Ground system

Abstract

To prevent an electronic device from becoming an antenna due to grounding, and to reduce unnecessary radiation without increasing costs by using a simple configuration.SOLUTION: A ground system 1 includes a grounded main body rail member 110, an ungrounded PF rail member 210, a resin layer 500 composed of conductive resin and electrically connected to the main body rail member 110, and a conductive leaf spring 400 electrically connected to the resin layer 500 and in contact with the PF rail member 210.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a grounding system, and more particularly to a technique for reducing unwanted radiation generated by grounding. [Background technology]

[0002] In some cases, optional devices such as a paper feeder (PF) or post-processing device are connected to the main body of an image forming device such as a digital multifunction peripheral. In such cases, the optional devices are usually grounded by electrically connecting them to the grounded main body of the image forming device via a metal plate or a leaf spring.

[0003] For example, Patent Document 1 discloses a technique for grounding an optional cassette feeder by electrically connecting the grounded metal frame of the device main body and the metal frame of the optional cassette feeder via an elastically displacing leaf spring.

[0004] Such grounding allows static electricity generated in the optional device to flow to the image forming apparatus main body and be eliminated, thereby preventing malfunction of the optional device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-241024 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a general grounding structure such as the technique disclosed in Patent Document 1, there is a problem in that the optional device acts as an antenna, worsening unwanted radiation.

[0007] The present invention has been made in view of the above circumstances, and has as its object to prevent an electronic device from becoming an antenna due to grounding, thereby reducing unwanted radiation, with a simple configuration and at low cost. [Means for solving the problem]

[0008] A grounding system according to one aspect of the present invention includes a first conductive member that is grounded, a second conductive member that is not grounded, a resin layer made of conductive resin and electrically connected to the first conductive member, and a conductive leaf spring that is electrically connected to the resin layer and in contact with the second conductive member. [Effects of the Invention]

[0009] According to the present invention, the conductivity required for grounding can be ensured while increasing impedance compared to when the first conductive member and the second conductive member are electrically connected only via a leaf spring without a resin layer. Therefore, the simple configuration can be cost-effective, preventing the electronic device from becoming an antenna due to grounding, and reducing unwanted radiation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a grounding system. [Figure 2] FIG. 2 is a front cross-sectional view showing the structure of the image forming apparatus. [Figure 3] 10 is a perspective view of the main body rail member and the PF rail member when viewed obliquely from above. FIG. [Figure 4] FIG. 2 is a perspective view of the main body rail member as viewed obliquely from below. [Figure 5] FIG. 2 is a perspective view of the leaf spring as viewed obliquely from below. [Figure 6] FIG. 1 is a cross-sectional view showing the grounding structure of the PF. [Figure 7] FIG. 10 is a cross-sectional view showing a grounding structure of a comparative example. [Figure 8] 10 is a graph showing the results of an unwanted radiation test for a comparative example. [Figure 9]10 is a graph showing the results of an unwanted radiation test for the example. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Configuration of Grounding System 1] A grounding system according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing the configuration of the grounding system 1. Referring to Fig. 1, the grounding system 1 includes an image forming apparatus 10, a PF (Paper Feeder) 20 as an optional device, and a post-processing device 30 as an optional device. The PF 20, image forming apparatus 10, and post-processing device 30 are installed side by side in this order.

[0012] The image forming apparatus 10 includes a grounded metal first frame. A main body rail member 110 is fixed to the bottom surface of the housing of the image forming apparatus 10 and the side surface on the PF20 side. The main body rail member 110 is electrically connected to the first frame of the image forming apparatus 10 by, for example, metal screws. The image forming apparatus 10 is an example of a first electronic device in the claims, and the first frame and the main body rail member 110 form a first conductive member.

[0013] The PF20 includes a second metal frame that is not grounded. A PF rail member 210 is fixed to the side of the housing of the PF20 that faces the image forming apparatus 10. The PF rail member 210 is electrically connected to the second frame of the PF20 by, for example, metal screws. The PF20 is an example of a second electronic device in the claims, and the second frame and the PF rail member 210 form a second conductive member. The grounding structure of the post-processing device 30 will be described later.

[0014] In the following description, the front side of PF20, image forming device 10, and post-processing device 30 will be referred to as the front, the back side of PF20, image forming device 10, and post-processing device 30 as the back, the upper vertical side as the top, the lower vertical side as the bottom, the side on which PF20 is located relative to image forming device 10 as the right, and the side on which post-processing device 30 is located relative to image forming device 10 as the left.

[0015] [Configuration of image forming apparatus 10] 2 is a front cross-sectional view showing the structure of image forming apparatus 10. As shown in FIG. 2, image forming apparatus 10 is a multifunction device having multiple functions such as a copy function, a transmission function, a printer function, and a facsimile function. Image forming apparatus 10 includes an image reading unit 11, an image forming unit 12, a paper feeding unit 13, and a pair of transport rollers 14.

[0016] Image reading unit 11 reads an original document using a moving original document method or a fixed original document method to generate image data. Image forming unit 12 uses an inkjet method to form an image indicated by the image data on a sheet P transported through a transport path T. Paper feed unit 13 uses a pickup roller to pull out a sheet P stored in a paper feed cassette and feeds the sheet to the transport path T. A pair of transport rollers 14 transports the sheet P on which the image has been formed to post-processing device 30. The sheet P is not particularly limited as long as it is a recording medium on which an image can be formed, but it may be, for example, recording paper or an overhead projector (OHP) sheet.

[0017] [PF20 Configuration] PF20 is a feeding device that feeds sheets P to image forming apparatus 10. PF20 includes a plurality of paper feed cassettes, a pickup roller provided in each paper feed cassette, and a transport roller. The pickup roller pulls out sheets P stored in the paper feed cassette one by one. The transport roller transports the pulled out sheets P to image forming apparatus 10.

[0018] [Configuration of post-processing device 30] The post-processing device 30 performs post-processing on the sheets P conveyed from the image forming device 10. The post-processing device 30 includes, for example, a staple unit and a folding unit. The staple unit staples the center of the stack of sheets P. The folding unit folds the stapled stack of sheets P in the center. Stapling and folding are examples of post-processing.

[0019] [Configuration of the main body rail member 110 and the PF rail member 210] Fig. 3 is a perspective view of the main body rail member 110 and the PF rail member 210 when viewed obliquely from above. Fig. 4 is a perspective view of the main body rail member 110 when viewed obliquely from below. Referring to Fig. 3, the main body rail member 110 includes a first rail 120 made of metal and a plate 130 made of metal.

[0020] Plate 130 is connected to one longitudinal end of first rail 120 so as to be perpendicular to the surface of first rail 120. Main body rail member 110 is fixed with metal screws so that first rail 120 contacts the bottom surface of the housing of image forming apparatus 10 with first rail 120 extending in the left-right direction, and plate 130 contacts the side of the housing of image forming apparatus 10 on the PF20 side. Referring to FIG. 4, two rollers 140 and a metal leaf spring 400 are provided on the surface of first rail 120 opposite to the surface contacting image forming apparatus 10.

[0021] 3, the PF rail member 210 includes a metal second rail 220 and a metal plate 230. The plate 230 is connected to one longitudinal end of the second rail 220 so as to be perpendicular to the surface of the second rail 220. The PF rail member 210 is fixed with metal screws so that the plate 230 contacts the side of the housing of the PF 20 on the image forming apparatus 10 side, with the second rail 220 extending in the left-right direction.

[0022] The cross section of the second rail 220 in the front-rear direction at the center, excluding both left and right ends, is formed into a U-shaped rectangle. The U-shaped rectangle portion of the second rail 220 is configured to be engageable with the two rollers 140 of the first rail 120. This allows the second rail 220 to slide along the first rail 120. By sliding the second rail 220, the PF20 can be moved toward or away from the image forming device 10.

[0023] [Configuration of Leaf Spring 400] Fig. 5 is a perspective view of the leaf spring 400 as viewed obliquely from below. Referring to Fig. 5, the leaf spring 400 is formed by bending a single metal plate along a bending line 400A. The leaf spring 400 includes a flat fixing portion 410 and a curved contact portion 420, which are defined by the bending line 400A. A screw hole 410A is formed in the fixing portion 410. The contact portion 420 extends obliquely from the bending line 400A at a predetermined angle in a direction away from the fixing portion 410, and is formed so that its end is curved.

[0024] [PF20 grounding structure] Fig. 6 is a cross-sectional view showing the grounding structure of PF 20. Referring to Fig. 6, fixing portion 410 is fixed to resin layer 500 made of conductive resin by screwing metal screws 610 through screw holes 410A. In this way, leaf spring 400 is electrically connected to resin layer 500.

[0025] The conductive resin constituting the resin layer 500 is not particularly limited as long as it is a commonly used resin, but examples thereof include an insulating resin into which an inorganic conductor such as metal or carbon fiber is kneaded. 3 Ω-m or more 10 5 It is preferably Ω-m or less.

[0026] Screw holes 500A are formed in resin layer 500. Metal screws 620 are threaded through screw holes 500A, thereby fixing resin layer 500 to first rail 120. In this way, resin layer 500 is electrically connected to first rail 120.

[0027] When the fixed portion 410 is fixed to the resin layer 500, the end of the contact portion 420 of the leaf spring 400 curves so as to approach, contact, and then move away from the second rail 220 as it moves away from the fixed portion 410, as viewed from the front-to-rear direction. The leaf spring 400 is electrically connected to the second rail 220 at the contact point with the second rail 220.

[0028] In this way, the main body rail member 110 and the PF rail member 210 are electrically connected via the leaf spring 400 and the resin layer 500. Therefore, the second frame of the PF 20, which is electrically connected to the PF rail member 210, is grounded via the first frame of the image forming device 10, which is electrically connected to the main body rail member 110.

[0029] [Grounding structure of post-treatment device 30] The post-processing device 30 also employs a grounding structure similar to that of the PF20. Referring again to FIG. 1, a metal post-processing device leaf spring 120 is provided on the side of the housing of the image forming device 10 facing the post-processing device 30. The post-processing device leaf spring 120 is fixed to the resin layer 500 by, for example, metal screws, in the same manner as described above. The resin layer 500 is electrically connected to the first frame of the image forming device 10 by, for example, metal screws. In this case, the first frame constitutes the first conductive member.

[0030] The post-processing device 30 includes a third frame made of metal that is not grounded. A post-processing device metal plate 310 is fixed to the side of the housing of the post-processing device 30 facing the image forming device 10. The post-processing device metal plate 310 is electrically connected to the third frame of the post-processing device 30 by, for example, metal screws. The third frame and the post-processing device metal plate 310 constitute a second conductive member. The post-processing device leaf spring 120 has a contact point with the post-processing device metal plate 310 and is electrically connected to the post-processing device metal plate 310 at the contact point.

[0031] In this way, the first frame of the image forming apparatus 10 and the post-processing device metal plate 310 are electrically connected via the post-processing device leaf spring 120 and the resin layer 500. Therefore, the third frame of the post-processing device 30, which is electrically connected to the post-processing device metal plate 310, is grounded via the first frame of the image forming apparatus 10.

[0032] [Verification of unwanted radiation intensity] The effects of the grounding system 1 will be described below based on examples and comparative examples. Note that the grounding system 1 is not limited to the following examples.

[0033] <Example> As an example, a grounding system 1 was used in which a main body rail member 110 and a PF rail member 210 were electrically connected via a leaf spring 400 and a resin layer 500 as shown in FIG.

[0034] <Comparative Example> As a comparative example, a grounding system was used in which the main body rail member 110 and the PF rail member 210 were electrically connected only via the leaf spring 400, without the resin layer 500, as shown in FIG.

[0035] The following unnecessary radiation tests were carried out on the examples and comparative examples. The test methods and test results are as follows.

[0036] <Test Method> The strength (dB (μV / m)) of electromagnetic waves at each frequency from 30 MHz to 230 MHz was measured in an anechoic chamber using an antenna placed 3 m away in the vertical direction of the grounding system. Note that the frequency band of electromagnetic waves generated in the vertical direction in the grounding system 1 of the example and the grounding system of the comparative example is 230 MHz or less, so the upper limit of the frequency band measured in the unwanted radiation test was set to 230 MHz.

[0037] <Result> Fig. 8 is a graph showing the results of an unwanted radiation test for a comparative example. Fig. 9 is a graph showing the results of an unwanted radiation test for an example. Referring to Figs. 8 and 9, the comparative example had a higher unwanted radiation intensity than the example in the frequency band from 30 MHz to 48 MHz, and some unwanted radiation with an intensity exceeding the limit line L was confirmed. On the other hand, the example had a lower unwanted radiation intensity than the comparative example in the frequency band from 30 MHz to 48 MHz, and no unwanted radiation with an intensity exceeding the limit line L was confirmed.

[0038] As shown by this result, it is clear that the grounding system 1 of the example has a reduced intensity of unwanted radiation compared to the grounding system of the comparative example.

[0039] According to the above embodiment, in the grounding system 1, the PF rail member 210 is electrically connected to the main body rail member 110 via the resin layer 500 and the leaf spring 400. Therefore, compared to connecting the main body rail member 110 and the PF rail member 210 only via the leaf spring 400 without the resin layer 500, it is possible to ensure the conductivity required for grounding while increasing impedance. This makes it possible to prevent electronic devices from becoming antennas due to grounding and reduce unnecessary radiation, with a simple configuration and at no cost.

[0040] Furthermore, according to the above embodiment, the leaf spring 400 only comes into contact with the second rail 220 that engages with and slides on the first rail 120. Therefore, even when the PF rail member 210 slides, the ground contact state is always maintained stably.

[0041] Furthermore, according to the above embodiment, the leaf spring 400 is made of metal, which makes it possible to maintain the grounded state even more reliably.

[0042] (Other variations) In the above embodiment, the leaf spring 400, the post-treatment device leaf spring 120, the main body rail member 110, the PF rail member 210, the post-treatment device metal plate 310, and other components are made of metal, but the present invention is not limited to such an embodiment. These components may be made of, for example, conductive carbon.

[0043] In the above embodiment, the PF 20 and the post-processing device 30 are described as an example of the second electronic device, but the present invention is not limited to such an embodiment. As the second electronic device, for example, other electronic devices that are detachable from the image forming apparatus 10, such as the exposure device 4 or the fixing device 7, may be used.

[0044] Furthermore, the first electronic device is not limited to an image forming apparatus, and the second electronic device is not limited to an optional device for an image forming apparatus. The first electronic device is not limited to a grounded electronic device, and may be, for example, a washing machine. The second electronic device is not limited to a grounded electronic device, and may be, for example, a clothes dryer.

[0045] In the above embodiment, the image forming apparatus 10 is an inkjet type, but the present invention is not limited to such an embodiment. The image forming apparatus 10 may be, for example, an electrophotographic type image forming apparatus.

[0046] The configuration and processing of the embodiment described above using FIGS. 1 to 9 are merely one embodiment of the present invention, and the present invention is not limited to these configurations and processing. [Explanation of symbols]

[0047] 1. Grounding System 10 Image forming device 20 PF 30 Aftertreatment device 110 Rail member for main body 120 Leaf spring for aftertreatment device 210 PF rail components 310 Sheet metal for after-treatment device 400 leaf spring 500 resin layer

Claims

1. a first conductive member that is grounded; a second conductive member that is not grounded; a resin layer made of a conductive resin and electrically connected to the first conductive member; a conductive leaf spring electrically connected to the resin layer and in contact with the second conductive member.

2. the first conductive member includes a grounded conductive first frame provided in the first electronic device, and a conductive first rail fixed to the first electronic device and electrically connected to the first frame; the second conductive member includes a second ungrounded conductive frame included in the second electronic device, and a second conductive rail fixed to the second electronic device and electrically connected to the second frame; the second rail engages with the first rail and slides to allow the second electronic device to move in a direction toward or away from the first electronic device; The grounding system of claim 1 , wherein the resin layer is fixed to the first rail, and the leaf spring is fixed to the resin layer and contacts the second rail.

3. The grounding system according to claim 1 , wherein the leaf spring is made of metal or conductive carbon.

4. the first electronic device is an image forming device that forms an image on a sheet, The grounding system according to claim 2 , wherein the second electronic device is a feeding device that feeds the sheet to the image forming device.

5. the first electronic device is an image forming device that forms an image on a sheet, The grounding system according to claim 2 , wherein the second electronic device is a post-processing device that performs post-processing on the sheet on which the image is formed.

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