Dielectric heating device and printing system

Abstract

To provide a technique capable of suppressing retention of steam generated by heating an object to be heated in a dielectric heating device.SOLUTION: A dielectric heating device includes a conveying unit that conveys an object to be heated, an electrode unit including a first electrode and a second electrode to which an alternating voltage is applied, facing in a second direction intersecting the first direction with respect to the object to be heated conveyed in the first direction, and a metal first cover portion surrounding the electrode unit. The first cover portion includes a first insertion port for inserting the object to be heated into the first cover portion, a first delivery port for delivering the object to be heated to the outside of the first cover portion, and a plurality of first openings different from the first insertion port and the first delivery port.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a dielectric heating device and a printing system. [Background technology]

[0002] Patent Document 1 discloses a microwave heating device equipped with an electromagnetically shielded rectangular parallelepiped metal casing. In this heating device, an object to be heated is heated by microwaves inside the casing. The casing is provided with an opening for receiving the object to be heated and an opening for delivering the object to be heated, and each opening is sealed to prevent microwave leakage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-213962 Summary of the Invention [Problem to be solved by the invention]

[0004] When an object to be heated is heated inside a casing to prevent electromagnetic wave leakage, steam generated by heating may remain inside the casing. This may result in, for example, liquid produced by condensation of the remaining steam contaminating the object to be heated, or in reduced drying efficiency when the object to be heated is heated and dried. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a dielectric heating device comprising: a transport section for transporting an object to be heated; an electrode unit having first and second electrodes to which an AC voltage is applied, the electrode unit facing the object to be heated transported in a first direction in a second direction intersecting the first direction; and a metal first cover section surrounding the electrode unit. The first cover section has a first insertion opening for inserting the object to be heated into the first cover section, a first delivery opening for delivering the object to the outside of the first cover section, and a plurality of first openings different from the first insertion opening and the first delivery opening.

[0006] According to a second aspect of the present disclosure, there is provided a dielectric heating device comprising: a transport unit that transports an object to be heated; an electrode unit that faces the object to be heated transported in a first direction in a second direction intersecting the first direction and has first and second electrodes to which an AC voltage is applied; a transport unit that is configured to reciprocate the electrode unit in a fifth direction intersecting the first direction and orthogonal to the second direction; a metal fourth cover unit that faces the object to be heated transported in the first direction in the second direction and covers the electrode unit; and a metal opposing unit that faces the first and second electrodes across the object to be heated in a direction along the second direction. The fourth cover unit is configured to reciprocate in the fifth direction together with the electrode unit, and has a fifth opening that opens in the second direction toward the object to be heated and surrounds the first and second electrodes when viewed along the second direction.

[0007] According to a third aspect of the present disclosure, there is provided a printing system including the dielectric heating device of the above aspect and a liquid ejection unit that ejects liquid onto a print medium, and the transport unit transports the print medium with the liquid attached thereto as the object to be heated. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a schematic configuration of a dielectric heating device in a first embodiment. [Figure 2]FIG. 2 is a perspective view showing a schematic configuration of an electrode unit. [Figure 3] 3 is a cross-sectional view of the first electrode taken along line III-III in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the first electrode taken along line IV-IV in FIG. 2. FIG. [Figure 5] FIG. 2 is a perspective view showing a schematic configuration of a first cover portion. [Figure 6] FIG. 6 is a schematic diagram showing the general configuration of a dielectric heating device in a second embodiment. [Figure 7] FIG. 4 is a perspective view showing a schematic configuration of a second cover portion. [Figure 8] FIG. 10 is a perspective view showing a schematic configuration of a dielectric heating device according to a third embodiment. [Figure 9] FIG. 10 is a schematic diagram showing the general configuration of a dielectric heating device according to a fourth embodiment. [Figure 10] FIG. 10 is a perspective view showing a schematic configuration of a dielectric heating device according to a fifth embodiment. [Figure 11] FIG. 10 is a schematic diagram showing a schematic configuration of a dielectric heating device in a fifth embodiment. [Figure 12] FIG. 4 is a perspective view showing a schematic configuration of a third cover portion. [Figure 13] FIG. 10 is a perspective view showing a schematic configuration of a dielectric heating device in a sixth embodiment. [Figure 14] FIG. 10 is a schematic diagram showing the general configuration of a dielectric heating device in a sixth embodiment. [Figure 15] FIG. 12 is a schematic diagram showing the general configuration of a dielectric heating device in a seventh embodiment. [Figure 16] FIG. 13 is a perspective view showing a schematic configuration of a fourth cover part in the seventh embodiment. [Figure 17] FIG. 13 is a schematic diagram showing the general configuration of a printing system according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: FIG. 1 is a perspective view showing the schematic configuration of a dielectric heating device 100 according to the first embodiment. Arrows indicating mutually orthogonal X, Y, and Z directions are shown in FIG. 1. The X and Y directions are parallel to a horizontal plane, and the Z direction is a vertically upward direction. The arrows indicating the X, Y, and Z directions are also shown in other figures as appropriate so that the illustrated directions correspond to those in FIG. 1. In the following description, when specifying the direction, positive and negative signs are used in combination to indicate the direction indicated by the arrow in each figure, with "+" indicating the direction indicated by the arrow and "-" indicating the opposite direction. Hereinafter, the +Z direction will also be referred to as "up" and the -Z direction as "down." Furthermore, in this specification, "orthogonal" includes a range of 90°±10°.

[0010] The dielectric heating device 100 includes an electrode unit 20 for heating the object OH, a transport section 200 for transporting the object OH, a case section 300 for accommodating the electrode unit 20, a voltage application section 80 for applying an AC voltage to the electrode unit 20, and a control section 500. In this embodiment, the case section 300 is configured by a first cover section 310 made of metal that surrounds the electrode unit 20.

[0011] The dielectric heating device 100 heats the object OH by an electric field generated by the electrode unit 20 within the first cover part 310 while transporting the object OH by the transport part 200. In this embodiment, the dielectric heating device 100 dries the object OH by heating a sheet-like print medium to which a liquid has been applied, which serves as the object OH. Examples of print media that can be used include paper, cloth, and film. Examples of liquids that can be applied to the print medium include various inks whose main component is water or an organic solvent. The liquid is applied to the print medium by a liquid ejection device such as an inkjet printer.

[0012] The control unit 500 is configured by a computer equipped with one or more processors, a storage device, and an input / output interface for inputting and outputting signals from and to the outside. The control unit 500 controls each unit, such as the transport unit 200 and voltage application unit 80, described above, to heat the object OH in the dielectric heating device 100. The control unit 500 may be configured by multiple computers.

[0013] The conveying unit 200 in this embodiment has two conveying rollers 205 and a driving unit (not shown) configured by a motor or the like that drives the conveying rollers 205. The conveying unit 200 conveys the sheet-like object to be heated OH by driving the conveying rollers 205.

[0014] The object to be heated OH is inserted into the first cover part 310 through a first insertion opening 312 provided in the first cover part 310 while being transported by the transport part 200. Then, the object to be heated OH is heated by the electrode unit 20 inside the first cover part 310 while being transported in the same manner, and then is sent out of the first cover part 310 through a first delivery opening 314 provided in the first cover part 310. Details of the case part 300 will be described later.

[0015] 2 is a perspective view showing a schematic configuration of the electrode unit 20 in this embodiment. The electrode unit 20 has a first electrode 30 and a second electrode 40. Furthermore, the electrode unit 20 in this embodiment has a coil 50.

[0016] The first electrode 30 and the second electrode 40 are both electrically connected to the voltage application unit 80 shown in Fig. 1. In this embodiment, the first electrode 30 is electrically connected to the voltage application unit 80 via an electric wire 75, a coil 50, and an inner conductor 70 of a coaxial cable. The second electrode 40 is electrically connected to the voltage application unit 80 via an outer conductor of a coaxial cable (not shown).

[0017] The first electrode 30 and the second electrode 40 are conductors, and are formed from, for example, a metal, an alloy, a conductive oxide, or the like. The first electrode 30 and the second electrode 40 may be formed from the same material or different materials. For example, to maintain their posture and strength, the first electrode 30 and the second electrode 40 may be placed on a substrate or the like formed from a material with low dielectric tangent or conductivity, or may be supported by another member. As shown in FIG. 2 , in this embodiment, the second electrode 40 is supported from above by a support member 60.

[0018] The first electrode 30 and the second electrode 40 are arranged so that the shortest distance between them is one-tenth or less of the wavelength of the electromagnetic field output from the electrode unit 20. In this embodiment, the first electrode 30 has a boat-like shape with the X direction as the longitudinal direction and the Y direction as the transverse direction. The lower surface of the first electrode 30 has a curved shape that is convex in the -Z direction. When viewed along the Z direction, the first electrode 30 has an oval shape that is long in the X direction. The second electrode 40 is flat in the X and Y directions and has an oval ring shape that is long in the X direction. When viewed along the Z direction, the second electrode 40 is arranged to surround the periphery of the first electrode 30.

[0019] The first electrode 30 and the second electrode 40 are both disposed on a substrate 110 that is disposed parallel to the X and Y directions. More specifically, the first electrode 30 is disposed so that the central portion of the lower surface of the first electrode 30 in the X and Y directions is in contact with the upper surface of the substrate 110. The second electrode 40 is disposed so that the lower surface of the second electrode 40 is in contact with the upper surface of the substrate 110. Therefore, in this embodiment, the central portion of the lower surface of the first electrode 30 and the lower surface of the second electrode 40 are disposed on the same plane.

[0020] Within the first cover unit 310, the first electrode 30 and the second electrode 40 both face the object to be heated OH, which is transported in the first direction by the transport unit 200, in the second direction. In this embodiment, the first direction is the -Y direction. The second direction is a direction intersecting the first direction, which is the -Z direction in this embodiment. The first electrode 30 and the second electrode 40 are disposed apart from the object to be heated OH. That is, in this embodiment, the first electrode 30 and the second electrode 40 are disposed above the sheet-like object to be heated OH such that the lower surface of each electrode faces the upper surface of the object to be heated OH. As a result, in this embodiment, the substrate 110 described above is disposed between the object to be heated OH and the first electrode 30 and the second electrode 40. In other embodiments, the second direction does not have to be perpendicular to the first direction.

[0021] In this embodiment, the substrate 110 is made of glass. The substrate 110 prevents a liquid such as ink applied to the object to be heated OH from adhering to the first electrode 30 and the second electrode 40, and prevents fluff from the object to be heated OH, if the object to be heated OH is a cloth, from adhering to the first electrode 30 and the second electrode 40. In other embodiments, the substrate 110 may be made of, for example, alumina.

[0022] An AC voltage is applied to the first electrode 30 and the second electrode 40 by the voltage application unit 80 shown in FIG. 1. In this embodiment, the voltage application unit 80 is configured as a high-frequency power supply including a high-frequency voltage generation circuit and outputs a high-frequency voltage. The voltage application unit 80 is configured, for example, with a crystal oscillator, a PLL (Phase Locked Loop) circuit, and a power amplifier. The voltage application unit 80 applies a high-frequency voltage to the first electrode 30 and the second electrode 40 by amplifying a high-frequency signal generated by the PLL circuit with the power amplifier and supplying the amplified signal to the electrode unit 20 via a coaxial cable or the like. One of the potentials applied to the first electrode 30 or the second electrode 40 may be a reference potential. The reference potential is a constant potential that serves as a reference for the high-frequency voltage, such as a ground potential. In this specification, the high-frequency voltage refers to an AC voltage having a frequency of 1 MHz or higher.

[0023] When an AC voltage is applied to the first electrode 30 and the second electrode 40, an electromagnetic field is generated from the first electrode 30 and the second electrode 40. The intensity of this electromagnetic field is very strong near the first electrode 30 and the second electrode 40 and very weak farther away. In this specification, the electromagnetic field generated near the first electrode 30 and the second electrode 40 by the application of an AC voltage is also referred to as the "near electromagnetic field." The "near" of the first electrode 30 and the second electrode 40 refers to a range where the distance from the first electrode 30 and the second electrode 40 is 1 / 2π or less of the wavelength of the generated electromagnetic field. A range farther away than the "near" is also referred to as the "far" range. In this specification, the electromagnetic field generated far from the first electrode 30 and the second electrode 40 by the application of an AC voltage is also referred to as the "far electromagnetic field." The far electromagnetic field corresponds to the electromagnetic field used in communication using a general communication antenna, etc.

[0024] As described above, the first electrode 30 and the second electrode 40 are arranged so that the shortest distance between them is equal to or less than one-tenth the wavelength of the electromagnetic field. This allows the electric field density of the electromagnetic field generated from the first electrode 30 and the second electrode 40 to be attenuated in the vicinity of the first electrode 30 and the second electrode 40. Therefore, by maintaining an appropriate distance between the object to be heated OH and the first electrode 30 and the second electrode 40, the object to be heated OH can be efficiently heated by the electric field generated in the vicinity of the first electrode 30 and the second electrode 40, while suppressing radiation of the far electromagnetic field from the first electrode 30 and the second electrode 40. In particular, in this embodiment, the second electrode 40 is arranged to surround the first electrode 30 when viewed along the Z direction, thereby further suppressing radiation of the far electromagnetic field from the first electrode 30 and the second electrode 40. Furthermore, if the second electrode 40 is arranged to surround the first electrode 30 when viewed along the Z direction, radiation of the far-field electromagnetic field from the first electrode 30 and the second electrode 40 can be suppressed even if the outer shapes of the first electrode 30 and the second electrode 40 when viewed along the Z direction are circular, rectangular, or polygonal other than rectangular.

[0025] The electromagnetic field generated by the electrode unit 20 has a wavelength λ0 corresponding to the frequency f0 of the AC voltage applied to the electrode unit 20 by the voltage application unit 80. Therefore, for example, if the object to be heated (OH) contains water, the dielectric loss tangent of water is maximized around 20 GHz. Therefore, applying a high-frequency voltage of 2.45 GHz or 5.8 GHz in the ISM band to the electrode unit 20 can more efficiently heat the object to be heated (OH) in the dielectric heating device 100. Furthermore, from the perspective of heating ink, good heating efficiency can be achieved even with a low frequency f0, such as 40.68 MHz, which is part of the ISM band. The reason for this is that at 40.68 MHz, the dielectric loss tangent of water in the ink is low, but Joule heat is easily generated by the electrical resistance of the pigment components in the ink.

[0026] In this embodiment, one end of the coil 50 is electrically connected in series to the first electrode 30 via an electric wire 75, and the other end is electrically connected in series to the voltage application unit 80. In this embodiment, the coil 50 is configured as a solenoid coil and is arranged so that its length direction is along the Z direction. The shape, length, cross-sectional area, number of turns, material, etc. of the coil 50 are selected, for example, so as to form a resonant circuit that resonates with the first electrode 30 and the second electrode 40 at a frequency f0, and to achieve impedance matching between the electrode unit 20 and the voltage application unit 80.

[0027] When the voltage application unit 80 applies an AC voltage to the electrode unit 20, a high voltage is generated at one end of the coil 50. This increases the strength of the electric field generated by the first electrode 30 and the second electrode 40. The coil 50 is preferably positioned so that the distance between the first electrode 30 and the coil 50 is as small as possible. If the distance between the first electrode 30 and the coil 50 is large, the high voltage generated at the coil 50 may generate an electric field between the coil 50 and the first electrode 30 or between the electric wire 75 and the second electrode 40 that does not contribute to heating the object OH. This may reduce the effectiveness of increasing the strength of the electric field generated by the first electrode 30 and the second electrode 40. By reducing the distance between the first electrode 30 and the coil 50, the generation of such an electric field that does not contribute to heating the object OH can be suppressed, thereby effectively increasing the strength of the electric field generated by the first electrode 30 and the second electrode 40. In other embodiments, the first electrode 30 may be formed in a meandering shape, so that the first electrode 30 functions similarly to the coil 50.

[0028] 3 is a diagram showing a cross section of the first electrode 30 taken along line III-III in FIG. 2. FIG. 4 is a diagram showing a cross section of the first electrode 30 taken along line IV-IV in FIG. 2. As shown in FIGS. 2 and 3, the first electrode 30 has an arc shape convex in the -Z direction when viewed along the X direction. Similarly, as shown in FIGS. 2 and 4, the first electrode 30 has an arc shape convex in the -Z direction when viewed along the Y direction. Therefore, the ends of the first electrode 30 in the longitudinal direction and the ends of the first electrode 30 in the lateral direction are located further in the +Z direction than the center of the first electrode 30.

[0029] The electrode unit 20 preferably has a shape that can suppress variations in electric field intensity within the range of the near electromagnetic field. For example, as described with reference to FIGS. 2 to 4, the first electrode 30 in this embodiment has an overall rounded shape with few sharp corners. This can suppress the concentration of the electric field at specific locations, such as the ends of the first electrode 30, compared to when the ends of the first electrode 30 have angular shapes. Furthermore, in this embodiment, because the first electrode 30 has a boat-like shape, the distance in the Z direction between the ends of the first electrode 30 and the object OH is longer than the distance in the Z direction between the center of the first electrode 30 and the object OH. Furthermore, the radius of curvature r of the short-side end of the first electrode 30 shown in FIG. 2 is smaller than the radius of curvature R of the long-side end of the first electrode 30 shown in FIG. 4. This can further suppress the concentration of the electric field at the ends of the first electrode 30, particularly the long-side end of the first electrode 30. In this way, by suppressing the variation in the electric field strength within the range of the near electromagnetic field, it is possible to suppress the variation in the electric field strength within the surface of the object to be heated OH, and to suppress uneven heating of the object to be heated OH.

[0030] 1 blocks radiant waves from the electrode unit 20 housed therein. The radiant waves from the electrode unit 20 refer to electromagnetic waves radiated from the electrode unit 20. These radiant waves include, for example, the far-field electromagnetic fields radiated from the first electrode 30 and the second electrode 40 described above, and the electromagnetic field generated by the coil 50.

[0031] "Blocking radiated waves" by the case 300 refers to the case 300 limiting the strength of the electromagnetic field radiated from the electrode unit 20 to an amount equal to or less than a predetermined standard value. This standard value is determined based on regulatory values ​​stipulated in national and regional guidelines regarding exposure restrictions to electromagnetic fields. Examples of such guidelines include Japan's Radio Wave Protection Guidelines and the guidelines established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). For example, the ICNIRP guidelines stipulate that the exposure limit for a magnetic field with a frequency of 40.68 MHz is 0.16 A / m for occupational exposure and 0.073 A / m for public exposure. Note that these exposure limit values ​​in the ICNIRP guidelines are all 6-minute average values.

[0032] FIG. 5 is a perspective view showing a schematic configuration of the first cover portion 310 of the case portion 300. When a radiant wave is emitted from the electrode unit 20, eddy currents are generated in the first cover portion 310, generating an electromagnetic field from the first cover portion 310 that weakens the radiant wave, thereby blocking the radiant wave. The magnitude of the eddy currents generated in the first cover portion 310 when a radiant wave is emitted is proportional to the half power of the electrical conductivity and the half power of the absolute magnetic permeability of the material constituting the first cover portion 310. Therefore, it is preferable that the material forming the first cover portion 310 has high electrical conductivity and absolute magnetic permeability. In this embodiment, the first cover portion 310 is formed of zinc, which has a relatively high electrical conductivity among metal materials.

[0033] The first cover part 310 in this embodiment has a rectangular parallelepiped outer shape. The first cover part 310 has a first insertion opening 312, a first outlet 314, and a plurality of first openings 316. The first insertion opening 312 is an opening for inserting the object to be heated OH into the first cover part 310. The first outlet 314 is an opening for sending the object to be heated OH inside the first cover part 310 to the outside of the first cover part 310. In this embodiment, the first insertion opening 312 is provided on a surface of the first cover part 310 on the +Y direction side, and the first outlet 314 is provided on a surface of the first cover part 310 on the -Y direction side. In other words, the first insertion opening 312 and the first outlet 314 are arranged opposite each other in the Y direction, with the electrode unit 20 sandwiched between them. The first insertion opening 312 and the first delivery opening 314 each have a rectangular opening shape with the X direction as the longitudinal direction and the Z direction as the lateral direction.

[0034] The first opening 316 is an opening different from the first insertion port 312 and the first delivery port 314. More specifically, in this embodiment, each surface of the first cover portion 310 is made of a wire mesh in which zinc wires are plain woven lengthwise and widthwise, and each opening defined by the wires corresponds to a first opening 316. As a result, in this embodiment, each surface of the first cover portion 310 has a plurality of first openings 316, each having a square opening shape, arranged lengthwise and widthwise in a direction along the surface. Note that FIG. 5 shows only the first openings 316 provided on the surface of the first cover portion 310 facing in the +X direction, and the first openings 316 provided on the other surfaces are omitted.

[0035] In this embodiment, the opening area of ​​one first opening 316 is smaller than the opening areas of the first insertion opening 312 and the first outlet 314. On the other hand, the sum of the opening areas of the first openings 316 is larger than the opening areas of the first insertion opening 312 and the first outlet 314. Furthermore, the opening diameter of the first opening 316 is smaller than the opening diameters of the first insertion opening 312 and the first outlet 314. In this specification, the opening diameter refers to the maximum length of the opening. For example, in this embodiment, the length of the diagonal of the first opening 316 corresponds to the opening diameter of the first opening 316. Note that in this embodiment, the length of each side of the first opening 316 is shorter than the length of any side of the first insertion opening 312 and the first outlet 314.

[0036] In other embodiments, each surface of the first cover portion 310 may be made of, for example, a wire mesh made of twilled wire, expanded metal, punched metal, or the like. Furthermore, the shape of the openings such as the first opening 316 does not have to be rectangular, and may be, for example, a circle, an oval, a diamond, or another polygonal shape. For example, if the opening shape of the first opening 316, etc. is circular, its diameter corresponds to the opening diameter of the first opening 316, etc. Furthermore, the first openings 316 do not have to be provided on all surfaces of the first cover portion 310, and the first openings 316 may be provided on only some surfaces.

[0037] The opening shape, opening area, opening diameter, number, position, etc. of the first openings 316 are preferably determined so that, when radiant waves are emitted from the electrode unit 20, eddy currents are generated in the first cover portion 310 to an extent that an electromagnetic field that weakens the radiant waves is generated. The opening diameter of the first openings 316 is preferably determined to be, for example, one-tenth of the wavelength λ0 or less in order to suppress leakage of the radiant waves to the outside of the first cover portion 310 through the first openings 316. Note that, as described above, in this embodiment, radiation of far-field electromagnetic fields from the first electrode 30 and the second electrode 40 can be suppressed, and therefore the opening shape, etc. of the first openings 316 can be determined taking this into consideration. In this case, for example, the opening area, opening diameter, and number of the first openings 316 can be increased within a range that suppresses leakage of the radiant waves to the outside of the first cover portion 310 through the first openings 316, thereby reducing the weight of the case portion 300.

[0038] As shown in FIG. 5, a first edge portion 317 is disposed around the first insertion opening 312. The first edge portion 317 is formed of an electrically insulating magnetic material and continuously surrounds the periphery of the first insertion opening 312. In this embodiment, a sheet-shaped Ni-Zn soft ferrite material is used as the first edge portion 317. The first edge portion 317 is fixed to the outer surface of the first cover portion 310 via an adhesive so as to surround the periphery of the first insertion opening 312 without interruption. Hereinafter, the first edge portion 317 may also be simply referred to as the edge portion. Note that the first edge portion 317 is omitted from FIG. 1 described above.

[0039] In this embodiment, the first edge 317 has a first portion 318 and a second portion 319. The second portion 319 is a portion of the first edge 317 that is provided at a position corresponding to the electrode unit 20 in the X direction and that has a width wider than the first portion 318. The "width" of the edge refers to the dimension in a direction perpendicular to the direction along the periphery of the first insertion opening 312. More specifically, the second portion 319 is provided so as to sandwich, in the Z direction, the portion of the first insertion opening 312 that is provided at a position corresponding to the electrode unit 20 in the X direction. The first portion 318 and the second portion 319 only need to be provided so as to be continuous with each other, and may be separate bodies or formed integrally.

[0040] Depending on the opening diameter, opening area, etc., the first insertion opening 312 may act as a pseudo slot antenna and radiate an electromagnetic field to the outside of the first cover part 310. More specifically, eddy currents generated in the first cover part 310 by the far electromagnetic field radiated from the electrode unit 20 generate an electric field in the first insertion opening 312, causing the first insertion opening 312 to act as a pseudo slot antenna. In this embodiment, as described above, the first edge part 317 formed of a magnetic material is arranged so as to surround the periphery of the first insertion opening 312, thereby suppressing the generation of eddy currents around the first insertion opening 312. Furthermore, because the first edge part 317 has electrical insulation, eddy currents caused by the far electromagnetic field radiated from the electrode unit 20 are less likely to be generated in the first edge part 317 itself. This prevents the first insertion opening 312 from acting as a pseudo slot antenna, and can suppress the electromagnetic field radiating from the first insertion opening 312 to the outside of the first cover part 310. Furthermore, in this embodiment, since the first edge part 317 has the second part 319, the generation of eddy currents is further suppressed in the part around the first insertion opening 312 where the distance to the electrode unit 20 is shorter, and the radiation of the electromagnetic field to the outside of the first cover part 310 can be more effectively suppressed.

[0041] Although not shown in the drawings, in this embodiment, the first edge portion 317 is also provided around the first outlet 314 so as to continuously surround the periphery of the first outlet 314. The effect of the first edge portion 317 provided around the first outlet 314 is similar to the effect of the first edge portion 317 provided around the first insertion opening 312 described above.

[0042] According to the first embodiment described above, the metal first cover part 310 surrounding the electrode unit 20 has multiple first openings 316 different from the first insertion opening 312 and the first outlet 314. This allows steam generated by heating the object OH inside the first cover part 310 to move out of the first cover part 310 through the first openings 316, thereby preventing steam from accumulating inside the first cover part 310. This prevents the object OH from being soiled by liquid generated by condensation of the accumulated steam and reduces the drying efficiency when the object OH is heated and dried. Furthermore, since the first cover part 310 has the first openings 316, the first cover part 310 is lighter than a first cover part 310 without the first openings 316. This allows the entire dielectric heating device 100 to be lighter.

[0043] Furthermore, according to this embodiment, first edge portion 317 is provided, which is made of an electrically insulating magnetic material and continuously surrounds at least one of first insertion opening 312 and first outlet 314. Therefore, first edge portion 317 can suppress the electromagnetic field radiating from first insertion opening 312 or first outlet 314 to the outside of first cover portion 310.

[0044] Furthermore, according to this embodiment, the first cover part 310 is made of zinc. Therefore, the weight of the first cover part 310 can be reduced compared to when the first cover part 310 is made of, for example, carbon steel or copper. Furthermore, the strength of the first cover part 310 can be increased compared to when the first cover part 310 is made of, for example, aluminum.

[0045] B. Second embodiment: 6 is a schematic diagram showing the general configuration of a dielectric heating device 100b in the second embodiment. Unlike the first embodiment, the case part 300b in this embodiment is composed of a first cover part 310 and a metal second cover part 320 that surrounds the first cover part 310. Portions of the configuration of the dielectric heating device 100b that are not particularly described are the same as those in the first embodiment.

[0046] 7 is a perspective view showing a schematic configuration of the second cover part 320. In this embodiment, the second cover part 320 is made of zinc and has a rectangular parallelepiped shape. The external dimensions of the second cover part 320 in the X, Y, and Z directions are larger than the external dimensions of the first cover part 310 in the X, Y, and Z directions.

[0047] As shown in FIGS. 6 and 7 , the second cover part 320 has a second insertion opening 322, a second outlet 324, and a plurality of second openings 326. Note that the second opening 326 is omitted in FIG. 6 . The second insertion opening 322 is an opening for inserting the object to be heated OH into the second cover part 320. The second outlet 324 is an opening for outletting the object to be heated OH inside the second cover part 320 to the outside of the second cover part 320. As shown in FIG. 6 , the second insertion opening 322 is provided on the surface of the second cover part 320 on the +Y direction side, and the second outlet 324 is provided on the surface of the second cover part 320 on the −Y direction side. More specifically, the second insertion opening 322 is provided at a position corresponding to the first insertion opening 312, and the second outlet 324 is provided at a position corresponding to the first outlet 314. In this embodiment, the second insertion opening 322 and the second delivery opening 324 have the same opening shape and dimensions as the first insertion opening 312 and the second delivery opening 324, respectively.

[0048] In this embodiment, the object to be heated OH is first inserted into the second cover part 320 through the second insertion opening 322. As a result, the object to be heated OH is inserted into the case part 300b. Next, the object to be heated OH is inserted into the first cover part 310 through the first insertion opening 312. Then, the object to be heated OH is heated by the electrode unit 20 inside the first cover part 310, and then sent out of the first cover part 310 through the first outlet 314. Next, the object to be heated OH is sent out of the second cover part 320 through the second outlet 324. As a result, the object to be heated OH is sent out of the case part 300b.

[0049] The second openings 326 shown in FIG. 7 are different from the second insertion openings 322 and the second delivery openings 324. More specifically, each surface of the second cover portion 320, like each surface of the first cover portion 310, is made of a wire mesh in which zinc wires are plain woven lengthwise and widthwise, and each opening defined by the wires corresponds to a second opening 326. In this embodiment, the second openings 326 have the same opening shape and dimensions as the first openings 316. As described above, the outer dimensions of the second cover portion 320 are larger than the outer dimensions of the first cover portion 310, and therefore the sum of the opening areas of the second openings 326 is larger than the sum of the opening areas of the first openings 316. Note that FIG. 7 only shows the second openings 326 provided on the surface of the second cover portion 320 facing the +X direction, and the second openings 326 provided on the other surfaces are omitted.

[0050] 7, a second edge portion 327 is disposed around the second insertion opening 322. The second edge portion 327 is formed of an electrically insulating magnetic material and continuously surrounds the periphery of the second insertion opening 322. In this embodiment, the second edge portion 327 is made of a sheet-like Ni-Zn soft ferrite material, similar to the first edge portion 317. The second edge portion 327 is fixed to the outer surface of the second cover portion 320 via an adhesive so as to surround the periphery of the second insertion opening 322 without interruption.

[0051] In this embodiment, the second edge portion 327 has a third portion 328 and a fourth portion 329. The fourth portion 329 is a portion of the second edge portion 327 that is provided at a position corresponding to the electrode unit 20 in the X direction and has a width wider than the third portion 328. The configuration of the third portion 328 is similar to the configuration of the first portion 318 of the first edge portion 317, and the configuration of the fourth portion 329 is similar to the configuration of the second portion 319 of the first edge portion 317. The second edge portion 327 suppresses radiation of the electromagnetic field out of the second cover portion 320, in the same way that the first edge portion 317 suppresses radiation of the electromagnetic field out of the first cover portion 310. Note that, as shown in FIG. 6 , the second edge portion 327 is also provided around the second outlet 324 so as to continuously surround the periphery of the second outlet 324.

[0052] According to the second embodiment described above, the second cover part 320 is made of metal and surrounds the first cover part 310. The second cover part 320 has a plurality of second openings 326 that are different from the second insertion opening 322 and the second outlet 324. This allows the radiant waves from the electrode unit 20 to be suppressed not only by the first cover part 310 but also by the second cover part 320, so that the entire case part 300 can block higher-intensity radiant waves compared to a case without the second cover part 320. Therefore, for example, a higher voltage can be applied to the electrode unit 20, and the heating efficiency of the object to be heated OH can be further improved.

[0053] Furthermore, according to the present embodiment, the sum of the opening areas of the second openings 326 is greater than the sum of the opening areas of the first openings 316. This makes it possible to further suppress steam from accumulating inside the second cover part 320 and reduce the weight of the second cover part 320, compared to when the sum of the opening areas of the second openings 326 is equal to or less than the sum of the opening areas of the first openings 316.

[0054] In other embodiments, the second insertion opening 322 and the second outlet 324 do not have to be provided at positions corresponding to the first insertion opening 312 and the first outlet 314. For example, in a case where the object to be heated OH is inserted into the first cover part 310 in the -Y direction via the second insertion opening 322 and the first insertion opening 312, is delivered to the outside of the first cover part 310 via the first outlet 314, and then is turned around in the +Y direction within the second cover part 320 to be delivered to the outside of the second cover part 320, the second outlet 324 may be provided on the surface of the second cover part 320 facing the first insertion opening 312. That is, in this case, the second insertion opening 322 and the second outlet 324 may both be provided on the surface of the second cover part 320 on the +Y direction side.

[0055] C. Third embodiment: Fig. 8 is a perspective view showing the schematic configuration of a dielectric heating device 100c in the third embodiment. Unlike the first embodiment, the dielectric heating device 100c includes multiple electrode units 20. Portions of the configuration of the dielectric heating device 100c that are not specifically described are the same as those in the first embodiment. Note that in Fig. 8, the first edge portion 317 is omitted, as in Fig. 1 described in the first embodiment.

[0056] The electrode units 20 are arranged side by side in a third direction that intersects the first direction and is perpendicular to the second direction. The third direction includes both a direction on one side along the same axis and a direction opposite to the same axis, and in this embodiment, is a direction along the X-axis.

[0057] The dielectric heating device 100c in this embodiment has two unit rows UC. Each unit row UC is composed of four electrode units 20 arranged side by side in the X direction. In other words, the dielectric heating device 100b has a total of eight electrode units 20. The unit rows UC are arranged side by side in the Y direction.

[0058] 8, in this embodiment, eight substrates 110 are provided corresponding to the electrode units 20. In other embodiments, the substrate 110 may be provided in common to a plurality of electrode units 20, or, for example, only one substrate 110 may be provided for all the electrode units 20.

[0059] In this embodiment, AC voltages with phases reversed by 180° are applied to electrode units 20 adjacent to each other in the X direction and the Y direction. This allows radiant waves from adjacent electrode units 20 to be weakened, so that, for example, even if a high voltage is applied to each electrode unit 20, the radiant waves can be blocked by the case 300, thereby further improving the heating efficiency of the object to be heated OH. Note that, in another embodiment, for example, AC voltages with reversed phases may be applied to electrode units 20 adjacent to each other in the X direction, and AC voltages of the same phase may be applied to electrode units 20 adjacent to each other in the Y direction. Even in this case, radiant waves from electrode units 20 to which AC voltages with reversed phases are applied can be weakened.

[0060] According to the third embodiment described above, the heater includes multiple electrode units 20, which are arranged side by side in the X direction. Therefore, even when heating an object OH that is larger in size in the X direction, the object OH can be efficiently heated by the multiple electrode units 20 while being transported in the -Y direction. Furthermore, even if the voltage applied to each electrode unit 20 is reduced, it is easy to obtain sufficient output from the multiple electrode units 20 as a whole to heat the object OH. Therefore, by reducing the voltage applied to each electrode unit 20, Joule heat generated by the parasitic resistance of the electrode units 20 can be suppressed, and electric field concentration when an AC voltage is applied to the electrode units 20 can be suppressed.

[0061] In other embodiments, the number of unit rows UC does not have to be two, and may be, for example, one, or three or more. The number of electrode units 20 included in one unit row UC does not have to be four, and may be, for example, two, three, or five or more. The number of electrode units 20 included in each unit row UC may differ from one another.

[0062] D. Fourth embodiment: Fig. 9 is a schematic diagram of a dielectric heating device 100d according to the fourth embodiment. Unlike the first embodiment, the dielectric heating device 100d includes an airflow generating unit 120 that generates an airflow within the first cover part 310. Portions of the configuration of the dielectric heating device 100d that are not specifically described are the same as those of the first embodiment. Note that the first opening 316 provided in the first cover part 310 is omitted from Fig. 9.

[0063] In this embodiment, the airflow generating unit 120 is configured as a blower fan. The airflow generating unit 120 is disposed in the +Y direction of the first cover unit 310 and blows air toward the first cover unit 310. As a result, the gas sent from the airflow generating unit 120 is supplied into the first cover unit 310 through the first openings 316 shown in FIG. 5 , generating an airflow within the first cover unit 310. In particular, in this embodiment, the first openings 316 are provided on each side of the first cover unit 310, so that the airflow generated within the first cover unit 310 can more efficiently ventilate the inside and outside of the first cover unit 310. In other embodiments, the airflow generating unit 120 may be configured as a suction fan, duct, or the like for sucking in gas within the first cover unit 310 and discharging it to the outside. Furthermore, the airflow generating unit 120 does not have to be disposed in the +Y direction of the first cover unit 310 and may be disposed, for example, above the first cover unit 310.

[0064] According to the fourth embodiment described above, the dielectric heating device 100d includes the airflow generating unit 120 that generates an airflow inside the first cover part 310. Therefore, by generating an airflow inside the first cover part 310 using the airflow generating unit 120, it is possible to efficiently ventilate the inside and outside of the first cover part 310. Therefore, it is possible to further prevent steam generated by heating the object to be heated OH from remaining inside the first cover part 310.

[0065] E. Fifth embodiment: FIG. 10 is a perspective view showing the general configuration of a dielectric heating device 100e in the fifth embodiment. FIG. 11 is a schematic diagram showing the general configuration of a dielectric heating device 100e in the fifth embodiment. Unlike the first embodiment, the dielectric heating device 100e includes a moving section 130. Furthermore, the case section 300c in this embodiment is composed of a first cover section 310 and a third cover section 330. Portions of the configuration of the dielectric heating device 100e that are not particularly described are the same as those in the first embodiment. Note that the first edge section 317 is omitted in FIG. 10, as in FIG. 1 described in the first embodiment. Furthermore, the first opening section 316 is omitted in FIG. 11.

[0066] The third cover part 330 is disposed within the first cover part 310. The third cover part 330 is a metal member that covers the electrode unit 20 and faces the object to be heated OH, which is transported in the -Y direction, in the -Z direction. The third cover part 330 has a third opening 335 that opens in the -Z direction toward the object to be heated OH. The third opening 335 surrounds at least the first electrode 30 and the second electrode 40 when viewed along the Z direction. In this embodiment, the third cover part 330 has an overall rectangular parallelepiped outer shape, and the third opening 335 is formed as an opening with a rectangular opening shape that extends across the entire lower surface of the third cover part 330. Like the first cover part 310, the third cover part 330 in this embodiment is made of zinc. The outer dimensions of the third cover part 330 in the X, Y, and Z directions are smaller than the outer dimensions of the first cover part 310 in the X, Y, and Z directions. In Figure 11, the third cover part 330 and the substrate 110 are shown separated to make it easier to understand the configuration, but in reality, the lower end of the third cover part 330 and the upper surface of the substrate 110 are in contact with each other.

[0067] FIG. 12 is a perspective view showing a schematic configuration of the third cover portion 330. As shown in FIG. 12, the third cover portion 330 has a plurality of fourth openings 336. The fourth openings 336 are openings different from the third openings 335. More specifically, each surface of the third cover portion 330 except for the bottom surface is formed of a wire mesh in which zinc wires are woven vertically and horizontally, similar to each surface of the first cover portion 310. Each opening defined by the wires corresponds to a fourth opening 336. In this embodiment, the fourth opening 336 has the same dimensions and shape as the first opening 316. That is, in this embodiment, the opening area of ​​the fourth opening 336 is smaller than the opening areas of the first insertion opening 312 and the first outlet 314. Furthermore, the opening diameter of the fourth opening 336 is smaller than the opening diameters of the first insertion opening 312 and the first outlet 314. 12 shows only the fourth openings 336 provided on the surface of the second cover part 320 on the +X direction side, and omits the fourth openings 336 provided on other surfaces. Also, the fourth openings 336 are omitted from the above-mentioned FIGS. 10 and 11.

[0068] The moving unit 130 shown in Figures 10 and 11 is configured to be able to move the electrode unit 20 back and forth in a fourth direction. The fourth direction is a direction that intersects with the first direction and is perpendicular to the second direction. The fourth direction includes both a direction on one side along the same axis and a direction opposite to the same axis, and in this embodiment, is a direction along the X axis. The above-mentioned third cover part 330 is configured to be able to move in the X direction together with the electrode unit 20 by the moving unit 130.

[0069] The moving unit 130 is composed of, for example, a support unit that supports the electrode unit 20 and the third cover unit 330, and a drive unit that moves the support unit along the X direction. The support unit may directly support both the electrode unit 20 and the third cover unit 330, or, for example, in a case where the third cover unit 330 is fixed to the electrode unit 20, the support unit may directly support only the third cover unit 330. The drive unit may be composed of, for example, a belt mechanism having an endless belt and pulleys, or a ball screw mechanism having a ball screw and a motor.

[0070] According to the fifth embodiment described above, the dielectric heating device 100e includes a moving unit 130 configured to be able to move the electrode unit 20 back and forth in the X direction. Therefore, even when heating an object OH that is larger in size in the X direction, the object OH can be efficiently heated by the electrode unit 20 that moves back and forth in the X direction while transporting the object OH in the -Y direction. Therefore, for example, an object OH that is larger in size in the X direction can be efficiently heated without providing multiple electrode units 20.

[0071] Furthermore, in this embodiment, the case 300 includes a metal third cover part 330 that is disposed within the first cover part 310, covers the electrode unit 20, and faces the object to be heated OH transported in the -Y direction in the -Z direction. The third cover part 330 is configured to be able to move back and forth in the X direction together with the electrode unit 20, and has a third opening 335 that opens in the -Z direction toward the object to be heated OH and surrounds the first electrode 30 and the second electrode 40 when viewed along the Z direction, and a plurality of fourth openings 336 different from the third opening 335. This allows the radiant waves from the electrode unit 20 to be suppressed not only by the first cover part 310 but also by the third cover part 330, so that the entire case 300 can block more intense radiant waves than when the third cover part 330 is not provided. Moreover, because the third cover part 330 is configured to be able to move back and forth in the X direction together with the electrode unit 20, the dimension of the third cover part 330 in the X direction can be made large enough to accommodate the electrode unit 20, thereby achieving weight and cost reductions for the dielectric heating device 100e compared to, for example, a case in which the electrode unit 20 is accommodated in a metal cover having dimensions corresponding to the range of movement of the electrode unit 20. Furthermore, because the third cover part 330 is provided with a plurality of fourth openings 336, it is possible to prevent steam generated by heating the object to be heated OH from accumulating within the third cover part 330.

[0072] F. Sixth embodiment: Fig. 13 is a perspective view showing the general configuration of a dielectric heating device 100f in the sixth embodiment. Fig. 14 is a schematic diagram showing the general configuration of a dielectric heating device 100f in the sixth embodiment. Unlike the first embodiment, the dielectric heating device 100f does not include a case portion 300, i.e., a first cover portion 310, but includes a moving portion 130b, a fourth cover portion 340, and an opposing portion 150. Portions of the configuration of the dielectric heating device 100f that are not particularly described are the same as those in the first embodiment.

[0073] The fourth cover part 340 is a metal member that covers the electrode unit 20 and faces the object to be heated OH, which is transported in the -Y direction, in the -Z direction. The fourth cover part 340 has a fifth opening 345 that opens in the -Z direction toward the object to be heated OH. The fifth opening 345 surrounds at least the first electrode 30 and the second electrode 40 when viewed along the Z direction. In this embodiment, the fourth cover part 340 has an overall rectangular parallelepiped outer shape. In this embodiment, the fourth cover part 340 has an overall rectangular parallelepiped outer shape, and the fifth opening 345 is formed as an opening with a rectangular opening shape that extends across the entire lower surface of the fourth cover part 340. The fourth cover part 340 may be made of zinc, for example, similar to the first cover part 310 described in the first embodiment, or may be made of carbon steel, aluminum, stainless steel, copper, an alloy of various metals, or the like. Furthermore, all or part of each surface of the fourth cover portion 340 may be made of a wire mesh or the like, similar to the first cover portion 310, and may have a plurality of openings.

[0074] The moving unit 130b is configured to be able to move the electrode unit 20 back and forth in a fifth direction. The fifth direction is a direction that intersects with the first direction and is perpendicular to the second direction. The fifth direction includes both a direction on one side along the same axis and a direction opposite to the same axis, and in this embodiment, is a direction along the X-axis. The fourth cover part 340 described above is configured to be able to move in the X direction together with the electrode unit 20 by the moving unit 130b. The moving unit 130b is configured by a support part that supports the electrode unit 20 and the fourth cover part 340, and a drive part that moves the support part along the X direction. The support part and the drive part are configured similarly to the support part and the drive part of the moving unit 130 described in the fifth embodiment, for example.

[0075] The facing portion 150 is a metal member that faces the first electrode 30 and the second electrode 40 in the Z direction, sandwiching the object to be heated OH therebetween. In this embodiment, the facing portion 150 has a recess 151 that opens in the +Z direction, which is the opposite direction to the -Z direction. As shown in FIG. 14 , the lower end 341 of the fourth cover portion 340 described above is disposed within the opening of the recess 151. It can also be said that the lower end 341 of the fourth cover portion 340 is located below the upper end 152 of the inner wall portion of the opening of the recess 151. In this embodiment, the opening of the recess 151 has a dimension in the X direction that is larger than the movement range of the fourth cover portion 340. This allows the moving portion 130b to move the fourth cover portion 340 and the electrode unit 20 back and forth in the X direction while keeping the lower end 341 of the fourth cover portion 340 disposed within the recess 151.

[0076] According to the sixth embodiment described above, the dielectric heating device 100f includes a moving unit 130b configured to reciprocate the electrode unit 20 in the X direction, a metal fourth cover unit 340 that faces the object OH in the -Z direction, covers the electrode unit 20, and faces the object OH being transported in the -Y direction in the -Z direction, and a metal opposing unit 150 that faces the first electrode 30 and the second electrode 40 in the Z direction, sandwiching the object OH being transported in the -Y direction. The fourth cover unit 340 is configured to reciprocate in the X direction together with the electrode unit 20, and has a fifth opening 345 that opens in the -Z direction toward the object OH and surrounds the first electrode 30 and the second electrode 40 when viewed along the Z direction. This allows the electrode unit 20 to heat the object OH while blocking radiant waves using the fourth cover unit 340 and the opposing unit 150, even without providing a casing for heating the object OH while preventing leakage of radiant waves from the electrode unit 20. This prevents the retention of steam generated by heating the object OH, thereby preventing the liquid generated by condensation of the retained steam from contaminating the object OH and reducing the drying efficiency when the object OH is heated and dried.

[0077] Furthermore, in this embodiment, the facing part 150 has a recess 151 that opens in the +Z direction, and the lower end 341 of the fourth cover part 340 is disposed within the opening of the recess 151. This allows the fourth cover part 340 and the facing part 150 to block more intense radiant waves than when the lower end 341 of the fourth cover part 340 is disposed outside the opening of the recess 151. Therefore, for example, a higher voltage can be applied to the electrode unit 20, and the heating efficiency of the object to be heated OH can be further improved.

[0078] G. Seventh embodiment: Fig. 15 is a schematic diagram of a dielectric heating device 100g in the seventh embodiment. Fig. 16 is a perspective view showing the general configuration of a fourth cover part 340b in the seventh embodiment. Unlike the sixth embodiment, the dielectric heating device 100g in this embodiment has a fourth edge part 347 that continuously surrounds the periphery of a fifth opening 345 of the fourth cover part 340b. Portions of the configuration of the dielectric heating device 100g in this embodiment that are not particularly described are the same as those in the sixth embodiment.

[0079] The fourth edge portion 347 is formed of an electrically insulating magnetic material. In this embodiment, the fourth edge portion 347 is made of a sheet-like Ni-Zn soft ferrite material, similar to the first edge portion 317. The fourth edge portion 347 is fixed to the outer surface of the lower end 341 of the fourth cover portion 340b via an adhesive so as to surround the periphery of the fifth opening 345 without interruption. In other embodiments, the fourth edge portion 347 may be fixed to, for example, the inner surface of the lower end 341, or to both the outer and inner surfaces.

[0080] According to the seventh embodiment described above, a fourth edge portion 347 is disposed around the fifth opening 345 of the fourth cover portion 340b, and the fourth edge portion 347 is formed of a magnetic material having lower electrical conductivity than the metal forming the fourth cover portion 340b. This allows the fourth edge portion 347 to suppress the electromagnetic field radiating from the fifth opening 345 to the outside of the fourth cover portion 340b, just as the first edge portion 317 described in the first embodiment suppresses the electromagnetic field radiating from the first insertion opening 312 to the outside of the first cover portion 310.

[0081] H. Eighth embodiment: 17 is a diagram showing a schematic configuration of a printing system 600 according to an eighth embodiment. The printing system 600 includes the dielectric heating device 100 described in the first embodiment and a liquid ejection device 610.

[0082] The liquid ejection device 610 of this embodiment is configured as an inkjet printer and includes a liquid ejection unit 620 that ejects liquid onto a print medium, a medium transport unit 630 that transports the print medium, and an ejection control unit 640 that controls the liquid ejection unit 620 and the medium transport unit 630. The liquid ejection unit 620 is configured, for example, by a piezoelectric or thermal liquid ejection head. The medium transport unit 630 is configured, for example, by rollers, similar to the transport unit 200. The ejection control unit 640 is configured, for example, by a computer, similar to the control unit 500 of the dielectric heating device 100. The ejection control unit 640 controls the liquid ejection unit 620 and the medium transport unit 630 to eject and adhere liquid onto the print medium while transporting the print medium.

[0083] As described in the first embodiment, the dielectric heating device 100 heats the print medium to which the liquid discharged by the liquid discharger 620 has adhered as the object to be heated OH. That is, the transport unit 200 transports the print medium to which the liquid has adhered as the object to be heated OH. As shown in FIG. 17 , the object to be heated OH may be continuously transported from the liquid discharger 610 to the dielectric heating device 100. In this case, for example, the transport unit 200 of the dielectric heating device 100 may function as the medium transport unit 630. Furthermore, the object to be heated OH does not have to be continuously transported from the liquid discharger 610 to the dielectric heating device 100. For example, the print medium to which the liquid discharged by the liquid discharger 610 has adhered may be wound into a roll, and then the wound print medium may be moved to the dielectric heating device 100 by a robot or the like. In this case, the rolled print medium is unwound while being transported as the object to be heated OH by the transport unit 200, thereby allowing the object to be heated in the dielectric heating device 100.

[0084] The eighth embodiment described above also makes it possible to prevent steam generated by heating the object to be heated OH from accumulating inside the case part 300. Note that in other embodiments, the dielectric heating device 100 provided in the printing system 600 may have the configurations described in the second to seventh embodiments.

[0085] I. Other Embodiments: (I-1) In the above embodiment, first edge portion 317 is arranged around at least one of first insertion opening 312 and first outlet 314. In contrast, first edge portion 317 does not have to be arranged around first insertion opening 312 or first outlet 314. Similarly, second edge portion 327 does not have to be arranged around second insertion opening 322 or second outlet 324.

[0086] (I-2) In the above embodiment, the sum of the opening areas of the second openings 326 is greater than the sum of the opening areas of the first openings 316. In contrast, the sum of the opening areas of the second openings 326 may be equal to or less than the sum of the opening areas of the first openings 316.

[0087] (I-3) In the above embodiment, the first cover portion 310 is made of zinc. However, the first cover portion 310 may be made of a metal other than zinc, such as carbon steel, stainless steel, aluminum, copper, or an alloy of various metals. Similarly, the second cover portion 320 and the third cover portion 330 may be made of a metal other than zinc.

[0088] (I-4) In the above embodiment, the second electrode 40 is arranged to surround the first electrode 30 when viewed along the Z direction. In contrast, for example, the first electrode 30 and the second electrode 40 may be arranged to be adjacent to each other when viewed along the Z direction. In this case, for example, when the frequency f0 of the high-frequency voltage applied to the electrode unit 20 is 2.45 GHz, the areas of the first electrode 30 and the second electrode 40 when viewed along the Z direction are 0.01 cm. 2 More than 100.0cm 2 It is preferable that it is less than 0.1 cm. 2 More than 10.0cm 2 It is more preferable that it is less than 0.5cm. 2 More than 2.0cm 2 It is more preferable that it is less than 0.5 cm. 2 More than 1.0cm 2 It is even more preferable that the area is less than 1 / 2 mm. This allows for suppression of radiation of the far electromagnetic field from the first electrode 30 and the second electrode 40. Note that when the frequency f0 is lower than 2.45 GHz, radiation of the far electromagnetic field from the first electrode 30 and the second electrode 40 can be effectively suppressed even if the areas are smaller than the above. In this case, the first electrode 30 and the second electrode 40 may have any shape, such as a circle, an oval, a rectangle, or a polygon. Furthermore, when viewed along the Z direction, the areas of the first electrode 30 and the second electrode 40 may be the same or different. It is preferable that the first electrode 30 and the second electrode 40 are arranged so as not to overlap each other when viewed along the Z direction.

[0089] (I-5) In the above embodiment, a high-frequency voltage is applied to the electrode unit 20. In contrast, the frequency of the AC voltage applied to the electrode unit 20 does not have to be high frequency as long as it is a frequency that can heat the object to be heated OH. In this case, the frequency of the AC voltage is preferably, for example, not less than 100 kHz and less than 1 MHz.

[0090] (I-6) In the above embodiment, the case 300 may have a resin box portion, and for example, the first cover 310 may be fixed to the inner wall surface of the box portion. In this case, one or more openings are provided in the box portion at positions corresponding to at least one of the first openings 316 of the first cover 310. For example, a pipe or duct for blowing or suctioning air into or from the case 300 may be connected to this opening. The first cover 310 may also be embedded in the wall surface of the box portion, and in this case, the box portion also has openings similar to those described above. Furthermore, when the case 300b has the second cover 320 described in the second embodiment, the second cover 320 may be fixed to the inner wall surface of the box portion, or the second cover 320 may be embedded in the wall surface of the box portion. Since the first cover part 310 and the second cover part 320 are provided with a plurality of first openings 316 and second openings 326, the degree of freedom in arranging the openings provided in the box part can be increased compared to when only a single opening is provided in the first cover part 310 and the second cover part 320.

[0091] J. Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following forms. The technical features in the above embodiments corresponding to the technical features in each form described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0092] (1) According to a first aspect of the present disclosure, there is provided a dielectric heating device including: a transport unit for transporting an object to be heated; an electrode unit having first and second electrodes to which an AC voltage is applied, the electrode unit facing the object to be heated transported in a first direction in a second direction intersecting the first direction; and a metal first cover unit surrounding the electrode unit. The first cover unit has a first insertion opening for inserting the object to be heated into the first cover unit, a first delivery opening for delivering the object to be heated out of the first cover unit, and a plurality of first openings different from the first insertion opening and the first delivery opening. According to this configuration, steam generated by heating the object to be heated in the first cover part can move outside the first cover part through the first opening, thereby preventing steam from accumulating inside the first cover part. This prevents the object to be heated from being soiled by liquid generated by condensation of the accumulated steam, and prevents a decrease in drying efficiency when the object to be heated is heated and dried.

[0093] (2) In the above embodiment, the cover may further include an edge portion made of an electrically insulating magnetic material and continuously surrounding at least one of the first insertion opening and the first transmission opening. According to this embodiment, the edge portion can suppress electromagnetic fields radiating from the first insertion opening or the first transmission opening to the outside of the first cover.

[0094] (3) In the above embodiment, a metal second cover portion may be provided surrounding the first cover portion, the second cover portion having a second insertion opening for inserting the object to be heated into the second cover portion, a second outlet opening for outletting the object to be heated to the outside of the second cover portion, and a plurality of second openings different from the second insertion opening and the second outlet opening. According to this embodiment, the radiant waves from the electrode unit can be suppressed not only by the first cover portion but also by the second cover portion, so that a higher intensity of radiant waves can be blocked overall compared to a case where the second cover portion is not provided. Therefore, for example, a higher voltage can be applied to the first electrode and the second electrode of the electrode unit, thereby further improving the heating efficiency of the object to be heated.

[0095] (4) In the above embodiment, the sum of the opening areas of the second openings may be greater than the sum of the opening areas of the first openings. According to this embodiment, compared to when the sum of the opening areas of the second openings is equal to or less than the sum of the opening areas of the first openings, it is possible to further suppress steam from accumulating within the second cover portion and reduce the weight of the second cover portion.

[0096] (5) In the above embodiment, a plurality of the electrode units may be provided, and the plurality of electrode units may be arranged side by side in a third direction that intersects with the first direction and is perpendicular to the second direction. According to this embodiment, even when an object to be heated has a larger dimension in the third direction, the object to be heated can be efficiently heated by the plurality of electrode units while being transported in the first direction.

[0097] (6) In the above embodiment, a moving unit may be provided that is configured to reciprocate the electrode unit in a fourth direction that intersects with the first direction and is perpendicular to the second direction. According to this embodiment, even when an object to be heated has a larger dimension in the fourth direction, the object can be efficiently heated by the electrode unit that reciprocates in the fourth direction while transporting the object in the first direction. Therefore, for example, an object to be heated having a larger dimension in the fourth direction can be efficiently heated without providing multiple electrode units.

[0098] (7) The above embodiment may further include a third metal cover disposed within the first cover, covering the electrode unit, and facing the object to be heated in the second direction. The third cover may be configured to reciprocate in the fourth direction together with the electrode unit, open in the second direction toward the object to be heated, and have a third opening that surrounds the first electrode and the second electrode when viewed along the second direction, and multiple fourth openings different from the third openings. According to this embodiment, radiant waves from the electrode unit can be suppressed not only by the first cover but also by the third cover, thereby blocking higher-intensity radiant waves overall compared to a configuration without a third cover. Furthermore, because the third cover is configured to reciprocate in the fourth direction together with the electrode unit, the dimension of the third cover in the fourth direction can be set to be sufficient to accommodate the electrode unit, thereby achieving weight and cost reductions for the dielectric heating device. Furthermore, the provision of multiple fourth openings in the third cover prevents steam generated by heating the object from accumulating within the third cover.

[0099] (8) In the above embodiment, the first cover portion may be made of zinc. According to this embodiment, the first cover portion can be made lighter than when the first cover portion is made of, for example, carbon steel or copper. Furthermore, the strength of the first cover portion can be increased compared to when the first cover portion is made of, for example, aluminum.

[0100] (9) In the above embodiment, an airflow generating unit that generates an airflow inside the first cover unit may be provided. According to this embodiment, the airflow generating unit generates an airflow inside the first cover unit, thereby efficiently ventilating the inside and outside of the first cover unit. This further prevents steam generated by heating the object to be heated from accumulating inside the first cover unit.

[0101] (10) According to a second aspect of the present disclosure, there is provided a dielectric heating device comprising: a transport unit that transports an object to be heated; an electrode unit that faces the object to be heated transported in a first direction in a second direction intersecting the first direction and has first and second electrodes to which an AC voltage is applied; a transport unit that is configured to reciprocate the electrode unit in a fifth direction intersecting the first direction and orthogonal to the second direction; a metal fourth cover unit that faces the object to be heated transported in the first direction in the second direction and covers the electrode unit; and a metal opposing unit that faces the first and second electrodes across the object to be heated in a direction along the second direction. The fourth cover unit is configured to reciprocate in the fifth direction together with the electrode unit, and has a fifth opening that opens in the second direction toward the object to be heated and surrounds the first and second electrodes when viewed along the second direction. According to this configuration, even without providing a casing for preventing leakage of radiant waves from the electrode unit while heating the object, the object can be heated by the electrode unit while blocking radiant waves with the fourth cover part and the opposing part. This prevents steam generated by heating the object from accumulating. This prevents the object from being soiled by liquid generated by condensation of the accumulating steam, and prevents a decrease in drying efficiency when heating and drying the object.

[0102] (11) According to a third aspect of the present disclosure, there is provided a printing system including the dielectric heating device of the above aspect and a liquid ejection unit that ejects liquid onto a printing medium, and the transport unit transports the printing medium with the liquid attached thereto as the object to be heated. [Explanation of symbols]

[0103] 20...electrode unit, 30...first electrode, 40...second electrode, 50...coil, 60...support member, 70...internal conductor, 75...electric wire, 80...voltage application section, 100, 100b, 100c, 100d, 100e, 100f, 100g...dielectric heating device, 110...substrate, 120...airflow generation section, 130, 130b...moving section, 150...opposing section, 151...recess, 152...upper end, 200...conveying section, 205...conveying roller, 300, 300b, 300c...case section, 310...first cover section, 312...first insertion port, 314...first outlet, 316...second 1. Opening, 317...first edge, 318...first portion, 319...second portion, 320...second cover portion, 322...second insertion port, 324...second outlet, 326...second opening, 327...second edge, 328...third portion, 329...fourth portion, 330...third cover portion, 335...third opening, 336...fourth opening, 340, 340b...fourth cover portion, 341...bottom end, 345...fifth opening, 347...fourth edge, 500...control portion, 600...printing system, 610...liquid ejection device, 620...liquid ejection portion, 630...medium transport portion, 640...ejection control portion

Claims

1. a conveying unit that conveys the object to be heated; an electrode unit having a first electrode and a second electrode, the electrode unit facing the object to be heated in a second direction intersecting the first direction and to which an AC voltage is applied; a first cover portion made of metal that surrounds the electrode unit, The first cover portion is a first insertion opening for inserting the object to be heated into the first cover portion; a first outlet for delivering the object to be heated to the outside of the first cover portion; a plurality of first openings different from the first insertion opening and the first delivery opening, An induction heating device, wherein the opening area of ​​each of the plurality of first openings is smaller than both the opening area of ​​the first insertion opening and the opening area of ​​the first delivery opening, and the sum of the opening areas of the plurality of first openings is larger than both the opening area of ​​the first insertion opening and the opening area of ​​the first delivery opening.

2. A dielectric heating device, a conveying unit that conveys the object to be heated; an electrode unit having a first electrode and a second electrode, the electrode unit facing the object to be heated in a second direction intersecting the first direction and to which an AC voltage is applied; a first cover portion made of metal that surrounds the electrode unit, The first cover portion is a first insertion opening for inserting the object to be heated into the first cover portion; a first outlet for delivering the object to be heated to the outside of the first cover portion; a plurality of first openings different from the first insertion opening and the first delivery opening, The dielectric heating device further includes an edge portion formed of an electrically insulating magnetic material and continuously surrounding at least one of the first insertion port and the first delivery port.

3. A dielectric heating device, a conveying unit that conveys the object to be heated; an electrode unit having a first electrode and a second electrode, the electrode unit facing the object to be heated in a second direction intersecting the first direction and to which an AC voltage is applied; a first cover portion made of metal that surrounds the electrode unit, The first cover portion is a first insertion opening for inserting the object to be heated into the first cover portion; a first outlet for delivering the object to be heated to the outside of the first cover portion; a plurality of first openings different from the first insertion opening and the first delivery opening, The dielectric heating device further comprises: a moving unit configured to be able to move the electrode unit back and forth in a fourth direction that intersects with the first direction and is perpendicular to the second direction; a third cover part made of metal that is disposed within the first cover part, covers the electrode unit, and faces the object to be heated that is transported in the first direction in the second direction; The third cover portion is The electrode unit is configured to be reciprocally movable in the fourth direction together with the electrode unit, a third opening that opens in the second direction toward the object to be heated and surrounds the first electrode and the second electrode when viewed along the second direction; and a plurality of fourth openings different from the third openings. Dielectric heating device.

4. The dielectric heating device according to claim 1 or 2, a moving section configured to reciprocate the electrode unit in a fourth direction that intersects with the first direction and is perpendicular to the second direction;

5. The dielectric heating device according to any one of claims 1 to 4, a second cover portion made of metal that surrounds the first cover portion; The second cover portion is a second insertion opening for inserting the object to be heated into the second cover portion; a second outlet for delivering the object to be heated to the outside of the second cover portion; a plurality of second openings different from the second insertion opening and the second delivery opening, Dielectric heating device.

6. 6. The induction heating device according to claim 5, A dielectric heating device, wherein the sum of the opening areas of the second openings is greater than the sum of the opening areas of the first openings.

7. 7. The dielectric heating device according to claim 1, A plurality of the electrode units is provided, The dielectric heating device, wherein the plurality of electrode units are arranged side by side in a third direction that intersects the first direction and is perpendicular to the second direction.

8. The dielectric heating device according to any one of claims 1 to 7, The first cover portion is formed of zinc.

9. 9. The dielectric heating device according to claim 1, An induction heating device comprising an airflow generating unit that generates an airflow within the first cover unit.

10. a conveying unit that conveys the object to be heated; an electrode unit having a first electrode and a second electrode, the electrode unit facing the object to be heated in a second direction intersecting the first direction and to which an AC voltage is applied; a moving unit configured to be able to move the electrode unit back and forth in a fifth direction that intersects with the first direction and is perpendicular to the second direction; a fourth cover portion made of metal that faces the object to be heated transported in the first direction in the second direction and covers the electrode unit; a metal opposing portion facing the first electrode and the second electrode across the object to be heated in a direction along the second direction, The fourth cover portion is The electrode unit is configured to be reciprocally movable in the fifth direction together with the electrode unit, a fifth opening that opens in the second direction toward the object to be heated and surrounds the first electrode and the second electrode when viewed along the second direction; Dielectric heating device.

11. The dielectric heating device according to any one of claims 1 to 10; a liquid ejection unit that ejects liquid onto a print medium, The transport unit transports the printing medium having the liquid attached thereto as the object to be heated.

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