Rollers

A roller comprising a straight support member, a plurality of hollow cylindrical roller members arranged axially thereof and having the support member inserted therethrough, and a position change-over device provided for each of the roller members, each of the roller members being provided around the support member so as to be rotatable relative to the support member and movable relative thereto in a plane orthogonal to the axial direction, the position change-over device being adapted to shift the roller members respectively each in the plane orthogonal to the axial direction of the roller member, the roller being characterized in that a connecting member is interposed between opposed end faces of each two adjacent roller members for preventing the two adjacent roller members from moving circumferentially thereof relative to each other while permitting relative movement of the two adjacent roller members in the plane orthogonal to the axial direction.