Patent Grant
10183482
The present disclosure relates to a light irradiation apparatus for irradiating light of a line shape with a plurality of light sources arranged in a line shape, and more particularly, to a light irradiation apparatus having a cooling mechanism which radiates heat generated from light sources.
Conventionally, a printing apparatus for printing using a ultraviolet (UV) ink which is cured by UV light irradiation is known. This printing apparatus ejects an ink from a nozzle of a head to a medium, and irradiates a UV light on a dot formed on the medium. By UV light irradiation, the dot is cured and settled on the medium, so good printing may be enabled for a medium which is less prone to absorb a liquid. This printing apparatus is disclosed in, for example, Patent Literature 1.
Patent Literature 1 discloses a printing apparatus including a conveyor unit for conveying a print medium, six heads arranged in a conveying direction to respectively eject color inks of cyan, magenta, yellow, black, orange, and green, six pre-curing irradiation units placed at a downstream side in the conveying direction between each head for pre-curing (peening) a dot ink ejected on the print medium from each head, and a curing irradiation unit for curing the dot ink to settle the dot ink on the print medium. The printing apparatus disclosed in Patent Literature 1 performs two-steps curing of pre-curing and curing, on the dot ink to prevent a blurred color ink or dot expansion.
The pre-curing irradiation unit disclosed in Patent Literature 1 is placed above the print medium and irradiates a UV light on the print medium, hence it is a so-called UV light irradiation device, and irradiates a UV light of a line shape in a widthwise direction of the print medium. In response to a request for a lightweight and compact design of the printing apparatus itself, the pre-curing irradiation unit uses a light emitting diode (LED) as a light source, and a plurality of LEDs is arranged side by side along the widthwise direction of the print medium.
As described above, in the case where an LED is used as a light source, there is a degradation problem of light emitting efficiency and life caused by heat generated from the LED itself in that most of the power supplied is converted to heat. Also, like the pre-curing irradiation unit, in the case of an apparatus having a plurality of LEDs mounted therein, this problem is more serious in terms of the increased number of LEDs acting as a heat source. By this reason, a light irradiation apparatus using an LED as a light source is generally configured to inhibit the heat generation of the LED using a cooling structure such as a heat sink (for example, Patent Literature 2).
The light irradiation apparatus (light source apparatus) disclosed in Patent Literature 2 includes a plurality of LEDs, radiators thermally coupled to the LEDs respectively, and a fan that sends a cooling airflow along an arrangement direction of the radiators, and efficiently cools the radiators (i.e., the LEDs) by the airflow generated by the fan.
(Patent Literature 1) Japanese Patent Unexamined Publication No. 2013-252720
(Patent Literature 2) Japanese Patent Unexamined Publication No. 2011-154855
However, because the light irradiation apparatus of Patent Literature 2 is designed to flow air cooling the radiators in only one direction along the arrangement direction of the radiators (that is, along the arrangement direction of the light emitting diodes (LEDs)), air increases in temperature each time the air passes through the radiators, and as a consequence, a temperature difference occurs between the radiators (that is, the LEDs) arranged at an upstream side of the airflow and the radiators (that is, the LEDs) arranged at a downstream side. Generally, because the irradiation intensity of the LEDs has temperature-dependent characteristics, when a temperature difference occurs between the LEDs arranged in a line shape, non-uniformity of irradiation intensity occurs due to the temperature difference.
In this circumstance, the present disclosure aims to provide a light irradiation apparatus for emitting light of a line shape with a small temperature difference between LEDs and approximately uniform irradiation intensity.
To achieve the object, a light irradiation apparatus of the present disclosure is a light irradiation apparatus that irradiates, on an irradiation surface, light of a line shape extending in a first direction and having a predetermined line width in a second direction perpendicular to the first direction, and the light irradiation apparatus includes a substrate, a plurality of light sources placed on a surface of the substrate side by side at a predetermined interval along the first direction, with a direction of an optic axis being a third direction perpendicular to the first direction and the second direction, a plurality of heat radiation fins standing erect on an opposite surface of the substrate and arranged in rows in the first direction, and N cooling mechanisms placed side by side along the first direction to cover a plurality of heat radiation fins, in which N is an integer greater than or equal to 2, and each of the cooling mechanisms includes a case to receive a portion of the plurality of heat radiation fins and form a wind tunnel surrounding the portion of the plurality of heat radiation fins, and a cooling fan to bring air from outside, introduce the air to the wind tunnel, and generate an airflow in the first direction within the wind tunnel.
According to this construction, because the plurality of heat radiation fins is cooled approximately simultaneously, the plurality of heat radiation fins may be cooled uniformly and efficiently. Thus, the plurality of light sources placed on the substrate is also uniformly cooled, a temperature difference between each light source is significantly reduced, and a ultraviolet (UV) light of a line shape is emitted from the light irradiation apparatus with approximately uniform irradiation intensity.
Also, the case may include an intake opening for bringing the air from outside, and an exhaust opening for exhausting the air having passed through the wind tunnel, and the cooling fan may preferably be provided in at least one of the intake opening and the exhaust opening.
Also, the case may preferably be configured to have a space between the intake opening and the wind tunnel to cause the air from outside to be in a constant flow. According to this construction, air may be supplied to each heat radiation fin approximately uniformly.
Also, the case may preferably have dividers to divide the space and the wind tunnel.
Also, the intake opening and the exhaust opening of each of the cooling mechanisms may preferably be open to the third direction.
Also, the N may preferably be 2, and the exhaust opening of each of the cooling mechanisms may preferably be placed closer to the substrate than the intake opening, and is open to the first direction. Also, in this case, the intake opening of each of the cooling mechanisms may be configured to be open to the first direction. Also, the intake opening of each of the cooling mechanisms may be configured to be open to the third direction.
Also, the light source may be composed of at least one LED device.
Also, the light may preferably be light including a wavelength applicable to an ultraviolet curable resin.
As described above, according to the present disclosure, a light irradiation apparatus is implemented, which may emit light of a line shape with a small temperature difference between light emitting diodes (LEDs) and approximately uniform irradiation intensity.
Hereinafter, the embodiments of the present disclosure will be described in detail with reference to accompanying drawings. In the drawings, like or equivalent parts are given like reference numerals, and its description is not repeated.
As shown in
As shown in
As shown in
The substrate 201 is a wiring substrate of a rectangular shape formed from a material having high thermal conductivity (for example, aluminum nitride), and on its surface, 40 (X-axis direction)×2 (Y-axis direction) LED devices 203 are mounted in a square lattice shape along the X-axis direction and the Y-axis direction (
The LED device 203 has a LED chip (not shown) having a light emitting surface of an approximately square shape, and is a semiconductor device that emits a UV light of 365 nm wavelength when supplied with the drive current from the LED driver circuit. When the drive current is supplied to each LED device 203, a UV light is emitted from each LED device 203 in a light amount based on the drive current, and a UV light of a line shape approximately parallel in the X-axis direction is emitted from the light irradiation apparatus 1. Also, for each LED device 203 of this embodiment, the drive current being supplied to each LED device 203 is adjusted to emit a UV light in an approximately uniform light amount, and the UV light of a line shape emitted from the light irradiation apparatus 1 has an approximately uniform light amount distribution in the X-axis direction and the Y-axis direction.
The heat sink 210 is a member that is placed in close contact with an opposite surface (a surface on an opposite side to a surface where the LED devices 203 are mounted) of the substrate 201, and radiates heat generated from each LED device 203, and is integrally formed from a material having good thermal conductivity such as aluminum or copper (
The base plate 211 is a member of a rectangular plate shape, and its lower surface (a surface facing the opposite surface of the substrate 201) is closely adhered to the opposite surface of the substrate 201, for example, with a heat radiating grease or an adhesive having high thermal conductivity. Thus, the heat generated from the LED devices 203 is quickly conducted to the base plate 211.
Also, as shown in
As shown in
The pair of arms 312 and 314 are a metal member (for example, aluminum) of a rectangular rod shape extending along the Z-axis direction, and the light irradiation unit 200 and the wind tunnel case 310 are fixed between the arms 312 and 314 (
The wind tunnel case 310 is a metal member (for example, aluminum) covering the heat radiation fins 213, and as shown in
The first side panel 310a and the second side panel 310b are a member of an approximately rectangular plate shape provided to clamp the heat radiation fins 213 from both sides of the Y-axis direction, and are respectively connected to the pair of arms 312 and 314 and fastened by bolt tightening or the like. Also, the proximal end of the first side panel 310a and the second side panel 310b (an end on the positive side of the Z-axis direction) comes into contact with the upper surface of the base plate 211 (that is, the surface where the heat radiation fins 213 stand erect) and the distal end (an end on the negative side of the Z-axis direction) is connected to the rear panels 310d and 310e and fastened by bolt tightening or the like.
The partition 310c is a plate-shaped member that is vertically placed between the first side panel 310a and the second side panel 310b and divides a space within the wind tunnel case 310 into two spaces R1 and R2 along the X-axis direction. As shown in
The rear panels 310d and 310e are a plate-shaped member vertically placed between the first side panel 310a and the second side panel 310b. The rear panel 310d is bent in the shape of ‘<’ when viewed in the Y-axis direction, and includes a first linear part 310d1 extending parallel in the X-axis direction and a second linear part 310d2 inclined relative to the X-axis direction. One end of the rear panel 310d (a proximal end of the first linear part 310d1) is connected to the arm 312, and the other end (a distal end of the second linear part 310d2) is connected to the partition 310c and the rear panel 310e. Similar to the rear panel 310d, the rear panel 310e is bent in the shape of ‘<’ when viewed in the Y-axis direction, and includes a first linear part 310e1 extending parallel in the X-axis direction and a second linear part 310e2 inclined relative to the X-axis direction. One end of the rear panel 310e (a proximal end of the first linear part 310e1) is connected to the arm 314, and the other end (a distal end of the second linear part 310e2) is connected to the partition 310c and the rear panel 310d.
The first divider 310f is a plate-shaped member that is vertically placed between the first side panel 310a and the second side panel 310b and divides the space R1 into two spaces R1U and R1L in the Z-axis direction. As shown in
The second divider 310g is a plate-shaped member that is vertically placed between the first side panel 310a and the second side panel 310b and divides the space R2 into two spaces R2U and R2L in the Z-axis direction. As shown in
The arm 312 of this embodiment has an approximately circular opening 312a (intake) formed at a location corresponding to the space R1U, and an approximately circular opening 312b (exhaust) formed at a location corresponding to the space R1L. Also, the intake fan 301 is attached to the outside of the opening 312a, and the exhaust fan 305 is attached to the outside of the opening 312b. Thus, when the intake fan 301 and the exhaust fan 305 rotate, air from outside is brought into the space R1 along the X-axis direction to generate a cooling airflow as indicated by an arrow in
Similar to the arm 312, the arm 314 of this embodiment has an approximately circular opening 314a (intake) formed at a location corresponding to the space R2U, and an approximately circular opening 314b (exhaust) formed at a location corresponding to the space R2L. Also, the intake fan 303 is attached to the outside of the opening 314a, and the exhaust fan 307 is attached to the outside of the opening 314b. Thus, when the intake fan 303 and the exhaust fan 307 rotate, air from outside is brought into the space R2 along the X-axis direction to generate a cooling airflow as indicated by an arrow in
As described above, the cooling apparatus 300 of this embodiment cools the heat radiation fins 213 respectively placed in the spaces R1L and R2L approximately simultaneously by dividing the space within the wind tunnel case 310 into the two spaces R1 and R2 along the X-axis direction, and generating a cooling airflow in each of the spaces R1 and R2 (that is, by two cooling mechanisms). By this reason, the cooling apparatus 300 of this embodiment has a cooling capacity about twice larger than that of a cooling structure of cooling in an airflow flowing in only one direction within one space according to a prior art, and enables uniform and efficient cooling of the heat radiation fins 213. Accordingly, the plurality of LED devices 203 placed on the substrate 201 is uniformly cooled, a temperature difference between each LED device 203 is significantly reduced, and a UV light of a line shape is emitted from the light irradiation apparatus 1 with approximately uniform irradiation intensity.
As shown in
While this embodiment has been described hereinabove, the present disclosure is not limited to the above construction and a variety of changes and modifications may be made within the technical aspect and scope of the invention.
For example, although it is described that 40 (X-axis direction)×2 (Y-axis direction) LED devices 203 are mounted on the substrate 201 in the light irradiation unit 200 of this embodiment, the number of LED devices 203 arranged in the X-axis direction and the Y-axis direction may be suitably increased or decreased based on the required specification. Also, each LED device 203 may be configured to have a plurality of LED chips (dies) inside.
Also, although it is described that the LED devices 203 of this embodiment emits a UV light of 365 nm wavelength, they may be those that emit a UV light of another wavelength and visible light or infrared light, and the purpose of use of the light irradiation apparatus 1 is not limited to a printing apparatus for printing using a UV ink.
Also, although the cooling apparatus 300 of this embodiment is configured to have the intake fan 301 and the exhaust fan 305 for the space R1 and the intake fan 303 and the exhaust fan 307 for the space R2, as long as a predetermined cooling airflow is generated in the spaces R1 and R2, at least one of the intake fan and the exhaust fan may be provided for each of the spaces R1 and R2.
Also, although this embodiment describes that the outer case 100 and the wind tunnel case 310 are separately formed, the two cases may be integrally formed.
In this embodiment, air from outside is brought into the space R1U (or R2U) by the intake fan 301 (or 303), and is in a constant flow within the space R1U (or R2U). Also, the air in the space R1U (or R2U) is sent to the space R1L (or R2L), passes in between the heat radiation fins 213 placed in the space R1L (or R2L), and is exhausted to the outside by the exhaust fan 305 (or 307). Thus, according to the construction of this embodiment, because the heat radiation fins 213 respectively placed in the spaces R1L and R2L are cooled approximately simultaneously, uniformly, and efficiently, the plurality of LED devices 203 placed on the substrate 201 are also uniformly cooled, a temperature difference between each LED device 203 is small, and a UV light of a line shape is emitted from the light irradiation apparatus 1A with approximately uniform irradiation intensity.
As shown in
Also, the cooling device 300B of the light irradiation apparatus 1B according to this embodiment has dividers 310fB, 310gB, 310hB, and 310iB to divide the spaces R1, R2, R3, and R4 into two spaces in the X-axis direction. In this way, as the spaces R1, R2, R3, and R4 are divided by the dividers 310fB, 310gB, 310hB, and 310iB, air brought into the spaces R1, R2, R3, and R4 flows toward the heat radiation fins 213 placed below the spaces R1, R2, R3, and R4 (in the positive direction on the Z-axis), and the heat radiation fins 213 are thus reliably cooled.
As described above, because the heat radiation fins 213 respectively placed in the spaces R1, R2, R3, and R4 are cooled approximately simultaneously, uniformly and efficiently by the construction of this embodiment, the plurality of LED devices 203 placed on the substrate 201 is also uniformly cooled, a temperature difference between each LED device 203 is small, and a UV light of a line shape is emitted from the light irradiation apparatus 1B with approximately uniform irradiation intensity. Also, because this embodiment is configured to cool each of the spaces R1, R2, R3, and R4 (that is, configured to have four cooling mechanisms), the construction of this embodiment has a higher cooling capacity and may cool the heat radiation fins 213 more uniformly as compared to the first and second embodiments configured to cool each of the spaces R1 and R2 (that is, configured to have two cooling mechanisms). Also, although the cooling apparatus 300B of this embodiment is configured to cool the space in the wind tunnel case 310B divided into four spaces R1, R2, R3, and R4, the construction is not limited thereto, and the number of divisions is suitably set based on the required specification (that is, the degree of uniformity of UV light irradiation intensity).
It should be understood that the disclosed embodiments are meant to be exemplary and illustrative in all aspect, not limiting in scope. The scope of the invention is defined by the appended claims, not in the foregoing description, and all changes and modifications are intended to be included in the meaning and scope equivalent to the claims.
1, 1A, 1B: Light irradiation apparatus, 100: Outer case, 101: Front panel, 101a: Light emitting window, 103: Left side panel, 105: Right side panel, 200: Light irradiation unit, 201: Substrate, 203: LED device, 210: Heat sink, 211: Base plate, 213: Heat radiation fin, 300, 300A, 300B: Cooling apparatus, 301, 303, 301B, 302B, 303B, 304B: Intake fan, 305, 307, 305B, 306B, 307B, 308B: Exhaust fan, 310: Wind tunnel case, 310a: First side panel, 310b: Second side panel, 310c: Partition, 310d, 310e, 310dB: Rear panel, 310f: First divider, 310g: Second divider, 310fB, 310gB, 310hB, 310iB: Divider, 312, 314: Arm, 312a, 312b, 314a, 314b, 310da, 310ea: Opening
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-147246 | Jul 2014 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20080257186 | Kusaka | Oct 2008 | A1 |
| 20120133716 | Aizawa | May 2012 | A1 |
| 20130182436 | Payne et al. | Jul 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 2011-154855 | Aug 2011 | JP |
| 2012-182063 | Sep 2012 | JP |
| 2012-182068 | Sep 2012 | JP |
| 2013-252720 | Dec 2013 | JP |
| 2011-13164 | Apr 2011 | TW |
| 2013-46176 | Nov 2013 | TW |
| Number | Date | Country | |
|---|---|---|---|
| 20160016337 A1 | Jan 2016 | US |
