JP6733382B2 - High frequency dielectric heating device and image forming device - Google Patents

Description

The present invention relates to a high frequency dielectric heating device and an image forming apparatus.

In commercial inkjet printers, there are infrared heating such as heat drum/IR (NIR) and high frequency dielectric heating methods as a technique for drying the applied ink. Among them, the high frequency dielectric heating method heats more than other methods. It is known that there is little effect on paper due to, and it is more energy saving than other methods.

For example, Patent Document 1 discloses a technique for reducing the drying unevenness by arranging a plurality of feeding points on a flat plate electrode so as to average the voltage applied between the electrodes for the purpose of reducing the drying unevenness. There is.

However, the technique disclosed in Patent Document 1 has a problem in that the heating unit such as an electrode in the high frequency dielectric heating method is large, and thus the installation space is restricted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high-frequency dielectric heating device and an image forming apparatus that can realize miniaturization of a heating unit.

To solve the above problems and achieve the object, high-frequency dielectric heating apparatus of the present invention, at least a pair of electrodes a high frequency voltage is applied, the shape of the pair of electrodes Ri rod-der, the pair The electrode includes a first electrode to which high-frequency voltages having different polarities are alternately applied, and a second electrode connected to a ground line to which a ground voltage is supplied, and the first electrode and the first electrode Each of the two electrodes has a rod shape, the first electrode and the second electrode are arranged to face each other, and one end of one end of the first electrode is A high-frequency generator that generates a high-frequency voltage is connected, and one of the ends of the second electrode that is connected to the ground line has an end opposite to the end corresponding to the one end. It is a department.

According to the present invention, it is possible to provide a high-frequency dielectric heating device and an image forming apparatus that can realize downsizing of a heating unit.

FIG. 1 is a diagram showing an outline of the image forming apparatus. FIG. 2 is a diagram for explaining the configuration of the electrode portion of the embodiment. FIG. 3 is a diagram showing a configuration of an electrode portion having a contrast ratio of 1. FIG. 4 is a diagram showing an equivalent circuit of the proportional one. FIG. 5 is a diagram showing a configuration of an electrode portion having a contrast ratio of 2. FIG. 6 is a diagram showing the relationship between the distance from the power feeding point and the inter-electrode voltage in Comparative Example 2. FIG. 7 is a diagram illustrating an example of functions of the MFP of the modified example. FIG. 8 is a diagram showing an example of variations of the electrode portion. FIG. 9 is a diagram showing an example of the positional relationship between the electrodes and the paper. FIG. 10 is a diagram showing another example of the positional relationship between the electrodes and the paper.

Hereinafter, embodiments of a high frequency dielectric heating device and an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing an outline of an image forming apparatus 900 having a high frequency dielectric heating apparatus 100 of this embodiment. In the example of FIG. 1, the image forming apparatus 900 is an inkjet type image forming apparatus, and includes a paper feeding unit 800, an image forming unit 802, a high frequency dielectric heating device 100 as a fixing unit, and a paper discharging unit 804.

The sheet feeding unit 800 feeds a sheet (an example of a recording medium) from the sheet feeding tray, and conveys the sheet to the image forming unit 802 by a pair of rollers 901 (direction of arrow A).

The image forming unit 802 forms an image on a recording medium. In the example of FIG. 1, the image forming unit 802 conveys a sheet (in the direction of arrow B) by the conveyance belt 904 spanning the driving roller 902 and the driven roller 903 to form an unfixed image on the sheet. After that, the sheet is conveyed to the high frequency dielectric heating device 100.

In the image forming unit 802, recording heads 905 a to 905 d for ejecting black, cyan, magenta, and yellow inks are sequentially arranged in the transport direction of the transport belt 904. The recording heads 905a to 905d are formed with nozzles (line-type recording heads) at predetermined intervals over substantially the width of the sheet (the direction perpendicular to the recording sheet surface). Therefore, when the sheet is conveyed to the high frequency induction heating device 100 by the conveyor belt 904, a desired unfixed image is formed on the entire area of the sheet.

In the case of such an inkjet method, particularly when a color image is formed, the amount of ink ejected from the recording heads 905a to 905d becomes large, and it becomes difficult to perform rapid fixing of the ink by drying in a normal environment. Therefore, if the ink is conveyed to the paper ejection tray of the paper ejection unit 804 in a state where the ink is not dried (unfixed), the ink permeates (strike through) to the back surface of the paper during conveyance, which deteriorates the image. , Ink may be reflected on the back surface of other paper in the paper discharge tray (show-through), and other adverse effects may occur. When the image forming method is the electrophotographic method, the image forming unit 802 forms an unfixed toner image on the sheet through known charging, exposing, and developing processes.

The high-frequency dielectric heating device 100 conveys a sheet (in the direction of arrow C) by the conveyance belt 908 that is stretched between the driving roller 906 and the driven roller 907, and uses the electrode section 70 in the main body 909 to display an image on the sheet. After fixing, the paper is conveyed to the paper output unit 804. In the high frequency dielectric heating device 100, the distance between the electrode portion 70 and the paper can be set short and uniform, so that the heating and fixing efficiency and the fixing uniformity are excellent, and the degree of freedom in setting the high frequency application region is large.

The electrode unit 70 includes at least a pair of electrodes to which a high frequency voltage is applied. The specific configuration of the electrode unit 70 will be described later. Further, the controller 6 controls ON/OFF of the high frequency generator 1, voltage control, and the like.

The high-frequency dielectric heating device 100 conveys a sheet into an electric field generated in the electrode section 70 by alternately applying high-frequency voltages having different polarities (generated by the high-frequency generation section 1) to the electrode section 70, The principle of high-frequency dielectric heating heats the ink itself, the moisture in the paper, and the paper itself.

FIG. 2 is a diagram for explaining the configuration of the electrode section 70 of the present embodiment. In the present embodiment, the electrode unit 70 includes at least a pair of electrodes 71 to which a high frequency voltage is applied, and the pair of electrodes 71 has a rod shape. 2A is a perspective view of the pair of electrodes 71, and FIG. 2B is a plan view of the pair of electrodes 71.

More specifically, as shown in FIGS. 2A and 2B, the pair of electrodes 71 includes a first electrode 72 (in the following description, “high voltage side”) to which high frequency voltages having different polarities are alternately applied. And a second electrode 73 connected to a ground line 74 to which a ground voltage GND (typically 0 V, but any voltage that serves as a reference) may be supplied. (In the following description, it may be referred to as "ground-side rod-shaped electrode 73"), and each of the first electrode 72 and the second electrode 73 has a rod-like shape.

FIG. 3 is a diagram showing a configuration of an electrode portion having a contrast ratio of 1. As shown in FIG. 3, in Comparative Example 1, a high voltage electrode plate 80 and a ground electrode plate 81 facing each other are provided. High-frequency voltages having different polarities are alternately applied to the high-voltage electrode plate 80, and the ground electrode plate 81 is connected to the ground line 74. Further, as shown in FIG. 3, a plurality of high voltage side rod-shaped electrodes 72 are connected to the surface of the high voltage electrode plate 80. Further, on the surface of the ground electrode plate 81, a plurality of high-voltage side rod-shaped electrodes 72 and a plurality of ground-side rod-shaped electrodes 73 corresponding one-to-one are connected.

FIG. 4 is a diagram showing the equivalent circuit of FIG. 3 after tuning. As shown in FIG. 4, since the capacitance C23 between the parallel plate electrodes (the capacitance between the high voltage electrode plate 80 and the ground electrode plate 81) is large, the reactive power is large in comparison. Further, since the area to be heated is increased by increasing the area of the parallel flat plate, the heating module also becomes large. Further, in the case of Comparative Example 1, it is difficult to realize the miniaturization of the heating unit because the parallel flat plate is used.

On the other hand, in the present embodiment, since the high frequency dielectric heating is performed by using the electrode section 70 that does not include the parallel plate electrodes and uses the pair of rod-shaped electrodes 71 as a minimum module, the heating unit can be downsized. Can be realized. Moreover, since the reactive power and the heating module can be suppressed as compared with Comparative Example 1, it is also possible to realize a low power loss.

Further, as shown in FIG. 2B, in the present embodiment, the high voltage side rod-shaped electrode (first electrode) 72 and the ground side rod-shaped electrode (second electrode) 73 are arranged to face each other. In this example, the high frequency generation unit 1 that generates a high frequency voltage is connected to one end A of both ends of the high voltage side rod-shaped electrode 72. Further, one of the ends of the ground-side rod-shaped electrode 73, which is connected to the ground wire 74, is an end B opposite to the end C corresponding to the end A of the high-voltage-side rod-shaped electrode 72.

FIG. 5 is a diagram showing a configuration of an electrode portion having a contrast ratio of 2. As shown in FIG. 5, in Comparative Example 2, the high voltage side rod-shaped electrode 72 and the ground side rod-shaped electrode 73 are arranged to face each other. The high frequency generation unit 1 is connected to one end A of both ends of the high voltage side rod-shaped electrode 72. Further, a ground wire 74 is connected to an end C corresponding to the end A of the high voltage side rod-shaped electrode 72 among both ends of the ground side rod-shaped electrode 73. FIG. 6 is a diagram showing a relationship between a distance from a power feeding point (eg, a grounding point may be used) and an inter-electrode voltage in Comparative Example 2. As shown in FIG. 6, it can be seen that the larger the distance from the feeding point, the higher the value of the inter-electrode voltage, which should be constant.

FIG. 7 is a diagram showing the relationship between the distance from the feeding point and the inter-electrode voltage in this embodiment. As can be seen from FIG. 6 and FIG. 7, according to the present embodiment, it is possible to suppress the variation in the value of the inter-electrode voltage, as compared with the case of Comparative Example 2. That is, by making the connection point between the high-voltage side rod-shaped electrode 72 and the high-frequency generator 1 and the connection point between the grounded side rod-shaped electrode 73 and the ground wire 74 alternate, it is possible to suppress variations in inter-electrode voltage. ..

The number of the pair of electrodes 71 is arbitrary and is not limited to one. For example, as shown in FIG. 8, a plurality of pairs of electrodes 71 may be provided. In this case, the connection point between the high-voltage side rod-shaped electrode 72 and the high-frequency generator 1 and the connection point between the ground-side rod-shaped electrode 73 and the ground wire 74 are alternated over a plurality of groups (a pair of electrodes 71). Will be placed. As a result, it is possible to further suppress the heating unevenness while suppressing the variation in the voltage between the electrodes.

The positional relationship between the electrodes (first electrode 72, second electrode 73) and the object to be heated (paper in this example) can be arbitrarily changed according to design conditions and the like. For example, as shown in FIG. 9, the second electrode 73 may be arranged on the sheet and the first electrode 72 may be arranged on the second electrode 73. Further, for example, as shown in FIG. 10, a form in which a sheet is arranged between the first electrode 72 and the second electrode 73 may be adopted.

As described above, according to the present embodiment, it is possible to provide the high frequency dielectric heating device 100 and the image forming apparatus 900 that can realize the miniaturization of the heating unit.

Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments as they are, and constituent elements can be modified and embodied at the stage of implementation without departing from the scope of the invention. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment.

The rod-shaped electrodes (the first electrode 72 and the second electrode 73) described above may have various sectional shapes. For example, when the thickness of the object to be dried is small, it is more efficient to make the cross-sectional shape square, so it is desirable to make the cross-sectional shape square. That is, the cross-sectional shape of the rod-shaped electrode can be appropriately used (square, round, etc.) depending on the thickness, shape, conditions, drying purpose of the object to be dried.

DESCRIPTION OF SYMBOLS 1 High-frequency generator 6 Controller 70 Electrode 71 Pair of electrodes 72 First electrode 73 Second electrode 74 Ground wire 100 High-frequency dielectric heating device 900 Image forming apparatus

JP-A-63-53888

Claims (4)

At least a pair of electrodes to which a high frequency voltage is applied,
Said pair of electrodes shaped Ri rod-der,
The pair of electrodes,
First electrodes to which high-frequency voltages having different polarities are alternately applied,
A second electrode connected to a ground line to which a ground voltage is supplied, and
Each of the first electrode and the second electrode has a rod shape,
The first electrode and the second electrode are arranged to face each other,
A high-frequency generator that generates the high-frequency voltage is connected to one end of both ends of the first electrode,
One of the ends of the second electrode, which is connected to the ground line, is an end opposite to the end corresponding to the one end.
High frequency induction heating device. At least a pair of electrodes to which a high frequency voltage is applied,
Said pair of electrodes shaped Ri rod-der,
The pair of electrodes,
First electrodes to which high-frequency voltages having different polarities are alternately applied,
A second electrode connected to a ground line to which a ground voltage is supplied, and
Each of the first electrode and the second electrode has a rod shape,
The second electrode is arranged on the object to be heated, and the first electrode is arranged on the second electrode,
High frequency induction heating device. A plurality of the pair of electrodes is provided,
The high frequency dielectric heating device according to claim 1 . An image forming unit that forms an image on a recording medium,
The high frequency dielectric heating device according to any one of claims 1 to 3 , wherein the recording medium on which the image is formed by the image forming unit is an object to be heated.
Image forming apparatus.

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