Drying device and recording device

Abstract

To provide a dryer that can more uniformly heat a liquid attached to a recording medium.SOLUTION: A dryer is arranged at a predetermined interval from a recording medium, and includes a heater that dries a liquid applied to the recording medium by high-frequency waves. The heater has a first electrode connected with a power supply that outputs the high-frequency waves, and a second electrode connected with the power supply that outputs the high-frequency waves and arranged separate from the first electrode at a predetermined interval. The distance between an end of the first electrode and the recording medium is longer than the distance between a center part of the first electrode and the recording medium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drying device and a recording device. [Background technology]

[0002] Various types of printing apparatuses have been developed. Furthermore, various studies have been conducted not only on the printing apparatus itself but also on the configuration of the printing apparatus. For example, a mechanism for quickly drying ink adhered to the printing medium has been studied.

[0003] For example, Patent Document 1 discloses a high-frequency dielectric heating device that dries ink adhered to a medium by applying an AC electric field to the medium and dielectrically heating it. The device disclosed in Patent Document 1 describes that a hole is formed in one of a pair of electrodes to which high-frequency waves are input, and the other electrode is positioned within the hole, thereby enabling isotropic heating and uniform drying regardless of the print pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-016742 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when high frequency waves are generated, the generated electromagnetic field generally has an uneven intensity distribution, which also results in a distribution in the intensity of the dielectric heating. For example, even in the high frequency dielectric heating device described in Patent Document 1, the electromagnetic field generated by the two electrodes inherently has unevenness, and it is not always possible to achieve sufficiently uniform heating. Therefore, a drying device that can more uniformly heat the liquid attached to the recording medium is desired. [Means for solving the problem]

[0006] One aspect of the drying device according to the present invention is A drying device including a heater disposed at a predetermined distance from a recording medium and drying a liquid applied to the recording medium by high frequency waves, the heater has a first electrode connected to a power supply that outputs the high frequency wave, and a second electrode that is connected to a power supply that outputs the high frequency wave and is disposed at a predetermined distance from the first electrode, The distance between the end of the first electrode and the recording medium is longer than the distance between the center of the first electrode and the recording medium.

[0007] One aspect of the recording device according to the present invention is A plurality of the above drying devices is provided, The drying devices are each disposed at the predetermined interval from the recording medium. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically showing a heater according to a first embodiment. [Figure 2] FIG. 2 is a perspective view schematically showing a first electrode of the heater according to the first embodiment. [Figure 3] FIG. 2 is a schematic cross-sectional view of the first electrode of the heater according to the first embodiment, taken along the YZ plane. [Figure 4] FIG. 3 is a schematic diagram of a part of a cross section of a first electrode of the heater according to the first embodiment, taken along an XZ plane. [Figure 5] FIG. 10 is a perspective view schematically showing a heater according to a second embodiment. [Figure 6] FIG. 10 is a schematic cross-sectional view of the first electrode of the heater according to the second embodiment, taken along the YZ plane. [Figure 7] FIG. 10 is a perspective view schematically showing a heater according to a third embodiment. [Figure 8] FIG. 11 is a plan view of a heater according to a third embodiment, as viewed from the direction along the Z axis. [Figure 9] 10 shows a simulation result of the heat amount distribution of the heater according to the first embodiment. [Figure 10] FIG. 10 is a perspective view schematically showing a heater according to a comparative example. [Figure 11] 10 is a simulation result of the heating amount distribution of a heater according to a comparative example. [Figure 12A] 10 shows simulation results of the electric field distribution of the heater according to the first embodiment. [Figure 12B] 10 is a simulation result of the electric field distribution of a heater according to a comparative example. [Figure 13A] 10 shows simulation results of power consumption distribution of a heater according to the second embodiment. [Figure 13B] 10 is a simulation result of power consumption distribution of a heater according to a comparative example. [Figure 14] 10 shows a simulation result of the heat amount distribution of the heater according to the third embodiment. [Figure 15] FIG. 1 is a schematic diagram of a main part of an example of a recording apparatus according to an embodiment. [Figure 16] FIG. 2 is a perspective view schematically showing a drying area and its surroundings of the recording apparatus according to the embodiment. [Figure 17] FIG. 2 is a perspective view schematically showing a drying area and its surroundings of the recording apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below. The embodiment described below is an example of the present invention. The present invention is not limited to the following embodiment, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0010] 1.Drying equipment The drying device according to this embodiment is a drying device equipped with a heater that is disposed at a predetermined distance from a recording medium and dries a liquid applied to the recording medium using high-frequency waves. The heater has a first electrode connected to a power source that outputs high-frequency waves, and a second electrode that is also connected to the power source that outputs high-frequency waves and disposed at a predetermined distance from the first electrode, and the distance between the end of the first electrode and the recording medium is longer than the distance between the center of the first electrode and the recording medium. Each component will be described below in order with reference to the drawings.

[0011] The drying apparatus of this embodiment includes a heater. The drying apparatus of this embodiment also includes a high-frequency power supply (not shown). The high-frequency power supply includes a high-frequency voltage generating circuit. The high-frequency power supply generates a high-frequency voltage to be applied to the heater. The high-frequency power supply is configured, for example, with a crystal oscillator, a PLL (Phase Locked Loop) circuit, and a power amplifier. The high-frequency voltage generated by the high-frequency power supply is supplied to the heater via, for example, a resonant circuit and a coaxial cable. The basic peripheral circuit configuration of the high-frequency power supply of the drying apparatus of this embodiment is a configuration in which a high-frequency signal generated in a PLL circuit is amplified by a power amplifier and then supplied to the heater.

[0012] 1.1. Heater (First Embodiment) FIG. 1 is a schematic diagram of a heater 100 of a drying device according to a first embodiment. The drying device according to the first embodiment includes a heater 100. The heater 100 includes a first electrode 10, a second electrode 20, and a coil 30. One end of the coil 30 is electrically connected to the first electrode 10, and the other end is electrically connected to a high-frequency power supply. In the illustrated example, the other end of the coil 30 is electrically connected to the high-frequency power supply via an inner conductor 50 of a coaxial cable. The second electrode 20 is electrically connected to the high-frequency power supply via, for example, an outer conductor (not shown) of the coaxial cable.

[0013] 1.1.1. First Electrode and Second Electrode The first electrode 10 and the second electrode 20 are conductors. The first electrode 10 and the second electrode 20 form a capacitor. One of the potentials applied to the first electrode 10 or the second electrode 20 may be a reference potential. In this case, the other of the potentials applied to the first electrode 10 or the second electrode 20 is a high-frequency voltage. In this specification, an electrode to which a reference potential is applied may be referred to as a "reference potential electrode," and an electrode to which a high-frequency voltage is applied may be referred to as a "high-frequency electrode." The reference potential is a constant potential that serves as a reference for the high-frequency voltage, and may be, for example, ground potential.

[0014] A high-frequency voltage with a frequency of 1 MHz or higher is effective in heating the object. However, when the object to be heated is water, the dielectric loss tangent is maximized at a frequency of around 20 GHz, and the heating efficiency resulting from the dielectric loss tangent is also maximized. On the other hand, from the perspective of heating ink, good heating efficiency can be achieved even at a low frequency, such as 40.68 MHz, which is part of the ISM band. This is because, although the dielectric loss tangent of water in ink is very low at 40.68 MHz, a large amount of heat is generated due to resistance losses caused by eddy currents flowing in the electrical resistance of the liquid on the recording medium.

[0015] Furthermore, the higher the high-frequency voltage, the greater the amount of heat supplied to the liquid. However, since the high-frequency voltage is normally transmitted to the heater 100 via a 50 Ω transmission line, the high-frequency voltage input to the heater 100 is a voltage expressed as "high-frequency power = V^2 / R = V^2 / 50."

[0016] Furthermore, in order to reduce the amount of heat generated by the parasitic resistance of the heaters 100 and to prevent corona discharge, it is preferable that the drying device include multiple heaters 100 with a power of approximately several hundred watts. This allows the drying device to obtain the effects of reducing the amount of heat generated by the parasitic resistance of the heaters 100 and preventing corona discharge while ensuring the power required to dry the liquid. The liquid is also heated by the electric field generated between the first electrode 10 and the second electrode 20. The electric field generated between the first electrode 10 and the second electrode 20 has a very large value of approximately 1×10^6 V / m.

[0017] When the heater 100 is used, a recording medium such as paper, film, fabric, or the like is placed so as to face the first electrode 10 and the second electrode 20. Explaining with reference to Fig. 1, the recording medium is placed below the first electrode 10 and the second electrode 20, i.e., in the negative direction of the Z axis, substantially parallel to the first electrode 10 and the second electrode 20 so as not to come into contact with them.

[0018] The distance between the end of the first electrode 10 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium.

[0019] In this specification, the term "plan view" means "a plan view seen in the direction from the positive to the negative side of the Z axis."

[0020] The central portion of the first electrode 10 refers to a specific range extending from the center of gravity of the first electrode 10 toward the edge (outline) of the first electrode 10 in a plan view of the first electrode 10. In addition, in a plan view, the outline of the central portion of the first electrode 10 is a similar shape to the outline of the first electrode 10. In addition, in a plan view, the intersection of the line segment connecting the center of gravity and the outline of the first electrode 10 and the outline of the central portion of the first electrode 10 is located at a position 10% of the length of the line segment from the center of gravity.

[0021] Furthermore, the distance between the end of the first electrode 10 and the recording medium refers to the distance in the Z-axis direction between the lower surface of the end of the first electrode 10 and the surface of the recording medium when the recording medium is placed relative to the heater 100. Similarly, the distance between the center of the first electrode 10 and the recording medium refers to the distance in the Z-axis direction between the lower surface of the center of the first electrode 10 and the surface of the recording medium when the recording medium is placed relative to the heater 100.

[0022] The first electrode 10 may have a substantially flat plate shape as long as the distance between the end of the first electrode 10 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium. On the other hand, the second electrode 20 has a flat plate shape.

[0023] As long as the distance between the end of the first electrode 10 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium, the shapes of the first electrode 10 and the second electrode 20 in a plan view are arbitrary, and may be, for example, square, rectangular, circular, or a combination of these shapes. In the illustrated example, the second electrode 20 is disposed so as to surround the first electrode 10 in a plan view. By having the second electrode 20 surround the first electrode 10 in this manner, radiation of the far-field electromagnetic field can be suppressed. This makes it possible to maintain the level of the electromagnetic field to which workers around the drying device are exposed at a sufficiently safe level without providing an electromagnetic shield.

[0024] The first electrode 10 of the heater 100 has an elongated oval shape in a planar view. The second electrode 20 of the heater 100 has an oval shape with a hollowed-out center. In a planar view, the second electrode 20 is disposed so as to surround the first electrode 10. It is desirable that the shape of the first electrode 10 has as few sharp corners as possible. This is to prevent the electric field from concentrating at the corners of the first electrode 10 and inducing corona discharge. The distance between the end of the first electrode 10 of the heater 100 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium, thereby inducing corona discharge.

[0025] Furthermore, although not shown, the first electrode 10 and the second electrode 20 may be arranged adjacent to each other in any shape in a plan view. In this case, the size of the first electrode 10 and the second electrode 20 in a plan view is 0.01 cm2 as the area in a plan view of one electrode. 2 More than 100.0cm 2 Less than 0.1cm, preferably 0.1cm 2 More than 10.0cm 2 Less than 0.5cm, preferably 0.5cm 2 More than 2.0cm 2 Less than 0.5cm, more preferably 2 More than 1.0cm 2The above-mentioned areas are for a frequency of 2.45 GHz, and the electrode areas increase when the frequency used is lowered. Furthermore, the areas of the first electrode 10 and the second electrode 20 in a plan view may be the same or different.

[0026] In the heater 100, a high-frequency voltage and a reference potential are supplied to a first electrode 10 having an oval shape disposed at the center in a plan view and a second electrode 20 having an oval shape with a hollow center surrounding the first electrode 10. A coil 30 is inserted between the first electrode 10 and the inner conductor 50 of the coaxial cable. It is preferable that the distance between the coil 30 and the first electrode 10 is as short as possible.

[0027] The first electrode 10 and the second electrode 20 are preferably arranged so as not to overlap in a plan view. In the illustrated example, the central bottom surface of the first electrode 10 and the bottom surface (the surface facing the recording medium) of the second electrode 20 are arranged on the same plane. By arranging them in this way, it is possible to efficiently radiate a predetermined electromagnetic wave to the recording medium.

[0028] The first electrode 10 and the second electrode 20 are primarily composed of a material such as a metal, alloy, or conductive oxide. The first electrode 10 and the second electrode 20 may be made of the same material or different materials. The first electrode 10 and the second electrode 20 may be configured with thickness and strength selected appropriately so that they can stand on their own. If maintaining their strength is difficult, they may be formed on the surface of a substrate or the like (not shown) made of a material with a low dielectric tangent that transmits electromagnetic waves. In the example of FIG. 1, the second electrode 20 is supported by a support member 40.

[0029] The intensity of the electromagnetic waves emitted from the heater 100 is very strong near the first electrode 10 and the second electrode 20 and very weak farther away. In this specification, the electromagnetic field generated near the first electrode 10 and the second electrode 20 by the heater 100 is sometimes referred to as the "near electromagnetic field." Also, in this specification, the electromagnetic field generated by a general heater (antenna) designed to transmit electromagnetic waves farther away is sometimes referred to as the "far electromagnetic field." The boundary between the near and far fields is located at a distance from the heater 100 that is approximately 1 / 6 of the wavelength of the generated electromagnetic waves.

[0030] The heater 100 does not emit electromagnetic waves at intervals of meters, and the electric field density of the electromagnetic waves attenuates to 30% or less of the electric field density between the first electrode 10 and the second electrode 20 while traveling a distance of 1 / 6 of the wavelength. Therefore, unnecessary radiation is unlikely to occur in areas farther from the device than a distance approximately equal to the wavelength of the generated electromagnetic waves.

[0031] When the drying apparatus includes multiple heaters 100, for example, one power amplifier may be used for each heater 100. The output of the PLL circuit may be divided and supplied to multiple power amplifiers to generate electromagnetic waves for each heater 100. Furthermore, when the drying apparatus includes multiple pairs of heaters 100 and power amplifiers, the high-frequency output of each heater 100 can be more easily controlled individually.

[0032] 1.1.2. Coil The heater 100 includes a coil 30 connected in series to the first electrode 10 via an electric wire 55. The first electrode 10 is connected via the coil 30 to a path through which a high-frequency voltage is applied. One end of the coil 30 is electrically connected to the first electrode 10, and the other end is electrically connected in series to a high-frequency power supply. Even with the same inductance, the heating energy efficiency of the coil 30 varies significantly depending on its serial insertion position. Therefore, it is desirable to install the coil 30 as close to the first electrode 10 as possible. Here, the serial insertion position refers to the position where the coil 30 is inserted in series between the electric wire 55 and the first electrode 10. In other words, because a high voltage is generated at one end of the coil 30, a strong electric field may be generated between the coil 30 and the first electrode 10, or between the electric wire 55 connecting the coil 30 and the first electrode 10 and the second electrode 20. Because such an electric field does not contribute to heating, it is preferable to position the coil 30 as close to the first electrode 10 as possible.

[0033] By having the coil 30 in the heater 100, it is possible to expect the following effects: changing the impedance of the resonant circuit to match the impedance of the resonant circuit with the impedance of the heater 100; increasing the electric field generated between the electrodes; and strengthening the electric field generated by the coil 30 by adding it to the electric field generated between the electrodes.

[0034] 1.1.3. Radius of curvature of the edge of the first electrode 1, the first electrode 10 has a longitudinal direction (X direction in the figure) and a lateral direction (Y direction in the figure) in a plan view. When the first electrode 10 has a longitudinal direction and a lateral direction in this way, it is preferable that the radius of curvature of the end of the first electrode 10 in the longitudinal direction is larger than the radius of curvature of the end of the first electrode 10 in the lateral direction.

[0035] FIG. 2 is an enlarged schematic diagram of the first electrode 10, FIG. 3 is a schematic diagram of a cross section of the first electrode 10 shown in FIG. 2 taken along the YZ plane, and FIG. 4 is a schematic diagram of a portion of the cross section of the first electrode 10 shown in FIG. 2 taken along the XZ plane.

[0036] 3 and 4, the radius of curvature r of the short-side end of the first electrode 10 is smaller than the radius of curvature R of the long-side end of the first electrode 10. By doing so, the long-side end of the first electrode 10, where the electromagnetic field intensity is more likely to concentrate when high frequency is applied, moves more gradually away from the second electrode 20, thereby achieving a significant effect of mitigating the concentration of the electromagnetic field intensity. This further reduces the likelihood of uneven heating on the recording medium facing the first electrode 10 and the second electrode 20.

[0037] 1.2. Heater (Second embodiment) FIG. 5 is a schematic diagram of a heater 110 according to a second embodiment. The heater 110 is depicted without a coil. FIG. 6 is a schematic diagram of a cross section of the first electrode 10a of the heater 110 taken along the ZX plane. The heater 110 of the second embodiment also has a first electrode 10a and a second electrode 20a. The heater 110 has the same function as the heater 100 of the first embodiment, except that the shapes of the first electrode 10a, the second electrode 20a, and the support member 40a of the heater 110 are different from those of the first electrode 10, the second electrode 20, and the support member 40 of the heater 100 of the first embodiment. The first electrode 10a is electrically connected to a high-frequency power supply via the inner conductor 50 of a coaxial cable. The second electrode 20a is also electrically connected to the high-frequency power supply via the support member 40a.

[0038] As shown in Fig. 6, in the heater 110, the first electrode 10a is also shaped such that its ends are away from the recording medium. That is, the distance between the ends of the first electrode 10a and the recording medium is longer than the distance between the center of the first electrode 10a and the recording medium. In the heater 110, the first electrode 10a is shaped such that its ends are away from the recording medium, and the center is flat. The second electrode 20a is also flat.

[0039] In the heater 110, the first electrode 10a and the second electrode 20a have a circular shape in a plan view. In the illustrated example, the circular first electrode 10a is arranged so that the annular second electrode 20a surrounds the circular first electrode 10a in a plan view. In the heater 110, the radiation of a far electromagnetic field is also suppressed by the second electrode 20a surrounding the first electrode 10a. Regarding the size of the electrodes of the heater 110, it is preferable that the diameter of the first electrode 10a is 1 cm or more and 10 cm or less, the outer diameter of the second electrode 20a is 1 cm or more and 20 cm or less, and the gap between them is approximately 1 cm or more and 5 cm or less.

[0040] 1.3. Heater (Third embodiment) FIG. 7 is a schematic diagram of a heater 120 according to a third embodiment. FIG. 8 is a schematic plan view of the heater 120 according to the third embodiment. The heater 120 according to the third embodiment has a floating electrode 60. The heater 120 is similar to the heater 100 according to the above-described embodiment except for the fact that it has the floating electrode 60. Therefore, the same components as those of the heater 100 are denoted by the same reference numerals and will not be described again. In this specification, the floating electrode 60 is also referred to as a third electrode.

[0041] 7 shows an example of a floating electrode 60. The floating electrode 60 is disposed between an oval first electrode 10 and an oval ring-shaped second electrode 20. The floating electrode 60 is not electrically connected to the first electrode 10 or the second electrode 20, and is supported by an insulator (not shown). The floating electrode 60 has an oval ring shape.

[0042] The floating electrode 60 is not electrically connected to a high-frequency power supply, ground, a reference signal source, or the like, and has an independent potential. By disposing the floating electrode 60, which is a conductor, between the first electrode 10 and the second electrode 20, the strength of the electromagnetic field generated between the first electrode 10 and the second electrode 20 is made uniform in the XY plane. This is because the floating electrode 60 converts the electric field between the electrodes into an eddy current. This further reduces unevenness in the strength of the electromagnetic field generated between the first electrode 10 and the second electrode 20.

[0043] Simulation Fig. 9 shows the results of a simulation of the heat amount distribution of the heater 100 according to the first embodiment. Fig. 10 is a schematic diagram of a heater 130 according to a comparative example in which the distance between the end of the first electrode 10b and the recording medium is not longer than the distance between the center of the first electrode 10b and the recording medium. Fig. 11 shows the results of a simulation of the heat amount distribution of the heater 130 according to the comparative example.

[0044] A heater 130 according to a comparative example shown in Fig. 10 has a first electrode 10b and a second electrode 20. The heater 130 has the same function as the heater 100 of the first embodiment, except that the shape of the first electrode 10b is different from that of the first electrode 10 of the first embodiment. The first electrode 10b is electrically connected to a high-frequency power supply via the inner conductor 50 of a coaxial cable. The second electrode 20 is also electrically connected to the high-frequency power supply.

[0045] 10, the heater 130 of the comparative example does not have a shape in which the distance between the end of the first electrode 10b and the recording medium is longer than the distance between the center of the first electrode 10b and the recording medium. In other words, the distance between the end of the first electrode 10b and the recording medium is the same as the distance between the center of the first electrode 10b and the recording medium.

[0046] FIG. 11 shows the results of a simulation of the heat amount distribution of the heater 130 of the comparative example in a plan view. As shown in FIG. 11, the heater 130 heats an oval ring-shaped area on the recording medium between the first electrode 10b and the second electrode 20. However, there is an area where the heat amount is concentrated near the outline of the first electrode 10b. In such cases, it can be seen that uneven heating of the liquid on the recording medium is likely to occur. Note that there is also a heated area within the outlines of the first electrode 10b and the second electrode 20.

[0047] In contrast, the simulation results ( FIG. 9 ) of the heat amount distribution of the heater 100 of the first embodiment in a plan view show that the heater 100 heats an oval ring-shaped region between the first electrode 10 and the second electrode 20 on the recording medium. However, the concentration of the heat amount near the contour of the first electrode 10 is suppressed compared to the heater 130 of the comparative example, and the heat amount is averaged. As such, the distance between the end of the first electrode 10 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium, which reduces the likelihood of uneven heating of the liquid on the recording medium. Note that in FIG. 9 , a prominent heated region is observed within the contour of the first electrode 10, and a larger heated region is also observed within the contour of the second electrode 20 than in the heater 130 of the comparative example. This is thought to be due to the shape of the heater 100 of the first embodiment, in which the distance between the end of the first electrode 10 and the recording medium is longer than the distance between the center of the first electrode 10 and the recording medium.

[0048] FIG. 12A shows the results of a simulation of the electric field distribution of the first electrode 10 of the heater 100 of the first embodiment. FIG. 12B shows the results of a simulation of the electric field distribution of the first electrode 10b of the heater 130 of the comparative example. FIGS. 12A and 12B show a side view (Y direction) and an enlarged view of the vicinity of the end of the electrode. From FIG. 12, it can be seen that in the heater 100 of the first embodiment, the electric field is spread around the end of the first electrode 10, and concentration is alleviated. In contrast, in the heater 130 of the comparative example, the electric field is concentrated at the end of the first electrode 10b.

[0049] FIG. 13A shows the results of a simulation of the power consumption distribution of the first electrode 10a of the heater 110 of the second embodiment. FIG. 13B shows the results of a simulation of the power consumption distribution of a comparative example in which the first electrode 10a of the heater 110 of the second embodiment is flat. In the heater of the comparative example simulated in FIG. 13B, the distance between the end of the first electrode 10a and the recording medium is the same as the distance between the center of the first electrode 10a and the recording medium, but this is not shown. FIGS. 13A and 13B are shown in plan view. Both FIGS. 13A and 13B show that power consumption occurs in the annular region between the first and second electrodes, resulting in heating. Furthermore, FIG. 13A shows that the power consumption distribution extends to the inside of the electric field contour of the first electrode 10, mitigating spatial concentration of power consumption. In contrast, FIG. 13B shows that power consumption is concentrated at the end of the first electrode.

[0050] Fig. 14 shows the results of a simulation of the heat amount distribution of the heater 120 of the third embodiment. As shown in Fig. 14, the heater 120 heats the oval ring-shaped area between the first electrode 10 and the second electrode 20 on the recording medium, but the amount of heat in the area corresponding to the floating electrode 60 is suppressed, which is thought to further mitigate the concentration of the heat amount.

[0051] 1.5.Effects The drying device of this embodiment can suppress uneven heating of the liquid placed on the recording medium when high frequency waves are applied. That is, by making the distance between the end of the first electrode of the heater provided in the drying device and the recording medium longer than the distance between the center of the first electrode and the recording medium, it is possible to reduce the strong electromagnetic field generated near the end of at least one of the electrodes and disperse the electromagnetic field toward positions away from both electrodes.

[0052] 2. Recording device The recording apparatus according to this embodiment includes a plurality of drying devices according to the above-described embodiment. Each of the drying devices is disposed at a predetermined distance from the recording medium. An inkjet recording apparatus 1000 will be described below as an example of the recording apparatus with reference to the drawings.

[0053] 15 is a schematic cross-sectional view showing the main components of an inkjet recording apparatus 1000 according to an embodiment. The inkjet recording apparatus 1000 includes an inkjet head 200 that applies an ink composition to a recording medium M, a plurality of heaters 100 of drying devices, a movement mechanism 300 that moves the heaters 100 along the recording medium M, a transport roller T, and a guide roller G.

[0054] Although not shown, the inkjet recording apparatus 1000 also includes a carriage that moves the inkjet head 200 back and forth in a direction intersecting the conveying direction SS of the recording medium M, and a control unit that controls the entire apparatus.

[0055] The inkjet head 200 is configured to perform recording by ejecting a predetermined ink composition from nozzles and depositing it on the recording medium M. In this embodiment, the inkjet head 200 is a serial inkjet head that scans multiple times in the main scanning direction (depth direction in FIG. 15) relative to the recording medium M to apply the ink composition to the recording medium M. The inkjet head 200 is scanned multiple times in the main scanning direction relative to the recording medium M by moving the carriage in the medium width direction of the recording medium M. The medium width direction is the main scanning direction of the inkjet head 200. Scanning in the main scanning direction is also called main scanning.

[0056] Here, the main scanning direction is the direction in which the carriage carrying the inkjet head 200 moves. In Figure 15, this is the direction that intersects with the sub-scanning direction, which is the direction in which the recording medium M is transported. While the main scanning of the inkjet head 200 and the sub-scanning, which is the transport of the recording medium M, are repeated multiple times, ink is ejected from the inkjet head 200 at predetermined timing to deposit the ink at predetermined positions on the recording medium M, thereby performing recording on the recording medium M.

[0057] A predetermined ink composition or the like is supplied to the inkjet head 200 appropriately using a cartridge or the like.

[0058] The method for ejecting ink droplets is not limited to the ejection method of the inkjet head 200, and any conventionally known method can be used. In this embodiment, a method for ejecting droplets using the vibration of a piezoelectric element, that is, an ejection method for forming ink droplets by mechanical deformation of an electrostrictive element, is used.

[0059] The inkjet recording apparatus 1000 has a recording area P where an ink composition is applied to a recording medium M by an inkjet head 200, and a drying area D where the recording medium M that has passed through the recording area P is dried.

[0060] In the drying region D, multiple heaters 100 are arranged facing the recording medium M. Each heater 100 is mounted on a movement mechanism 300. The movement mechanism 300 can move the heater 100 in any direction while maintaining the distance between the heater 100 and the recording medium M. The heater 100 may be arranged on the ink-adhered surface side of the recording medium M, or on the opposite side from the ink-adhered surface. Furthermore, the heater 100 may be arranged on both sides of the recording medium M.

[0061] In the drying region D, the ink composition deposited on the recording medium is dried by the heater 100 to form a recorded matter. Since the inkjet recording apparatus 1000 is provided with the heater 100 described above, uneven heating of the liquid such as ink deposited on the recording medium M can be suppressed.

[0062] 16 and 17 are schematic perspective views of the drying region D and its vicinity of the inkjet recording apparatus 1000. In the example of FIGS. 16 and 17, nine heaters 100 are mounted on each of the movement mechanisms 300. In the inkjet recording apparatus 1000, as shown in the figures, the heaters 100 are arranged alternately to prevent gaps from forming when viewed along the conveyance direction SS of the recording medium M. In the inkjet recording apparatus 1000, uneven heating caused by individual heaters 100 is suppressed, but the areas between heaters 100 arranged side by side may be difficult to heat. Therefore, in the inkjet recording apparatus 1000, the multiple heaters 100 are arranged so as to prevent areas from being underheated in the width direction when the recording medium M is conveyed.

[0063] 3. Oscillating the dryer In the inkjet recording apparatus 1000, the heater 100 may be oscillated while maintaining a predetermined distance from the recording medium M by driving the movement mechanism 300. The oscillation mode of the heater 100 includes a mode in which the heater 100 moves back and forth along the conveyance direction SS of the recording medium M (schematically shown by the arrow "A" in FIG. 17), a mode in which the heater 100 moves back and forth along a direction intersecting the conveyance direction SS of the recording medium M (schematically shown by the arrow "B" in FIG. 17), and a mode in which the heater 100 moves circularly in a clockwise or counterclockwise direction (schematically shown by the arrow "C" in FIG. 17). These movement modes can be combined, and the movement amount is also arbitrary.

[0064] By oscillating the heater 100 while maintaining a predetermined distance from the recording medium M, it is possible to further suppress uneven heating that occurs in the area between the heaters 100 arranged side by side. Furthermore, since the inkjet recording apparatus 1000 is a serial printer as described above, the recording medium M is transported intermittently. As a result, the recording medium M may become stationary in the drying area. In such a case, even if the recording medium M is stationary, the heater 100 oscillates, thereby reducing uneven heating on the recording medium M.

[0065] Furthermore, the distance traveled by the movement mechanism 300 to move the multiple heaters 100 back and forth is preferably equal to the distance traveled by one transfer of the recording medium M in the transport direction SS. For example, when the inkjet head 200 is mounted on a carriage, the inkjet head 200 moves back and forth in the width direction of the recording medium to form a print pattern. Therefore, if the heater 100 is not moved back and forth, depending on the amount of transport of the recording medium M, some areas of the recording medium M will remain directly below the heater 100 for a long time and others will remain directly below the heater 100 for a short time, which could lead to uneven heating. By making the distance traveled by the movement mechanism 300 to move the multiple heaters 100 back and forth equal to the distance traveled by one transfer of the recording medium M, the time each area of ​​the recording medium M remains directly below the heater 100 will be equal, thereby reducing uneven heating.

[0066] In the above, the inkjet recording device 1000 has been described as being a serial type printer, but the inkjet recording device may also be a line type printer, in which case it is also possible to easily obtain recorded material with reduced heating unevenness.

[0067] The above-described embodiment and modified embodiments are merely examples, and the present invention is not limited to these. For example, the embodiments and modified embodiments can be appropriately combined.

[0068] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations that add publicly known technology to the configurations described in the embodiments.

[0069] The following can be derived from the above.

[0070] One aspect of the drying device is A drying device including a heater disposed at a predetermined distance from a recording medium and drying a liquid applied to the recording medium by high frequency waves, the heater has a first electrode connected to a power supply that outputs the high frequency wave, and a second electrode that is connected to a power supply that outputs the high frequency wave and is disposed at a predetermined distance from the first electrode, The distance between the end of the first electrode and the recording medium is longer than the distance between the center of the first electrode and the recording medium.

[0071] This drying device can heat the liquid on the recording medium uniformly when high-frequency waves are applied. Specifically, by making the distance between the end of the first electrode and the recording medium longer than the distance between the center of the first electrode and the recording medium, the strong electromagnetic field generated near the end of at least one of the electrodes can be alleviated and dispersed toward positions away from both electrodes. This makes it less likely that uneven heating will occur on the recording medium facing one drying device.

[0072] In the drying device, When viewed from the normal direction of the recording medium, the first electrode has a longitudinal direction and a lateral direction, The radius of curvature of the end of the first electrode in the longitudinal direction may be larger than the radius of curvature of the end of the first electrode in the lateral direction.

[0073] With this drying device, the longitudinal end of the first electrode, where the electromagnetic field intensity is more likely to concentrate when high frequency waves are applied, moves gradually away from the second electrode, which significantly reduces the effect of mitigating the concentration of the electromagnetic field intensity, thereby further reducing uneven heating on the recording medium facing one drying device.

[0074] In the drying device, a third electrode between the first electrode and the second electrode; The third electrode may not be connected to the power supply.

[0075] This drying device can further reduce unevenness in the strength of the electromagnetic field generated between the first electrode and the second electrode.

[0076] The recording apparatus includes a plurality of the drying devices described above, The plurality of drying devices may be arranged side by side in a direction intersecting the conveying direction of the recording medium.

[0077] This recording apparatus can dry liquid such as ink adhered to the recording medium uniformly.

[0078] In the above recording device, The drying device may be oscillated while maintaining the predetermined distance from the recording medium.

[0079] This recording device can further reduce uneven heating of the liquid on the recording medium. That is, by oscillating multiple drying devices, it is possible to reduce uneven heating between an area heated by one drying device and an area between adjacent drying devices that is difficult to heat.

[0080] In the above recording device, The recording device may be a serial type inkjet recording device.

[0081] According to this recording device, even if the recording medium is conveyed intermittently and is stationary, the drying device oscillates, thereby reducing uneven heating on the recording medium. [Explanation of symbols]

[0082] 10, 10a, 10b...first electrode, 20, 20a...second electrode, 30...coil, 40...support member, 50...internal conductor, 55...electric wire, 60...floating electrode, 100, 110, 120, 130...heater, 200...inkjet head, 300...movement mechanism, M...recording medium, r, R...radius of curvature, T...transport roller, G...guide roller, P...recording area, D...drying area, SS...transport direction

Claims

1. The liquid is applied to the recording medium at a high frequency. A drying device equipped with a heater that dries by waves, The heater includes a first electrode connected to a power source that outputs the high frequency wave, and a second electrode connected to a power source that outputs the high frequency wave. a second electrode connected to a power source for supplying a voltage thereto and spaced apart from the first electrode by a predetermined distance; Has, The distance between the end of the first electrode and the recording medium is It is longer than the distance between When viewed from the normal direction of the recording medium, the first electrode has a longitudinal direction and a lateral direction, The radius of curvature of the end of the first electrode in the longitudinal direction is Larger than the radius of curvature of the end of one electrode A drying device characterized by:

2. In claim 1, a third electrode between the first electrode and the second electrode; A drying device, wherein the third electrode is not connected to the power supply.

3. In claims 1 and 2, The plurality of drying devices are arranged in a direction intersecting the conveying direction of the recording medium. A recording device comprising:

4. In claim 3, The drying device is characterized in that it oscillates while maintaining the predetermined distance from the recording medium. A recording device.

5. In claim 4, The recording apparatus is a serial type inkjet recording apparatus.

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