JP2012024708A - Ultraviolet irradiation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet irradiation apparatus which can effectively improve the illuminance of ultraviolet ray received by an irradiation object at low cost.SOLUTION: The ultraviolet irradiation apparatus includes: at least one light source unit that has two or more ultraviolet light sources 32 lining along a width direction of an irradiation part which is orthogonal to a conveyance direction of the irradiation object; and a pair of reflecting members 61 and 62 disposed between the light source unit and the irradiation object so as to sandwich each light source unit from the upstream side and the downstream side of the conveyance direction. Each of the reflecting members has the first reflection parts 611 and 621 opposed to the irradiation object.

Description

  The present invention relates to an ultraviolet irradiation device that irradiates an object with ultraviolet rays.

  Ultraviolet rays are widely used in manufacturing processes such as ink curing, semiconductor adhesion, and alignment film formation. It is necessary to efficiently irradiate the target with such ultraviolet rays. For example, Patent Document 1 discloses the following ultraviolet irradiation device. In this ultraviolet irradiation device, an arc-shaped reflector is disposed so as to surround the ultraviolet discharge lamp, and ultraviolet rays emitted from the lamp are irradiated toward the object.

JP 2008-86890 A

  By the way, in order to pass through the above-described steps effectively, it is necessary to make the illuminance of ultraviolet rays received by the object as high as possible. In order to increase the illuminance, there is a method of giving directivity to ultraviolet rays by increasing the output of the lamp and using a reflector surrounding the lamp as described above. However, as the demand for ultraviolet irradiation increases, a method for increasing the illuminance at the lowest possible cost has been demanded.

  The present invention has been made to solve the above problem, and an object thereof is to provide an ultraviolet irradiation device capable of effectively improving the illuminance of ultraviolet rays received by an object to be irradiated at low cost. .

  The present invention is an ultraviolet irradiation device for irradiating an object to be irradiated with ultraviolet rays, and includes at least one light source unit having a plurality of ultraviolet light sources arranged along an irradiation object width direction orthogonal to the conveyance direction of the object to be irradiated; A pair of reflecting members disposed between the light source unit and the object to be irradiated and sandwiching each light source unit from the upstream side and the downstream side in the transport direction, and each of the reflecting members Has a first reflecting portion facing the irradiated object.

  According to this configuration, since the first reflecting portion facing the object to be irradiated is provided on the reflecting member sandwiching the light source unit, the ultraviolet light reflected on the surface of the object to be irradiated out of the ultraviolet light irradiated to the object to be irradiated. Can be reflected by the first reflecting portion and irradiated again to the irradiated object. For this reason, it is possible to efficiently irradiate the irradiated object with ultraviolet rays emitted from the light source unit. That is, the illuminance of ultraviolet rays received by the irradiated object can be improved at low cost without increasing the output of the ultraviolet light source. For example, when irradiating ultraviolet rays to cure the ink on the substrate, in order to cure the ink, in addition to the peak illuminance above a predetermined level, an integrated amount that irradiates ultraviolet rays with a predetermined illuminance above a predetermined time is required. Become. In particular, in radical polymerization type ultraviolet curable ink, it is necessary to irradiate ultraviolet rays at a predetermined minimum illuminance or higher necessary for drying. Integrated illumination must be achieved. In the present invention, since the ultraviolet light reflected from the irradiated object can be used as described above, the illuminance can be increased as a whole, and the integrated amount can be increased in addition to the peak illuminance.

  In the said ultraviolet irradiation apparatus, a some light source unit can be arrange | positioned along a conveyance direction at predetermined intervals. And the reflective surface which follows a conveyance direction can be formed by the 1st reflection part of each reflection member arrange | positioned between adjacent light source units. When a plurality of light source units are arranged, the ultraviolet rays emitted from the respective light source units are overlapped with each other to increase the illuminance. Thereby, it is thought that the amount of reflection from the irradiated object also increases at this location. Therefore, by arranging the first reflecting portions of the reflecting members of the adjacent light source units so as to be continuous, the ultraviolet rays reflected from the irradiated object can be reflected without waste, and the illuminance of the irradiated object is further improved. Can do.

  In each reflecting member, a plurality of first reflecting portions can be provided at predetermined intervals along the irradiated object width direction. If two adjacent reflecting members between the respective light source units are arranged so that the first reflecting portions are engaged with each other, a reflecting surface continuous along the transport direction can be formed. If it does in this way, even if it is a case where the space | interval of adjacent light source units is narrow, a continuous reflective surface with a narrow width | variety can be formed combining two reflection members.

  Each reflecting member can be provided with a second reflecting portion that extends from the ultraviolet light source toward the substrate. Further, all or at least a part of the second reflecting portion has a weak ultraviolet ray whose incident angle from the ultraviolet light source to the substrate to be printed is equal to or larger than a predetermined reference angle and hardly contributes to curing inside the ink. It is desirable that the light is reflected so as to be smaller than the reference angle.

  According to this configuration, the following effects are obtained. The farther the irradiated ultraviolet rays are from the light source, the larger the incident angle to the printing material. When the ultraviolet rays exceed a predetermined reference angle, the amount of reflection increases. On the other hand, in this invention, the reflection member which has the 1st reflection part extended toward a to-be-printed material from the ultraviolet light source is provided. And this 1st reflection part makes the incident angle smaller than a reference angle, the incident angle from the ultraviolet light source to a to-be-printed object becomes more than a reference angle, and the light quantity which affects the hardening inside an ink becomes weak. It is configured to reflect. Accordingly, it is possible to prevent the printed material from being irradiated with weak ultraviolet rays that are difficult to contribute to the curing of the ink, and it is possible to improve the illuminance of the ultraviolet rays on the printed material. Thereby, the ink can be effectively cured. The "reference angle" here is a value resulting from the type of ink, etc., but as a result of the inventor's investigation, when entering the ink from the air, it is in the range of 30 to 60 degrees, In the case of general ink, it is often in the range of 40 to 50 degrees.

  The second reflecting portion can be in various modes. For example, each reflection member can be formed of a plate material, and the second reflection portion can be formed by being bent so as to be concave on the opposite reflection member side by at least one crease extending in the irradiation object width direction.

  Further, at least one of the second reflecting portions facing each other with the light source unit interposed therebetween is configured to approximately form a part of an ellipse in a cross section, and the light source unit is disposed in the vicinity of one focal point in the ellipse in the cross section. Can do.

  Thereby, the following effect can be acquired. In general, it is known that when a reflector is formed in an elliptical shape and a light source is arranged in the vicinity of the focal point on one end side of the major axis of the ellipse, the light is condensed on the focal point on the other end side of the major axis. However, as in the present invention, when the light source is not a point light source but an ultraviolet light source having a certain size, the light source has a certain width in the vicinity of the focal point, rather than focusing on one point of the focal point. Ultraviolet rays that approximate the parallel light are irradiated. On the other hand, when the plate material is bent and an approximate ellipse is formed by the second reflecting portion, the reflected ultraviolet rays do not exhibit the behavior described above, and the ultraviolet rays are kept in the transport direction while maintaining the incident angle. Can be dispersed. That is, since the ultraviolet rays irradiated to the printing material are more generally dispersed than the parallel light, the irradiation width of the ultraviolet rays received by the printing material can be increased. Further, since the reflecting member can be formed by bending the plate material, the manufacturing becomes easy. The “near focus” mentioned above means the focus or its vicinity. The range of “near” is as follows. First, it is known that if the light source unit is at the focal point, the light is condensed at another focal point, and the irradiation range becomes larger as the light source unit moves away from the focal point. Accordingly, “near” means a range from a required irradiation range to the printing material to a position where the light collection range becomes large.

  According to the ultraviolet irradiation device according to the present invention, it is possible to effectively improve the illuminance of ultraviolet rays received by the irradiated object at low cost.

1 is a schematic side view showing an embodiment of a printing machine equipped with an ultraviolet irradiation device according to the present invention. It is a top view of FIG. It is a perspective view showing one embodiment of an ultraviolet irradiation device concerning the present invention. FIG. 4 is a bottom view of FIG. 3. FIG. 4 is a plan view of FIG. 3. It is the perspective view which permeate | transmitted a part of FIG. It is the sectional view on the AA line of FIG. It is a perspective view which shows schematic structure of an ultraviolet irradiation part. It is an expanded sectional view showing a schematic structure of an ultraviolet irradiation part. It is a perspective view which shows the assembly of a 2nd reflection member. It is the BB sectional view taken on the line of FIG. It is an expanded sectional view showing an example of ultraviolet irradiation in an ultraviolet irradiation part. It is an expanded sectional view showing an example of ultraviolet irradiation in an ultraviolet irradiation part. It is a figure which shows the example of the illumination intensity of the ultraviolet-ray which a to-be-printed material receives. It is an expanded sectional view showing an example of ultraviolet irradiation in an ultraviolet irradiation part. It is a figure which shows shapes, such as a reflection member used for an Example and a comparative example. It is a figure which shows the aspect of a comparative example, and evaluation of illuminance. It is a figure which shows the aspect of the Example of this invention, and evaluation of illumination intensity.

  Hereinafter, an embodiment in which the ultraviolet irradiation device according to the present invention is applied to a printing press will be described with reference to the drawings. FIG. 1 is a schematic side view of a printing machine equipped with the ultraviolet irradiation device, and FIG. 2 is a plan view of FIG.

  First, a printing machine equipped with the ultraviolet irradiation device of the present embodiment will be described. This printing machine applies black (K), cyan (C), magenta (M), yellow (Y), and transparent finishing ink (OP) in this order to the sheet P to be printed P. In this way, a full color image is formed. The ink used here has ultraviolet curable properties and contains a radical polymerization type or chaotic polymerization type ultraviolet curable resin. As shown in FIGS. 1 and 2, the printing machine is provided with printing units 1K, 1C, 1M, 1Y, and 1P for applying the above-described five inks from the right side to the left side of the drawing. Yes. Each printing unit 1 includes an ink supply device 11 that supplies ink. Below each ink supply device 11, a plate cylinder 12, a rubber cylinder 13, and an impression cylinder 14 to which the ink is transferred face downward. Arranged in this order. Further, an ultraviolet irradiation device 2 that irradiates the printing material P with ultraviolet rays is disposed on the downstream side in the circumferential direction from the position in contact with the rubber cylinder 13 in each impression cylinder 14.

  Between each printing unit 1, the transfer cylinder 15 for delivering the to-be-printed material P is arrange | positioned. More specifically, a transfer cylinder 15 is arranged between the impression cylinders 14 at the lowermost part of each printing unit 1, and the printing material P to which ink is applied between each rubber cylinder 13 and the impression cylinder 14. Is conveyed by the transfer cylinder 15 to the impression cylinder 14 of the downstream printing unit. It should be noted that the order in which the inks are arranged may be other than those described above.

  Next, an ultraviolet irradiation device will be described with reference to FIGS. 3 is a perspective view of the ultraviolet irradiation device, FIG. 4 is a bottom view of FIG. 3, and FIG. 5 is a plan view of FIG.

  As shown in FIGS. 3 and 4, the ultraviolet irradiation device 2 has a box-shaped casing 21 extending in a long shape, and ultraviolet rays are irradiated from the bottom surface of the casing 21. In the following, the direction in which the casing 21 extends is referred to as the longitudinal direction, the direction orthogonal thereto is referred to as the width direction, the right side in FIG. 3 in the longitudinal direction is referred to as the first end portion, and the left side is referred to as the second end portion. However, in the description with respect to the substrate P, the width direction may be referred to as “conveying direction” and the longitudinal direction may be referred to as “printing width direction (irradiation object width direction)”. A plurality of ultraviolet light emitting diodes (ultraviolet LEDs) that irradiate ultraviolet rays, a control board that controls driving of the ultraviolet LEDs, and the like are disposed inside the housing 21. The length of the casing 21 in the longitudinal direction corresponds to the width of the printing material P, and can be irradiated with ultraviolet rays over the entire printing width of the printing material P. The casing 21 is formed in a pentagonal cross section having a top on the upper side. As shown in FIG. 5, the casing 21 is carried on both ends of one upper surface (upper side in FIG. 5). A handle 22 is attached.

  As shown in FIG. 5, a water cooling water supply hole 23 and a discharge hole 24 to be described later are provided at the first end of the housing 21, and are connected to a DC inverter chiller (not shown). In addition, a power terminal 25 and a signal terminal 26 that receives and transmits control signals from the printing press are provided in the vicinity of the supply hole 23 and the discharge hole 24. In addition, a plurality of slits extending in parallel with the longitudinal direction are formed on the first end side on the upper surface of the housing 21 provided with the handle 22, and these slits constitute an air inlet 27. Yes. On the other hand, as shown in FIG. 3, an exhaust port 28 for discharging the air in the housing 21 is formed on the end surface of the second end portion.

  Next, the internal structure of the housing will be described with reference to FIGS. 6 is a partially transparent perspective view of FIG. 3, and FIG. 7 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 7, the inside of the housing 21 is divided into three regions from the bottom to the top, and in each region, the ultraviolet irradiation unit 3, the cooling unit 4, and the control unit 5 are arranged from the bottom. Is arranged.

  First, the ultraviolet irradiation unit 3 will be described. The ultraviolet irradiation unit 3 includes a support substrate 31 that abuts a lower surface 413 of a cooling block 41 of the cooling unit 4 to be described later. ) 32 is implemented. The plurality of ultraviolet LEDs 32 are arranged in four rows extending in the longitudinal direction, and are configured by two LED units 33 each having two rows. Both LED units 33 are arranged at a predetermined interval in the width direction, and a spacer 34 extending downward is arranged between the units 33. In addition, support blocks 35 are arranged at the end portions in the width direction of the ultraviolet irradiation unit 3, and the support blocks 35 and the spacers 34 are arranged at predetermined intervals, so that each LED unit 33 has a predetermined interval. An irradiation space S is formed below each. That is, on both sides of the spacer 34, an irradiation space S through which the ultraviolet light irradiated from each LED unit 33 passes is formed. Each support block 35 is fixed to the side surface of the cooling block 41 by a connecting portion 35a extending upward.

  And in the irradiation space S under each LED unit 33, the reflector which reflects so that the irradiated ultraviolet rays may go below is arrange | positioned. The reflector of the present embodiment reflects the ultraviolet light diffusing from the ultraviolet LED 32 so as to face downward, and is formed of four parts. That is, a pair of first reflecting members 61 fixed to each support block 35 and a pair of second reflecting members 62 fixed to the spacer 34 are configured. Then, by arranging the first and second reflecting members 61 and 62 so as to sandwich the ultraviolet rays irradiated from the LED unit 33 in the width direction, the ultraviolet rays are reflected downward. Each reflecting member can be formed, for example, by coating a reflecting agent on the surface of a plate material such as aluminum. As such a reflector, for example, MIRO (trademark) manufactured by alanod can be used, but is not particularly limited.

  Here, the reflecting members 61 and 62 will be described in more detail with reference to FIGS. FIG. 8 is a perspective view of the schematic structure of the ultraviolet irradiation unit as viewed from below, FIG. 9 is an enlarged cross-sectional view of the ultraviolet irradiation unit, and FIG. 10 is a perspective view showing the assembly of the second reflecting member. In FIG. 8, the spacer 34 and the support block 35 are omitted for convenience. As shown in FIGS. 7 to 10, each first reflecting member 61 is formed of a plate material having a substantially L-shaped cross section, and includes a first reflecting portion 611 extending along the lower surface of the support block 35, and a first reflecting member. The second reflection part 612 extends upward from the end of the part 611 along the support block 35 in the irradiation space S. On the other hand, each of the second reflecting members 62 is also formed of a plate material having a substantially L-shaped cross section. The first reflecting portion 621 extends along the lower surface of the spacer 34 and the support block 35 extends from the end of the first reflecting portion 621. And a second reflecting portion 622 extending upward in the irradiation space S.

  As described above, in each irradiation space S, the first reflecting member 61 and the second reflecting member 62 are arranged so as to sandwich the irradiated ultraviolet rays, but the second reflecting portion 612 of each reflecting member 61, 62 is disposed. , 622 are bent in an arc shape surrounding the irradiation space S by two folds H extending in the transport direction. Accordingly, the second reflecting portions 612 and 622 of the reflecting members 61 and 62 facing each other approximately constitute a part of an ellipse E as shown in FIG. Therefore, it is possible to reflect ultraviolet rays downward with simple processing without forming a complete ellipse. Further, each second reflecting member 62 is not provided with the second reflecting portion 622 over the entire length in the longitudinal direction, but is provided with a predetermined interval as shown in FIG. Accordingly, the two opposing second reflecting members 62 are arranged such that the first reflecting portions 621 alternately engage with each other, and thereby the first reflecting portions 621 continuously extend along the lower surface of the spacer 34. Become. By the way, when forming such a shape, it is also conceivable to form the two second reflecting members 62 with a single plate material. In other words, the first reflecting portion can be formed between the LED units 33 by bending the plate material at at least two places. However, when the interval between the LED units 33 is narrow and the width of the first reflecting portion must be reduced, it may be difficult to bend at two locations. In such a case, as shown in FIG. 10, if the second reflecting member 62 is formed, the first reflecting portion 621 can be formed by bending at one place, which is effective. In addition, since only a part can be replaced when damaged, the maintenance cost can be reduced as compared with the case of integrating them.

  Moreover, the 2nd reflection parts 612 and 622 of each reflection member 61 and 62 are formed as follows. As shown in FIG. 9, each of the second reflecting portions 612 and 622 has two fold lines H extending in the transport direction G, thereby forming a part of an approximate ellipse E. In particular, among the LED units 33 composed of two rows of ultraviolet LEDs 32, the adjacent ultraviolet LEDs 32 are arranged in the vicinity of the focal point of the ellipse E. The distance between the ultraviolet irradiation device 2 and the printing material P is determined so that the printing material P passes through the vicinity of the focal point N below the ellipse E.

  Next, the dirt prevention plate 37 will be described. As shown in FIG. 7, a dirt prevention plate 37 that covers both irradiation spaces S is provided at the bottom of the ultraviolet irradiation unit 3, that is, the bottom surface of the housing 21. The dirt prevention plate 37 is a transparent material that can transmit ultraviolet rays, and is formed of quartz glass or the like.

  Next, the cooling unit 4 will be described with reference to FIG. 11 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 7, the cooling unit 4 has a flat cooling block 41 formed of a material having high thermal conductivity such as aluminum. As described above, the support substrate 31 of the ultraviolet LED 32 is attached to the lower surface of the cooling block 41. However, in order to increase thermal conductivity, a known heat dissipation is provided between the lower surface of the cooling block 41 and the support substrate 31. Grease is applied. Thereby, the unevenness | corrugation of the contact part of the cooling block 41 and the support substrate 31 can be filled, and the heat conductive effect is improved. On the other hand, a U-shaped groove 412 to which water for water cooling is supplied is formed on the upper surface 411 of the cooling block 41. More specifically, as shown in FIGS. 7 and 11, the groove 412 is formed in a U shape in a plan view in which a first passage 412 a and a second passage 412 b extending in the longitudinal direction of the housing 21 are connected. The water supplied from the supply hole 23 passes through the U-shaped groove 412, reciprocates in the cooling block 41, and is discharged from the discharge hole 24. That is, the water passing through the first passage 412a arranged on the right side of FIG. 7 flows from the supply hole 23 toward the second end of the housing 21 (from the back of the page toward the front), and the left side The water passing through the two passages 412b flows toward the discharge hole of the casing 21 (from the front side of the paper to the back side). Each of the passages 412a and 4b has a rectangular cross section, and is disposed above each of the LED units 33.

  A rectangular lid member 42 is disposed on the upper surface 411 of the cooling block 41 so as to cover the groove 412, and a sheet-like heat insulating material 43 is disposed at a contact portion between the cooling block 41 and the lid member 42. ing. The lid member 42 is made of a material having high thermal conductivity such as aluminum or SUS, and extends in the longitudinal direction of the housing 21 so as to cover the entire U-shaped groove 412. Further, the heat insulating material 43 is disposed in a portion other than the groove 412 formed on the upper surface of the cooling block 41, and prevents the heat of the cooling block 41 from being conducted to the lid member 42. The heat insulating material 43 also plays a role of a gasket so that water flowing through the groove 412 is sealed by the lid member 42. As such a heat insulating material 43, for example, a heat insulating sheet material formed of a resin tetrafluoride ethylene resin having high heat resistance and high heat insulating properties, or a heat insulating sheet material formed of silicon rubber can be used. In addition, the sheet | seat material which plays only the role as a gasket can also be used, In that case, although the heat insulation effect becomes small, you may cover the whole upper surface of the cooling block 41. FIG.

  Next, the control unit 5 will be described with reference to FIGS. 6 and 7. As shown in FIG. 7, the control unit 5 has a pair of first heat conducting members 51 extending upward from the lid member 42, and controls the driving of the ultraviolet LED 32 to the first heat conducting member 51. A substrate 52 is supported. The control board 52 is composed of components such as FETs, coils, and diodes. In addition, a constant current circuit is disposed, and the power supplied from the power supply terminal 25 is supplied to each ultraviolet LED 32 with a set current value. In addition, a CPU, a communication circuit with the control board of the printer main body, a control circuit for the cooling fan, a circuit for recording the irradiation time of the ultraviolet LED 32, and the like are arranged and transmitted from the printer via the signal terminal 26. The driving of the ultraviolet LED 32 is controlled on the basis of the signal. The pair of first heat conducting members 51 do not necessarily have the same shape, and may have different shapes as shown in FIG.

  Each first heat conducting member 51 that supports the control board 52 is formed of a plate material having high heat conductivity such as aluminum or copper, and has a bottom portion 511 disposed on the lid member 42 and an upper end from one end of the bottom portion 511. It is formed in an L-shaped cross section including an extending portion 512 that extends. And the extension part 512 of both the 1st heat conductive members 51 is united so that it may oppose, and it has made the reverse T-shape. In other words, the combined extension portion 512 is disposed between the first and second passages 412a, 4b of the cooling block 41 and extends upward, and the bottom portions 511 are disposed so as to cover the passages 412a, b, respectively. ing. A control board 52 is attached to each extending portion 512 via an insulating material 53 having thermal conductivity, and each control board 52 is disposed so as to face both sides of the housing 21. With such a structure, an air cooling space F through which air for air cooling flows is formed between the inner wall surfaces on both sides of the housing 21 and the control board 52.

  Further, on the bottom 511 of each first heat conducting member 51, a second heat conducting member 54 that contacts the control board 52 is attached. Each second heat conducting member 54 is in contact with the bottom 541 that contacts the first heat conducting member 51, the L-shaped step 542 that forms a space between the control board 52, and the lower part of the control board 52. It is formed by connecting the parts 543. Therefore, the second conductive member 54 can also conduct the heat of the control board 52 to the lid member 42 via the first conductive member 51. In addition, although illustration is abbreviate | omitted, the sheet | seat material similar to the insulating material 54 mentioned above is provided also between the contact part 543 of the 2nd heat conductive member 54, and the control board 52. FIG. As such a sheet material, for example, a known heat dissipation silicon sheet can be used.

  As described above, the air cooling space F is formed in the control unit 5. However, as shown in FIG. 6, a cooling fan for flowing air into the air cooling space F is provided at the second end of the casing 21. 55 is attached. As such a cooling fan 55, a known axial fan can be used. When this cooling fan 55 is driven, air in the air cooling space F is discharged from the exhaust port 28 at the second end via the cooling fan 55. It has come to be.

  Next, the operation of the ultraviolet irradiation device configured as described above will be described. First, when the printing material P is conveyed in the printing press, ink is applied to the printing material P by the printing units 1K, 1C, 1M, 1Y, and 1P. Specifically, as shown in FIG. 1, the ink supplied from each ink supply device 11 to the plate cylinder 12 is transferred to the rubber cylinder 13 and then passes between the rubber cylinder 13 and the impression cylinder 14. It is applied to the substrate P. Immediately thereafter, the ink on the printing material P is cured by the ultraviolet rays irradiated from the ultraviolet irradiation device 2, and sent to the next printing unit 1 by the transfer cylinder 15. In each printing unit 1, ink is applied and cured in the same manner, the inks are superimposed and a full-color image is formed, and then conveyed outside the printing press.

  In the ultraviolet irradiation device, water is supplied to the cooling block 41 prior to the start of printing. The temperature of the water supplied from the supply hole 23 can be about 25 ° C., and water having a temperature higher by about 5 to 10 ° C. is discharged from the discharge hole 24 by heat exchange described later. In addition, by supplying power, the ultraviolet LED 32 emits ultraviolet light, and the irradiation intensity of the ultraviolet LED is adjusted by the control board 52 in accordance with a signal from the printing press. Thus, while the ultraviolet irradiation device 2 is driven, heat generated by the ultraviolet LED 32 is exchanged with water via the cooling block 41, and the ultraviolet LED 32 is cooled. Further, the heat generated in the control board 52 is also cooled by exchanging heat with water via the first and second heat conducting members 51 and 54 and the lid member 42. At this time, since the first and second heat conducting members 51 and 54 are disposed above the groove 412 through which water flows, the heat generated in the control board 52 can be efficiently conducted to water. In particular, since the first and second heat conducting members 51 and 54 are arranged so as to sandwich the control board 52, heat is transmitted from both the front and back surfaces of the control board 52. Therefore, the cooling effect is high. Further, as shown in FIG. 5, by driving the cooling fan 55, air X flows from the air inlet 27 formed at the first end of the housing 21, and the air cooling space F in the housing 21 is moved in the longitudinal direction. While passing, the air is discharged from the exhaust port 28 at the second end. In this process, the control board 52 is cooled not only by the cooling block 41 but also by the circulating air X.

  As described above, according to the present embodiment, since the first reflecting portions 611 and 621 facing the substrate P are provided at the lower ends of the reflecting members 61 and 62, as shown in FIG. The ultraviolet rays reflected from the printing material P can be reflected to the printing material P side by the first reflecting portions 611 and 621 (see dotted arrows). As a result, the illuminance of ultraviolet rays on the substrate P can be further improved.

  Moreover, in this embodiment, since the LED units 34 of 2 rows are arrange | positioned at predetermined intervals, the ultraviolet-ray irradiated from each LED unit 34 is piled up among these. Thereby, the illumination intensity of the ultraviolet rays received by the substrate P between the LED units 34 can be further improved. Since the reflection from the printing material P becomes large at the places where the illuminance is high in this way, if the first reflecting portion 621 is provided between the adjacent LED units 34 as described above, the reflected light is further reflected. Thus, the printing material P can be irradiated.

There are also the following effects. As the ultraviolet light emitted from the ultraviolet LED 32 is further away from the LED 32, the incident angle to the printed material P becomes larger, and when the ultraviolet ray is more than a predetermined reference angle α, the amount of reflection from the printed material P increases, The irradiation amount to the printing material P that has an influence becomes weak. As a result, the ink may not be hardened. On the other hand, in this embodiment, as shown in FIG. 13, if there is no reflecting member, ultraviolet light R ₀ having an incident angle θ from the ultraviolet LED 32 to the printed material P equal to or larger than the reference angle α is transmitted to each first reflecting portion. Reflected by 611 and 621 so that the incident angle γ is smaller than the reference angle α (see reference numeral R ₁ ). Thereby, the weak ultraviolet rays which do not contribute to the curing of the ink can be prevented from being irradiated to the printing material P, and the illuminance of the ultraviolet rays on the printing material P can be improved. As a result, the ink can be effectively cured. In this embodiment, since the stain prevention plate 37 is formed of quartz glass or the like, when the irradiated ultraviolet rays enter the stain prevention plate 37, total reflection occurs on the lower surface of the stain prevention plate 37, and the substrate P There is a possibility that ultraviolet rays are not irradiated to the side. On the other hand, when the reflector as described above is arranged between the light source unit 33 and the anti-stain plate 37, total reflection in the anti-stain plate 37 can be prevented, and ultraviolet rays from the LED can be printed. It is possible to reliably irradiate P. Such an effect can be obtained in the same manner even when a lens is disposed between the light source and the substrate.

  Moreover, as shown in FIG. 13, the position of the 1st reflection parts 611 and 621 is set as follows. That is, the ultraviolet rays irradiated near the lower ends of the first reflecting portions 611 and 621 have an incident angle β with respect to the printing material P and are smaller than the reference angle α. In the present embodiment, the lower ends of the first reflecting portions 611 and 621 are extended downward so as to be separated from the LED unit, so that ultraviolet rays having an incident angle smaller than the reference angle are also reflected. By doing so, it is possible to irradiate the ultraviolet light directly near the LED unit, so that the peak ultraviolet illuminance can be improved.

  Furthermore, the following effects can also be obtained. In general, it is known that when a reflector is formed in an elliptical shape and a light source is arranged in the vicinity of the focal point on one end side of the major axis of the ellipse, the light is condensed on the focal point on the other end side of the major axis. However, as in the present embodiment, when the light source is not a point light source but an ultraviolet LED having a certain size, the light source is not focused at one point of focus but has a certain width in the vicinity of the focus. Ultraviolet rays that approximate the parallel light are irradiated. For this reason, if an elliptical reflector is used, light that is close to parallel light is irradiated onto the substrate (for example, see V in FIG. 14). On the other hand, when the plate material is bent so that the second reflecting portions 612 and 622 form a part of the approximate ellipse E as in the present embodiment, the ultraviolet rays further dispersed than the parallel light are irradiated. be able to. Thereby, since the ultraviolet-ray irradiated to the to-be-printed material P is disperse | distributed rather than parallel light (for example, refer code | symbol U of FIG. 14), the integrated light quantity which the to-be-printed material P receives can be increased.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, in the above-described embodiment, the reflecting member composed of the first and second reflecting portions is used, but a reflecting member constituted only by the first reflecting portion can also be used. Moreover, although the 2nd reflection part is formed in two folds, it is not limited to this, You may make it approximate to an ellipse by making a crease into 1 or 3 or more. Further, instead of the plate material, for example, a part of the block can be cut out to form the reflection surface. Moreover, as shown in FIG. 15, the 2nd reflection parts 612 and 622 can also be formed along the inclined ellipse. In the example of the figure, the major axis Y of the two ellipses E is inclined so as to intersect on the substrate P side. When the second reflecting portions 612 and 622 of the reflecting members 61 and 62 are formed along the ellipse E, the high illuminance portions directly below the ultraviolet LEDs 32 are overlapped in close proximity to each other, thereby increasing the peak illuminance. be able to.

  In the above embodiment, the ultraviolet LED 32 is used. However, the ultraviolet LED 32 is not particularly limited as long as it can irradiate ultraviolet rays. For example, an ultraviolet laser diode or a laser light source that emits ultraviolet rays can be used. Furthermore, in the said embodiment, although the ultraviolet irradiation device which concerns on this invention was applied to the printing machine, as long as ultraviolet rays are irradiated, a to-be-irradiated object is not specifically limited.

  Examples of the present invention will be described below. However, the present invention is not limited to the following examples.

As shown in FIG. 16, by using a UV irradiation device in which two sets of LED units each having two rows of UV LEDs in the direction of conveyance of the substrate to be printed are arranged at a predetermined interval, as shown in the above embodiment, a simulation is performed. The reflective member was evaluated. The simulation conditions were as follows, and the illuminance of ultraviolet rays received by the irradiated object was calculated.
(1) LED: Nichia LED “NC4U134”, power consumption is 14.8 [v (voltage)] × 0.5 [A (voltage)] = 7.4w
(2) Ultraviolet LED, shape of reflecting member, etc .: as shown in FIG. 16 (3) Ink: radical type ultraviolet curable ink (UV OFS LED series (manufactured by T & K TOKA))
(4) Reflectance: The reflectance of the reflecting member was set to 95%, and the reflectance of the printing material was set to 50%.

  First, as shown in FIG. 17A, the illuminance received by the printing material was measured using a comparative example in which each reflection member did not have the first reflection part but only the second reflection part. The result is as shown in FIG. The horizontal axis is the position in the transport direction, and the vertical axis is the illuminance of ultraviolet rays received by the substrate. According to the figure, the illuminance is the strongest directly under each LED unit, and the illuminance decreases with increasing distance in the transport direction. However, since two LED units are used in this example, in the portion where the light of both overlaps, that is, between the two LED units, the ultraviolet light is superimposed and the illuminance is increased.

  Subsequently, as shown in FIG. 18A, an example using a reflecting member having first and second reflecting portions was evaluated. The result is as shown in FIG. In the figure, the dotted line indicates the illuminance when the first reflecting portion is provided, and is superimposed on FIG. 17B for comparison. As a result, it can be seen that the illuminance between the LED units W is greatly improved. Moreover, the influence of the reflection by the 1st reflection part appears in the whole irradiation range of an ultraviolet-ray, for example, the peak illumination intensity just under an LED unit is improving (arrow P). Moreover, although the illuminance is reduced at a position away from the LED unit (arrow M), the illuminance is improved near the peak (arrow J). This seems to be because ultraviolet rays are reflected directly below the LED by the first reflecting portion. Therefore, it was found that by providing the first reflecting portion, the illuminance received by the substrate is improved without increasing the output of the LED.

32 UV LED (UV light source)
33 LED unit (light source unit)
61, 62 Reflecting members 611, 621 First reflecting portion 612, 622 Second reflecting portion α Reference angle γ Incident angle
E Ellipse

Claims (6)

An ultraviolet irradiation device for irradiating an object with ultraviolet rays,
At least one light source unit having a plurality of ultraviolet light sources arranged along the irradiation object width direction orthogonal to the conveyance direction of the irradiation object;
A pair of reflecting members disposed between the light source unit and the irradiated object and disposed so as to sandwich the light source units from the upstream side and the downstream side in the transport direction,
Each said reflection member is an ultraviolet irradiation device which has the 1st reflection part which opposes the said to-be-irradiated object. A plurality of the light source units are arranged along the transport direction at a predetermined interval,
2. The ultraviolet irradiation device according to claim 1, wherein the first reflecting portions of the reflecting members arranged between the adjacent light source units form a reflecting surface that is continuous along the transport direction. In each of the reflecting members, a plurality of the first reflecting portions are provided at predetermined intervals along the irradiated object width direction.
The two adjacent reflecting members between the light source units are disposed so that the first reflecting portions are engaged with each other, thereby forming a reflecting surface that is continuous along the transport direction. UV irradiation device. Each of the reflecting members has a second reflecting portion that extends from the ultraviolet light source toward the substrate,
All or at least a part of the second reflecting portion has a weak ultraviolet ray whose incident angle from the ultraviolet light source to the printing material is equal to or larger than a predetermined reference angle and hardly contributes to curing inside the ink. The ultraviolet irradiation device according to claim 1, wherein the ultraviolet irradiation device reflects light so as to be smaller than the reference angle.   Each said reflection member is formed with a board | plate material, The said 1st reflection part and the 2nd reflection part are formed by bending each said reflection member along the crease | fold which extends in the said width direction. The ultraviolet irradiation device described. At least one of the second reflecting portions facing each other with the light source unit interposed therebetween approximately forms a part of an ellipse in cross section,
The ultraviolet light irradiation device according to claim 4, wherein the light source unit is arranged in the vicinity of one focal point of the ellipse in a cross section.

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