JP4469332B2 - Grounding mechanism of image forming apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a copier, or a multifunction peripheral, and a grounding mechanism applied thereto.

  2. Description of the Related Art In recent years, image forming apparatuses such as printers, copiers, and multifunction machines have become widespread not only in offices but also in general households. Inside these image forming apparatuses, there are a large number of rotating rollers such as a conveying roller for conveying a document, an agitating roller for agitating toner, and a fixing roller for fixing toner on a printing paper. Yes.

  For example, let's take a look at an automatic document feeder (ADF). FIG. 3 is an internal structure diagram of a general automatic paper feeder 30. The document placed on the document tray 31 is taken into the automatic paper feeder 30 by the pickup roller 32 and the separation roller 33, and the deviation in the transport direction is adjusted by the registration roller 34. Then, when passing under the conveying roller 35, it is read by an image reading means 36 such as a CCD (Charge Coupled Device) and discharged by a discharge roller 37 onto a discharge tray 38.

  Here, for the sake of simplicity of explanation, the five rotating rollers of the pickup roller 32, the separation roller 33, the registration roller 34, the conveying roller 35, and the discharge roller 37 are taken up. There are also several rotating rollers.

  By the way, static electricity is generated on the surfaces of these rotating rollers due to friction caused by the rotation. If various rotating rollers are charged in this way, it may cause malfunction of the CPU and other electronic components, and there is a possibility that a predetermined operation cannot be performed. In addition, the document or paper in contact with the various rollers is charged, and the probability of occurrence of jam increases.

  In order to remove this static electricity, the rotating roller may be grounded (grounded) by some method. In general, the metal rotating shaft 51 of the rotating roller 41 as shown in FIG. 4A is attached to a mounting hole 43 provided in the side plate 44 via a conductive bearing 42 as shown in FIG. The side plate 42 is grounded.

  This structure will be described in more detail with reference to FIG. The rotary shaft 51 of the rotating roller is inserted into the conductive bearing 42, and the conductive bearing 42 is inserted into a mounting hole provided in the side plate 44. Further, the gear 52 is fitted on the shaft so as to cover the conductive bearing 42 from the outside of the conductive bearing 42. When the gear 52 is engaged with another rotating gear 53, the rotating shaft 51 is also rotated.

  In the above description, the conductive bearing 42 is composed of a cylindrical portion into which the rotary shaft 51 is inserted and a flange provided at an end portion of the cylindrical portion, and is formed on the inner periphery of the mounting hole 43 formed in the side plate 44. When the contact is made, or when the flange is in contact with the side plate 44, the rotary shaft 51 is electrically connected to the side plate 44, and the rotation roller 41 is grounded.

Various other grounding methods are disclosed in the following patent documents.
JP 2003-95463 A JP-A-5-297647 JP 2004-359443 A

  However, even if the bearing 42 is conductive, the above-described technique may be insufficient due to the process of forming the side plate 44.

  That is, the process of making the attachment hole 43 in the side plate 44 is generally performed by pressing a sheet metal. This sheet metal is usually plated to prevent rusting. However, when the mounting hole 43 is formed by press working, the inner periphery of the mounting hole 43 is not plated (in an exposed state). It comes in contact with air. For this reason, rust is generated on the inner periphery of the mounting hole 43, and electrical conduction between the conductive bearing 42 and the side plate 44 cannot be obtained, and the rotating roller 41 is not grounded.

  The present invention has been made in view of such problems. Even if rust is generated on the inner periphery of the mounting hole of the grounding side plate, the conductive bearing and the side plate are electrically connected with an inexpensive and simple structure. It is an object of the present invention to provide a grounding mechanism of an image forming apparatus capable of grounding and an image forming apparatus employing the grounding mechanism.

  In order to achieve the above object, the present invention employs the following means.

In the present invention, first, mates with interpolated cylindrical portion fitting the metal rotating shaft of the rotating roller, a conductive bearing constituted by a flange provided at an end portion of the cylindrical portion, the cylindrical portion of the bearing It is premised on a grounding mechanism of an image forming apparatus including a metal side plate having a mounting hole.

And in such a grounding mechanism, it is arranged between the opposing surfaces of the bearing and the side plate, and has a ring shape having a plurality of elastic tongue pieces formed by cutting into an L shape from the inner peripheral surface of the ring-shaped metal plate It is a metal plate, and the elastic tongue piece is configured to have elasticity by warping in the axial direction of the rotating shaft, the tip of the elastic tongue piece is brought into contact with the flange of the bearing at a plurality of points, and the ring A metal elastic material in which the main body of the metal plate is in surface contact with the side plate. Since the opposing surfaces of the side plate and the bearing are electrically connected via the metal elastic material, even if rust occurs on the inner peripheral surface of the mounting hole of the side plate, electrical communication is ensured. Further, even when the rotating roller is displaced in the thrust direction due to the elasticity of the metal elastic material, the above-described conduction is reliably ensured.

  As this metal elastic material, a ring-shaped metal plate provided with a plurality of elastic tongue pieces can be adopted. The ring-shaped metal plate is arranged with the elastic tongue facing the bearing side, and the main body of the ring-shaped metal plate is in surface contact with the side plate. As a result, even if the shaft moves or there is a poor conduction part in the side plate, the rotating roller can be reliably grounded.

  As described above, in the present invention, even if rust is generated on the inner peripheral surface of the mounting hole of the side plate, the conductive bearing and the side plate can be electrically connected with an inexpensive and simple configuration.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a grounding mechanism of the present invention and an image forming apparatus to which the grounding mechanism is applied. In FIG. 1, the side plate portion of the automatic paper feeder 10 is shown. Since the metal rotating shaft 51 of the rotating roller, the conductive bearing 42, the side plate 44, the mounting hole 43 of the side plate 44, and the gear 52 are the same as those in the background art, the description thereof is omitted.

  The grounding mechanism of the present invention is characterized in that the metal elastic material 11 is interposed between the side plate 44 and the conductive bearing 42.

  FIG. 2 is an enlarged view of a portion surrounded by a circle C1 in FIG. As shown in FIG. 2 (a), the rotary shaft 51 is fitted into the conductive bearing 42 so as to penetrate the dotted line with an arrow as in the conventional case. Further, in the present invention, the metal elastic material 11 is inserted between the flange 42b of the conductive bearing 42 and the side plate 44, and the gear 52 is attached to the flange 42b side of the conductive bearing 42.

  The metal elastic material 11 is cut into an L shape from the inner peripheral surface of the ring-shaped metal plate to form a plurality of elastic tongue pieces 12. This elastic tongue piece 12 is configured to be elastic by warping in the direction of the shaft 51 (perpendicular to the side plate 44). The direction of warping of the elastic tongue 12 may be on the side plate 44 side or on the flange 42b side of the conductive bearing 42.

  If the direction of the warping of the elastic tongue 12 is directed to the bearing 42 side, as shown in FIG. 2 (b), the body of the metal elastic material 11 is in surface contact with the side plate 44 and the tip of the elastic tongue 12 is It will come into contact with the flange 42b of the conductive bearing 42 at a plurality of points, and the metal elastic material 11 is urged between the flange 42b of the conductive bearing 42 and the side plate 44. Thereby, electrical conduction from the metal rotating shaft 51 to the contact surface of the side plate 44 is ensured via the conductive bearing 42 and the metal elastic material 11. Therefore, even if rust is generated on the inner peripheral surface of the mounting hole 43 of the side plate 44, the electrical rotation between the metal rotating shaft 51 and the side plate 44 is always ensured.

  Further, due to the elasticity of the elastic tongue piece 12, the above-described conduction is reliably ensured even when the rotating roller is displaced in the axial direction (thrust direction).

  1 and 2, the number of the elastic tongue pieces 12 is illustrated as three, but this is an example, and the number of the elastic tongue pieces 12 may be arbitrary. However, the process of actually manufacturing the metal elastic material 11 is not so complicated, and the number of the elastic tongue pieces 12 is considered to be most ideal in order to ensure the conduction.

  Moreover, as the metal elastic member 11, a wave washer can be adopted instead of the ring-shaped metal plate provided with the plurality of elastic tongue pieces 12 as described above.

  As described above, even when rust is generated in the mounting hole of the grounding side plate, it is possible to provide a grounding mechanism that achieves conduction between the bearing and the side plate with an inexpensive and simple configuration, and an image forming apparatus using the grounding mechanism.

  The grounding mechanism of the present invention has been described on the assumption that it is applied to an automatic paper feeder of an image forming apparatus. However, the grounding mechanism can be employed in other parts of the image forming apparatus.

  The grounding mechanism and the image forming apparatus according to the present invention can achieve conduction between the bearing and the side plate with an inexpensive and simple configuration even when rust is generated in the mounting hole of the grounding side plate. It is useful for multifunction devices.

1 is a diagram illustrating a configuration of a grounding mechanism of the present invention and an image forming apparatus to which the grounding mechanism is applied. The figure which shows the earthing | grounding mechanism of this invention. The figure which shows an example of the internal structure of an automatic paper feeder. The figure which shows the mode of the conventional grounding mechanism. The figure which shows the mode of the conventional grounding mechanism.

Explanation of symbols

11 Metal elastic material 12 Elastic tongue piece 41 Rotating roller 42 Conductive bearing 43 Mounting hole 44 Side plate 42b Flange 51 Rotating shaft 52 Gear

Claims (2)

Had a interpolated cylindrical portion fitting the metal rotating shaft of the rotating roller, a conductive bearing constituted by a flange provided at an end portion of the cylindrical portion, the mounting holes for fitting the cylindrical part of the bearing In a grounding mechanism of an image forming apparatus including a metal side plate,
A ring-shaped metal plate having a plurality of elastic tongue pieces, which are disposed between the bearing and the opposing surface of the side plate and cut into an L shape from the inner peripheral surface of the ring-shaped metal plate, The piece is made to have elasticity by warping in the axial direction of the rotating shaft, the tip of the elastic tongue piece is brought into contact with the flange of the bearing at a plurality of points, and the main body of the ring-shaped metal plate is connected to the side plate. A grounding mechanism for an image forming apparatus, comprising a metal elastic material in surface contact .   An image forming apparatus comprising the grounding mechanism according to claim 1.

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