Drying device

Abstract

A drying device (11) comprises: a cooling body (16) that includes a contact portion (18) that comes into contact with the rear surface of a base material (12); and a near-infrared irradiation device (31) that irradiates the front surface of the base material with near-infrared rays. A paste (13) is applied to the front surface of the base material. The near-infrared irradiation device is arranged at a position from which it is possible to irradiate the contact portion with near-infrared rays. The contact area (α) between the contact portion and the rear surface of the base material is equal to or larger than the effective irradiation area (β), which is the area of the irradiation range on the front surface of the base material, said range being that irradiated with near-infrared rays.

Description

Drying device

[0007] ,

[0001] The present invention relates to a drying device for firing a paste applied to a substrate.

[0002] Conventionally, as a device manufacturing technology in the electronics field, printed electronics (PE) using printing technology has been used. It is known that by using this technology, it is possible to reduce waste liquid and material loss in the formation of circuit patterns and electrodes. Circuit patterns and electrodes by printed electronics are manufactured through processes such as pattern formation, drying, and cooling using a functional paste. In the drying process, generally, lamp annealing using infrared rays or the like is the mainstream.

[0003] In recent years, as a new type of substrate, a flexible resin substrate using resins such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) has been devised. Since this type of material has low heat resistance, in the conventional heating by infrared irradiation, the irradiation intensity cannot be increased. Therefore, as disclosed in Patent Document 1, a method of irradiating near-infrared rays is adopted as a method of promoting the heat generation of metals and the like contained in the paste and making it difficult to promote heat generation in the resin.

[0004] When drying the paste with near-infrared rays, the substrate is not heated so much as to be deformed directly by the irradiation of near-infrared rays. However, the substrate may be deformed by the heat of the paste heated by near-infrared rays.

[0005] Japanese Patent Application Laid-Open No. 2013-146707

[0006] An object of the present invention is to provide a drying device capable of preventing deformation of a substrate while performing irradiation with near-infrared rays.

[0007] The present invention comprises a cooling body including a contact portion configured to contact the back surface of a substrate, including a surface to which paste has been applied, and a near-infrared irradiation device configured to irradiate the surface of the substrate with near-infrared light, wherein the near-infrared irradiation device is positioned to irradiate the contact portion with near-infrared light, and the contact area between the contact portion and the back surface of the substrate is equal to or greater than the effective irradiation area, which is the area of ​​the irradiation range on the surface of the substrate to which the near-infrared light is irradiated.

[0008] According to the present invention, it is possible to provide a drying apparatus that can prevent deformation of the substrate while irradiating it with near-infrared light.

[0009] Figure 1 is a side view showing a drying apparatus that is a first embodiment of the present invention. Figure 2 is a side view illustrating the contact area and effective irradiation area of ​​the contact portion. Figure 3 is a plan view illustrating the contact area and effective irradiation area of ​​the contact portion. Figure 4 is a plan view illustrating the contact area and effective irradiation area of ​​the contact portion. Figure 5 is a plan view illustrating the contact area and effective irradiation area of ​​the contact portion. Figure 6 is a side view showing a drying apparatus equipped with a plurality of lamps. Figure 7 is a side view showing a drying apparatus equipped with a preheating cooling unit. Figure 8 is a side view showing a drying apparatus equipped with a preheating cooling unit. Figure 9 is a side view showing a drying apparatus equipped with a tension holding unit. Figure 10 is a side view showing a drying apparatus equipped with a tension holding unit. Figure 11 is a plan view showing a tension holding roller. Figure 12 is a side view showing a drying apparatus equipped with a cooling body having an adhesive structure. Figure 13 is a side view showing a drying apparatus in which the temperature of the cooling body can be controlled. Figure 14 is a side view showing a drying apparatus in which the temperature of the cooling body can be controlled. Figure 15 is a side view showing a drying apparatus equipped with a re-dryer. Figure 16 is a side view showing a drying apparatus equipped with a re-dryer. Figure 17 is a side view showing a drying apparatus equipped with multiple drying units. Figure 18 is a side view showing a drying apparatus equipped with multiple drying units. Figure 19 is a side view showing a drying apparatus equipped with a belt-type substrate conveying device. Figure 20 is a side view showing a drying apparatus equipped with a belt-type substrate conveying device. Figure 21 is a side view showing a related drying apparatus.

[0010] As described above, when drying paste using near-infrared radiation, the substrate is not directly heated to the point of deformation by the near-infrared radiation. However, the heat from the paste heated by the near-infrared radiation could sometimes cause the substrate to deform.

[0011] As shown in Figure 21, when near-infrared IR is irradiated from the near-infrared irradiation device 1, the substrate 2 coated with paste 4 is moved while in contact with the rotating cooler 3, thereby eliminating thermal deformation of the substrate 2 to some extent. However, when near-infrared IR is irradiated to a portion 2a of the substrate 2 where a gap S exists between the substrate 2 and the cooler 3, cooling does not occur in this portion 2a, making it difficult to prevent deformation of the substrate 2.

[0012] This invention was made to solve these problems. Embodiments of the present invention will be described in detail below with reference to the drawings.

[0013] (First Embodiment) The drying apparatus 11 shown in Figure 1 dries a functional paste 13 (hereinafter simply referred to as paste 13) coated or printed on the front surface of a web-shaped substrate 12 extending from left to right in Figure 1, using near-infrared IR. The drying apparatus 11 includes a substrate transport section 14 for transporting the substrate 12 and a drying section 15 for drying the paste 13. The near-infrared light has a peak wavelength range of 0.8 to 1.7 μm.

[0014] The substrate 12 is a thin, strip-shaped film. The materials used to form the substrate 12 include, for example, glass, paper, cloth, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), PC (polycarbonate), copper, aluminum, silver, and gold. The thickness of the substrate 12 is, for example, 10 μm to 10 mm.

[0015] Paste 13 can be a mixture of metal nanoparticles such as gold, silver, copper, aluminum, nickel, zinc, tin, lithium, chromium, lead, iron, platinum, iridium, osmium, rhodium, tungsten, molybdenum, ruthenium, palladium, oxides and alloys thereof, or conductive carbon nanoparticles dispersed in a resin binder (protective agent, dispersant). Alternatively, paste 13 may be a mixture of methylammonium iodide or lead(II) iodide dissolved in a solvent such as dimethylformamide (DMF). The solvent may consist of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, water, or combinations thereof. Furthermore, an electrode slurry containing an active material, a conductive additive, a binder, and a dispersion medium can be used as paste 13.

[0016] The substrate transport section 14 of the drying apparatus 11 according to this embodiment is equipped with a cooling body 16 having a cylindrical appearance for transporting the substrate 12. The cooling body 16 is driven by a drive device (not shown) and rotates around a rotation axis 17 located at the axial center. When the cooling body 16 rotates clockwise in Figure 1 with the substrate 12 in contact with the outer circumferential surface of the cooling body 16, the substrate 12 is transported from left to right in Figure 1. In other words, the cooling body 16 functions as a transport mechanism for transporting the substrate 12. In the cooling body 16 according to this embodiment, its outer circumferential surface constitutes a contact portion 18 that contacts the back surface of the substrate 12.

[0017] The cooler 16 is made of a material having a thermal conductivity of 10 [W / m·K] or more. For example, the cooler 16 may be made of stainless steel, copper, red copper, brass, chromium copper, aluminum, duralumin, tungsten, titanium, carbon steel, chromium steel, nickel steel, chromium nickel steel, nickel chromium alloy, tungsten, silicon steel, gold, platinum, silver, ceramics, or combinations of the aforementioned materials.

[0018] The cooling body 16 is equipped with a temperature maintenance mechanism 19. The temperature maintenance mechanism 19 has the function of cooling the cooling body 16, whose temperature rises due to heat transferred from the paste 13 through the base material 12. Although not shown in detail, the temperature maintenance mechanism 19 can be a water-cooled type, an air-cooled type, a cooling type using a Peltier cooler as the heat absorption part, or a combination of these cooling types.

[0019] Examples of water-cooled cooling structures include the following first to third cooling structures. The first cooling structure has a path through which a cooling fluid flows inside the cooling body 16, and the cooling water, whose temperature is controlled by a cooling chiller, passes through it. The second cooling structure immerses the cooling body 16 in cooling water at a position lower than the contact surface with the base material 12. The third cooling structure contacts the outer circumferential surface of the cooling body 16 with a cooling roller.

[0020] In the transport direction of the base material 12, a first tension-holding member 21 is positioned upstream of the cooling body 16, and a second tension-holding member 22 is positioned downstream of the cooling body 16. The first and second tension-holding members 21 and 22 adjust the tension of the base material 12 to increase the area in close contact between the base material 12 and the cooling body 16. Hereinafter, the area of ​​the part of the base material 12 that is in contact with the cooling body 16 will simply be referred to as the "contact area α". The contact area α is calculated as (length of the part of the base material 12 that is in contact with the cooling body 16 in the circumferential direction of the outer surface of the cooling body 16) × (width of the base material 12 (length in the axial direction of the cooling body 16)).

[0021] The first tension-holding member 21 shown in Figure 1 is composed of a roller 23 that rotates while in contact with the back surface of the base material 12 to which paste 13 has not been applied. The first tension-holding member 21 increases the contact area α by applying a predetermined tension to the base material 12 that is stretched between the first tension-holding member 21 and the cooling body 16.

[0022] The second tension-holding member 22 is composed of a roller 25 that rotates while in contact with the surface of the base material 12. The second tension-holding member 22 defines the transport path of the base material 12 so that the base material 12 is sent directly downward from the cooler 16. In other words, the second tension-holding member 22 lowers the position where the base material 12 is separated from the cooler 16 as much as possible, thereby increasing the contact area α, which is the area in close contact between the base material 12 and the cooler 16.

[0023] In this embodiment, as shown in Figure 2, the substrate 12 is in contact with the cooler 16 over a range of approximately 1 / 4 of the entire circumference of the cooler 16. More specifically, the range in which the substrate 12 is in close contact with the cooler 16 is the range between the contact point P1, which is the point where the substrate 12, moving by conveyance, first comes into contact with the cooler 16, and the release point P2, which is the point where the substrate 12 separates from the cooler 16. In the drying section 15 shown in Figure 2, the angle θ between the imaginary line L1 extending from the axis C of the cooler 16 to the contact point P1 and the imaginary line L2 extending from the axis C of the cooler 16 to the release point P2 is 90 degrees.

[0024] A coating device 24 for printing or coating the paste 13 onto the substrate 12 is positioned near the top of the first tension-holding member 21. The coating device 24 usable in the drying apparatus 11 according to this embodiment may be a printing device such as a screen printing device, screen offset printing device, gravure printing device, gravure offset printing device, flexographic printing device, or an apparatus for performing coating methods such as a die coater, gravure coater, bar coater, slit coater, or spray coater.

[0025] If it is necessary to reduce the thickness of the pattern formed by paste 13, the thickness of the pattern before drying can be, for example, 0.5 μm to 200 μm. Also, if the thickness of the pattern does not need to be that thin, the thickness of the pattern before drying can be reduced to 1 mm or less by forming the pattern using, for example, a screen printing method.

[0026] When applying paste 13 to the substrate 12, if a printing or coating method is used that stops the transport of the substrate 12, such as screen printing, a buffer section can be provided upstream of the drying section 15 in the transport direction of the substrate 12. The buffer section can stop the progress of the substrate 12 in the transport direction by allowing it to sag due to gravity.

[0027] The drying section 15 is equipped with a near-infrared irradiation device 31 that irradiates the surface of the substrate 12, which is being transported in contact with the cooling body 16, with near-infrared rays (IR). The near-infrared irradiation device 31 is positioned to irradiate the contact portion 18 of the cooling body 16 that is in contact with the substrate 12 with near-infrared rays (IR). Although not shown in the figures, the near-infrared irradiation device 31 in this embodiment is equipped with a lamp that emits near-infrared rays (IR) and a reflector that reflects the near-infrared rays emitted from the lamp toward the object to be heated. The distance between the lamp and the cooling body 16 is preferably within 100 mm. This is because if the distance between the lamp and the cooling body 16 exceeds 100 mm, the near-infrared rays (IR) will scatter, causing uneven drying.

[0028] The near-infrared irradiation device 31 can be a parallel irradiation type that irradiates near-infrared IR in parallel, a linear irradiation type that focuses near-infrared IR in a linear direction, or a point irradiation type that focuses near-infrared IR in a point direction. In the drying apparatus 11 according to this embodiment, one of the above three irradiation types is used that is suitable for the thickness and pattern of the paste 13 on the substrate 12.

[0029] The near-infrared (IR) light is reflected by the mirror and directed toward the substrate 12, irradiating a wider area than the near-infrared irradiation device 31 when viewed from the direction opposite to the substrate 12. The area irradiated by the near-infrared (IR) light, when viewed from the direction opposite to the substrate 12, is as shown in Figure 3.

[0030] Figure 3 is a plan view showing the substrate 12 in contact with the outer circumferential surface of the cooling body 16, unfolded to a flat surface. In Figure 3, the left-right direction is the axial direction of the cooling body 16, and the up-down direction is the circumferential direction of the cooling body 16. The area of ​​the substrate 12 shown in Figure 3 is the contact area α described above.

[0031] Figure 3 shows an example of the irradiation range of near-infrared (IR). The near-infrared (IR) shown in Figure 3 irradiates an area where the effective irradiation area β is smaller than the contact area α. The effective irradiation area β is the area on the surface of the substrate 12 that is irradiated with near-infrared (IR). As shown in Figure 4, if the near-infrared (IR) irradiates a wider area than the substrate 12, then only the portion of the substrate 12 that is irradiated will have an effective irradiation area β. The portion of the substrate 12 that is irradiated with near-infrared (IR) is shown by the downward-sloping hatching in Figure 4.

[0032] The effective irradiation area β is preferably an area that can receive enough energy to cause the paste 13 on the substrate 12 to generate heat. The outer edge of the area irradiated with near-infrared IR has low energy, and the near-infrared IR irradiated here contributes little to the heating of the paste 13. For this reason, as shown in Figure 5, it is desirable that the effective irradiation area β be the area remaining after excluding the outer edge A of the irradiation range, which does not have enough energy to heat the paste. In Figure 5, the outer edge A of the irradiation range is indicated by hatching that is relatively wide and slopes downward to the left.

[0033] The drying apparatus 11 according to this embodiment is configured such that the contact area α and the effective irradiation area β satisfy the relationship α > β or α = β. In other words, the contact area α is greater than or equal to the effective irradiation area β. By adopting this configuration, the entire area of ​​the substrate 12 irradiated with near-infrared IR comes into contact with the cooling body 16, and even though the heat generated during the drying of the paste 13 is transferred to the substrate 12, the substrate 12 is reliably cooled by the cooling body 16. In other words, since near-infrared IR is not irradiated to the parts of the substrate 12 that are not in close contact with the cooling body 16, deformation of the substrate 12 due to insufficient cooling can be prevented.

[0034] The near-infrared irradiation device 31 may be equipped with multiple lamps 32, as shown in Figure 6. The near-infrared irradiation device 31 shown in Figure 6 is equipped with three lamps 32. In this case, the sum of the effective irradiation areas βa, βb, and βc of the three lamps 32 is considered to be the effective irradiation area β of the near-infrared irradiation device 31. Note that the area of ​​the overlapping irradiation ranges of each lamp 32 is not added to the effective irradiation area β. By using multiple lamps 32 as shown in Figure 6, the effective irradiation area β can be increased. Therefore, even when the paste 13 is coated thickly and over a wide area on the substrate 12, the transport speed can be maintained at a high speed.

[0035] The substrate 12 may deform due to residual heat after passing through the area irradiated with near-infrared IR. However, in the drying apparatus 11 according to this embodiment, when the contact area α is larger than the effective irradiation area β (α > β), the substrate 12 is in contact with the cooler 16 even downstream of the near-infrared IR irradiation range corresponding to the effective irradiation area β in the transport direction of the substrate 12. Therefore, as shown in Figure 7, after the paste 13 is dried by near-infrared IR irradiation, the heat of the substrate 12 can be removed by heat conduction to the cooler 16. In this case, the portion of the cooler 16 downstream of the near-infrared IR irradiation range in the transport direction of the substrate 12 constitutes a residual heat cooling section 33 that removes residual heat from the substrate 12. By cooling the substrate 12 in this residual heat cooling section 33, deformation of the substrate 12 can be prevented even more reliably.

[0036] To cool the substrate 12 on the cooling body 16, a residual heat removal device 33A, shown by the dashed line in Figure 7, can be used. The residual heat removal device 33A is positioned downstream of the near-infrared irradiation device 31 in the direction of transport of the substrate 12. More specifically, the residual heat removal device 33A is positioned opposite the portion of the cooling body 16 downstream of the near-infrared IR irradiation range in the direction of transport of the substrate 12. The residual heat removal device 33A cools the surface of the substrate 12 moving along the aforementioned portion of the cooling body 16 with a cooling medium (refrigerant). As the residual heat removal device 33A, a blower that blows gas (e.g., air) onto the surface of the substrate 12 or a sprayer that blows mist (e.g., water mist) onto the surface of the substrate 12 can be used. Note that it is also possible to cool only the surface of the substrate 12 using the residual heat removal device 33A.

[0037] The residual heat cooling section 33 can be constructed using the cooling body 16, or it can be implemented using a dedicated residual heat removal device 34 as shown in Figure 8. The residual heat removal device 34 shown in Figure 8 is positioned downstream in the conveying direction of the substrate 12 from the point where the substrate 12 separates from the cooling body 16. The residual heat removal device 34 cools the back surface of the substrate 12 with a cooling medium as it moves downstream in the conveying direction away from the cooling body 16. As the residual heat removal device 34, a blower that blows gas (e.g., air) onto the back surface of the substrate 12 or a sprayer that blows mist (e.g., water mist) onto the back surface of the substrate 12 can be used. By adopting this configuration and making it possible to increase or decrease the supply amount of the cooling medium, the cooling of the substrate 12 can be controlled according to the amount (heat generation) of the paste 13, thereby more reliably preventing deformation of the substrate 12.

[0038] The drying apparatus 11 shown in Figure 1 is equipped with a first tension-holding member 21 upstream of the substrate 12 in the conveying direction relative to the cooling body 16, and a second tension-holding member 22 downstream in the conveying direction. However, it is possible to increase the contact area α by equipping at least one of the first and second tension-holding members 22.

[0039] It is desirable that the first tension-holding member 21 is configured to hold the base material 12 without touching the undried paste 13. Such a first tension-holding member 21 can be configured as shown in Figures 9 to 11.

[0040] The first tension-holding member 21 shown in Figure 9 is composed of a roller 35 that rotates while the back surface of the base material 12 is attracted to it. Numerous suction holes 35a are opened on the outer circumferential surface of the roller 35 that contacts the back surface of the base material 12. The roller 35 rotates while drawing in air through these suction holes 35a. Note that the first tension-holding member 21 can be one on which the base material 12 is attracted by electrostatic attraction.

[0041] The first tension-holding member 21 shown in Figures 10 and 11 is a roller 38 comprising a pair of roller bodies 36 that contact both ends 12a in the width direction of the base material 12 (the parts not coated with paste 13), and a shaft 37 that connects these roller bodies 36. This roller 38 rotates while pressing against the surface of the base material 12.

[0042] Figure 10 shows a second tension-holding member 22, which is a blower 39 that uses the air pressure of air blown onto the surface of the substrate 12 to push the substrate 12 toward the cooling body 16. The blower 39 is positioned downstream of the cooling body 16 in the conveying direction of the substrate 12. By using this blower 39, the substrate 12 can be pressed and cooled simultaneously.

[0043] The second tension-holding member 22 can also be composed of a roller 40 that rotates without contact with the surface of the base material 12, as shown in Figure 9. The outer circumferential surface of the roller 40 has numerous ejection holes 40a for ejecting air. The roller 40 rotates without contact with the surface of the base material 12 while ejecting air from these ejection holes 40a.

[0044] Even after the paste 13 on the surface of the substrate 12 has dried, it may still be undesirable for a roller or the like to touch the surface of the substrate 12. In such cases, using the above-described configuration makes it possible to apply appropriate tension without touching the coated surface of the substrate 12.

[0045] By providing at least one of the first tension holding member 21 and the second tension holding member 22, the area where the base material 12 and the cooling body 16 are in close contact can be increased. For this reason, it becomes possible to increase the number of lamps 32 or expand the waste heat cooling part 33, and the drying efficiency is improved even in a space-saving manner.

[0046] As shown in FIG. 12, the cooling body 16 can be provided with an attachment structure 41 for attaching the base material 12 to the contact part 18 of the cooling body 16. The attachment structure 41 shown in FIG. 12 includes a large number of suction holes 43 that open to the contact part 18 and an air suction device 42 that sucks air from these suction holes 43. The suction holes 43 preferably open over the entire circumferential direction of the contact part 18. According to this attachment structure 41, the base material 12 is attached to the contact part 18 of the cooling body 16 by vacuum suction.

[0047] Although not shown in the drawings, it is also possible to provide an adhesive on the cooling body 16 and attach the base material 12 to the cooling body 16 with this adhesive, or it is also possible to attach it using the principle of electrostatic adsorption. As an attachment structure 41 using the principle of electrostatic adsorption, there is a method of applying a voltage to the cooling body and adsorbing the base material by Johnson-Larbeck force, Coulomb force, or other electrical forces.

[0048] The attachment structure 41 for attaching the base material 12 to the cooling body 16 can increase the degree of adhesion between the base material 12 and the cooling body 16, so the cooling efficiency of the base material 12 can be improved. Also, when transporting the base material 12, it is possible to prevent the occurrence of wrinkles and the like.

[0049] The temperature maintenance mechanism 19 of the cooling body 16 can adopt the configuration shown in FIG. 13 or FIG. 14. FIGS. 13 and 14 show an example in the case where a temperature change part 46 for changing the temperature of the cooling body 16 is provided on the cooling body 16. The temperature change part 46 is composed of a water-cooled cooler, an air-cooled cooler, a cooler of a cooling method having a Peltier cooler as a heat absorption part, a cooler combining these cooling methods, and the like.

[0050] The temperature maintenance mechanism 19 shown in Figures 13 and 14 comprises the temperature changing unit 46 described above, a temperature detection unit 47 that detects the temperature of the cooler 16 or the substrate 12, and a control unit 48 that controls the operation of the temperature changing unit 46. The temperature detection unit 47 shown in Figure 13 detects the surface temperature of the substrate 12 downstream of the area irradiated with near-infrared light (IR) in the transport direction of the substrate 12 using a temperature sensor 49. The temperature detection unit 47 shown in Figure 14 detects the surface temperature of the cooler 16 using a temperature sensor 50 at least one of the following locations: upstream of the contact point P1 where the substrate 12 first contacts the cooler 16 as it moves forward by transport, and downstream of the release point P2, which is the point where the substrate 12 separates from the cooler 16, in the transport direction of the substrate 12.

[0051] The control unit 48 (controller) controls the operation of the temperature change unit 46 based on the temperature detected by the temperature detection unit 47. More specifically, if the temperature detected by the temperature detection unit 47 is higher than a predetermined temperature, the control unit 48 controls the operation of the temperature change unit 46 so that the temperature of the cooler 16 decreases.

[0052] By controlling the temperature of the cooler 16 with the temperature maintenance mechanism 19 in this way, it becomes possible to maintain the temperature of the cooler 16 appropriately. Even if the temperature changing unit 46 is configured to cool the cooler 16 from the outside, the same effect as in the above case can be obtained by providing a temperature detection unit 47 and a control unit 48.

[0053] The drying apparatus 11 according to this embodiment may include additional dryers 44 and 45 facing the residual heat cooling unit 33, as shown in Figures 15 and 16. The additional dryer 44 shown in Figure 15 is positioned facing a portion of the cooling body 16 downstream of the near-infrared IR irradiation range in the transport direction of the substrate 12. The additional dryer 45 shown in Figure 16 is positioned facing the residual heat removal device 34. The residual heat removal device 34 is positioned downstream of the point where the substrate 12 separates from the cooling body 16 in the transport direction of the substrate 12, and is configured to spray a cooling medium onto the back surface of the substrate 12.

[0054] The additional dryers 44 and 45 are configured to further dry the paste 13 on the substrate 12 using a method different from near-infrared drying. For example, the additional dryers 44 and 45 can be composed of a far-infrared irradiation device that irradiates the paste 13 with far-infrared rays, or a hot air blower that blows hot air onto the paste 13.

[0055] Depending on the paste 13 coated on the substrate 12, it may be necessary to perform additional drying by another method in addition to drying by the near-infrared irradiation device 31. By providing the above-described additional dryers 44 and 45, it is not necessary to provide a separate drying device using a different method than near-infrared drying, and the drying device 11 becomes more compact. Furthermore, by utilizing the cooling effect of the residual heat cooling unit 33, additional drying can be performed while absorbing heat, thus preventing deformation of the substrate 12. In addition, the residual heat cooling unit 33 also suppresses the heat generated by near-infrared drying, so additional drying can be performed without problems even immediately after near-infrared irradiation.

[0056] (Second Embodiment) The drying apparatus 51 shown in Figures 17 and 18 comprises a plurality of drying sections 55 arranged in the direction of transport of the substrate 12. In these figures, the same or equivalent components as those described in Figures 1 to 16 are denoted by the same reference numerals, and detailed descriptions are omitted.

[0057] In the drying apparatus 51 shown in Figure 17, three drying sections 55 are arranged in the direction of transport of the substrate 12. Each drying section 55 includes one cooling body 16 and one near-infrared irradiation device 31. Between adjacent drying sections 15, a cooling device 52 (air cooler) is placed to blow cooling air onto the surface of the substrate 12. When cooling air is blown from this cooling device 52 onto the surface of the substrate 12, the substrate 12 is pushed downward by the air pressure, increasing the contact area α. This makes it possible to cool the substrate 12 and apply tension to the substrate 12. When there are multiple cooling bodies 16 in this manner, the total contact area α is the sum of the contact areas between each cooling body 16 and the substrate 12.

[0058] In the drying apparatus 51 shown in Figure 18, three drying sections 55 are arranged in the direction of transport of the substrate 12. Each drying section 55 includes one cooling body 16 and one or two near-infrared irradiation devices 31. Tension-holding members 54, consisting of rollers 53 that rotate in contact with the surface of the substrate 12, are positioned between adjacent cooling bodies 16 and downstream of the cooling body 16 located furthest downstream in the transport direction of the substrate 12 among the three cooling bodies 16. Rollers 38 shown in Figures 10 and 11 can be used for these rollers 53. Alternatively, rollers 40 shown in Figure 9, which rotate without contact with the surface of the substrate 12, can be used instead of rollers 53.

[0059] (Third Embodiment) The drying apparatus 61 shown in Figures 19 and 20 is configured to transport the substrate 12 by a belt-type substrate transport device 62. That is, a belt 63 is used as the cooling element 16. In Figures 19 and 20, the same or equivalent components as those described in Figures 1 to 16 are denoted by the same reference numerals, and detailed descriptions are omitted.

[0060] The belt 63 is wrapped around a plurality of rollers 64 arranged horizontally. The rollers 64 are driven by a drive mechanism (not shown) and rotate, causing the belt 63 to move in one direction. The base material 12 is placed on the belt 63, which is moving horizontally above the rollers 64, thereby conveying the base material 12.

[0061] Although not shown in detail, the belt 63 can be constructed by attaching numerous metal plates to a single, endless belt-shaped rubber belt body. The belt 63 can also be constructed by rotatably connecting numerous metal plates to each other to form an endless belt. An adhesive is provided on the surface of the metal plates. The base material 12 adheres to the metal plates by the adhesive and moves together with the metal plates.

[0062] As shown in Figure 19, the temperature maintenance mechanism 19 can be configured to bring a cooling roller 65 into contact with a metal plate on the surface of the belt. As shown in Figure 20, the temperature maintenance mechanism 19 can also be configured to immerse the lower half of the belt 63 in a liquid cooling medium 66 contained in a cooling tank 68.

[0063] By configuring the cooling body 16 with a belt 63, the contact area α between the substrate 12 and the cooling body 16 can be increased, allowing multiple near-infrared irradiation devices 31 to be used side by side. In this case as well, the sum of the effective irradiation areas of the multiple near-infrared irradiation devices 31 is defined as the effective irradiation area β. In the drying apparatus 61 shown in Figures 19 and 20, a roller 67 for supporting the substrate is provided below the coating apparatus 24.

[0064] The drying apparatus according to the present invention is not limited to the configurations shown in each embodiment, and may be realized by combining structures and devices used in other embodiments.

[0065] (Note) The drying apparatus described above can also be configured as follows.

[0066] The drying apparatus described in Appendix 1 comprises a cooling body including a contact portion configured to contact the back surface of a substrate, including the surface to which paste has been applied, and a near-infrared irradiation device configured to irradiate the surface of the substrate with near-infrared rays. The near-infrared irradiation device is positioned to irradiate the contact portion with near-infrared rays, and the contact area between the contact portion and the back surface of the substrate is equal to or greater than the effective irradiation area, which is the area of ​​the irradiation range on the surface of the substrate to which the near-infrared rays are irradiated.

[0067] The substrate may be in the form of a web. The cooling body may be cylindrical and configured to rotate around a rotation axis located at its axial center. In this case, the substrate is transported as the cooling body rotates while the substrate is in contact with the outer surface of the cooling body. Therefore, the cooling body functions as a transport mechanism for transporting the substrate. The outer surface of the cooling body also constitutes the contact area.

[0068] The drying apparatus described in Appendix 2 is the drying apparatus described in Appendix 1, wherein the near-infrared irradiation device includes a plurality of lamps, and the effective irradiation area is the sum of the effective irradiation areas of the plurality of lamps.

[0069] The drying apparatus described in Appendix 3 is a drying apparatus according to Appendix 1 or 2, further comprising a preheating and cooling section configured to remove heat from the substrate downstream in the transport direction of the substrate from the irradiation range of the near-infrared light corresponding to the effective irradiation area.

[0070] The cooling unit may be configured to transport the substrate.

[0071] The preheating and cooling section may include a portion of the cooling element located downstream of the near-infrared irradiation range in the substrate transport direction.

[0072] The residual heat cooling section may include a residual heat removal device positioned downstream of the near-infrared irradiation device in the substrate transport direction and configured to spray a cooling medium onto the substrate. The residual heat removal device may be positioned opposite the part of the cooling body downstream of the near-infrared irradiation range in the substrate transport direction and configured to spray a cooling medium onto the surface of the substrate. The residual heat removal device may be positioned downstream of the point where the substrate separates from the cooling body in the substrate transport direction and configured to spray a cooling medium onto the back surface of the substrate. The residual heat removal device may include at least one of a blower for spraying gas onto the substrate and a sprayer for spraying mist onto the substrate.

[0073] The drying apparatus described in Appendix 4 is a drying apparatus according to any one of Appendix 1 to 3, wherein a tension-holding member configured to adjust the tension of the substrate is provided at least one upstream and downstream of the cooling body in the conveying direction of the substrate.

[0074] The tension-holding member may include a roller configured to rotate while in contact with the back or front surface of the base material. The roller may include an outer circumferential surface configured to contact the back surface of the base material, and a plurality of suction holes provided on the outer circumferential surface for drawing in air. The roller may also include a pair of roller bodies configured to contact both ends of the base material in the width direction, and a shaft configured to connect the pair of roller bodies.

[0075] The tension-holding member may include a wind pressure device (blower) configured to push the substrate toward the cooling body by blowing air onto the surface of the substrate. The wind pressure device may be positioned downstream of the cooling body in the direction of substrate transport.

[0076] The tension-holding member may include an outer surface having a plurality of ejection holes for ejecting air, and may include a roller configured to rotate non-contact with the surface of the substrate while ejecting air from the ejection holes.

[0077] The drying apparatus described in Appendix 5 is a drying apparatus according to any of Appendix 1 to 4, wherein the cooling body has an adhesive structure configured to attach the substrate to the contact portion.

[0078] The adhesive structure may include a plurality of suction holes formed in the contact portion and an air suction device configured to draw air from the plurality of suction holes.

[0079] The drying apparatus described in Appendix 6 is a drying apparatus according to any one of Appendix 1 to 5, comprising a temperature changing unit configured to change the temperature of the cooling body, a temperature detection unit configured to detect the temperature of the cooling body or substrate, and a control unit configured to control the operation of the temperature changing unit based on the temperature detected by the temperature detection unit.

[0080] The temperature changing unit may include a cooler configured to cool the cooling element. The cooler may include at least one of the following: a water-cooled cooler, an air-cooled cooler, and a cooler using a Peltier cooler as the heat absorption element.

[0081] The temperature detection unit may include a temperature sensor configured to detect the surface temperature of the substrate, positioned downstream of the near-infrared irradiation range in the substrate transport direction. The temperature detection unit may include a temperature sensor configured to detect the temperature of the contact area of ​​the cooling body before it comes into contact with the substrate, positioned upstream of the near-infrared irradiation range in the substrate transport direction. The temperature detection unit may include a temperature sensor configured to detect the temperature of the contact area of ​​the cooling body after it has separated from the substrate, positioned downstream of the near-infrared irradiation range in the substrate transport direction.

[0082] The control unit may include a controller configured to control the operation of the temperature change unit so that the temperature of the cooling body decreases when the temperature detected by the temperature detection unit is higher than a predetermined temperature.

[0083] The drying apparatus described in Appendix 7 is the drying apparatus described in Appendix 3, further comprising a re-dryer positioned opposite the preheating and cooling section and configured to re-dry the paste using a method different from near-infrared drying.

[0084] The additional dryer may be positioned opposite the part of the cooling body located downstream of the near-infrared irradiation range in the direction of substrate transport. The additional dryer may be positioned opposite a residual heat removal device configured to blow a cooling medium onto the back surface of the substrate, located downstream of the point where the substrate separates from the cooling body in the direction of substrate transport. The additional dryer may include a far-infrared irradiation device that irradiates the paste with far-infrared rays, or a hot air blower that blows hot air onto the paste.

[0085] The drying apparatus described in Appendix 8 is a drying apparatus according to any of Appendix 1 to 7, each comprising a plurality of drying sections, each including the cooling body and the near-infrared irradiation device, and the plurality of drying sections being arranged in the direction of transporting the substrate.

[0086] The drying apparatus may further include a cooler, which is positioned between adjacent drying sections of a plurality of drying sections and configured to blow cooling air onto the surface of the substrate. The drying apparatus may also include a tension-holding member, which includes rollers, positioned between adjacent drying sections of a plurality of drying sections and configured to rotate while in contact with the surface of the substrate.

[0087] The drying apparatus described in Appendix 9 further comprises a belt-type substrate conveying device including a plurality of rollers and a belt wrapped around the plurality of rollers, and the cooling body is composed of the belt, and is a drying apparatus according to any of Appendix 1 to 7.

[0088] The belt may include a plurality of metal plates. The drying apparatus may further include an adhesive applied to the surfaces of the plurality of metal plates of the belt. The drying apparatus may further include cooling rollers configured to contact the plurality of metal plates of the belt. The drying apparatus may further include a refrigerant tank configured to contain a cooling medium in which a portion of the belt is immersed.

[0089] 11, 51, 61... Drying device, 12... Substrate, 13... Paste, 16... Cooling body, 18... Contact part, 21... First tension-holding member, 22... Second tension-holding member, 31... Near-infrared irradiation device, 32... Lamp, 33... Preheating cooling unit, 35... Roller, 39... Air pressure device, 41... Adhesion structure, 42... Air suction device, 46... Temperature change unit, 48... Control unit.

Claims

1. A drying apparatus comprising: a cooling body including a contact portion configured to contact the back surface of a substrate including a surface to which paste has been applied; and a near-infrared irradiation device configured to irradiate the surface of the substrate with near-infrared rays, wherein the near-infrared irradiation device is positioned to irradiate the contact portion with near-infrared rays, and the contact area between the contact portion and the back surface of the substrate is greater than or equal to the effective irradiation area, which is the area of ​​the irradiation range on the surface of the substrate to which the near-infrared rays are irradiated.

2. A drying apparatus according to claim 1, wherein the near-infrared irradiation device includes a plurality of lamps, and the effective irradiation area is the sum of the effective irradiation areas of the plurality of lamps.

3. A drying apparatus according to claim 1 or 2, further comprising a preheating and cooling section configured to remove heat from the substrate downstream of the irradiation range of the near-infrared light corresponding to the effective irradiation area in the conveying direction of the substrate.

4. A drying apparatus according to claim 1 or 2, characterized in that a tension-holding member configured to adjust the tension of the substrate is provided at least one upstream and downstream of the cooling body in the conveying direction of the substrate.

5. A drying apparatus according to claim 1 or 2, characterized in that the cooling body comprises an adhesive structure configured to attach the substrate to the contact portion.

6. A drying apparatus according to claim 1 or 2, comprising: a temperature changing unit configured to change the temperature of the cooling body; a temperature detection unit configured to detect the temperature of the cooling body or substrate; and a control unit configured to control the operation of the temperature changing unit based on the temperature detected by the temperature detection unit.

7. A drying apparatus according to claim 3, further comprising a re-dryer arranged opposite to the preheating and cooling section and configured to re-dry the paste in a manner different from near-infrared drying.

8. A drying apparatus according to claim 1 or 2, characterized in that it comprises a plurality of drying sections, each including the cooling body and the near-infrared irradiation device, and the plurality of drying sections are arranged in the direction of transporting the substrate.

9. A drying apparatus according to claim 1 or 2, further comprising a belt-type substrate conveying device including a plurality of rollers and a belt wrapped around the plurality of rollers, wherein the cooling body is composed of the belt.

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