JP2008052222A5 - - Google Patents

Claims (7)

  A belt unit used in an image forming apparatus for transferring a toner image formed on an image carrier to a transfer material, and comprising a rotating endless belt body and a convex portion provided on an inner surface of the belt body A member and a plurality of rollers that stretch the inner surface of the belt member, and a direction intersecting a rotation direction of the belt member by contacting the convex portion with at least one of the plurality of rollers. In the belt unit that regulates movement to
  The convex portion has at least one seam in the rotation direction of the belt member, and a thickness of the convex portion adjacent to the seam is smaller in the protruding direction than other portions of the convex portion. A belt unit having a thin portion, wherein the seam is formed by the thin portion and the thin portion facing each other in the rotation direction of the belt member.   When the belt member moves in the intersecting direction, one of the plurality of rollers is in contact with the convex portion, and the winding amount of the belt member around the roller in contact with the convex portion is The total length of the seam in the rotation direction of the belt member and the length of the thin part adjacent to the seam is smaller than the amount of wrapping of the belt member around the other roller that does not contact the convex part, 2. The belt unit according to claim 1, wherein the belt unit is smaller than a winding amount of the belt member around a roller in contact with the convex portion.   The thickness in the protruding direction of the other portion of the convex portion is a predetermined thickness, and the length of the thin portion in the rotation direction of the belt member is larger than the predetermined thickness. Alternatively, the belt unit according to claim 2. The convex part is formed by stacking a plurality of layers, and the number of thin layers of the convex part is less than the number of laminated parts of other parts of the convex part . The belt unit according to any one of the above . The thin portion, the Oite the rotational direction of the belt member, either one of claims 1-3, wherein the projecting direction of the thickness, wherein the continuous manner small and Turkey toward the seam The belt unit described in 1 . The belt unit according to any one of claims 1 to 5, wherein the belt member is a transfer material conveyance body that carries and conveys a transfer material onto which an image formed with toner is transferred. . 6. The belt unit according to claim 1 , wherein the belt member is an intermediate transfer member to which an image formed with toner is transferred.