JP6891983B2 - Inkjet recording device, inkjet recording method - Google Patents

Description

The present invention relates to an inkjet recording device and an inkjet recording method using the same.

Inkjet printers are widely used in general households as digital signal output devices because they have advantages such as low noise, low running cost, and easy color printing.
In recent years, inkjet technology has been used not only for home use but also for industrial applications such as displays, posters, and bulletin boards.
On the other hand, as inks for inkjet recording in industrial applications, solvent-based inkjet inks containing a resin in which an organic solvent is used as a vehicle and dissolved in the organic solvent, and ultraviolet curable inkjet inks containing a polymerizable monomer as a main component have been used. It has been widely used.
However, solvent-based inkjet inks evaporate a large amount of solvent into the atmosphere, which is not preferable from the viewpoint of environmental load. UV-curable inkjet inks may have skin sensation depending on the monomer used. Since it is necessary to incorporate an expensive ultraviolet irradiation device into the printer body, the applicable fields are limited.

Against this background, recently, inkjet technology has been developed that uses water-based ink, which has a small environmental load and has been widely used as household inkjet ink, for industrial applications (see, for example, Patent Documents 1 and 2). ).
However, since the water-based ink dries the moisture in the ink, it has a problem that the quick-drying property is inferior to that of the solvent-based ink and the image is easily blurred. In particular, when printing is performed at high speed, it is necessary to eject a large amount of ink at one time, so that the ink tends to bleed more easily, and a method of heating during printing has been proposed (see, for example, Patent Document 3).
However, this method also has a problem that bleeding is likely to occur when the number of nozzle rows in one recording head is increased in order to achieve higher speed.

An object of the present invention is to provide an inkjet recording apparatus capable of obtaining an image without bleeding even in an image formed by ink ejected from adjacent nozzle rows.

The above problem is solved by the invention of 1) below.
1) In an inkjet recording apparatus provided with a recording head for dropleting and ejecting a plurality of inks, the plurality of inks contain at least a colorant, a plurality of organic solvents, and water, and the recording heads are different. It has a plurality of nozzle rows for ejecting colored ink, and the number of the plurality of organic solvents contained in the ink ejected from the adjacent nozzle rows is different, or the number is the same, but at least one of them is An inkjet recording apparatus characterized by having different ones.

According to the present invention, it is possible to provide an inkjet recording apparatus capable of obtaining a high-quality image without bleeding even in an image formed by ink ejected from adjacent nozzle rows.

The schematic which shows an example of the inkjet recording apparatus of this invention. The explanatory view of the internal structure of the apparatus main body 101 of FIG. Explanatory drawing of a recording head and its nozzle row.

Hereinafter, the present invention 1) will be described in detail. In addition, since the following 2) to 6) are also included in the embodiment of the present invention 1), these will also be described.
2) The inkjet recording apparatus according to 1), wherein 20 to 80% by mass of the organic solvent contained in each of the plurality of inks is a water-soluble organic solvent having an SP value of 10 or less.
3) The feature is that the number of water-soluble organic solvents having an SP value of 10 or less contained in each ink ejected from the adjacent nozzle rows is different, or the number is the same but at least one of them is different. The inkjet recording apparatus according to 1) or 2).
4) The inkjet recording apparatus according to 2) or 3), wherein the water-soluble organic solvent having an SP value of 10 or less contains a water-soluble organic solvent having a boiling point of less than 180 ° C.
5) The inkjet recording apparatus according to 4), wherein the water-soluble organic solvent having a boiling point of less than 180 ° C. contains a water-soluble organic solvent having a molecular weight of 130 or less.
6) An inkjet recording method comprising recording an image on a non-penetrating recording medium using the inkjet recording apparatus according to any one of 1) to 5).

As a result of examining the composition and composition of inks used for a plurality of nozzle rows in a recording head, the present inventors have adopted the configuration of the present invention 1) so that there is no bleeding even when printing an image of a plurality of colors. Found that an image can be obtained.
The detailed reason why the above effect is obtained is unknown. However, especially in an image in which color boundaries exist in a band shape, in adjacent nozzle rows, when inks having different solvent configurations are ejected onto the base material, the inks of different colors are based on each other after landing on the base material. May come into contact and mix before being fixed on the material. On the other hand, when inks having different solvent configurations as in the present invention are used, it is presumed that the compatibility between inks of different colors is lowered and bleeding is suppressed.
The number of recording heads in the inkjet recording apparatus of the present invention may be one or a plurality, but at least one must have the above-mentioned characteristics.

In the present invention, an ink containing at least a colorant, a plurality of organic solvents, and water is used.
Hereinafter, the ink components will be described in detail.

Examples of the colorant include pigments and dyes, but pigments are preferable.
<Pigment>
Pigments include organic pigments and inorganic pigments, which are appropriately selected and used according to the color of the ink.
As the black pigment, carbon black (Pigment Black 7) is particularly preferable. Its commercial products include Regal (registered trademark), Black Pearls (registered trademark), Elftex (registered trademark), Monarch (registered trademark), Regal (registered trademark), Mogul (registered trademark) and Vulcan (registered trademark). Carbon black available from Cabot Corporation (eg, Black Pearls 2000, 1400, 1300, 1100, 1000, 900, 880, 800, 700, 570, Black Pearls L, Elftex 8, Monarch 1400, 1300, 1100, 1000, 900, 880, 800, 700, Trademark L, Regal 330, 400, 660, Vulcan P), SENSIJET BlackSDP100 (SENSIENT), SENSIJET BlackSDP1000 (SENSIENT) ), SENSIJET BlackSDP2000 (SENSIENT) and the like.

Color pigments include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 128, 139, 150, 151, 155, 153, 180, 183, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 [Permanent Red 2B (Ca)], 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Magenta), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15, 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; C.I. I. Pigment Greens 1, 4, 7, 8, 10, 17, 18, 36, and the like.
Examples of the white pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide and the like.

The pigment ^{preferably has a surface area of 10 to 1500 m 2} / g, more preferably 20 to 600 m ² / g, and even more preferably 50 to 300 m ² / g.
If it does not match the desired surface area, size reduction or pulverization treatment (for example, ball mill pulverization, jet mill pulverization, ultrasonic treatment, etc.) may be performed in order to reduce the particle size of the pigment.
In terms of pigment dispersion stability, ejection stability, image density, and productivity of the ink, the volume average particle diameter (D50) of the pigment in the ink is preferably 10 to 300 nm, more preferably 20 to 250 nm.
The content of the pigment in the ink is preferably about 0.1 to 10% by mass, more preferably about 1 to 10% by mass, in terms of image density, fixability, and ejection stability.
To disperse the pigment in the ink, a method using a surfactant, a method using a dispersible resin, a method of coating the surface of the pigment with a resin, and a self-dispersing pigment by introducing a hydrophilic functional group on the pigment surface. And so on.

<Organic solvent>
The organic solvent contained in the ink is not particularly limited, but a water-soluble organic solvent is preferable.
Examples of water-soluble organic solvents include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, and the like. 1,4-Butanediol, 2-methyl-2,4-pentanediol, diethylene glycol, triethylene glycol, dipropylene glycol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propane Many diols, 1,2-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,5-hexanediol, etc. Valuable alcohols; dipropylene glycol monomethyl ether, propylene glycol-n-butyl ether, propylene glycol-t-butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol benzyl ether, ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether , Dipropylene glycol-n-propyl ether, tripropylene glycol methyl ether, tripropylene glycol-n-propyl ether, propylene glycol phenyl ether, triethylene glycol methyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene Polyhydric alcohol alkyl ethers such as glycol butyl ether, diethylene glycol-n-hexyl ether, ethylene glycol phenyl ether; esters such as ethyl lactate; N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone , 1,3-Dimethylimidazolidinone, nitrogen-containing heterocyclic compounds such as ε-caprolactam; amides such as formamide, N-methylformamide, N, N-dimethylformamide; monoetheranolamine, diethanolamine, triethanolamine, Amines such as monoethylamine, diethylamine and triethylamine; sulfur-containing compounds such as dimethylsulfoxide, sulfolane, thiodiethanol and thiodiglycol can be mentioned.

In the present invention, the ink contains a plurality of organic solvents.
Then, the number of the plurality of organic solvents contained in the ink ejected from the adjacent nozzle rows is changed, or at least one of the plurality of organic solvents is changed when the numbers are the same.
In particular, in the present invention, it is preferable to use a combination of an organic solvent having an SP value of 10 or less and a solvent having an SP value of more than 10.
Further, it is preferable that 20 to 80% by mass of the organic solvent is a water-soluble organic solvent having an SP value of 10 or less, and more preferably 20 to 50% by mass. As a result, the cohesiveness and drying property of the ink are improved, and an excellent effect on bleeding during high-speed printing can be obtained.
Further, as the water-soluble organic solvent having an SP value of 10 or less, a solvent having a boiling point of less than 180 ° C. is preferable, and among them, a solvent having a molecular weight of 130 or less is preferable.

Examples of the water-soluble organic solvent include those shown in Table 1 below. The SP value is a solubility parameter.

The total amount of the water-soluble organic solvent in the ink is preferably in the range of 20 to 70% by mass, more preferably in the range of 30 to 60% by mass. If the total amount is 20% by mass or more, it becomes difficult for the ink to dry, and particularly sufficient ejection stability can be easily obtained. Further, when it is 70% by mass or less, the viscosity of the ink does not become too high, which is advantageous for ejection.
Further, when 20% by mass or more of the water-soluble organic solvent has an SP value of 10 or less, high-speed fixability on a substrate can be obtained, which is preferable.

<Resin particles>
It is desirable to add resin particles to the ink used in the present invention in order to enhance the fastness and gloss of the image.
The type of resin particles is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Can be mentioned. Among these, emulsions of urethane resins and acrylic resins are preferable because they are excellent in fixability and ink stability. Further, the resin particles may contain a dispersant such as a surfactant if necessary, but since it is easy to obtain an ink having excellent coating film performance, so-called self-emulsifying type resin particles are used. preferable. In that case, from the viewpoint of water dispersibility, it is preferable to have an anionic group in the range where the acid value is 5 to 100 mgKOH / g, and in order to impart excellent scratch resistance and chemical resistance, 5 to 50 mgKOH / mg. Is particularly preferable. Further, when the anionic group has a carboxyl group, a sulfonic acid group, or the like, good aqueous dispersion stability can be obtained. In order to introduce these anionic groups into the resin, a monomer having these anionic groups may be used.

As the resin particles, those synthesized appropriately or commercially available products may be used.
Examples of the commercially available products include Superflex 130 (polyether-based urethane resin particles, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), John Krill 537 (acrylic resin particles, manufactured by BASF), Microgel E-1002, and E-5002 (). Styrene-acrylic resin particles, manufactured by Nippon Paint Co., Ltd., Boncoat 4001 (acrylic resin particles, manufactured by Dainippon Ink and Chemicals Co., Ltd.),
Boncoat 5454 (styrene-acrylic resin particles, manufactured by Dainippon Ink and Chemicals Co., Ltd.), SAE-1014 (styrene-acrylic resin particles, manufactured by Nippon Zeon), Cybinol SK-200 (acrylic resin particles, manufactured by Saiden Chemical Co., Ltd.) ), Primal AC-22, AC-61 (acrylic resin particles, manufactured by Roam & Haas), Nanokrill SBCX-2821, 3689 (acrylic silicone resin particles, manufactured by Toyo Ink Mfg. Co., Ltd.), # 3070 (methacrylic acid). Methyl polymer resin particles, manufactured by Gokoku Dye Co., Ltd.) and the like.

The particle size of the resin particles is preferably 10 to 1000 nm in volume average, more preferably 20 to 50 nm in consideration of being used in an inkjet recording device. The volume average particle size can be measured using, for example, a particle size analyzer (Microtrack MODEL UPA9340, manufactured by Nikkiso Co., Ltd.).
The content of the resin particles in the ink is preferably in the range of 1 to 10% by mass from the viewpoint of fixability and ink stability, and the smoothness of the ink layer is improved, the glossiness is high, and the fixability to the substrate is improved. From this point of view, the range of 5 to 10% by mass is more preferable.

<Other additives>
Examples of other additives added to the ink include surfactants, antiseptic and antifungal agents, rust preventives, pH adjusters and the like.
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant.
Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.

Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property.
Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt.
Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt.
The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers.
The counterions of the salts in these fluorine-based surfactants are 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 etc. can be mentioned.

Examples of the antiseptic fungicide include 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, sodium sorbate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide and the like. ..
Examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like.
The pH adjuster is not particularly limited as long as it can adjust the pH to a desired value without adversely affecting the ink to be blended. Examples include hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate; quaternary ammonium hydroxides and the like. Amines such as diethanolamine and triethanolamine; ammonium hydroxide, quaternary phosphonium hydroxide and the like can be mentioned.

The ink used in the present invention can be produced by adding water to each of the above components and stirring and mixing them as necessary. Stirring and mixing can be performed with a stirrer using ordinary stirring blades, a magnetic stirrer, a high-speed disperser, or the like. However, the production method is not particularly limited, and a known method may be appropriately adopted.

<Inkjet recording method>
In the inkjet recording method of the present invention, at least a head having two or more rows of nozzles in one recording head and a plurality of organic solvents contained in inks of adjacent nozzle rows in the recording head are different in number. Alternatively, at least one of the same number of inks has a step of ejecting different inks.
The ink ejection process is a process of applying a stimulus to the ink to cause it to fly and print. The means for flying the ink is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include various recording heads (ink ejection heads). In particular, those having a recording head having a plurality of nozzle rows and a sub-tank for accommodating the ink supplied from the ink cartridge and supplying the ink to the recording head are preferable. The number of nozzle rows is preferably 8 or less. The sub-tank includes a negative pressure generating means for generating a negative pressure in the sub-tank, an air-opening means for opening the inside of the sub-tank to the atmosphere, and a detecting means for detecting the presence or absence of ink by the difference in electrical resistance. It is preferable to have.

The stimulus can be generated, for example, by a stimulus generating means. The stimulus is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferably mentioned.
Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light. Specifically, piezoelectric actuators such as piezoelectric elements, thermal actuators that utilize phase changes due to film boiling of liquids using electrothermal conversion elements such as heat-generating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, Examples include electrostatic actuators that use electrostatic force.

The mode of flight of the ink is not particularly limited, and differs depending on the type of the stimulus and the like. For example, when the stimulus is "heat", heat energy corresponding to the recording signal is applied to the ink in the recording head by using, for example, a thermal head, and the heat energy is used to generate bubbles in the ink, and the bubbles are generated. A method of ejecting ink as droplets from the nozzle hole of the recording head by the pressure of the above can be mentioned. When the stimulus is "pressure", for example, by applying a voltage to the piezoelectric element adhered to a position called a pressure chamber in the ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. There is a method in which the ink is ejected as droplets from the nozzle hole of the recording head.
Above all, a method of applying a voltage to the piezo element to cause the ink to fly is preferable. Since the piezo method does not generate heat, it is advantageous for flying ink containing a resin, and is an effective method with less nozzle clogging, especially when an ink having a low content of a wetting agent is used. Further, in order to prevent the nozzle from coming off, it is preferable to apply a voltage having a strength that does not eject ink to the piezo element to perform an empty scan. Further, it is preferable to perform an operation of ejecting ink to the ink reservoir before reaching a blank scan for printing one page. Further, it is preferable to have a scraping means for scraping off the ink stuck to the empty ejection receiver. As the scraping means, either a wiper or a cutter is preferable.

Further, in the present invention, it is also possible to provide a heating device for heating the base material in order to increase the spread of the ejected ink on the base material.
As the heating means, one or a plurality of known heating devices can be appropriately selected and used. Examples of the heating device include a device for forced air heating, radiant heating, conduction heating, high frequency drying, microwave drying, and the like. Such a heating device may be incorporated in an existing inkjet printer or may be externally attached to an existing inkjet printer.

<Inkjet recording device>
FIG. 1 is a schematic view showing an example of the inkjet recording apparatus of the present invention. Although the following description corresponds to a serial type (shuttle type) inkjet recording device in which a carriage scans, the device of the present invention can also be applied to a line type inkjet recording device provided with a line type head.
The device of FIG. 1 includes a device main body 101, a paper feed tray 102 for loading a base material mounted on the device main body 101, and a paper ejection tray 103 for stocking a printed base material mounted on the device main body 101. And an ink cartridge loading unit 104. An operation unit 105 such as an operation key or a display is arranged on the upper surface of the ink cartridge loading unit 104. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 200. 111 is the upper cover and 112 is the front surface of the front cover.

As shown in FIG. 2, the apparatus main body 101 includes a guide rod 131 and a stay 132 which are guide members horizontally laid on the left and right side plates (not shown), and the carriage 133 can be slidably slidable in the main scanning direction. It is held and moved and scanned by a main scanning motor (not shown).
As shown in FIG. 3, the carriage 133 has one inkjet having four rows of nozzle rows 136 for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). A recording head 134 composed of a recording head is attached.
The inkjet recording head constituting the recording head 134 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change due to boiling of a liquid film using an electrothermal conversion element such as a heat generating resistor, and a metal phase due to a temperature change. A shape memory alloy actuator that uses change, an electrostatic actuator that uses electrostatic force, or the like provided as a stimulus generating means for ejecting ink can be used. Further, it may have a heater mechanism for heating the ink in the recording head.
Further, the carriage 133 is equipped with a sub tank 135 of each color for supplying ink of each color to the recording head 134. The sub tank 135 is replenished with ink supplied from the ink cartridge 200 loaded in the ink cartridge loading unit 104 via an ink supply tube (not shown).

On the other hand, as a paper feed unit for feeding the base material 142 loaded on the base material loading part (press plate) 141 of the paper feed tray 102, the base material 142 is separated and fed one by one from the base material loading part 141. A separation pad 144 facing the half-moon roller [paper feed roller 143] and the paper feed roller 143 and made of a material having a large friction coefficient is provided, and the separation pad 144 is urged toward the paper feed roller 143.
As a transport unit for transporting the base material 142 fed from the paper feed unit on the lower side of the recording head 134, a transport belt 151 for electrostatically adsorbing and transporting the base material 142 and a paper feed unit The counter roller 152 for sandwiching the base material 142 sent via the guide 145 with the transport belt 151 and the base material 142 fed substantially vertically upward are turned by approximately 90 ° and placed on the transport belt 151. A transfer guide 153 for imitating the pattern and a tip pressurizing roller 155 urged on the transfer belt 151 side by the pressing member 154 are provided, and charging is a charging means for charging the surface of the transfer belt 151. A roller 156 is provided.

The transport belt 151 is an endless belt, which is stretched between the transport roller 157 and the tension roller 158 and can circulate in the belt transport direction. The transport belt 151 includes, for example, a surface layer serving as a substrate adsorption surface formed of a resin material having a thickness of about 40 μm [for example, a copolymer of tetrafluoroethylene and ethylene (ETFE)] without resistance control. It has a back layer (medium resistance layer, earth layer) that is made of the same material as the surface layer and whose resistance is controlled by carbon. On the back side of the transport belt 151, a guide member 161 is arranged corresponding to the printing area by the recording head 134. As a paper ejection unit for ejecting the base material 142 recorded by the recording head 134, a separation claw 171 for separating the base material 142 from the transport belt 151, a paper ejection roller 172, and a paper ejection roller 173 are used. After the base material 142 is hot-air dried by the fan heater 174, the base material 142 is output to the paper ejection tray 103 below the paper ejection roller 172.

A double-sided paper feed unit 181 is detachably attached to the back surface of the apparatus main body 101. The double-sided paper feed unit 181 takes in the base material 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds the paper 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.
In this inkjet recording device, the base material 142 is separately fed from the paper feed unit one by one, and the base material 142 fed substantially vertically upward is guided by the guide 145, and the transfer belt 151 and the counter roller 152 are used. It is sandwiched between the two and transported. Further, the tip is guided by the transport guide 153 and pressed against the transport belt 151 by the tip pressurizing roller 155, so that the transport direction is changed by approximately 90 °. At this time, the transport belt 151 is charged by the charging roller 156, and the base material 142 is electrostatically attracted to the transport belt 151 and transported. Therefore, by driving the recording head 134 in response to the image signal while moving the carriage 133, ink droplets are ejected to the stopped base material 142 to record one line, and the base material 142 is conveyed in a predetermined amount. After that, record the next line. When the recording end signal or the signal that the rear end of the base material 142 reaches the recording area is received, the recording operation is ended and the base material 142 is discharged to the paper ejection tray 103.

The base material to be printed by the inkjet recording method of the present invention is a non-porous base material. Here, the non-porous base material is a resin having a surface made of a non-porous material such as a transparent or colored polyvinyl chloride film, a polyethylene terephthalate (PET) film, an acrylic film, a polypropylene film, a polyimide film, and a polystyrene film. Films, laminated papers, coated papers, etc., which do not contain paper components such as wood pulp paper, Japanese paper, synthetic pulp paper, and synthetic fiber paper on the surface.
The inkjet recording method of the present invention can be applied to various types of recording by the inkjet recording method, and is particularly preferably applied to, for example, an inkjet recording printer, a facsimile machine, a copying machine, a printer / fax / copier multifunction device, and the like. Can be done.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, "%" in an example is "mass%".

<Preparation of black pigment dispersion>
-Preparation of polymer solution A-
After sufficiently substituting nitrogen gas in a 1 L flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas introduction tube, a reflux tube, and a dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, and 12.0 g of lauryl methacrylate. , 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer, and 0.4 g of mercaptoethanol were mixed and the temperature was raised to 65 ° C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyl ethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, and azobismethylvalero. A mixed solution of 2.4 g of nitrile and 18 g of methyl ethyl ketone was added dropwise into the flask over 2.5 hours. After the dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added, and the mixture was further aged for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added into the flask to obtain 800 g of polymer solution A having a concentration of 50%.

-Preparation of black pigment dispersion-
After sufficiently stirring 28 g of polymer solution A, 42 g of carbon black (FW100 manufactured by Degussa), 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of water, a roll mill was used. Kneaded. The obtained paste was poured into 200 g of pure water, stirred sufficiently, methyl ethyl ketone and water were distilled off with an evaporator, and this dispersion was subjected to a polyvinylidene fluoride membrane having an average pore size of 5.0 μm in order to further remove coarse particles. Pressure filtration was performed with a filter to obtain a black (Bk) pigment dispersion having a pigment solid content of 15% and a solid content concentration of 20%.

<Preparation of cyan, magenta, yellow, orange, and green pigment dispersions>
Cyan (C), magenta (M), yellow (Y), orange (O), green (G) in the same manner except that the carbon black in the preparation of the black pigment dispersion was changed to each of the following pigments. Each pigment dispersion of the above was obtained.
-Cyan: Copper phthalocyanine pigment manufactured by Toyo Ink Co., Ltd. (CI Pigment Blue 15: 4, trade name: LX4033)
-Magenta: Pigment Red 122 manufactured by Sun Chemical
-Yellow: Yellow pigment manufactured by Dainichiseika Kogyo Co., Ltd. (Pigment Yellow 74, trade name: Yellow NO.46)
-Orange: Clariant's orange pigment (CI Pigment Orange 36, trade name: Novoperm Orange HL)
-Green: Green pigment manufactured by DIC (FASTOGEN Green G-36)

<Preparation of black, cyan, magenta, yellow, orange, and green inks>
The materials of the following formulations were mixed and stirred, and then filtered through a 0.2 μm polypropylene filter to prepare the inks of Examples 1 to 12 and Comparative Examples 1 and 2. The types of pigment dispersion, organic solvent, and resin particles used in each ink, and the blending ratio of the organic solvent are as shown in the columns of Examples and Comparative Examples in Tables 2-1 and 2-2. Is. The numerical values in Tables 2-1 and 2-2 are "mass%".
[Ink prescription]
-Pigment dispersion: Any of the above Bk, M, C, Y, O, G ... 20%
-Organic solvent (SP value 10 or less): (Refer to Table 2-1 and Table 2-2 for the blending amount)
(A) Diethylene glycol diethyl ether (SP value 8.2, boiling point 189 ° C., molecular weight 162.2)
(B) Dipropylene glycol monomethyl ether (SP value 9.7, boiling point 188 ° C., molecular weight 148.2)
(C) Propylene glycol-n-propyl ether (SP value 9.8, boiling point 150 ° C., molecular weight 118.2)
(D) 3-Methoxy-3-methyl-1-butanol (SP value 9.6, boiling point 174 ° C, molecular weight 118.2)
(E) Diethylene glycol dimethyl ether (SP value 8.1, boiling point 162 ° C., molecular weight 134.2)
-Organic solvent (SP value exceeding 10): (Refer to Table 2-1 and Table 2-2 for the blending amount)
(F) 1,3 butanediol (SP value 12.8, boiling point 203 ° C)
(G) 2-Pyrrolidone (SP value 11.2, boiling point 245 ° C)
-Resin particles: Urethane resin particles (Superflex 130, manufactured by Dai-ichi Pharmaceutical Co., Ltd.)
Or, acrylic resin particles (NeoCryl A-2092, manufactured by DSN) ... 20%
・ Surfactant ・ ・ ・ 2%
(H) CH ₃ (CH ₂ ) ₁₂₀ (CH ₂ CH ₂ O) ₃ CH ₂ COOH
(I) Polyfox PF-156A (anionic fluorine-based surfactant, manufactured by OMNOVA)
・ Antiseptic and fungicide: Proxel LV (manufactured by Abyssia) ・ ・ ・ 0.1%
・ Water ・ ・ ・ 17.9%
(The amount of water of "Bk" and "M" in Comparative Example 2 is 7.9%.)

[Examples 1 to 11 and Comparative Examples 1 to 2]
<Recording and evaluation of images>
An inkjet printer equipped with a head consisting of four rows of nozzles in one head, and modified so that black ink in the first row, cyan in the second row, magenta in the third row, and yellow ink in the fourth row can be mounted. (Ricoh IPSiO GXe5500 remodeling machine) is filled with each ink, and a solid image of each color is adjacent to a white PVC sheet (glossy PVC gray glue S CF: manufactured by Sakurai), which is a non-porous base material. (Strip pattern) was printed.
The "bleeding at the color boundary" of the obtained image was evaluated by visual observation according to the following criteria. The results are shown in Table 3, and it can be seen that an image without blurring can be obtained in the examples.
〔Evaluation criteria〕
A: No bleeding B: Very slight bleeding is confirmed in some places C: Bleeding is confirmed in the entire boundary D: Bleeding is observed in the entire band pattern

[Example 12]
<Recording and evaluation of images>
One head is equipped with a head consisting of 6 rows of nozzles, black in the 1st row, cyan in the 2nd row, magenta in the 3rd row, yellow in the 4th row, orange in the 5th row, and 6th row. An inkjet printer (IPSiO GXe5500 remodeling machine manufactured by Ricoh Co., Ltd.) modified so that green ink can be mounted is filled with each ink, and a white PVC sheet with a non-porous base material (glossy PVC gray glue S CF: manufactured by Sakurai Co., Ltd.) A test pattern in which a character image and a solid image of each color are adjacent to each other is printed.
The "bleeding of the color boundary portion" of the obtained image was evaluated in the same manner as in the cases of Examples 1 to 11. The results are shown in Table 3, and it can be seen that an image without blurring can be obtained in the examples.

101 Device body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading unit 105 Operation unit 111 Top cover 112 Front 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 136 Nozzle row 141 Base material mounting unit 142 units Material 143 Paper feed roller 144 Separation pad 145 Guide 151 Conveyance belt 152 Counter roller 153 Conveyance guide 154 Pressing member 155 Pressurizing roller 156 Charging roller 157 Conveying roller 158 Tension roller 161 Guide member 171 Separation claw 172 Paper ejection roller 173 Double-sided paper feed unit 182 Manual paper feed unit 200 Ink cartridge

Japanese Unexamined Patent Publication No. 2005-220352 Japanese Unexamined Patent Publication No. 2011-094082 Japanese Unexamined Patent Publication No. 2011-2012230

Claims (6)

In an inkjet recording device provided with a recording head for dripping and ejecting a plurality of inks.
At least one recording head
A first nozzle row that ejects ink of the first color and a second nozzle that ejects ink of a second color different from the ink of the first color adjacent to the first nozzle row. I have a column,
A plurality of the first color inks and the second color inks contain at least a colorant, a plurality of organic solvents, and water, and are contained in the first color inks and the second color inks. The number of organic solvents is different, or the number is the same, but at least one of them is different, and the total amount of a plurality of organic solvents contained in each of the first color ink and the second color ink. Is an inkjet recording apparatus, characterized in that the content is 20 to 70% by mass. The inkjet recording apparatus according to claim 1, wherein the colorant is a pigment, and the content of the pigment in the ink is 0.1 to 10% by mass. 20 to 80% by mass of the organic solvent contained in each of the plurality of inks is diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, propylene glycol-n-propyl ether, 3-methoxy-3-methyl-1-. The inkjet recording apparatus according to claim 1 or 2, wherein the inkjet recording apparatus is at least one selected from butanol and diethylene glycol dimethyl ether. The first color ink and the plurality of organic solvents contained in the second color ink are a combination of diethylene glycol diethyl ether and 1,3-butanediol, dipropylene glycol monomethyl ether and 1,3-butanediol. Combination of propylene glycol-n-propyl ether and 1,3-butanediol, combination of 3-methoxy-3-methyl-1-butanol and 1,3-butanediol, dipropylene glycol monomethyl ether and 2-pyrrolidone. , A combination of diethylene glycol diethyl ether, 3-methoxy-3-methyl-1-butanol and 1,3-butanediol, a combination of diethylene glycol diethyl ether, diethylene glycol dimethyl ether and 1,3-butanediol, diethylene glycol diethyl ether and dipropylene. Combination of glycol monomethyl ether and 1,3-butanediol, combination of diethylene glycol diethyl ether, 1,3-butanediol and 2-pyrrolidone, propylene glycol-n-propyl ether and 3-methoxy-3-methyl-1-butanol Either a combination of 1,3-butanediol and a combination of 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methyl-1-butanol and 1,3-butanediol. an ink jet recording apparatus according to claim 1, characterized in that. The inkjet recording apparatus according to any one of claims 1 to 4, wherein each ink ejected from adjacent nozzle rows contains urethane resin particles or acrylic resin particles. An inkjet recording method comprising recording an image on a non-penetrating recording medium using the inkjet recording apparatus according to any one of claims 1 to 5.

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