JP2010030120A - Fluid ejection apparatus and fluid curing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid ejection apparatus or the like curing a fluid ejected to a medium in the preferable state. <P>SOLUTION: The fluid ejection apparatus includes: a nozzle for ejecting the fluid having UV-curable property to the medium; a medium conveyance part which conveys the medium in the conveyance direction while causing the medium to face the nozzle; and a plurality of UV light sources which are arranged on the downstream side from the nozzle in the conveyance direction and irradiate the fluid ejected on the medium with UV rays such that a part of UV rays of each light source overlaps with those of adjacent light source toward the medium. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid ejection apparatus and a fluid curing method for curing an ultraviolet curable fluid by irradiating ultraviolet rays onto an ultraviolet curable fluid discharged onto a medium.

An image recording apparatus using, for example, an ultraviolet curable ink is already known as a fluid of a fluid ejecting apparatus that ejects fluid onto a medium. In such an image recording apparatus, a plurality of ultraviolet irradiation devices each irradiating a range of about 1 cm ² are arranged vertically and horizontally, and ultraviolet rays are irradiated to each predetermined region of the medium on which the ultraviolet curable ink is ejected. The ultraviolet curable ink is cured (see, for example, Patent Document 1).
JP 2004-181951 A

  The ultraviolet curable ink is cured by photopolymerization when irradiated with ultraviolet rays. As the ultraviolet energy emitted from the light source increases, the curability of the ink improves. However, the light source generates heat and the ultraviolet light emission efficiency decreases. For this reason, it is conceivable to arrange a plurality of light sources with suppressed outputs side by side in the medium transport direction, and sequentially irradiate ultraviolet rays emitted from each light source, but sequentially irradiate ultraviolet rays emitted from different light sources. Then, when the ink is cured, it takes time until the ink is cured (dried), and there is a possibility that the overlapping inks may be mixed together or the shape of the formed dots may be lost, resulting in a deterioration in image quality.

  The present invention has been made in view of such problems, and an object of the present invention is to realize a fluid ejection device and a fluid curing method capable of curing a fluid ejected to a medium in a good state. There is.

  A main invention is a nozzle for discharging a fluid having ultraviolet curing properties to a medium, a medium transport unit that transports the medium in a transport direction while facing the nozzle, and a downstream side of the nozzle in the transport direction. And a plurality of ultraviolet light sources for irradiating ultraviolet rays so that at least a part of the medium overlaps the medium.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

  A nozzle for discharging an ultraviolet curable fluid to the medium; a medium conveying unit for conveying the medium in the conveying direction while facing the nozzle; and the medium disposed downstream of the nozzle in the conveying direction. And a plurality of ultraviolet light sources for irradiating ultraviolet rays so that at least a part of them overlaps toward each other.

  According to such a fluid ejection device, since the ultraviolet light source for curing the fluid is disposed downstream in the transport direction from the nozzle that ejects the fluid, the fluid ejected onto the medium as the medium is transported Can be cured. At this time, since the plurality of ultraviolet light sources irradiate the ultraviolet rays so that at least some of them overlap each other toward the medium, it is possible to supply higher energy in the overlapped portion than in the overlapping portion. For this reason, it is possible to harden the fluid more quickly, and it is possible to cure the fluid that is closer to the state immediately after being ejected to the medium, that is, the ejected fluid in a favorable state.

Such a fluid ejection device preferably includes a lens for condensing the ultraviolet rays to be irradiated.
According to such a fluid ejection device, since the ultraviolet rays emitted from the respective ultraviolet light sources are collected by the lens, it is possible to cure the fluid more efficiently by superimposing the collected ultraviolet rays. is there.

In this fluid ejection device, the plurality of ultraviolet light sources emit ultraviolet rays having different peak wavelengths.
According to such a fluid ejecting apparatus, since ultraviolet rays having different peak wavelengths are irradiated in an overlapping manner, a fluid having two or more peak wavelengths as photosensitive characteristics can be efficiently cured simultaneously with the two peak wavelength ultraviolet rays. It is possible to make it.

In this fluid ejection device, the plurality of ultraviolet light sources may emit ultraviolet rays having the same peak wavelength.
According to such a fluid ejecting apparatus, since ultraviolet rays having the same peak wavelength are repeatedly irradiated, more energy is supplied to the fluid by overlappingly irradiating ultraviolet rays having a peak wavelength corresponding to the photosensitive characteristics. It is possible.

In such a fluid ejection device, it is desirable that the position where the ultraviolet rays overlap can be changed.
According to such a fluid ejection device, the position where the ultraviolet rays overlap can be changed, so that the ultraviolet rays emitted from a plurality of ultraviolet light sources can be overlapped at a desired position. For this reason, it is possible to irradiate the ultraviolet rays superimposed at a desired position in accordance with the characteristics of the fluid.

In such a fluid ejection device, it is preferable that the distance between each ultraviolet light source and the position where the ultraviolet rays overlap is equal to each other.
According to such a fluid ejection device, it is possible to irradiate the ultraviolet rays emitted from the respective ultraviolet light sources in a balanced manner.

In such a fluid ejection device, the fluid is preferably ink.
According to such a fluid ejecting apparatus, the ink ejected onto the medium as the medium is transported is irradiated with ultraviolet rays so that at least a part of the ink is superimposed on the medium. Can be formed. Here, the ink includes both water-based ink and oil-based ink.

In addition, at least a part of the ultraviolet ray curable fluid is discharged onto the medium conveyed in the conveying direction, and ultraviolet rays emitted from a plurality of light sources toward the medium from which the fluid is discharged Irradiating so as to overlap with each other.
According to such a fluid curing method, the plurality of ultraviolet light sources are irradiated with ultraviolet rays so that at least a part of the fluid is discharged onto the medium, so that the fluid does not overlap at the portion where the ultraviolet rays overlap. It is possible to supply higher energy than the part to cure the fluid. For this reason, it is possible to harden the fluid more quickly, and it is possible to cure the fluid that is closer to the state immediately after being ejected to the medium, that is, the ejected fluid in a favorable state.

<< Example >>
Hereinafter, a fluid ejection device and a fluid curing method according to an embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, an example of an ink jet printer that ejects ink as a fluid will be described as an example of a fluid ejection device including a plurality of ultraviolet irradiation units for emitting ultraviolet rays.

  FIG. 1 is a diagram schematically showing the overall structure of the ink jet printer 100. As shown in the figure, the ink jet printer 100 includes a drum 110 that supports a sheet 150 as a medium, a recording head 120 that is disposed along the support surface 112 of the drum 110 so as to face the support surface, and an ultraviolet irradiation unit. 200.

  The drum 110 includes a rotation shaft 114 for rotation, and a cylindrical drum main body 110a having a support surface 112 that forms an outer peripheral surface concentrically around the rotation shaft 114 around the rotation shaft 114. , And is provided to be rotatable about a rotation shaft 114. The rotation shaft 114 is provided so as to protrude from the drum main body 110a at the center of a circle that is a cross section of the support surface 112, and is disposed horizontally. The paper 150 is supported on the support surface 112 of the drum main body 110a, and is conveyed when the drum 110 rotates.

  The tip of the rotation shaft 114 is pivotally supported by the support leg 116. With such a structure, the drum 110 rotates about the horizontal rotation shaft 114, and the supported paper 150 can be moved with a certain distance from the recording head 120 and the ultraviolet irradiation unit 200 described later. it can.

  The recording head 120 is supported by a guide shaft 130 that is provided in parallel with the rotation shaft 114 and is stretched over support legs 210 that are disposed at the same interval as the support legs of the rotation shaft 114.

  The recording head 120 includes a plurality of head units 120a, 120b, and 120c. Each of the head units 120a, 120b, and 120c includes a plurality of nozzles 121 and an actuator, and ink supplied from an ink cartridge (not shown). Is discharged from the nozzle 121 toward the paper 150 supported by the drum 110 by an actuator.

  The recording head 120 is fixed to a pair of pulleys 142 and 144 provided on both ends of the guide shaft 130 and a timing belt 140 stretched between the pulleys 142 and 144.

  The recording head 120 electrically controls a motor (not shown) connected to the pulleys 142 and 144 while the nozzle 121 is kept at a constant distance from the support surface 112 of the drum 110, whereby the guide shaft It is configured to reciprocate along 130.

  Different types of ink are supplied to the head units 120a, 120b, and 120c. Thereby, for example, a color image or the like can be formed on the surface of the paper 150. The inks ejected by the head units 120a, 120b, and 120c include, in addition to inks including three primary color materials, a transparent topcoat material that does not include any color materials, and white and black that are highly concealed and have no color. In addition, an undercoat material or the like that forms a background of an image is also included. The ink includes water-based ink and oil-based ink.

The ultraviolet irradiation unit 200 is disposed downstream of the recording head 120 in the rotation direction of the drum 110.
The ultraviolet irradiation unit 200 includes a plurality of light source units 301. In the example of this embodiment, a light source unit group 300 having at least two light source units 301 is provided corresponding to each head unit 120a, 120b, and 120c, and a plurality of light sources included in each light source unit group 300 is provided. The unit 301 is connected to the corresponding head units 120a, 120b, and 120c, and is arranged side by side along the conveyance direction of the paper 150 on the downstream side of the head units 120a, 120b, and 120c.

  FIG. 2 is a schematic diagram for explaining the configuration of one of the plurality of light source units.

  As shown in the drawing, each light source unit 301 includes a unit case 310 having a shape that can be attached to the unit holder 305, a light emitting unit 330 that is housed in the unit case 310 and emits ultraviolet light, and a light emitting unit 330. A lens 312 for concentrating ultraviolet rays emitted from the light emitting unit 330 and disposed on the drum side, and provided so that the ultraviolet rays emitted from the light emitting unit 330 are directed toward the support surface 112 of the drum 110. Yes. Here, it is desirable to use a Selfoc lens as the lens 312.

  As the light emitting unit 330, a semiconductor element such as an LED that emits light in the ultraviolet band is used. In particular, since high-intensity diodes that have been developed in recent years have high output, it is possible to efficiently cure ultraviolet curable ink. On the other hand, an element such as a semiconductor laser has a light emission wavelength determined according to the material and has a limited light emission band. Therefore, it is preferable to select the element in consideration of the curing characteristics of the ultraviolet curable ink to be used. In the ink jet printer 100 of the present embodiment, the light source units 301 use the light source units 301 that emit ultraviolet rays having the same peak wavelength. At this time, it is desirable that the peak wavelength of the ultraviolet light corresponds to the photosensitive characteristics of the ultraviolet curable ink.

  Further, the light source unit 301 is not limited to a light emitting element such as a semiconductor element, and an ultraviolet lamp may be used. In this case, the ultraviolet light generated by the ultraviolet lamp is efficiently irradiated toward the paper 150. A reflector may be provided. Further, as the ultraviolet lamp 340, any of a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low pressure mercury lamp, a high pressure mercury lamp, and the like can be selected. More specifically, commercially available products such as H lamp, D lamp, and V lamp manufactured by Fusion System can be used. This type of ultraviolet lamp can irradiate high-power ultraviolet rays.

  Each light source unit 301 includes four slide shafts 230 arranged in parallel with the rotation shaft 114 and the guide shaft 130, and the slide shafts 230 so that the four slide shafts 230 are arranged in parallel with each other at intervals. And a unit holder 305 that is inserted through two slide shafts 230 adjacent to each other, is held for each light source unit 301, and is slidable along the slide shaft 230. The light source unit slide mechanism 320 is configured to be slidable along the slide shaft 230.

  The support unit 220 on which the four slide shafts are supported is provided on the support leg 210 on which the guide shaft 130 of the recording head 120 is supported. The support part 220 includes a base part 221 provided on the support leg 210, a first link member 222 rotatably connected to the base part 221 and a first slide shaft 230 a, and a first link member 222 and a second one. A second link member 223 rotatably connected by the slide shaft 230b, and a tip member 224 rotatably connected by the second link member 223 and the third slide shaft 230c, The base 221, the first link member 222, the second link member 223, and the tip member 224 are configured to be bendable at a connecting portion by the slide shafts 230 a, 230 b, and 230 c. Further, a fourth slide shaft 230d is provided on the distal end side of the distal end member 224.

  The base portion 221, the first link member 222, and the second link member 223 are formed with arc-shaped elongated holes 220a centering on the slide shafts 230a, 230b, and 230c. The link member 223 and the tip member 224 are provided with screw holes (not shown) into which the fixing screws 225 that respectively penetrate the arc-shaped long holes 220a are screwed. Therefore, the base part 221, the first link member 222, the second link member 223, and the tip member 224 are formed by the angle formed by the base part 221 and the first link member 222, and the first link member 222 and the second link member 223. The angle between the second link member 223 and the tip member 224 can be adjusted, and the adjusted angle can be adjusted by tightening the fixing screw 225 penetrating the arc-shaped elongated hole 220a into the screwing hole. Can be maintained.

  For this reason, each unit holder 305 inserted through the two adjacent slide shafts 230 is adjusted so that the angle formed by the first link member 222, the second link member 223, and the tip member 224 is adjusted. The angle with the holder 305 is adjusted. Thereby, the irradiation position of the ultraviolet light emitted from the light source unit 301 attached to the unit holder 305 is also adjusted, and the fixing screw 225 is tightened and the adjusted state is maintained. For this reason, each light source unit 301 can be adjusted so as to irradiate ultraviolet rays to a desired position in the transport direction of the support surface 112 of the drum 110, and can be fixed and maintained in an adjusted state.

  The unit holder 305 is provided so as to sandwich the light source unit 301 mounted on the mounting portion 305a and the mounting portion 305a to which each light source unit 301 is mounted and extending from both ends of the mounting portion 305a in the slide axis direction. And a pair of extending portions 305b. The pair of extending portions 305b are provided with straight elongated holes 305c that are long in the radial direction of the drum main body 110a, and the light source unit 301 is fixed by penetrating the straight elongated holes 305c. A fixing hole (not shown) into which the screw 450 is screwed is provided. Therefore, by loosening the fixing screw 450, each of the light source units 301 can be individually moved along the longitudinal direction of the linear elongated hole 305c to adjust the distance from the support surface 112 of the drum 110 to an appropriate position. At the same time, it can be fixed and maintained in an adjusted state. It is also possible to adjust the intensity of the ultraviolet rays irradiated to the paper 150 supported by the drum 110 by changing the distance between the light source unit 301 and the drum 110. Further, if the fixing screw 450 is completely removed, each light source unit 301 can be individually removed and replaced.

  The arrangement of each light source unit 301 included in the light source unit group 300 will be described by taking a light source unit group associated with the head unit 120a as an example. FIG. 3 is a diagram illustrating an arrangement of light source unit groups corresponding to the head unit 120a.

  As shown in FIG. 3, the light source unit 301 included in the light source unit group 300 provided so as to correspond to the head unit 120a is set so that at least a part of the ultraviolet rays emitted from the respective light source units 301 are irradiated. Has been. In the example of FIG. 3, the light source unit group 300 corresponding to the head unit 120a includes three light source units 301 along the transport direction on the downstream side of the head unit 120a. Then, ultraviolet rays emitted from the light source unit 301a located in the center in the transport direction are irradiated toward the radial direction of the drum body 110a, and ultraviolet rays emitted from the light source units 301b arranged on the upstream side and the downstream side are emitted. The irradiation area is adjusted so as to be overlapped so as to substantially coincide with the area S irradiated by the central light source unit 301a.

  Each light source unit group 300, which is adjusted so that the ultraviolet rays emitted from the respective light source units 301 a and 301 b arranged in the transport direction overlap each other and is associated with each head unit 120 a, 120 b and 120 c, is attached to the slide shaft 230. The recording heads 120 are arranged side by side and reciprocate along the slide shaft 230 together with the recording head 120 when the recording head 120 is reciprocated along the guide shaft 130.

  The recording operation in the ink jet printer 100 having the above structure is executed as follows.

  The ultraviolet ray curable ink is ejected from the recording head 120 to the paper 150 supported on the support surface 112 of the rotating drum body 110 a and attached to the paper 150. The sheet 150 to which the ultraviolet curable ink is attached faces the ultraviolet irradiation unit 200 according to the rotation of the drum 110 and is exposed to the irradiated ultraviolet rays. As a result, the ultraviolet curable ink adhering to the surface of the paper 150 is cured, and the image formed on the paper 150 is fixed.

  When the drum 110 makes one rotation or more and an image is recorded on the entire length of the sheet 150 in a partial region in the longitudinal direction of the drum 110, the recording head 120 is positioned to face an adjacent region along the guide shaft 130. Move to. At this time, the ultraviolet irradiation unit 200 also moves together. Thus, the moved recording head 120 and ultraviolet irradiation unit 200 perform a recording operation on the moved area. Thereafter, by repeating the recording operation and movement, an image of ultraviolet curable ink is formed on the entire surface of the paper 150. Thus, in the case of the ink jet printer 100, the rotation direction of the drum 110 is the main scanning direction, and the moving direction of the recording head 120 and the ultraviolet irradiation unit 200 is the sub-scanning direction.

  The ultraviolet curable ink that can be used in the ink jet printer 100 as described above is prepared by adding an auxiliary agent such as an antifoaming agent or a polymerization inhibitor to a mixture of a vehicle, a photopolymerization initiator and a pigment. The vehicle is prepared by adjusting the viscosity of an oligomer, monomer or the like having photopolymerization curability with a reactive diluent. Therefore, the solvent is not volatilized for the purpose of curing the ink.

  As the vehicle, monofunctional or polyfunctional polymerizable compounds can be used. More specifically, oligomers (prepolymers) such as polyester acrylate, epoxy acrylate, and urethane acrylate can be exemplified, and these materials can also be used as a reactive diluent for adjusting the viscosity as an ink.

  As the photopolymerization initiator, benzophenone series, benzoin series, acetophenone series, and thioxanthone series are widely used. More specifically, 4-benzoyl-N, N, N-trimethylbenzomethane methanol chloride, 2-hydroxy 3- (4-benzoyl-phenoxy) -N, N, N-trimethylene 1 -N, N-dimethyl N- [2- (1-oxo- 2-propyloxy) ethyl] A quaternary ammonium salt type water-soluble organic substance such as benzene memmonium bromide can be used. This type of photopolymerization initiator has different ultraviolet absorption characteristics, reaction initiation efficiency, yellowing, and the like depending on its composition, so that it is properly used depending on the color of the ink.

  As the polymerization inhibitor, any compound that has radical scavenging ability and inhibits radical polymerization can be used. However, in consideration of ejection suitability and the like in the ink jet recording apparatus, at least one compound selected from hydroquinones, catechols, hindered amines, phenols, phenothiazines, and condensed aromatic ring quinones is preferable.

  Examples of hydroquinones include hydroquinone, hydroquinone monomethyl ether, 1-o-2,3,5-trimethylhydroquinone, 2-tert-butylhydroquinone and the like. Examples of catechols include catechol, 4-methylcatechol, 4-tert-butylcatechol and the like. Examples of hindered amines include compounds having a tetramethylpiperidinyl group.

  Examples of phenols include phenol, butylhydroxytoluene, butylhydroxyanisole, pyrogallol, gallic acid, gallic acid alkyl ester, and the like. Examples of phenothiazines include phenothiazine. Examples of the condensed aromatic ring quinones include naphthoquinone and the like.

  Further, the polymerization inhibitor may be carbon black or inorganic / organic fine particles having a polymerization-inhibiting functional group introduced on the surface. Examples of the polymerization-preventing functional group include a hydroxyphenyl group, a dihydroxyphenyl group, a tetramethylpiperidinyl group, and a condensed aromatic ring.

  The polymer compound as described above may react with oxygen or the like in the atmosphere to change the curing characteristics. Therefore, it is also preferable to cover the surface of the paper 150 while moving from the recording head 120 to the ultraviolet irradiation unit 200 with an inert gas such as nitrogen.

  The ink jet printer 100 according to the present embodiment is configured such that, for example, even the light source units 301 having different wavelengths and outputs can be attached to the unit holder 305 of the ultraviolet irradiation unit 200. Therefore, an image can be cured more efficiently by attaching an appropriate light source unit 301 according to the composition of the ultraviolet curable ink ejected by the recording head 120.

  In addition, when the recording head 120 discharges an undercoat material that preferably has a high curing speed with respect to the ink containing the color material, the irradiation amount is set with some light source units 301, 302, and 303 in accordance with the specifications. Can be increased. In addition, when the recording head 120 discharges a topcoat material that preferably has a low curing speed with respect to ink containing a color material, some of the light source units 301, 302, and 303 are replaced with dummy units that do not have a light source. Alternatively, the ultraviolet irradiation amount may be reduced.

  According to the ink jet printer 100 of the present embodiment, the light source unit group 300 having the light emitting unit 330 as an ultraviolet light source for curing the ultraviolet curable ink is downstream in the transport direction from the nozzle 121 that discharges the ultraviolet curable ink. Therefore, the ultraviolet curable ink discharged onto the paper 150 as the paper 150 is conveyed can be cured by irradiating it with ultraviolet light. At this time, since the plurality of light source units 301 included in the light source unit group 300 are irradiated with ultraviolet rays so that at least a part of the light source units 301 overlaps the sheet 150, a higher energy is supplied in a portion where the ultraviolet rays overlap than in a portion that does not overlap. It is possible. For this reason, the ultraviolet curable ink can be cured more quickly, a state closer to the state immediately after being discharged onto the paper 150, that is, the dot shape formed with the discharged ultraviolet curable ink is maintained, It is possible to cure the ultraviolet curable ink in a good state without mixing different types of superimposed inks.

  In addition, the inkjet printer 100 according to the embodiment includes a plurality of light source units 301 corresponding to one head unit 120a, 120b, and 120c, and irradiates ultraviolet rays emitted from the plurality of light source units 301 in an overlapping manner. is doing. For this reason, when supplying a predetermined amount of energy, it is possible to irradiate with the amount of ultraviolet rays emitted from each light source unit 301 being smaller than when irradiating with one light source unit 301. Therefore, it is possible to suppress the heat generation amount of each light source unit 301 by suppressing the output of each light source unit 301, and it is possible to efficiently irradiate ultraviolet rays by suppressing the heat generation amount.

  Further, since the plurality of light source units 301 are each provided with a lens 312 for collecting the ultraviolet rays to be irradiated, the ultraviolet rays collected by the lens 312 are superposed to cure the ultraviolet curable ink efficiently. It is possible to make it.

  In addition, since the unit holders 305 holding the light source units 301 adjacent to each other in the transport direction are rotatably connected by the slide shaft 230, the irradiation position of the ultraviolet light emitted from each light source unit 301 is moved in the transport direction. It is possible to make it. That is, it is also possible to change the position where the ultraviolet rays emitted from the plurality of light source units 301 provided corresponding to the head units 120a, 120b, and 120c are irradiated. For this reason, it is possible to irradiate ultraviolet rays at an appropriate position according to the characteristics of the ultraviolet curable ink. In this way, by changing the position where the ultraviolet rays are applied in an overlapping manner, it is possible to change the timing of starting the ultraviolet irradiation according to the characteristics of the ultraviolet curable ink.

  Further, when the position and inclination of each light source unit 301 are set so that the distance between the two light source units 301 adjacent in the transport direction and the position where the ultraviolet rays overlap on the support surface 112 is equal to each other, the adjacent light source units 301 are arranged. It is possible to irradiate the ultraviolet rays emitted from each of the light source with a good balance, and the output level between the light source units 301 can be easily adjusted.

By the way, although the ultraviolet light-sensitive property of the ultraviolet curable ink varies depending on the composition of the vehicle, the ultraviolet light becomes a color material depending on factors other than the composition of the vehicle, the color of the color material contained in the ultraviolet curable ink, and the surface properties. It can be absorbed or reflected to affect the cure rate of the vehicle.

  For example, when the concentration of the coloring material is high, the transmittance of ultraviolet rays may be reduced, and the vehicle curing rate may be slow. In addition, when the concentration of the color material in the ultraviolet curable ink is low, the ultraviolet light may pass through the ultraviolet curable ink without being scattered, and the curing speed may be slow. As described above, the ultraviolet curable ink may have complicated photosensitive characteristics with respect to the wavelength distribution of the irradiated ultraviolet rays due to various factors.

  FIG. 4 is a graph showing an example of the photosensitive characteristic of the ultraviolet curable ink. FIG. 5 is a graph showing the wavelength characteristics of ultraviolet rays emitted from one of the plurality of light source units. FIG. 6 is a graph showing the wavelength characteristics of ultraviolet rays irradiated by other light source units among the plurality of light source units.

  Since the inkjet printer 100 includes the plurality of light source units 301 having the same peak wavelength of the ultraviolet rays to be irradiated, the ultraviolet rays having the same peak wavelength corresponding to the photosensitive characteristics of the ultraviolet curable ink are overlapped and irradiated. Although it is possible to supply more energy while suppressing heat generation, the peak wavelengths of the ultraviolet rays emitted from the plurality of light source units 301 are not necessarily the same. For example, when an ultraviolet curable ink having two peaks on the short wavelength side and the long wavelength side as shown in FIG. 4 is used as the ultraviolet curable ink, ultraviolet rays having different peak wavelengths are used. It is desirable to include a light source unit 301 that emits light.

  For example, a light emitting element such as an LED as the light emitting unit 330 included in the light source unit 301 illustrated in FIG. 5 has a large peak in a specific wavelength band. For this reason, when the ultraviolet ray curable ink having the photosensitive characteristics shown in FIG. 4 is irradiated with the ultraviolet rays generated by the light source unit 301, the curing speed becomes low. Further, a light emitting element such as an LED as the light emitting unit 330 having the light source unit 301 shown in FIG. 6 has a large peak in a band different from that of the light source unit 301 shown in FIG.

  Therefore, the inkjet printer 100 according to another embodiment includes a plurality of light source units 301 corresponding to the head units 120a, 120b, and 120c, and each light source unit 301 is irradiated with ultraviolet rays having different peak wavelengths. ing. In this manner, by irradiating a plurality of ultraviolet rays having different peak wavelengths, it is possible to irradiate the ultraviolet rays having a band distribution corresponding to the photosensitive characteristics of the ultraviolet curable ink shown in FIG. Therefore, an ultraviolet curable ink having photosensitive characteristics including two peaks can be quickly and efficiently cured.

 FIG. 7 is a graph showing an example of wavelength characteristics of the ultraviolet lamp. When using an ultraviolet curable ink having photosensitive characteristics including three or more different peak wavelengths, it is desirable to use an ultraviolet lamp having characteristics including many peaks in a relatively wide range as shown in FIG. .

  Thus, the ultraviolet irradiation unit 200 is equipped with a plurality of arbitrarily selected light source units 301 corresponding to one head unit 120a, 120b, and 120c, so that ultraviolet curable ink to be irradiated with ultraviolet rays can be obtained. It is possible to irradiate ultraviolet rays having various band characteristics according to complicated photosensitive characteristics. As described above, since the plurality of light source units 301 emit ultraviolet rays having different peak wavelengths, the ultraviolet rays having different peak wavelengths are radiated in an overlapping manner, and therefore, ultraviolet curing having two or more peak wavelengths as photosensitive characteristics. The mold ink can be efficiently cured with ultraviolet rays having two or more peak wavelengths at the same time.

<< Other Examples >>
The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

  In the above embodiment, a plurality of light source units 301 arranged side by side in the transport direction by the slide shaft 230, the support unit 220, and the unit holder 305 constituting the light source unit slide mechanism 320 are emitted from each light source unit. However, the mechanism for changing the angle of the light source units 301 is not limited to this. For example, the light source unit may be configured such that a frame is provided on the opposite side of the drum, each light source unit is attached to the frame via a bendable portion that can adjust the angle, and the angle can be adjusted for each light source unit.

  Further, the light source unit may be configured to include a cooling fan in order to suppress the heat generation of the light source unit.

  In the above-described embodiment, the example in which each light source unit 301 includes the lens 312 to collect light has been described. However, the lens does not necessarily have to be provided. Further, the light source unit may be provided with a plurality of light emitting units adjacent to each other, and the ultraviolet rays irradiated without condensing may overlap each other. Moreover, in the said embodiment, although the example overlapped so that the area | region irradiated with the ultraviolet-ray emitted from two or more light emission parts substantially matched was demonstrated, the area | region which the ultraviolet-ray emitted from each light emission part irradiates As long as at least a part of them overlap.

  In the above embodiment, an example in which two or three light source units are provided corresponding to the head units has been described. However, the number of light source units for one head unit is not limited to this. In addition, four or more unit holders 305 to which light source units can be attached are provided for one head unit, and a necessary number of light source units are provided according to the characteristics of the ultraviolet curable ink used. Also good. At this time, if the number of necessary light source units is less than the number of unit holders provided and a unit holder without a light source unit is generated, a gap is formed in a portion facing the drum, The laminar flow formed on the surface of the drum may be disturbed by the airflow due to the movement of the cooling fan, the recording head, and the light source unit described above. For this reason, it is desirable to attach a dummy unit that does not generate ultraviolet rays to the unit holder to which the light source unit is not attached, and to flatten the surface side of the ultraviolet irradiation unit facing the drum.

  In the above embodiment, the ink jet printer 100 is exemplified as the liquid ejecting apparatus. However, other liquids (such as a liquid material in which functional material particles are dispersed or a fluid such as a gel) are ejected. It can also be embodied in a liquid discharge device that discharges. For example, a liquid material ejecting apparatus that discharges a liquid material in the form of dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays, and biochip manufacturing It may be a liquid ejecting apparatus for ejecting a bio-organic substance used in the above, or a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette. In addition, a transparent resin liquid such as UV curable resin is used to form a liquid ejection device that ejects lubricating oil pinpoint to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid discharge device that discharges a liquid onto the substrate, a liquid discharge device that discharges an etching solution such as acid or alkali to etch the substrate, and a fluid discharge device that discharges gel. The present invention can be applied to any one of these discharge devices.

1 is a diagram schematically showing the overall structure of an ink jet printer 100. FIG. It is a schematic diagram for demonstrating the structure of one light source unit among several light source units. FIG. 4 is a diagram illustrating an arrangement of light source unit groups corresponding to a head unit Z. It is a graph which shows an example of the photosensitive characteristic of an ultraviolet curable ink. It is a graph which shows the wavelength characteristic of the ultraviolet-ray which one light source unit irradiates among several light source units. It is a graph which shows the wavelength characteristic of the ultraviolet-ray which other light source units irradiate among several light source units. It is a graph which shows an example of the wavelength characteristic of an ultraviolet lamp.

Explanation of symbols

100 Inkjet printer, 110 drum, 110a drum body,
112 support surface, 120 recording head, 120a head unit, 121 nozzles,
150 paper, 200 UV irradiation unit, 300 light source unit group,
301 light source unit, 301a light source unit, 301b light source unit,
305 unit holder, 305a mounting part, 305b extension part, 312 lens,
320 light source unit slide mechanism, 330 light emitting unit, 340 ultraviolet lamp,
S Area where ultraviolet rays overlap

Claims (8)

A nozzle for discharging an ultraviolet curable fluid to the medium;
A medium transport unit that transports the medium in the transport direction while facing the nozzle;
A plurality of ultraviolet light sources disposed on the downstream side of the nozzle in the transport direction and for irradiating the ultraviolet rays so that at least a part of the ultraviolet light is overlapped toward the medium;
A fluid ejection device comprising: The fluid ejection device according to claim 1,
A fluid ejection device comprising a lens for condensing the ultraviolet rays to be irradiated. The fluid ejection device according to claim 1 or 2,
The fluid discharge device, wherein the plurality of ultraviolet light sources emit ultraviolet rays having different peak wavelengths. The fluid ejection device according to claim 1 or 2,
The fluid discharge device, wherein the plurality of ultraviolet light sources emit ultraviolet rays having the same peak wavelength. A fluid ejection device according to any one of claims 1 to 4,
The fluid discharge device according to claim 1, wherein a position where the ultraviolet rays overlap can be changed. The fluid ejection device according to claim 4 or 5, wherein
The distance between each ultraviolet light source and the position where the ultraviolet rays overlap is equal to each other. The fluid ejection device according to any one of claims 1 to 6,
The fluid ejection apparatus, wherein the fluid is ink. Discharging an ultraviolet curable fluid to a medium conveyed in the conveying direction;
Irradiating ultraviolet rays emitted from a plurality of light sources toward the medium from which the fluid is discharged so that at least a part of them overlaps;
A fluid curing method comprising:

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