Liquid ejecting apparatus and ultraviolet irradiation apparatus

Abstract

The invention provides a liquid ejecting apparatus and an ultraviolet irradiation apparatus. Ultraviolet rays are efficiently irradiated from an irradiation unit. 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 ejection unit and the irradiation unit are mounted so as to be aligned in the first direction and which moves in the first direction on the medium; the distance between the irradiation unit and the medium is more than 1 mm and less than 15 mm, and the irradiation unit is provided with an ultraviolet light source which emits ultraviolet light in a second direction which intersects with the first direction; and a reflecting surface that reflects at least a portion of the ultraviolet light emitted from the ultraviolet light source, and when the irradiation unit is viewed in a cross-sectional view in a direction perpendicular to the first direction and the second direction, the angle formed by the extending direction of the reflecting surface and the second direction is 5-15 degrees.

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-curing ink (an example of a "liquid") that cures by irradiation with ultraviolet light onto a medium. For example, Patent Document 1 discloses a liquid ejection device comprising: a liquid ejection unit that ejects ultraviolet-curing ink onto a medium; an irradiation unit that irradiates the liquid ejected onto the medium with ultraviolet light; a carriage that carries the liquid ejection unit and the irradiation unit and moves over the medium; and a motor that moves the carriage.

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

[0004] However, according to the conventional technology, there are cases where the ultraviolet rays irradiated from the irradiation unit are widely diffused, and the liquid discharged onto the medium cannot be efficiently irradiated with the ultraviolet rays. Summary of the Invention

[0005] In order to solve the above technical 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 onto 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 in a manner arranged in a first direction and moves in the first direction on the medium; and a motor for moving the slide, the distance between the irradiation unit and the medium is greater than 1 mm and less than 15 mm, and the irradiation unit comprises: an ultraviolet light source, which emits ultraviolet light in a second direction intersecting the first direction; and a reflecting surface, which reflects at least a portion of the ultraviolet light emitted from the ultraviolet light source, when the irradiation unit is viewed in a cross-section in a direction perpendicular to the first direction and the second direction, the angle formed by the extension direction of the reflecting surface and the second direction is greater than 5 degrees and less than 15 degrees.

[0006] In addition, the ultraviolet irradiation device involved in the present invention is characterized in that the ultraviolet irradiation device is arranged in a liquid ejecting device, and the liquid ejecting device comprises: a liquid ejecting unit, which ejects liquid cured by ultraviolet irradiation onto a medium; a slide, which carries the liquid ejecting unit and moves in the first direction on the medium; and a motor for moving the slide, the ultraviolet irradiation device is mounted on the slide in a manner aligned with the liquid ejecting unit in the first direction, and irradiates ultraviolet light on the liquid ejected onto the medium, the distance between the ultraviolet irradiation device and the medium is greater than 1 mm and less than 15 mm, the ultraviolet irradiation device comprises: an ultraviolet light source, which emits ultraviolet light in a second direction intersecting the first direction; and a reflecting surface, which reflects at least a portion of the ultraviolet light emitted from the ultraviolet light source, when the ultraviolet irradiation device is viewed in a cross-section in a direction perpendicular to the first direction and the second direction, the angle formed by the extension direction of the reflecting surface and the second direction is greater than 5 degrees and less than 15 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a block diagram showing an example of the configuration of the ink jet 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 It 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 103 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 This 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 27This 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…Frame, 51…Substrate, 52…Radiator, 53…Lubricant, 54…Metal plating, 61…Wall, 62…Wall, 71…Semiconductor temperature sensor, 72…Signal conversion circuit, 81…Light emitting unit, 82…Lens, 83…Encapsulation unit, 84…Connecting wiring unit, 91…Slide transport motor, 92…Media transport motor, 95…Press plate, 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] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the figures, the dimensions and scales of the various components may differ from actual dimensions as appropriate. Furthermore, the embodiments described below are preferred specific examples of the present invention and, therefore, are subject to various technically preferred limitations. However, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0038] A. First embodiment

[0039] In the first embodiment, an inkjet printer 1 that discharges ink onto recording paper PP to form an image is taken as an example to describe the liquid discharge device.

[0040] A.1. Overview of inkjet printers

[0041] Below, refer to Figures 1 to 4 An example of the configuration 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 1As shown, print data Img representing an image to be formed by inkjet printer 1 is supplied from a host computer such as a personal computer or a digital camera to inkjet printer 1. Inkjet printer 1 executes a print process to form the image represented by 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 part 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 part 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] Note that, 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] It should be noted that, 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 may be made focusing on the liquid ejection unit 3 among the four liquid ejection units 3 and one drive signal generation unit 4 provided corresponding to one liquid ejection unit 3 among the four drive signal generation units 4 .

[0048] The control unit 2 is configured to include one or more CPUs (Central Processing Units). However, the control unit 2 may also be configured to include a programmable logic device such as an FPGA (field-programmable gate array) instead of a CPU, or to include a programmable logic device such as an FPGA in addition to a CPU. Furthermore, the control unit 2 includes a memory. The memory is configured to include one or both of a volatile memory such as RAM (Random Access Memory) and a 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 each unit 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 printing, the control unit 2 generates signals such as the designation signal SI for controlling the liquid ejection unit 3 based on the print data Img. Furthermore, when printing, the control unit 2 generates signals such as the waveform designation signal dCom for controlling the drive signal generation unit 4. Furthermore, when printing, the control unit 2 generates signals such as the carriage transport control signal SK and the medium transport control signal SB for controlling the transport unit 9. Thus, during printing, the control unit 2 controls the transport unit 9 to move the liquid ejection unit 3 and the recording paper PP, and adjusts the presence or absence of ink ejection from the ejection unit D and the timing of ink ejection, thereby controlling the various components of the inkjet printer 1 so that an image corresponding to the print data Img is formed 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." It should be noted that, 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]. Here, the variable m is a natural number satisfying "1 ≤ m ≤ M." Furthermore, 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 reference numerals representing such component or signal may be annotated with "[m]."

[0054] The supply circuit 31 switches whether to supply the drive signal Com to the discharge portion D[m] based on the designation signal SI. Hereinafter, the drive signal Com supplied to the discharge 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] It should be noted that 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 with the method of irradiating ultraviolet light with a wavelength of 100 nm to 230 nm 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 to generate ozone can be reduced.

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

[0059] The temperature detection integrated circuit 7 detects the temperature inside the ultraviolet irradiation unit 5 and outputs a temperature detection signal DT, which is 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] It should be noted that 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, when the light source control signal SL specifies on, the ultraviolet light source module 6 turns on the ultraviolet light source E, and when the light source control signal SL specifies off, the ultraviolet light source module 6 turns off the ultraviolet light source E.

[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 to be 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 2 As shown, in the first embodiment, the inkjet printer 1 is assumed to be a serial printer. Specifically, when printing, the inkjet printer 1 ejects ink from the liquid ejection unit 3 while conveying the recording paper PP in the X1 direction and moving the liquid ejection unit 3 in the Y1 direction intersecting the X1 direction, thereby forming an image corresponding to the print data Img on the recording paper PP. Furthermore, when printing, the inkjet printer 1 solidifies the ink ejected onto the recording paper PP by irradiating the recording paper PP with ultraviolet light while moving the ultraviolet irradiation unit 5 in the Y1 direction.

[0066] It should be noted that 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, and the liquid ejection unit 3 is moved 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, and the ultraviolet irradiation unit 5 is moved in the Y2 direction.

[0067] Hereinafter, the X1 direction and the X2 direction, which is its opposite direction, will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and the Y2 direction, which is its opposite direction, 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 its opposite direction, will be collectively referred to as the "Z-axis direction." In the first embodiment, as an example, the X-axis direction, the Y-axis direction, and the Z-axis direction are described as being orthogonal to each other. However, the present invention is not limited to this embodiment. The X-axis direction, the Y-axis direction, and the Z-axis direction may be any direction that intersects each other. It should be noted that 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 2 As shown, the carriage 110 is assumed to be equipped with four ink cartridges 120 corresponding one-to-one to the four ink colors of cyan, magenta, yellow, and black. Furthermore, in the first embodiment, as described above, the carriage 110 is assumed to be equipped with four liquid ejection units 3 corresponding one-to-one to the four ink cartridges 120. Each ejection portion D[m] receives ink supplied 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]. It should be noted that the ink cartridges 120 may also be located external to the carriage 110.

[0070] Furthermore, as described above, the inkjet printer 1 according to the first embodiment includes the transport unit 9. Figure 2As 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 supporting the carriage 110 so that it can reciprocate freely 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 can reciprocate the liquid ejection unit 3 along with the carriage 110 in the Y-axis direction along the carriage guide shaft 96, while the media transport motor 92 can transport 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, allowing 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 4 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 and lower electrodes Zu[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 response to the applied voltage, causing the piezoelectric element PZ[m] to vibrate. The lower electrode Zd[m] is bonded 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. Furthermore, due to the vibration of the vibration plate 321, the volume of the cavity CV and the pressure within the cavity CV change, 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 from above in the Z2 direction.

[0075] like Figure 4 As illustrated, the ultraviolet irradiation unit 5 and the four liquid ejection units 3 are mounted on the carriage 110 so as to be aligned in the Y1 direction. Specifically, the first embodiment assumes that the ultraviolet irradiation unit 5 and the four liquid ejection units 3 are mounted on the carriage 110 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 performing a printing process, immediately after the ink ejected by the liquid ejection unit 3 while moving in the Y1 direction adheres to the recording paper PP, the ultraviolet irradiation unit 5 can cure the ink ejected onto the recording paper PP by irradiating it with ultraviolet light while moving in the Y1 direction.

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

[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, a case is envisioned where the ultraviolet light source module 6 is disposed between the temperature detection integrated circuit 7 and the liquid ejection unit 3 on 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 on 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, a case is assumed in which the ultraviolet light source module 6 includes 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, a case is assumed in which the value NY is "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, a case is envisioned where the interval dLX is less than the interval dLY. That is, in the first embodiment, as an example, a case is envisioned where 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. It should be noted that the "interval between two adjacent ultraviolet light sources E" may also be the distance between the center of one of the two ultraviolet light sources E and the center of the other ultraviolet light source E when the carriage 110 is viewed from above in the Z2 direction, or may be the shortest distance between one of the two ultraviolet light sources E and the other ultraviolet light source E.

[0080] like Figure 4As illustrated, the first embodiment assumes a case where the temperature detection integrated circuit 7 is positioned midway along the X-axis within the ultraviolet irradiation unit 5. More specifically, the first embodiment assumes a case where the temperature detection integrated circuit 7 is positioned approximately the same distance in the X-axis direction as the X1 end of the arrangement region of the multiple ultraviolet light sources E within the ultraviolet irradiation unit 5 and the X2 end of the arrangement region of the multiple ultraviolet light sources E within the ultraviolet irradiation unit 5. "Approximately the same" here encompasses not only cases of being completely identical but also cases where errors are considered to be the same. For example, this includes cases where the design is identical but differ due to manufacturing errors, and cases where the specifications are identical but differ due to errors caused by interference, etc. In the first embodiment, "approximately the same" is a concept that includes cases where errors of approximately 10% are considered to be the same.

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

[0082] Below, refer to Figure 5 and Figure 6 The configuration of the ultraviolet irradiation unit 5 will be 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, as well as various wirings 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-transmitting 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 materials other than glass, such as ultraviolet-transmitting transparent resin.

[0090] It should be noted that in the first embodiment, the cover plate 502 is configured to be freely removable and attachable to the frame 501. Specifically, in the first embodiment, while the ultraviolet irradiation unit 5 is installed in the inkjet printer 1, 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. Therefore, according to the first embodiment, the cover plate 502 can be easily replaced in situations such as when ink adheres to the cover plate 502 or when the intensity of ultraviolet rays irradiating the recording paper PP from the ultraviolet light source E decreases. This improves the maintainability of the ultraviolet irradiation unit 5 compared to a system 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. It should be noted that in the first embodiment, the following scenario is envisioned: 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 from sponge prevents the ink mist from intruding into the interior of the cover plate 502, reducing the likelihood of the mist contacting the ultraviolet light sources E. More specifically, in the first embodiment, the wall surfaces 601 and 602 are formed from silicone sponge. This improves the heat resistance of the wall surfaces 601 and 602 and makes them flame-retardant, making them a preferred configuration for environments where ultraviolet light is irradiated from the ultraviolet light sources E. Furthermore, 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 viewed in cross section 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] It should be noted that in the first embodiment, the ultraviolet irradiation unit 5 is positioned at a distance of at least 1 mm and no greater than 15 mm from the recording paper PP in the Z-axis direction. Therefore, according to the first embodiment, the distance between the ultraviolet irradiation unit 5 and the recording paper PP is maintained at a distance of at least 1 mm, thereby reducing the risk of contact between the ultraviolet irradiation unit 5 and the recording paper PP. Furthermore, according to the first embodiment, the distance between the ultraviolet irradiation unit 5 and the recording paper PP is maintained at a distance of no greater than 15 mm, thereby ensuring the intensity of the ultraviolet rays irradiated from the ultraviolet irradiation unit 5 to the recording paper PP.

[0094] Furthermore, in the first embodiment, the plurality of ultraviolet light sources E are arranged so that, with respect to two ultraviolet light sources E adjacent to each other in the Y-axis direction among the plurality of ultraviolet light sources E provided in the ultraviolet irradiation unit 5, the irradiation range of the ultraviolet light on the recording paper PP emitted by one ultraviolet light source E overlaps with the irradiation range of the ultraviolet light on the recording paper PP emitted by the other ultraviolet light source E. Similarly, in the first embodiment, the plurality of ultraviolet light sources E are arranged so that, with respect to two ultraviolet light sources E adjacent to each other in the X-axis direction among the plurality of ultraviolet light sources E provided in the ultraviolet irradiation unit 5, the irradiation range of the ultraviolet light on the recording paper PP emitted by one ultraviolet light source E overlaps with the irradiation range of the ultraviolet light on the recording paper PP emitted by the other ultraviolet light source E.

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

[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) emitting ultraviolet light is assumed 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. Furthermore, holes supplied from one connecting wiring section 84 and electrons supplied from the other connecting wiring section 84 couple in the light-emitting section 81, causing the light-emitting section 81 to emit light and 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 assumed to be 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 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 wiring 514 electrically connected to another connecting wiring portion 84. It should be noted that in the first embodiment, a case where the metal plating layer 54 is disposed between the ultraviolet light source E and the substrate 51 is envisioned. Furthermore, in the first embodiment, a case where one connecting wiring portion 84 is electrically connected to one wiring 514 via the metal plating layer 54, and another connecting wiring portion 84 is electrically connected to the other wiring 514 via the metal plating layer 54 is envisioned.

[0102] The resist 513 electrically insulates one wiring 514 from the other wirings 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, the heat sink 52 is assumed to be connected to the base material 511 via the lubricating oil 53. However, the heat sink 52 may be connected to the base material 511 via a heat dissipation fin.

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

[0106] It should be noted that 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 7 and Figure 8 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 depending on 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] It should be noted that, 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 represents the temperature TE of the ultraviolet light source E, and the vertical axis represents 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. In other words, in the first embodiment, the temperature TE of the ultraviolet light source E and the radiant flux RE of ultraviolet rays emitted from the ultraviolet light source E have a negative correlation.

[0116] In addition, 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 within the ultraviolet irradiation unit 5 in which the ultraviolet light source E is located. Therefore, for example, if the temperature within the ultraviolet light source E exceeds the appropriate temperature, the intensity of the ultraviolet rays emitted from the ultraviolet light source E will fall below the appropriate intensity. Consequently, for example, if the temperature within the ultraviolet light source E exceeds the appropriate temperature, the ultraviolet rays from the ultraviolet irradiation unit 5 may not be irradiated onto the recording paper PP with the appropriate intensity, and the image quality of the image formed on the recording paper PP may be degraded.

[0118] In response to this, 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 of the image quality 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 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 Y-axis position of the central axis AX representing the center portion of the ultraviolet light source module 6 is set to "Y = 0," the Y-axis position of the end of the cover plate 502 in the Y1 direction is set to "Y = L," and the Y-axis position of the end of the cover plate 502 in the Y2 direction is set to "Y = -L." Specifically, the following assumes a case where the width of the cover plate 502 in the Y-axis direction is "2L." Here, the value L is a real number satisfying "L > 0." Furthermore, in the illumination simulation, the case of "L = 12.5 mm," or "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 in the Z1 direction of the cover plate 502 is referred to as the unit length HW. In the illumination simulation, a case where the unit length HW is 8.1 mm is assumed.

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

[0125] The illumination simulation assumes that the value NY is “4” and the value NX is “16.” That is, the illumination simulation assumes that 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 was assumed that the total amount of ultraviolet rays emitted for one second from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 was “83 W”.

[0127] In the illumination simulation, a case where the distance dLX is “4.4 mm” and the distance dLY is “4.6 mm” was assumed.

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

[0129] Figure 10 : is a diagram showing the results of the illumination simulation according to the first embodiment. Specifically, Figure 10 is a graph showing the illuminance of ultraviolet rays, which are Figure 9 Under the illumination simulation conditions shown, when the recording paper PP placed on the platen 95 is cut by a plane whose normal direction is the X-axis direction, ultraviolet rays are irradiated on the cut surface (hereinafter referred to as the "cut surface of interest"). 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 on the recording paper PP is "5.2 W / cm 2 ", focusing on the range of ultraviolet rays reaching the cut surface, which is from "-1.18 L" to "1.18 L". In addition, in the first illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5 for 1 second is "62 W".

[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 an ultraviolet irradiation unit according to a conventional example will be described.

[0133] Figure 11 The diagrams show the outlines of the ultraviolet irradiation unit 5 according to the first embodiment, the ultraviolet irradiation unit according to Conventional Example 1, and the ultraviolet irradiation unit according to Conventional Example 2. It should be noted that 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 lot of power, similarly to the ultraviolet irradiation unit according to the conventional example, and it is important to efficiently dissipate heat generated in the ultraviolet irradiation unit 5 .

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

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

[0138] like Figure 12As shown in FIG. 1 , the thermal conductivity of copper is 398 W / mk. Therefore, compared with the thermal conductivity of aluminum (236 W / mk), the thermal conductivity of iron (67 W / mk), and the thermal conductivity of stainless steel (16 W / 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. It should be noted that as materials with higher thermal conductivity than copper, there are also silver with a thermal conductivity of 398 W / mk and diamond with a thermal conductivity of 1000 W / mk. However, due to the high cost of these 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 Compared to conventional ultraviolet irradiation units, aluminum has a smaller specific gravity. Therefore, the ultraviolet irradiation unit 5 according to the first embodiment can achieve lightweighting of the substrate 51, and further lightweighting of the ultraviolet irradiation unit 5, compared to the ultraviolet irradiation unit according to conventional example 1 and the ultraviolet irradiation unit according to conventional example 2. As a result, the ultraviolet irradiation unit 5 according to the first embodiment can reduce the load on 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 according to the first embodiment can extend the life of the carriage conveying motor 91 and reduce the amount of electricity required to drive the carriage conveying motor 91, compared to the method of mounting the ultraviolet irradiation unit according to conventional example 1 or the ultraviolet irradiation unit according to conventional example 2 on the carriage 110.

[0140] Furthermore, as described 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 reduced load on the carriage transport motor 91 that drives the carriage 110 and efficient heat dissipation within the ultraviolet irradiation unit 5.

[0141] In addition, a radiator is usually installed in the ultraviolet irradiation unit that generates a lot of heat to improve the heat dissipation of the ultraviolet irradiation unit. In addition, the radiator is usually made of aluminum. Therefore, as in the ultraviolet irradiation unit involved in the prior art example 1 and the ultraviolet irradiation unit involved in the prior art example 2, when a radiator made of aluminum is installed in the ultraviolet irradiation unit using a copper substrate, the possibility of corrosion occurring at the boundary between the copper substrate and the aluminum becomes high. Therefore, when a radiator made of aluminum is installed in the ultraviolet irradiation unit using a copper substrate as in the prior art example, in order to prevent corrosion at the boundary between the copper substrate and the aluminum radiator, a heat sink is usually provided between the copper substrate and the radiator. Therefore, as in the prior art example, in the ultraviolet irradiation unit using a copper substrate, sometimes the large size of the ultraviolet irradiation unit, the high cost of the ultraviolet irradiation unit, and the increase in the number of parts of the ultraviolet irradiation unit become problems.

[0142] In view of this, the ultraviolet irradiation unit 5 involved in the first embodiment adopts an aluminum substrate in which the base material 511 is formed of aluminum as the substrate 51. Therefore, in the ultraviolet irradiation unit 5 involved in the first embodiment, corrosion at the boundary between the base material 511 formed of aluminum and the heat sink 52 formed of aluminum will not be a problem. Therefore, in the ultraviolet irradiation unit 5 involved in the first embodiment, there is no need to provide a heat sink between the substrate 51 and the heat sink 52, and it is sufficient to provide lubricating oil 53 between the substrate 51 and the heat sink 52. Therefore, the ultraviolet irradiation unit 5 involved in 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 parts of the ultraviolet irradiation unit 5, as compared with the ultraviolet irradiation unit using a copper substrate as in the conventional example.

[0143] It should be noted that aluminum, as a raw metal for metal substrates, has a production volume second only to iron, and its reserves relative to current demand also exceed those of iron. In addition, aluminum is a metal with excellent recyclability compared to copper. On the other hand, the amount of copper resources is limited, and it is expected that by 2050, the amount of copper used will exceed the current reserves. In view of this, 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 the method of using a copper substrate for the ultraviolet irradiation unit 5, the environmental load can be reduced, and it can be said that this method takes into account the future "shortage of copper."

[0144] like Figure 11As 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 traditionally 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 and the liquid ejection unit are mounted together on a carriage, 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] To address this issue, 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 in the ultraviolet irradiation unit 5 according to the first embodiment outputs a digital signal representing the temperature detection result of the ultraviolet irradiation unit 5, namely, a temperature detection signal DT. Therefore, according to the first embodiment, even when the ultraviolet irradiation unit 5 and the liquid discharge unit 3 are mounted together on the carriage 110, 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 discharge unit 3. In other words, according to the first embodiment, the temperature of the ultraviolet irradiation unit 5 can be more accurately determined, compared to conventional methods that use a thermistor as a temperature sensor.

[0146] B. Second embodiment

[0147] Below, refer to Figures 13 to 22 Note that, in the embodiments described below, elements having the same functions and effects as those of the first embodiment will be denoted by the same reference numerals as those used in the first embodiment, and detailed descriptions thereof will be 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 cut through a plane whose normal direction is the X-axis direction. It should be noted that 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 13As 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, and at an angle θ1 with the Z1 direction. Here, angle θ1 is an angle of 0 degrees to 30 degrees, preferably 5 degrees to 15 degrees, and more preferably 5 degrees to 10 degrees. Furthermore, the wall surface 601B is a reflective surface with a reflectivity of 70% or greater, preferably 85% or greater, and more preferably 90% or greater.

[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, and at an angle θ2 with the Z1 direction. Here, angle θ2 is an angle of 0 degrees to 30 degrees, preferably 5 degrees to 15 degrees, and more preferably 5 degrees to 10 degrees. Furthermore, the wall surface 602B is a reflective surface with a reflectivity of 70% or greater, preferably 85% or greater, and more preferably 90% or greater.

[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 14As shown, the illumination simulation of the second embodiment assumes the following: As in 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". Furthermore, as in 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". Furthermore, as in 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". Furthermore, as in the first embodiment, the illumination simulation of the second embodiment assumes a total amount of 83 W of ultraviolet light emitted for one second from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6. In the illumination simulation of the second 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”, similarly to the first embodiment.

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

[0157] It should be noted that, as described above, when the ultraviolet irradiation unit 5B is observed in cross section 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, distance dY1 is greater than distance dY2. Distance dY1 is the distance between the wall surface 601B and the liquid ejection unit 3 in the Y1 direction when the distance from the substrate 51 in the Z1 direction is distance dZ1 (an example of a "first distance"). Distance dY2 is the distance between the wall surface 601B and the liquid ejection unit 3 in the Y1 direction when the distance from the substrate 51 in the Z1 direction is distance dZ2 (an example of a "second distance") that is longer than distance dZ1. However, when angle θ1 is "θ1>0," distance dY1 is greater than distance dY2.

[0158] Figure 15 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as a “second illumination simulation”) involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface of interest, when the angle θ1 is set to “0 degrees” and the angle θ2 is set to “0 degrees”.

[0159] like Figure 15As shown, in the second illumination simulation, the maximum illumination on the recording paper PP is "6.3W / cm 2 ”, focusing on the range of the ultraviolet rays reaching the cut surface, which is the range of “-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 for 1 second is “75W”.

[0160] Figure 16 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as a “third illumination simulation”) involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "6.0 W / cm 2 ”, the range of ultraviolet rays reaching the cut surface is from “-1.08L” to “1.08L”. In addition, in the third illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is “76W”.

[0162] Figure 17 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as the "fourth illumination simulation") involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "5.7 W / cm 2 ”, the range of ultraviolet rays reaching the cut surface is from “-1.34 L” to “1.34 L”. In addition, in the fourth illumination simulation, the total illumination value of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is “77 W”.

[0164] Figure 18 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as the "fifth illumination simulation") involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "5.4 W / cm2 ”, the range of ultraviolet rays reaching the cut surface is from “-1.36 L” to “1.36 L”. In addition, in the fifth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is “77 W”.

[0166] Figure 19 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as the "sixth illumination simulation") involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "5.2 W / cm 2 ", the range of ultraviolet rays reaching the cut surface is from "-1.38L" to "1.38L". In addition, in the sixth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is "77W".

[0168] Figure 20 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as the "seventh illumination simulation") involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "5.2W / cm 2 ", the range of ultraviolet rays reaching the cut surface is from "-1.24L" to "1.24L". In addition, in the seventh illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is "76W".

[0170] Figure 21 It is shown in Figure 14 , a diagram showing the results of an illumination simulation (hereinafter referred to as "eight illumination simulations") involving the illumination of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B to the recording paper PP in the cut surface 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 on the recording paper PP is "5.1 W / cm 2”, the range of ultraviolet rays reaching the cut surface is from “-1.45L” to “1.45L”. In addition, in the eighth illuminance simulation, the total illuminance of ultraviolet rays irradiated from the ultraviolet irradiation unit 5B for 1 second is “76W”.

[0172] Figure 22 It shows Figures 15 to 21 The results of the second to eighth illumination simulations are shown in FIG. Figure 22 In FIG. 1 , the solid line FW represents the maximum illuminance WM in each illuminance simulation, and the dotted line FK represents the irradiation efficiency α in 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 for 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 for 1 second. Figure 22 In the equation, it is set as “θ1=θ2=θ”.

[0173] like Figure 22 As shown by the solid line FW, as the angle θ decreases, the maximum illuminance WM increases. Therefore, in order to more reliably cure the ink by 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 "0 degrees to 30 degrees," preferably "5 degrees to 15 degrees," and more preferably "5 degrees to 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 The inkjet printer according to the third embodiment will be described. It should be noted that, in the various embodiments exemplified below, elements having the same functions and effects as those in the first or second embodiment will retain the same reference numerals as those used in the description of the first or second embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0178] Figure 23This 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 cut through a plane whose normal direction is the X-axis direction. It should be noted that 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 23 As 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 includes 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 portion 62 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, the following situation is envisioned: similar to the first embodiment or the second embodiment, when the ultraviolet irradiation unit 5C is observed in a cross-section in the X-axis direction, the wall 601B extends in a direction between the Z1 direction and the Y1 direction, and in a 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 24As shown, the illumination simulation of the third embodiment assumes the following situation: similar to the first embodiment, the Y-axis position of the end of the cover plate 502 in the Y1 direction is set to "Y = L", the Y-axis position of the end of the cover plate 502 in the Y2 direction is set to "Y = -L", and the Y-axis width of the cover plate 502 is "2L = 25 mm". Furthermore, similar to the first embodiment, the illumination simulation of the third embodiment assumes a cell length HW of "8.1 mm" and a platen gap HP of "1.2 mm". Furthermore, similar to the first embodiment, the illumination simulation of the third embodiment assumes a case where the NY column is "4", the NX row is "16", the interval dLX is "4.4 mm", and the interval dLY is "4.6 mm". Furthermore, similar to the first embodiment, the illumination simulation of the third embodiment assumes a case where the total amount of ultraviolet light emitted from the 64 ultraviolet light sources E provided in the ultraviolet light source module 6 for one second is "83 W". In addition, in the illumination simulation of the third embodiment, the following situation is assumed: similar to the first and second embodiments, 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 24 , shows 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-sectional plane 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 on the recording paper PP is "5.9 W / cm 2 ", and the range of the ultraviolet rays reaching the cut surface 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 for 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 from the liquid ejection unit 3 than the center axis AX.

[0184] Figure 26 It is shown in Figure 24, shows 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 on the recording paper PP is "5.4W / cm 2 ", and the range of the ultraviolet rays reaching the cut surface 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 for 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 from the liquid ejection unit 3 than the center axis AX.

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

[0187] D. Modification

[0188] Each of the above methods can be modified in many ways. Specific modified methods are illustrated below. Two or more methods arbitrarily selected from the following examples can be appropriately combined within the scope of non-contradiction. It should be noted that in the modified examples illustrated below, for elements with the same effects and functions as those in the embodiments, 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, it can also be characterized in that, in the lens portion 82 of the ultraviolet light source E, the height dEZ of the lens portion 82 in the Z-axis direction is longer than the width dEY of the lens portion 82 in the Y-axis direction, and is longer than the 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 a light emitting portion 81, a lens portion 82, a sealing portion 83, and a connecting wiring portion 84, similarly to the ultraviolet light source E according to the embodiment. In Modification 1, the lens portion 82 includes a cylindrical base portion 821 and a hemispherical tip portion 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] When viewed from the base portion 821, the tip portion 822 is connected to the base portion 821 in the Z1 direction, 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, when viewed from the Z-axis direction, the tip portion 822 has a circular shape with a diameter dEY.

[0195] In this modification, lens portion 82 has a shape such that height dEZ1, height dEZ2, and width dEY satisfy the relationship "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. It should be noted that the ultraviolet light source in the comparative example has the same configuration as the ultraviolet light source E according to 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 shown by curve FS1. On the other hand, the ultraviolet light source in the comparative example has lower directivity, as shown by curve FS2. Therefore, by employing the ultraviolet light source E according to Modification 1 as the ultraviolet light source E for the ultraviolet irradiation unit 5 (or ultraviolet irradiation unit 5B or ultraviolet irradiation unit 5C), the irradiation efficiency of the ultraviolet rays 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 an embodiment in which a single ultraviolet irradiation unit 5 is provided in the inkjet printer 1 in the Y2 direction as viewed from the liquid ejection unit 3, the present invention is not limited to this embodiment. Alternatively, the inkjet printer 1 may include two ultraviolet irradiation units 5: one ultraviolet irradiation unit 5 provided in the Y2 direction as viewed from the liquid ejection unit 3, and one ultraviolet irradiation unit 5 provided in the Y1 direction as viewed from the liquid ejection unit 3. In this case, the inkjet printer 1 performs a printing process by discharging ink from the liquid ejection unit 3 onto the recording paper PP while the carriage 110 moves in the Y1 direction, and irradiating the recording paper PP with ultraviolet rays from the ultraviolet irradiation unit 5 provided in the Y2 direction as viewed from the liquid ejection unit 3. Furthermore, while the carriage 110 moves in the Y2 direction, ink is discharged from the liquid ejection unit 3 onto the recording paper PP, and ultraviolet rays are irradiated from the ultraviolet irradiation unit 5 provided in the Y1 direction as viewed from the liquid ejection unit 3.

[0200] D.3. Modification 3

[0201] In the first to third embodiments and modifications 1 and 2 described above, the inkjet printer 1 is assumed to include 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 not more than three, or may include five or more liquid ejection units 3.

[0202] E. Appendix

[0203] It should be noted that, in order to facilitate understanding of each embodiment, the reference numerals of the accompanying drawings are appended by parentheses for convenience, but this is not intended to limit the present invention to the embodiments shown in the drawings.

[0204] E.1. Appendix 1

[0205] Next, the inkjet printer 1 according to Appendix 1 will be described.

[0206] Appendix 1-1

[0207] The inkjet printer 1 involved in Appendix 1-1 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, wherein the ultraviolet irradiation unit 5 comprises a substrate 51, and an ultraviolet light source E emitting ultraviolet rays arranged on the substrate 51, and the substrate 51 has an aluminum base material 511.

[0208] According to Appendix 1-1, the ultraviolet irradiation unit 5 uses a substrate 51 having an aluminum base material 511. Therefore, compared to a method in which the ultraviolet irradiation unit uses a substrate having a copper base material, the ultraviolet irradiation unit 5 can be made lighter. Therefore, according to Appendix 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] Appendix 1-2

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

[0211] Appendix 1-3

[0212] The inkjet printer 1 involved in Appendix 1-3 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 1-1 or Appendix 1-2, wherein the surface area of ​​the substrate 51 is larger than the area of ​​the region where the ultraviolet light source E is set in the substrate 51.

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

[0214] Appendix 1-4

[0215] The inkjet printer 1 according to Appendix 1-4 is the inkjet printer 1 according to Appendix 1-1 to Appendix 1-3 , wherein an aluminum heat sink 52 is mounted on a base material 511 .

[0216] According to Appendix 1-4, the aluminum heat sink 52 is attached to the aluminum base 511. Therefore, compared to a method in which the aluminum heat sink 52 is attached to a copper base, the possibility of corrosion occurring at the boundary between the base 511 and the heat sink 52 can be reduced. Therefore, according to Appendix 1-4, there is no need to provide a heat sink between the base 511 and the heat sink 52, which can achieve miniaturization of the ultraviolet irradiation unit 5, reduce the number of parts of the ultraviolet irradiation unit 5, and increase the degree of freedom in the design of the ultraviolet irradiation unit 5.

[0217] Appendix 1-5

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

[0219] According to Appendix 1-5, a light-emitting diode is used as the ultraviolet light source E. Therefore, compared with the existing light sources such as high-pressure mercury lamps or xenon lamps, the ultraviolet light source E generates less heat and is smaller, making it suitable for being mounted on the slide 110.

[0220] Appendix 1-6

[0221] The inkjet printer 1 according to Appendix 1-6 is the inkjet printer 1 according to Appendix 1-1 to Appendix 1-5 , wherein a semiconductor temperature sensor 71 is provided on the substrate 51 .

[0222] According to Appendix 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 to stop the ultraviolet light source E or adjust the emission intensity of the ultraviolet light source E.

[0223] Appendix 1-7

[0224] The inkjet printer 1 involved in Appendix 1-7 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 1-1 to Appendix 1-6, wherein 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 Appendix 1-7, compared with a method in which the output from the temperature detection integrated circuit 7 is an analog signal, the possibility of noise being superimposed on the output signal from the temperature detection integrated circuit 7 can be reduced.

[0226] Appendix 1-8

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

[0228] E.2. Appendix 2

[0229] Next, the inkjet printer 1 according to Appendix 2 will be described.

[0230] Appendix 2-1

[0231] The inkjet printer 1 involved in Appendix 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, wherein the ultraviolet irradiation unit 5 comprises: a substrate 51; an ultraviolet light source E, which is arranged on the substrate 51, changes the radiation flux characteristics according to the temperature, and emits ultraviolet rays; an integrated circuit 7 for temperature detection as an integrated circuit, which 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 Appendix 2-1, the temperature detection integrated circuit 7 detects the temperature within the ultraviolet irradiation unit 5. Therefore, based on the detected 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. Furthermore, according to Appendix 2-1, the temperature detection integrated circuit 7 outputs the temperature detection signal DT as a digital signal. Therefore, compared to a method in which the output from the temperature detection integrated circuit 7 is an analog signal, the possibility of noise being superimposed on the temperature detection signal DT output by the temperature detection integrated circuit 7 can be reduced.

[0233] Appendix 2-2

[0234] The inkjet printer 1 involved in Appendix 2-2 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1, wherein 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 higher than temperature TE1.

[0235] Appendix 2-3

[0236] The inkjet printer 1 involved in Appendix 2-3 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 or Appendix 2-2, wherein the temperature detection integrated circuit 7 comprises: a semiconductor temperature sensor 71, which detects temperature and outputs an analog signal representing the detection result, i.e., a sensor output signal VT; 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 Appendix 2-3, the temperature detection integrated circuit 7 outputs the temperature detection signal DT as a digital signal. Therefore, compared with the method in which the output from the temperature detection integrated circuit 7 is an analog signal, the possibility of noise overlapping with the temperature detection signal DT output by the temperature detection integrated circuit 7 can be reduced.

[0238] Appendix 2-4

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

[0240] According to Appendix 2-4, since the emission of ultraviolet light from the ultraviolet light source E is controlled based on the temperature within the ultraviolet 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 method in which the intensity of the ultraviolet light is not adjusted. Furthermore, according to Appendix 2-4, the emission of ultraviolet light of inappropriate intensity from the ultraviolet light source E can be suppressed, thereby suppressing a decrease in print quality of the inkjet printer 1 that would otherwise result from irradiating the recording paper PP with ultraviolet light of inappropriate intensity.

[0241] Appendix 2-5

[0242] The inkjet printer 1 involved in Appendix 2-5 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-4, wherein the ultraviolet light source E has a light-emitting portion 81 that emits ultraviolet rays, and a lens portion 82 that seals the light-emitting portion 81, and the lens portion 82 is waterproofed.

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

[0244] Appendix 2-6

[0245] The inkjet printer 1 involved in Appendix 2-6 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-5, wherein the ultraviolet light source E has a light-emitting portion 81 that emits ultraviolet rays, and a lens portion 82 that seals the light-emitting portion 81, and the lens portion 82 is formed of silicone.

[0246] According to Appendix 2-6, silicone has water-repellent properties, and therefore, it is possible to suppress a decrease in the illuminance of the ultraviolet irradiation unit 5 caused by adhesion of ink to the lens portion 82 .

[0247] Appendix 2-7

[0248] The inkjet printer 1 involved in Appendix 2-7 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-5, wherein the ultraviolet light source E has 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 has a cover 502 that is arranged between the ultraviolet light source E and the recording paper PP and transmits ultraviolet rays.

[0249] According to Appendix 2-7, the cover plate 502 suppresses the adhesion of ink to the ultraviolet light source E. Therefore, it is possible to suppress the reduction in the illuminance of the ultraviolet irradiation unit 5 caused by the adhesion of ink to the lens portion 82 .

[0250] Appendix 2-8

[0251] The inkjet printer 1 involved in Appendix 2-8 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-7, wherein the ultraviolet irradiation unit 5 has a substrate 51, an ultraviolet light source E, and a frame 50 for accommodating an integrated circuit 7 for temperature detection.

[0252] Appendix 2-9

[0253] The inkjet printer 1 involved in Appendix 2-9 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-8, wherein a metal plating layer 54 is implemented on the wiring 514 for electrically connecting the ultraviolet light source E to the substrate 51.

[0254] According to Appendix 2-9, the metal plating 54 can reduce the resistance of the wiring 514 and stabilize the intensity of the ultraviolet light emitted by the ultraviolet light source E based on the stable power supply to the ultraviolet light source E.

[0255] Appendix 2-10

[0256] The inkjet printer 1 involved in Appendix 2-10 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 2-1 to Appendix 2-9, wherein the ultraviolet light source E has 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 Appendix 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 configuration in which the sealing portion 83 is formed of resin.

[0258] E.3. Appendix 3

[0259] Next, the inkjet printer 1 according to Appendix 3 will be described.

[0260] Appendix 3-1

[0261] The inkjet printer 1 involved in Appendix 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 in the Y1 direction on the recording paper PP; and a slide conveying motor 91, which is used to move the slide 110, wherein 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] It should be noted that, in Appendix 3, the wall surface 601B is an example of the “first wall surface”, the wall surface 602 is an example of the “second wall surface”, and the Y1 direction is an example of the “first direction”.

[0263] According to Appendix 3-1, the light absorptivity of wall surface 602 is higher than that of wall surface 601B. Therefore, compared to a configuration where the light absorptivity of wall surface 602 is lower than that of wall surface 601B, the intensity of ultraviolet light reaching liquid ejection unit 3 can be suppressed to a lower level. Therefore, according to Appendix 3-1, ink curing in liquid ejection unit 3 can be suppressed, and the occurrence of abnormal ink ejection in liquid ejection unit 3 can be reduced.

[0264] Appendix 3-2

[0265] The inkjet printer 1 according to Appendix 3-2 is the inkjet printer 1 according to Appendix 3-1, wherein the wall surface 601B is a mirror surface and the wall surface 602 is not a mirror surface.

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

[0267] Appendix 3-3

[0268] The inkjet printer 1 involved in Appendix 3-3 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 3-1 or Appendix 3-2, wherein the ultraviolet light source E has 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 greater than the diameter of the lens portion 82.

[0269] According to Appendix 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 Appendix 3-3, the illuminance of the ultraviolet light reaching the liquid ejection unit 3 can be suppressed to a low level.

[0270] Appendix 3-4

[0271] The inkjet printer 1 involved in Appendix 3-4 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 3-1 to Appendix 3-3, wherein the liquid ejection unit 3 ejects ink in the Z1 direction intersecting the Y1 direction, and the wall 601B is set in a manner such that the distance dY1 is longer than the distance dY2, the distance dY1 is the distance between the wall 601B in the Y1 direction and the liquid ejection unit 3 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 is the distance dY2 between the wall 601B in the Y1 direction and the liquid ejection unit 3 when the distance in the Z1 direction from the substrate 51 is the distance dZ2 longer than the distance dZ1.

[0272] It should be noted that, in Appendix 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 Appendix 3-4, the wall surface 601B is arranged to expand in the Y1 direction as it moves toward the Z1 direction. Therefore, compared with a configuration in which the wall surface 601B is not arranged to expand in the Y1 direction, the amount of ultraviolet rays irradiated from the ultraviolet irradiation unit 5C to the recording paper PP can be increased.

[0274] Appendix 3-5

[0275] The inkjet printer 1 according to Appendix 3-5 is characterized in that it is the inkjet printer 1 according to Appendix 3-1 to Appendix 3-4, wherein, when the ultraviolet irradiation unit 5C is viewed in a cross-section 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 greater than 0 degrees and less than 30 degrees. In other words, the inkjet printer 1 according to Appendix 3-5 is characterized in that it is the inkjet printer 1 according to Appendix 3-1 to Appendix 3-4, wherein the angle formed between the normal direction of the wall surface 601B and the Z1 direction is greater than 60 degrees and less than 90 degrees.

[0276] According to Appendix 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] Appendix 3-6

[0278] The inkjet printer 1 involved in Appendix 3-6 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 3-1 to Appendix 3-5, wherein the ultraviolet irradiation unit 5C has a cover 502 arranged between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0279] According to Appendix 3-6, the cover plate 502 suppresses adhesion of ink to the ultraviolet light source E, and thus a decrease in the illuminance of the ultraviolet irradiation unit 5C caused by adhesion of ink to the lens portion 82 can be suppressed.

[0280] Appendix 3-7

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

[0282] According to Appendix 3-7, when ink adheres to the cover 502 and the ink solidifies, it is not necessary to remove the ultraviolet irradiation unit 5C and only the cover 502 needs to be replaced. Therefore, compared with the method in which the cover 502 cannot be replaced, the maintainability of the ultraviolet irradiation unit 5C is improved.

[0283] E.4. Appendix 4

[0284] Next, the inkjet printer 1 according to Appendix 4 will be described.

[0285] Appendix 4-1

[0286] The inkjet printer 1 involved in Appendix 4-1 is characterized in that it comprises: 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 slide 110 for carrying the liquid ejection unit 3 and the ultraviolet irradiation unit 5B in a manner arranged in the Y1 direction and moving in the Y1 direction on the recording paper PP; and a slide conveying motor 91 for moving the slide 110, wherein the distance between the ultraviolet irradiation unit 5B and the recording paper PP is greater than 1 mm and less than 15 mm, the ultraviolet irradiation unit 5B comprises an ultraviolet light source E for emitting ultraviolet rays in a 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 observed in a cross-section from a direction perpendicular to the Y1 direction and the Z1 direction, the angle formed between the extension direction of the wall 601B and the Z1 direction is greater than 5 degrees and less than 15 degrees.

[0287] It should be noted that, in Appendix 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 Appendix 4-1, the angle formed between the extension direction of wall surface 601B and the Z1 direction is greater than 5 degrees and less than 15 degrees. Therefore, the efficiency of ultraviolet irradiation of recording paper PP by ultraviolet irradiation unit 5B can be improved compared to a case where the angle formed between the extension direction of wall surface 601B and the Z1 direction is less than 5 degrees. Furthermore, according to Appendix 4-1, the angle formed between the extension direction of wall surface 601B and the Z1 direction is greater than 5 degrees and less than 15 degrees. Therefore, the maximum intensity of ultraviolet irradiation of recording paper PP by ultraviolet irradiation unit 5B can be increased compared to a case where the angle formed between the extension direction of wall surface 601B and the Z1 direction is greater than 15 degrees. In other words, according to Appendix 4-1, it is possible to achieve both an increase in the maximum intensity of ultraviolet irradiation of recording paper PP by ultraviolet irradiation unit 5B and an increase in the efficiency of ultraviolet irradiation of recording paper PP by ultraviolet irradiation unit 5B.

[0289] Appendix 4-2

[0290] The inkjet printer 1 involved in Appendix 4-2 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 4-1, wherein, when the ultraviolet irradiation unit 5B is observed in a cross-section from 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 Appendix 4-2, it is possible to achieve both improvement in the maximum illuminance of ultraviolet rays on the recording paper PP by the ultraviolet irradiation unit 5B and improvement in the efficiency of ultraviolet rays irradiation on the recording paper PP by the ultraviolet irradiation unit 5B.

[0292] Appendix 4-3

[0293] The inkjet printer 1 involved in Appendix 4-3 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 4-1 or Appendix 4-2, wherein the ultraviolet light source E has 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 greater than the diameter of the lens portion 82.

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

[0295] Appendix 4-4

[0296] The inkjet printer 1 involved in Appendix 4-4 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 4-1 to Appendix 4-3, has rubber parts, and the wavelength of ultraviolet rays emitted from the ultraviolet light source E is greater than 250nm and less than 410nm.

[0297] Note that, in Appendix 4, rubber parts are an example of “specified parts”.

[0298] Appendix 4-4 reduces the possibility of ozone generation from ultraviolet light source E reacting with oxygen in the air compared to a method of irradiating ultraviolet light with a wavelength of 100 nm to 230 nm from ultraviolet light source E. Therefore, according to Appendix 4-4, degradation of rubber parts can be suppressed.

[0299] Appendix 4-5

[0300] The inkjet printer 1 involved in Appendix 4-5 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 4-1 to Appendix 4-4, wherein the ultraviolet irradiation unit 5B has a cover 502 arranged between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0301] According to Appendix 4-5, the cover plate 502 suppresses the adhesion of ink to the ultraviolet light source E. Therefore, it is possible to suppress the adhesion of ink to the ultraviolet light source E and the reduction in the illuminance of the ultraviolet irradiation unit 5B.

[0302] Appendix 4-6

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

[0304] According to Appendix 4-6, it is possible to replace only the cover 502 without removing the ultraviolet irradiation unit 5B. Therefore, compared with a method in which the cover 502 cannot be replaced, the maintainability of the ultraviolet irradiation unit 5B is improved.

[0305] E.5. Appendix 5

[0306] Next, the inkjet printer 1 according to Appendix 5 will be described.

[0307] Appendix 5-1

[0308] The inkjet printer 1 involved in Appendix 5-1 is characterized in that it comprises: a liquid ejection unit 3 for ejecting ink cured by ultraviolet irradiation onto the recording paper PP; an ultraviolet irradiation unit 5 for irradiating the ink ejected onto the recording paper PP with ultraviolet rays; a slide 110 for carrying the liquid ejection unit 3 and the ultraviolet irradiation unit 5 in a manner arranged in the Y1 direction and moving in the Y1 direction on the recording paper PP; and a slide conveying motor 91 for moving the slide 110, wherein the ultraviolet irradiation unit 5 comprises a plurality of ultraviolet light sources E for emitting ultraviolet rays in a Z1 direction intersecting the Y1 direction, one of the plurality of ultraviolet light sources E comprises a light-emitting portion 81 for emitting ultraviolet rays, and a lens portion 82 for sealing the light-emitting portion 81, the lens portion 82 comprises 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 width dEY which is the diameter of the base portion 821.

[0309] It should be noted that, in Appendix 5, an 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 Appendix 5-1, the directivity of 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 Appendix 5-1, the irradiation efficiency of 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 likelihood that 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 Appendix 5-2 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 5-1, wherein the plurality of ultraviolet light sources E are configured to be arranged in the Y1 direction and the 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] It should be noted that in Appendix 5, the X1 direction is an example of the “third direction”.

[0314] According to Appendix 5-2, the interval dLX is less than the interval dLY, thereby reducing unevenness in the illumination intensity of the ultraviolet light source E in the X1 direction. Therefore, according to Appendix 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 Appendix 5-3 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 5-1 or Appendix 5-2, wherein one ultraviolet light source E is adjacent to other ultraviolet light sources E among multiple ultraviolet light sources E in the X1 direction, and the irradiation range of ultraviolet rays emitted from one ultraviolet light source E on the recording paper PP overlaps with the irradiation range of ultraviolet rays emitted from other ultraviolet light sources E on the recording paper PP.

[0317] It should be noted that in Appendix 5, the other ultraviolet light source E is an example of a “second ultraviolet light source”.

[0318] According to Appendix 5-3, the irradiation range of ultraviolet rays on the recording paper PP by one ultraviolet light source E overlaps with that of the other ultraviolet light sources E, and thus unevenness in illumination of the ultraviolet light source E in the X1 direction can be reduced.

[0319] Appendix 5-4

[0320] The inkjet printer 1 involved in Appendix 5-4 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 5-1 to Appendix 5-3, has rubber parts, and the wavelength of ultraviolet rays emitted from the ultraviolet light source E is greater than 250nm and less than 410nm.

[0321] Note that, in Appendix 5, rubber parts are an example of “specified parts”.

[0322] Appendix 5-4 reduces the possibility of ozone generation from ultraviolet light source E reacting with oxygen in the air compared to a method of irradiating ultraviolet light with a wavelength of 100 nm to 230 nm from ultraviolet light source E. Therefore, according to Appendix 5-4, degradation of rubber parts can be suppressed.

[0323] Appendix 5-5

[0324] The inkjet printer 1 according to Appendix 5-5 is the inkjet printer 1 according to Appendix 5-1 to Appendix 5-4 , wherein the ultraviolet irradiation unit 5 includes a heat sink 52 for cooling the plurality of ultraviolet light sources E.

[0325] According to Appendix 5-5, the ultraviolet irradiation unit 5 includes the heat sink 52. Therefore, compared to a configuration in which the ultraviolet irradiation unit 5 does not include the heat sink 52, the service life of the plurality of ultraviolet light sources E can be extended. Therefore, according to Appendix 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] Appendix 5-6

[0327] The inkjet printer 1 involved in Appendix 5-6 is characterized in that the inkjet printer 1 is the inkjet printer 1 involved in Appendix 5-1 to Appendix 5-5, wherein the ultraviolet irradiation unit 5 has a cover 502 arranged between the ultraviolet light source E and the recording paper PP and transmitting ultraviolet rays.

[0328] According to Appendix 5-6, the cover plate 502 can suppress the adhesion of ink to the ultraviolet light source E, and thus the reduction in the illuminance of the ultraviolet irradiation unit 5 caused by the adhesion of ink to the ultraviolet light source E can be suppressed.

[0329] Appendix 5-7

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

[0331] According to Appendix 5-7, it is possible to replace only the cover 502 without removing the ultraviolet irradiation unit 5. Therefore, compared with a method in which the cover 502 cannot be replaced, the maintainability of the ultraviolet irradiation unit 5 is improved.

Claims

1. A liquid ejection device, characterized in that: have: A liquid ejecting unit ejects a liquid that is cured by ultraviolet irradiation onto a medium; an irradiation unit for irradiating the liquid sprayed onto the medium with ultraviolet rays; a carriage for carrying the liquid ejecting unit and the irradiation unit in a manner arranged in a first direction and moving in the first direction on the medium; as well as a motor for moving the carriage, The distance between the irradiation unit and the medium is greater than 1 mm and less than 15 mm. The irradiation unit comprises: an ultraviolet light source, emitting ultraviolet light in a second direction intersecting the first direction; and a reflecting surface that reflects at least a portion of the ultraviolet rays emitted from the ultraviolet light source, When the irradiation unit is viewed in section in a direction perpendicular to the first direction and the second direction, An angle formed between an extending direction of the reflecting surface and the second direction is greater than or equal to 5 degrees and less than or equal to 15 degrees.

2. The liquid ejection device according to claim 1, wherein When the irradiation unit is viewed in section in a direction perpendicular to the first direction and the second direction, An angle formed between an extending direction of the reflecting surface and the second direction is greater than or equal to 5 degrees and less than or equal to 10 degrees.

3. The liquid ejection device according to claim 1, wherein The ultraviolet light source includes a light emitting portion for emitting ultraviolet rays and a lens portion for sealing the light emitting portion. The height of the lens portion is greater than the diameter of the lens portion.

4. The liquid ejection device according to claim 1, wherein The liquid ejection device includes a specific rubber component. The wavelength of the ultraviolet rays emitted from the ultraviolet light source is 250 nm to 410 nm.

5. The liquid ejection device according to claim 1, wherein The irradiation unit includes a cover plate that is provided between the ultraviolet light source and the medium and transmits ultraviolet rays.

6. The liquid ejection device according to claim 5, wherein: The cover plate can be replaced without removing the ultraviolet light source from the irradiation unit.

7. An ultraviolet irradiation device, characterized in that: The ultraviolet irradiation device is arranged on the liquid ejection device, The liquid ejection device comprises: A liquid ejecting unit ejects a liquid that is cured by ultraviolet irradiation onto a medium; a carriage, carrying the liquid ejecting unit and moving in the first direction on the medium; as well as a motor for moving the carriage, The ultraviolet irradiation device is mounted on the carriage in a manner aligned with the liquid ejection unit in the first direction, and irradiates the liquid ejected onto the medium with ultraviolet rays. The distance between the ultraviolet irradiation device and the medium is greater than 1 mm and less than 15 mm. The ultraviolet irradiation device comprises: an ultraviolet light source, emitting ultraviolet light in a second direction intersecting the first direction; and a reflecting surface that reflects at least a portion of the ultraviolet rays emitted from the ultraviolet light source, When the ultraviolet irradiation device is viewed in section in a direction perpendicular to the first direction and the second direction, An angle formed between an extending direction of the reflecting surface and the second direction is greater than or equal to 5 degrees and less than or equal to 15 degrees.

8. The ultraviolet irradiation device according to claim 7, characterized in that When the ultraviolet irradiation device is viewed in section in a direction perpendicular to the first direction and the second direction, An angle formed between an extending direction of the reflecting surface and the second direction is greater than or equal to 5 degrees and less than or equal to 10 degrees.

9. The ultraviolet irradiation device according to claim 7, characterized in that The ultraviolet light source includes a light emitting portion for emitting ultraviolet rays and a lens portion for sealing the light emitting portion. The height of the lens portion is greater than the diameter of the lens portion.

10. The ultraviolet irradiation device according to claim 7, characterized in that The liquid ejection device includes a specific rubber component. The wavelength of the ultraviolet rays emitted from the ultraviolet light source is 250 nm to 410 nm.

11. The ultraviolet irradiation device according to claim 7, characterized in that have: The cover plate is arranged between the ultraviolet light source and the medium and transmits ultraviolet rays.

12. The ultraviolet irradiation device according to claim 11, characterized in that The cover plate can be replaced without removing the ultraviolet light source from the ultraviolet irradiation device.

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