Liquid ejecting apparatus and ultraviolet irradiation apparatus

Abstract

The invention relates to a liquid ejecting apparatus and an ultraviolet irradiation apparatus. A load applied to a motor for moving a carriage is suppressed. The liquid ejecting apparatus includes: a liquid ejecting unit that ejects a liquid cured by irradiation of ultraviolet light onto a medium; an irradiation unit that irradiates the liquid ejected onto the medium with ultraviolet rays; a carriage on which the liquid discharge unit and the irradiation unit are mounted and which moves on the medium; and a motor for moving the carriage. The irradiation unit is provided with: a substrate; and an ultraviolet light source that is provided on the substrate and emits ultraviolet light, the substrate having an aluminum base material.

Description

Technical Field

[0001] The present invention relates to a liquid ejecting device and an ultraviolet irradiation device. Background Art

[0002] Liquid ejection devices are known that eject ultraviolet curable ink (an example of "liquid"), which is cured by ultraviolet irradiation, onto a medium. For example, Patent Document 1 discloses a liquid ejection device comprising: a liquid ejection unit for ejecting ultraviolet curable ink onto a medium; an irradiation unit for irradiating the liquid ejected onto the medium with ultraviolet light; a carriage for carrying the liquid ejection unit and the irradiation unit and moving over the medium; and a motor for moving the carriage.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-017731

[0004] However, according to the conventional technology, since the irradiation unit is mounted on the carriage in addition to the liquid ejection unit, there is a problem in that the load applied to the motor for moving the carriage increases. Summary of the Invention

[0005] In order to solve the above problems, the liquid ejection device involved in the present invention is characterized in that it comprises: a liquid ejection unit, which ejects liquid solidified by ultraviolet irradiation to a medium; an irradiation unit, which irradiates ultraviolet light on the liquid ejected onto the medium; a slide, which carries the liquid ejection unit and the irradiation unit and moves on the medium; and a motor, which is used to move the slide, the irradiation unit comprises: a substrate; and an ultraviolet light source, which is arranged on the substrate and emits ultraviolet light, and the substrate has an aluminum base material.

[0006] In addition, the ultraviolet irradiation device involved in the present invention is characterized in that it is arranged in a liquid ejecting device, and the liquid ejecting device comprises: a liquid ejecting unit that ejects liquid solidified by ultraviolet irradiation onto a medium; a slide that carries the liquid ejecting unit and moves on the medium; and a motor for moving the slide, the ultraviolet irradiation device is mounted on the slide and irradiates ultraviolet light on the liquid ejected onto the medium, and the ultraviolet irradiation device comprises: a substrate; and an ultraviolet light source that is arranged on the substrate and emits ultraviolet light, and the substrate has an aluminum base material. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a block diagram showing an example of the configuration of the inkjet printer 1 according to the first embodiment of the present invention.

[0008] Figure 2 This is a perspective view showing an example of a schematic internal structure of the inkjet printer 1 .

[0009] Figure 3 It is a cross-sectional view for explaining an example of the structure of the ejection portion D[m].

[0010] Figure 4 It is a plan view showing an example of arrangement of objects mounted on the carriage 110 .

[0011] Figure 5 It is a cross-sectional view showing an example of the structure of the ultraviolet irradiation unit 5 .

[0012] Figure 6 1 is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5 and the ultraviolet light source E.

[0013] Figure 7 1 is a block diagram showing an example of the configuration of the temperature detection integrated circuit 7 .

[0014] Figure 8 1 is an explanatory diagram showing an example of the radiation flux characteristics of the ultraviolet light source E.

[0015] Figure 9 This is a diagram showing the premise of illumination simulation.

[0016] Figure 10 3 is a diagram showing the results of the first illumination simulation.

[0017] Figure 11 It is an explanatory diagram for showing an outline of a conventional example.

[0018] Figure 12 is a graph showing the thermal conductivity and specific gravity of various metals.

[0019] Figure 13 It is a cross-sectional view showing an example of the structure of the ultraviolet irradiation unit 5B according to the second embodiment of the present invention.

[0020] Figure 14 This is a diagram showing the premise of illumination simulation.

[0021] Figure 15 2 is a diagram showing the results of the second illumination simulation.

[0022] Figure 16 3 is a diagram showing the results of the third illumination simulation.

[0023] Figure 17 3 is a diagram showing the results of the fourth illumination simulation.

[0024] Figure 18 3 is a diagram showing the results of the fifth illumination simulation.

[0025] Figure 19 2 is a diagram showing the results of the sixth illumination simulation.

[0026] Figure 20 2 is a diagram showing the results of the seventh illumination simulation.

[0027] Figure 21 2 is a diagram showing the results of the eighth illumination simulation.

[0028] Figure 22 1 and 2 are diagrams showing the results of the second to eighth illumination simulations.

[0029] Figure 23 It is a cross-sectional view showing an example of the structure of an ultraviolet irradiation unit 5C according to the third embodiment of the present invention.

[0030] Figure 24 This is a diagram showing the premise of illumination simulation.

[0031] Figure 25 2 is a diagram showing the results of the ninth illumination simulation.

[0032] Figure 26 2 is a diagram showing the results of the tenth illumination simulation.

[0033] Figure 27 This is a cross-sectional view showing an example of the configuration of an ultraviolet light source E according to Modification 1 of the present invention.

[0034] Figure 28 1 is a cross-sectional view showing an example of the directional characteristics of the ultraviolet light source E.

[0035] Description of Reference Numerals

[0036] 1…Inkjet printer, 2…Control unit, 3…Liquid ejection unit, 4…Drive signal generation unit, 5…Ultraviolet irradiation unit, 6…Ultraviolet light source module, 7…Temperature detection integrated circuit, 9…Conveyor unit, 50…Casing, 51…Substrate, 52…Heat sink, 53…Grease, 54…Gold plating, 61…Wall, 62…Wall, 71…Semiconductor temperature sensor, 72…Signal conversion circuit, 81…Light emitting unit, 82…Lens, 83…Encapsulation, 84…Connecting wiring, 91…Slide transport motor, 92…Media transport motor, 95…Platen, 110…Slide, 501…Frame, 502…Cover, 511…Base material, 512…Insulating layer, 513…Resist, 514…Wiring, 601…Wall, 602…Wall, D…Ejector, E…Ultraviolet light source. DETAILED DESCRIPTION

[0037] The following describes the embodiment of the present invention with reference to the accompanying drawings. However, the dimensions and scales of the various parts in the drawings may differ from the actual dimensions and scales. Furthermore, the embodiments described below are preferred specific examples of the present invention and are therefore subject to various technically preferred limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0038] A. First Implementation>>

[0039] In the first embodiment, the liquid ejecting apparatus is described by taking as an example an inkjet printer 1 that ejects ink and forms an image on recording paper PP.

[0040] A.1. Overview of inkjet printers

[0041] Below, refer to Figures 1 to 4 An example of the structure of the inkjet printer 1 according to the first embodiment will be described.

[0042] Figure 1 This is a functional block diagram showing an example of the configuration of the inkjet printer 1 .

[0043] like Figure 1 As shown, print data Img indicating an image to be formed by the inkjet printer 1 is supplied from a host computer such as a personal computer or a digital camera to the inkjet printer 1. The inkjet printer 1 executes a print process to form the image indicated by the print data Img supplied from the host computer on recording paper PP.

[0044] like Figure 1 As shown, the inkjet printer 1 includes: a control unit 2 for controlling the various parts of the inkjet printer 1; a liquid ejection unit 3 provided with an ejection portion D for ejecting ink onto the recording paper PP; a drive signal generating unit 4 for generating a drive signal Com for driving the ejection portion D; an ultraviolet irradiation unit 5 for irradiating ultraviolet rays on the ink ejected onto the recording paper PP; and a conveying unit 9 for conveying the liquid ejection unit 3 and the recording paper PP.

[0045] Furthermore, in the first embodiment, it is assumed that the ink ejected from the liquid ejection unit 3 is ultraviolet curing ink that is cured by irradiation with ultraviolet rays.

[0046] In addition, in the first embodiment, the inkjet printer 1 is an example of a "liquid ejecting device", the ultraviolet curing ink is an example of a "liquid", the recording paper PP is an example of a "medium", and the ultraviolet irradiation unit 5 is an example of an "irradiation unit" and an "ultraviolet irradiation device".

[0047] In the first embodiment, it is assumed that the inkjet printer 1 includes one or more liquid ejecting units 3 and one or more drive signal generating units 4 corresponding one to one with the one or more liquid ejecting units 3. Specifically, in the first embodiment, it is assumed that the inkjet printer 1 includes four liquid ejecting units 3 and four drive signal generating units 4 corresponding one to one with the four liquid ejecting units 3. However, for the sake of convenience, Figure 1 As shown, the description will sometimes be made focusing on one of the four liquid ejecting units 3 and one of the four drive signal generating units 4 provided corresponding to the one liquid ejecting unit 3 .

[0048] The control unit 2 is configured to include one or more CPUs (Central Processing Units). However, the control unit 2 may also include a programmable logic device such as an FPGA (Field-Programmable Gate Array) in place of or in addition to a CPU. Furthermore, the control unit 2 includes memory. The memory may include one or both of volatile memory such as RAM (Random Access Memory), non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable ROM).

[0049] The control unit 2 generates signals for controlling the operation of various components of the inkjet printer 1 , such as a designation signal SI, a waveform designation signal dCom, a light source control signal SL, a carriage transport control signal SK, and a medium transport control signal SB.

[0050] Here, the waveform designation signal dCom is a digital signal that specifies the waveform of the drive signal Com. The drive signal Com is an analog signal for driving the ejection unit D. The designation signal SI is a digital signal that specifies the type of operation of the ejection unit D. Specifically, the designation signal SI specifies the type of operation of the ejection unit D, such as whether or not ink is ejected from the ejection unit D, by specifying whether the drive signal Com is supplied to the ejection unit D. The light source control signal SL is a signal for controlling the ultraviolet irradiation unit 5. The carriage transport control signal SK and the medium transport control signal SB are signals for controlling the transport unit 9.

[0051] When executing a print process, the control unit 2 generates signals such as a designation signal SI for controlling the liquid ejection unit 3 based on the print data Img. Furthermore, when executing a print process, the control unit 2 generates signals such as a waveform designation signal dCom for controlling the drive signal generation unit 4. Furthermore, when executing a print process, the control unit 2 generates signals such as a carriage transport control signal SK and a medium transport control signal SB for controlling the transport unit 9. Thus, the control unit 2 controls various components of the inkjet printer 1 during the print process, controlling the transport unit 9 so as to move the liquid ejection unit 3 and the recording paper PP, adjusting the presence or absence of ink ejection from the ejection portion D and the timing of ink ejection, and forming an image corresponding to the print data Img on the recording paper PP.

[0052] like Figure 1 As shown, the liquid ejection unit 3 includes a supply circuit 31 and a liquid ejection head 32 .

[0053] The liquid ejection head 32 includes M ejection units D. Here, the value M is a natural number satisfying "M ≥ 1." Hereinafter, the mth ejection unit D among the M ejection units D provided in the liquid ejection head 32 may be referred to as ejection unit D[m]. Herein, the variable m is a natural number satisfying "1 ≤ m ≤ M." Hereinafter, when a component or signal of the inkjet printer 1 corresponds to an ejection unit D[m] among the M ejection units D, the subscript "m" may be added to the reference numeral representing the component or signal.

[0054] The supply circuit 31 switches whether to supply the drive signal Com to the ejection portion D[m] based on the designation signal SI. Hereinafter, the drive signal Com supplied to the ejection portion D[m] among the drive signals Com may be referred to as the supply drive signal Vin[m].

[0055] like Figure 1 As shown, the ultraviolet irradiation unit 5 includes an ultraviolet light source module 6 and a temperature detection integrated circuit 7 .

[0056] The ultraviolet light source module 6 includes a plurality of ultraviolet light sources E that emit ultraviolet rays, and irradiates the recording paper PP transported by the transport unit 9 with ultraviolet rays.

[0057] Furthermore, in the first embodiment, it is assumed that the ultraviolet light emitted by the ultraviolet light source E has a wavelength of 250 nm to 410 nm. Therefore, compared to a scheme in which ultraviolet light having a wavelength of 100 nm to 230 nm is irradiated from the ultraviolet light source E, the possibility of the ultraviolet light emitted from the ultraviolet light source E reacting with oxygen in the air and generating ozone can be reduced.

[0058] Although not shown in the figure, the inkjet printer 1 according to the first embodiment includes a rubber component (an example of a "specific member"). Rubber components degrade when exposed to ozone. However, in the first embodiment, as described above, since the ultraviolet light source E emits ultraviolet light with a wavelength of 250 nm to 410 nm, degradation of the rubber component can be suppressed compared to a solution in which the ultraviolet light source E emits ultraviolet light with a wavelength of 100 nm to 230 nm.

[0059] The temperature detection integrated circuit 7 detects the temperature inside the ultraviolet irradiation unit 5 and outputs a temperature detection signal DT as a digital signal indicating a value based on the detected temperature. The control unit 2 generates a light source control signal SL based on the temperature detection signal DT output by the temperature detection integrated circuit 7.

[0060] Furthermore, in the first embodiment, the light source control signal SL is a signal that specifies the intensity of ultraviolet light emitted from the ultraviolet light source E. More specifically, in the first embodiment, the ultraviolet light source module 6 causes each ultraviolet light source E to emit ultraviolet light according to the intensity indicated by the light source control signal SL. However, the present invention is not limited to this embodiment. The light source control signal SL may also be a signal that specifies whether the ultraviolet light source E is turned on or off. In this case, the ultraviolet light source module 6 turns on the ultraviolet light source E when the light source control signal SL specifies on, and turns off the ultraviolet light source E when the light source control signal SL specifies off.

[0061] like Figure 1 As shown, the transport unit 9 includes a carriage transport motor 91 and a medium transport motor 92 .

[0062] The carriage transport motor 91 transports a carriage 110 described later based on a carriage transport control signal SK.

[0063] The medium conveying motor 92 conveys the recording paper PP based on the medium conveying control signal SB.

[0064] Figure 2 This is a perspective view showing an example of a schematic internal structure of the inkjet printer 1 .

[0065] like Figure 2As shown, in the first embodiment, the inkjet printer 1 is assumed to be a serial printer. Specifically, when executing a print process, the inkjet printer 1 simultaneously transports the recording paper PP in the X1 direction while moving the liquid ejection unit 3 in the Y1 direction intersecting the X1 direction, ejecting ink from the liquid ejection unit 3. This forms an image corresponding to the print data Img on the recording paper PP. Furthermore, when executing a print process, the inkjet printer 1 simultaneously moves the ultraviolet irradiation unit 5 in the Y1 direction while irradiating the recording paper PP with ultraviolet light, thereby curing the ink ejected onto the recording paper PP.

[0066] Furthermore, in the first embodiment, when the liquid ejection unit 3 is moved to the end in the Y1 direction, the inkjet printer 1 does not eject ink from the liquid ejection unit 3, but moves the liquid ejection unit 3 in the Y2 direction, which is opposite to the Y1 direction. Furthermore, in the first embodiment, the inkjet printer 1 does not irradiate ultraviolet rays from the ultraviolet irradiation unit 5, but moves the ultraviolet irradiation unit 5 in the Y2 direction.

[0067] Hereinafter, the X1 direction and the X2 direction, which is the opposite direction thereof, will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and the Y2 direction, which is the opposite direction thereof, will be collectively referred to as the "Y-axis direction," and the Z1 direction intersecting the X-axis direction and the Y-axis direction and the Z2 direction, which is the opposite direction thereof, will be collectively referred to as the "Z-axis direction." In the first embodiment, as an example, the description will be made assuming that the X-axis direction, the Y-axis direction, and the Z-axis direction are mutually orthogonal. However, the present invention is not limited to such a solution. The X-axis direction, the Y-axis direction, and the Z-axis direction only need to intersect with each other. In addition, in the first embodiment, the Z1 direction is the direction in which ink is ejected from the ejection portion D.

[0068] like Figure 2 As shown, the inkjet printer 1 according to the first embodiment includes a housing 100 and a carriage 110 that is reciprocally movable in the Y-axis direction within the housing 100. The carriage 110 carries four liquid ejection units 3 and an ultraviolet irradiation unit 5. Specifically, the carriage 110 carries the four liquid ejection units 3 and the ultraviolet irradiation unit 5 so that the four liquid ejection units 3 are positioned in the Y1 direction when viewed from the ultraviolet irradiation unit 5.

[0069] In the first embodiment, as Figure 2As shown, it is assumed that the carriage 110 carries four ink cartridges 120 corresponding one-to-one to the four colors of ink: cyan, magenta, yellow, and black. Furthermore, in the first embodiment, as described above, it is assumed that the carriage 110 carries four liquid ejection units 3 corresponding one-to-one to the four ink cartridges 120. Each ejection portion D[m] receives a supply of ink from the ink cartridge 120 corresponding to the liquid ejection unit 3 in which the ejection portion D[m] is located. Thus, each ejection portion D[m] can be filled with the supplied ink and eject the ink filled in the ejection portion D[m] from the nozzle N located in the ejection portion D[m]. Alternatively, the ink cartridges 120 can be located outside the carriage 110.

[0070] Furthermore, as described above, the inkjet printer 1 according to the first embodiment includes the transport unit 9. Figure 2 As shown, the transport unit 9 includes a carriage transport motor 91 for reciprocating the carriage 110 in the Y-axis direction; a carriage guide shaft 96 for reciprocatingly supporting the carriage 110 in the Y-axis direction; a belt 97 for transporting the carriage 110 in the Y-axis direction in response to the carriage transport motor 91; a medium transport motor 92 for transporting the recording paper PP in the X1 direction; a medium transport mechanism 93 that rotates in response to the drive of the medium transport motor 92 to transport the recording paper PP in the X1 direction; and a platen 95 disposed in the Z1 direction relative to the carriage 110. Therefore, when the transport unit 9 is performing printing, the carriage transport motor 91 reciprocates the liquid ejection unit 3 along with the carriage 110 in the Y-axis direction along the carriage guide shaft 96, and the media transport motor 92 transports the recording paper PP on the platen 95 in the X1 direction. This changes the relative position of the recording paper PP with respect to the liquid ejection unit 3, enabling ink to be deposited on the entire recording paper PP.

[0071] In addition, in the first embodiment, the carriage transport motor 91 is an example of a “motor”.

[0072] Figure 3 2 is a schematic partial cross-sectional view of the liquid ejecting head 32 cut so as to include the ejection portion D[m].

[0073] like Figure 3As shown, the ejection unit D[m] includes a piezoelectric element PZ[m], a cavity CV filled with ink, a nozzle N connected to the cavity CV, and a vibration plate 321. The ejection unit D[m] is driven by a drive signal Vin[m] supplied to the piezoelectric element PZ[m], causing the ink in the cavity CV to be ejected from the nozzle N. The cavity CV is a space defined by a cavity plate 324, a nozzle plate 323 on which the nozzle N is formed, and the vibration plate 321. The cavity CV is connected to the reservoir 325 via an ink supply port 326. The reservoir 325 is connected to the ink cartridge 120 corresponding to the ejection unit D[m] via an ink inlet 327. The piezoelectric element PZ[m] includes an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric body Zm[m] disposed between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to a power supply line Ld set to a predetermined potential VBS. Furthermore, when a drive signal Vin[m] is supplied to the upper electrode Zu[m] and a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] displaces in the Z1 and Z2 directions in accordance with the applied voltage, resulting in the piezoelectric element PZ[m] vibrating. The lower electrode Zd[m] is connected to the vibration plate 321. Therefore, when the piezoelectric element PZ[m] is driven to vibrate by the drive signal Vin[m], the vibration plate 321 also vibrates. The vibration of the vibration plate 321 then changes the volume of the cavity CV and the pressure within the cavity CV, causing the ink filled in the cavity CV to be ejected from the nozzle N.

[0074] Figure 4 This is a plan view showing an example of the arrangement of the objects mounted on the carriage 110 when the carriage 110 is viewed in plan in the Z2 direction.

[0075] like Figure 4 As illustrated, the carriage 110 is equipped with the ultraviolet irradiation unit 5 and four liquid ejection units 3 arranged in the Y1 direction. Specifically, in the first embodiment, the carriage 110 is equipped with the ultraviolet irradiation unit 5 and four liquid ejection units 3 so that the four liquid ejection units 3 are positioned in the Y1 direction when viewed from the ultraviolet irradiation unit 5. Therefore, in the first embodiment, when the inkjet printer 1 is executing a print process, the ultraviolet irradiation unit 5 can irradiate the ink ejected onto the recording paper PP with ultraviolet rays while moving in the Y1 direction, thereby curing the ink, immediately after the ink ejected by the liquid ejection unit 3 while moving in the Y1 direction has adhered to the recording paper PP.

[0076] like Figure 4As illustrated, each liquid ejection unit 3 mounted on the carriage 110 is provided with a nozzle row NL. Here, a nozzle row NL refers to a plurality of nozzles N arranged so as to extend in a row in a predetermined direction. In the first embodiment, a case where each nozzle row NL is composed of M nozzles N arranged so as to extend in the X-axis direction is assumed as an example.

[0077] As described above, the ultraviolet irradiation unit 5 includes an ultraviolet light source module 6 including a plurality of ultraviolet light sources E and a temperature detection integrated circuit 7. In the first embodiment, as an example, the ultraviolet light source module 6 is disposed between the temperature detection integrated circuit 7 and the liquid ejection unit 3 in the carriage 110. However, the present invention is not limited to this embodiment. For example, the temperature detection integrated circuit 7 may also be disposed between the ultraviolet light source module 6 and the liquid ejection unit 3 in the carriage 110.

[0078] As described above, the ultraviolet light source module 6 includes a plurality of ultraviolet light sources E. In the first embodiment, it is assumed that the ultraviolet light source module 6 has NX × NY ultraviolet light sources E arranged in a matrix of NX rows × NY columns in the X1 direction and NY columns in the Y1 direction. Here, the value NX is a natural number satisfying "NX ≥ 1." Furthermore, the value NY is a natural number satisfying "NY ≥ 1." In the first embodiment, the value NY is assumed to be "4" as an example.

[0079] In addition, hereinafter, the interval between two adjacent ultraviolet light sources E in the X1 direction is referred to as the interval dLX, and the interval between two adjacent ultraviolet light sources E in the Y1 direction is referred to as the interval dLY. In the first embodiment, as an example, it is assumed that the interval dLX is less than the interval dLY. That is, in the first embodiment, as an example, it is assumed that the arrangement interval in the X-axis direction of the plurality of ultraviolet light sources E arranged in a matrix is ​​less than the arrangement interval in the Y-axis direction. In addition, the "interval between two adjacent ultraviolet light sources E" may refer to the distance between the center of one ultraviolet light source E and the center of the other ultraviolet light source E when looking down at the carriage 110 in the Z2 direction, or it may refer to the shortest distance between one ultraviolet light source E and the other ultraviolet light source E.

[0080] like Figure 4As illustrated, in the first embodiment, the temperature detection integrated circuit 7 is positioned in the middle of the ultraviolet irradiation unit 5 in the X-axis direction. More specifically, in the first embodiment, the temperature detection integrated circuit 7 is positioned at a position approximately the same as the distance in the X-axis direction from the end in the X1 direction of the arrangement area of ​​the multiple ultraviolet light sources E of the ultraviolet irradiation unit 5 and the distance in the X-axis direction from the end in the X2 direction of the arrangement area of ​​the multiple ultraviolet light sources E of the ultraviolet irradiation unit 5. Here, "approximately the same" not only means completely identical, but also includes situations that are considered the same if errors are taken into account. For example, situations where the same design differs due to manufacturing errors, and situations where the same specifications differ due to errors caused by noise, etc. In the first embodiment, "approximately the same" is a concept that includes situations that are considered the same if errors of approximately 10% are taken into account.

[0081] A.2. Overview of the Ultraviolet Irradiation Unit 5

[0082] Below, refer to Figure 5 and Figure 6 , the structure of the ultraviolet irradiation unit 5 is described.

[0083] Figure 5 This is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5 when the ultraviolet irradiation unit 5 is cut along a plane whose normal direction is the X-axis direction.

[0084] like Figure 5 As shown, the ultraviolet irradiation unit 5 includes an ultraviolet light source module 6 including a plurality of ultraviolet light sources E and a temperature detection integrated circuit 7 , as well as a substrate 51 , a heat sink 52 , and a housing 50 .

[0085] The substrate 51 is a flat plate member extending with the Z-axis direction as its normal direction, and has two surfaces with the Z-axis direction as its normal direction: a surface 51z1 facing the Z1 direction and a surface 51z2 facing the Z2 direction.

[0086] like Figure 5 As shown, a plurality of ultraviolet light sources E and a temperature detection integrated circuit 7 are provided on the surface 51z1. In addition, a housing 50 is provided on the surface 51z1 so as to cover the plurality of ultraviolet light sources E and the temperature detection integrated circuit 7.

[0087] The housing 50 includes a plurality of ultraviolet light sources E, a frame 501 covering the temperature detection integrated circuit 7 , and a cover 502 provided in the Z1 direction when viewed from the plurality of ultraviolet light sources E.

[0088] The frame 501 is formed of metal and prevents ink ejected from the liquid ejection unit 3 from adhering to electronic components such as the ultraviolet light source E and the temperature detection integrated circuit 7 provided on the substrate 51, and various wiring provided on the substrate 51. However, the frame 501 may be formed of a material other than metal, such as resin.

[0089] The cover plate 502 is formed of ultraviolet-transmissive glass to prevent ink ejected from the liquid ejection unit 3 from adhering to the ultraviolet light source E and various wirings provided on the substrate 51. However, the cover plate 502 may be formed of a material other than glass, such as a transparent resin that transmits ultraviolet light.

[0090] Furthermore, in the first embodiment, the cover plate 502 is provided so as to be both removable and attachable to the frame 501. Specifically, in the first embodiment, the cover plate 502 can be replaced from the ultraviolet irradiation unit 5 without removing the ultraviolet irradiation unit 5 from the inkjet printer 1, while the ultraviolet irradiation unit 5 remains installed. Therefore, according to the first embodiment, in situations such as when ink adheres to the cover plate 502 and the intensity of ultraviolet rays irradiated onto the recording paper PP from the ultraviolet light source E decreases, the cover plate 502 can be easily replaced, thereby improving the maintainability of the ultraviolet irradiation unit 5 compared to solutions in which the cover plate 502 cannot be replaced.

[0091] like Figure 5 As shown, on surface 51z1, a wall portion 61 is provided between the multiple ultraviolet light sources E and the liquid ejection unit 3. Furthermore, a wall portion 62 is provided between the multiple ultraviolet light sources E and the temperature detection integrated circuit 7. Furthermore, in the first embodiment, it is assumed that the wall surface 601 of the wall portion 61 facing the ultraviolet light sources E and the wall surface 602 of the wall portion 62 facing the ultraviolet light sources E are formed from a low-reflectivity material such as black sponge, with an ultraviolet reflectivity of approximately 0.1% to 10%. In the first embodiment, forming the wall surfaces 601 and 602 using sponge inhibits the intrusion of ink mist into the interior of the cover plate 502 and reduces the possibility of mist contact with the ultraviolet light sources E. More specifically, in the first embodiment, silicone sponge is used for the wall surfaces 601 and 602. This improves the heat resistance of the wall surfaces 601 and 602 and allows them to be flame-retardant, making it a preferred configuration for environments where ultraviolet light is irradiated from the ultraviolet light sources E. In the first embodiment, it is assumed that the wall surface 601 and the wall surface 602 extend in the Z1 direction when the ultraviolet irradiation unit 5 is cross-sectionally viewed in the X-axis direction.

[0092] like Figure 5 As shown, the heat sink 52 is provided on the surface 51z2. In the first embodiment, it is assumed that the heat sink 52 is formed of aluminum.

[0093] Furthermore, in the first embodiment, the ultraviolet irradiation unit 5 is positioned so that the distance from the recording paper PP in the Z-axis direction is between 1 mm and 15 mm. Therefore, according to the first embodiment, since the distance between the ultraviolet irradiation unit 5 and the recording paper PP is maintained at a distance of 1 mm or greater, the risk of contact between the ultraviolet irradiation unit 5 and the recording paper PP can be reduced. Furthermore, according to the first embodiment, since the distance between the ultraviolet irradiation unit 5 and the recording paper PP is set at a distance of 15 mm or less, the intensity of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5 to the recording paper PP can be maintained.

[0094] Furthermore, in the first embodiment, the plurality of ultraviolet light sources E provided in the ultraviolet irradiation unit 5 are arranged such that the irradiation range of the ultraviolet light sources E on the recording paper PP by the ultraviolet light emitted from one ultraviolet light source E overlaps with the irradiation range of the ultraviolet light emitted from the other ultraviolet light source E. Similarly, in the first embodiment, the plurality of ultraviolet light sources E provided in the ultraviolet irradiation unit 5 are arranged such that the irradiation range of the ultraviolet light sources E on the recording paper PP by the ultraviolet light emitted from one ultraviolet light source E overlaps with the irradiation range of the ultraviolet light emitted from the other ultraviolet light source E.

[0095] Figure 6 This is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5 including the ultraviolet light source E and the substrate 51 when the ultraviolet irradiation unit 5 is cut along a plane having the X-axis direction as a normal direction so as to include the ultraviolet light source E.

[0096] like Figure 6 As shown, the ultraviolet light source E includes a light emitting unit 81, a lens unit 82, a sealing unit 83, and two connecting wiring units 84. In the first embodiment, a light emitting diode (UV-LED) that emits ultraviolet light is used as the ultraviolet light source E.

[0097] The light-emitting section 81 is a light-emitting functional layer that emits ultraviolet light. One of the two connecting wiring sections 84 functions as an anode, supplying holes to the light-emitting section 81. The other of the two connecting wiring sections 84 functions as a cathode, supplying electrons to the light-emitting section 81. The holes supplied from one connecting wiring section 84 and the electrons supplied from the other connecting wiring section 84 combine through the light-emitting section 81, causing the light-emitting section 81 to emit light and emit ultraviolet light.

[0098] The lens portion 82 seals the light emitting portion 81 in the Z1 direction. In the first embodiment, the lens portion 82 is assumed to be formed of a transparent resin that transmits ultraviolet light. However, the lens portion 82 may also be formed of silicone. In addition, the lens portion 82 is preferably waterproofed.

[0099] The sealing portion 83 seals the light emitting portion 81 in the Y-axis direction and the X-axis direction. In the first embodiment, the sealing portion 83 is formed of ceramic. However, the sealing portion 83 may also be formed of resin.

[0100] like Figure 6 As shown, the substrate 51 includes a base material 511 , an insulating layer 512 , a resist layer 513 , and a plurality of wirings 514 .

[0101] The plurality of wirings 514 are formed of a conductive material such as copper, and include one wiring 514 electrically connected to one connecting wiring portion 84 and another strip wiring 514 electrically connected to the other connecting wiring portion 84. Furthermore, in the first embodiment, it is assumed that a gold plating 54 is disposed between the ultraviolet light source E and the substrate 51. Furthermore, in the first embodiment, it is assumed that one connecting wiring portion 84 is electrically connected to one wiring 514 via the gold plating 54, and the other connecting wiring portion 84 is electrically connected to the other wiring 514 via the gold plating 54.

[0102] The resist layer 513 electrically insulates one wiring 514 from another wiring 514 .

[0103] The insulating layer 512 electrically insulates the wiring 514 from the base material 511 .

[0104] The base material 511 is formed of aluminum. In the first embodiment, it is assumed that the heat sink 52 is connected to the base material 511 via the grease 53. However, the heat sink 52 may be connected to the base material 511 via a heat sink.

[0105] Heat generated by the light emitting unit 81 is dissipated via, for example, the connection wiring unit 84, the gold plating 54, the wiring 514, the insulating layer 512, the substrate 511, the grease 53, and the heat sink 52. In other words, at least a portion of the heat generated by the ultraviolet light source E is dissipated via the substrate 511.

[0106] Furthermore, in the first embodiment, when the ultraviolet irradiation unit 5 is viewed from above in the Z1 direction, the area of ​​the base material 511 is larger than the area of ​​the ultraviolet light source module 6 in the substrate 51 in which the ultraviolet light source E is provided. Therefore, in the first embodiment, the heat generated by the ultraviolet light source E can be efficiently dissipated from the base material 511.

[0107] A.3. Control of UV light source E

[0108] Below, refer to Figure 7and Figure 8 Next, the control of the ultraviolet light source E based on the temperature detected by the temperature detection integrated circuit 7 will be described.

[0109] Figure 7 2 is a functional block diagram showing an example of the configuration of the temperature detection integrated circuit 7 .

[0110] like Figure 7 As shown, the temperature detection integrated circuit 7 includes a semiconductor temperature sensor 71 and a signal conversion circuit 72 .

[0111] The semiconductor temperature sensor 71 detects temperature and outputs an analog sensor output signal VT indicating the detection result. For example, the semiconductor temperature sensor 71 includes a constant current source and a diode, and outputs the potential difference across the diode that changes with temperature as the sensor output signal VT.

[0112] The signal conversion circuit 72 converts the analog sensor output signal VT into a digital temperature detection signal DT. For example, the signal conversion circuit 72 includes an amplifier circuit 721 that generates an amplified signal AT by amplifying the sensor output signal VT, and an A / D converter circuit 722 that converts the amplified signal AT into a digital form to generate the temperature detection signal DT.

[0113] Furthermore, in the temperature detection integrated circuit 7 , the semiconductor temperature sensor 71 and the signal conversion circuit 72 are packaged as a single integrated circuit.

[0114] Figure 8 : is an explanatory diagram showing an example of temperature change of the radiation flux characteristics of the ultraviolet light source E. Specifically, Figure 8 In FIG. 5 , the horizontal axis shows the temperature TE of the ultraviolet light source E, and the vertical axis shows the radiation flux RE of ultraviolet rays emitted from the ultraviolet light source E. Here, the radiation flux RE refers to the energy of ultraviolet rays emitted from the ultraviolet light source E per unit time.

[0115] like Figure 8 As shown, in the first embodiment, the ultraviolet light source E emits ultraviolet rays with a radiant flux RE0 at a reference temperature TE0, emits ultraviolet rays with a radiant flux RE1 greater than the radiant flux RE0 at a temperature TE1 lower than the reference temperature TE0, and emits ultraviolet rays with a radiant flux RE2 less than the radiant flux RE0 at a temperature TE2 higher than the reference temperature TE0. That is, in the first embodiment, the temperature TE of the ultraviolet light source E and the radiant flux RE of the ultraviolet rays emitted from the ultraviolet light source E have a negative correlation.

[0116] In the first embodiment, the temperature TE1 is an example of the “first temperature”, and the temperature TE2 is an example of the “second temperature”.

[0117] Thus, the radiation flux RE of ultraviolet rays emitted from the ultraviolet light source E depends on the temperature of the ultraviolet light source E. In other words, the intensity of the ultraviolet rays emitted from the ultraviolet light source E depends on the temperature inside the ultraviolet irradiation unit 5 in which the ultraviolet light source E is located. Therefore, for example, if the temperature inside the ultraviolet light source E is higher than the appropriate temperature, the intensity of the ultraviolet rays emitted from the ultraviolet light source E will be lower than the appropriate intensity. Therefore, for example, if the temperature inside the ultraviolet light source E is higher than the appropriate temperature, the ultraviolet rays emitted from the ultraviolet irradiation unit 5 may not be irradiated onto the recording paper PP with ultraviolet rays of the appropriate intensity, and the image quality of the image formed on the recording paper PP may be degraded.

[0118] In contrast, according to the first embodiment, the control unit 2 generates the light source control signal SL based on the temperature detection signal DT output by the signal conversion circuit 72. Therefore, according to the first embodiment, the ultraviolet irradiation unit 5 can irradiate the recording paper PP with ultraviolet rays of an intensity corresponding to the temperature within the ultraviolet irradiation unit 5, thereby suppressing degradation in the image quality of the image formed on the recording paper PP.

[0119] A.4. Irradiation intensity of ultraviolet irradiation unit 5

[0120] Below, refer to Figure 9 and Figure 10 Next, a simulation related to the intensity (illuminance) of ultraviolet rays irradiated from the ultraviolet irradiation unit 5 onto the recording paper PP (hereinafter referred to as “illuminance simulation”) will be described.

[0121] Figure 9 This is an explanatory diagram for explaining the premise of illumination simulation related to ultraviolet irradiation from the ultraviolet irradiation unit 5 .

[0122] like Figure 9 As shown, below, the position of the central axis AX of the center portion of the ultraviolet light source module 6 in the Y-axis direction is set to "Y = 0", the position of the end of the cover plate 502 in the Y-axis direction is set to "Y = L", and the position of the end of the cover plate 502 in the Y-axis direction is set to "Y = -L". In other words, below, it is assumed that the width of the cover plate 502 in the Y-axis direction is "2L". Here, the value L is a real number that satisfies "L > 0". Furthermore, in the illumination simulation, "L = 12.5 mm", that is, "2L = 25 mm" is assumed.

[0123] Hereinafter, the length in the Z-axis direction from the surface 51z1 of the substrate 51 where the ultraviolet light source E is provided to the end of the cover plate 502 in the Z1 direction is referred to as the unit length HW. Furthermore, in the illumination simulation, the unit length HW is assumed to be 8.1 mm.

[0124] Hereinafter, the length in the Z-axis direction from the Z1 end of the cover plate 502 to the Z2 end of the platen 95 is referred to as the platen gap HP. In the illumination simulation, the platen gap HP is assumed to be 1.2 mm.

[0125] In the illumination simulation, the value NY is assumed to be “4” and the value NX is assumed to be “16.” That is, in the illumination simulation, a total of “64” ultraviolet light sources E are arranged in 16 rows and 4 columns in the ultraviolet light source module 6 .

[0126] In the illumination simulation, it is assumed that the total amount of ultraviolet light emitted from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 in one second is “83 W”.

[0127] In the illumination simulation, it is assumed that the distance dLX is “4.4 mm” and the distance dLY is “4.6 mm”.

[0128] In the illumination simulation, it is assumed that the reflectivity of the wall surfaces 601 and 602 is “5%”, the reflectivity of the surface 51z1 is “10%”, and the refractive index of the cover plate 502 is “1.5”.

[0129] Figure 10 : is a diagram showing the results of the illumination simulation according to the first embodiment. Specifically, Figure 10 It is shown in Figure 9 Under the illumination simulation conditions shown in FIG. 1 , the illumination intensity of ultraviolet rays irradiating the recording paper PP placed on the platen 95 is shown in FIG. 2 , when the recording paper PP is cut with a plane having the X-axis direction as the normal direction. Figure 9 The illumination simulation shown is referred to as a first illumination simulation.

[0130] like Figure 10 As shown, in the first illumination simulation, the maximum illumination in the recording paper PP is "5.2 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.18L" to "1.18L". In addition, in the first illuminance simulation, the total illuminance of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5 within 1 second is "62W".

[0131] A.5. Existing Examples

[0132] Below, refer to Figure 11 and Figure 12 , the ultraviolet irradiation unit 5 according to the first embodiment and the ultraviolet irradiation unit according to the conventional example will be described.

[0133] Figure 11The diagram shows an overview of the ultraviolet irradiation unit 5 according to the first embodiment, an overview of the ultraviolet irradiation unit according to Conventional Example 1, and an overview of the ultraviolet irradiation unit according to Conventional Example 2. The ultraviolet irradiation unit according to Conventional Example 1 is manufactured and sold by another company (Company A), and the ultraviolet irradiation unit according to Conventional Example 2 is manufactured and sold by another company (Company B).

[0134] like Figure 11 As shown, the ultraviolet irradiation unit 5 according to the first embodiment includes one unit with a power consumption of 160 W, and the total power consumption is 160 W. In contrast, the ultraviolet irradiation unit according to the conventional example 1 includes two units with a power consumption of 30 W, and the total power consumption is 60 W. Furthermore, the ultraviolet irradiation unit according to the conventional example 2 includes one unit with a power consumption of 250 W, and the total power consumption is 250 W.

[0135] As described above, the ultraviolet irradiation unit 5 according to the first embodiment consumes a large amount of power, similarly to the ultraviolet irradiation unit according to the conventional example, and it is important to efficiently dissipate the heat generated by the ultraviolet irradiation unit 5 .

[0136] like Figure 11 As shown, in the ultraviolet irradiation unit 5 according to the first embodiment, the base material 511 of the substrate 51 included in the ultraviolet irradiation unit 5 is formed of aluminum. That is, the substrate 51 provided in the ultraviolet irradiation unit 5 is a so-called aluminum substrate. In contrast, the base material of the substrate included in the ultraviolet irradiation unit according to Conventional Example 1 is formed of copper, and similarly, the base material of the substrate included in the ultraviolet irradiation unit according to Conventional Example 2 is also formed of copper. That is, the substrates provided in the ultraviolet irradiation units according to Conventional Examples 1 and 2 are so-called copper substrates.

[0137] Figure 12 is a graph showing the thermal conductivity and specific gravity of various metals.

[0138] like Figure 12 As shown in the figure, the thermal conductivity of copper is 398W / mk. Therefore, compared with the thermal conductivity of aluminum (236W / mk), the thermal conductivity of iron (67W / mk), and the thermal conductivity of stainless steel (16W / mk), the thermal conductivity of copper is higher. That is, as in the conventional example, by adopting a copper substrate in the substrate of the ultraviolet irradiation unit, the heat generated in the ultraviolet irradiation unit can be efficiently dissipated. In addition, as raw materials with higher thermal conductivity than copper, there are silver with a thermal conductivity of 398W / mk and diamond with a thermal conductivity of 1000W / mk, but due to the high cost of these raw materials, it is not practical to use them as substrates for ultraviolet irradiation units. Therefore, it has been customary to adopt a copper substrate as the substrate of the ultraviolet irradiation unit.

[0139] On the other hand, Figure 12 As shown, the specific gravity of aluminum is 2.7g / cm 3 Therefore, the specific gravity of copper is 8.9g / cm 3 , the specific gravity of iron is 7.8g / cm 3 And the specific gravity of stainless steel is 7.9g / cm 3 In comparison, the specific gravity of aluminum is smaller. Therefore, the ultraviolet irradiation unit 5 involved in the first embodiment can achieve lightweighting of the substrate 51, and thus lightweighting of the ultraviolet irradiation unit 5, compared to the ultraviolet irradiation unit involved in the prior art example 1 and the ultraviolet irradiation unit involved in the prior art example 2. As a result, the ultraviolet irradiation unit 5 involved in the first embodiment can reduce the load involved in the carriage conveying motor 91 that drives the carriage 110 when the ultraviolet irradiation unit 5 is mounted on the carriage 110 and the ultraviolet irradiation unit 5 is moved. That is, the ultraviolet irradiation unit 5 involved in the first embodiment can extend the life of the carriage conveying motor 91 and reduce the amount of electricity involved in driving the carriage conveying motor 91, compared to the solution in which the ultraviolet irradiation unit involved in the prior art example 1 or the ultraviolet irradiation unit involved in the prior art example 2 is mounted on the carriage 110.

[0140] Furthermore, as mentioned above, the thermal conductivity of aluminum is lower than that of copper but higher than that of iron and stainless steel. Therefore, the ultraviolet irradiation unit 5 according to the first embodiment can achieve both a reduction in the load on the carriage transport motor 91 that drives the carriage 110 and efficient heat dissipation of the ultraviolet irradiation unit 5.

[0141] In addition, a radiator is generally installed in an ultraviolet irradiation unit that generates a lot of heat to improve the heat dissipation of the ultraviolet irradiation unit. In addition, the radiator is generally made of aluminum. Therefore, when a radiator made of aluminum is installed in an ultraviolet irradiation unit that uses a copper substrate, as in the ultraviolet irradiation unit involved in Existing Example 1 and the ultraviolet irradiation unit involved in Existing Example 2, the possibility of corrosion occurring at the boundary between the copper substrate and the aluminum becomes higher. Therefore, when a radiator made of aluminum is installed in an ultraviolet irradiation unit that uses a copper substrate, as in the existing example, in order to prevent corrosion at the boundary between the copper substrate and the aluminum radiator, a heat sink is generally interposed between the copper substrate and the radiator. Therefore, in an ultraviolet irradiation unit that uses a copper substrate, as in the existing example, the enlargement of the ultraviolet irradiation unit, the high cost of the ultraviolet irradiation unit, and the increase in the number of components of the ultraviolet irradiation unit sometimes become problems.

[0142] In contrast, the ultraviolet irradiation unit 5 according to the first embodiment adopts an aluminum substrate in which the base material 511 is formed of aluminum as the base material 51. Therefore, in the ultraviolet irradiation unit 5 according to the first embodiment, corrosion at the boundary between the base material 511 formed of aluminum and the heat sink 52 formed of aluminum does not become a problem. Therefore, in the ultraviolet irradiation unit 5 according to the first embodiment, it is not necessary to interpose a heat sink between the base material 51 and the heat sink 52, and it is sufficient to interpose grease 53 between the base material 51 and the heat sink 52. Therefore, the ultraviolet irradiation unit 5 according to the first embodiment can achieve miniaturization of the ultraviolet irradiation unit 5, cost reduction of the ultraviolet irradiation unit 5, and reduction in the number of components of the ultraviolet irradiation unit 5, as compared with the ultraviolet irradiation unit using a copper base material as in the conventional example.

[0143] Furthermore, aluminum, as a raw metal for base metals, has a production volume second only to iron, and exceeds iron in terms of its reserves and current demand. Furthermore, aluminum is a metal with excellent recyclability compared to copper. On the other hand, copper resources are limited, and it is estimated that by 2050, the amount of copper used will exceed the current reserves. In contrast, in the first embodiment, an aluminum substrate having a base material 511 formed of aluminum is used in the ultraviolet irradiation unit 5. Therefore, according to the first embodiment, compared with a solution in which a copper substrate is used for the ultraviolet irradiation unit 5, the environmental load can be reduced, and it can be said that this is a solution that takes into account the future "copper shortage."

[0144] like Figure 11 As shown, the temperature sensor included in the ultraviolet irradiation unit of Conventional Example 1 is a thermistor. Similarly, the temperature sensor included in the ultraviolet irradiation unit of Conventional Example 2 is also a thermistor. Thus, in ultraviolet irradiation units, thermistors have generally been used as temperature sensors for detecting the temperature of the ultraviolet irradiation unit. However, thermistors output the detected temperature as an analog signal. Therefore, when the ultraviolet irradiation unit is mounted on a carriage together with the liquid ejection unit, noise caused by various signals driving the liquid ejection unit overlaps with the analog signal output from the thermistor, making it difficult to accurately determine the temperature of the ultraviolet irradiation unit.

[0145] In contrast, the ultraviolet irradiation unit 5 according to the first embodiment includes an integrated circuit (i.e., a temperature detection integrated circuit 7) as a temperature sensor for detecting the temperature of the ultraviolet irradiation unit 5. Furthermore, the temperature detection integrated circuit 7 outputs a temperature detection signal DT, which is a digital signal indicating the temperature detection result of the ultraviolet irradiation unit 5. Therefore, according to the first embodiment, even when the ultraviolet irradiation unit 5 is mounted on the carriage 110 together with the liquid ejection unit 3, the temperature detection signal DT output by the temperature detection integrated circuit 7 can be prevented from being affected by various signals, such as the drive signal Com, that drives the liquid ejection unit 3. In other words, according to the first embodiment, the temperature of the ultraviolet irradiation unit 5 can be more accurately determined than in conventional solutions that use a thermistor as a temperature sensor.

[0146] B. Second embodiment

[0147] Below, refer to Figures 13 to 22 In the following, elements having the same functions or effects as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and detailed descriptions thereof are omitted as appropriate.

[0148] Figure 13 This is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5B included in the inkjet printer according to the second embodiment, when the ultraviolet irradiation unit 5B is cut along a plane whose normal direction is the X-axis direction. The inkjet printer according to the second embodiment has the same configuration as the inkjet printer 1 according to the first embodiment, except that the ultraviolet irradiation unit 5B is included instead of the ultraviolet irradiation unit 5.

[0149] like Figure 13 As shown, the ultraviolet irradiation unit 5B has the same configuration as the ultraviolet irradiation unit 5 according to the first embodiment, except that it includes a wall portion 61B instead of the wall portion 61 and a wall portion 62B instead of the wall portion 62 .

[0150] The wall portion 61B includes a wall surface 601B facing the ultraviolet light source E.

[0151] When the ultraviolet irradiation unit 5B is viewed in a cross-section along the X-axis, the wall surface 601B extends in a direction between the Z1 and Y1 directions, forming an angle θ1 with the Z1 direction. Here, the angle θ1 is between 0 degrees and 30 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 5 degrees and 10 degrees. Furthermore, the wall surface 601B is a reflective surface with a reflectivity of 70% or more, preferably 85% or more, and more preferably 90% or more.

[0152] The wall portion 62B includes a wall surface 602B facing the ultraviolet light source E.

[0153] When the ultraviolet irradiation unit 5B is viewed in a cross-section along the X-axis, the wall surface 602B extends in a direction between the Z1 and Y2 directions, forming an angle θ2 with the Z1 direction. Here, the angle θ2 is between 0 degrees and 30 degrees, preferably between 5 degrees and 15 degrees, and more preferably between 5 degrees and 10 degrees. Furthermore, the wall surface 602B is a reflective surface with a reflectivity of 70% or more, preferably 85% or more, and more preferably 90% or more.

[0154] Figure 14 This is an explanatory diagram for explaining the premise of illumination simulation related to ultraviolet irradiation from the ultraviolet irradiation unit 5B.

[0155] like Figure 14 As shown, in the illumination simulation of the second embodiment, similar to the first embodiment, the Y-axis position of the end of the cover plate 502 in the Y1 direction is "Y = L", the Y-axis position of the end of the cover plate 502 in the Y2 direction is "Y = -L", and the Y-axis width of the cover plate 502 is "2L = 25 mm". Also, similar to the first embodiment, the illumination simulation of the second embodiment assumes a unit length HW of "8.1 mm" and a platen gap HP of "1.2 mm". Also, similar to the first embodiment, the illumination simulation of the second embodiment assumes a case where the number of NY columns is "4", the number of NX rows is "16", the interval dLX is "4.4 mm", and the interval dLY is "4.6 mm". Also, similar to the first embodiment, the illumination simulation of the second embodiment assumes a case where the total amount of ultraviolet light emitted per second by the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 is "83 W". In the illumination simulation of the second embodiment, similarly to the first embodiment, it is assumed that the reflectivity of the surface 51z1 is “10%” and the refractive index of the cover plate 502 is “1.5”.

[0156] In the illumination simulation of the second embodiment, it is assumed that the reflectance of the wall surface 601B and the wall surface 602B is “90%”.

[0157] Furthermore, as described above, when the ultraviolet irradiation unit 5B is cross-sectioned in the X-axis direction, the wall surface 601B extends in a direction between the Z1 direction and the Y1 direction and in a direction that forms an angle θ1 with the Z1 direction. Figure 14 As shown, when the distance in the Z1 direction from the substrate 51 is distance dZ1 (an example of a "first distance"), the distance dY1 in the Y1 direction between the wall surface 601B and the liquid ejection unit 3 is greater than the distance dY2 in the Y1 direction between the wall surface 601B and the liquid ejection unit 3 when the distance in the Z1 direction from the substrate 51 is distance dZ2 (an example of a "second distance") longer than distance dZ1. However, when the angle θ1 satisfies "θ1>0," the distance dY1 is greater than the distance dY2.

[0158] Figure 15 It is shown in Figure 14 1 and 2 show results of an illumination simulation (hereinafter referred to as a “second illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B onto the recording paper PP in the cross-section of interest when the angle θ1 is set to “0 degrees” and the angle θ2 is set to “0 degrees”.

[0159] like Figure 15 As shown, in the second illumination simulation, the maximum illumination in the recording paper PP is "6.3 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.34L" to "1.34L". In addition, in the second illuminance simulation, the total illuminance of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "75W".

[0160] Figure 16 It is shown in Figure 14 1 and 2 show results of an illumination simulation (hereinafter referred to as a “third illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B onto the recording paper PP in the cross-section of interest when the angle θ1 is set to “5 degrees” and the angle θ2 is set to “5 degrees”.

[0161] like Figure 16 As shown, in the third illumination simulation, the maximum illumination in the recording paper PP is "6.0 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.08L" to "1.08L". In addition, in the third illuminance simulation, the total illuminance of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "76W".

[0162] Figure 17 It is shown in Figure 14 1 and 2 show the results of an illumination simulation (hereinafter referred to as a “fourth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cross-section of interest when the angle θ1 is set to “10 degrees” and the angle θ2 is set to “10 degrees”.

[0163] like Figure 17 As shown, in the fourth illumination simulation, the maximum illumination in the recording paper PP is "5.7 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.34L" to "1.34L". In addition, in the fourth illumination simulation, the total illumination value of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "77W".

[0164] Figure 18 It is shown in Figure 14 1 is a diagram showing the results of an illumination simulation (hereinafter referred to as a “fifth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cross-section of interest when the angle θ1 is set to “15 degrees” and the angle θ2 is set to “15 degrees”.

[0165] like Figure 18 As shown, in the fifth illumination simulation, the maximum illumination in the recording paper PP is "5.4 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.36L" to "1.36L". In addition, in the fifth illumination simulation, the total illumination value of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "77W".

[0166] Figure 19 It is shown in Figure 14 1 is a diagram showing the results of an illumination simulation (hereinafter referred to as a “sixth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cross-section of interest when the angle θ1 is set to “20 degrees” and the angle θ2 is set to “20 degrees”.

[0167] like Figure 19 As shown, in the sixth illumination simulation, the maximum illumination in the recording paper PP is "5.2 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.38L" to "1.38L". In addition, in the sixth illuminance simulation, the total illuminance of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "77W".

[0168] Figure 20 It is shown in Figure 141 is a diagram showing the results of an illumination simulation (hereinafter referred to as a “seventh illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cross-section of interest when the angle θ1 is set to “30 degrees” and the angle θ2 is set to “30 degrees”.

[0169] like Figure 20 As shown, in the seventh illumination simulation, the maximum illumination in the recording paper PP is "5.2 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.24L" to "1.24L". In addition, in the seventh illumination simulation, the total illumination value of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "76W".

[0170] Figure 21 It is shown in Figure 14 1 and 2 show the results of an illumination simulation (hereinafter referred to as an “eighth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cross-section of interest when the angle θ1 is set to “45 degrees” and the angle θ2 is set to “45 degrees”.

[0171] like Figure 21 As shown, in the eighth illumination simulation, the maximum illumination in the recording paper PP is "5.1 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is from "-1.45L" to "1.45L". In addition, in the eighth illumination simulation, the total illumination value of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5B within 1 second is "76W".

[0172] Figure 22 It is shown from Figures 15 to 21 The results of the second illumination simulation to the eighth illumination simulation are shown in FIG. Figure 22 In FIG. 1 , the solid line FW shows the maximum illuminance WM of each illuminance simulation, and the dotted line FK shows the irradiation efficiency α of each illuminance simulation. Here, the irradiation efficiency α is the value obtained by dividing the total value of the illuminance irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in 1 second in each illuminance simulation by the total amount of ultraviolet rays emitted from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 in 1 second. Figure 22 In the equation, it is assumed that “θ1=θ2=θ”.

[0173] like Figure 22As shown by the solid line FW, as the angle θ decreases, the maximum illuminance WM increases. Therefore, to more reliably cure the ink through ultraviolet irradiation, it is preferable to increase the maximum illuminance WM by decreasing the angle θ. Therefore, from the perspective of ink curing reliability, for example, the angle θ is preferably within the range of "0 degrees to 15 degrees," and more preferably within the range of "0 degrees to 10 degrees."

[0174] On the other hand, in order to improve the irradiation efficiency α of ultraviolet rays from the ultraviolet irradiation unit 5B, it is preferable that the angle θ be in the range of “5 degrees or more and 45 degrees or less”.

[0175] In contrast, in the second embodiment, the angle θ is set to "between 0 degrees and 30 degrees," preferably "between 5 degrees and 15 degrees," and more preferably "between 5 degrees and 10 degrees." Therefore, the second embodiment achieves both improved ink curing reliability by increasing the maximum illuminance WM and reduced power required to drive the ultraviolet irradiation unit 5B by increasing the irradiation efficiency α.

[0176] C. Third embodiment

[0177] Below, refer to Figures 23 to 26 , an inkjet printer according to the third embodiment will be described. Furthermore, for elements in the following exemplary embodiments that have the same effects or functions as those in the first or second embodiment, the reference numerals used in the description of the first or second embodiment will be used, and detailed descriptions thereof will be omitted as appropriate.

[0178] Figure 23 This is a cross-sectional view showing an example of the configuration of the ultraviolet irradiation unit 5C included in the inkjet printer according to the third embodiment, when the ultraviolet irradiation unit 5C is cut along a plane whose normal direction is the X-axis direction. The inkjet printer according to the third embodiment has the same configuration as the inkjet printer 1 according to the first embodiment, except that the ultraviolet irradiation unit 5C is included instead of the ultraviolet irradiation unit 5.

[0179] like Figure 23As shown, the ultraviolet irradiation unit 5C has the same configuration as the ultraviolet irradiation unit 5 according to the first embodiment, except that it includes a wall portion 61B in place of the wall portion 61. Specifically, the ultraviolet irradiation unit 5C includes a wall portion 61B having a wall surface 601B with a reflectivity of 70% or higher between the ultraviolet light source E and the liquid ejection unit 3, and a wall portion 62 having a wall surface 602 with a reflectivity of approximately 0.1% to 10% on the side opposite the liquid ejection unit 3 when viewed from the ultraviolet light source E. In other words, in the ultraviolet irradiation unit 5C, the wall surface 602 located on the side opposite the liquid ejection unit 3 when viewed from the ultraviolet light source E has a higher light absorptivity than the wall surface 601B located between the ultraviolet light source E and the liquid ejection unit 3. In addition, in the third embodiment, as in the first or second embodiment, it is assumed that when the ultraviolet irradiation unit 5C is cross-sectioned in the X-axis direction, the wall 601B extends in a direction between the Z1 direction and the Y1 direction, at an angle θ1 with the Z1 direction, and the wall 602 extends in the Z1 direction.

[0180] Figure 24 This is an explanatory diagram for explaining the premise of illumination simulation related to ultraviolet irradiation from the ultraviolet irradiation unit 5C.

[0181] like Figure 24 As shown, in the illumination simulation of the third embodiment, similar to the first embodiment, the Y-axis position of the end of the cover plate 502 in the Y1 direction is "Y = L", the Y-axis position of the end of the cover plate 502 in the Y2 direction is "Y = -L", and the Y-axis width of the cover plate 502 is "2L = 25 mm". Also, similar to the first embodiment, the illumination simulation of the third embodiment assumes a unit length HW of "8.1 mm" and a platen gap HP of "1.2 mm". Also, similar to the first embodiment, the illumination simulation of the third embodiment assumes a NY column of "4", a NX row of "16", a spacing dLX of "4.4 mm", and a spacing dLY of "4.6 mm". Also, similar to the first embodiment, the illumination simulation of the third embodiment assumes a total amount of ultraviolet light emitted per second by the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 of "83 W". In addition, in the illumination simulation of the third embodiment, as in the first and second embodiments, it is assumed that the reflectivity of surface 51z1 is "10%", the reflectivity of wall 601B is "90%", the reflectivity of wall 602 is "5%", and the refractive index of cover 502 is "1.5".

[0182] Figure 25 It is shown in Figure 241 is a diagram showing the results of an illumination simulation (hereinafter referred to as a “ninth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5C onto the recording paper PP in the cross-section of interest when the angle θ1 is set to “0 degrees”.

[0183] like Figure 25 As shown, in the ninth illumination simulation, the maximum illumination in the recording paper PP is "5.9 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is in the range of "-1.34L" to "1.29L". In addition, in the ninth illumination simulation, the total value of the illumination of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5C within 1 second is "68W". In addition, in the ninth illumination simulation, the illumination of the area where "Y>0" is obtained is lower than the illumination of the area where "Y<0" is obtained. In other words, in the ninth illumination simulation, the illumination of the area closer to the liquid ejection unit 3 than the center axis AX is lower than the illumination of the area farther away from the liquid ejection unit 3 than the center axis AX.

[0184] Figure 26 It is shown in Figure 24 1 is a diagram showing the results of an illumination simulation (hereinafter referred to as a “tenth illumination simulation”) concerning the illumination intensity of ultraviolet rays irradiated from the ultraviolet irradiation unit 5C onto the recording paper PP in the cross-section of interest when the angle θ1 is set to “30 degrees”.

[0185] like Figure 26 As shown, in the tenth illumination simulation, the maximum illumination in the recording paper PP is "5.4 W / cm 2 ", focusing on the range of the ultraviolet rays reaching the cut surface, which is in the range of "-1.34L" to "1.33L". In addition, in the tenth illumination simulation, the total value of the illumination of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5C within 1 second is "70W". In addition, in the tenth illumination simulation, the illumination of the area where "Y>0" is obtained is lower than the illumination of the area where "Y<0" is obtained. In other words, in the tenth illumination simulation, the illumination of the area closer to the liquid ejection unit 3 than the center axis AX is lower than the illumination of the area farther away from the liquid ejection unit 3 than the center axis AX.

[0186] As described above, according to the third embodiment, since the reflectivity of wall surface 602 is lower than that of wall surface 601B, the illuminance of ultraviolet rays emitted from ultraviolet irradiation unit 5C in the Y1 direction can be lower than the illuminance of ultraviolet rays emitted from ultraviolet irradiation unit 5C in the Y2 direction. Therefore, according to the third embodiment, compared with the second embodiment, the amount of ultraviolet rays emitted from ultraviolet irradiation unit 5C that are reflected by recording paper PP and reach liquid ejection unit 3 can be reduced. In other words, according to the third embodiment, the possibility of abnormal discharge from ejection portion D caused by ultraviolet rays irradiating liquid ejection unit 3 can be reduced compared with the second embodiment.

[0187] D. Modification

[0188] Each of the above embodiments can be modified in various ways. Specific modified embodiments are illustrated below. Two or more embodiments arbitrarily selected from the following examples can be appropriately combined within the scope of mutual non-contradiction. In addition, for elements in the following illustrated modifications that have the same effects or functions as those in the embodiment, the same reference numerals as those in the above description are used, and their detailed descriptions are appropriately omitted.

[0189] D.1. Modification 1

[0190] In the above-mentioned first to third embodiments, the lens portion 82 of the ultraviolet light source E may be characterized in that a height dEZ of the lens portion 82 in the Z-axis direction is longer than a width dEY of the lens portion 82 in the Y-axis direction, and is longer than a width dEX (not shown) of the lens portion 82 in the X-axis direction.

[0191] Figure 27 This is a cross-sectional view showing an example of the configuration of the ultraviolet light source E according to Modification 1, when the ultraviolet light source E is cut along a plane whose normal direction is the X-axis direction.

[0192] like Figure 27 As shown, the ultraviolet light source E according to Modification 1 includes, similarly to the ultraviolet light source E according to the embodiment, a light emitting section 81, a lens section 82, a sealing section 83, and a connecting wiring section 84. In Modification 1, the lens section 82 includes a cylindrical base section 821 and a hemispherical tip section 822.

[0193] The base portion 821 has a height dEZ1 in the Z-axis direction and a width dEY in the X-axis direction and the Y-axis direction. That is, when viewed from the Z-axis direction, the base portion 821 has a circular shape with a diameter dEY.

[0194] The tip portion 822 is connected to the base portion 821 in the Z1 direction when viewed from the base portion 821, has a height dEZ2 in the Z-axis direction, and has a width dEY in the X-axis and Y-axis directions. In other words, the tip portion 822 has a circular shape with a diameter dEY when viewed from the Z-axis direction.

[0195] In this modification, lens portion 82 has a shape such that height dEZ1, height dEZ2, and width dEY satisfy the equation "dEZ1 + dEZ2 = dEZ > dEY." That is, in this modification, lens portion 82 has a shape such that its length in the Z-axis direction is greater than the diameter of base portion 821.

[0196] Figure 28 This figure shows an example of the directional characteristics of the ultraviolet light source E in this modification and the directional characteristics of the ultraviolet light source in the comparative example. The ultraviolet light source in the comparative example has the same configuration as the ultraviolet light source E in Modification 1, except that the length of the lens portion 82 in the Z-axis direction is shorter than the diameter of the base portion 821.

[0197] like Figure 28 As shown, the ultraviolet light source E according to Modification 1 has higher directivity, as indicated by curve FS1. On the other hand, the ultraviolet light source in the comparative example has lower directivity, as indicated by curve FS2. Therefore, by employing the ultraviolet light source E according to Modification 1 as the ultraviolet light source E used in the ultraviolet irradiation unit 5 (or ultraviolet irradiation unit 5B or ultraviolet irradiation unit 5C), the irradiation efficiency of the ultraviolet rays emitted from the ultraviolet irradiation unit 5 can be improved. Furthermore, the likelihood of ultraviolet rays emitted from the ultraviolet irradiation unit 5 being reflected by the recording paper PP and reaching the liquid ejection unit 3 can be reduced.

[0198] D.2. Modification 2

[0199] While the first to third embodiments and Modification 1 described above illustrate and describe an inkjet printer 1 in which a single ultraviolet irradiation unit 5 is provided in the Y2 direction as viewed from the liquid ejection unit 3, the present invention is not limited to this embodiment. The inkjet printer 1 may alternatively be provided with a total of two ultraviolet irradiation units 5: one ultraviolet irradiation unit 5 in the Y2 direction as viewed from the liquid ejection unit 3, and one ultraviolet irradiation unit 5 in the Y1 direction as viewed from the liquid ejection unit 3. In this case, the inkjet printer 1 moves the carriage 110 in the Y1 direction while ink is ejected from the liquid ejection unit 3 onto the recording paper PP and the ultraviolet irradiation unit 5 in the Y2 direction as viewed from the liquid ejection unit 3 irradiates the recording paper PP with ultraviolet light. The inkjet printer 1 performs a printing process while ink is ejected from the liquid ejection unit 3 onto the recording paper PP and the ultraviolet irradiation unit 5 in the Y1 direction as viewed from the liquid ejection unit 3 irradiates the recording paper PP with ultraviolet light.

[0200] D.3. Modification 3

[0201] In the first to third embodiments and Modifications 1 and 2 described above, it is assumed that the inkjet printer 1 includes four liquid ejection units 3. However, the present invention is not limited to this configuration. The inkjet printer 1 may include one or more liquid ejection units 3, but may include three or less liquid ejection units 3, or may include five or more liquid ejection units 3.

[0202] E. Notes

[0203] The following describes the aspects that can be understood from the above description. In order to facilitate understanding of each aspect, the following figures are given with reference numerals in parentheses for convenience, but the present invention is not limited to the aspects shown in the figures.

[0204] E.1. Note 1

[0205] Hereinafter, the inkjet printer 1 according to Supplementary Note 1 will be described.

[0206] Note 1-1

[0207] The inkjet printer 1 involved in Note 1-1 is characterized in that it includes: a liquid ejection unit 3, which ejects ink cured by ultraviolet irradiation to the recording paper PP; an ultraviolet irradiation unit 5, which irradiates ultraviolet rays to the ink ejected onto the recording paper PP; a slide 110, which carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5 and moves on the recording paper PP; and a slide conveying motor 91, which is used to move the slide 110, and the ultraviolet irradiation unit 5 includes: a substrate 51; and an ultraviolet light source E, which is arranged on the substrate 51 and emits ultraviolet rays, and the substrate 51 has an aluminum substrate 511.

[0208] According to Supplementary Note 1-1, since the ultraviolet irradiation unit 5 employs a substrate 51 having an aluminum base material 511, the ultraviolet irradiation unit 5 can be made lighter than a solution in which the ultraviolet irradiation unit employs a substrate having a copper base material. Therefore, according to Supplementary Note 1-1, the load applied to the carriage transport motor 91 that moves the carriage 110 carrying the ultraviolet irradiation unit 5 can be reduced, thereby extending the life of the carriage transport motor 91 and reducing the amount of power required to drive the carriage transport motor 91.

[0209] Notes 1-2

[0210] The inkjet printer 1 according to Supplementary Note 1-2 is characterized in that, in the inkjet printer 1 according to Supplementary Note 1-1, at least a portion of the heat generated in the ultraviolet light source E is dissipated via the substrate 511 .

[0211] Notes 1-3

[0212] The inkjet printer 1 according to Supplementary Note 1-3 is characterized in that, in the inkjet printer 1 according to Supplementary Note 1-1 or Supplementary Note 1-2, the surface area of ​​the substrate 51 is larger than the area of ​​the region where the ultraviolet light source E is provided on the substrate 51 .

[0213] According to Supplementary Notes 1-3, compared with a case where the surface area of ​​the substrate 51 is smaller than the area of ​​the region where the ultraviolet light source E is provided, the heat generated in the ultraviolet light source E can be dissipated efficiently.

[0214] Notes 1-4

[0215] The inkjet printer 1 according to Supplementary Note 1-4 is characterized in that, in the inkjet printer 1 according to Supplementary Notes 1-1 to 1-3, a heat sink 52 made of aluminum is attached to a base material 511 .

[0216] According to Supplementary Notes 1-4, since the aluminum heat sink 52 is attached to the aluminum substrate 511, the possibility of corrosion occurring at the boundary between the substrate 511 and the heat sink 52 can be reduced compared to a solution in which the aluminum heat sink 52 is attached to a copper substrate. Therefore, according to Supplementary Notes 1-4, there is no need to interpose a heat sink between the substrate 511 and the heat sink 52, thereby achieving miniaturization of the ultraviolet irradiation unit 5, reducing the number of components of the ultraviolet irradiation unit 5, and increasing the degree of freedom in the design of the ultraviolet irradiation unit 5.

[0217] Notes 1-5

[0218] The inkjet printer 1 according to Supplementary Note 1-5 is characterized in that, in the inkjet printer 1 according to Supplementary Note 1-1 to Supplementary Note 1-4, the ultraviolet light source E is a light emitting diode (UV-LED) that emits ultraviolet rays.

[0219] According to Supplement 1-5, since a light emitting diode is used as the ultraviolet light source E, compared with the solution using a conventional light source such as a high-pressure mercury lamp or a xenon lamp as the ultraviolet light source E, it generates less heat and is smaller, making it suitable for mounting on the slide 110.

[0220] Notes 1-6

[0221] The inkjet printer 1 according to Supplementary Note 1 - 6 is characterized in that a semiconductor temperature sensor 71 is provided on the substrate 51 in the inkjet printer 1 according to Supplementary Note 1 - 1 to Supplementary Note 1 - 5 .

[0222] According to Supplementary Notes 1-6, the temperature of the ultraviolet irradiation unit 5 can be grasped, and based on the temperature of the ultraviolet irradiation unit 5, it is possible to determine whether the ultraviolet light source E needs to be stopped or adjust the emission intensity of the ultraviolet light source E.

[0223] Notes 1-7

[0224] The inkjet printer 1 involved in Note 1-7 is characterized in that, in the inkjet printer 1 involved in Notes 1-1 to 1-6, a signal conversion circuit 72 for converting the output from the semiconductor temperature sensor 71 into a digital signal is provided on the substrate 51, and the semiconductor temperature sensor 71 and the signal conversion circuit 72 are packaged as an integrated circuit 7 for temperature detection as an integrated circuit.

[0225] According to Supplementary Note 1-7, the possibility of noise being superimposed on the output signal from the temperature detection integrated circuit 7 can be reduced compared to a case where the output from the temperature detection integrated circuit 7 is an analog signal.

[0226] Notes 1-8

[0227] The inkjet printer 1 involved in Note 1-8 is characterized in that, in the inkjet printer 1 involved in Notes 1-1 to 1-7, the ultraviolet irradiation unit 5 has a housing 50 including a cover 502 and a frame 501 that allows ultraviolet rays to pass through, and the substrate 51 and the ultraviolet light source E are arranged in the housing 50.

[0228] E.2. Note 2

[0229] Hereinafter, the inkjet printer 1 according to Supplementary Note 2 will be described.

[0230] Appendix 2-1

[0231] The inkjet printer 1 involved in Note 2-1 is characterized in that it comprises: a liquid ejection unit 3, which ejects ink cured by ultraviolet irradiation onto the recording paper PP; an ultraviolet irradiation unit 5, which irradiates ultraviolet rays on the ink ejected onto the recording paper PP; a slide 110, which carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5 and moves on the recording paper PP; and a slide conveying motor 91, which is used to move the slide 110, and the ultraviolet irradiation unit 5 comprises: a substrate 51; an ultraviolet light source E, which is arranged on the substrate 51, and has a radiation flux characteristic that changes according to the temperature and emits ultraviolet rays; and an integrated circuit 7 for temperature detection, which is an integrated circuit that detects the temperature inside the ultraviolet irradiation unit 5 and outputs a digital temperature detection signal DT based on the detected temperature.

[0232] According to Supplementary Note 2-1, since the temperature detection integrated circuit 7 detects the temperature within the ultraviolet irradiation unit 5, it is possible to determine whether the ultraviolet light source E needs to be stopped or to adjust the emission intensity of the ultraviolet light source E based on the detected temperature within the ultraviolet irradiation unit 5. Furthermore, according to Supplementary Note 2-1, since the temperature detection integrated circuit 7 outputs the temperature detection signal DT as a digital signal, the possibility of noise being superimposed on the temperature detection signal DT output from the temperature detection integrated circuit 7 can be reduced compared to a solution in which the output from the temperature detection integrated circuit 7 is an analog signal.

[0233] Note 2-2

[0234] The inkjet printer 1 involved in Note 2-2 is characterized in that, in the inkjet printer 1 involved in Note 2-1, the radiation flux RE1 of ultraviolet rays emitted from the ultraviolet light source E at temperature TE1 is greater than the radiation flux RE2 of ultraviolet rays emitted from the ultraviolet light source E at temperature TE2 which is higher than temperature TE1.

[0235] Notes 2-3

[0236] The inkjet printer 1 involved in Note 2-3 is characterized in that, in the inkjet printer 1 involved in Note 2-1 or Note 2-2, the temperature detection integrated circuit 7 includes: a semiconductor temperature sensor 71, which detects temperature and outputs a sensor output signal VT as an analog signal indicating the result of the detection; and a signal conversion circuit 72, which converts the sensor output signal VT output by the semiconductor temperature sensor 71 into a temperature detection signal DT as a digital signal.

[0237] According to Note 2-3, since the temperature detection integrated circuit 7 outputs the temperature detection signal DT as a digital signal, the possibility of noise being superimposed on the temperature detection signal DT output from the temperature detection integrated circuit 7 can be reduced compared to a solution in which the output from the temperature detection integrated circuit 7 is an analog signal.

[0238] Notes 2-4

[0239] The inkjet printer 1 involved in Note 2-4 is characterized in that, in the inkjet printer 1 involved in Notes 2-1 to 2-3, there is a control unit 2, which controls the emission of ultraviolet rays from the ultraviolet light source E based on the digital signal output from the temperature detection integrated circuit 7, namely the temperature detection signal DT.

[0240] According to Supplementary Note 2-4, since the emission of ultraviolet light from the ultraviolet light source E is controlled based on the temperature within the ultraviolet light irradiation unit 5, the ink on the recording paper PP can be irradiated with ultraviolet light of an appropriate intensity. This improves the print quality of the inkjet printer 1 compared to a solution in which the intensity of the ultraviolet light is not adjusted. Furthermore, according to Supplementary Note 2-4, the emission of ultraviolet light from the ultraviolet light source E at an inappropriate intensity can be suppressed, thereby suppressing the degradation of print quality of the inkjet printer 1 that would otherwise occur due to the inappropriate intensity of ultraviolet light irradiation on the recording paper PP.

[0241] Notes 2-5

[0242] The inkjet printer 1 according to Note 2-5 is characterized in that, in the inkjet printer 1 according to Notes 2-1 to 2-4, the ultraviolet light source E comprises: a light emitting portion 81 for emitting ultraviolet rays; and a lens portion 82 for sealing the light emitting portion 81 and applying a waterproof treatment to the lens portion 82.

[0243] According to Supplementary Note 2-5, it is possible to suppress a decrease in the illuminance of the ultraviolet irradiation unit 5 due to adhesion of ink to the lens portion 82 .

[0244] Notes 2-6

[0245] The inkjet printer 1 according to Supplement 2-6 is characterized in that, in the inkjet printer 1 according to Supplement 2-1 to Supplement 2-5, the ultraviolet light source E includes: a light emitting portion 81 emitting ultraviolet rays; and a lens portion 82 sealing the light emitting portion 81, wherein the lens portion 82 is formed of silicone.

[0246] According to Supplementary Note 2-6, since silicone has water repellency, it is possible to suppress a decrease in the illuminance of the ultraviolet irradiation unit 5 due to adhesion of ink to the lens portion 82 .

[0247] Notes 2-7

[0248] The inkjet printer 1 involved in Note 2-7 is characterized in that, in the inkjet printer 1 involved in Notes 2-1 to 2-5, the ultraviolet light source E includes: a light-emitting portion 81 that emits ultraviolet rays; and a lens portion 82 that seals the light-emitting portion 81, the lens portion 82 is formed of resin, and the ultraviolet irradiation unit 5 includes a cover 502 that is arranged between the ultraviolet light source E and the recording paper PP and allows ultraviolet rays to pass through.

[0249] According to Supplementary Note 2-7, since the cover plate 502 suppresses adhesion of ink to the ultraviolet light source E, it is possible to suppress a decrease in the illuminance of the ultraviolet irradiation unit 5 due to adhesion of ink to the lens portion 82 .

[0250] Notes 2-8

[0251] The inkjet printer 1 according to Supplement 2-8 is characterized in that, in the inkjet printer 1 according to Supplement 2-1 to Supplement 2-7, the ultraviolet irradiation unit 5 includes a substrate 51 , an ultraviolet light source E, and a housing 50 for housing the temperature detection integrated circuit 7 .

[0252] Notes 2-9

[0253] The inkjet printer 1 according to Supplementary Note 2-9 is characterized in that, in the inkjet printer 1 according to Supplementary Notes 2-1 to 2-8, gold plating 54 is applied to the wiring 514 for electrically connecting the ultraviolet light source E to the substrate 51 .

[0254] According to Supplementary Note 2-9, the gold plating 54 can reduce the resistance of the wiring 514, and the intensity of the ultraviolet light emitted from the ultraviolet light source E can be stabilized due to the stable power supply to the ultraviolet light source E.

[0255] Note 2-10

[0256] The inkjet printer 1 involved in Note 2-10 is characterized in that, in the inkjet printer 1 involved in Notes 2-1 to 2-9, the ultraviolet light source E includes: a light-emitting portion 81 that emits ultraviolet rays; a lens portion 82 that seals the light-emitting portion 81; and a packaging portion 83 that protects the light-emitting portion 81, and the packaging portion 83 is formed of ceramic.

[0257] According to Supplementary Note 2-10, since the sealing portion 83 is made of ceramic, degradation of the sealing portion 83 caused by ozone generated by the reaction of ultraviolet rays with oxygen in the air can be suppressed compared to a case where the sealing portion 83 is formed of resin.

[0258] E.3. Note 3

[0259] Hereinafter, the inkjet printer 1 according to Supplementary Note 3 will be described.

[0260] Note 3-1

[0261] The inkjet printer 1 involved in Note 3-1 is characterized in that it comprises: a liquid ejection unit 3, which ejects ink cured by ultraviolet irradiation to the recording paper PP; an ultraviolet irradiation unit 5C, which irradiates the ink ejected onto the recording paper PP with ultraviolet rays; a slide 110, which carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5C in a manner arranged in the Y1 direction and moves them in the Y1 direction on the recording paper PP; and a slide conveying motor 91, which is used to move the slide 110, and the ultraviolet irradiation unit 5C comprises: an ultraviolet light source E, which emits ultraviolet rays; a wall 601B, which is located between the ultraviolet light source E and the liquid ejection unit 3; and a wall 602, which is located on the opposite side of the wall 601B across the ultraviolet light source E, and the light absorption rate of the wall 602 is higher than the light absorption rate of the wall 601B.

[0262] In Supplementary Note 3, the wall surface 601B is an example of a “first wall surface”, the wall surface 602 is an example of a “second wall surface”, and the Y1 direction is an example of a “first direction”.

[0263] According to Supplementary Note 3-1, since the light absorptivity of wall surface 602 is higher than that of wall surface 601B, the intensity of ultraviolet light reaching liquid ejection unit 3 can be suppressed to a lower level compared to a solution in which the light absorptivity of wall surface 602 is lower than that of wall surface 601B. Therefore, according to Supplementary Note 3-1, ink solidification can be suppressed in liquid ejection unit 3, reducing the occurrence of abnormal ink ejection in liquid ejection unit 3.

[0264] Note 3-2

[0265] The inkjet printer 1 according to Supplementary Note 3-2 is characterized in that, in the inkjet printer 1 according to Supplementary Note 3-1, the wall surface 601B is a mirror surface, and the wall surface 602 is not a mirror surface.

[0266] According to Supplementary Note 3-2, the illumination intensity of ultraviolet rays reaching the liquid ejection unit 3 can be suppressed to a low level compared to a case where the wall surface 602 is a mirror surface.

[0267] Note 3-3

[0268] The inkjet printer 1 involved in Note 3-3 is characterized in that, in the inkjet printer 1 involved in Note 3-1 or Note 3-2, the ultraviolet light source E includes: a light-emitting portion 81 that emits ultraviolet rays; and a lens portion 82 that seals the light-emitting portion 81, and the height of the lens portion 82 is larger than the diameter of the lens portion 82.

[0269] According to Supplementary Note 3-3, the directivity of the ultraviolet light emitted from the ultraviolet light source E can be improved compared to a configuration in which the height of the lens portion 82 is less than the diameter of the lens portion 82. Therefore, according to Supplementary Note 3-3, the illuminance of the ultraviolet light reaching the liquid ejection unit 3 can be suppressed to a low level.

[0270] Notes 3-4

[0271] The inkjet printer 1 involved in Note 3-4 is characterized in that, in the inkjet printer 1 involved in Notes 3-1 to 3-3, the liquid ejection unit 3 ejects ink in the Z1 direction intersecting the Y1 direction, and the wall 601B is set to be longer than the distance dY1 between the wall 601B and the liquid ejection unit 3 in the Y1 direction when the distance in the Z1 direction from the substrate 51 on which the ultraviolet light source E is provided is the distance dZ1, and the distance dY2 between the wall 601B and the liquid ejection unit 3 in the Y1 direction when the distance in the Z1 direction from the substrate 51 is the distance dZ2 longer than the distance dZ1.

[0272] In Supplementary Note 3, the distance dZ1 is an example of the “first distance”, the distance dZ2 is an example of the “second distance”, and the Z1 direction is an example of the “second direction”.

[0273] According to Supplementary Note 3-4, since the wall surface 601B is arranged to expand in the Y1 direction as it goes in the Z1 direction, the amount of ultraviolet rays irradiated from the ultraviolet irradiation unit 5C to the recording paper PP can be increased compared to a solution in which the wall surface 601B is not arranged to expand in the Y1 direction.

[0274] Notes 3-5

[0275] The inkjet printer 1 according to Supplement 3-5 is characterized in that, in the inkjet printer 1 according to Supplement 3-1 to Supplement 3-4, when the ultraviolet irradiation unit 5C is cross-sectionally viewed in a direction perpendicular to the Y1 direction and the Z1 direction, the angle formed between the extension direction of the wall surface 601B and the Z1 direction is not less than 0 degrees and not more than 30 degrees. In other words, the inkjet printer 1 according to Supplement 3-5 is characterized in that, in the inkjet printer 1 according to Supplement 3-1 to Supplement 3-4, the angle formed between the normal direction of the wall surface 601B and the Z1 direction is not less than 60 degrees and not more than 90 degrees.

[0276] According to Supplementary Note 3-5, the amount of ultraviolet rays irradiated from the ultraviolet irradiation unit 5C to the recording paper PP can be increased compared to when the angle between the extending direction of the wall surface 601B and the Z1 direction is less than 0 degrees or greater than 30 degrees.

[0277] Notes 3-6

[0278] The inkjet printer 1 according to Supplement 3-6 is characterized in that, in the inkjet printer 1 according to Supplement 3-1 to Supplement 3-5, the ultraviolet irradiation unit 5C includes a cover plate 502 provided between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0279] According to Supplementary Note 3-6, since the cover plate 502 suppresses the adhesion of ink to the ultraviolet light source E, it is possible to suppress a reduction in the illuminance of the ultraviolet irradiation unit 5C due to the adhesion of ink to the lens portion 82 .

[0280] Notes 3-7

[0281] The inkjet printer 1 according to Supplementary Note 3-7 is characterized in that, in the inkjet printer 1 according to Supplementary Note 3-6, the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5C.

[0282] According to Note 3-7, in cases where ink adheres to the cover 502 and the ink solidifies, the ultraviolet irradiation unit 5C can be replaced by only the cover 502 without disassembling the ultraviolet irradiation unit 5C. Therefore, the maintainability of the ultraviolet irradiation unit 5C is improved compared to a solution in which the cover 502 cannot be replaced.

[0283] E.4. Note 4

[0284] Hereinafter, the inkjet printer 1 according to Supplementary Note 4 will be described.

[0285] Appendix 4-1

[0286] The inkjet printer 1 involved in Note 4-1 is characterized in that it includes: a liquid ejection unit 3 for ejecting ink cured by ultraviolet irradiation onto the recording paper PP; an ultraviolet irradiation unit 5B for irradiating the ink ejected onto the recording paper PP with ultraviolet rays; a carriage 110 for carrying the liquid ejection unit 3 and the ultraviolet irradiation unit 5B in a manner arranged in the Y1 direction and moving them in the Y1 direction on the recording paper PP; and a carriage conveying motor 91 for moving the carriage 110, the distance between the ultraviolet irradiation unit 5B and the recording paper PP is not less than 1 mm and not more than 15 mm, the ultraviolet irradiation unit 5B includes: an ultraviolet light source E for emitting ultraviolet rays in the Z1 direction intersecting the Y1 direction; and a wall 601B for reflecting at least a portion of the ultraviolet rays emitted from the ultraviolet light source E, and when the ultraviolet irradiation unit 5B is cross-sectionally viewed in a direction perpendicular to the Y1 direction and the Z1 direction, the angle formed by the extension direction of the wall 601B and the Z1 direction is not less than 5 degrees and not more than 15 degrees.

[0287] In addition, in Supplementary Note 4, the wall surface 601B is an example of a “reflection surface”, the Y1 direction is an example of a “first direction”, and the Z1 direction is an example of a “second direction”.

[0288] According to Supplementary Note 4-1, since the angle formed between the extension direction of the wall surface 601B and the Z1 direction is between 5 degrees and 15 degrees, the efficiency of ultraviolet light irradiation from the ultraviolet irradiation unit 5B to the recording paper PP can be improved compared to a case where the angle formed between the extension direction of the wall surface 601B and the Z1 direction is less than 5 degrees. Furthermore, according to Supplementary Note 4-1, since the angle formed between the extension direction of the wall surface 601B and the Z1 direction is between 5 degrees and 15 degrees, the maximum intensity of ultraviolet light irradiation from the ultraviolet irradiation unit 5B to the recording paper PP can be increased compared to a case where the angle formed between the extension direction of the wall surface 601B and the Z1 direction is greater than 15 degrees. In other words, according to Supplementary Note 4-1, both the maximum intensity of ultraviolet light irradiation from the ultraviolet irradiation unit 5B to the recording paper PP and the efficiency of ultraviolet light irradiation from the ultraviolet irradiation unit 5B to the recording paper PP can be improved.

[0289] Appendix 4-2

[0290] The inkjet printer 1 involved in Note 4-2 is characterized in that, in the inkjet printer 1 involved in Note 4-1, when the ultraviolet irradiation unit 5B is cross-sectioned in a direction perpendicular to the Y1 direction and the Z1 direction, the angle formed by the extension direction of the wall 601B and the Z1 direction is greater than 5 degrees and less than 10 degrees.

[0291] According to Supplementary Note 4-2, it is possible to achieve both an increase in the maximum illuminance of ultraviolet rays from the ultraviolet irradiation unit 5B on the recording paper PP and an increase in the efficiency of ultraviolet rays irradiation from the ultraviolet irradiation unit 5B on the recording paper PP.

[0292] Note 4-3

[0293] The inkjet printer 1 involved in Note 4-3 is characterized in that, in the inkjet printer 1 involved in Note 4-1 or Note 4-2, the ultraviolet light source E includes: a light-emitting portion 81 that emits ultraviolet rays; and a lens portion 82 that seals the light-emitting portion 81, and the height of the lens portion 82 is larger than the diameter of the lens portion 82.

[0294] According to Supplementary Note 4-3, the directivity of the ultraviolet rays emitted from the ultraviolet light source E can be improved compared to a case where the height of the lens portion 82 is equal to or smaller than the diameter of the lens portion 82 .

[0295] Note 4-4

[0296] The inkjet printer 1 according to Supplementary Note 4-4 is characterized in that the inkjet printer 1 according to Supplementary Notes 4-1 to 4-3 includes a rubber member, and the wavelength of ultraviolet rays emitted from the ultraviolet light source E is 250 nm to 410 nm.

[0297] In addition, in Supplementary Note 4, a rubber component is an example of a “specific component”.

[0298] According to Supplementary Note 4-4, the possibility of ultraviolet rays emitted from the ultraviolet light source E reacting with oxygen in the air to generate ozone can be reduced compared to the embodiment in which ultraviolet rays with a wavelength of 100 nm to 230 nm are irradiated from the ultraviolet light source E. Therefore, according to Supplementary Note 4-4, the degradation of rubber components can be suppressed.

[0299] Notes 4-5

[0300] The inkjet printer 1 according to Supplement 4-5 is characterized in that, in the inkjet printer 1 according to Supplement 4-1 to Supplement 4-4, the ultraviolet irradiation unit 5B includes a cover plate 502 provided between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0301] According to Supplementary Note 4-5, since the cover plate 502 suppresses adhesion of ink to the ultraviolet light source E, a decrease in the illuminance of the ultraviolet irradiation unit 5B due to adhesion of ink to the ultraviolet light source E can be suppressed.

[0302] Notes 4-6

[0303] The inkjet printer 1 according to Supplementary Note 4-6 is characterized in that, in the inkjet printer 1 according to Supplementary Note 4-5, the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5B.

[0304] According to Supplementary Note 4-6, since only the cover plate 502 can be replaced without disassembling the ultraviolet irradiation unit 5B, the maintainability of the ultraviolet irradiation unit 5B is improved compared to a solution in which the cover plate 502 cannot be replaced.

[0305] E.5. Note 5

[0306] Hereinafter, the inkjet printer 1 according to Supplementary Note 5 will be described.

[0307] Appendix 5-1

[0308] The inkjet printer 1 involved in Note 5-1 includes: a liquid ejection unit 3, which ejects ink cured by ultraviolet irradiation onto the recording paper PP; an ultraviolet irradiation unit 5, which irradiates the ink ejected onto the recording paper PP with ultraviolet rays; a carriage 110, which carries the liquid ejection unit 3 and the ultraviolet irradiation unit 5 in a manner arranged in the Y1 direction and moves them in the Y1 direction on the recording paper PP; and a carriage conveying motor 91, which is used to move the carriage 110, the ultraviolet irradiation unit 5 includes a plurality of ultraviolet light sources E that emit ultraviolet rays in a Z1 direction intersecting the Y1 direction, one of the plurality of ultraviolet light sources E includes: a light emitting portion 81 that emits ultraviolet rays; and a lens portion 82 that seals the light emitting portion 81, the lens portion 82 includes: a cylindrical base portion 821, and a hemispherical front end portion 822 connected to the base portion 821 in the Z1 direction, the height dEZ of the lens portion 82 in the Z1 direction being longer than the diameter of the base portion 821, that is, the width dEY.

[0309] Furthermore, in Supplementary Note 5, one ultraviolet light source E is an example of a “first ultraviolet light source”, the Y1 direction is an example of a “first direction”, and the Z1 direction is an example of a “second direction”.

[0310] According to Supplementary Note 5-1, the directivity of the ultraviolet rays emitted from a single ultraviolet light source E can be improved compared to a configuration in which the height dEZ of the lens portion 82 in the Z1 direction is less than or equal to the diameter of the base portion 821. Therefore, according to Supplementary Note 5-1, the irradiation efficiency of the ultraviolet rays from the ultraviolet irradiation unit 5 can be improved compared to a configuration in which the height dEZ of the lens portion 82 in the Z1 direction is less than or equal to the diameter of the base portion 821. Furthermore, the possibility that the ultraviolet rays emitted from the ultraviolet irradiation unit 5 will be reflected by the recording paper PP and reach the liquid ejection unit 3 can be reduced.

[0311] Appendix 5-2

[0312] The inkjet printer 1 involved in Note 5-2 is characterized in that, in the inkjet printer 1 involved in Note 5-1, the plurality of ultraviolet light sources E are arranged in an X1 direction intersecting the Y1 direction and the Z1 direction, and the interval dLY between two adjacent ultraviolet light sources E in the Y1 direction among the plurality of ultraviolet light sources E is greater than the interval dLX between two adjacent ultraviolet light sources E in the X1 direction among the plurality of ultraviolet light sources E.

[0313] Furthermore, in Supplementary Note 5, the X1 direction is an example of the “third direction”.

[0314] According to Supplementary Note 5-2, since the interval dLX is less than the interval dLY, unevenness in the illumination intensity of the ultraviolet light source E in the X1 direction can be reduced. Therefore, according to Supplementary Note 5-2, even when the carriage 110 carrying the ultraviolet irradiation unit 5 moves in the Y1 direction, the ultraviolet irradiation unit 5 can irradiate the recording paper PP with ultraviolet rays at a uniform intensity.

[0315] Appendix 5-3

[0316] The inkjet printer 1 involved in Note 5-3 is characterized in that, in the inkjet printer 1 involved in Note 5-1 or Note 5-2, one ultraviolet light source E is adjacent to other ultraviolet light sources E among the multiple ultraviolet light sources E in the X1 direction, and the irradiation range on the recording paper PP of the ultraviolet rays emitted from one ultraviolet light source E overlaps with the irradiation range on the recording paper PP of the ultraviolet rays emitted from other ultraviolet light sources E.

[0317] In addition, in Supplementary Note 5, the other ultraviolet light source E is an example of a “second ultraviolet light source”.

[0318] According to Supplementary Note 5-3, since the irradiation range of ultraviolet rays on the recording paper PP of one ultraviolet light source E and another ultraviolet light source E overlap, unevenness in illumination of the ultraviolet light source E in the X1 direction can be reduced.

[0319] Note 5-4

[0320] The inkjet printer 1 according to Supplementary Note 5-4 is characterized in that the inkjet printer 1 according to Supplementary Notes 5-1 to 5-3 includes a rubber member, and the wavelength of ultraviolet rays emitted from the ultraviolet light source E is 250 nm to 410 nm.

[0321] In addition, in Supplementary Note 5, a rubber component is an example of a “specific component”.

[0322] According to Supplementary Note 5-4, the possibility of ultraviolet light emitted from the ultraviolet light source E reacting with oxygen in the air to generate ozone can be reduced compared to the embodiment in which ultraviolet light of 100 nm to 230 nm is irradiated from the ultraviolet light source E. Therefore, according to Supplementary Note 5-4, the degradation of rubber parts can be suppressed.

[0323] Note 5-5

[0324] The inkjet printer 1 according to Supplementary Note 5 - 5 is characterized in that the ultraviolet irradiation unit 5 includes a heat sink 52 for cooling the plurality of ultraviolet light sources E in the inkjet printer 1 according to Supplementary Notes 5 - 1 to 5 - 4 .

[0325] According to Supplementary Note 5-5, since the ultraviolet irradiation unit 5 includes the heat sink 52, the service life of the plurality of ultraviolet light sources E can be extended compared to a solution in which the ultraviolet irradiation unit 5 does not include the heat sink 52. Therefore, according to Supplementary Note 5-5, in order to prevent the irradiation intensity of the ultraviolet rays from the ultraviolet irradiation unit 5 from deviating from the desired intensity due to malfunction of some of the plurality of ultraviolet light sources E, the possibility of replacing all of the plurality of ultraviolet light sources E can be reduced.

[0326] Notes 5-6

[0327] The inkjet printer 1 according to Supplementary Note 5-6 is characterized in that, in the inkjet printer 1 according to Supplementary Notes 5-1 to 5-5, the ultraviolet irradiation unit 5 includes a cover plate 502 provided between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0328] According to Supplementary Note 5-6, since the cover plate 502 can suppress the adhesion of ink to the ultraviolet light source E, the reduction in the illuminance of the ultraviolet irradiation unit 5 due to the adhesion of ink to the ultraviolet light source E can be suppressed.

[0329] Notes 5-7

[0330] The inkjet printer 1 according to Supplementary Note 5-7 is characterized in that, in the inkjet printer 1 according to Supplementary Notes 5-1 to 5-6, the cover plate 502 can be replaced without removing the ultraviolet light source E from the ultraviolet irradiation unit 5 .

[0331] According to Supplementary Note 5-7, since only the cover plate 502 can be replaced without disassembling the ultraviolet irradiation unit 5, the maintainability of the ultraviolet irradiation unit 5 is improved compared with a solution in which the cover plate 502 cannot be replaced.

Claims

1. A liquid ejection device, characterized in that: have: A liquid ejecting unit ejects the liquid solidified by ultraviolet irradiation onto the medium; an irradiation unit for irradiating the liquid sprayed onto the medium with ultraviolet rays; a carriage carrying the liquid ejecting unit and the irradiation unit and moving on the medium; and a motor for moving the carriage, The irradiation unit comprises: substrate; and an ultraviolet light source, disposed on the substrate and emitting ultraviolet light, The substrate has a base material made of aluminum.

2. The liquid ejection device according to claim 1, wherein At least a portion of the heat generated in the ultraviolet light source is dissipated through the substrate.

3. The liquid ejection device according to claim 1, wherein The surface area of ​​the base material is larger than the area of ​​a region of the substrate where the ultraviolet light source is provided.

4. The liquid ejection device according to claim 1, wherein An aluminum heat sink is mounted on the substrate.

5. The liquid ejection device according to claim 1, wherein The ultraviolet light source is a light emitting diode that emits ultraviolet rays.

6. The liquid ejection device according to claim 1, wherein A temperature sensor is provided on the substrate.

7. The liquid ejection device according to claim 6, wherein: The substrate is provided with a signal conversion circuit for converting the output from the temperature sensor into a digital signal. The temperature sensor and the signal conversion circuit are packaged as an integrated circuit.

8. The liquid ejection device according to claim 1, wherein: The irradiation unit includes a housing including a cover plate and a frame for transmitting ultraviolet rays. The substrate and the ultraviolet light source are disposed in the housing.

9. An ultraviolet irradiation device, characterized in that: Set in the liquid ejection device, The liquid ejection device comprises: A liquid ejecting unit ejects the liquid solidified by ultraviolet irradiation onto the medium; a carriage, carrying the liquid ejecting unit and moving on the medium; as well as a motor for moving the carriage, The ultraviolet irradiation device is mounted on the carriage and irradiates the liquid ejected onto the medium with ultraviolet rays. The ultraviolet irradiation device comprises: substrate; and an ultraviolet light source, disposed on the substrate and emitting ultraviolet light, The substrate has a base material made of aluminum.

10. The ultraviolet irradiation device according to claim 9, characterized in that At least a portion of the heat generated in the ultraviolet light source is dissipated through the substrate.

11. The ultraviolet irradiation device according to claim 9, characterized in that The surface area of ​​the base material is larger than the area of ​​a region of the substrate where the ultraviolet light source is provided.

12. The ultraviolet irradiation device according to claim 9, characterized in that An aluminum heat sink is mounted on the substrate.

13. The ultraviolet irradiation device according to claim 9, characterized in that The ultraviolet light source is a light emitting diode that emits ultraviolet rays.

14. The ultraviolet irradiation device according to claim 9, characterized in that A temperature sensor is provided on the substrate.

15. The ultraviolet irradiation device according to claim 14, characterized in that The substrate is provided with a signal conversion circuit for converting the output from the temperature sensor into a digital signal. The temperature sensor and the signal conversion circuit are packaged as an integrated circuit.

16. The ultraviolet irradiation device according to claim 9, characterized in that The ultraviolet irradiation device includes a housing including a cover plate and a frame for transmitting ultraviolet rays. The substrate and the ultraviolet light source are disposed in the housing.

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