JP2008023727A - Ultraviolet irradiating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet irradiating device which can prevent an ultraviolet light from reaching a head nozzle and can prevent clogging of the head nozzle by irradiating the ultraviolet light less in diffusion of light. <P>SOLUTION: The ultraviolet irradiating device 90 is attached to a carriage 50 which carries the head nozzle that jets ink of an ultraviolet curing type. The ultraviolet irradiating device 90 is equipped with a plurality of light sources 95a, 95b, 95c and 95d which irradiates the jetted ink with the ultraviolet light. The light sources 95a and 95b set near the head nozzle irradiate the ultraviolet light less in diffusion of light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultraviolet irradiation apparatus that is attached to a carriage on which a head nozzle that ejects ultraviolet curable ink is mounted and includes a plurality of light sources that irradiate the ejected ink with ultraviolet light.

In recent years, ultraviolet curable inks have attracted attention as inks used in inkjet printers and the like. UV curable ink differs from normal water-based ink or oil-based ink in that it adheres to a recording medium (for example, printing paper) and then quickly cures when irradiated with an appropriate amount of ultraviolet light to record ink permeability. A stable print quality can be maintained regardless of the physical properties of the medium. In an ink jet printer using such an ultraviolet curable ink, the ink deposited on the recording medium is irradiated with ultraviolet rays around the head nozzle that ejects the ultraviolet curable ink as fine ink droplets and adheres to the recording medium. It is necessary to equip the ultraviolet irradiation device which performs (refer patent document 1, 2).
JP 2004-358769 A JP 2005-103854 A

  When an ultraviolet irradiation device is placed near the carriage on which the head nozzle for ejecting ultraviolet curable ink is mounted, the ultraviolet light reaches the head nozzle, and the ink adhering to the head nozzle is cured, causing the nozzle to be clogged. There is a case. An object of the present invention is to prevent clogging of a head nozzle.

  The present invention is an ultraviolet irradiation apparatus that is attached to a carriage on which a head nozzle that ejects ultraviolet curable ink is mounted, and includes a plurality of light sources that irradiate ultraviolet light to the ejected ink, in the vicinity of the head nozzle The light source provided in irradiates ultraviolet light with little light diffusion. According to this configuration, it is possible to prevent the ultraviolet light from reaching the head nozzle by irradiating the ultraviolet light with less light diffusion, and therefore, the clogging of the head nozzle can be prevented.

  In the present invention, the light source provided in the vicinity of the head nozzle emits ultraviolet light having a narrow directivity. According to this configuration, it is possible to reduce light diffusion by using a light source with narrow directivity.

  In the present invention, a lens for collecting ultraviolet light emitted from a light source provided near the head nozzle is provided. According to this configuration, the diffusion of light can be reduced by collecting the ultraviolet light.

  The present invention is an ultraviolet irradiation apparatus including a head nozzle that ejects ultraviolet curable ink and a plurality of light sources that are provided in a carriage on which the head nozzle is mounted and that radiates ultraviolet light to the ejected ink. Then, the ultraviolet light irradiation direction of the light source provided in the vicinity of the head nozzle is a direction away from the head nozzle. According to this configuration, the irradiation direction can be changed by tilting the light source in the direction away from the head nozzle, and ultraviolet light can be prevented from reaching the head nozzle, thus preventing clogging of the head nozzle. can do.

  In the present invention, the light source is at least one selected from a mercury lamp, a metal halide lamp, a xenon lamp, an excimer lamp, an LED, and an LD.

  According to the present invention, it is possible to prevent the ultraviolet light from reaching the head nozzle by irradiating the ultraviolet light with less light diffusion, so that the clogging of the head nozzle can be prevented.

  According to the present invention, the irradiation direction can be changed by inclining the light source in the direction away from the head nozzle, and ultraviolet light can be prevented from reaching the head nozzle, thereby preventing clogging of the head nozzle. can do.

  FIG. 1 is a schematic perspective view showing a main configuration of an embodiment of an inkjet printer 20 equipped with an ultraviolet irradiation device according to the present invention. The printer 20 includes a paper feed motor 30 that feeds printing paper P that is a recording medium, a platen 40, an ink head 52 that sprays and adheres photocurable ink to the printing paper P with a fine particle size, and an ink head 52. , A carriage motor 60 that moves the carriage 50 in the main scanning direction, and an ultraviolet irradiation device that irradiates the ink adhering surface on the printing paper P on which the ultraviolet curable ink is adhered by the ink head 52. 90.

  The carriage 50 is pulled by a pulling belt 62 driven by a carriage motor 60 and moves along a guide rail 64. In addition to the ink head 52, the carriage 50 includes a black cartridge 54 as a black ink container that contains black ink supplied to the ink head 52, and a color ink container that contains color ink supplied to the ink head 52. The color ink cartridge 56 is mounted. The ink contained in each of the cartridges 54 and 56 is ultraviolet curable ink that is cured by irradiation with ultraviolet light or visible light in the vicinity thereof.

  A capping device 80 for sealing the nozzle surface of the ink head 52 when stopped is provided at the home position of the carriage 50 (the position on the right side in FIG. 1). When the print job ends and the carriage 50 reaches the top of the capping device 80, the capping device 80 is automatically raised by a mechanism (not shown) to seal the nozzle surface of the ink head 52. Capping prevents the ink in the nozzles from drying. The positioning control of the carriage 50 is performed to accurately position the carriage 50 at the position of the capping device 80, for example.

  FIG. 2 shows the configuration of the ultraviolet irradiation device 90. The ultraviolet irradiation device 90 includes light sources 95a and 95b provided at the near end of the carriage 50 on which the ink head is mounted, light sources 95c and 95d provided at the far end of the carriage 50, and a drive circuit that controls light emission and extinction of each light source. (See FIG. 3). Although FIG. 2 shows a case where one ultraviolet irradiation device is attached to one side of the carriage 50, it may be attached to both sides of the carriage 50. Moreover, when attaching to one side, it may be on either side of the carriage 50.

  Since the light emitted from the light source is diffused and reaches the printing paper P, a wider diffusion range can be emitted by a single light source. However, when the diffused ultraviolet light reaches the head nozzle, the ultraviolet curable ink adhering to the head nozzle is cured and the head nozzle is clogged. Therefore, the light sources 95a and 95b close to the ink head 52 are not diffused. This reduces the amount of ultraviolet light reaching the head nozzle. In order to irradiate light with less diffusion, a light source with narrow directivity is used, or the irradiated light is collected by a lens. Further, instead of using a light source with little diffusion, the light sources 95a and 95b close to the ink head 52 may be inclined so that the ultraviolet ray direction is away from the head nozzle.

  Photocurable inks have a difference in the wavelength range of light absorbed when irradiated due to differences in colorant components (pigments or dyes, etc.) and other component compositions. There may be differences in the curing time. Therefore, by using light sources with different emission wavelength peaks in the arrangement of multiple light sources, it is possible to irradiate light in a wide wavelength range with multiple emission peaks, and light of some emission wavelength peaks is absorbed. However, the light having other emission wavelength peaks contributes effectively to the curing of the ink, so that the curing efficiency of the ink can be stably maintained, and the emission wavelength peaks of the irradiation light to be absorbed are different. It is possible to cope with photocurable ink. As a result, the corresponding ink types can be increased, and the versatility as the ultraviolet irradiation device 90 can be improved. Applicable light sources are preferably mercury lamps, metal halide lamps, xenon lamps, excimer lamps, LEDs, and LDs.

  In this embodiment, light source diode model number NCCU001E (peak emission wavelength 380 nm, directivity characteristic 55 °) manufactured by Nichia Corporation is used as the light source 95a, 95b with little directivity provided at the near end of the carriage 50. As light sources 95c and 95d provided at the ends, Nichia Corporation light emitting diode model number NCCU033 (peak emission wavelength 365 nm, directivity 100 °) was used.

The ultraviolet irradiation device 90 having the above-described configuration is attached to the carriage 50, and at the position where the distance from the printing paper P is 5 mm, the ultraviolet curable ink described in the following example is discharged from the ink head and at the same time, the ultraviolet light (irradiation intensity 60 mW / cm ² , Irradiation with a wavelength range of 365 to 380 nm), even after forming an image by discharging and curing ultraviolet curable ink onto the printing paper P, neither thickening nor curing of the ink that causes clogging of the head nozzle is observed. It was. The light emission wavelength of the light source is preferably selected according to the characteristics of the photocurable ink to be processed. Depending on the characteristics of the photocurable ink, it can be suitably used in addition to the light emission wavelengths shown above. It is possible to select one.

  Next, the electrical configuration of the printer 20 will be described with reference to FIG. FIG. 3 is a block diagram showing an electrical configuration of the printer 20. The printer 20 includes a main control circuit 102, a CPU 104, and various memories (ROM 110, RAM 112, EEPROM 114) connected to the main control circuit 102 and the CPU 104 via a bus. The main control circuit 102 includes an interface circuit 120 that transmits and receives signals to and from an external device such as a personal computer, a paper feed motor drive circuit 130, a head drive circuit 140, a CR motor drive circuit 150, and ultraviolet irradiation. A drive circuit 160 that controls the operation of the device 90 is connected.

  The paper feed motor 30 is driven by the paper feed motor drive circuit 130 to rotate the paper feed roller 34, thereby moving the printing paper P in the transport direction. The paper feed motor 30 is provided with a rotary encoder 32, and an output signal of the rotary encoder 32 is input to the main control circuit 102.

  An ink head 52 having a plurality of nozzles (not shown) is provided on the bottom surface of the carriage 50. Each nozzle is driven by a head driving circuit 140 and ejects ink droplets of photocurable ink supplied from the cartridges 54 and 56 toward printing paper such as paper, cloth, and film.

  The carriage motor 60 is driven by a CR motor driving circuit 150. The printer 20 includes a linear encoder 70 for detecting the position and speed of the carriage 50 along the main scanning direction. The linear encoder 70 includes a linear code plate 72 provided parallel to the main scanning direction and a photo sensor 74 provided on the carriage 50. The output signal of the linear encoder 70 is input to the main control circuit 102.

  The drive circuit 160 controls light emission and extinction of each light source 95 based on a control signal sent from the main control circuit 102. Specifically, when the ink head 52 is driven and printing is started, or when the printing operation is started, the photocuring ink adhering surface on the printing paper P is in a specific wavelength region by the ultraviolet irradiation device 90. When the light irradiation area 98 is reached, all the light sources mounted on the support means 91 are made to emit light, and the light curable ink adhering surface on the printing paper P is irradiated with light in a specific wavelength region by the ultraviolet irradiation device 90. The light emission state of each light source is maintained until it passes through 98. That is, each light source is caused to emit light continuously until the surface of the photocurable ink adhering surface on the printing paper P finishes passing through the light irradiation region 98 of the specific wavelength region by the ultraviolet irradiation device 90.

  The main control circuit 102 has a function of supplying control signals to the four drive circuits 130, 140, 150, and 160, respectively, and decodes various print commands received by the interface circuit 120 and print data It also has a function of executing control related to adjustment and monitoring of various sensors. On the other hand, the CPU 104 has various functions for assisting the main control circuit 102, and executes control of various memories, for example.

  The light source in the ultraviolet irradiation device 90 emits light continuously during the printing process. However, the characteristics of the photo-curable ink used and the printing area are controlled so as to minimize the amount of light applied to the ink. Based on information (e.g., the amount of light-curing ink sprayed and applied), the light source may be caused to emit light in pulses at regular time intervals. As a result, the amount of light applied to the photocurable ink can be controlled to the minimum necessary to reduce the power consumption in the ultraviolet irradiation device 90, the heat generation of the light source, and the longer life by shortening the working time of the light source. it can.

  In addition, the apparatus equipped with the ultraviolet irradiation device of the present invention is not limited to an ink jet printer. It can be mounted on various devices for attaching photocurable ink. Various materials such as paper, film, cloth, metal thin plate, etc. can be considered as the material of the printing paper that irradiates light in a specific wavelength region by the ultraviolet irradiation device.

  The photocurable ink that can be cured by the ultraviolet irradiation device is not particularly limited. For example, JP-A-3-216379, JP-A-5-186725, JP-B-5-54667, and JP-A-6 -200204, JP-A-7-224241, JP-A-8-48922, JP-A-8-21816, JP-A-10-7956, JP-A-10-250052, JP-A-10-324836. JP, 2000-44857, 2000-119574, 2000-158793, 2000-186242, 2000-186243, 2000-336295 Special Table 2000-504778, Special Table 2001-512777, Special JP 2001-220526 A, JP 2002-80767 A, JP 2003-191593 A, JP 2003-191594 A, JP 2003-31476 A, JP 2004-27154 A, US Pat. No. 5,632,001. And publicly known ones such as the specification of the issue.

  Among them, particularly preferred are those containing a polymerizable compound, a photopolymerization initiator and a polymerization accelerator, an N-vinyl compound as the polymerizable compound, and bisacylphosphine oxide and monoacylphosphine oxide as the photopolymerization initiator. And two or more selected from α-amino ketones.

As described above, the bisacylphosphine oxide, monoacylphosphine oxide and α-aminoketone used in the ink composition all absorb light having a wavelength of 365 nm or more. Monoacylphosphine oxide absorbs in a longer wavelength region than α-aminoketone.
Examples of the bisacylphosphine oxide include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, which is available under the trade name Irgacure 819 (manufactured by Ciba Specialty Chemicals). is there.
Examples of the monoacylphosphine oxide include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, which can be obtained under the trade name of Darocur TPO (manufactured by Ciba Specialty Chemicals).
Examples of the α-aminoketone include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, which is a trade name of Irgacure 369 (manufactured by Ciba Specialty Chemicals). Is available at

The photocurable ink may be used in combination with another photopolymerization initiator as long as it contains at least two types of photopolymerization initiators.
Typical other photopolymerization initiators that may be used in combination include benzoin methyl ether, benzoin ethyl ether, isopropyl benzoin ether, isobutyl benzoin ether, 1-phenyl-1,2-propanedione-2. Examples include-(o-ethoxycarbonyl) oxime, benzyl, diethoxyacetophenone, benzophenone, chlorothioxanthone, 2-chlorothioxanthone, isopropylthioxanthone, diethylthioxanthone, 2-methylthioxanthone, polyphenyl chloride, hexachlorobenzene and the like. Preferred are isobutyl benzoin ether and 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime.

Also, Vicure 10, 30 (manufactured by Stauffer Chemical), Irgacure 127, 184, 500, 651, 2959, 907, 379, 754, 1700, 1800, 1850, OXE01, Darocur 1173, ITX (manufactured by Ciba Specialty Chemicals), Quantacure CTX, ITX (manufactured by Aceto Chemical), Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.), ESACURE KIP150 (manufactured by Lamberti), and a photopolymerization initiator available under the trade names of Lucirin TPO (manufactured by BASF) Can be used.

The polymerizable compound contained in the photocurable ink may contain at least an N-vinyl compound.
Examples of the N-vinyl compound include N-vinylformamide, N-vinylcarbazole, N-vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, and derivatives thereof.

Further, the photocurable ink may contain other polymerizable compound other than the N-vinyl compound as the polymerizable compound.
The other polymerizable compound is not particularly limited as long as it is polymerized by radicals or ions generated from a photopolymerization initiator. Such a polymerizable compound refers to a molecule that can be a structural unit of a basic structure of a polymer. Such a polymerizable compound is also called a photopolymerizable monomer, and includes a monofunctional monomer, a bifunctional monomer, and a polyfunctional monomer.

  As typical examples of such polymerizable compounds, monofunctional monomers include (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, (2-methyl-2-isobutyl- 1,3-dioxolan-4-yl) methyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, methoxydiethylene glycol monoacrylate, acroylmorpholine, lauryl methacrylate, allyl glycol, 2-hydroxyethyl methacrylate, cyclohexyl methacrylate, oxetane A methacrylate etc. can be mentioned.

  Bifunctional monomers include ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, polyethylene glycol # 400 diacrylate, tetraethylene glycol dimethacrylate 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, hydroxypioperic acid ester neo Examples include pentyne glycol diacrylate.

  As the polyfunctional monomer, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane EO adduct triacrylate, trimethylolpropane PO adduct triacrylate, glycerin EO adduct triacrylate, glycerin EO modified triacrylate, Examples include glycerin PO adduct triacrylate, pentaerythritol triacrylate, dipentaerythrole hexaacrylate, hydrogen phthalate- (2,2,2-triacroyloxymethyl) ethyl, dipentaerythritol polyacrylate, and the like. it can.

  Among the monofunctional monomers, bifunctional monomers, and polyfunctional monomers used in combination with N-vinyl compounds, preferably acroylmorpholine (monofunctional monomer), phenoxyethyl acrylate (monofunctional monomer), tripropylene glycol diacrylate ( Bifunctional monomer), hydrogen phthalate- (2,2,2-triacroyloxymethyl) ethyl (polyfunctional monomer), glycerin EO-modified triacrylate (polyfunctional monomer), but limited to these combinations It is not a thing.

The polymerization accelerator contained in the photo-curable ink may contain at least fine particles having a polymerizable functional group.
The mechanism for promoting the polymerization of fine particles introduced with polymerizable functional groups is not clear, but radicals generated by photopolymerization initiators that absorb and cleave ultraviolet rays are trapped and stabilized on the surface of the fine particles, and introduced into the surface of the fine particles. It is presumed that the polymerization reaction is facilitated by easily starting the polymerization reaction with the polymerizable functional group and the polymerizable compound adsorbed on the surface.

The fine particles having a polymerizable functional group are not particularly limited, but are generally called extender pigments, and examples thereof include inorganic compounds such as silica, alumina, titania, calcium oxide, and particularly, silica, alumina, and the like. Transparent materials can also be suitably used, and silica is particularly preferable among them.
The polymerizable functional group possessed by the fine particles is not particularly limited, and examples thereof include an acryloyl group and a methacryloyl group, and can also be a polymerizable functional group having one or more double bonds. .
The size of the fine particles is not particularly limited, but those having a particle size of 10 to 200 nm are preferable.
The method for preparing the fine particles having a polymerizable functional group is not particularly limited, but silica fine particles having a large number of hydroxyl groups are produced by a sol-gel reaction of a silane compound such as tetraethoxysilane, and the polymerizable functional group is imparted to the hydroxyl groups. The method of making it react with such a compound (silane coupling agent) is mentioned.
The content of the fine particles having a polymerizable functional group in the photocurable ink composition is not particularly limited, and is appropriately selected according to the use form, conditions, the relationship between the viscosity and the polymerizable property of the ink composition, and the like. Although it should be, it is preferably 10% by mass or less based on the total amount of the ink composition.

The photocurable ink may contain a polymerization accelerator other than polymerizable fine particles.
The other polymerizable compound is not particularly limited, but an aminobenzoate derivative is particularly preferable because the problem of odor and the curing of the ink composition become more reliable. This is because the aminobenzoate derivative reduces polymerization inhibition by oxygen.
The aminobenzoate derivative does not absorb in the wavelength region of 350 nm or more. Examples of such aminobenzoate derivatives include, but are not limited to, ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, etc., which include Darocur EDB, EHA (Ciba Specialty Chemicals) Product name).

The photocurable ink composition also contains a color material.
The color material contained in the photocurable ink composition may be either a dye or a pigment, but it suppresses the penetration of coloring components in the ink composition by the action of insolubilization or thickening of the ink composition. In this case, the pigment dispersed is more advantageous than the dye dissolved in the ink, and the pigment is more advantageous from the viewpoint of image durability of the printed matter.
Examples of the dye used in the photocurable ink composition include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, and reactive disperse dyes. Various dyes used for recording can be used.

As the pigment used in the photocurable ink, inorganic pigments and organic pigments can be used without any particular limitation.
As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

  Specific examples of the pigment include carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B, etc. are Raven 5750, 5250, 5000, 3500, 1255, 700, etc. made by Columbia, and Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, 1400, etc. are Degussa Color Black FW1, FW2, FW2V, FW18, FW200, Color Black S150, S160, S170, Printex. 35, U, V, 140U, Special Black 6, 5, 4A, 4 and the like.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185 and the like.
Examples of pigments used for magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment violet 19 and the like.
Further, examples of pigments used for cyan ink include C.I. I. And CI Pigment Blue 1, 2, 3, 15: 3, 15: 4, 60, 16, and 22.

According to a preferred embodiment of the photocurable ink, the pigment preferably has an average particle size in the range of 10 to 200 nm, more preferably about 50 to 150 nm.
The addition amount of the coloring material in the ink composition is preferably in the range of about 0.1 to 25% by weight, more preferably in the range of about 0.5 to 15% by weight.

According to a preferred embodiment of the photocurable ink, these pigments are preferably added to the ink composition as a pigment dispersion obtained by dispersing the pigment in an aqueous medium with a dispersant or a surfactant. As a preferable dispersant, a dispersant conventionally used for preparing a pigment dispersion, for example, a polymer dispersant can be used. It will be apparent to those skilled in the art that the dispersant and surfactant contained in the pigment dispersion also function as the dispersant and surfactant of the ink composition.
Specifically, polyacrylic acid, polyacrylic acid-styrene copolymer, polyester, polyurethane, polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, vinyl chloride-modified polyacrylic acid, polyoxyalkylene-added polyalkyleneamine And polymer dispersants such as polyvinyl butyral, silicone surfactants such as polyester-modified polydimethylsiloxane and polyether-modified polydimethylsiloxane, acetylenic diol surfactants, and sorbitan surfactants.

The photocurable ink may contain an aqueous solvent. Furthermore, resin emulsions, inorganic oxide colloids, wetting agents, pH adjusting agents, preservatives, fungicides and the like may be added as optional components.
Further, it is more preferable that the photocurable ink composition does not contain an organic solvent and is a solventless ink composition.

  Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

1. Preparation of Polymerizable Fine Particle 1 and Dispersion Solution Silica Sol IPA-ST (manufactured by Nissan Chemical Industries, Ltd., dispersion of isopropyl alcohol (hereinafter referred to as “IPA”) having a silica concentration of 30 wt%) 88.1 parts by weight of a 200 mL Erlenmeyer flask In addition to the above, 7.9 parts by weight of silane coupling agent Silaace S710 (3-methacryloxypropyltrimethoxysilane, manufactured by Chisso Corporation) was added. While stirring with a magnetic stirrer, 4 parts by weight of 0.05 mol / L hydrochloric acid was added, and the reaction was carried out with stirring at room temperature for 24 hours. As a result, an IPA dispersion A containing polymerizable fine particles 1 (MPS) having a methacryl group was obtained.
To a 300 mL round bottom flask, 70 parts by weight of N-vinylformamide (hereinafter also referred to as “NVF”, beam set 770, manufactured by Arakawa Chemical Industries) and 100 parts by weight of the above dispersion A were added, and IPA was added using a rotary evaporator. Then, a dispersion B containing 30 wt% of the polymerizable fine particles 1 was obtained.

2. 2. Preparation of pigment dispersion 2-1. (Yellow) Pigment dispersion C
C.I. as a pigment as a color material I. Pigment Yellow (PY) 74, polyurethane resin (average molecular weight of about 20,000) (hereinafter also referred to as “dispersant”), and NVF are mixed in a ratio of pigment: dispersant: NVF = 15: 5: 80. Then, it was dispersed in a sand mill (manufactured by Yasukawa Seisakusho) with glass beads (diameter 1.7 mm, 1.5 times the weight of the mixture) for 2 hours. Thereafter, the glass beads were separated to prepare a pigment dispersion C (pigment concentration: 15 wt%).

2-2. (Magenta) Pigment dispersion D
The pigment is C.I. I. Pigment dispersion D (pigment concentration 15 wt%) was prepared in the same manner as Pigment dispersion C, except that Pigment Red (PR) 122 was used.
2-3. (Cyan) Pigment dispersion E
The pigment is C.I. I. Pigment dispersion E (pigment concentration: 15 wt%) was prepared in the same manner as Pigment dispersion C except that Pigment Blue (P.B.) 15: 3 was used.
2-4. (Black) Pigment dispersion F
The pigment is C.I. I. A pigment dispersion F (pigment concentration: 15 wt%) was prepared in the same manner as the pigment dispersion C except that the pigment black (P.Bk.) 7 was used.

3. 3. Preparation of ink composition 3-1. Yellow pigment ink composition (Y)
To a light-shielding container, 20 parts by weight of dispersion B and 10 parts by weight of pigment dispersion C are added, 29 parts by weight of NVF, tripropylene glycol diacrylate (hereinafter also referred to as “TPGDA”, Aronix M-220, Toa Gosei Co., Ltd.) 25 parts by weight, glycerin EO-modified triacrylate (hereinafter also referred to as “AGE3”, HK ester A-Gly-3E, Shin-Nakamura Chemical Co., Ltd.) 10 parts by weight, Irgacure 819 (bis (2,4,6-trimethylbenzoyl) ) -Phenylphosphine oxide, manufactured by Ciba Specialty Chemicals Co., Ltd.) 4.0 parts by weight, Irgacure 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, manufactured by Ciba Specialty Chemicals Co., Ltd. ) 1.0 part by weight, Darocur EHA (2-D Add 1 part by weight of ruhexyl-4-dimethoxyaminobenzoate (manufactured by Ciba Specialty Chemicals), stir and mix with a magnetic stirrer for 1 hour, and filter using a 5 μm membrane filter in an environment shielded from ultraviolet rays. A yellow ink composition having the following composition was prepared.

NVF 51 wt%
TPGDA 25 wt%
AGE3 10 wt%
Dispersant 0.5wt%
Irgacure 819 4.0wt%
Irgacure 369 1.0wt%
Darocur EHA 1.0wt%
Polymerizable fine particle 1 6.0 wt%
C. I. Pigment Yellow 74 (coloring material) 1.5wt%

3-2. Magenta, Cyan, and Black Pigment Ink Compositions Similarly, ink compositions having the following compositions were prepared using dispersions D, E, and F, respectively, instead of dispersion C.

Magenta pigment ink composition (M)
NVF 51 wt%
TPGDA 25 wt%
AGE3 10 wt%
Dispersant 0.5wt%
Irgacure 819 4.0wt%
Irgacure 369 1.0wt%
Darocur EHA 1.0wt%
Polymerizable fine particle 1 6.0 wt%
C. I. Pigment Red 122 (coloring material) 1.5wt%

Cyan pigment ink composition (C)
NVF 51 wt%
TPGDA 25 wt%
AGE3 10 wt%
Dispersant 0.5wt%
Irgacure 819 4.0wt%
Irgacure 369 1.0wt%
Darocur EHA 1.0wt%
Polymerizable fine particle 1 6.0 wt%
C. I. Pigment Blue 15: 3 (coloring material) 1.5wt%

Black pigment ink composition (K)
NVF 51 wt%
TPGDA 25 wt%
AGE3 10 wt%
Dispersant 0.5wt%
Irgacure 819 4.0wt%
Irgacure 369 1.0wt%
Darocur EHA 1.0wt%
Polymerizable fine particle 1 6.0 wt%
C. I. Pigment Black 7 (coloring material) 1.5wt%

The figure which shows the main structures of one Embodiment of the inkjet printer carrying the ultraviolet irradiation device which concerns on this invention The figure which shows schematic structure of the ultraviolet irradiation device shown in FIG. The figure which shows the electrical structure in the inkjet printer shown in FIG.

Explanation of symbols

  20: inkjet printer, 30: paper feed motor, 32: rotary encoder, 34: paper feed roller, 40: platen, 50: carriage, 52: ink head (recording head), 54: black cartridge, 56: color ink cartridge, 60: Carriage motor, 62: Traction belt, 64: Guide rail, 70: Linear encoder, 72: Code plate, 74: Photo sensor, 80: Capping device, 90: UV irradiation device, 95: Light emitting device, 102: Main control Circuit: 104: CPU, 110: ROM, 112: RAM, 114: EEPROM, 120: Interface circuit, 130: Paper feed motor drive circuit, 140: Head drive circuit, 150: CR motor drive circuit, 160: UV irradiation device drive Circuit, P: Printing paper (recording medium)

Claims (5)

An ultraviolet irradiation device provided with a plurality of light sources for irradiating ultraviolet light to the ejected ink, attached to a carriage mounted with a head nozzle for ejecting ultraviolet curable ink,
An ultraviolet irradiation apparatus characterized in that a light source provided near the head nozzle irradiates ultraviolet light with little light diffusion. 2. The ultraviolet irradiation apparatus according to claim 1, wherein the light source provided in the vicinity of the head nozzle irradiates ultraviolet light having a narrow directivity characteristic. The ultraviolet irradiation apparatus according to claim 1, further comprising a lens that collects ultraviolet light irradiated from a light source provided in the vicinity of the head nozzle. An ultraviolet irradiation apparatus comprising: a head nozzle that ejects ultraviolet curable ink; and a plurality of light sources that are provided on a carriage that mounts the head nozzle and that radiates ultraviolet light to the ejected ink.
An ultraviolet irradiation apparatus, wherein an ultraviolet light irradiation direction of a light source provided in the vicinity of the head nozzle is a direction away from the head nozzle. The ultraviolet light irradiation apparatus according to any one of claims 1 to 4, wherein the light source is at least one selected from a mercury lamp, a metal halide lamp, a xenon lamp, an excimer lamp, an LED, and an LD.

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