JP2012118247A - Electrical apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical apparatus and an image forming apparatus that reduce the number of components and facilitate a ground work of a shielding body.SOLUTION: An electrical apparatus 1 includes a shielding body 33 made of a sheet metal, for preventing electric noise generated from electronic components from leaking to an external environment. The shielding body 33 includes a first ground part and a second ground part for grounding. The first ground part includes a first ground piece 53 formed integrally with the shielding body 33 and a fixing member 54 capable of fixing the first ground piece 53 to a support frame 30. The first ground piece 53 is fixed to the support frame 30 by the fixing member 54 to allow the shielding body 33 to be grounded. The second ground part is formed integrally with the shielding body 33 and includes elastically deformable second ground pieces 56 and 57. The second ground pieces 56 and 57 are brought into contact with the support frame 30 while being elastically deformed, to allow the shielding body 33 to be grounded.

Description

  The present invention relates to an electrical apparatus having a shield that suppresses electrical noise from leaking to the external environment, and more particularly to an image forming apparatus.

  An image forming apparatus such as a copying machine includes a main control board that controls an image forming operation for forming a toner image on a sheet. Since the main control board generates electrical noise in accordance with control of the image forming operation, the image forming apparatus includes a controller box (shielding body) that suppresses leakage of the electrical noise to the external environment (for example, Patent Document 1). ).

  The controller box covers the main control board and isolates it from the external environment, thereby suppressing leakage of electrical noise to the external environment. Such a controller box acts as an electromagnetic wave shield.

JP 2007-95967 A

  However, in Patent Document 1, the controller box is attached to the apparatus main body using a large number of screws, and the number of screws is increased as a countermeasure against electric noise. Parts costs increase. Also, the grounding work of the controller box is a complicated work.

  In view of the above circumstances, an object of the present invention is to provide an electrical apparatus and an image forming apparatus that reduce the number of components and facilitate the grounding work of a shield.

  In order to achieve the above object, an electrical device according to the present invention has a function to be controlled, an apparatus main body having a support frame made of sheet metal, and supported by the support frame to control the function. An electronic component and a sheet metal shield that is attached to the support frame in a state of covering the electronic component and suppresses electrical noise generated from the electronic component from leaking to the external environment. The support frame is grounded. The shield has a first ground part and a second ground part for grounding. The first grounding portion includes a first grounding piece formed integrally with the shield, and a fixing member capable of fixing the first grounding piece to the support frame, and the first grounding piece Is fixed to the support frame by the fixing member to ground the shield. The second grounding portion is integrally formed with the shield and includes a second grounding piece that can be elastically deformed. The second grounding piece is elastically deformed and contacts the support frame while the second grounding piece is elastically deformed. Ground.

  According to the electric device of the present invention, the first grounding piece of the first grounding portion is fixed to the support frame by the fixing member to ground the shield, whereas the second grounding of the second grounding portion. The piece is grounded by contacting the support frame using elasticity. Therefore, the number of fixing members and, in turn, the component cost can be reduced as compared with the configuration in which not only the first grounding piece but also the second grounding piece is fixed to the support frame by the fixing member. Moreover, since the second grounding piece uses elasticity, the grounding work of the shield is easy.

  In a preferred embodiment of the present invention, the support frame has a ground surface to which the shield is attached, and the shield has an edge facing the ground surface in a state of being attached to the support frame. The second grounding piece has a shape protruding from the edge and capable of contacting the grounding surface.

  According to this configuration, the shield can be grounded by a simple shape in which the second grounding piece protrudes from the edge of the shield.

  In another preferred embodiment of the present invention, the second grounding piece is formed by forming a pair of cuts in the edge, and a base end connected to the edge, and extending from the base end to the edge And a lifting piece that can be lifted with respect to the base end, and the lifting piece is lifted when it comes into contact with the grounding surface, and the shielding member is grounded by its return force. enable.

  According to this configuration, the shield is reliably grounded with a simple structure in which the second grounding piece is constituted by the base end connected to the edge and the lifting piece that can be lifted with respect to the base end. be able to.

  In still another preferred embodiment of the present invention, the fixing member is a screw.

  Although the screwing work is complicated, in the present invention, since the second grounding piece having elasticity is used, the burden of the screwing work can be reduced.

  An image forming apparatus according to the present invention includes an apparatus main body that performs an image forming operation for forming a toner image on a sheet, and the apparatus main body is an apparatus main body having the above-described configuration.

  In the electrical apparatus and the image forming apparatus according to the present invention, the grounding piece makes contact with the support frame using elasticity to ground the shield. Therefore, it is possible to reduce the number of fixing members and thus the component cost. Further, since the grounding piece uses elasticity, the grounding work of the shield is easy.

1 is an external perspective view of an image forming apparatus according to an embodiment of the present invention as viewed obliquely from the front. FIG. 2 is an external perspective view of the image forming apparatus as viewed obliquely from the rear. FIG. 3 is a rear perspective view of the image forming apparatus with the back cover and the extension cover removed. It is an expansion perspective view of a controller box. It is the perspective view which looked at the controller box from the lower part. It is the perspective view which looked at the 1st elastic contact piece from the edge side of a controller box.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of an image forming apparatus 1 according to an embodiment of the present invention when viewed obliquely from the front, and FIG. 2 is an external perspective view of the image forming apparatus 1 viewed from an oblique rear. The image forming apparatus 1 is an example of an electric apparatus according to the present invention, and illustrates an in-body discharge type multifunction peripheral. Note that terms representing directions such as “up”, “down”, “left”, “right”, “front”, and “rear” are merely for the purpose of clarifying the description, and the present invention is not limited to this. It is not intended to limit.

  The image forming apparatus 1 includes an apparatus main body 2 having a substantially rectangular parallelepiped housing structure. The apparatus main body 2 performs an image forming operation for forming a toner image on a sheet. The apparatus main body 2 includes a substantially rectangular parallelepiped lower casing 21, a substantially rectangular parallelepiped upper casing 22 disposed above the lower casing 21, and a connection that connects the lower casing 21 and the upper casing 22. And a housing 23. The lower housing 21 accommodates various devices for image formation, and the upper housing 22 accommodates various devices for optically reading a document image. An in-cylinder space surrounded by the lower casing 21, the upper casing 22, and the connecting casing 23 serves as an in-cylinder discharge unit 24 that can store a sheet after image formation.

  The in-cylinder space used as the in-cylinder sheet discharge unit 24 is open to the outside on the front surface and the left side surface of the apparatus main body 2. The user can insert his / her hand through these open portions and take out the sheet after image formation from the in-body sheet discharge unit 24. A bottom surface 241 of the internal space is defined by an upper surface of the lower housing 21.

  An operation panel unit 25 protrudes from the front surface of the upper housing 22. The operation panel unit 25 includes an operation key 251 including a numeric keypad and a start key, an LCD touch panel 252 and the like, and receives input of various operation instructions from the user. The user can input the number of sheets to be printed and the like and input the print density and the like through the operation panel unit 25. On the upper housing 22, a pressing cover 226 (not shown in FIG. 1) for pressing a document from which an image is read is disposed. The presser cover 226 is attached to the upper housing 22 so as to be rotatable at the rear edge thereof.

  The lower casing 21 is equipped with a paper feed cassette 211 that accommodates sheets to be subjected to image forming processing. The paper feed cassette 211 can be pulled out from the front surface of the lower housing 21 (apparatus body 2). The paper feeding cassette 211 is a cassette provided for automatic paper feeding.

  An image forming unit, a fixing unit, a sheet conveyance path, and the like are disposed inside the apparatus main body 2. The image forming unit performs an image forming process for forming a toner image on a sheet supplied from the paper feed cassette 211. The image forming unit includes a photosensitive drum carrying an electrostatic latent image, a charging unit for charging the surface of the photosensitive drum, an exposure unit for forming an electrostatic latent image corresponding to a document image on the surface of the photosensitive drum by a laser beam, and the like. A developing unit for forming a toner image by attaching a developer to the electrostatic latent image formed thereon, a transfer roller for transferring the toner image to a sheet, a charge removing unit for discharging the surface of the photosensitive drum after the toner image is transferred, and a residual toner on the surface of the photosensitive drum A cleaning blade or the like is provided for removing water. The fixing unit performs a fixing process for fixing the toner image transferred onto the sheet onto the sheet. The sheet conveyance path conveys the sheet from the sheet feeding cassette 211 in the order of the image forming unit, the fixing unit, and the in-body discharge unit 24. A plurality of roller pairs for conveying the sheet are arranged in the sheet conveyance path.

  The apparatus main body 2 having the above-described configuration has a plurality of exterior covers that configure the appearance of the image forming apparatus 1. Examples of such an exterior cover include a left side cover 26 that configures the appearance of the left side of the image forming apparatus 1, a back cover 27 that configures the exterior of the back side of the image forming apparatus 1, and an additional cover 28.

  The left side cover 26 includes a lower cover 262 that constitutes the appearance of the left side surface of the lower casing 21, and an upper cover 261 that constitutes the appearance of the left side face of the upper casing 22.

  The extension cover 28 constitutes the appearance of the image forming apparatus 1 in a range from a portion of the left side cover 26 near the back cover 27 to a portion of the back cover 27 near the left side cover 26.

  FIG. 3 is a rear perspective view of the image forming apparatus 1 with the back cover 27 and the extension cover 28 removed. As shown in the figure, when the back cover 27 and the extension cover 28 are removed, a back frame 30 constituting a part of the framework of the apparatus main body 2 appears. The back frame 30 is a flat plate frame made of sheet metal, and is grounded. On the surface 30a of the back frame 30 (hereinafter referred to as a ground plane), heat generated in the image forming unit, the fixing unit, the roller pair of the sheet conveying path, and the like, and heat generated in the apparatus main body 2 are externally provided. A fan 32 for discharging, a controller box 33 and the like are provided. The back frame 30 is an example of the support frame of the present invention.

  FIG. 4 is an enlarged perspective view of the controller box 33. A main control board 45 (broken line) is supported on the upper left portion of the ground plane 30a of the back frame 30. The main control board 45 is a board on which many electronic components for controlling an image forming operation for forming a toner image on a sheet are mounted. The controller box 33 has a vertically long and flat box shape that can cover the main control board 45, and is mounted on the ground plane 30 a while covering the main control board 45. The main control board 45 generates electrical noise in accordance with the operation of the mounted electronic component when controlling the image forming operation. The controller box 33 is made of sheet metal and covers the main control board 45 to act as an electromagnetic wave shield that suppresses electrical noise from leaking to the external environment. The controller box 33 is an example of a shield according to the present invention.

  The controller box 33 includes a vertically long flat plate portion 35 that extends substantially parallel to the ground plane 30 a of the back frame 30, and a side plate portion that extends from the four edges of the flat plate portion 35 toward the ground plane 30 a of the back frame 30. Have. The flat plate portion 35 is provided with an additional memory cover 42 that can be opened and closed. An optional function can be added to the image forming apparatus 1 by removing the expansion memory cover 42 and connecting the expansion memory to a connector (not shown).

  The side plate portion includes an upper plate 36 extending from the upper edge portion of the flat plate portion 35, a lower plate 37 extending from the lower edge portion, a left side plate 38 extending from the left edge portion, and a right side plate 39 extending from the right edge.

  The left side plate 38 has an edge portion (tip portion) 38a facing the ground plane 30a in a state where the controller box 33 is attached to the ground plane 30a. An extending piece 38b extending along the edge 38a is integrally formed with the edge 38a. A plurality of screw holes are formed in the extended piece 38b at a predetermined interval. By screwing a screw 54 into these screw holes, the left side plate 38 side of the controller box 33 is fixed to the grounding surface 30a. The

  Similarly, the right side plate 39 has an edge portion (tip portion) 39a facing the ground plane 30a in a state where the controller box 33 is attached to the ground plane 30a. A plurality of extending pieces 39b are integrally formed on the edge 39a at a predetermined interval along the edge 39a. Screw holes are formed in each extending piece 39b. By screwing screws 54 into these screw holes, the right side plate 39 side of the controller box 33 is fixed to the grounding surface 30a. In addition, although illustration is abbreviate | omitted, the upper side board 36 is also fixed to the ground surface 30a by the same structure. Therefore, the controller box 33 is grounded on the left side plate 38 side, the right side plate 39 side, and the upper side plate 36 side.

  Next, fixation of the lower plate 37 of the controller box 33 to the ground plane 30a will be described with reference to FIG. FIG. 5 is a perspective view of the controller box 33 as viewed from below. A plurality of through holes 43 are formed in a substantially intermediate portion in the left-right direction of the lower plate 37. The heat generated by the main control board 45 when the image forming operation is controlled is released to the outside through the through holes 43. The lower plate 37 has an edge portion 51 (tip portion) that faces the ground plane 30a in a state where the controller box 33 is attached to the ground plane 30a.

  A first elastic contact piece 56 and a second elastic contact piece 57 are integrally formed on the edge 51 of the lower plate 37. The first elastic contact piece 56 is positioned in the vicinity of one end (left end in FIG. 5) of the edge 51, and the second elastic contact piece 57 is the other end (right end in FIG. 5) of the edge 51. It is located in the vicinity.

  The configuration of the first elastic contact piece 56 and the second elastic contact piece 57 will be described with reference to FIG. FIG. 6 is a perspective view of the first elastic contact piece 56 as viewed from the edge 51 side of the controller box 33. Since the first elastic contact piece 56 and the second elastic contact piece 57 have the same shape, only the first elastic contact piece 56 will be described. The first elastic contact piece 56 has a base end portion 61 and a lifting piece 62.

  The base end portion 61 is formed with a pair of cuts 66 extending from the edge portion 51 by a predetermined distance, and is integrally connected to the lower plate 37. The base end portion 61 is substantially flush with the surface of the lower plate 37.

  The lifting piece 62 has a shape that extends integrally from the base end portion 61 and protrudes from the edge portion 51 of the lower plate 37. The lifting piece 62 has elasticity that can be lifted in a direction away from the surface of the lower plate 37 with respect to the base end portion 61.

  The lifting piece 62 includes an oblique piece 63 and a contact piece 64. The oblique piece 63 is a portion that extends obliquely from the base end portion 61 by a predetermined distance in a direction away from the surface of the lower plate 37. The contact piece 64 extends integrally from the oblique piece 63 and is set so as to be parallel to the ground contact surface 30 a of the back frame 30. A protrusion 65 is formed on the surface of the contact piece 64 that faces the ground contact surface 30a by embossing.

  When the controller box 33 is attached to the grounding surface 30a, the lifting piece 62 of the first elastic contact piece 56 contacts the grounding surface 30a via the contact piece 64, so that it is elastically deformed from the surface of the lower plate 37. It will be in the state lifted from the base end part 61 in the direction to separate. Since the lifting piece 62 is elastic, it comes into strong contact with the ground contact surface 30a by its restoring force. The degree of contact of the lifting piece 62 with the ground contact surface 30a can be changed, for example, by appropriately setting the height of the protrusion 65. Thus, by utilizing the elasticity of the lifting piece 62 of the first elastic contact piece 56, the controller box 33 can be reliably grounded at the left end of the lower plate 37. Since the second elastic contact piece 57 has the same configuration as the first elastic contact piece 56, the controller box 33 can be reliably grounded at the right end of the lower plate 37. The 1st elastic contact piece 56 and the 2nd elastic contact piece 57 are examples of the 2nd grounding piece of this invention, and comprise the 2nd grounding part. Although the first elastic contact piece 56 and the second elastic contact piece 57 have been described as having the above-described configuration, the configuration of the first elastic contact piece 56 and the second elastic contact piece 57 exhibits the characteristics of a leaf spring. If it is the structure to perform, it will not specifically limit.

  In addition to the first elastic contact piece 56 and the second elastic contact piece 57, an extending piece 52 is integrally formed on the edge portion 51 of the lower plate 37 as shown in FIG. 5. The extending piece 52 extends between the first elastic contact piece 56 and the second elastic contact piece 57 along the edge portion 51 and substantially parallel to the ground surface 30a of the back frame 30. The extended piece 52 integrally has a fixed piece 53 that further protrudes downward in FIG. 5 and extends parallel to the ground plane 30a at a position corresponding to the substantially middle portion of the lower plate 37 in the left-right direction.

  A screw hole is formed in the fixed piece 53, and the fixed piece 53 is fixed to the grounding surface 30a by screwing the screw 54 into the screw hole. As a result, the controller box 33 is attached to the ground plane 30a and grounded at a position corresponding to the substantially middle portion of the lower plate 37 in the left-right direction. The fixing piece 53 is an example of the first grounding piece of the present invention, and the screw 54 is an example of the fixing member of the present invention. In the present embodiment, the fixed piece 53 and the screw 54 constitute a first grounding portion. Although the extended piece 52 is illustrated as being in close contact with the ground contact surface 30a, it is not actually in close contact. The controller board 33 is brought into close contact with the ground plane 30 a of the lower plate 37 via the fixed piece 53, the first elastic contact piece 56 and the second elastic contact piece 57.

A first distance D1 between the screw 54 constituting the first grounding portion and the first elastic contact piece 56 constituting the second grounding portion is set to 75 mm. The second distance D2 between the screw 54 and the second elastic contact piece 57 is set to 66 mm. The main control board 45 generates an electromagnetic wave having a frequency of about 1 GHz at the maximum in accordance with the operation of the mounted electronic component when controlling the image forming operation, etc., and the first distance D1 and the second distance D2 are By setting the value to 75 mm corresponding to ¼ of the wavelength of the frequency of 1 GHz or smaller, it is possible to suppress electromagnetic waves (electric noise) from leaking from the controller box 33 to the external environment. That is, by setting the first distance D1 and the second distance D2 to 75 mm or less, the first elastic contact piece 56, the second elastic contact piece 57, and the fixed piece 53 cause the electromagnetic wave to leak out to the external environment. Can be suppressed. In other words, when the wavelength of the maximum frequency of electrical noise that is expected to be generated in accordance with the operation of the main control board 45 is λ ₀ , the controller box 33 is configured to have electrical noise by setting the distance between grounds Dn ≦ 1 / 4λ _0. Can be prevented from functioning as an antenna.

  According to the image forming apparatus 1 according to the present embodiment described above, the fixing piece 53 of the first grounding portion is fixed to the grounding surface 30a of the rear frame 30 by the screw 54, so that the controller box 33 is grounded. On the other hand, the first elastic contact piece 56 and the second elastic contact piece 57 of the second grounding portion make contact with the ground plane 30a using elasticity, thereby grounding the controller box 33. Therefore, the number of screws 54 and, in turn, the cost of parts can be reduced as compared with the configuration in which not only the first grounding piece (fixing piece 53) but also the second grounding piece is fixed to the grounding surface 30a by the screw 54. Further, since the first elastic contact piece 56 and the second elastic contact piece 57, which are the second grounding pieces, use elasticity, the grounding work of the controller box 33 is easy and the burden of complicated screwing work can be reduced. Can do.

  In the present embodiment, the second grounding piece has a simple shape in which the second grounding piece protrudes from the edge 51 of the lower plate 37 of the controller box 33, that is, each of the first elastic contact piece 56 and the second elastic contact piece 57 is provided. The controller box has a simple structure comprising a base end portion 61 formed integrally with the edge portion 51 of the lower plate 37 and a lifting piece 62 protruding from the edge portion 51 and liftable with respect to the base end portion 61. 33 is securely grounded.

  In the image forming apparatus 1 according to the present embodiment described above, the configuration in which the first elastic contact piece 56 and the second elastic contact piece 57 constituting the second grounding portion are provided on the lower plate 37 side of the controller box 33 will be described. However, the second grounding portion is not limited to the lower plate 37, and may be provided, for example, at the edge 38 a of the left plate 38. Thereby, the number of screws 54 can be further reduced.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 27 Back cover 28 Additional cover 30 Back frame (support frame)
30a Ground plane 33 Controller box (shield)
37 Lower plate 45 Main control board (electronic components)
51 Edge 52 Extension piece 53 Fixing piece 54 Screw (fixing member)
56 First elastic contact piece (first grounding piece)
57 Second elastic contact piece (second grounding piece)
61 Base end 62 Lifting piece 66 Cut

Claims (5)

An apparatus main body having a controlled function and having a support frame made of sheet metal;
An electronic component supported by the support frame and for controlling the function;
A sheet metal shield that is attached to the support frame in a state of covering the electronic component and suppresses electrical noise generated from the electronic component from leaking to the external environment,
With
The support frame is grounded;
The shield has a first ground part and a second ground part for grounding,
The first grounding portion includes a first grounding piece formed integrally with the shield, and a fixing member capable of fixing the first grounding piece to the support frame, and the first grounding piece Is fixed to the support frame by the fixing member to ground the shield,
The second grounding portion is formed integrally with the shield and has a second grounding piece that can be elastically deformed. The second grounding piece is elastically deformed and contacts the support frame while the second grounding piece elastically deforms. Electrical equipment to be grounded. The electric device according to claim 1,
The support frame has a ground plane to which the shield is attached;
The shield has an edge facing the ground plane in a state of being attached to the support frame;
The second grounding piece is an electrical device having a shape that protrudes from the edge and can contact the grounding surface. The electrical device according to claim 2,
The second grounding piece is formed with a pair of cuts in the edge, a base end connected to the edge, and extends from the base end and protrudes from the edge, with respect to the base end And a liftable liftable piece,
The lifting piece is in a state where it is lifted when it comes into contact with the grounding surface, and the shield can be grounded by its restoring force. In the electric equipment according to any one of claims 1 to 3,
The electric device in which the fixing member is a screw.   An image forming apparatus having an apparatus main body for performing an image forming operation for forming a toner image on a sheet, wherein the apparatus main body is the apparatus main body according to claim 1.

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