Toner conveyance device including conveyance screw and image forming apparatus

{
  "publication_number": "US11493862B2",
  "country": "US",
  "kind": "B2",
  "title": "Toner conveyance device including conveyance screw and image forming apparatus",
  "abstract": "An image forming apparatus (1) includes a casing (21) having a toner conveyance path (34); a screw (24) conveying a toner in the toner conveyance path (34) in a predetermined conveyance direction; and a downstream side bearing (25) rotatably supporting a downstream side end portion of the screw (24) in the conveyance direction, wherein the screw (24) includes: a shaft (51) extending in the conveyance direction; and a spiral fin (52) provided around an outer circumferential face of the shaft (51), the shaft (51) has a downstream side insertion part (54) inserted into the downstream side bearing (25), and the downstream side insertion part (54) has an outer diameter larger than an outer diameter of a downstream side end portion of the fin (52) in the conveyance direction.",
  "claims": [
    "1. A toner conveyance device comprising: a casing having a cylindrical duct extending in a predetermined conveyance direction, and provided with a toner conveyance path in the duct; a screw conveying a toner in the toner conveyance path in a predetermined conveyance direction; and a downstream side bearing rotatably supporting a downstream side end portion of the screw in the conveyance direction, wherein the screw includes: a shaft extending in the conveyance direction; and a spiral fin provided around an outer circumferential face of the shaft, the shaft has a downstream side insertion part inserted into the downstream side bearing, the downstream side insertion part has an outer diameter larger than an outer diameter of a downstream side end portion of the fin in the conveyance direction, the duct has a flange protruded radially outward on a downstream side end portion of the duct in the conveyance direction, and the flange covers a gap between the downstream side insertion part and the downstream side bearing from an upstream side in the conveyance direction.",
    "2. The toner conveyance device according to claim 1, wherein the gap between the downstream side insertion part and the downstream side bearing is disposed radially outward from the downstream side end portion of the fin.",
    "3. The toner conveyance device according to claim 1, wherein a film-shaped seal member is disposed between the flange and the downstream side insertion part.",
    "4. The toner conveyance device according to claim 1, wherein a holder is protruded toward a downstream side in the conveyance direction on a radially outer end portion of the flange, and the downstream side bearing is held by the holder.",
    "5. The toner conveyance device according to claim 1, wherein the outer diameter of the downstream side insertion part is larger than an inner diameter of a downstream side end portion of the toner conveyance path in the conveyance direction.",
    "6. The toner conveyance device according to claim 1, further comprising an upstream side bearing rotatably supporting an upstream side end portion of the screw in the conveyance direction, wherein the shaft further has an upstream side insertion part inserted into the upstream side bearing, and the upstream side insertion part has an outer diameter smaller than an outer diameter of an upstream side end portion of the fin in the conveyance direction.",
    "7. The toner conveyance device according to claim 1, wherein the duct has a toner communication port on a downstream side in the conveyance direction.",
    "8. An image forming apparatus including the toner conveyance device according to claim 1."
  ],
  "description_excerpt": "The present invention relates to a toner conveyance device and an image forming apparatus.\n\nAn electrophotographic type image forming apparatus includes a toner conveyance device which conveys a toner to be supplied to an image carrier (such as a photosensitive drum and an intermediate transferring belt) or conveys a waste toner collected from the image carrier. For example, a toner conveyance device may include a casing having a toner conveyance path, a screw conveying a toner in the toner conveyance path and bearings to which both end portions of the screw are rotatably supported (see Patent Document 1).\n\nPatent Document [Patent Document 1] Japanese Patent laid-open Publication No. 2018-159874\n\nProblems to be Solved by the Invention In the above toner conveyance device, in order to smoothly rotate the screw with respect to the bearings, it is preferable to provide a slight gap between both end portions of the screw and the bearings. However, if the gap is provided between both end portions of the screw and the bearings in the above manner, there is a possibility that the toner leaks to the outside of the toner conveyance device through the gap. In particular, when the toner is conveyed in a predetermined conveyance direction by the screw, the toner is pressed with a large force to the gap between the bearing and the downstream side end portion of the screw in the conveyance direction. Accordingly, the toner easily leaks to the outside of the toner conveyance device through the gap.",
  "cpc": [
    "G03G 15/0891",
    "B65G 33/22",
    "G03G 15/0893",
    "G03G 15/0898",
    "G03G 21/105",
    "G03G 2215/0827",
    "G03G 2215/0838"
  ],
  "ipc": [
    "B65G 33/22",
    "G03G 15/08",
    "G03G 21/10"
  ],
  "assignees": [
    "KYOCERA DOCUMENT SOLUTIONS INC"
  ],
  "inventors": [
    "MIZUTANI NAOKI",
    "TOMIMORI KOSHIRO"
  ],
  "filing_date": "2020-01-22",
  "publication_date": "2022-11-08",
  "grant_date": "2022-11-08",
  "priority_date": "2019-02-07",
  "application_number": "US-202017429261-A",
  "family_id": "71947049",
  "citations": [
    "JP2009053577A",
    "JP2015215474A",
    "JP2018159874A",
    "US10175611B2",
    "US2018275562A1"
  ]
}