average primary particle size of 13 to 30 nm.

  The oxidized carbon black is preferably neutralized with a base. Thereby, storage stability and discharge stability can be further improved.

  The base is not particularly limited, but alcohol amines such as diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol; alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide Ammonium hydroxide such as ammonium hydroxide and quaternary ammonium hydroxide; phosphonium hydroxide such as quaternary phosphonium hydroxide; carbonates of alkali metals such as lithium carbonate, sodium carbonate and potassium carbonate Etc. Among these, alkali metal hydroxides are preferable and potassium hydroxide is more preferable in terms of image density with respect to plain paper.

  The alkali metal ions generated by neutralizing oxidized carbon black with an alkali metal hydroxide can be analyzed using ICP emission spectroscopic analysis, ion chromatography, or the like.

  When the oxidized carbon black is neutralized with a base, 10 to 25% by mass of oxidized carbon black is dispersed in water and then neutralized with a base to adjust the pH to 6 to 8. .

  The content of 3-methoxy-N, N-dimethylpropionamide in the inkjet ink of the present invention is usually 1 to 50% by mass, preferably 2 to 40% by mass, and more preferably 5 to 30% by mass. When the content of 3-methoxy-N, N-dimethylpropionamide in the inkjet ink of the present invention is less than 1% by mass, the ejection stability and the sticking resistance may be lowered, and when it exceeds 50% by mass. In addition, the ejection stability and the drying property may be deteriorated.

  The inkjet ink of the present invention may further contain a wetting agent other than 3-methoxy-N, N-dimethylpropionamide.

  The wetting agent other than 3-methoxy-N, N-dimethylpropionamide is not particularly limited, but glycerin, diethylene glycol, 1,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, propylene Glycol, dipropylene glycol, trimethylol propane, trimethylol ethane, ethylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol Polyhydric alcohols such as 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol; ethylene glycol monoethyl ether Polyhydric alcohol alkyl ethers such as ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, etc. A polyhydric alcohol aryl ether of 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, etc. Ring compounds; Amides such as formamide, N-methylformamide, N, N-dimethylformamide; Monoethanolamide Emissions, diethanolamine, triethanolamine, monoethylamine, diethylamine, amine such as triethylamine; dimethyl sulfoxide, sulfolane, sulfur-containing compounds such as thiodiethanol; propylene carbonate, ethylene and the like carbonate, can be used alone or in combination. Among these, glycerin and / or 1,3-butanediol are preferable in terms of image density and dryness with respect to plain paper.

  As other wetting agents, saccharides and derivatives thereof can be used.

  The saccharides are not particularly limited, but monosaccharides such as glucose, mannose, fructose, ribose, xylose, arabinose, galactose; disaccharides such as maltose, cellobiose, lactose, sucrose, trehalose; oligosaccharides such as maltotriose; α -Polysaccharides such as cyclodextrin and cellulose.

  Examples of the saccharide derivatives include maltitol, sorbite sugar alcohol sugar sugar reducing sugars; aldonic acid, uronic acid sugars; amino acids, thioic acids, and the like.

  The content of oxidized carbon black in the inkjet ink of the present invention is usually 1 to 20% by mass. When the content of oxidized carbon black in the ink-jet ink is less than 1% by mass, the image density may be lowered, and when it exceeds 20% by mass, the ejection stability may be lowered.

  The inkjet ink of the present invention includes oxidized carbon black other than oxidized carbon black that has been oxidized with ozone, carbon black coated with a resin, carbon black that has been grafted, carbon black that has been encapsulated, Carbon black etc. may further be included.

  The average particle diameter of oxidized carbon black in the inkjet ink is usually 90 to 1500 nm.

  In addition, the average particle diameter of the oxidized carbon black in the inkjet ink can be measured using a transmission electron microscope H-7000 (manufactured by Hitachi).

  The method for adjusting the volume average particle size of oxidized carbon black in the inkjet ink is not particularly limited, but a method of preparing an oxidized carbon black dispersion by dispersing oxidized carbon black in water using a disperser, dispersion And a method of dispersing the ink-jet ink using a machine. Among these, a method for producing an oxidized carbon black dispersion is preferable in that it is easy to adjust the volume average particle size of oxidized carbon black in the inkjet ink.

  The disperser is not particularly limited, and examples thereof include a sand mill, a ball mill, a roll mill, a bead mill, a nanomizer, a homogenizer, and an ultrasonic disperser.

  The density | concentration of oxidized carbon black at the time of producing an oxidized carbon black dispersion is 0.1-50 mass% normally, and 0.1-30 mass% is preferable.

  The oxidized carbon black dispersion is obtained by dispersing oxidized carbon black in water, separating coarse particles using a filter, a centrifugal separator, or the like, and deaeration as necessary.

  The inkjet ink of the present invention may further contain a water-dispersible resin, a surfactant, a penetrating agent, a pH adjuster, an antiseptic / antifungal agent, a chelating reagent, a rust inhibitor, an antioxidant, an ultraviolet absorber, and the like. .

  The form of the water-dispersible resin in water is an emulsion, but any of a single-layer structure type emulsion, a core-shell type emulsion, and a power feed type emulsion may be used.

  The water-dispersible resin is not particularly limited, but is a condensation synthetic resin such as polyester, polyurethane, epoxy resin, polyamide, polyether, (meth) acrylic resin, acrylic-silicone resin, fluorine-based resin; polyolefin, polystyrene-based resin And addition synthetic resins such as polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins and unsaturated carboxylic acid resins; and natural polymers such as celluloses, rosins and natural rubbers. You may use together. Among these, a fluorine resin is preferable.

  The surfactant is not particularly limited as long as the leveling property can be improved, and examples thereof include a fluorine-based surfactant and a silicone-based surfactant. Of these, fluorine surfactants are preferred.

  The number of carbon atoms substituted by fluorine in the fluorosurfactant is usually 2 to 16, and 4 to 16 is preferable. If the number of carbon atoms substituted by fluorine in the fluorosurfactant is less than 2, the leveling properties of the inkjet ink may be reduced, and if it exceeds 16, the storage stability of the inkjet ink may be reduced. .

  The fluorosurfactant is not particularly limited, but perfluoroalkyl sulfonic acid compounds such as perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate; perfluoro such as perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylate Perfluoroalkyl phosphate compounds such as perfluoroalkyl phosphate esters and perfluoroalkyl phosphate salts; perfluoroalkyl ethylene oxide adducts; polyoxy having a perfluoroalkyl ether group in the side chain Alkylene ether polymers, sulfates of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in the side chain, polyoxyalkyls having perfluoroalkyl ether groups in the side chain Polyoxyalkylene ether polymer compounds having perfluoroalkyl ether group of salts of emissions ether polymer side chain, and the like. Among these, in terms of foamability, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable.

The counter ion of the anionic fluorosurfactant is not particularly limited, but Li ⁺ , Na ⁺ , K ⁺ , NH ₄ ⁺ , ⁺ NH ₃ CH ₂ CH ₂ OH, ⁺ NH ₂ (CH ₂ CH ₂ OH ) ₂ , ⁺ NH (CH ₂ CH ₂ OH) _{3 and the} like.

  Commercially available fluorosurfactants include Zonyl FS-300 (manufactured by DuPont), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (and above, manufactured by Neos). ), PF-151N (Omnova).

  Although it does not specifically limit as a silicone type surfactant, Side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side chain both terminal modified polydimethylsiloxane, etc. are mentioned.

  Although it does not specifically limit as a modified group of a silicone type surfactant, A polyoxyethylene group, a polyoxyethylene polyoxypropylene group, etc. are mentioned.

  The total content of the fluorine-based surfactant and the silicone-based surfactant in the inkjet ink of the present invention is usually 0.01 to 3.0% by mass, preferably 0.5 to 2% by mass. When the total content of the fluorine-based surfactant and the silicone-based surfactant in the inkjet ink of the present invention is less than 0.01% by mass, the leveling property of the inkjet ink may be deteriorated, and 3.0% by mass. If it exceeds 1, the image density may decrease.

  The penetrant is preferably a polyol having a solubility in water of 20 ° C. of 0.2 to 5.0% by mass.

  Such polyol is not particularly limited, but 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3- Propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1, Examples thereof include aliphatic diols such as 2-diol and 2-ethyl-1,3-hexanediol. Of these, 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol are preferable.

  Other penetrants include, but are not limited to, polyol ethers such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether; ethanol, etc. And lower alcohols.

  The content of the penetrant in the inkjet ink of the present invention is usually 0.1 to 4.0% by mass. When the content of the penetrant in the ink-jet ink of the present invention is less than 0.1% by mass, the quick-drying property of the ink-jet ink may be deteriorated. In addition, the image density may decrease.

  The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 to 11, but alcohol amines such as diethanolamine, triethanolamine, and 2-amino-2-ethyl-1,3-propanediol ; Hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; hydroxides of ammonium such as ammonium hydroxide and quaternary ammonium hydroxide; hydroxides of phosphonium such as quaternary phosphonium hydroxide And alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate.

  The antiseptic / antifungal agent is not particularly limited, and examples thereof include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, and sodium pentachlorophenol.

  Examples of the chelating reagent include, but are not limited to, sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

  The rust inhibitor is not particularly limited, and examples thereof include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  The antioxidant is not particularly limited, but butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-) 6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4 8,10-tetrixaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert -Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ', 5 '-Di-tert-butyl-4'-hydroxyphenyl) propionate] phenolic antioxidants such as methane; phenyl-β-naphthylamine, α-naphthylamine, N, N'-di-sec-butyl-p-phenylenediamine Phenothiazine, N, N′-diphenyl-p-phenylenediamine, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl -Phenol, butylhydroxyanisole, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4 , 4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene-3 (3,5-di-tert-butyl) -4-dihydroxyphenyl) propionate] amine antioxidants such as methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane; dilauryl-3,3'- Thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-β, β′-thiodipropionate, 2-mercaptobenzimidazole, Sulfur-based antioxidants such as dilauryl sulfide; triphenyl phosphite, octadec Phosphite, triisodecyl phosphite, trilauryl trithiophosphite, phosphorus-based antioxidants such as trinonylphenyl phosphite, and the like.

  Although it does not specifically limit as an ultraviolet absorber, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone Benzophenone ultraviolet absorbers such as 2,2 ′, 4,4′-tetrahydroxybenzophenone; 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 Benzotriazole ultraviolet absorbers such as chlorobenzotriazole; phenyl salicylate , Salicylate ultraviolet absorbers such as p-tert-butylphenyl salicylate and p-octylphenyl salicylate; ethyl-2-cyano-3,3′-diphenylacrylate, methyl-2-cyano-3-methyl- Cyanoacrylate ultraviolet absorbers such as 3- (p-methoxyphenyl) acrylate and butyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate; 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-octyl ferrate) triethanolamine nickel (II) And the like of the nickel complex salt ultraviolet absorber.

  The inkjet ink of the present invention comprises a composition containing ozone-oxidized carbon black dispersion, 3-methoxy-N, N-dimethylpropionamide, and water, stirred and mixed using a disperser, and then filtered, centrifuged. It is obtained by filtering coarse particles using a separator or the like and degassing as necessary.

  The disperser is not particularly limited, and examples thereof include a sand mill, a ball mill, a roll mill, a bead mill, a nanomizer, a homogenizer, and an ultrasonic disperser.

  The inkjet ink of the present invention can be applied to inkjet recording apparatuses such as inkjet printers, facsimile apparatuses, copying apparatuses, and printer / fax / copier multifunction machines.

  FIG. 1 shows an example of the ink jet recording apparatus of the present invention.

  The ink jet recording apparatus 100 includes a paper feed tray 101 for loading paper, a paper discharge tray 102 for stocking paper on which an image is formed, and an ink cartridge loading unit 103. On the upper surface of the ink cartridge loading unit 103, an operation unit 104 on which operation keys, a display, and the like are installed is disposed. The ink cartridge loading unit 103 is provided with an openable and closable cover 103 a for attaching and detaching the ink cartridge 200.

  In the inkjet recording apparatus 100, as shown in FIG. 2, a carriage 107 is slidably held in the main scanning direction by a guide rod 105 and a stay 106 that are horizontally mounted on left and right side plates (not shown). It is moved and scanned in the main scanning direction by a main scanning motor (not shown).

  The carriage 107 includes four inkjet heads 108 that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk), and a plurality of ink ejection ports in the main scanning direction. They are arranged in the crossing direction and are mounted so that the direction in which the ink droplets are ejected is downward.

  The inkjet head 108 is not particularly limited, but a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. A shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like can be used.

  Also, the carriage 107 is equipped with sub-tanks 109 for each color for supplying each color ink-jet ink to the ink-jet head 108. The sub tank 109 is supplied with ink-jet ink from an ink cartridge 200 loaded in the ink cartridge loading unit 103 via an ink supply tube (not shown) and is replenished.

  On the other hand, as a paper feeding unit for feeding the paper P stacked on the paper stacking unit (pressure plate) 102a of the paper feeding tray 102, the paper feeding is performed by separating and feeding the paper P one by one from the paper stacking unit 102a. A separation pad 111 made of a material having a large friction coefficient is provided so as to face the roller 110 and the paper feeding roller 110. At this time, the separation pad 111 is biased toward the paper feed roller 110 side.

  A transport belt 113 for electrostatically attracting and transporting the paper P as a transport section for transporting the paper P fed from the paper feed section via the guide 112 on the lower side of the inkjet head 108, and the paper P A counter roller 114 for transporting the paper P sandwiched between the transport belt 113 and a transport guide 115 for changing the direction of the paper P transported substantially vertically upward by approximately 90 ° to follow the transport belt 113. Further, a tip pressurizing roller 117 urged toward the conveying belt 113 by the pressing member 116 is installed. A charging roller 118 for charging the surface of the conveyor belt 113 is provided.

  The conveyance belt 113 is an endless belt, is stretched between the conveyance roller 119 and the tension roller 120, and can circulate in the direction in which the paper P is conveyed. In addition, a guide member 121 is disposed on the back side of the conveyance belt 113 so as to correspond to an image forming area formed by the inkjet head 108.

  The transport belt 113 is not particularly limited, but a surface layer that electrostatically adsorbs the paper P made of a resin such as tetrafluoroethylene and ethylene copolymer (ETFE) having a thickness of about 40 μm, and a resistance by carbon Except for being controlled, those having a back layer (medium resistance layer, earth layer) made of the same material as the surface layer can be used.

  As a paper discharge unit for discharging the paper P on which an image is formed by the inkjet head 108, a separation claw 122 for separating the paper P from the transport belt 113, a paper discharge roller 123, and a paper discharge roller 124 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 123.

  A double-sided paper feeding unit 125 is detachably attached to the back surface of the inkjet recording apparatus 100. The double-sided paper feeding unit 125 takes in and reverses the paper P returned by rotating the transport belt 113 in the direction opposite to the direction in which the paper P is transported, and then between the counter roller 114 and the transport belt 113. Feed paper. A manual paper feed unit 126 is installed on the upper surface of the double-sided paper feed unit 125.

  In the ink jet recording apparatus 100, the paper P is separated and fed one by one from the paper feeding unit, and the paper P fed substantially vertically upward is guided by the guide 112 and between the transport belt 113 and the counter roller 114. It is sandwiched and conveyed. Further, the front end is guided by the transport guide 115 and pressed against the transport belt 113 by the front end pressure roller 117, and the transport direction is changed by about 90 °.

  At this time, since the conveyance belt 113 is charged by the charging roller 118, the paper P is electrostatically attracted to the conveyance belt 113 and conveyed. Therefore, by driving the inkjet head 108 in accordance with the image signal while moving the carriage 107, ink droplets are ejected onto the stopped paper P to form an image for one line, and the paper P is transferred by a predetermined amount. After the conveyance, an image for the next line is formed. Upon receiving a signal indicating completion of image formation or a signal indicating that the trailing edge of the paper P has reached the image forming area, the image forming operation is completed, and the paper P is discharged onto the paper discharge tray 103.

  When the near end of the remaining amount of inkjet ink in the sub tank 109 is detected, a required amount of inkjet ink is supplied from the ink cartridge 200 to the sub tank 109.

  In the ink jet recording apparatus 100, when the ink jet ink in the ink cartridge 200 is used up, the casing of the ink cartridge 200 can be disassembled and the ink bag inside can be replaced. Further, the ink cartridge 200 can stably supply ink-jet ink even when the ink cartridge 200 is placed vertically and has a front loading configuration. Therefore, when the upper side of the ink jet recording apparatus 100 is closed, for example, when it is stored in a rack, or when an object is placed on the upper surface of the ink jet recording apparatus 100. However, the ink cartridge 200 can be easily replaced.

  The example in which the inkjet ink of the present invention is applied to a serial type (shuttle type) inkjet recording apparatus scanned by a carriage has been described above, but the present invention can be similarly applied to a line type inkjet recording apparatus having a line type head. .

  FIG. 3 shows the ink cartridge 200.

  The ink cartridge 200 is used in such a manner that an ink bag 201 filled with inkjet ink is accommodated in a plastic casing 202 and is detachably mounted on the inkjet recording apparatus 100.

  The ink bag 201 is composed of a packaging member such as a non-permeable aluminum laminate film or resin film, and after filling and discharging the ink jet ink from the ink injection port 201a, the ink injection port 201a is fused. It is sealed by. Further, the ink bag 201 is formed with an ink discharge port 201b made of a rubber member. When supplying ink jet ink to the sub tank 109, the ink bag 201 is installed at the tip of the ink supply tube at the ink discharge port 201b. Stab the needle.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited by an Example. In addition, a part is a mass part.

<Example 1>
After putting 200 g of carbon black PRINTEX-U (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was carried out at 5 ° C. for 5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 10% and a BET specific surface area of 110 m ² / g.

  After premixing 25 parts of oxidized carbon black and 70 parts of distilled water, 5 parts of distilled water was further added. Next, using a disk type bead mill KDL type batch type (manufactured by Shinmaru Enterprises Co., Ltd.) and zirconia beads having a diameter of 0.2 mm, oxidized carbon black was applied at a peripheral speed of 8 m / s and a liquid temperature of 10 ° C. for 7 minutes. Dispersed in water. Furthermore, coarse particles were separated using a centrifuge Model-3600 (manufactured by Kubota Corporation) to obtain an oxidized carbon black dispersion. The oxidized carbon black dispersion had a volume average particle size of 115 nm and a standard deviation of 45.3 nm.

  The volume average particle size of the oxidized carbon black dispersion was measured at 22 ° C. using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).

  32 parts of oxidized carbon black dispersion, 25 parts of 3-methoxy-N, N-dimethylpropionamide, 15 parts of 1,3-butanediol and 10 parts of glycerin, 2 parts of 2-ethyl-1,3-hexanediol, solid content Fluorosurfactant Zonyl FS-300 (manufactured by DuPont) having a mass of 40% by mass, a solid content of 50% by mass, an average particle size of 150 nm, and an MFT of 30 ° C. or less of fluoroethylene / vinyl ether alternating copolymer The combined emulsion, Lumiflon FE4300 (Asahi Glass Co., Ltd.) 6.0 parts and distilled water 7.5 parts were mixed with stirring for 30 minutes. Next, after adding a 40 mass% aqueous solution of 2-amino-2-ethyl-1,3-propanediol to adjust the pH to 10, the mixture was stirred and mixed for 30 minutes to obtain an inkjet ink. The volume average particle diameter of carbon black in the inkjet ink was 115.5 nm.

  The average particle size of carbon black in the inkjet ink was measured using a transmission electron microscope H-7000 (manufactured by Hitachi).

<Example 2>
Inkjet ink as in Example 1, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 115.3 nm.

<Example 3>
Inkjet ink as in Example 1 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 115.5 nm.

<Example 4>
Inkjet ink as in Example 1, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 115.2 nm.

<Example 5>
After putting 200 g of carbon black PRINTEX-U (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was performed at 0 ° C. for 10 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 20% and a BET specific surface area of 110 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 107 nm. The oxidized carbon black dispersion had a volume average particle size of 116 nm and a standard deviation of 46.2 nm.

<Example 6>
Inkjet ink as in Example 5, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 116.4 nm.

<Example 7>
Inkjet ink as in Example 5 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 116.2 nm.

<Example 8>
Inkjet ink as in Example 5, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 116.7 nm.

<Example 9>
After putting 200 g of carbon black NIPEX160 (manufactured by Degussa) into a cylindrical ozone treatment device, ozone is generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.) at 30 ° C. Ozone oxidation was performed for 5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 10% and a BET specific surface area of 150 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 121.8 nm. The oxidized carbon black dispersion had a volume average particle size of 121.3 nm and a standard deviation of 52.1 nm.

<Example 10>
Inkjet ink as in Example 9 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 121.7 nm.

<Example 11>
Inkjet ink as in Example 9, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 120.3 nm.

<Example 12>
Inkjet ink as in Example 9, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 121.8 nm.

<Example 13>
After putting 200 g of carbon black NIPEX160 (manufactured by Degussa) into a cylindrical ozone treatment device, ozone is generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.) at 30 ° C. Ozone oxidation was performed for 10 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 20% and a BET specific surface area of 150 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 122.2 nm. The oxidized carbon black dispersion had a volume average particle size of 122.1 nm and a standard deviation of 53.6 nm.

<Example 14>
Inkjet ink as in Example 13 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 122.1 nm.

<Example 15>
Inkjet ink as in Example 13 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 122.8 nm.

<Example 16>
Inkjet ink as in Example 13 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 122.4 nm.

<Example 17>
After putting 200 g of carbon black PRINTEX 140 (manufactured by Degussa) into a cylindrical ozone treatment device, ozone is generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.) at 30 ° C. Ozone oxidation was performed for 5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 10% and a BET specific surface area of 90 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 119.2 nm. The oxidized carbon black dispersion had a volume average particle size of 118.3 nm and a standard deviation of 47.3 nm.

<Example 18>
Inkjet ink as in Example 17, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 119.3 nm.

<Example 19>
Inkjet inks were prepared in the same manner as in Example 17 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 119.1 nm.

<Example 20>
Inkjet ink as in Example 17, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 119.5 nm.

<Example 21>
After putting 200 g of carbon black PRINTEX 140 (manufactured by Degussa) into a cylindrical ozone treatment device, ozone is generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.) at 30 ° C. Ozone oxidation was performed for 10 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 20% and a BET specific surface area of 90 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 120.3 nm. The oxidized carbon black dispersion had a volume average particle size of 119.5 nm and a standard deviation of 47.8 nm.

<Example 22>
Inkjet ink as in Example 21, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 5 parts, 25 parts and 20 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 121.2 nm.

<Example 23>
Inkjet ink as in Example 21, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 45 parts, 0 parts and 5 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 120.4 nm.

<Example 24>
Inkjet inks were prepared in the same manner as in Example 21 except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 50 parts, 0 parts and 0 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 120.3 nm.

<Example 25>
After putting 200 g of carbon black PRINTEX-U (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was carried out at 5 ° C. for 5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 10% and a BET specific surface area of 110 m ² / g.

  After premixing 25 parts of oxidized carbon black and 70 parts of distilled water, neutralize with 20% by mass of 2-amino-2-ethyl-1,3-propanediol and adjust the pH to 7. Distilled water was added so that the total amount was 100 parts. Next, using a disk type bead mill KDL type batch type (manufactured by Shinmaru Enterprises Co., Ltd.) and zirconia beads having a diameter of 0.2 mm, the oxidized carbon black is applied for 5 minutes at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. Dispersed in water. Furthermore, coarse particles were separated using a centrifuge Model-3600 (manufactured by Kubota Corporation) to obtain an oxidized carbon black dispersion. The oxidized carbon black dispersion had a volume average particle size of 140 nm and a standard deviation of 70 nm.

  An inkjet ink was obtained in the same manner as in Example 1 except that the obtained oxidized carbon black dispersion was used. The average particle size of carbon black in the inkjet ink was 141.2 nm.

<Example 26>
Inkjet recording was carried out in the same manner as in Example 25 except that triethanolamine having a solid content of 20% by mass was used instead of 2-amino-2-ethyl-1,3-propanediol having a solid content of 20% by mass. Ink was obtained. The average particle size of carbon black in the inkjet ink was 141.6 nm. The oxidized carbon black dispersion had a volume average particle size of 141.3 nm and a standard deviation of 69.5 nm.

<Example 27>
An inkjet ink was prepared in the same manner as in Example 25 except that a 20% by mass aqueous solution of sodium hydroxide was used instead of 2-amino-2-ethyl-1,3-propanediol having a solid content of 20% by mass. Obtained. The average particle size of carbon black in the inkjet ink was 142.3 nm. The oxidized carbon black dispersion had a volume average particle size of 142.5 nm and a standard deviation of 70.0 nm.

<Example 28>
An inkjet ink was prepared in the same manner as in Example 25 except that a 10% by mass aqueous solution of lithium hydroxide was used instead of 2-amino-2-ethyl-1,3-propanediol having a solid content of 20% by mass. Obtained. The average particle size of carbon black in the inkjet ink was 141.8 nm. The oxidized carbon black dispersion had a volume average particle size of 141.4 nm and a standard deviation of 69.4 nm.

<Example 29>
An inkjet ink was prepared in the same manner as in Example 25 except that a 10% by mass aqueous solution of potassium hydroxide was used instead of 2-amino-2-ethyl-1,3-propanediol having a solid content of 20% by mass. Obtained. The average particle size of carbon black in the inkjet ink was 141.3 nm. The oxidized carbon black dispersion had a volume average particle size of 141.7 nm and a standard deviation of 70.2 nm.

<Comparative Example 1>
Inkjet ink as in Example 1, except that the addition amounts of 3-methoxy-N, N-dimethylpropionamide, 1,3-butanediol and glycerin were changed to 0 part, 20 parts and 30 parts, respectively. Got. The average particle size of carbon black in the inkjet ink was 115.6 nm.

<Comparative example 2>
After putting 200 g of carbon black PRINTEX-U (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Oxidation with ozone at 3.5 ° C. for 3.5 hours gave an oxidized carbon black. The oxidized carbon black had a volatile content of 9% and a BET specific surface area of 110 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 115.3 nm. The oxidized carbon black dispersion had a volume average particle size of 114.8 nm and a standard deviation of 46.2 nm.

<Comparative Example 3>
After putting 200 g of carbon black PRINTEX-U (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was carried out at 12 ° C. for 12 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 21% and a BET specific surface area of 110 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 116.4 nm. The oxidized carbon black dispersion had a volume average particle size of 116.7 nm and a standard deviation of 47.9 nm.

<Comparative example 4>
After putting 200 g of carbon black PRINTEX-35 (manufactured by Degussa) into a cylindrical ozone treatment device, ozone was generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was performed at ℃ for 6.5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 13% and a BET specific surface area of 65 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 116.3 nm. The oxidized carbon black dispersion had a volume average particle size of 115.8 nm and a standard deviation of 47.3 nm.

<Comparative Example 5>
After putting 200 g of carbon black PRINTEX-85 (manufactured by Degussa) into a cylindrical ozone processor, ozone is generated at 6 g / h using an ozone generator KQS-120 (manufactured by Kotohira Kogyo Co., Ltd.), 30 Ozone oxidation was performed at ℃ for 6.5 hours to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 13% and a BET specific surface area of 200 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 117.8 nm. The oxidized carbon black dispersion had a volume average particle size of 117.2 nm and a standard deviation of 48.1 nm.

<Comparative Example 6>
100 g of carbon black PRINTEX-U (manufactured by Degussa) and 500 g of distilled water were mixed with stirring, and 1000 g of 12% by mass sodium hypochlorite was added dropwise, followed by boiling for 6 hours and wet oxidation. Next, after filtering with glass fiber filter paper and washing with distilled water, it was dried using a high-temperature bath at 100 ° C. to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 13% and a BET specific surface area of 110 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 118.2 nm. The oxidized carbon black dispersion had a volume average particle size of 117.2 nm and a standard deviation of 47.9 nm.

<Comparative Example 7>
After stirring and mixing 100 g of carbon black PRINTEX-U (manufactured by Degussa) and 500 g of distilled water, 600 g of 10% by mass sodium peroxodisulfate was added dropwise, followed by boiling for 6 hours and wet oxidation. Next, after filtering with glass fiber filter paper and washing with distilled water, it was dried using a high-temperature bath at 100 ° C. to obtain oxidized carbon black. The oxidized carbon black had a volatile content of 13% and a BET specific surface area of 110 m ² / g.

  An inkjet ink was obtained in the same manner as in Example 4 except that the obtained oxidized carbon black was used. The average particle size of carbon black in the inkjet ink was 117.3 nm. The oxidized carbon black dispersion had a volume average particle size of 116.2 nm and a standard deviation of 48.3 nm.

  Tables 1 and 2 show the characteristics of the ink-jet inks of Examples and Comparative Examples.

次に、実施例及び比較例のインクジェットインクを用いて、画像濃度、保存安定性、吐出安定性、インク固着性及び乾燥性を評価した。

Next, image density, storage stability, ejection stability, ink fixing property, and drying property were evaluated using the ink jet inks of Examples and Comparative Examples.

<Image density>
After the ink cartridge is filled with the ink jet ink, it is mounted on the ink jet printer IPSiO GXe5500 (manufactured by Ricoh), and a solid image is formed on plain paper PPC paper 4024 (manufactured by Xerox) and MC glossy paper (manufactured by EPSON). The image density was measured using a densitometer. In addition, the case where the image density with respect to the plain paper is 1.30 or more, ◎, the case where it is 1.20 or more and less than 1.30, ◯, the case where it is 1.10 or more and less than 1.20, △, 1.00 The case where it was less than 1.10 was determined as Δ, and the case where it was less than 1.00 was determined as ×. Further, the case where the image density on the glossy paper is 1.80 or more, ◎, the case where it is 1.70 or more and less than 1.80, ◯, the case where it is 1.60 or more and less than 1.70, ◯ △, 1.50. The case where it was less than 1.60 was judged as Δ, and the case where it was less than 1.50 was judged as x.

<Storage stability>
Inkjet ink 50g was sealed in a sample bottle SV-50 (manufactured by Nidec Rika), and the viscosity before and after storage at 70 ° C for 4 weeks was measured using a viscometer RE500 (manufactured by Toyo Seiki Co., Ltd.), and the formula Viscosity after storage-viscosity before storage) / (viscosity before storage) x 100
From this, the rate of change in viscosity was calculated, and the storage stability was evaluated. When the rate of change in viscosity is less than 5%, ◎ when 5% or more and less than 10%, ◯ when 10% or more and less than 15%, or △, when 15% or more and less than 20% Was judged as Δ, and the case of 20% or more as x.

<Discharge stability>
After the ink cartridge was filled with the ink jet ink, it was mounted on an ink jet printer IPSiO GXe5500 (manufactured by Ricoh) to form an image. Next, after the ink jet printer is allowed to stand at 50 ° C. for 2.5 months with the ink jet head capped, the number of cleaning operations required to restore the ink jet ink discharge state to the initial discharge state is measured. The ejection stability was evaluated. In addition, the case where the number of cleaning operations is 0: ◎: 1 time: ◯: 2 times: △: 3 times: △: 4 times or more: x Judged.

<Fixing resistance>
After changing the drive voltage of the piezo element so that the ejection amount of the inkjet ink becomes equal using the inkjet printer IPSiO GXe5500 (manufactured by Ricoh) under the environment of 28 ± 0.5 ° C. and 15 ± 5% RH, The operation of performing head cleaning 10 times every hour for 10 hours was performed. Next, after leaving it to stand for 12 hours, the adhesion of the inkjet ink in the wiper portion and wiper cleaner portion of the maintenance device was visually evaluated. In addition, the case where there was no adhesion of inkjet ink was evaluated as ◯, the case where there was a slight adhesion of inkjet ink, Δ, and the case where there was adhesion of inkjet ink as x.

<Drying>
After the ink cartridge was filled with the ink jet ink, it was mounted on an ink jet printer IPSiO GXe5500 (manufactured by Ricoh), and a test chart was formed on MyPaper (manufactured by Ricoh). The filter paper was pressed against the “■” portion of the test chart immediately after formation, and the presence or absence of transfer stain was visually evaluated. In addition, the case where there was no transfer dirt was evaluated as ◯, the case where there was a slight transfer dirt, and the case where there was transfer dirt as x.

  Table 3 shows the evaluation results of the image density, storage stability, ejection stability, ink fixing property, and drying property of the inkjet inks of Examples and Comparative Examples.

表１〜３から、実施例１〜２９のインクジェットインクは、普通紙及び光沢紙に対する画像濃度、保存安定性、吐出安定性、耐固着性及び乾燥性に優れることがわかる。

From Tables 1 to 3, it can be seen that the inkjet inks of Examples 1 to 29 are excellent in image density, storage stability, ejection stability, sticking resistance and drying property with respect to plain paper and glossy paper.

  On the other hand, since the inkjet ink of Comparative Example 1 does not contain 3-methoxy-N, N-dimethylpropionamide, storage stability, ejection stability, adhesion resistance, and drying properties are reduced.

  In the inkjet ink of Comparative Example 2, since the volatile content of oxidized carbon black is 9%, the image density, storage stability, ejection stability, and sticking resistance to glossy paper are reduced.

  In the inkjet ink of Comparative Example 3, since the volatile content of oxidized carbon black is 21%, the image density, storage stability, ejection stability, and sticking resistance to glossy paper are reduced.

In the inkjet ink of Comparative Example 4, since the oxidized carbon black has a BET specific surface area of 65 m ² / g, the image density, storage stability, ejection stability, and sticking resistance to glossy paper are reduced.

In the inkjet ink of Comparative Example 5, since the oxidized carbon black has a BET specific surface area of 200 m ² / g, the image density, storage stability, ejection stability, and sticking resistance to glossy paper are reduced.

  In the inkjet inks of Comparative Examples 6 and 7, since the oxidized carbon black is not ozone-oxidized, the image density, storage stability, ejection stability, and sticking resistance with respect to plain paper and glossy paper are lowered.

DESCRIPTION OF SYMBOLS 100 Inkjet recording apparatus 108 Inkjet head 200 Ink cartridge

JP 2011-68838 A

Claims (5)

Oxidized carbon black oxidized by ozone, chemical formula CH ₃ OCH ₂ CH ₂ CON (CH ₃ ) ₂
And a compound represented by
The inkjet carbon black has an volatile content of 10% to 20% and a BET specific surface area of 90 m ² / g to 150 m ² / g.   The inkjet ink according to claim 1, wherein the oxidized carbon black is neutralized with an alkali metal hydroxide. A process of producing oxidized carbon black by ozone oxidation of carbon black;
The oxidized carbon black and the chemical formula CH ₃ OCH ₂ CH ₂ CON (CH ₃ ) ₂
Having a step of dispersing a composition containing the compound represented by:
The oxidized carbon black has a volatile content of 10% or more and 20%, and a BET specific surface area of 90 m ² / g or more and 150 m ² / g or less.   An ink cartridge containing the ink-jet ink according to claim 1.   An ink jet recording apparatus comprising: an ejection unit that ejects the ink jet ink according to claim 1.

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